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Full text of "Geology And Geophysics Vol XII"

DO 

64927 



CD 



Published by the 
SECRETARIAT, NINTH PACIFIC SCIENCE CONGRESS 

DEPARTMENT or SCIENCE 
BANGKOK, THAILAND 

1961 



PUBLIC A i JUJN eujvnvn i i tit 

and 
EDITORIAL STAFF 

Chairman: DR. CHARNG RATANARAT 
Vice-Chairman: M.R. CHAKRATONG TONGYAI 

MR. WELLINGTON BRINK PROF. NOPAKHUN TONGYAI 

MR. D. V. SASSOON MRS. CATHERINE F. SIFFIN 

MR. PUE ROCHANAPURANANDA DR. LYD1A NA RANONG 

MRS. M. ISABELLE FARRAR, Secretary 
This volume is edited by: Prof. Dr. Th. H. F. Klompe (Bangkok) 



PRINTED AT THAI WATANA PANICH, (R.O.P.), RAMA I ROAD, BANGKOK. BOONPRING T.SUWAN, PRINTER. B.C. 2504- 



EDITOR'S NOTE 

At the meeting of the Committee on Publications of the Ninth Pacific Science Congress, it was 
agreed that the increasing number of communications and papers presented at each Congress has 
become a very difficult problem for the Publication Committee and the editorial staff to cope with and 
that too much time is required to complete the publication of the Proceedings; therefore, it was recom- 
mended that the following principles governing publication be followed: 

a. That invited contributions to the scheduled symposium be published in full; 

b. That reports of the Standing Committees be published in full ; 

c. That other papers submitted to the Congress during its sessions be published in abstract only, 
the abstract not to exceed 500 words ; 

d. That papers which, though listed on the program or included in the pre-Congress abstracts 
published in advance but not actually submitted to the Congress at its sessions, should be 
disregarded: 

e. That authors be asked to indicate by a definite and early date 1 whether they prefer to publish 
their papers in sources other than the Congress Proceedings; that if this is done, the Congress 
should be acknowledged; 

f. That all proofreading be the responsibility of the editorial committee, and that this committee 
shall consider the manuscripts in their hands by a definite date as final; 2 

g. That authors be held responsible for submitting their material in good English; 

h. That on matters arising during the course of publication and not specifically covered in the 

statement of policy the editorial committee is empowered to act. 

In accordance with the resolutions of the Committee, the editorial board has edited the reports and 
manuscripts where necessary to bring uniformity and consistency to the format. Typographical and 
grammatical errors as well as errors in phraseology, spelling, or technical terms have been corrected, 
wherever possible, but in cases where the exact meaning of the original copy was not clear, the text has 
been left as submitted by the author. 

In order to reduce the cost and bulk of the publication, appendices, illustrations, and exhibits when- 
ever considered not vital to the text have been eliminated. 

If an author requested to publish elsewhere, his paper has been mentioned in the footnote under 
the respective titles, but if an author who presented a paper at the Congress failed to submit his manu- 
script either in full or in abstract, his paper and the discussions thereon have been eliminated entirely. 

It was also decided that, in order to complete the publication of the Proceedings as soon as possible, 
each division be published in a separate volume. Short volumes or the ones that do not require too much 
editorial work will be released first. Therefore, among the twenty volumes planned, any volume may 
appear first. They will not appear in consecutive order. 

The editorial board wishes to thank all authors who were prompt in submitting their revised manu- 
scripts in good form and, in particular, members of the Standing and Organizing Committees, too 
numerous to be named, who have helped in collecting the manuscripts pertaining to their respective 
divisions. 

The Board wishes in particular to thank Dr. F. Raymond Fosberg for going over and correcting 
the Special Symposium on Climate, Vegetation, and Rational Land Utilization in the Humid Tropics 
under Unesco; 

Mr. Saman Buravas of the Royal Mines Department for helping by redrawing charts and maps 
in order that they might reproduce clearly when printed; 

Mr. J. Alan Tubb of the FAO Regional Office, for his assistance in going over and clarifying some 
of the papers in the Fisheries and Oceanography volumes and in translating some of the French papers; 

Dr. Pradisth Cheosakul of the Department of Science for editing the Chemistry in the Development 
of Natural Resources volume; 

Last but not least, the Board wishes to thank the Thai Watana Panich Press for their cooperative ef- 
forts, far beyond the requirement of the contract, in devoting all their resources to printing these volumes. 



1 January 1, 1958, in the case of the Ninth Congress. 

2 March 1, 1958, in the case of the Ninth Congress. 



ABBREVIATION S 



APFC 

CAA 

CSIRO 

ECAFE 

EQUAPAC 

FAO 

IACOMS 

ICA 

ICAO 

ICSU 

IGY 

IPFC 

IRC 

JCRR 

NORPAC 

PHILCUSA 

PIOSA 

SEATO 

SPC 

UN 

UNESCO 

UNICEF 

USDA 

USIS 

USOM 

WHO 

WMO 



Asia-Pacific Forestry Commission 

Civil Air Administration 

Commonwealth Scientific and Industrial Research Organization (Australia) 

Economic Commission for Asia and the Far East 

Equatorial Pacific (oceanographic survey) 

Food and Agriculture Organization 

International Advisory Committee on Marine Sciences 

International Cooperation Administration 

International Civil Aviation Organization 

International Council of Scientific Unions 

International Geophysical Year 

Indo-Pacific Fishery Commission 

International Rice Commission (FAO) 

Joint Commission on Rural Reconstruction (Taiwan, China) 

North Pacific (oceanographic survey) 

Philippine Council for United States Aid 

Pan-Indian Ocean Scientific Association 

South-East Asia Treaty Organization 

South Pacific Commission 

United Nations 

United Nations Educational, Scientific and Cultural Organization 

United Nations International Children's Emergency Fund 

United States Department of Agriculture 

United States Information Service 

United States of America Operations Mission 

World Health Organization 

World Meteorology Organization 



PARTICIPANTS t 

ALCARAZ, ARTURO, Chief Volcanologist, Commission on Volcanology, National Research Council of 
the Philippines, University of the Philippines, Quezon City, Philippines. 

ANDERSON, ALLEN E., Geographer, U.S. Army Map Service, Far East (Tokyo, Japan), APO 500, San 
Francisco, California, U.S.A. 

AUBERT DE LA RUE, EDGAR, Geologist, Centre National de la Recherche Scientiiique, 18, rue Ribera, 
Paris XVI e , France. 

BENOIE, RENE, Charge de Cours a la Faculte des Sciences de Saigon, haculte des Sciences, Saigon, 
Vietnam. 

BINSON, BOON ROD, Secretary -General, National Energy Authority, Royal Palace, Bangkok, Thailand. 

BIO, CUING CHANG, Director, Geological Survey of Taiwan, P.O. Box 31, Taipei, Taiwan, Republic of 
China. 

BISAI.BUTRA, BANCHONG, Engineer, Hydro-energy Division, Royal Irrigation Department, Ministry of 
Agriculture, Samscn, Bangkok, Thailand. 

BLUMINSTOCK, DAVID i , United States Weather Bureau, P.O. Box 3650, Honolulu, Hawaii. 

BRADFORD, ERNEST F., Acting Deputy Director. Geological Survey, Tiger Lane, P.O. Box 1015, 
Ipoh, Federation of Malaya. 

BROUWER, H.A., Professor, Municipal University of Amsterdam, Stadionweg 90, Amsterdam, 
Netherlands. 

BUELARD, EDWARD CRISP, Physicist, Department of Geophysics, Madingly Rise, Madingly Road, 
Cambridge, England. 

BURAVAS, SAMAN, Chief Geologist, Royal Department of Mines, Ministry of Industry, Rama VI Road, 
Bangkok, Thailand. 

BURAVAS, SMAK, Manager, Sara Bun Marble Quarry, Thai Marble Corporation, Bangkok, Thailand. 

CHARAL-JAVANAPHET, JUMCEiET, Geologist, Royal Department of Mines, Ministry of Industry, 
Rama VI Road, Bangkok, Thailand. 

CHRISTIAN, c.s.. Chief, Division of Land Research, C.S.I.R.O., Box 109. Canberra City, A.C.T., 
Australia. 

DAVIS, SYDNEY GEORGE, Professor and Head, Department of Geography and Geology, University of 
Hong Kong, Hong Kong. 

DRUMMOND, ROBERT R., Fulbright Foundation Lecturer, University College, Mandalay, Burma. 
EMERY. K.O., Professor of Geology, LJniversity of Southern California, Los Angeles, California, U.S.A. 

i AIRBRIDGE, RHODES w.. Department of Geology, Columbia University, New York 27, New York, 
U.S.A. 

POSTER, HELEN L., Geologist, U.S. Geological Survey, U.S. Army Map Service, Military Geology 
Branch, APO 500, San Francisco, California, U.S.A. 

GARDNER, LOUIS SAMUEL, Chief, Geology and Mining, USOM/Thailand, c/o American Embassy, 
Bangkok, Thailand. 

GASKELL, THOMAS F., Chief Physicist, Exploration Department, British Petroleum Company Ltd., 
Britannic House, Finsbury Circus, London, E.C. 2, England. 

t Initials or names in italics represent Thai titles. 



GRINDLEY, GFORGE WILLIAM, Geologist, New Zealand Geological Survey, Box 8002, Wellington, 
New Zealand. 

HAMILTON, EDWIN L., Supervisor, Sea-Floor Studies Section, U.S. Navy Electronics Laboratory, San 
Diego 52, California, U.S.A. 

HILLS, EDWIN SHERBON. Professor of Geology, Department of Geology, University of Melbourne, 
Carlton N. 3, Victoria, Australia. 

JALICHAN, NITIPAT, Geologist, National Energy Authority, Royal Palace, Bangkok, Thailand. 
JOHNSON, j. HARLAN, Professor of Geology, Colorado School of Mines, Golden, Colorado, U.S.A. 

JOHNSON, ROBERT B., Chief Analyst, Operations Analysis Office, Hq. Pacific Air Forces, Hickam Air 
Force Base, Hawaii. 

JOHNSON, WILLIAM D., JR., Chief, Foreign Geology Branch, U.S. Geological Survey, Washington 25. 
D.C., U.S.A. 

JONES, C.R., Geologist, Geological Survey, Grik, Perak, Federation of Malaya. 

KANCHANALAK, BOONCHOB, Engineering Hydrologist, Royal Irrigation Department, Ministry of Agri- 
culture, Samsen, Bangkok, Thailand. 

KARUS, FVGENI VILIAMOVICH, Director, Institute of Earth Physics, Academy of Sciences of the USSR, 
Bolshaya Kaluskaya 14, Moscow, USSR. 

KLOMPC TIL H.F., Professor, Department of Geology, University of Indonesia, Djl. Ganeca 10, 
Bandung, Indonesia. Presently: Department of Geology, Chulalongkorn University, 
Bangkok, Thailand. 

KOBAYASHI, TEiiCHi, Professor, Geological Institute, University of Tokyo, Tok>o, Japan. 

KOLESNIKOV, ARKADY, Head, Scathermic Laboratory, Marine Hydrographical Institute, Academy of 
Sciences of the USSR, Moscow, USSR. 

KOMAIARJUN, PUMWARN, Geologist, Royal Department of Mines, Ministry of Industry, Rama VI 
Road, Bangkok, Thailand. 

LAMOTT, KENNETH L.. Worldwide Surveys, Inc., 224 East Eleventh Street, Los Angeles 15, California, 
U.S.A. 

LiNSENMEYfcR, ROY F., Assistant Professor, Swarthmore College, Swarthmore, Pennsylvania, U.S.A. 

LONG, WAYNL L.. Engineering Technical Advisor, Faculty of Engineering, Chulalongkorn University/ 
University of Texas ICA Contract, Bangkok, Thailand. 

MA, TING YING H., Professor, Department of Geology, National Taiwan University, Taipei, Taiwan, 
Republic of China. 

MASON, BRIAN HAROLD, Curator of Geology, American Museum of Natural History, New York 24, 
New York, U.S.A. 

NA CHIANGMAI, PONGPAN, Geologist, Geological Survey Division, Royal Department ot Mines, Ministry 
of Industry, Rama VI Road, Bangkok, Thailand. 

NESBITT, PAUL H., Chief, ADT Division, Research Studies Institute, Air University (USAF), Maxwell 
Air Force Base, Alabama, U.S.A. 

O'DRISCOLL, DESMOND, Assistant Chief Geologist, Bureau of Mineral Resources, Geology and Geo- 
physics, Canberra, A.C.T., Australia. 

PATTABONGSE, PiSET, College of Engineering, Chulalongkorn University, Bangkok, Thailand. 
RANKIN, P.A., Technical Manager, Hunting Geophysics Ltd., Borehamwood, Herts, London, England. 



REESE, H. DARWIN, Biochemist, Kasetsart University/Oregon State University 1CA Contract, Bangkhen, 
Bangkok, Thailand. 

REVELLE, ROGER, Director, Scripps Institution of Oceanography, University of California, La Jolla, 
California, U.S.A. 

ROE, F.W., Director, Geological Survey Department, Kuching, Sarawak. 
RUHLE, GEORGE CORNELIUS, Park Naturalist, Hawaii National Park, Hawaii. 

ST.-AMAND, PIERRE, Head, Optics Branch, Research Department, Michelson Laboratory, Code 5018, 
U.S. Naval Ordnance Test Station, China Lake, California, U.S.A. 

SALWIDHAN-NIDES, LT. GENERAL Phya, President of Science Society of Thailand and Professor of 
Geodetics and Astronomy, Chulalongkorn University, Bangkok, Thailand. 

SETHAPUT, VIJA, Director-General, Royal Department of Mines, Ministry of Industry, Rama VI 
Road, Bangkok, Thailand. 

SIIEPARD, FRANCIS PARKER, Professor, Scripps Institution of Oceanography, University of California, 
La Jolla, California, U.S.A. 

SHTCHERBAKOV, DMITRI, Chief, Geological and Geographical Branch, Academy of Sciences of the 
USSR, Bolshaya Kaluskaya 14, Moscow, USSR. 

SNIDWONGSE, PAKPONGSNID, Lecturer, Mathematics Department, Chulalongkorn University, Bangkok, 
Thailand. 

SUNDARA-VICHARANA, YEN, Professor, Physics Department, Chulalongkorn University. Bangkok, 
Thailand. 

THOMPSON, WARREN CHARLES, Associate Professor of Oceanography and Aerology, Department of 
Aerology, U.S. Naval Postgraduate School, Monterey, California, U.S.A. 

TOWNSEND, GUORGE E., Geographer, U.S. Army Map Service, Far East (Japan), APO 500, San Fran- 
cisco, California, U.S.A. 

TRINH, NGUYEN QUANG, Recteur, Universite de Saigon, Saigon, Vietnam. 

TROLL, CARL TH., Professor, Universititat Geographisches Institut, Bonn, Germany. 

VEERABURUS, MANAS, Geologist, Royal Department of Mines, Ministry of Industry, Rama VI Road, 
Bangkok, Thailand. 

WIENS, HEROID j., Associate Professor, Department of Geography, Yale University, New Haven, 
Connecticut, U.S.A. 



in 



GEOLOGY AND GEOPHYSICS 



Standing Committee Chairman: JAMES HEALY 
Organizing Committee Chairman: LIEUTENANT-GENERAL PHYA SALWIDHAN-NIDES 



Standing Committee Reports 

REPORT OF THE CHAIRMAN OF THE STANDING COMMITTEE 
ON PACIFIC GEOLOGY AND GEOPHYSICS! 

JAMES HEALY 

Geological Survey t Rotorua, New Zealand. 



INTRODUCTION 

At the Eighth Pacific Science Congress held 
in Manila in 1953 a change in organization of the 
division of Geology and Geophysics was recom- 
mended by the members present. It was pro- 
posed that eight standing committees be set 
up, which would between them cover the fields 
of geology and geophysics. Each was to circulate 
up-to-date information amongst its members and 
maintain a bibliography. 

The Council in its final session approved the 
appointment of a single Chairman for one 
Standing Committee for Geology and Geophys- 
ics. This was intended to simplify the manage- 
ment of the division, by leaving it open to the 
chairman to organize sub- committees along the 
lines proposed above. However, there was some 
difficulty in filling the position and the present 
chairman was not appointed for some time. 
Approaches were made to a number of geologists 
to take over sub -committees, but the response 
was poor, mainly because it would be necessary 
to spend time on organization that could be 
better spent on research. 

The proposed organization has not therefore 
been pushed, and latterly a Committee has been 
formed as representative as possible in the time 
available to the Chairman, and brief accounts 
of geological and geophysical developments 
since the last Congress were requested, together 
with any suggestions for projects of Pacific inter- 



est on which the next Standing Committee might 
work. 

From the reports received the report that 
follows has been compiled, but no suggestions 
for research projects have been received. The 
writer is of the opinion that it would be desirable 
either to organize the Standing Committee along 
lines somewhat different from those suggested 
at the last Congress, or to return to a limited 
number of Standing Committees as formerly 
instead of just the one. Two suggestions are 
put forward here for projects either as Standing 
Committees or as sub -committees of a single 
Standing Committee. 

(1) Pleistocene Research, to embrace the 
correlation of research in stratigraphy, geochro- 
nology, glaciology, oceanography. The chance 
to elucidate and correlate earth history in all its 
aspects can be more appropriately applied to the 
Pleistocene, and more particularly during the 
latter part of the Pleistocene, than to any other 
period. 

(2) Geothermal Research in its wider aspects, 
to embrace volcanism, hydro thermal geology 
and heat flow generally, as distinct from the ear- 
lier Standing Committee for Volcanology, with 
undue emphasis on purely volcanic events. 

If it be granted that an organization such as 
the Pacific Science Association can become 
topheavy with too many Committees, and it is 
desired to maintain elasticity as favoured by the 



t Presented by Mr. Arturo Alcaraz, University of the Philippines, Quezon City. 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



founder, the late Professor J.W. Gregory, then 
these committees or sub-committees could 
have a limited life. A specific committee could 
be formed to perform certain functions, or 
accomplish certain ends, and once that had 
proceeded to the stage where it became desirable 
to disband it in favour of another one, that 
could be done. It seems certain that some of the 
earlier Standing Committees may have outlived 
their necessity when considered in relation to new 
problems. 

It is also suggested that the Standing Com- 
mittee or Committees concentrate specifically on 
problems or projects for the following Congress. 

PACIFIC BIBLIOGRAPHY 

As requested at the Seventh Pacific Science 
Congress, a report on the preparation of a biblio- 
graphy of the geology of the Pacific was prepared 
and submitted by Charles G. Johnson at the 
Eighth Congress. It is published in Vol. 2 of 
the Proceedings of the 8th Pacific Science Con- 
gress (pp. 3-5). Mr. Johnson now reports 
that no further progress has been made on the 
bibliography. He is of the opinion that although 
there is still a need for a bibliography, that need 
is not as pressing as it was immediately after 
World War II, and that current bibliographies 
published by the Geological Society of America, 
the American Geophysical Union, the New 
Zealand Geological Survey and others, satisfy 
most needs. He suggests that the project be 
dropped or transferred to someone else in better 
position to negotiate for funds to support it. 

Helen L. Foster prepared an annotated biblio- 
graphy of the Geology and Soils Literature of 
Western North Pacific. 

In addition to the regular bibliographic 

sections published in certain journals, attention 

is drawn to the following publications of interest: 

Catalogue of translations of Japanese geological 

literature of the Pacific Islands. Prepared by 

Geological Surveys Branch, Intelligence 

Division, Office of the Engineer, HQ, United 

States Army Forces, Far East, with personnel 

of the U.S. Geological Survey. April, 1954. 

Abstracts of papers on New Zealand geology 
published during 

- 1949. N.Z. Jour. Sci. & Tech. 33B, 61-72, 1951 

-1950. 33B, 234-244, 1951 

-1951. 34B, 189-204, 1952 

-3952. 35B, 284-297, 1953 

-1953. 36B, 411-428, 1955 

-1954. 37, 416-435. 
2 



Bibliography of New Zealand Oceanography. 
Geophysical Memoir 4. N.Z. Oceanographic 
Institute, Wellington 1955. 

Publications on the geology and geophysics of 
Indonesia and adjacent areas, 1952-1953. 
Indonesian Jour, for Nat. Set., Vol. 1 10 
1954. Compiled by Th. Klomp. Addenda .... 
Indonesian Jour, for Nat. Sci., Vol. 111. 

Publications on the geology and geophysics of 
Indonesia and adjacent areas, 1954. Indo- 
nesian Jour, for Nat. Sci., Vol. Ill, 1955. 
Compiled by Th. Klompe. 

Bibliography of Philippine Geology, Mining and 
Mineral Resources. Juan S. Teves. Bureau 
of Mines, Bibliography Series No. 1. 1953. 

Report of the Standing Committee on Volcano- 
logy. Compiled by J. Healy. Proc. 8th 
Pac. Sci. Cong. Vol. 11, 7-61, 1956. Con- 
tains references to most important volcano- 
logical papers published during period 
1949-1953. 

Report of the Standing Committee on Datum- 
planes in the Geological History of the 
Pacific Region. R.S. Allan. Proc. 8th Pac. 
Sci. Cong. Vol. 11, 325-423. A Com- 
prehensive account of stratigraphic correla- 
tion in the Pacific region, including a 
massive bibliography. 

STRATIGRAPHIC CORRELATION 

In view of the importance of this subject to 
Pacific geology, Dr. R.S. Allan was asked to 
compile an account of developments in strati- 
graphic correlation since the last Congress, and 
his report will be appended separately. 

INTERNATIONAL GEOPHYSICAL YEAR 

Geophysicists in the Pacific region will spend 
a considerable amount of time during the next 
year or two on projects connected directly and 
indirectly with the International Geophysical 
Year. Conceived originally by a small bunch of 
scientists, this project has caught the imagination 
of peoples and governments the world over, and 
the next two years will see the amassing of an 
amount of data that will keep geophysicists and 
geologists on their toes for years to come. 
Arrangements have been made for the Annals 
of the International Geophysical Year to be 
published by the Pergamon Press Ltd., London. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



CANADA 

STANDING COMMITTEE MEMBERS 

Dr. G.B. Leech, Geological Survey of Canada, 
Victoria Museum, Ottawa, Canada. 

Dr. L.W. Morley, Chief Geophysicist, Geologi- 
cal Survey of Canada, Victoria Museum, 
Ottawa, Canada. 

Professor W.H. Mathews, University of British 
Columbia, Vancouver 8, Canada. 

The death of a former member of the Standing 
Committee for Volcanology, Dr. W.E. Cock- 
field, is recorded with regret. 

VOLCANIC GEOLOGY 

Professor Mathews has supplied the follow- 
ing information on volcanic geology in Canada 
since 1953. No volcanic activity has been 
Reported, and significant literature is confined 
to the study of late and post -Pleistocene lavas 
and pyroclastics, concerning which three papers 
are worthy of mention. 

Bostock, H.S., 1952, Geology of North-west 
Shakwak Valley, Yukon Territory. GeoL 
Surv. Canada, Mem. 267. 

Contains a discussion (p. 36-39) of the 
character and distribution in Yukon Ter- 
ritory of a well-known deposit of volcanic 
ash approximately 1,400 years in age. 
Rigg, G.B. and Gould, H.R., 1957, Age of 
Glacier Peak eruption and chronology 
of post-glacial peat deposits in Washing- 
ton and surrounding areas. Am. Jour. 
Set. 255, 341-363. 

Describes an ash deposit about 6,700 
years old, which may have extensions into 
southern British Columbia. 
Mathews, W.H., 1957, Petrology of Quater- 
nary volcanics of the Mt. Garibaldi 
map-area, Southwestern British Columbia. 
Am. Jour. Sci. 255, 400-415. 
Recent reconnaissance work by the Geological 
Survey of Canada in the Stikine River area has 
discovered striking signs of postglacial volcanic 
activity. Nothing of this activity has as yet been 
published beyond a note by F.E. Wright (The 
Unuk River Mining region of British Columbia, 
Geol. Surv. Canada Summ. Rept, for 1905, 
46-53, 1906). This includes the remark, "The 
volcanic ash from these eruptions can still be 
seen on the glaciers of the mountain peaks 
8-10 miles distant". 



UNITED STATES OF AMERICA 

STANDING COMMITTEE MEMBERS 

Mr. Charles G. Johnson, Assistant Chief, 
Military Geology Branch, United States 
Geological, Department of the Interior, 
Washington 25, D.C. 

Dr. Roger Revelle, Director Scripps Institu- 
tion of Oceanography, University of 
California, La Jolla, California. 

Dr. Donald E. White, United States Geolo- 
gical Survey, 4 Homewood Place, Menlo 
Park, California. 

PACIFIC INVESTIGATIONS 

The following notes have been prepared from 
a summary by Charles G. Johnson of U.S. 
Geological Survey activities in the Pacific since 
the 8th Pacific Science Congress in 1953. Most 
projects have been co-operative with other 
Government agencies, chiefly the Corps of 
Engineers, U.S. Army, Office of Naval Research, 
U.S. Navy, and U.S. Trust Territory of the Paci- 
fic Islands. 

Systematic geologic mapping was completed 
for Guam and Pagan in the Marianas, Truk in 
the Carolines, and Ishigaki and Miyako in the 
Ryukyus, and in addition the soils were concur- 
rently mapped on Guam, Ishigaki and Miyako. 
Soil mapping on Yap, in the Carolines, was 
also completed, geology having been previously 
mapped. 

Topical studies have continued on several 
islands, covering a variety of subjects, and provid- 
ing significant contributions to the knowledge of 
the structure and geologic history of the western 
north Pacific. U.S.G.S. Professional Paper 260 
A-R has appeared as the first 18 chapters on the 
geology, oceanography, geophysics and paleon- 
tology of the atolls Bikini, Eniwetok, Rongelap, 
Rongerik, and Aihnginae, studied by a large 
group of investigators during Operation Cross- 
roads. Four others (additional seismic studies, 
chemical erosion of beach rock, geothermal 
gradient, and fossil Foraminifera) are now in 
press proof, and several additional chapters are 
nearing completion. These deal mainly with 
results of deep drilling carried on at Eniwetok 
during 1951-52. A study of four species of 
fossil land shells recovered from drill-holes on 
Bikini, Eniwetok and Funafuti was completed, 
and geothermal measurements in the deep drill- 
hole on Eniwetok are being continued in an effort 
to detect rate of change of heat flow with time. 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



U.S.G.S. Professional Paper 280 A-K is also 
under way as a similar project on Saipan. Chap- 
ter A on the geology has been published, and the 
succeeding ones will deal with the soils, petro- 
logy, and petrography of the volcanic rocks and 
limestones, calcareous algae, microfossils, echi- 
noids, and submarine topography and shoalwater 
ecology. 

From Okinawa, studies of fossil brachiopods 
and mollusks have been completed, and work 
continues on the microfossils in cuttings from 
deep holes drilled during World War II. A long 
term study of fossil mollusks from several island 
groups including the Marshalls, Marianas and 
Palau is continuing. 

A petrologic study of the major soils of Guam 
was completed, including rapid chemical analyses, 
grain size distribution, pH, organic carbon, free 
iron oxide, mineralogic composition of sand-size 
material, and X-ray examination of silt and 
clay-size material. The limestones of Guam 
were examined by X-ray and microscope, and 
the beach sands and soils of the northern 
Marshall Islands were studied with respect to 
particle size distribution, mineral and trace 
element content, and relation of organic content 
to calcareous organisms that make up the bulk 
of the material. 

Large bulk samples of unweathered volcanic 
rock were collected from scattered islands for the 
purpose of gathering and comparing geochemical 
data throughout the Pacific and surrounding 
areas. Emphasis will be placed on problems of 
differentiation and the variation of minor ele- 
ments. 

Construction of a laboratory in Kilauea on 
Hawaii was started and should be completed by 
February, 1958. It will be equipped for mass- 
spectrographic, chemical and spectrochemical 
analysis of volcanic rocks and their weathered 
products. The aim is the study of chemical 
volcanology and weathering. Systematic analyses 
will be made of volcanic and solfataric gases 
and residual volatiles in lavas. A project on 
chemical weathering, principally on the devel- 
opment of laterites, is being started. 

In addition to carrying out research, the 
U.S.G.S. has aided Pacific countries by the 
training of professional personnel, the organiza- 
tion of geologic survey agencies, and the investiga- 
tion of mineral deposits and water resources. 
Countries that have received such aid are Thai- 

4 



land, Taiwan, Indonesia, South Korea and the 
Philippines. 

INTERNATIONAL GEOPHYSICAL YEAR 

Reviews of the United States program "oF 
geophysical endeavour for the IGY are published 
in Bulletins Nos. 1 and 2, issued by the National 
Academy of Sciences in the American Geophy- 
sical Union Transactions, Vol. 38. No. 4. The pro- 
gram is planned and directed by the U.S. National 
Committee for the international Geophysical 
Year, with the co-operation and assistance of 
hundreds of scientists and many public and 
private institutions. Outstanding in the list 
of public institutions are the National Science 
Foundation and the Department of Defense. 

In the Antarctic program, oceanographic 
observations were carried out during the 1955/56 
operations. Continuous echo soundings of the 
ocean bed were made south of Panama, and 
bathythermograph observations were made in the 
Pacific and across the Antarctic Convergence. 
Gravity and geomagnetic observations were 
also carried out. In the 1956/57 period the IGY 
stations of Little America, South Pole, Byrd, 
Ellsworth, Wilkcs and Adare were established 
and manned, and seismic, gravity and geomagne- 
tic observations were commenced. A seismic 
profile, begun 200 miles out from Little America, 
has shown that the ice depths increase from 
2,000 to 7,000 feet approaching the station. A 
profile in the immediate vicinity of the site has 
determined that this station, which is only 5,000 
feet above sea level, is located upon 10,000 feet 
of ice; these data must be regarded as tentative 
pending more detailed studies. 

Of interest also to Pacific science is the Arctic 
drift ice program, which called for the establish- 
ment of two stations on drifting sea-ice, to study 
the annual mass budget of the Arctic sea ice 
and its relation to total accumulation and 
ablation at the ice-ocean and ice-atmosphere 
interfaces respectively. 

Accumulation and ablation of the upper surface 
of the ice pack will be measured by the combined 
use of stakes to determine the rise or fall relative 
to a fixed reference plane within the ice floe, 
together with measurements of weight differences 
over given time periods, by the taking of vertical 
cores through the surface snow and ice. Accre- 
tion or ablation of ice at the bottom of the ice 
pack will be determined from a series of cores 
taken through the ice pack every two or three 
months. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Oceanographic data will be gathered on current 
flow, temperature and salinity at different depths; 
age determinations will be made on water samples 
taken from various depths; bottom cores will be 
taken to permit comparison of Arctic Ocean 
sedimentation, stratigraphy and marine life with 
that in other oceans. 

The earth satellite program may throw light 
on the distribution of the earth's. mass and possi- 
bly even the composition of its crust from 
observed perturbations in the satellite's orbit, 
provided the orbit is precisely known. It can 
also obtain synoptic data on the earth's magnetic 
field in space. 

The seismological program includes, in addi- 
tion to work on the thickness of the ice sheet in 
the Antarctic, the study of crustal structure there 
by seismographs, and seismic exploration will be 
carried on in the southeast Pacific by the Scripps 
Institution of Oceanography. 

Simultaneous land and sea measurements are 
involved in the program of seismic exploration of 
coastal structures. In addition, measurements 
in sharply contrasting terrain very high moun- 
tains and neighboring lowlands will be carried 
on in the Andes. A crustal strain seismograph 
has been installed in Santiago, Chile, and a 
second installation is practically complete at 
Huancayo Geophysical Observatory, Peru, con- 
structed and installed under the supervision of 
Hugo Benioff, California Institute of Technology. 
These will be used to collect data on the ac- 
cumulation of strain, whose release causes earth- 
quakes. 

Data on long period and other surface seismic 
waves will be collected by a widespread network 
of instruments. One long period instrument is 
now installed at the Coast and Geodetic Survey 
Seismological Observatory in Honolulu, and 
instruments have been shipped to the Belgian 
Congo and Trinidad. Nine additional installa- 
tions are scheduled. 

In the Arctic and North Atlantic Ocean regions, 
as well as several western Pacific islands, the 
U.S. Coast and Geodetic Survey will conduct 
studies of wave velocities, the location of earth- 
quakes, crustal structure, and the relation of 
microseisms to storms. Pacific stations are at 
Guam, Truk and Koro. A seismograph is being 
installed at Palmyra Island in cooperation with 
Scripps Institution of Oceanography. 

For a discussion on Antarctic Seismology, 
reference may be made to an article of that 
title by Frank Press in Engineering and Science 



Monthly, June 1957, published at the California 
Institute of Technology. 

The gravity programme basically includes an 
extension of the existing network of pendulum 
base stations and gravimeter measurements 
extending from them, especially in the southern 
hemisphere and polar regions. The program 
calls also for improved determination of the 
rigidity of the earth at the tidal periods of approx- 
imately 12 and 24 hours. A highly sensitive 
gravimeter has been designed for this, and Louis 
B. Schlichter, Director of the Institute of Geo- 
physics, Univeristy of California, who helped to 
develop it, recorded a maximum amplitude of 
tidal motion of the earth of about four inches in 
November 1956 in Honolulu. Submarine gravity 
measurements are also projected. 

In oceanography, sea-level stations have been 
installed in the Pacific by Scripps Institution of 
Oceanography at Marcus, Pitcairn, Rurutu, 
Canton, Johnston, Wake and Napuka island, 
and others are being equipped. Many island 
observatories will also observe ocean temperature 
and salinity to depths of 1,000 ft. to help deter- 
mine to what extent changes in sea level are owing 
to volumetric changes, and to what extent they 
are caused by movements of water mass. Equip- 
ment at many stations will record various waves 
of 5- to 15-minute duration. Deep-water ship 
operations will study deep circulation, and 
bottom topography and composition. A com- 
prehensive study of the amount of COi in the 
atmosphere and ocean will establish bench marks 
for future trends. 

HAWAIIAN VOLCANO OBSERVATORY 

A brief eruption of Kilauea Volcano occurred 
from 31st May to 3rd June, 1954. This has been 
described by Macdonald and Eaton (Volcano 
Letter No. 524, 1954). The volcano continued 
in an uneasy state, until finally in late February, 
1955, earthquake activity increased greatly and 
centred in eastern Puna, where an eruption 
commenced on February 28. It continued inter- 
mittently until May 26, when it ceased suddently. 
This was the first flank eruption of Kilauea since 
1923, and the first in the eastern Puna district 
since 1840. 

The eruption was described by Macdonald 
and Eaton (Volcano Letter No. 529 & 530, 1955). 
Of special interest was the observation and photo- 
graphing for the first time in history the complete 
sequence of the development of new volcanic 
vents. 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



"First, hairline cracks opened in the ground, 
gradually widening to 2 or 3 inches. Then from 
the crack there poured out a cloud of white, 
choking sulfur dioxide fume. This was followed 
a few minutes later by the ejection of scattered 
tiny fragments of red hot lava, and then the 
appearance at the surface of a small bulb of viscous 
molten lava. The bulb gradually swelled to a 
diameter of 1 to 1.5 feet, and started to spread 
laterally to form a lava flow. From the top of 
the bulb there developed a fountain of molten 
lava which gradually built around itself a cone 
of solidified spatter. The same general sequence 
was observed at three separate points during 
the day" (p. 6). 

A temperature of close to 2000F was measured 
in a lava fountain, but in a pit near the Kalapana 
Road a temperature estimated to be at least 100F 
higher was noted, and the walls were seen to be 
covered by stalactites formed by fusion of the 
old rock under the intense heat of the burning 
gas. 

The account also includes graphical represen- 
tation and discussion of the relations between 
tilt, tremor and strain release index of earth- 
quakes before and during this eruption. 

"Publication of the Volcano Letter will be 
discontinued with this issue. Beginning in 
January, 1956, the quarterly report of the 
Hawaiian Volcano Observatory will be published 
by the United States Geological Survey." With 
this brief notice in the Volcano Letter No. 529 
& 530 the world's best known volcano publication 
came to an end, when its publication by the 
University of Hawaii ceased. Simultaneously 
Dr. G.A. Macdonald severed a long connec- 
tion with the Observatory, and Dr. J.P. Eaton 
was appointed Director in his place. Quarterly 
accounts of observations are now published in 
the Hawaiian Volcano Observatory Summary, 
of which Nos. 1 to 4 have already appeared. 

Publications of particular interest since 1953 
are: 

Wentworth, C.K. and Macdonald, G.A., 1954, 
Structures and Forms of Basaltic Rocks 
in Hawaii. U.S.G.S. Bull 994. 

Wentworth, C.K., 1954, The Physical Benavi- 
our of Basaltic Lava Flows. Jour. Geol. 
62:425-438. 

Macdonald, G.A. and Eaton, J.P, 1955, Ha- 
waiian Volcanoes during 1953. U.S.G.S. 
Bull. 1021-D. 

Macdonald, G.A., 1954, Activity of Hawaiian 



Volcanoes during the years 1940-1950. 
Bull. Vole. Ser. //, 15: 119-179. 

, 1956, The structure of Hawaiian 
Volcanoes. Reprint from the Gedenk- 
boek H.A. Brouwer. Verh. Kon. Ned. 
Geol. Mynb. Gen. 16:1956. 

Richards, A.F., 1954, Volcanic eruptions of 
1953 and 1948 on Isabela Island, 
Galapagos Islands, Ecuador. Volcano 
Letter 525: 1 -3. 

McBirney, A.R., 1955, Recent volcanic activity 
in Central America. Volcano Letter 
527:1-2. 

, 1956, The Nicaraguan Volcano 

Massaya and its caldera. Trans. Am. 
Geophys. Un. 36: 1-2. 

Bullard, F.M., 1956, Volcanic activity in Costa 
Rica and Nicaragua in 1954. Trans. 
Am. Geophys. Un. 37:75-82. 

Juhle, W. and Coulter, H., 1955, The Mt. 
Spurr eruption, July 9, 1953. Trans. Am. 
Geophys. Un. 36:199-202. 

(This includes an account of a flash flood 
caused by torrential rain accompanying the 
eruption in the vicinity of the volcano. Gorges 
normally carrying water 1 ft. to 2 ft. deep were 
filled to 40 ft. to 50 ft. with a flood carrying 
boulders, ice and debris that blocked the 
Chakachatna River and formed a lake 5 miles 
long). 

GEOPHYSICS 

A report of the Special Committee of the 
American Geophysical Union on the geophysical 
and geological study of continents (G.P. Wool- 
lard, Chairman, A.G.U. 36, 695-708, 1955) 
includes mention of gravity, radioactive, geo- 
thermal, magnetic, electrical and tectonic studies 
of the American continent, and references to 
published work. Thicknesses of the crust are 
quoted for 21 localities, and range from 19 km. 
to 38 km. 

Gutenberg (Verschiebung der Kontinente, 
Eine kritische Betrachtung. Geotektonisches 
Symposium zu Ehren von Hans Stille, Stuttgart, 
1956.) reviewed evidence for horizontal displace- 
ments of land masses at a speed roughly 1 mile in 
100,000 years in recent geological time, and states 
that the viscosity is not too great to permit appa- 
rent polar movements by wandering of conti- 
nental blocks 100 kms. thick. He also pointed out 
that if the Mohorovicic discontinuity is due to a 



phase change, then appreciable changes in its 
depth could be expected where the temperature 
beneath the crust is changing by even small 
amounts. 

Benioff (Orogenesis and deep crustal struc- 
ture-additional evidence from seismology. B.C. 
S.A. 65, 385-400, 1954) has studied the seismic 
evidence from eight orogenic regions, and deter- 
mined that the structures responsible for the 
great linear and curvilinear mountain ranges 
and oceanic trenches are complex reverse faults. 
He has classified them into two types oceanic 
and marginal. Oceanic faults, typified by the 
Mindanao, Tonga and Kermadec structures, 
have an average dip of 61, and two components 
extending from the ocean bottom to 60 km. 
and from there down to 700 km. Marginal 
faults, typified by the New Hebrides, Aleutian, 
Sunda, Kurile- Kamchatka, Peru- Ecuador and 
other structures, have shallow and intermediate 
members extending with an average dip of 33 to 
60 km. and 300 km. respectively, and a third 
component with dip of 60 extending down to 
650 km. The elastic-strain rebound character- 
istics of the marginal faults show that the three 
components move as separate units. 

He also offered a hypothesis for the origin of 
the volcanoes associated with these structures, 
by assuming that the inelastic components of the 
repeated to-and-fro strains involved in the 
generation of the sequences of earthquakes and 
after-shocks generate heat. Tn the case of South 
America he calculated that roughly 10 23 ergs 
per year is the amount of energy liberated. 
(Benioff stated that he did not know if this would 
be equivalent to the volcanic energy required to 
maintain the South American system of volca- 
noes. It is for example about half of the energy 
released by natural thermal activity at Wairakei 
hot springs, New Zealand, and is thus a small 
fraction of New Zealand's discharge of volcanic 
energy. J. Healy). 

Progress reports of the Seismological Labora- 
tory of the California Institute of Technology 
have been published in the Transactions of the 
American Geophysical Union. They contain 
complete lists of publications. Reports are as 
follows :- 



1953. A.G.U. 35, 

1954. A.G.U. 36, 

1955. A.G.U. 37, 

1956. A.G.U. 38, 



979-987, 1954. 

713-718, 1955. 

232 - 238, 1956. 

248 - 254, 1957. 



OCEANOGRAPHY 
At the 8th Congress R.S. Dietz presented a 



WLJLJME J2 GEOLOGY AND GEOPHYSICS 

paper on the marine geology of the northwestern 
Pacific, based on the Japanese Bathymetric 
Chart 6901 . The paper has now been published 
(Dietz, 1954), and is another important addition 
to the growing list of literature describing the 
hidden morphology of the Pacific basin. The 
Structural features of this large fraction of the 
earth's surface are gradually being pieced to- 
gether. The echograms obtained on the Scripps 
Institution U.S. Navy Mid-Pacific Expedition 
of 1950 have been published by Dietz, Menard 
and Hamilton (1954). This expedition obtained 
data continuously between San Diego and the 
Marshall Islands, and considerable new informa- 
tion was obtained. 

The Hawaiian Islands are located on a broad 
swell bounded by a trough and an arch believed 
to be formed by crustal yielding due to the weight 
of the Hawaiian Ridge. Between Hawaii and the 
Marshall Islands is a mountainous region termed 
the Mid-Pacific Mountains. It includes guyots, 
and from the mile-deep top of two of them were 
dredged Cretaceous reef fossils. The Medocino 
escarpment was crossed at several places. Much 
of the sea floor is rough, but there are flat basins, 
and it seems necessary to assume the existence of 
currents along the sea floor to explain the erosion 
and existence of currents along the sea floor to 
explain the erosion and redistribution of sedi- 
ment once it has been deposited. 

Menard (1955) has summarized information 
on the bathymetry of the north-eastern Pacific 
basin, where four great fracture zones trending 
east and west for distances ranging from 1400 to 
3300 miles in length are now known. He has 
tentatively ascribed their formation to plastic, 
deformation of the crust because of stress induced 
by an annular convection current that rises near 
the Hawaiian Islands and sinks near North 
America. Associated with the fracture zones are 
large numbers of guyots, some of which at least 
are known to be volcanic. 

A detailed account by Hamilton (1956) of the 
guyots of the Mid-Paciflc Mountains investigated 
in the 1950 Mid-Pacific Expedition has been 
published by the Geological Society of America. 
Five of the flat-topped seamounts at depths of 
700 to 900 fathoms are described in detail. The 
Mid-Pacific Mountains are interpreted as a series 
of basaltic ridges and volcanoes formed by the 
extrusion of basalt on a broad swell, similar to the 
present Hawaiian structure. The ridges and 
volcanoes were planed off and sank beneath the 
sea during the Cretaceous. To account for this, 
subsidence of the Pacific basin in the area of the 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Mid-Pacific Mountains is favoured, preferably 
by the action of subcrustal convection currents, 
but possibly by foundering due to the weight of 
the mountains themselves. 

Menard has discussed (1955, 1956) some details 
of seabottom topography in relation to sedi- 
mentation. In particular he has described archi- 
pelagic aprons surrounding groups of existing 
or drowned islands. These are believed to be 
accumulations at least 1000 ft thick of submarine 
lava flows and ash. 

Dietz, R.S., 1954, Marine geology of North- 
western Pacific: Description of Japan- 
ese Bathymetric Chart 6901. B.G.S. 
Am. 56: 119-1224. 

Dietz, R. S., Menard, H. W. and Hamilton, 
E. L., 1954, Echograms of the Mid- 
Pacific Expedition. Deep-Sea Res. 1: 
258-272. 

Hamilton, E.L., 1956, Sunken islands of the 
Mid-Pacific Mountains. Geol. Soc. Am. 
Mem. 64. 

Menard, H.W., 1955, Deformation of the 
Northeastern Pacific Basin and the 
West Coast of North America. B.G.S. 
Am. 66: 1149-1198. 

1955, Fractures in the Pacific Floor. 
Scientific American, 193: 36-41. 

1955, Deep-sea channels, topography 
and sedimentation. Bull. Am. Ass. Pet. 
Geol. 39: 236-255. 

1956, Archipelagic aprons. Bull. Am. 
Ass. Pet. Geol. 40: 2195-2210. 

VOLCANOLOGY (1954-1957, information supplied 
by Dr. Donald E. White) 

The work of Bullard and his associates 
(reviewed in Bullard, Maxwell, and Revelle, 
1956) indicates that the heat flow in the ocean 
basin is at least as high as average heat flow in the 
continents in spite of the much greater thickness 
of matter of relatively high radioactivity under 
the continents. This work is with little doubt 
most significant to an understanding of the 
crust and mantle of the earth and to the ultimate 
causes of volcanism. 

A review of basaltic provinces (Green and 
Poidervaart, 1955) in space and time concludes: 
1) The bulk of oceanic basalts are unsaturated 
in silica; 2) There is no consistent variation in, 
composition with time; 3) There are no distinct 
types of basaltic magma but rather a continuous 
series from silica-saturated (tholeiitic) to silica- 
8 



unsaturated (olivine basaltic) rocks. This seems 
in accord with origin by partial melting of the 
upper mantle. 

Nockolds (1954) has revised the averages of 
chemical compositions of the major types of 
igneous rocks, based on modern analyses. 

Williams (1954) has reviewed problems and 
progress in volcanology and Waters (1955) 
suggests an explanation for the origin and inter- 
relationships of plateau basalts, the andesites and 
batholithic rocks of mountain belts, serpentines 
and amphibolites. 

Many papers discuss detailed relations of 
volcanic rocks of specific areas, and a few are 
concerned with compositions of fumarolic gases 
and condensates. 

HOT SPRINGS 

Important progress has been made on the 
problems of the content of volcanic water, and 
heat supply of hot springs closely associated 
with volcanism. It has been long suspected that 
meteoric water was dominant in these mixtures. 
This view is definitely confirmed by stable isotopes 
(Craig, Boato, and White, 1956). Isotopic frac- 
tionation from evaporation and precipitation 
causes major and easily detected differences in 
the stable isotopes of meteoric water. The iso- 
topes of each volcanic hot springs area so far 
investigated are closely related to the meteoric 
water of that particular area. No volcanic 
contribution has been positively identified: iso- 
topic relations suggest that the upper limit of 
volcanic water is not more than about 5 percent. 
If true, most of the heat must be supplied by 
rock conduction from the magma. 

Due to recent work, the Wairakei area in 

New Zealand is the most thoroughly studied 

thermal area in the world (See under New 
Zealand section). 

White (195 la) has attempted to explain the 
origins of the greatly differing compositions 
of thermal waters that are commonly closely 
associated with each other in areas of recent or 
active volcanism. He emphasizes physical envi- 
ronment of the emanations. The sodium chloride 
type is believed to result from condensation at 
considerable depth by meteoric water of emana- 
tions with nonvolatile substances in solution in 
a dense vapor phase. Most other types of water 
are believed to evolve from the sodium chloride 
type. In an accompanying paper (White, 1957b) 
volcanic waters of the sodium chloride type are 
compared with waters of connate and of possible 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



metamorphic origin. Tentative chemical and 
isotopic criteria are suggested to distinguish these 
waters. 

G.A. Waring has completed a bibliographic 
summary of the thermal springs of the world. 
This will be published in the near future by the 
U.S. Geological Survey. 

Many individual thermal spring areas have 
been studied in detail, and much attention has 
been given to the geochemistry of specific com- 
ponents. 

REFERENCES 

Bullard, E. C, Maxwell, A. E. and Revelle, 
R., 1956, Heat flow through the deep 
sea floor, p. 153-181 in H.E. Landsberg 
(Editor), Advances in geophysics, 3: 
p. 1-378, New York: Academic Press, 
Inc. 

Craig, H., Boato, G. and White, D. E., 1956, 
Isotopic geochemistry of thermal waters. 
Nat. Research Council Nuclear Set. 
Ser., Rept. No. 19, Nuclear processes 
in geologic setting, p. 29-44. 

Green, J. and Poldervaart, A., 1955, Some 
basaltic provinces, Geochim. et Cosmo- 
chim. Ada, 7: p. 177-188. 

Nockolds, S.R., 1954, Average ehemical com- 
positions of some igneous rocks Geol. 
Soc. Am. Bull., 65: p. 1007-1032. 

Waters, A.C., 1955, Volcanic rocks and the 
tectonic cycle. Geol. Soc. Am., Sp. 
Paper 62: p. 703-722. 

White, D.E., 1957a, Thermal waters of volcanic 
origin. Geol. Soc. Am. Bull., 68: Nov. 
, 1957b, Magmatic, connate, and meta- 
morphic wates. Geol. Soc. Am. Bull., 
68: Nov. 

Williams H., 1954, Problems and progress in 
volcanology. Quat. Jour. Geol. Soc. 
London, 109: p. 311-332. 

NEW ZEALAND 

STANDING COMMITTEE MEMBERS 

Mr. J. Healy, Geological Survey, Box 499, 
Rotorua. 

Professor R.S. Allan, Canterbury University, 
Christchurch. 

Reference to bibliographic publications has 
already been made in the early part of this report. 
A list of all geological publications on New 



Zealand is prepared annually and published in 
the Journal of Science and Technology. As from 
the end of 1957, the present form of the Journal 
will be changed, and geological and geophysical 
papers will be published in the N.Z. Journal of 
Geology and Geophysics. 

GEOLOGICAL MAPS 

To replace the existing 1:1,000,000 geological 
map of New Zealand an improved map on a 
scale of 1 :2,000,000 has been assembled and is 
now being prepared for publication. 

A new project has been commenced to map 
New Zealand on a scale of 4 miles to an inch by 
the end of 1962. For this purpose New Zealand 
has been divided into 28 sheets, and a schedule has 
been prepared. The first maps will appear in 
1958. 

QUATERNARY RESEARCH 

The last few years has seen an increasing 
interest in Quaternary geology, culminating in a 
special conference held by the Geological 
Survey in 1957 to discuss this subject alone. In- 
terest was probably sparked by Fleming (1953) 
by his comprehensive account of the Pliocene 
and Pleistocene geology of the Wanganui dis- 
trict. Current investigations arc proceeding on 
sea-level changes, glaciation, peri-glacial features, 
and volcanic ash shower chronology. 

The correlation problem, which has been the 
greatest one hampering progress in Quaternary 
research is now being in part at least overcome. 
Dating by C 14 now covers the range back to 
40,000 years, and Geological Survey holds records 
for 112 samples dated by this method. Of 
these most results have already been published by 
Fergusson and Rafter. Paleontology is still the 
basis of dating earlier events, though recently 
work has commenced on pollen study, and it is 
hoped that this will greatly improve correlation 
and climate study, especially in the late middle 
Pleistocene. 

Recent papers of particular interest are as 
follows : 

Brodie, J. W., 1957, Late Pleistocene beds, 
Wellington Peninsula. N.Z. Jour. Sci. 
Tech. 36B: 632-643. 

Cotton, C.A. and Te Punga, M.T., 1955, Soli- 
fluxion and periglacially modified land- 
forms in Wellington, New Zealand. 
Trans. Roy. Soc. N.Z. 82: 1-1031. 

9 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Couper, R.A. and McQueen, R., 1954, Pliocene 
and Pleistocene plant fossils of New 
Zealand and their climatic interpreta- 
tion. N.Z. Jour. Sd. Tech. 35B: 
398-420. 

Fleming C.A., \ 953, The Geology of the Wanga- 
nui Subdivision. N.Z.Geol Surv. Bull. 52. 

1955, Quaternary Geochronology in 

New Zealand. Act. IV Cong. Int. Quat. 
7953:925-930. 

Gage, M., 1953, The study of Quaternary 
strandlines in New Zealand. Trans. Roy. 
Soc. N.Z., 81 : 27-34. 

Stevens, G.R., 1957, Solifluxion phenomena 
in the Lower Hutt Valley. N.Z. Jour. 
Sci. Tech. 38B : 279-296. 

Brothers, R.N., 1954, The relative Pleistocene 
chronology of the South Kaipara dis- 
trict, New Zealand. Trans. Rov. Soc. 
N.Z. 82 : 677-694. 

Fergusson, G.J. and Rafter, T.A. ; New Zealand 

C 14 age measurements. 
1. N.Z. Jour. Sci. Tech. 35B, 127-8, 1953. 
2. N.Z. Jour. Sci. Tech. 36B, 371-374, 1955. 
3. N.Z. Jour. Sci. Tech. 38B, 732-749, 1957. 

GEOTHERMAL INVESTIGATIONS 

A power station to generate 69,000 KW of 
electricity from geothermal steam is now under 
construction at Wairakei, and an increase to 
151,000 KW is planned to use steam already in 
production. 

Since the last Congress drilling at Wairakei has 
been for production only. Geological work was 
concentrated on the mapping of fault traces on 
aerial photographs, and four were identified that 
seem to be important feeding fissures in the- 
Wairakei thermal area (Grindley, 1957). Fair 
success has been obtained by drilling to intersect 
these steeply-dipping fissures at about 2,000 ft. 
depth from the surface, and the best production 
wells in the fissured zones discharge about 80,000 
Ib of steam and 500,000 Ib of water per hour at 
a well-head pressure of 200 Ib/sq in. 

Some wells have shown a gradual decline in 
production, and in some cases at least this seems 
to be due to deposition of minerals, chiefly calcium 
carbonate, in the wells, which return to full 
production when drilled out again. 

Geophysical work at Wairakei has included 
a detailed temperature survey, using thermo- 
couple probes to a depth of 3 ft. as well as in 

10 



deeper drilled holes, to determine the full extent 
of the warm area, its surface thermal pattern and 
relation to geological structure. Results of this 
survey are not yet available. 

Chemical work on the well discharges has been 
continued and extended, and a research project 
on high temperature chemical equilibria in 
volcanic gases and steam (Ellis, 1957) was 
commenced. 

At Waiotapu, thermal area some 30 miles 
north-east from Wairakei, another investigation 
is under way. Geophysical work was done some 
time ago, but a detailed temperature survey, 
combined with drilling and geological and hot 
spring surveys, is now being completed. 

The following comments on geothermal inves- 
tigations are supplied by Mr. C.J. Ban well, of 
Dominion Physical Laboratory, N.Z. Dept. of 
Scientific and Industrial Research. 

"In the course of an intensive drilling program 
for power production, approximately 50 holes 
have been drilled in an area measuring roughly 
1^ miles by \ mile. One of these holes has 
reached a depth of approx. 1 kilometre, and 
most of the more recent holes have depths of 
600 to 700 metres. Practically all the holes 
produce a mixture of steam and water in propor- 
tions corresponding rather closely with the tem- 
peratures measured in their lower sections. The 
physical and geological data obtained from these 
holes are consistent with the idea that the region 
tapped by them, consisting largely of permeable 
volcanic breccias, is fed by hot water at a tempera- 
ture of about 260C rising through joints or 
fissures in a much less permeable formation 
which underlies most of the area so far explored 
at a depth of the order of 600-700 metres. No 
hole has yet been drilled deep enough to reach 
the bottom of this impermeable formation (an 
ignimbrite), which must have a minimum thick- 
ness of some 300 metres, and there is little 
evidence available to indicate what its true thick- 
ness may be. Some of the holes drilled into it 
have shown temperatures falling with depth in 
their lower sections, suggesting that the regions 
beneath are not uniformly hot, but apart from 
this, not very much can be said about the nature 
of the hot fluid below the ignimbrite; it could 
equally well be steam or hot water. An attempt 
is being made to drill into one of the supposed 
feeding fissures at some depth in the ignimbrite, 
and if this is successful, much new information 
about the mode of heat transfer through this 
formation, and the hot fluid below, should be 
obtained. 



VOLUME 12 



Regarding the origin and mode of transfer of 
heat at still greater depths, Ban well (1957) has 
discussed some of the physical implications of 
heat transfer models involving either convection 
(by steam and magmatic gases) or conduction 
(from a mass of hot rock to circulating ground 
water) and discussed some of the theoretical 
difficulties associated with a simple conductive 
model. However, the results of recently pub- 
lished work with stable isotopes 'in other thermal 
areas (Craig, Boato and White, U.S.A.) indicate 
such small proportions of primary (magmatic) 
gases, including water, that the initial tempera- 
ture of these gases would need to be improbably 
high if they were responsible for most of the ini- 
tial heat transfer. Although not a great deal of 
this kind of isotope work has so far been done at 
Wairakei, the results of some preliminary obser- 
vations of Carbon 14 content, based on a greatly 
improved technique for the determination of this 
isotope, indicate that both the emissions of the 
White Island 1 fumaroles and some of the natural 
steam vents at Wairakei must contain a major 
proportion of water of surface origin (G.J. 
Fergusson, pers. comm.). Thus, it would appear 
that some kind of conductive process must be 
called upon to provide much of the observed heat 
transfer, and the devising of physically workable 
and geologically acceptable conductive models 
offers some interesting problems." 

Recent publications of geological interest on 
geothermal investigations are as follows > 

Hamilton, W.M., 1954, Geothermal energy. 
Cawthron Lecture Series r , No. 27. 

Grange, L.I. (compiled by), 1955, Geothermal 
steam for power in New Zealand. 
N.Z.D.S.I.R. Bull. 117. 

Ellis, A.J. and Wilson, S.H., 1955, The heat 
from the Wairakei-Taupo thermal 
region calculated from the chloride 
output. N.Z. Jour. Sci. Tech. 36B: 
622-631. 

Steiner, A., 1955, Wairakite, the calcium 
analogue of analcime, a new zeolite 
mineral. Min. Mag. 30: 691. 

Coombs, D.S., 1955, X-ray observations on 
Wairakite and noncubic analcime. 
Min. Mag. 30: 699. 

Healy, J., 1956, Preliminary account of hydro- 
thermal conditions at Wairakei, New 
Zealand. Proc. 8th Pac. Sci. Cong. 
II, 214-227. 



GEOLOGY AND GEOPHYSICS 

Grindley, G.W., 1957, Geothermal power. 
Science in New Zealand, Ed. F.R. 
Callaghan, 112-122. 

Banwell, C.J., 1957, The New Zealand thermal 
area and its development for power 
production. Trans. A.S.M.E., 79:255. 

Studt, F.E., 1957, Wairakei hydrotherma) 
system and the influence of ground 
water. N.Z. Jour. Sci. Tech. 38B : 
595-622. 

Ellis, A.J., 1957, Chemical equilibrium in mag- 
matic gases. ^/?7. Jour. Sci. 255:416- 
431. 

STRATIGRAPHIC LEXICON 

The preparation of material for the New 
Zealand section of the international stratigraphic 
lexicon by New Zealand geologists has been 
completed, and the huge task of editing and 
preparing this for publication, undertaken by 
Dr. C.A. Fleming, is almost finished. Its pre- 
paration was in the first place considerably 
simplified by the earlier appearance of the 
Bibliographic Index of New Zealand Stratigraphic 
Names by G.L. Adkin (N.Z.G.S. Mem. 9, 1954), 
but the greatly increased scope of the Lexicon will 
make it an invaluable asset to New Zealand 
geology. 

GEOLOGICAL STRUCTURE 

H.W. Wellman, 1956. Structural outline of 
New Zealand. N.Z. D.S.I. R. Bull. 121. 

This bulletin is a concise statement of the 
dominant structural features of New Zealand. 
For this purpose New Zealand has been divided 
into 20 structural regions based on natural 
divisions. Each is described separately, and in 
addition there is an account of the rocks of 
New Zealand and their structures in period 
groups. The Bulletin is accompanied by five 
maps and 151 references. 

INTERNATIONAL GEOPHYSICAL YEAR 

Preliminary organization of New Zealand's 
effort for the I.G.Y. was by a National Committee 
of the Royal Society of New Zealand, but for 
the co-ordination and execution of the program 
an Interdepartmental Committee was formed. 

Geomagnetic work will include observations 
of the earth's magnetic field at stations in New 
Zealand, Rarotonga, Samoa, Campbell Island, 



i White Island is the top of a large and mostly submerged volcanic mass located in the Bay of Plenty about 100 miles 
NE of Wairakei. 

11 



PROCEEDINGS Ol THE NINTH PACIFIC SCIENCE CONGRESS 



and Cape Adare and Scott Base, McMurdo 
Sound. Earth currents will be observed along 
two lines near Christchurch. 

In glaciology, geological work is already in 
hand for the measurements of shrinkage and 
movement on the Tasman and Franz Josef 
glaciers. In the Antarctic the New Zealand 
parly will make gravity and seismic surveys of 
ice thickness up to and on the polar plateau 
between McMurdo Sound and the South Pole. 

The oceanographic program includes the 
installation and operation of tide gauges in 
New Zealand and outlying islands, the operation 
of a long wave recorder at North Cape, and ocean 
measurements at stations in the South Pacific 
and Southern oceans. 

For studies in seismology, instrumentation in 
New Zealand and Samoa have been improved, 
and new stations have been established at 
Raoul Island, Scott Base and Adare (with the 
Americans). A better understanding of the 
seismicity of a much larger and partly unknown 
area is sought. 

Gravity measurements will be extended from 
a new base at Scott Base, McMurdo Sound, in 
the Ross Sea Dependency and inland towards 
the South Pole. 

PACIFIC ISLANDS 

Assistance has been given to various Pacific 
islands. Geological surveys have been made at 
Niue, Samoa and the Cook Islands, and a survey 
of hot springs to assess geothermal potential in 
Fiji was carried out. 

SEISMOLOGY 

The continuous recording and analysis of 
earthquake data has been continued, with special 
attention to various aspects of New Zealand" 
earthquakes. A special project of interest has 
been the crustal studies in the Wellington area. 
These have now been extended into the Auck- 
land area, and other work is planned. 

Eiby, G.A. and Dibble, R.R., 1957, Crustal 
Structure Project. N.Z. D.S.l.R. Geo- 
physical Mem. 5. 

OCEANOGRAPHY 

The N.Z. Oceanographic Institute has carried 
out studies of Pleistocene and Recent sediments 
in Hawke Bay and elsewhere. A considerable 
amount has been done on the assembling informa- 
tion on the sea bottom round New Zealand, and 

12 



on the structural significance of the physical 
forms. A bibliography has been published 
of oceanographic work in New Zealand (Geo- 
physical Mem. 4, 1955), and there is an account 
of post-war oceanography in Science in New 
Zealand (Ed. F.R. Callaghan, 1957) by R.M. 
Cassie. 

AUSTRALIA 

STANDING COMMITTEE MEMBERS 

Dr. N.H. Fisher, Chief Geologist, Bureau of 
Mineral Resources, Geology and Geo- 
physics. Childers Street, Turner, Can- 
berra. 

Professor J.C. Jaeger, Research School of 
Physical Sciences, The Australian 
National University, Box 4, G.P.O., 
Canberra. 

VOLCANOLOGY 

The following information on volcanology is 
compiled from the 1954-56 report of the Sub- 
Comniittee on Volcanology, of the Australian 
Committee on Geodesy and Geophysics. 

Volcanological work was confined to the 
New Guinea area, including the Solomon Islands, 
and was carried out mainly from the Volcanolo- 
gical Observatory at Rabaul. M.A. Reynolds 
was officer in charge of the Observatory for most 
of the period under review. Field and aireal 
observations of other volcanoes were also 
carried. 

The observatory at Rabaul functioned conti- 
nuously. Instruments at the observatory are a 
three-component short period Benioff seismo- 
graph, and a two-component tiltmetcr. An 
Omori-type two component seismograph is main- 
tained at Rapindik, 5.5 km south-south-east of 
the observatory and 2.5 km west-north-west 
of Matupi volcano. The following reports are 
prepared regularly : 

Weekly : Provisional seismological Bulletin 
Monthly : Volcanological report 

: List of tremors reported to the 

Observatory 

Quarterly : Seismological Bulletins 
Irregularly : Reports on investigations of vol- 
canic centres, volcanic eruptions 
or seismic phenomean. 

Volcanic activity since January, 1954, has been 
summarized. 



Tuluman. Submarine activity at this "new" 
centre continued, and two small islands were 
built up above sea level, but their shape is 
continually changing, due to eruption and 
erosion. The lava is basaltic in composition. 

Bam. Mild explosive eruptions began on 3 
August 1954, and continued intermittently at 
intervals through 1955 and 1956. 

Manam. Ejections of dust began in December 
1956. Activity continued during January and 
February 1957 with explosive eruptions and 
extrusion of lava. 

Long Island. Eruptions from the island crater 
on Lake Wisdom continued intermittently from 
8 May 1953 till 7 January 1954. Further erup- 
tion, with the ejection of incandescent ash 
occurred from 5 to 13 June 1955. 

Langfla. After earlier premonitory signs, 
the more northerly crater burst into eruption on 
18 May 1954 and continued with intervals until 
June 1955, with a further period of mild eruptions 
towards the end of March 1956. 

Lamington. Dome building continued quietly 
at least until September 1956, with some breaking 
up and collapse of the upper part of the lava 
dome. An "explosion" was reported on 27 
March 1956. 

D"* Ent recast eaux Islands. Earthquake swarms 
were experienced in the area about Dobu, be- 
tween Fergusson and Norman by Islands, from 
July to September 1955, and again in the first 
months of 1957. In the intervening period 
earth tremors were more frequent than normal. 
Several craters exist in the area and are being 
kept under observation for possible volcanic 
eruption, though none has been recorded pre- 
viously. 

Savo. Local investigations established that 
this volcano is definitely of the Pelean type, so 
arrangements were made for the establishment of 
a system of warning of any increase in tempera- 
ture or local seismic activity. 

Tinakula (Santa Cruz Is.) This very active 
volcano is reported to have become quieter since 
1951. 

Yasour (Tanna). This volcano is continually 
active with small explosions from a pool of liquid 
lava in the bottom of the crater, but with excep- 
tionally violent activity in January 1956. 

Both G.A. Taylor and M.A. Reynolds have 
devoted a considerable amount of attention to 
research on the relationship between volcanic 
eruptions and seismic activity, and to the influ- 
ence of luni-solar factors on such activity. Petro- 



VOLUMEJ2 GEOLOGY ANDJ2EOPHYSICS 

logical examinations of lavas from the Melane- 
sian volcanic centres have been made in the 
laboratory at the Bureau of Mineral Resources, 
and 18 chemical analyses of rock types from Mt. 
Lamington were completed. 

Samples of burned wood from Rabaul, Long 
Island and Lamington were sent to New Zealand 
for C 14 dating. Recent publications are as 
follows :- 

Best, J.C., 1956, Investigations of recent volcanic 
activity in the territory of New Guinea. 
Proc. 8th Pac. Set. Cong. II, 180-204. 

Fisher, N.H., 1954, Report of the sub-Com- 
mittee on Vulcanology 1951. Bull. 
Vole. Ser. 77, 15: 71-79. 

Grover, J.C., 1955, Geology, Mineral deposits 
and prospects of mining development 
in the British Solomon Islands Protec- 
torate. Interim GcoL Surv. Sol. Is. 

Mem. 

Taylor, G.A., 1956, Report of the Sub-Com- 
mittee on Vulcanology 1953. Review 
of volcanic activity in the Territory 
of Papua-New Guinea, the Solomon 
and New Hebrides Islands, 1951-53. 
Bull. Vole. Ser. II 15: 81. 

Taylor, G.A., 1954, Vulcanological observations 
at Mt. Lamington 29th May 1952. 
Bull. Vole. Ser. 77, 15: 81-89. 

Taylor, G.A., 1956, An outline of Mt. Laming- 
ton eruption phenomena. Proc. 8th Pac. 
Sci. Cong. 77, 83-88. 

The following publications were in press or 
ready to go to the press at March, 1957. 

Fisher, N.H. Catalogue of the active volcanoes 
and solfatara fields of Melanesia. 
Part V of the Catalogue of the active 
volcanoes of the world edited by the 
International Volcanological Associa- 
tion. 

Grover, J.C. Interim Geol. Surv. Brit. Sol. Is. 

Mem. 2. 

Reynolds, M.A. and Best, J.C. The Tuluman 
volcano, St. Andrew Strait, Admiralty 
Islands, Bur. Min. Res. Aust. Bull. 38. 

Taylor G.A. The Mt. Lamington eruption of 
1951. Bur. Min. Res. Aust. Bull. 38. 

Taylor, G.A., Reynolds, M.A. and Best, J.C. 

Eruptive activity and associated pheno- 
mena, Mt. Langila, New Britain, 1952- 
1956. Bur. Min. Res. Aust. Rept. 26. 

13 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



INTERNATIONAL GEOPHYSICAL YEAR 

The Australian Academy of Science is the 
planning organization, but there is appointed 
an Australian National Committee for the 
International Geophysical Year, to co-ordinate 
the Australian projects. There are in addition 
sub-Committees to deal with individual aspects. 

Geomagnetic observations will include meas- 
urements of the earth's field, especially near the 
equator and in the auroral zones, and during 
magnetic storms. 

Ice depth determinations will be made and 
general glaciological investigations carried out 
on the Antarctic continent inland from Mawson. 

Ocean movements tides and long waves will 
be recorded at Norfolk Island and Willis Island, 
and tides will be recorded also at sites on the 
western shores of the Tasman and Coral Seas. 
Microscisms will be investigated on the Queens- 
land coast. 

The number of standard seismograph stations 
will be increased from two to seven in continental 
Australia, and others will operate at MacQuarie 
Island and Mawson. 

HYDROLOGY 

The Australian Academy has now established 
a Standing Committee for Hydrology, with 
convener Professor E. S. Hills of the University 
of Melbourne. This replaces the former sub- 
Committee for Hydrology of the National 
Committee for Geodesy and Geophysics. 

SEISMOLOGY 

The Report on Seismology in Australia, 1954- 
57, published by the Secretary of the Sub-Com- 
mittee on Seismology, contains a description of 
the active seismograph stations in Australia. ^ 

Under the aegis of Professor Jaeger, of the 
Australian National University, Canberra, and 
Professor Bullen, of the Department of Applied 
Mathematics, University of Sydney, new research 
is being carried on with a view to the revision of 
travel time-tables of near earthquakes in the 
Australian region. Some of the data used 
in this research have come from the study of 
seismograms of controlled explosion in the 
Snowy Mountain area. 

Research at stations under the control of the 
University of Queensland includes investigations 
into local tremors and into microseisms, with 
special references of the relation of these to 
cyclonic disturbances; investigations into the 

14 



direction of faulting; into the nature of the crust 
in the S.W. Pacific; theT-phase, as recorded at 
Brisbane. A study of L g from the New Guinea 
region has recently been initiated. 

At Canberra recent research includes deter- 
minations of the depth of the crustal layer, use 
being made of recordings of controlled explo- 
sions. 

At Riverview College, Sydney, investigations 
of teleseisms, with special reference to core 
phases, are carried out. Also research into local 
tremors, with a view to determining epicentres, 
so that a revision of travel-time-tables for near 
earthquakes may be possible. Recent research 
includes an investigation into the travel times of 
waves generated by "nuclear explosions". 

Recent investigations by the Bureau include 
determinations of crustal thickness, using data 
obtained from controlled explosions. The follow- 
ing bibliography ends the above report: 

Bolt, B.A., 1956, The Epicentre of the Adelai 
de Earthquake of 1954, March 1. J. and 
Proc. Roy. Soc. of N. S.W. 90 : 39-43. 

Bullen, K.E., 1954, Composition of the Earth's 
outer core. Nature 174 : 505. 

, 1954, Euler's equation and (p,r) 

coordinates. Math. Gazette 38 : 172-174. 

, 1954, Conversion of variation prob- 
lems into isoperimetrical problems. 
Math. Gazette 38 : 249-252. 

, 1954, On the homogeneity, or other- 
wise, of the Earth's upper mantle. 
Trans. Amer. Geophy. Vn. 35 : 838-841. 

, 1955, On the size of the strained 

region prior to an extreme earthquake. 
Bull. Seis. Soc. Amer. 45 : 43-46. 

, 1955, Note on New Zealand crustal 

structure. Trans. Rov. Soc. of N.Z. 
82 : 995-999. 

, 1955, Some trends in modern 

seismology. Science Progress, 170 : 
211-227. 

1955, Physical properties of the 
Earth's core. Ann. Geophys. 11 : 53-64. 

, 1955, The Interior of the Earth. 

Scientific American 193 : 56-61. 

, 1955, Proposal for the use of atom 

bombs for seismological purposes. 
Bull. cT Information de VV.G.G.L, 12 : 
550-552. 

, 1955, Features of seismic pP and 

PP rays. M.N. Roy. Astr. Soc., Geo- 
phys. Supp. 1 : 49-59. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Bullen, K.E., 1956, Seismic wave transmission. 
Encyclopedia of Physics 47 : 74-118. 

, 1956, Seismology and the broad 

structure of the Earth's interior. Phy- 
sics and Chemistry of the Earth 1 :68-93. 
Pergamon Press. 
., 1956, Seismology and the Earth's 



deep interior. Aust. J. Sci. 19 : 99-100. 
, 1956, The influence of the tempera- 
ture gradient and variation of com- 
position in the mantle on the computa- 
tion of density values in Earth Model 
A. M.N. Rov. Astr. Soc., Geophy. 
Supp.l :2\4-2\l. 

, 1956, Note on the phase PKJKP. 

Bull. Seism. Soc. ofAmer. 46 : 333-334. 

, _,1957, The International Geophysical 

Year. Australian Quarterly 29 : 16-25. 
Bullen, K.E. and Bolt, B.A., 1956, The South 
Australian Earthquake of 1939, March 
26. /. and Proc. Rov. Soc. of N.S. W. 
90 : 19-28. 

Burke-GafTney, T.N., 1954, The T-phase from 
the New Zealand Region. J, and Proc. 
Roy. Soc. of N.S. W. 88:50-54. 
Burke-GafTney, T.N. and Bullen, K.E., 1957, 
Seismological and related aspects of 
the 1954 Hydrogen Bomb explosions. 
Aust. J. of'Phys., 10:130-136. 
Kerr Grant, C, 1956, The Adelaide Earthquake 
of 1st March, 1954. Trans. Rov. Soc. 
of S.A. 79:177. 

Upton, P.S., 1956, Cyclone Microseisms at 
Brisbane. A new method of analysis. 
Bull. Dept. GeoL, Univ. of Queens., 
4:14. 

_, 1956, Microseisms associated with 

Tropical Cyclones over the North-East 
Australian Region. Tropical Cyclone 
Symposium, Brisbane. 

GRAVIMETRY 

The National Report on Gravity Surveys for 
the period 1954-1956 lists the gravity surveys 
carried out during that period, and illustrates 
them on a map. The following publications 
are listed: 

Marshall, C.E., andNarain, H., 1954. Regional 
gravity investigations in the eastern 
and central Commonwealth. Dept. 



Geology and Geophysics, University 
of Sydney. 

Thyer, R.F. and Everingham, I.B., 1956, Gra- 
vity survey of Perth Basin, Western 
Australia. Bur. Mm. Res. Aust. Bull. 33. 
The National Reports on Precision Levelling 
and Triangulation for the same period also 
include accounts of the work completed. The 
above reports were published by the Internation- 
al Association of Geodesy, Eleventh General 
Assembly, at Toronto, 1957. 

INDONESIA 

STANDING COMMITTEE MEMBER 

Dr. Th. H.F. Klompe. Geological Institute, 
University of Indonesia, Djl. Ganeca 
10, Bandung, Java. 

THE STATUS 01 GEOLOGICAL MAPPING IN INDO- 
NESIA 

This is the title of a report prepared by Th. 
H.F. Klompe for the Ecafe meeting in Bangkok 
in 1954, but brought up to date in October, 1957 2 . 
The Indonesian archipelago occupies about 4% 
of the area of the earth, and there are altogether 
about 7,000 publications on the geology and 
geophysics of the region. Owing to the con- 
siderable amount of work done by the joint effort 
of Geological Survey and oil and mining com- 
panies, and by private research, a fair area has 
been mapped in detail. Altogether about 80% 
has been mapped on a reconnaissance scale. 

The historical aspects of geological mapping 
are described, and there is a list of the published 
maps available. The general geological map of 
Indonesia on a scale of 1 : 1,000,000 will consist 
of 21 sheets, of which 12 have already been 
published, all accompanied by an explanatory 
note. 

Of 131 sheets of the geological map of Java 
on a scale of 1:100,000, 11 have been published 
with explanatory notes and detailed maps, 
sections and photographs. 13 sheets of 43 have 
been published of the 1 :200,000 map of South 
Sumatra. 

For the geological maps of Java and South 
Sumatra a system of colours and symbols are 
used as described by Ir. A.C. de Jongh (J.v.h.M. 
vol. 59, 1930, Part III, 56-71). The report con- 
tains a discussion on the colours and symbols. 



2 Published in: Indonesian Journ. f. Natural Science. Vol. 113. 1957. 



15 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



A new general geological map of Indonesia 
in four sheets has been prepared on a scale of 
1:2,000,000, using 20 shades of colours and 7 
symbols of dots and crosses. The map is com- 
piled from existing maps, which are listed. 

In 1953 detailed geological mapping was 
commenced in the crystalline schists of the 
Lalan-Assu area in West Timor. Another 
sequence of overthrust masses was found, as 
established by Brouwer, but the orogenic phase 
is younger (Middle Miocene) than formerly 
suggested, and corresponds to the main phase of 
diastrophism in the Outer Banda Arc. The 
area being mapped has been extended, and the 
work has included some gravity and magnetic 
measurements. 

Mapping was started in 1953 in Central 
Sumatra in the granite massive of Solok, and will 
be extended northeast and southwest to com- 
plete a section across Sumatra. Since 1954 the 
area of mapping has also been extended west and 
north-west, where a remarkable Permian volca- 
nic-sedimentary series has been mapped. 

Detailed mapping was started in 1954 in the 
Dwijo Hills and the northern part of the "Zui- 
dergebergte" (Southern Mountains) east of 
Djokjakarta. The area has pre-Tcrtiary meta- 
morphics unconformably overlain by Eocene, 
with both frequently interfolded. There are a 
number of sedimentation cycles and a flysch 
facie s. 

Detailed mapping was also started in the 
Duizendgebergic (Thousand Mountains) on the 
southcoast of Central Java, with a sequence of 
almost undisturbed middle and upper Miocene 
sediments. The name of this area derives from 
its morphologic character, and results to date 
indicate that the individual hills owe their 
location to the presence of bioherms. 

In east Java geological mapping was started- 
in 1957 in the Ringgit-Beser complex of younger 
volcanics belonging partly to the Mediterranean 
suite, covered in the south by young volcanic 
sediments. 

The report is accompanied by maps and 
figures to illustrate the maps mentioned above 
and the areas in which mapping has been carried 
out. 

GEOLOGICAL PUBLICATIONS FOR THE YEARS 
1953-1957: 

Marks, P., 1953, Preliminary note on the dis- 
covery of a new jaw of Meganthropus 
von Koenigswald in the lower middle 

16 



pleistocene of Sangiran, Central Java. 
Indonesian Journ. f. Nat. Sc. 109:26-34, 
1 fig. 2 plates, 1 map, Bandung. 

Klompe, Th. H.F., 1954, The structural impor- 
tance of the Sula Spur (Indonesia). 
Indonesian Journ. for Nat. Sc. 110: 
21-41, 8 figs. 

Marks, P., 1954, Contributions to the Geology 
of Timor. III. An occurrence of Miogyp- 
sina (Miogypsinella) Complanata 
Schlumberger in the Lala Asu Area 
Timor. Ind. Journ. f. Nat. Sc. 110: 
77-78, 4 figs. 

Osberger, R., 1954, Contributions to the Geology 
of Timor. IV. Notes on Plio-Pleis- 
tocene Corals of Timor. Indonesian 
Journ. f. Nat. Sci, 110:80-82. 

Waard, D. de, 1954, Contributions to the 
Geology of Timor. I. Geological re- 
search in Timor, an introduction. In- 
donesian Journ. f. Nat. Sci\ 110: 1-9, 5 
figs, and map. 

, 1954, Contributions to the Geology 

of Timor. II. The orogenic main 
phase in Timor. Ind. Journ. f. Nat. Sc. 
110:9-21, 10 figs, and map. 

... , 1954, Contributions to the Geology 

of Timor. V. Structural development of 
the crystalline schists in Timor, tecto- 
nics of the Lalan Asu Massif. Indone- 
sian Journ. /: Nat. Sc. 110:143-154, 
12 figs. 

., 1954, Contributions to the Geology 

of Timor. VI. The second geological 
Timor Expedition, preliminary results. 
Indonesian Journ. f. Nat. Sc. 110: 154-161, 
5 figs. 

Klompe, Th. H.F., 1955, On the supposed upper 
Paleozoic unconformity in North 
Sumatra. Indonesian Journ. f. Nat. Sc. 
111:151-166, 3 figs. 

Kraeff, A., 1955, A contribution to the petro- 
logy of the young extrusive and intrusive 
and intrusive rocks of the river-basin 
of S. Kajan. (N.E. Borneo). Djawatan 
Geologi, Bandung Publikasi Keilmuan, 
sen Petrologi, No. 29:11-19, figs and 
locality map. 

Waard, D. de, 1955, Contributions to the 
Geology of Timor. VII. On the 
Tectonics of the Ofu Series. Indonesian 
Journ. f. Nat. Sc. Ill: 137-144, 6 figs. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



, 1955, Contributions to the Geology 

of Timor. VIII. Tectonics of the 
Sonnebait Overthrust Unit near Niki- 
niki and Basleo. Indonesian Journ. f. 
Nat. Sc. Ill: 144-151 5 figs. 1 pi. 

Marks, P., 1956, Smaller Foraminifera from 
Well No. 1 at Kebajoran, Djakarta. 
Publikasi Kcilmuan No. 30, Seri Paleon- 
tologi, Bandung 1956. 

, 1956, Lexiquc Strdtigraphique Inter- 
national. Vol. Ill, Asie* Faxicule 7, 
Indonesia, Paris 1956. 

Obserger, R., 1956, Korallen als Hilf smittel der 
Tertiar und Quartar Stratigrafic Indo- 
nesiens. Publikasi Kcilmuan No. 32, 
Seri Paleontologi, Bandung 1956. 

Laufer, F. and Kraeff, A., 1957, The Geology 
and Hydrology of West-and Central- 
Sumba and their Relationship to the 
Water-supply and the rural Economy. 
Publikasi Kcilmuan No. 33, Sen Geo- 
logi, Bandung 1957. 

NATIONAL REPORT 01 WORK ON SEISMOLOGY 
(1951-1956) 

(Published by the Scismological Department, 
Meteorological and Geophvsical Institute, Dja- 
karta, April, 1957). 

SEISMOGRAPH STATIONS 

Djakarta Lat. 06 1 1' S. Long. 106 50' E h=8m 
(inaugurated 1898) Foundation: River 
quaternary. Seismograph: Wiechert Z 
1300 kg Wiechert N & E 1000 kg 

Bandung Lat. 0654'S. Long. 106^'37'E h=726 m 
(inaugurated 1948) Foundation: Qua- 
ternary volcanics. Seismograph: Wie- 
chert N &E 1000 kg 

Lembang Lat. 0650' S. Long. 107'37'Eh^ 
1295 m (inaugurated 1953) Founda- 
tion: Quaternary volcanics. Seismo- 
graph : Sprengnether Z (T 1 .4 sec) 
Sprengether N and E (T () = 15 sec) 

Medan Lat. 0333'N. Long. 9841'E h=32m 
(inaugurated 1956) Foundation: Young 
marine sediments. Seismograph: Spreng- 
nether Z,N and E (T = 1.5 sec). 

Because of serious difficulties in the construc- 
tion sector (building of adequate housing) it 
has still not been possible to install the seis- 
mographs in Kupang (Timor) and Menado 
(N. Celebes). Both stations are going to be 



equipped with a set of short-period Sprengether 
seismographs. 

MACROSEISMIC WORK 

The macroseismic bulletin for the years 1948- 
1955, prepared under the direction of R. Soetadi 
and A.R. Ritsema, is now in print. It will not 
be possible to bridge the gap between the years 
1942 and 1948; during these years no data of 
felt earthquakes have reached the Institute. 

The drafting of new blanks has been successful 
in so far that there is a marked improvement in 
number of reported shocks. The diligence of the 
voluntary observers, however, has not yet reached 
the pre-war level, seeing that the number of 
reported shocks has not yet reached the average 
of the last years before the war. 

From 1956 onward the bulletin will be pub- 
lished yearly, all reports than being based on the 
Modified Mercalli Intensity Scale. 

Important damage was caused by the Sum- 
bawa earthquake of November 2, 1954. A local 
shock with a very small macroseismic area caused 
considerable damage in Sumedang (W. Java) 
on August 14, 1955. 

MICROSEISMIC OBSERVATIONS AND RESEARCHES 

Preliminary readings are executed at every 
stations, and if necessary results are cabled to 
the Institute in Djakarta. Seismic bulletins of 
all Indonesian stations are prepared by W.F. 
Smeets. All seismograms are stored in Djakarta. 

Since January 1, 1957 also microseisms are 
read from the Djakarta seismograms under the 
direction of R. Soetadi. Results are published 
monthly as an annex of the Seismic Bulletin. 

Some focal mechanism studies of SE Asian 
earthquakes have been executed. These inves- 
tigations will be continued during the next 
years. The method used so far is extended, so as 
to include also the initial motion of the S waves. 

BIBLIOGRAPHY 

Ritsema, A.R. A strong earthquake near Bima 
(Sumbawa) Indon. Jour, Nat. Sc., 110: 
214-215 (1954). 

, The fault plane technique and the 

mechanism in the focus of the Hindu 
Kush earthquakes. Indian Jour. Meteor. 
&Geoph. 6:41-50(1955). 

, Amplitudes of bodily seismic waves 

Indon. Jour. Nat. Sc., 112, (1956). 

17 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Ritsema, A, R., The mechanism in the focus of 
28 SE Asian earthquakes. Verhand. 50, 
Meteor. & Geoph. Inst., Djakarta, (1956). 

, Stress distributions in the case of 

150 earthquakes Geol & Mijnb., Nw. 
Ser., 19:36-40(1957). 

_-, Pacific and Mediterranean earth- 
quake mechanisms Trans. Am. Geoph. 
Un. 38, (1957). 

, Earthquake generating stress systems 

in SE Asia Bull. Seism. Soc. Am., 
47, (1957). 

, On the use of transverse waves in 

earthquake mechanism studies. Ver- 
hand. 52, Meteor. & Geoph. Inst., 
Djakarta (1957). 

Soetadi, R. and A.R. Ritsema -The earthquake 
of November 2, 1954 near Sumbawa 
Island. Verhand. 47, Meteor. & Geoph. 
Inst., Djakarta (1955). 

THAILAND 

STANDING COMMITTEE MEMBER 

Mr. Yija Sethaput, Royal Department of Mines, 
Bangkok. 

SUMMARY OF GEOLOGICAL DEVELOPMENT IN 
THAILAND SINCE 1953. 

(Report received from Geological Survey Divi- 
sion, Bangkok). 

During the past three years routine reconnais- 
sance survey uncovered tremendous amounts of 
fossils in diverse localities. Notable among these 
are the fossils collected during the joint Malay- 
Thai investigation (for mutual correlation pur- 
poses) along the adjoining border areas. This 
work was done from November 1955 till February - 
1956 and Upper Cambrian, Middle Ordovician, 
Lower Silurian, Carboniferous and Permian 
fossils were discovered. 

In 1954 the Central Plain of Thailand, an area 
of some 26,000 square kilometers, was covered 
with an aeromagnetic survey and four anomaly 
closures were found. One of these was explored 
by terrestric gravitymeter surveying and drilling 
is being done to test the underlying formations for 
possible economic development. Further aerial 
survey work, including magnetometer, scintilla- 
tion counter and perhaps electromagnetic 
induction instrument, is expected to be under- 
taken over three known mineralized areas. The 

18 



flights will be made under contract and will start 
early next year. 

Radio-active minerals of doubtful economic 
value were discovered in tin mines in the south. 
Iron, tin, tungsten, manganese, gypsum, salt and 
fluorite deposits were surveyed during this period. 

A groundwater project has been carried out 
since 1955 with the aim to help develop water 
resources for the NE., in an area about one 
third of Thailand. This is in the plateau area, 
where surface water is usually very scant, due to 
absorption by the underlying sandstone forma- 
tions. Many holes have been drilled with a 
coverage about 60 per cent. Most failures are 
due to the occurrence of salt water. 

The lack of reasonably good maps has been 
an important problem to the Geological Survey. 
Compilation of geological information has to 
be done on a reconnaissance base. Fossil localities 
are specially emphasized so that when good maps 
will become available, the strata can be readily 
traced in a proper way. Beside, identification of 
the fossils may indirectly be used for generalisa- 
tion of the stratigraphy of Thailand. 

The Geological Survey is also faced with the 
lack of personnel. This may be due to the 
public feeling that geologists are confronted with 
personal risk and a hard occupation, while 
getting paid the same as other technicians who 
work in town. Last but not least, is the meagre 
yearly budget resulting in only a few short trips 
each year. However, since the last few years, 
we received aid from the U.S. Government 
through ICA and many of our needs were 
realized. Material and monetary aids are very 
substantial, and geologists have the chance to 
be selectively trained abroad. 

It is very gratifying to know that the Govern- 
ment is now really becoming interested in the 
work of the Geological Survey and intends to 
enlarge its budget in the future. 

Owing to lack of funds and personnel, the 
Survey has not participated in this International 
Geophysical Year. 

PHILIPPINES 

STANDING COMMITTEE MEMBER 

Mr. Arturo Alcaraz, Commission on Volcano- 
logy, University of the Philippines, 
Quezon City. 



PROGRESS OF GEOLOGIC SURVEY IN THE PHILIP- 
PINES SINCE 1953 

(By Elpidio Vera and Arturo Alcaraz). 

The Philippine Bureau of Mines conducted 
detailed geologic surveys mainly in areas of 
known mineral deposits. Little or no regional 
geology was attempted. However, reconnais- 
sance mapping covered 1.7 million hectares in 
33 provinces. There is also in progress a project 
of measurement of stratigraphic sections in the 
Cagayan Valley covering 50,000 hectares. An 
airborne magnetometer survey of six principal iron 
areas in Luzon, Visayas and Mindanao was com- 
pleted by Hunting Geophysics, Ltd. of London in 
1 954 for the Philippine Government. Since the last 
couple of years or so oil concessionaires have con- 
ducted geophysical surveys in their respective 
concessions, covering in particular, the Cagayan 
Basin, parts of Panay island, and Cotabato. 
Some of these oil companies also made ground 
reconnaissance surveys in a number of provinces. 

Paleontologic and stratigraphic studies have 
advanced considerably as a result of close cooper- 
ation between the technical staffs of the petro- 
leum companies and the Bureau of Mines. 

In the past four years significant contribu- 
tions have been made to the geology of the coal 
deposits of Central Cebu, Malangas (Zamboanga 
del Sur), Batan Island (Albay), Catanduanes, 
Semirara (Antique), Bulalacao (Mondoro), 
Bislig (Surigao) and Polillo (Quezon) ; the geology 
of copper deposits in Antique, Cebu, Repu-Rapu 
Island (Albay), Botolan (Zambales), Sipalay 
(Negros Occidental); and the geology of chromite 
deposits in Zambales and of manganese depo- 
sits in the Anda Peninsula (Bohol). 

The coal and strategic minerals investigations 
conducted by the Philippine Bureau of Mines in 
cooperation with International Cooperation 
Administration and the results of exploration 
work of the petroleum companies brought out 
much information leading to a clearer under- 
standing of the Tertiary formations, structures, 
and stratigraphic sequence in the Philippines. 

The results of detailed surveys by the Bureau 
of Mines are published under the Special Projects 
Series of which 10 volumes are now available. 

With but few exceptions all additional geologic 
data gathered from various sources up to the 
time of writing have been incorporated in a 
geologic map of the Philippines that is to be 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

submitted to the ECAFE Convention in India 
this coming November. 

Volcanological Observations and studies of 
the active volcanic areas of the Philippines were 
continued by the Commission on Volcanology. 
Two-component seismographs have been in- 
stalled at Taal, Mayon, Hibok-Hibok, Canlaon, 
and Apo. A water tiltmeter of the type being 
used in Hawaii has also been installed in the 
Mayon area, with others due to be set up at other 
volcanological stations during the year. Magne- 
tic and petrographic studies are also being under- 
taken by the Commission on Volcanology. 

INTERNATIONAL GEOPHYSICAL YEAR 

The Bureau of Coast and Geodetic Survey and 
the Philippine Geodetic and Geophysical Insti- 
tute will carry out measurements of the earth's 
magnetic field. Observations are now being 
made at the Muntinlupa Magnetic Observatory. 

In oceanography the Bureau of Coast and 
Geodetic Survey will carry out measurements of 
tide, temperature and salinity at five regular sta- 
tions and two additional ones established for 
IGY. C & GS ships have been instructed to 
take oceanographic measurements wherever they 
should happen to be during the IGY. 

The Manila Observatory and the Geophysical 
Division of the Weather Bureau will participate. 
The Manila Observatory will continue its regular 
program of seismic recordings from its five 
Sprengnether seismometers. Microseismic stud- 
ies will also continue. Geophysical Division will 
also continue its regular program of seismic 
recording and microseismic work, and studies 
on the relation of microseisms to ocean storms 
will continue. 

There will be no Philippine work on gravity 
measurements, but a United States party will make 
some during the latter part of 1957. 

OBITUARY 

The death of Dr. Jose M. Feliciano on 22 
February 1955 is recorded with regret. He 
attended the 7th Congress in New Zealand, 
and was Chairman of the Division of Geology 
and Geophysics at the 8th Congress, as well as a 
member of the Standing Committee on Volcano- 
logy. His unassuming manner and cheerful 
personality will be remembered by all who knew 
him. 

19 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 

TAIWAN 



STANDING COMMITTEE MEMBER 

Dr. V.C. Juan, Head of the Department of 
Geology, National Taiwan University, 
Taipei, Taiwan, China. 



RECENT DEVELOPMENT 
IN GEOLOGY IN TAIWAN 

In the preparation of this report, the first task 
is to have a survey of the relevant literature on the 
geology of Taiwan and then compile the biblio- 
graphies grouped in the following four categories: 

(1) general and structural geology, (2) stratigraphy 
and palaeontology, (3) mineralogy and petrology, 
and (4) mineral resources. It is intended to 
provide a background for the work of this 
Standing Committee and a guide in initiation and 
encouragement of co-operative research on the 
geological problems of the Pacific region. It helps 
in an assessment of the past achievement and 
points the way to fruitful advance. 

GENERAL AND STRUCTURAL GEOLOGY 

The origin of the island of Taiwan has been the 
subject of theories and hypotheses. A hypothesis 
of coastal range of the Asiatic continent has been 
expressed by Juan (1955). He has attempted to 
attack the problem from various angles such as 
structural correlation between the continent and 
the island, the ill comparison between Riukiu 
arc and Philippine Archipelago and the island, 
the origin of Formosa Channel, the causes of 
present simple shore line, and the submarine 
topography around the island, and concluded that 
the island of Taiwan has long been in existence 
and is actually a part of the old land of Fukien 
province. Taiwan island should be regarded as the 
coastal range of the continent. 

In connection with the study of oil possibilities 
of Taiwan, Biq (1956), taking the East Indies as 
a perfect example, advocated an origin of a 
double island are with morphotectonic elements 
from east to west of (1) a volcanic inner arc, 
represented by the submarine ridge on which two 
off-shore island, Lutao and Lanhsu are situated, 

(2) non- volcanic outer arc of Central Mountain 
of the island, and (3) a foredeep, now occupying 
the coastal plain of western Taiwan and a part of 
Taiwan Strait. However, he failed to explain, 
just like most of the Japanese geologists who 
advocated the origin of an island arc before, 

20 



the reverse direction of the curvature of the 
island which has a convexity facing the continent, 
and disregarded the absence of epicontinental 
seas behind the arc, an important feature of all 
arc structures, and thus contradicting the theory 
of formation of arcs by the underthrusting of 
a simatic layer from the ocean toward the con- 
tinent. 

Although there are different views about the 
origin of the island, it is the consensus of opin- 
ion that the island is mainly occupied by Terti- 
ary geosynclines. The eugeosynclinal nature of 
the sediments in the East Coastal Range of the 
island is especially clear after the detailed study 
by Hsu (1956). 

However, more extensive studies on sedi- 
mentation, igneous activities and orogenies of 
such geosynclines are needed before we can 
agree on the origin of the island. An outline of 
such studies was published by Juan (1957) quite 
recently. 

A geological map of Taiwan on a scale of 1 to 
300,000 was published by the Geological Survey 
of Taiwan in 1953. 

RELATED BIBLIOGRAPHY, 1953-1957 

Biq, C.C., (1956), The tectonic framework and 
oil possibilities of Taiwan. Mem. Nation- 
al Taiwan Univ., 95-105. 

Hsu, T.L., (1954), On the geomorphic feature, 
and the recent uplifting movement of 
the Coastal Range, Eastern Taiwan. 
Bull. GeoL Surv. Taiwan, 7: 51-57. 

Hsu, T.L., (1 956), Geology of the Coastal Range, 
Eastern Taiwan. Bull. GeoL Surv. Taiwan, 
8: 39-63. 

Juan, V.C., (1955), Physiography and geology 
of Taiwan. Annals of Academia Sinica, 
2.1: 59-90. 

Juan, V.C., (1957), Continental rifting and 
igneous activities in the Neogene mar- 
ginal geosynclines of Taiwan. Proc. 
9th Pacific Science Congress (MS). 

Wang, C.S., (1956), The structural evolution 
and oil accumulation in Taiwan. Mem. 
National Taiwan University, 106-109. 

STRATIGRAPHY AND PALEONTOLOGY 

The geologic age of the metamorphic rocks in 
the Central Mountains has been a much disputed 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



problem among the geologists in Taiwan. Most 
of the fossils found in this metamorphic com- 
plex are very poorly preserved and deny accurate 
determination. Recent collecting from the 
fusuline limestone by Yen (1953), however, 
suggest schwagerinids or neoschwagerinids and 
also Waagenophyllum among coral specimens. 
Thus both fusulines and corals point to a late 
Palaeozoic age. 

Encouraged by these findings, geologists began 
to suspect that there may possibly be a Mesozoic 
formation between the late Palaeozoic and 
the Paleogene rocks. It is reported (Yen et al., 
1956) that in the lower part of the Paleogene 
slate formation, traces of organisms, such as 
spines of cchinoids and Orbitolina, have been 
noted in the basal conglomerate layers. Thus 
there is a possibility these may be of Cretaceous 
age; and only the upper portion of the slate 
formation, in which Discocyclina, Camerina, 
Assilina and Pallatispira (?) of a middle and late 
Eocene fauna have been found, belongs to the 
Paleogene. This certainly poses as an important 
problem that calls for attention. 

A discovery of ammonite-fossils was made in 
a bore-hole for petroleum in 1956, in the western 
marginal belt of the western coastal plain. The 
age of this fossiliferous bed is tentatively fixed as 
Upper Jurassic (Lin, 1957). Further verification 
of the presence of Jurassic in the central area of 
the island is thus urged. 

Geologists generally now agree that Oligocene 
formations are definitely present in the island. 
Wang (1953) suggested that a part of Mushan 
coal formation, which lies disconformably below 
the Kungkuan tuff formation of early Miocene 
age, may belong to the Oligocene; based on his 
careful stratigraphical and sedimentological 
studies of the latter formation in northern 
Taiwan. The problem of ocurrence of the 
Oligocene formation is further elucidated by 
Chang (1954a) in his study on smaller forami- 
nifera collected at Yuhang. According to 
Chang, the Suichangliu (Suichoyu) and Suo 
formations, both had been formerly included in 
the "Slate formation", are more closely related 
to formations of the Urai and Suo group con- 
taining smaller forms of Camerina, Assilina 
and Discocyclina rather than to the lower to 
middle Miocene Hsichih group, and that the 
Aoti coal measure, the lowest coal measure in 
Taiwan, may also be of lower Oligocene age. 
A re-study of the fossils of Cyclamina, collected 
from Suo and Urai groups, led to the conclusion 



that the rocks containing them are of Oligocene, 
rather than of Eocene age (Chang, 1953). 

Stratigraphic correlation of Miocene and 
Pliocene formations between northern and 
southern Taiwan has long been a vexing 
problem for many geologists. It is grateful to 
note that an attempt has been made by Ho 
(1956), thus knowledges of sedimentation, ecology 
and facies concept find wider application to 
stratigraphy. According to Ho, the shelf-type 
Miocene sediments are predominant in northern 
Taiwan, while the sedimentation in southern 
Taiwan appears to be exclusive development of 
a basinward or geosynclinal facies. A number 
of rock-stratigraphic or lithologic units are 
re-classified. However, the importance of bio- 
stratigraphic subdivision has also been stressed 
by Oinomikado (1956). 

RELATED BIBLIOGRAPHY, 1953-1957 

Chang, L.S., (1953), Tertiary Cyclamina from 
Taiwan and their Stratigraphic signi- 
ficance. BulL Geol. Surv. Taiwan, 4: 

27-37. 

Chang, L.S., (1954a), The lower Oligocene 
Yuhangian foraminiferal fannule and 
its Stratigraphic significance in Taiwan. 
Bull. Geol. Surv. Taiwan, 5: 101-116. 

Chang, L.S., (1954b), Two new species of small- 
er foraminifera from the Miocene of 
Taiwan: Gaudryina ( Pseudogaudryina ) 
Kokuseiensis and Karreriella Shang- 
taoensis. Bull. Geol. Surv. Taiwan, 7: 
59-61. 

Chang, L.S., (1956a), On the correlation of the 
Ncogene formations in western Taiwan 
and some diagnostic species of smaller 
foraminifera. Mem. Nat' I Taiwan Univ. 
113-121. 

Chang, L.S., (1956b), Two species of Lingulina 
from the Miocene of Taiwan. BulL 
Geol. Surv. Taiwan, 8: 65-66. 

Chang, L.S., (1956c), A new Spiroplectammina 
from the Miocene of Taiwan. BulL Geol. 
Surv. Taiwan, 8: 67-68. 

Ho, C.S., (1956), Miocene rocks of the Chu- 
touchi oil field. Taiwan. BulL Geol. 
Surv. Taiwan, 8: 15-38. 

Lin, C.C., (1957), Personal communication. 

Oinomikado, T., (1956), Problems of bio- 
stratigraphic correlation in Taiwan. 
Mem. N at* 1 Taiwan Univ., 110-112. 

21 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Wang, Y., and Huang, T.C., (1953), A strati- 
graphic study of the Kungkuan tuff 
formation, Northern Taiwan. Acta 
Geologica Taiwanica, 5 : 35-46. 

Yen, T.P., (1953), On the occurrence of the late 
Palaeozoic fossils in the metamorphic 
complex of Taiwan. Bull. Geol Surv. 
Taiwan, 4: 23-26. 

Yen, P.T. et al., (1956), Some problems on 
Mesozoic formation of Taiwan. Bull. 
Geol. Surv. Taiwan, 8:1-14. 



MINERALOGY AND PETROLOGY 

In the field of mineralogy and petrology, 
great progress has been made in recent years. 
Huang (1953) has made a detailed morpho- 
logical study of the adularia crystals collected 
from quartz veins in the schists. He has also 
made a genetic study of the basaltic hornblende 
in andesite from Tatun volcanoes and concluded 
that the black hornblende may have been derived 
from a green variety by heating, and the brown 
varieties from black ones by reheating, in which 
the transition of magnetite to hematite may 
have also occurred, resulting in the pale red- 
dish colour of the andesites (Huang, 1954). 

In 1953, one of a series of studies of basic and 
ultrabasic rocks of the East Coastal Range, 
undertaken by Juan (1953) and his co-workers, 
was published. A new basaltic glassy rock was 
named as Taiwanite representing a distinct 
magma-type. According to Juan, the magma 
that produced Taiwanite, a liquid massed with 
olivine and plagioclase crystals, accumulating at 
the time of intrusion, is the parental magma of 
the plateau basalts recognized by Washington. 
The chemical laboratory of the Department of 
Geology, National Taiwan University, has also^ 
published 98 complete analyses of basic and ul- 
trabasic rocks in Taiwan, a valuable contribution 
to the science of geochemistry (Juan, et al., 
1955). 

In the field of petrology of sedimentary rocks, 
an excellent contribution was made by Wang 
(1954) on the study of graywacke from Nan- 
kangshan near Taipei. Is mineralogical com- 
position is given and its genesis is discussed. 
Thus the geosynclinal nature of the Tertiary 
sedimentation in western Taiwan is clearly 
demonstrated. Slump features associated with 
graded bedding in the Miocene sediments of the 
East Coastal Range were also carefully studied. 
Since such contemporaneous deformational fea- 

22 



tures are quite common in the active volcanic 
belts, bordering the continents, not necessarily 
a record of ancient earthquakes, as so interpreted 
by Hsu (1954), the eugeosynclinal nature of the 
sediments, distinctive to those found in the 
miogeosynclines, is indicated. 

The metamorphic complex of the Central 
Mountain Range that occupies nearly half of the 
area of the island is still a virgin ground for study. 
However, a good start has been made on the 
petrography of the gneisses (Yen, 1954a), thus 
rough sketch of the process responsible for the 
formation of these rocks could be outlined. 
Yen (1954b) also showed that the green rocks, 
including chlorite schists, amphibolites, serpen- 
tine and meta-diabase, have closer genetic 
relations to one another and they were formed 
commonly from basic igneous rocks or their 
pyroclastic equivalents by low grade metamor- 
phism. Since the geohistory of the whole com- 
plex is not yet clear, the present data on hand 
are not adequate to formulate a sequence of the 
formation of such rocks petrologically and 
geologically. Further field study is neecded. 

Some geological problems posed by the 
schist formations in the Central Mountain 
Range have also been recognized (Yen, 1954c). 
These involve mainly the principal rock types and 
geological structures of the schist formations. 



RELATED BIBLIOGRAPHY, 1953-1957 

Hsu, T.L., (1954), On the contemporaneous 
deformation of the sedimentary rocks 
in the Coastal Range, Eastern Taiwan. 
Bull. Geol. Surv. Taiwan, 6:61-56. 

Huang, C.K., (1953), Adularia from Kukutzu, 
Taiwan. Acta Geologica Taiwanica, 
5:27-34. 

Huang, C.K., (1954), Basaltic hornblende from 
the Tatun volcanoes, Taiwan. Acta 
Geological Taiwanica, 6: 113-124. 

Juan, V.C., Tai H. & Chang, F.H., (1953), 
Taiwanite, a new basaltic glassy rock 
of East Coastal Range, Taiwan and its 
bearing on the parental magma-type. 
Acta Geologica Taiwanica, 5: 1-25. 

Juan, V.C. Tai, H. & Hsu T.C., (1955), Chem- 
ical analyses of igneous rocks a pro- 
gress report of the chemical Laboratory. 
Acta Geologica Taiwanica 7:43-65. 

Wang, Y., (1954), Graywacke from Nan- 
kangshan and its vicinity, east of Taipei 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



City. Ada Geologica Taiwanica, 6 : 
125-131. 

Yen, T.P., (1954a), The gneisses of Taiwan. 
Bull. Geol Surv. Taiwan, 5:1-100. 

Yen, T.P., (1954b), The green rocks of Taiwan. 
Bull. Geol. Surv. Taiwan, 7: 1-46. 

Yen, T.P., (1954c), Some geological problem on 
the Tananao schist. Bull. Geol. Surv. 
Taiwan, 7:47-50. 

MINERAL RESOURCES 

The most important mineral resources under 
exploration and mining in the island are coal, 
petroleum and gold-copper deposits. 

Coal fields are exclusively located in the 
northern part of Taiwan and have been worked 
for many years. However, for the purpose 
of increasing production, a new field, the Nan- 
chung coal field, has recently been mapped in 
detail. It covers an area of 162 sq. km. and 
includes 3,000 m of Miocene sediments. Al- 
though there are three coal-bearing formations 
in the Miocene strata, the Middle coal-bear- 
ing formation is by far the most important, 
consisting of three coal seams. The coal pro- 
duced is medium-volatile bituminous, low in 
ash and sulphur. It possesses good heating 
properties and is excellent for making metallur- 
gical coke (Ho, et al., 1954). Another brown 
coal field in the upper coal-bearing formation 
of Miocene age in Miaoli has also been surveyed 
(Ho, 1953). 

A program to re-estimate the coal reserves of 
the whole island, initiated by the Ministry of 
Economic Affairs, is now under way. 

Although the gold-copper deposits of Chin- 
kuashih and Chiufen districts have been mined 
extensively for a long time in the past, the first 
published account of the geology of the deposits 
appeared only very recent (Wang, 1953). This 
report covers the general stratigraphy of the area, 
the mode of occurrence of the deposits and the 
age of dacite intrusions in which gold-copper 
deposits are found. The fracture pattern of the 
mining areas which directly controls the locali- 
zation of the ore-forming solutions has also 
been analyzed (Wang, 1955). Among the com- 
plicated folding and thrusting, normal faulting is 
said to be followed by the mineralization of 
gold and copper. The mineralogy of the ore 
bodies, their genesis, and the associated wall 
rock alterations have further been investigated 



(Huang, 1955). All this detailed work should be 
of value to future exploration of new ore bodies 
in the said mines. 

Thougji Taiwan is known to produce a small 
quantity of oil, the petroleum potentialities of 
the island have long been a subject of discussion. 
In recent years, the Chinese Petroleum Cor- 
poration embarked on an expanded program of 
systematic oil exploration. Considerable pro- 
gress has been made by the Corporation in build- 
ing up efficient technical organizations to in- 
crease the pace and scope of exploration survey 
activity. Attention has been concentrated not 
only on a more detailed survey of known shallow 
structures along the foothill region, but also 
on the establishment of deep drilling projects 
in the coastal plain (Meng, 1957). 

During 1953-1954, re-evaluation of the shallow 
structures of previous test drilling was made. 
Based on detailed sub-surface studies, extension 
wells were selected in Chuhuangkeng oil field 
and Chinshui gas field and a wildcat was located 
on the southern plunge of the large Chutouchi 
structure. All these wells were successful in 
finding production and a new oil field was dis- 
covered in January 1954 at the Chutouchi south 
culmination. Small production has also been 
proved on the Shantzechio structure, near Tai- 
pei. Selection of locations for deep tests on the 
coastal plain began in 1957 (Stach, 1957). 

Two symposia on petroleum geology of 
Taiwan were successfully conducted by the 
Department of Geology, National Taiwan Uni- 
versity in November, 1955, and the Chinese 
Petroleum Corporation in June, 1956. In the 
first meetings, discussion was centered on the 
problem of potentialities of oil in the coastal 
plain and in the second gathering, past achieve- 
ments were reported and a future plan of 
exploration was presented. In summing up the 
opinion of geologists towards the prospects of 
oil in Taiwan, Prof. H.G. Schenck (1957) has 
remarked that "exploration for petroleum re- 
quires thorough and systematic teamwork over 
a considerable period of time and, where the 
geological conditions appear to be as favourable 
as they are in Taiwan, success should ultimately 
be achieved". 

An investigation of monazite and zircon sands 
occurring along the beaches and streams in 
western Taiwan has been carried out. The 
mineral components of the heavy sands are 
estimated to be no less than 20 different species 
among them: monazite (1-2%), zircon (0.3-55%), 
ilmenite (14-45%) and magnetite (5-80%), are 

23 



PROCEEDINGS OF THE NINTH PACIHC SCIENCE CONGRESS 



the four important ones (Chen, 1953). An 
investigation of ground water resources in 
Changhua and Yunglin districts has also been 
made (Wang & Chen, 1955). 



RELATED BIBLIOGRAPHY, 1953-1957 

Bien, Edward, H.N., 1957, The importance of 
the things we do not know. Sympo. 
Petrol. GeoL Taiwan, Chinese Petrol. 
Corp., 42-24. 

Chang, S.L., 1957, Preliminary results of 
sedimentation study of the white sand- 
stone member of the Nanchuang coal- 
bearing formation in the vicinity of 
Miaoli. Sympo. Petrol. GeoL Taiwan, 
Chinese Petrol. Corp., 122-126. 

Chang, S. and Chung, C.T., 1957, Geology 
of the Chutouchi structure, Tainan 
district. Sympo. Petrol. GeoL Taiwan, 
Chinese Petrol. Corp., 245-249. 

Chen P.Y., 1953, Heavy mineral deposits of 
western Taiwan. Bull. GeoL Surv. 
Taiwan, 4 : 1 3-2 1 . 

Chiu, H.T., 1957, Geology of the Yangmeipai 
(Pakuali) structure Miaoli district. 
Svmpo. Petrol. GeoL Taiwan, Chinese 
Petrol. Corp., 161-163. 

Heh, Kenneth, 1957, Subsurface geology of 
Chinshui gas field and correlation with 
the stratigraphic sequence on the west- 
ern flank of Chuhuangkeng structure. 
Symp. PetroL GeoL Taiwan. Chinese 
Petrol. Corp., 106-108. 

Heh, K. and Hsiao, P.T., 1957, Geology of 
the Tunghsiao anticline, Mioali district. 
Sympo. Petrol. GeoL Taiwan, Chinese 
PetroL Corp., 139-141. 

Ho, C.S. and Keng, W.P., 1953, Geology and 
mineral deposits of the area between 
peipu, Hsinchu and Nanchuang, Mia- 
oli. Bull. GeoL Surv. Taiwan, 4:1-12. 

Ho, C.S. et al., 1954, Geology of the Nan- 
chuang coal field, Miaoli, Taiwan. 
Bull. GeoL Surv. Taiwan, 6:1-59. 

Hsio, P.T., 1957, Subsurface data from well 
st-1 on the Shantzechiao structure, 
Taoyuan district. Sympo. Petrol. GeoL 
Taiwan, Chinese PetroL Corp., 170-173. 

Huang, C.K., 1955, Gold-copper deposits of 
the Chinkuashih mine, Taiwan. Acta 

24 



GeoL Taiwanica, 7:1-20. 

Lin, C.C., 1956, A stratigraphical interpreta- 
tion of the Miocene oil bearing forma- 
tions of western Taiwan. Mem. Nafl 
Taiwan Univ. 123-125. 

Ma, T.Y.H., 1957, The relation between Ceno- 
zoic diastrophism and petroleum re- 
sources beds of the western Pacific 
(Summary). Sympo. PetroL GeoL Tai- 
wan, Chinese PetroL Corp., 13-14. 

Meissner, C.R., 1957, Oil and gas prospects 
of Taiwan. Sympo. PetroL GeoL Tai- 
wan, Chinese PetroL Corp., 35-39. 

Meng, C.Y., 1957, Review of recent petroleum 
exploration surveys in Taiwan (Sum- 
mary). Sympo. PetroL GeoL Taiwan, 
Chinese PetroL Corp., 53-62. 

Oinomikado, T., 1957, Micropaleontological 
investigation of subsurface samples 
from seismic survey shot holes in Tainan 
district. Svmpo. PetroL GeoL Taiwan, 
Chinese PetroL Corp., 272-282. 

Oinomikado, T. and Huang, T.Y., 1957, 
Micropaleontological investigation of 
the Kucitauchi section near Chutaochi 
oilfield. Sympo. PetroL GeoL Taiwan, 
Chinese PetroL Corp., 257-263. 

Oinomikado, T. and Huang, T.Y., 1957, Mi- 
cropaleontological investigation of sub- 
surface samples from Chutaochi oilfield. 
Svmpo. PetroL GeoL Taiwan, Chinese 
PetroL Corp., 267-270. 

Pan, P.H., 1957, Seismic survey of Tunghsiao 
anticline, Miaoli district, Sympo. PetroL 
GeoL Taiwan, Chinese PetroL Crop., 
145-146. 

Schenck, HG.G., 1957, Petroleum exploration 
policy in Taiwan. Sympo. PetroL GeoL 
Taiwan, Chinese PetroL Corp., 5-8. 

Stach, L.W., 1956, Problem of petroleum 
geology in Taiwan. Mem. Nafl Taiwan 
Univ. 84-94. 

Stach, L.W., 1957a, Petroleum potentialities 
and exploration for oil in Taiwan. 
Svmpo. PetroL GeoL Taiwan, Chinese 
PetroL Corp., 15-28. 

Stach, L.W., 1957b, Stratigraphic subdivision 
and correlation of the upper Cenozoic 
sequence in the foothill region east of 
Chiayi and Hsinying. Sympo. PetroL 
GeoL Taiwan, Chinese PetroL Corp., 
178-213. 

Sun, S.C., 1957, Subsurface geology of Chu- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



touchi south culmination oil field. 
Svmpo. Petrol. GeoL Taiwan, Chinese 
Petrol. Corp. 254-256. 

Wang, C.S. and Chen, C.S., 1955, Geological 
investigation on the ground water 
resources in and around Tachushuichi 
fan between Changhua and Yungiin 
district. A eta Geo/ogiea Taiwan tea 
7 : 35-43. 

Wang, Y., 1953, Geology of the Chinkuashih 
and Chiufen district, Taiwan. Ada 
Geologiea Taiwanica. 5 : 47-64. 

Wang, Y., 1955, Fracture patterns in Chin- 
kuashih area, Taipci-Hsien, Taiwan 
A eta Geologiea, 7 : 21-34. 

Wang, Y. and Wang, CM., 1957, Cementing 
materials in some Tertiary sandstones 
from Taiwan. Sympo. Petrol. Geol. 
Taiwan, Chinese Petrol. Corp., 65-80. 

Wang, Y.L. and Chang, S., 1957, Coordina- 
tion of data drom the Chungchou wildcat 
and seismic surveys in the Tainan. 
Svmpo. Petrol. GeoL Taiwan, Chinese 
Petrol. Corp., 297-298. 

JAPAN 

STANDING COMMITTEE MEMBERS 

Professor T. Kobayashi, Geological Institute, 
Faculty of Science, University of Tokyo, 
Tokyo. 

Dr. T. Minakami, Head of Division of Volca- 
nology, National Committee for Geo- 
physics, Science Council of Japan, 
c/o Earthquake Research Institute. 
Tokyo University, Tokyo. 

Professor Kobayashi has forwarded the follow- 
ing list of publications of importance since the 
8th Pacific Science Congress. 

Geological Survey of Japan, 1956, Geology and 
Mineral Resources of Japan. 



Geological Survey of Japan, 1953, Geological 
Map of Japan, 1 : 3,000.000. 

Kim ura, T., 1957, The Discovery of a low 
Angle Thrust along the Mikabu Line 
in East Kii Peninsula, Western Japan, 
etc. Jour. Earth Sei. Nagova Univ. 
2 : No. 2. 

Kobayashi, T., 1953, Geology of Korea with 
Special Reference to the Limestone 
Plateau of Kogendo. Jour. Fae. Sei. 
Univ. Tokyo Sect. 2, 8 : Pt. 4. 

, 1954, On the Tectonic History of 
Taiwan (Formosa) Ibid. 9 : Pt. 2. 

_ , 1956, A Contribution to the Geotec- 
tonics of North Korea and South 
Manchuria. Ibid. 10: Pt. 2. 

, 1956, The Triassic Akiyoshi Oroge- 
ny. Geotektonisehes Symposium lu 
Flhren Hans Stille. Stuttgart. 

, 1956. The Shifting of the Chert- 
bearing Facies caused by the Migration 
of Gcosyncline. Gedenkh. H.A. Brou- 
\ver. Verhand. van het Koninkl. Nederl. 
GeoL Mijnh. 14. 

Kojima, G., 1954, Geological Situation of the 
Cretaceous Hiroshima Granite. Jour. 
Sei. Hiroshima Univ. Ser. C, 1 : No. 4. 

Makiyama, J., 1954, Syntectonic Construction 
of Geosynclinal Neptons. Mem. Coll. 
Sei. Univ. Kyoto, Scr. B, 21 : No. 2. 

Minato, M. Yagi, K. and Hunabashi, M., 1956, 
Geotectonic Synthesis of the Green 
Tuff Regions in Japan. Bull. Earthq. 
Research Inst. Tokyo Univ. 34 : Pt. 3. 

Tsuboi, C., Jitsukawa, A., Tajima, H., and 
Okada, A., Gravity Survey along the 
Lines of Precise Levels throughout 
Japan by Means of a Wordcn Gravime- 
tcr. Pts. 1-9. Ibid. Suppl. 4 : Pts. 1-8. 



DISCUSSION 



At the end of the Report the Chairman and 
Mr. Alcaraz asked for comments on it. 

Mr. G.W. Grindley of New Zealand suggested 
an addition of Antarctic geologic reconnaissance 
work being done by two parties i.e. at the northern 
extremity of the New Hebrides and a site in the 
Ross Sea. Also he would like to mention the 
successful operation between France and New 
Zealand in exchanging geologists between New 



Caledonia and New Zealand, the two islands 
having quite a common geological set up. 

Dr. Th. H.F. Klompe wished to point out that 
a Geologic Map of Indonesia on a scale of 
1 : 2,000,000 has now been finished. It covers 
about 80 per cent of the total area of which only 
about four and a half per cent was systematical- 
ly surveyed in detail. 

25 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Addendum 

DATUM-PLANES IN THE GEOLOGICAL HISTORY 

OF THE PACIFIC REGION. 
SUPPLEMENTARY BIBLIOGRAPHY 1953-1957 



R. S. ALLAN 

University of Canterbury, Christchurch, New Zealand. 



The list of references which follows, and in the 
compilation of which I have had help from a 
number of colleagues over-seas, is intended to 
supplement the bibliographies published in the 
"Report of the Standing Committee on Datum- 
planes in the Geological History of the Pacific 
Region" (Proc. Eighth Pacific Set. Congr., 1953, 
II, 1956, 325-423). 

It is selective, does not aim at completeness, 
and refers only to the topics discussed in the 
earlier Report. 

It has been prepared at the request of J. 
Healy, Chairman of the Standing Committee on 
Geology and Geophysics. 

ACKNOWLEDGEMENTS 

Dr. Dorothy Hill, University of Queensland, 
Brisbane, supplied a list of 18 papers contain- 
ing data on the Palaeozoic corals in the Pacific 
region. The most significant paper published 
in the period under review is Dr. Hill's president- 
ial address to Section C of the A.N.Z.A.A.S. 
Meeting in Dunedin in January, 1957 (Hill, 
1957). She has also prepared for the Bangkok 
Congress a paper on "Circum- or Trans-Pacific 
Correlation of Palaeozoic Coral Faunas." 

Miss Irene Crespin, Bureau of Mineral 
Resources, Canberra, has sent me a long list of 
papers on foraminiferal studies in Australia, on 
the Cambrian System in Australia, and on 
Australian stratigraphy which bear on Pacific 
problems. From this material I have included 
17 items. 

W. Storrs Cole, Cornell Univeristy, forwarded 
six titles on foraminifera. 

Kiyoshi Asano, Tohoku University, Sendai, 
supplied a list of papers published by himself 
and his colleagues on foraminifera. Further 
Japanese references were provided by Teiichi 
Kobayashi, University of Tokyo. 

J.A. Jeletzky, Geological Survey of Canada, 
has supplied information on current work on 
the Belemnites. 

26 



Edwin L. Hamilton, U.S. Navy Electronics 
Laboratory, San Diego, and M.F. Glaessner, 
The University of Adelaide, have also helped in 
this compilation. All these colleagues were 
invited by me to join a Standing Committee set 
up at the Seventh Pacific Science Congress in 
New Zealand in 1949, but the Committee never 
functioned as such and has since been discon- 
tinued. However I am deeply indebted to them 
for responding to an appeal to help in bringing 
the bibliographies of my earlier report (Allan, 
1956) up-to-date. 

BIBLIOGRAPHY, 1953-1957. 

Allan, R.S., 1956, Report of the Standing 
Committee on Datum-planes in the 
Pacific Region. Proc. Eighth Pacific 
Sci. Congr., 1953, 2: 325-423. 

Arkell, W.J., 1956, Jurassic Geology of the 
World. Oliver & Boyd, Edinburgh. 
XV + 806 pp., 46 pis. 

Asano, K., 1953, Miocene Foraminifera from the 
Shintotsugawa Area, Kabato-gun, 
Hokkaido. Trans. Proc. Pal. Soc. 
Japan, N.S., 10 : 45-54, 1 pi. 

, 1953, Miocene Foraminifera from 

the Honya Shale, Joban Coal-field. 
Trans. Proc. Pal Soc. Japan, N.S., 
11:55-59, pi. 1. 

, 1953, Miocene Foraminifera from the 

Noto Peninsula, Ishikawa Prefecture. 
Short Pap., Inst. Geol. Pal Tohoku 
Univ., 5: 1-21, pis. 3. 

, 1953, Oligocene Foraminifera from 

Utsunai, Tonbetsumura, North Hok- 
kaido, ibid., 5 : 22-24, pi. 1. 

Banks, M.T., 1956, The Middle and Upper 
Cambrian Series (Dundas Group and 
its correlatives) in Tasmania. Intern. 
Geol. Congr. XXth sess. Mexico, Symp. 
Cambrian, 2 : 165-212. 

Basse, E., 1953, L'Extension des Kossmaticeras 
dans les mers Antarctico-indo-paci- 



fiques au neocretace. Proc. 1th Pacific 
Set. Congr. ,2 : 130-5. 

Browne, I. A., 1954, A Study of the Tasman 
geosyncline in the region of Yass, 
New South Wales. Journ. & Proc. 
R.S.N.S. Wales, 88(1) : 3-11. 

Campbell, J.D., 1955, The Oretian Stage of 
the New Zealand Triassic System. 
Trans. R.S.N.Z., 82 (5) : 1033-1047. 

and I.C. McKellar, 1956, The Otapi- 

rian Stage of the Triassic System of 
New Zealand Part I. Trans. R.S.N.Z., 
83 (4): 695-704. 

Cloud, P. E. J., 1956, Provisional Correlation 
of Selected Cenozoic Sequences in the 
Western and Central Pacific. Proc. 
Eighth Pacific Sci. Congr., 1953, 2: 
555-573, pi. 1. 

and Cole, W.S., 1953, Eocene Fora- 

minifera from Guam, and their implica- 
tions. Science, 111 : No. 3039, 323-24. 

Cole, W.S., 1954, Larger Foraminifera and 
smaller diagnostic Foraminifera from 
Bikini drill holes. U.S. Geol. Surv., 
Prof. Paper 260-0, 569-608, pis. 204- 
222. 

and Bridge, J., 1953, Geology and 
Larger Foraminifera of Saipan Island. 
U.S. Geol. Surv. Prof. Paper 253,45 pp., 
15 pis. 

Crespin, I., 1953, Lower Cretaceous Foramini- 
fera from the Great Artesian Basin, 
Australia. Contrib. Cushm. Fdn., 4 
(1): 26-36. 

, 1954, The Nelson Bore, South- 
western Victoria: Micropalaeontology 
and Stratigraphical Succession. Bur. 
Min. Resources Austral. Rep., 11. 

, 1954, Stratigraphy and Micropalae- 

ontology of the Marine Tertiary 
Rocks between Adelaide and Aldinga, 
South Australia. Bur. Min. Resources 
Austral. Rep., 12. 

Crespin, I., 1955, Bibliography of Australian 
Foraminifera. Micropalaeontology, 1 (2) : 
162-188. 

_, 1956, Fossiliferous Rocks from the 

Nullarbor Plains. Bur. Min. Resources 
Austral. Rep., 25 : 26-42. 

_ , 1956, Distribution of Lower Cretace- 
ous Foraminifera in Bores in the Great 
Artesian Basin, Northern New South 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

Wales. /. Roy. Soc. N.S.W., 89: 
78-84. 

_ , 1956, Notes on a Lepidocyclina 

bearing Rock from Cebu, Philippines. 

Bur. Min. Resources, Aust. Rep., 25: 

43-46. 
-, 1956, Migration of Foraminifera in 

Tertiary Times in Australia. Bur. 

Min. Resources, Aust. Rep., 25 : 1-15. 
, 1956, Changes in Ideas of Age of 

Certain Beds in the Australian Tertia- 

ries. Proc. Eighth Pacific Sci. Congr., 

1953, 2 : 515-522. 

Duncan, H., 1956, Ordovician and Silurian 
Coral Faunas of Western United States. 
Bull. U.S. Geol. Surv., 1021-F. 

Eames, F.E., 1953, The Miocene/Oligocene 
Boundary and the use of the term 
Aquitanian. Geol. Mag., 90 (6) : 388- 
292. 

Easton, W.H. and Gutschick, R.C., 1953, Corals 
from the Redwall limestone (Mississip- 
pian) of Arizona. Bull. S. Calif. Acad. 
Sci., 52 : 1-27. 

Fleming, C.A., 1957, The Genus Pecten in New 
Zealand. N.Z. Geol. Surv. Pal. Bull. 
26 :69pp., 16 pis. 

Fontaine, H., 1954, fetude et revision des 
Tabules et Heliolitides du Devonien 
d'Indochine et du Yunnan. Arch. 
Geol. Vietnam. 2 : 1-86, pis. 1-8. 
, 1955, Les Tabutes du Carbonifere 
et du Permien de Tlndochine et du 
Yunnan. Arch. Geol. Vietnam, 3 : 
65-81, pis. I-V. 

Fujimoto, H., 1956, The Carboniferous-Per- 
mian Boundary in Japan. Proc. Eighth 
Pacific Sci. Congr., 1953, 2 : 429-433. 

Glaessnei, M.F., 1953, Conditions of Tertiary 

Sedimentation in Southern Australia. 

Trans. R.S.S. Austral., 76 : 141-146. 
, 1953, Some Problems of Tertiary 

Geology in South Australia. J.R.S.N.S. 

Wales, 87 : 31-45. 

, 1953, Time-stratigraphy and the 

Miocene Epoch. Bull. G.S. Amer., 
64: 647-658. (Includes discussion of 
the "Letter Classification of Indonesia", 
pp. 654-656). 

and Wade, M., 1956, The Foramini- 
feral Genus Lepidocyclina in South 
Australia. Aust. J. Sci., 18 (6) : 220. 

27 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Gery, R.R., 1956, Eocene in the Philippines. 
Proc. Eighth Pacific Sci. Congr., 1953. 
2: 503-573. 

Hanai, T., 1953, Lower Cretaceous Belemnites 
from Miyako District, Japan. Jap. 
Journ. Geol. & Geogr.* 23: 63-80, pis. 
v-vii. 

Hanzawa, S., 1954, Notes on Afghanella and 

Sumatrina from Japan. Jap. Journ. 

Geol. & Geogr., 24: 1-14, pis. 1-3. 
-, 1954, Stratigraphical Distribution of 

the Fusulmid Foraminifcra in Japan. 

Intern. Geol. Congr., Alger (1952), Sec. 

13, Fasc. 15: 129-137. 
, 1957, Cenozoic Foraminifera of 

Micronesia. Geol. Soc. Amcr. Mem. 

66, 163 pp., 41 pis. 

Hill, D., 1954, Coral faunas from the Silurian 
of New South Wales and the Devonian 
of Western Australia. Bull. Bur. Min. 
Res., Geol. & Geophvs., 23: 1-51, pis. 
1-4. 

^ 1954^ Devonian corals from Waratah 

Bay, Victoria. Proc. R.S. Viet., 66: 
105-118, pis. 6-9. 

, 1955, Ordovician Corals from Ida 

Bay, Queenstown and Zeehan, Tas- 
mania. Pap. Proc. R.S. Tax., 89: 237- 
254, pis. i-iii. 

, 1955, Contributions to the Correla- 
tion and Fauna of the Permian in Aus- 
tralia and New Zealand. Journ. Geol. 
Soc. Australia, 2: 83-107. 

, 1956, Paleozoic Corals from New 

Zealand. Part I. The Devonian Corals 
of Reefton, New Zealand. N.Z. Geol. 
Surv. Pal. Bull. 25: 5-14, pis. 1-2. 

, 1957, The Sequence and Distribution 

of Upper Palaeozoic Coral Faunas. 
Austral. J. Sci., 19 (3a): 42-61. 

Hornibrook, N. de B., 1953, Faunal Immi- 
grations to New Zealand; 1, Immigra- 
tion of Foraminifera to New Zealand in 
the Upper Cretaceous and Tertiary. 
N.Z. Journ. Sci. & Techn., Sec. B, 
34 (6): 436-44. 

Ichikawa, K., 1956, Triassic Biochronology of 
Japan. Proc. Eighth Pacific Sci. Congr., 
1953, 2: 437-442. 

Ikebe, N., 1956, Cenozoic Geohistory of Japan. 
Proc. Eighth Pacific Sci. Congr., 1953, 
2: 446-452. figs. 

28 



Imlay, R.W., 1956, Stratigraphic and Geographic 
Range of the Early Cretaceous Ammonite 
Homolsomites. Journ. Paleont., 30 (5): 
1143-1146, pi. 120. 

Jeffords, R.M., 1955, Septal arrangement and 
ontogeny in the Porpitid Corals. Paleont. 
Contr. Univ. Kansas, Coelenterata, 2: 
1-16, pis. 1-3. 

, 1955, Mississippian Corals from New 
Mexico and a related Pennsylvanian 
species. Paleont. Contr. Univ. Kansas, 
Coelenterata, 3: 1-12, pis. 1-2. 

Kanmera, K., 1954, Fusulinids from the Upper 
Permian Kuma formation, southern 
Kyushu, Japan, with special reference 
to the fusulinid zone in the upper Per- 
mian of Japan. Mem. Fac. Sci. Kyushu 
Univ., Ser. D, 4: 1-38, 6 pis. 

Kawada, S. and Morikawa, R., 1953, So-called 
Parafusulina? japonica and its strati- 
graphical significance. Nat. Sci. & Mus. 
(Tokyo, Nat 1. Sci. Mus.) 20 (1-2): 1-7. 
(Jap., Engl. summ.). 

Kicinski, F.M., 1956, Note on the Occurrence 
of some Tertiary larger Foraminifera 
on Bouganville Island. Bur. Min. 
Resources Austral. Rep., 25: 76-77. 

Kobayashi, T., 1955, The Ordovician Fossils 
from the McKay Group in British Co- 
lumbia Western Canada: with a Note 
on the Early Ordovician Palaeogeo- 
graphy. Journ. Fac. Sci. Univ. Tokvo, 
Sect. 2, 9 (3). 

Kummel, B. and Lloyd, R.M., 1955, Experi- 
ments on Relative Streamlining of 
Coiled Cephalopod Shells. Journ. 
Paleont., 29 (I): 159-170. 

Ladd, H.S. et a/., 1953, Drilling on Eniwetok 
Atoll. Bull. Amer. Assoc. Petrol. Geol., 
37 (10): 2257-2280, 2 pis. (A note on 
correlation by W.S. Cole on p. 2272.) 

Leed, H., 1956, Paleozoic Corals from New 
Zealand, Part 2. Permian Reef-build- 
ing Corals from North Auckland Penin- 
sula, New Zealand. N.Z. Geol. Surv. 
Pal. Bull. 25: 15-23, pis. 3-5. 

Ludbrook, N.H., 1957, Permian Foraminifera 
from South Australia. Austral. J. Sci., 
19(4): 161. 

Marwick, J., 1953, Faunal Migrations in New 
Zealand Seas during the Triassic and 
Jurassic. N.Z. Journ. Sci. & Techn., 
Sec. ft 34 (5): 317-21. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Matsumoto, T., 1956, The Characteristic Features 
of the Cretaceous System in the Japanese 
Islands. Proc. Eighth Pacific Sci. Congr., 
1953, II, 457-462. 

Miller, A.K. and Furnish, W.M., 1955, Aturias 
from Southern Chile. Journ. Paleont., 
29(3): 467-468, pi. 51. 

Minato, M., 1955, Japanese Carboniferous and 
Permian Corals. J. Foe. Sci. Hokkaido 
Univ., 9 (4): No. 2, 1-202, pis. 1-43. 

Opik, A. A., 1956, Cambrian Geology of Queens- 
land. Internal. Geol. Congr. xxth Sess. 
Mexico, Symp. Cambrian, 2: 1-24. 

, 1956, Cambrian Palaeogeography of 

Australia, ibid., 239-284. 

Fetters, V., 1955, Development of Upper Creta- 
ceous Foraminiferal Faunas in Colom- 
bia. Joun. Paleont., 29 (2): 212-225. 

Raggatt, H.G. andCrcspin, I., 1955, Stratigraphy 
of Tertiary Rocks between Torquay and 
Eastern View, Victoria. Proc. R.S. Viet., 
67 (1) : 75-142. 

Reynolds, M.R., 1953, The cainozoic Succession 
of Maslin and Aldinga Bays, South 
Australia. Trans. R.S.S. Austral., 76 : 
114-140. 

Schouppe A v. and Stacul, P. 1955, Die genera 
Verbeekiella Penecke, Timor phyllwn 
Gerth, Wanner ophyllum n. gen., Lopho- 
phyllidium Grabau aus dem Perm von 
Timor. PalaeonWgraphica, SuppL, 4(v): 
95-196, pis. 7-8. 

Silberling, N.J., 1956, "Trachyceras Zone" in 
the Upper Triassic of the Western 
United States. Journ. Paleont., 30 (5): 
1147-1153. 

Spath, L.F., 1953, The Upper Cretaceous 
Cephalopod Fauna of Graham Land. 
Sci. Rept. Falkland Is. Depend. Surv., 
No. 3, 60 pp. 

Sutherland, P.K., 1954, New Genera of Carbo- 
niferous Tetracorals from Western 



Canada. Geol. Mag., 91 : 361-371, pis. 
9-10. 

Teichert, C, 1953, Some Trans-Pacific Paleozoic 
Correlations. (Abs.) Bull. Geol. Soc. 
Amer., 64 (12) : 1516-7. 

, 1953, A New Ammonoid from the 

Eastern Australian Permian Province. 
Journ. & Proc. R.S.N.S. Wales, 87 (2) : 
46-50. 

and Glenister, B.F., 1952, Fossil 

Nautiloid Faunas of Australia. Journ. 

Paleont., 26 (5) : 730-752. 
Thomas, D.E. and Singleton, O.P., 1956, The 

Cambrian Stratigraphy of Victoria. 

Intern. Geol. Congr. XXth Sess. Mexico, 

Symp. Cambrian, 2 : 149-164. 
Tischler, H., 1956, A New Mississippian Tetra 

coral from Death Valley, California. 

./. Paleont., 30 : 110-112. 
Thompson, M.L., 1954, American Wolfcampian 

fusulinids. Univ. Kansas Paleont. Contr., 

Protozoa, 5: 1-226, pis. 1-52. 
Todd, R. and Post, R., 1954, Smaller Foramini- 

fera from Bikini drill holes. U.S. Geol. 

Surv., Prof. Paper 260-N, 547-568. 
Toomcy, D.F., 1954, A Bibliography of the 

family Fusulinidae. Journ. Paleont., 

28 : 465-484. 

, 1956, Addendum to a Bibliography of 

the Family Fusulinidae. Journ. Paleont., 

30 (6) : 1360-6. 
Vella, P., 1957, Studies in New Zealand Fora- 

minifera. Part II: Upper Miocene to 

Recent Species of the Genus Notoro- 

talia. N.Z. Geol. Surv. Pal. Bull 28 : 

42-58, pis. 1-3. 
Weiss, L., 1955, Foraminifera from the Paleocene 

Pale Grcda Formation of Peru. Journ. 

Paleont., 29 (1) : 1-21, pis. 1-6. 
Yale, H. and Suzuki, A., 1955, Second Occurrence 

of Colonial Corals of Devonian Type 

in Tyosen (Korea). Proc. imp. Acad. 

Japan, 31 : 355-359. 



29 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Symposium : Nature, Location, and Origin of the Circum-Pacific 

Continental Margin 

Convener : ROGER REVELLE (U.S.A.) 
A GENETIC CLASSIFICATION OF CONTINENTAL SHELVES 

WARREN C. THOMPSON 

U.S. Naval Postgraduate School, Monterey, California, U.S.A. 



INTRODUCTION 

The margins of all continents are bordered by 
a continuous submerged terrace whose width 
varies from less than one to over 700 miles (aver- 
age 40 miles), whose outer margin has depths 
varying from zero to greater than 250 fathoms 
(average 70 fathoms), and whose surface varies 
in relief from completely smooth to greater than 
300 fathoms. In spite of these wide variations 
over the earth as a whole, shelves within given 
areas possess well-defined similarities that permit 
them to be conveniently catalogued according to 
types. The distinctive topography of each type 
reflects in turn the primary phenomenon that 
has shaped it. 

The classification presented herein is an out- 
growth of the shelf types described by Shepard 
(1948). It was devised for the purpose of present- 
ing to students a genetically consistent and useful 
framework, based on current data and concepts, 
to which all shelves could be fitted and compared 
in a systematic way. Much of the information 
on shelf dimensions and sediments that is pres- 
ented in the classification has been drawn from 
Shepard. 

SOME BASIC CONSIDERATIONS 
REGARDING SHELF ORIGIN 

Before introducing the classification, some 
recent developments and some thoughts that 
bear on the origin of shelves will be presented. 
The discussion will be restricted to shelves in 
middle latitudes, which are best known and which 
provide the best preserved clues to the history of 
the continent margins. These comparatively 
uniform shelves have been under the dominating 
influence of waves and currents, and have been 
free of the complications of glaciation and atten- 
dent crustal warping under ice loading in polar 
latitudes, and of coral reef growth in the tropics. 

30 



WAVE EROSION OF THE SEA FLOOR 

Recent observations (Dietz and Menard, 1951, 
and others), supported by wave theory, have 
shown that wave action can effectively erode hard 
rock bottoms only in shallow water in and near 
the breaker zone. The depth of erosion is de- 
pendent upon the magnitude of the wave action, 
and on exposed coasts of the great oceans storm 
waves abrade the bottom only to an average depth 
of about five fathoms. Currents on the other 
hand do not erode hard rock bottoms except in 
narrow channels where strong tidal currents occur 
and locally on open shelves off points where 
unusually strong coastal currents sweep the 
bottom. Currents do, however, maintain non- 
depositional environments on many outer shelves 
by preventing the permanent settling of fine 
suspended sediment. 

The conclusion can be drawn that nearly every- 
where rock is exposed on the open shelf, sea level 
with its attendant wave action has stood within 
a few fathoms of that elevation. The fairly com- 
mon occurrence of rock on the outer margins of 
shelves, which seems to be distinctive of moun- 
tainous coasts, indicates accordingly that these 
shelves are essentially wave-beveled surfaces, last 
planed off in the surf zone by a glacial sea level. 

WAVE -CUT SHELVES 

The probable wave-cut structure of most 
shelves off mountainous coasts has been con- 
firmed for the Southern California shelves. There 
the thickness of superficial sediment and the shape 
of the underlying hard rock surface has been 
mapped by the writer (in preparation) nearly 
across the shelf near Santa Barbara using 
core-hole data, and by the oil industry (personal 
communication) in several areas between San 
Diego and Santa Barbara using a newly developed 
bottom-penetrating sonic sounder (the Marine 



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GEOLOGY AND GEOPHYSICS 



Sonoprobe). These studies show the shelf to be 
essentially a hard rock surface on which un- 
consolidated marine sediments lie as a thin veneer, 
generally having a maximum thickness of a few 
tens of feet on the inner half of the shelf seaward 
of the surf zone, and thinning out completely 
or to only a few feet at the shelf margin. The 
occurrence of rock exposed on the outer margins 
of many other shelves off mountainous coasts 
implies a similar shelf structure. 

In addition to the bedrock nature of these 
shelves, the common occurrence of marine ter- 
races at high elevations on the adjacent coast, 
and indeed the presence of mountains fronting 
the coast, all signify that a net emergence of these 
continent margins is occurring. It seems probable 
that as each successive glacial sea level has oscil- 
lated across these shelves, a thin layer of rock and 
superficial sediments has been chewed off so that 
a net loss of rock mass has resulted during the 
Quaternary Period. 

CONTROL OF SEDIMENTATION BY WAVES 

The depth to which waves control the deposi- 
tion of sediment is also restricted to within a few 
fathoms of the sea surface. Detailed studies of 
changes in the bottom profile accompanying 
varying wave conditions off an open sand beach 
in Southern California showed that nearly all 
bottom changes occurred in depths less than 5 to 
6 fathoms, but minor variations were recorded 
as deep as 12 fathoms (Inman and Rusnak, 1956). 

In many areas where rivers deliver large 
volumes of fine sediment to the coast a shoal 
terrace extends seaward from the river mouth. 
The control by wave action of the development 
of such a terrace was clearly demonstrated in the 
case of the modern marine delta of the Atchafa- 
laya River in the northern Gulf of Mexico, where 
a terrace about two fathoms deep has been built 
five miles across the shelf since 1 890 (Thompson, 
1955). The occurrence of similar terraces off 
many large rivers, such as the four-fathom terrace 
off the Amazon having a width of 25 miles, was 
first noted by Shepard (1948), who has since 
termed them delta-front platforms (Shepard, 
1956). The depths of the shoal platforms off 
large rivers range from about 2 to 6 fathoms, and 
are proportional to the magnitude of wave action 
in the water bodies into which they are built. 
There is little doubt that all are adjusted to present 
sea level. 

SEDIMENT-CONSTRUCTED SHELVES 

Off broad alluvial coastal plains for which 
seismic and well-log data are available, the shelf 



is shown to form the surface of a mass of conform- 
able Cenozoic and Mesozoic shallow-water 
sediments many thousands of feet thick. The 
sediment-constructed origin of these continent 
margins through long continued subsidence is 
evident. Their Quaternary history, on the other 
hand, is largely unknown, except in the northern 
Gulf of Mexico where the search for oil has 
spurred intensive study. There, except in the 
vicinity of the Mississippi River mouth, Quater- 
nary sediments do not appear to exceed a few 
hundred feet in thickness according to data pre- 
sented by Toulmin (1952) and Fisk (1944). 
A similar thickness is suggested for the American 
Atlantic Coast by data from Cooke (1936) and 
Swain (1947). 



The area around the Mississippi River mouth 
presents a striking exception, however. The 
Quaternary sediments there exceed 3000 feet in 
thickness, 600 feet alone having been deposited 
since the last interglacial period on the Prairie 
shelf margin according to Fisk and McFarlan 
(1955). These writers also show that the shelf 
margin in that area has been built seaward a 
maximum distance of 40 miles since the last inter- 
glacial, but that away from the delta the modern 
and interglacial shelf margins coincide. Shepard 
has pointed out that the Mississippi River, like 
the Nile and Niger Rivers, is unusual in that it has 
managed to build its modern delta completely 
across pre-existing shelves. 

Postglacial marine deposition on the outer 
shelf has been negligible in the northeastern Gulf 
of Mexico as evidenced by the occurrence of 
Pleistocene relict sediments there (Gould and 
Stewart, 1955), and in the northwestern Gulf 
Recent sediments appear to be generally on the 
order of ten feet thick (Greenman and LeBlanc, 
1956; McClelland, 1952). It is thus apparent that 
the shelf margin in the northern Gulf, except in 
the vicinity of the Mississippi Delta, was last 
molded by a near-glacial sea level. Its relatively 
shallow depth, which is typical of the shelf edge 
off large rivers, can be attributed to control of 
deposition by that sea level. 

The American Gulf and Atlantic Coasts have 
clearly received a net accumulation of sediments 
during the Quaternary Period, deposition having 
centered about the fluctuating shoreline of the 
past. Upbuilding of the inner shelf in the Gulf 
appears to have been accomplished largely by the 
construction of deltaic plains during the longer 
interglacial sea level stands when rivers had 
sufficient time to alluviate their courses com- 
pletely. On much of the Atlantic Coast upbuilding 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



of the inner shelf occurred by the deposition of 
strand and bay fades, indicating that stream 
filling generally was not completed there before 
sea level fell with the approach of each glacial 
period. Upbuilding of the outer shelf on both 
coasts has probably been accomplished mainly 
by the deposition of marine deltaic sediments off 
rivers and strand sediments in the interfluvial 
areas. Upbuilding did not occur without some 
wave planation accompanying transgressing 
sea levels. 

It is probable that other shelves off broad 
alluvial coastal plains have a similar Quaternary 
structure and history. It also seems likely, judging 
from the Mississippi Delta, that those areas where 
the shelf is being downwarped rapidly off river 
mouths are quite localized and occur only off 
rivers that transport unusually large volumes of 
sediment to the shelf in regions where it is not 
being conducted continually to oceanic depths 
via flow down submarine canyons. The latter 
situation may be occurring off the Congo River, 
incidentally. 

SEA LEVEL CONTROL AND STABILITY OF THE SHELF 
MARGIN 

Many lines of evidence point to the conclusion 
that the break-in-slope at the shelf margin was 
controlled by one or more glacial sea levels that 
remained stationary for a significant period of 
time at or near the elevation of the shelf break. 
The fairly common occurrence of rock and of 
relict sediments on the outer shelf have been men- 
tioned. The typically well-defined appearance 
of the break nearly everywhere and the continuity 
it displays also favor strand-line control. Further, 
the relatively uniform depth of the break agrees 
reasonably with the generally accepted estimates 
of the elevation of the Wisconsin sea level based 
on the probable volume of continental ice (Flint, 
1947). Finally, the projection seaward across ' 
the shelf of the late Quaternary pre-alluvial pro- 
files of some large rivers has shown that sea level, 
probably in late Wisconsin time, was at or near 
the shelf margin. 

Because shelf margins off mountainous coasts 
appear to be rock surfaces that have been little 
masked by marine sediment since planation by 
a glacial sea level, variations in the depth of the 
margin can be used to estimate maximum vertical 
displacement that has been experienced due to 
tectonic or isostatic activity since that time. 
These shelves range in depth from about 50 to 
100 fathoms, with a mean depth given by Shepard 
of about 80 fathoms. Consequently, the maxi- 

32 



mum vertical displacement has nowhere exceeded 
about 30 fathoms from the mean elevation; 
whereas, sea level has risen about 80 fathoms from 
that elevation (assuming no significant uplift or 
depression of these shelves as a whole to have 
occurred). Assuming that sea level was near the 
shelf edge in late Wisconsin time some 12,000 to 
20,000 years ago, the maximum rate of vertical 
shelf movement has amounted to 10 to 15 feet 
per 1000 years. 

Estimates of shelf movement off deltaic coastal 
plains must be based on coring data from the 
outer shelf in order to unravel recent sedimentary 
history, consequently these are available only for 
the northern Gulf of Mexico. According to 
Fisk and McFarlan, the late Wisconsin shelf 
margin in the vicinity of the Mississippi Delta 
has been downwarped more than 500 feet, giving 
an average rate of 25 to 40 feet per 1000 years. 
However, elsewhere in the northern Gulf it is 
evident from the depth of the shelf margin and 
the thickness of Recent marine sediments that 
the shelf has experienced much slower vertical 
movements. Other evidence relating to the 
stability of shelves in middle latitudes and in the 
tropics have been reviewed briefly by Kuenen 
(1955). 

Because glacial sea level fluctuations have 
exceeded considerably the rates of vertical move- 
ment of nearly all shelves during much of the 
Quaternary period, the oceans can be visualized 
as having periodically encroached upon and 
receded from the comparatively stationary con- 
tinent margins nearly everywhere, swinging 
through a full range generally estimated at 450 
to 650 feet. 

SUBMARINE CANYONS IN RELATION 10 SHELF 
HISTORY 

Because of the intimate association of sub- 
marine canyons and continental shelves, some 
pertinent concepts and observations regarding 
canyon origin will be discussed. For a general 
review of arguments on canyon origin, the reader 
is referred to the works of Kuenen (1950) and 
Shepard (1948). 

There is impelling evidence that nearly all 
submarine canyons owe their origin entirely to 
marine processes, having been carved into the 
continental slopes and shelves by the flow of 
turbidity currents down their axes. The heads 
of some canyons may have been modified by 
subaerial erosion during exposure on the shelf 
accompanying glacial sea levels, however 
Shepard, 1949). There appears to be at least 



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GEOLOGY AND GEOPHYSICS 



three conditions that must be met for canyon 
initiation and cutting: (1) a permanent sediment 
supply to the coast, (2) continual reservoiring 
of the sediment in the same location, where it 
repeatedly accumulates until unstable, then slides 
away, and (3) a steep slope down along which the 
sliding may take place. In addition, it is probable 
the sediment should have a considerable fraction 
that of sand-sized material. It is apparent that 
these conditions have occurred only during periods 
when sea level lay at or near the shelf margin. 

It seems incongruous that submarine canyons, 
which are clearly erosional features, should cut 
sediment-constructed continent margins. How- 
ever, Fisk and McFarlan give a consistent ex- 
planation of how this may come about in the case 
of the now dormant Mississippi Canyon. There, 
cutting appears to have occurred only during the 
period when coarser sediments, such as were 
transported by all rivers as a consequence of 
increased gradients during glacial sea levels, were 
carried directly to the shelf edge. During low sea 
levels, but prior to and following canyon cutting 
when sediments were not being carried directly to 
the shelf edge, hundreds of feet generally finer 
sediment blanketed the slope and shelf. 

The canyons on the broad shelf off the 
American Atlantic Coast also are clearly related to 
rivers on land. They were likewise eroded only 
during glacial sea levels, and have been left 
stranded on the outer shelf to remain dormant 
until the time when sea level may fall again. 

In contrast, the canyons along the California 
Coast have cut almost completely across the 
narrow shelf and head near shore where they trap 
beach sand being transported along the coast by 
longshore currents (Crowell, 1952). Some show 
no relationship to land drainages, modern or 
ancient, and were initiated during a glacial sea 
level probably by the accumulation of longshore 
drift behind major points which acted to reservoir 
sand at the brink of the continental slope. 
Headward erosion has kept pace with rising sea 
level so that many of these canyons are 
active today. 

Submarine canyons have a variety of ages. 
Most appear to be products of the Pleistocene 
Epoch, but some that are related to large-scale 
physiography of the coast, like the Monterey 
Canyon, may have originated in Tertiary time. 
Others have been excavated only as recently as 
the Late Wisconsin, as in the case of the Missis- 
sippi Canyon (Fisk and McFarlan, 1955). There 



is no doubt, however, that erosion of all canyons 
proceeded extremely rapidly during the Pleisto- 
cene glacial maxima. 

TOPOGRAPHY OF 
CONTINENTAL SHELVES 

AGE OF SHELF TOPOGRAPHY 

It is evident from the foregoing discussion that 
the topography of modern shelves reflects the 
history of many events that have occurred over 
a wide spectrum of time extending from the pres- 
ent back into the past. In general, the smallest 
features that can be observed are youngest and 
the largest oldest. 

Minor features, such as individual rocks and 
depressions, submerged terraces, tidal-scour 
channels, beach deposits, etc., and a few larger 
features, such as barrier reefs and coral banks, 
were formed only during the most recent major 
glacial oscillation of sea level. These will be 
partially or completely eliminated by erosion or 
burial if sea level will again experience a fluctu- 
ation of amplitude similar to the last. 

Most large-scale topographic features on the 
shelves took longer to form, and existed prior 
to the most recent glacial cycle. Some large river 
valleys show evidence of having been cut and filled 
through several major sea level oscillations 
(Zeuner, 1950). Large glacial troughs on the 
shelves undoubtedly were scoured by ice re- 
peatedly in the Pleistocene. And some submarine 
canyons have been active periodically during 
glacial sea levels, although others have been 
enlarged by submarine erosion continuously since 
their inception. It is apparent, then, that nearly 
all topographic features on modern shelves are 
products of the Ice Ages, all having been either 
formed or last modified during the most recent 
major sea level cycle. 

Shepard has pointed out, in reference to shelves 
in middle latitudes, that the general width of 
shelves depends upon whether they lie adjacent 
to young mountain ranges, off which the conti- 
nental slope is notably steep, or adjacent to coasts 
with large rivers, and their more gentle con- 
tinental slope. It may also be observed that 
shelf widths off glaciated coasts in general bear 
a similar relationship to the relief of the coast. 
Thus the overall width of modern shelves reflects 
the general relief of the continent margins, which 
in many areas is clearly related to the gross geo- 
logic structure. The gross shape, then, has been 
acquired through an even longer period of time 
of mountain-building duration or longer. 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



In fact, contemplation of the nature of wave 
and current action in and near the surf zone 
leads one to the conclusion that shelves must 
have been maintained continuously off most 
coasts of the earth as long as there have existed 
well-defined ocean basins and continents. 

GEOLOGY OF THE CONTINENT MARGINS 

The continent margins can be considered to 
consist of two general types the relatively stable 
areas that include pre-Cambrian shields and 
continent platforms, and the unstable areas where 
thick accumulations of Mesozoic and Cenozoic 
sediments are experiencing active tectonic evolu- 
tion, as manifested by the presence of mountain 
ranges, or are undergoing extensive active sub- 
sidence, as is occurring off broad coastal plains. 

Most stable areas of the continents lie within 
a few hundred feet of sea level and form lowland 
coasts off which the shelf tends to be broad, such 
as off the Arctic coasts of Europe and Asia. 
However, some shield areas stand a few thousand 
feet above sea level and effectively form moun- 
tainous coasts, and there the shelves are typically 
narrower, as off Labrador and South Africa. 
Unfortunately the gross geology of the continen- 
tal shelves over most of the earth is unknown, 
particularly off stable coasts, so that it is impos- 
sible as yet to classify them on the basis of their 
geology. However, because shelf widths do bear 
a close relationship to the physical relief of the 
coast they are treated accordingly in the classi- 
fication that follows. 

SUPERFICIAL SHELF-SHAPING AGENCIES 

Four distinctly different agencies have helped 
shape shelves during the Quaternary Period as sea 
level has oscillated back and forth across the 
continent margins: (1) land ice, (2) ice at sea, 
(3) waves and currents, and (4) coral reef growth.* 
The magnitude of the relief and the nature of the 
sediments present on a given shelf have been 
determined largely by the character of the domi- 
nant agency that has been operating. 

Thus, the highly erratic character of erosion 
arid deposition by glacial ice in polar latitudes 
has produced a grossly irregular topography that 
in some areas has a relief exceeding 300 fathoms. 
This irregular surface undoubtedly did not exist 
on present shelves prior to the onset of the great 
Pleistocene glaciations, except possibly in certain 
restricted regions. 

In marked contrast, shelves in high latitudes 
that have not been glaciated commonly display 

34 



an irregular bottom having a relief of only a few 
fathoms, which appears to be caused by the 
grounding of sea ice in depths at least as great as 
several tens of fathoms. The topography and 
sediments of these shelves are also modified by 
the freezing of bottom materials into the sea ice 
near shore, and by their eventual rain over the 
bottom upon melting. 

Shelves which have been shaped dominantly 
by waves and currents associated with the 
swinging Pleistocene sea levels also display a 
relatively subdued topography, particularly off 
deltaic coastal plains. Their relief appears to be 
generally less than 10 fathoms, and depends upon 
the resistance of rocks to wave erosion, variations 
in sediment deposition, and recent tectonic 
activity. 

In regions where coral growth has been the 
dominant agency in shaping the shelf, differential 
reef growth over a late Wisconsin glacial platform 
since sea level has risen to its present elevation 
can account for the major relief of less than 50 
fathoms (from reef flat to lagoon floor) that has 
been observed in the case of nearly all coral 
shelves. In addition, because of the rapidity of 
coral growth, coral reef shelves have distinctively 
shoal margins that are adjusted essentially to 
modern sea level, in contrast to other shelves. 
For recent comprehensive discussions of these 
shelves, the reader is referred to Kuenen (1950) 
and Fairbridge (1950). 

The shelf-shaping agencies have been roughly 
latitudinally distributed in their effect upon the 
continent margins; consequently, it is convenient 
to refer to the associated shelves as polar, middle- 
latitude, and tropical shelves. 

GENETIC CLASSIFICATION 
OF SHELVES 

THE CLASSIFICATION 

A brief description of the history, topography, 
and sediments of each of the three basic shelf 
types is presented in the following outline. 
Because the appearance of modern shelves is 
primarily a product of the events of the last glacial 
cycle, the history will be reviewed only back 
through the late Wisconsin cycle. In addition, 
the effects of small-scale sea-level fluctuations 
associated with minor climatic variations, such 
as the Climatic Optimum, which probably have 
occurred throughout the existence of the oceans, 
will not be considered. 

The outline provides only a mean description of 
the continental shelves; wide variations from the 



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GEOLOGY AND GEOPHYSICS 



mean occur within each type. Shelves around 
oceanic islands and in isolated ocean-connected 
seas, as well as coral banks and atolls, may also be 
classified in the same way ; however, their average 
dimensions are generally smaller than those 
stated below. 

I. Polar Shelves High latitude shelves that have 
been modified by glacial ice or sea ice. 

A. Glaciated shelves Includes all shelves that 
have been covered by glacial ice in the Qua- 
ternary Period. 

1. History Following the last interglacial 
period, most shelves exposed during falling 
sea level were probably modified somewhat 
by river erosion and deposition. Glaciers 
and ice sheets then moved down river 
valleys and former glacial troughs to the 
glacial sea level, cutting deepest where the 
ice was thickest and the valley gradients 
steepest. Regional downwarpings occurred 
under ice load. With rising sea level ice 
disappeared on nearly all but Antarctic 
and Greenland coasts, leaving fjords and 
gulfs along the coast, deepened troughs and 
basins extending across the shelf, and 
banks on many outer shelves. 

2. Topography Extremely irregular, with 
glacial troughs, basins, and banks of large 
and small size. Some troughs extend more 
than 300 f. below the open shelf surface, 
and some fjords exceed a depth of 800 f. 
Width averages 100 mi., but varies from 
less than 10 to over 700 mi. Depth of the 
margin averages 112 f., but is highly vari- 
able. There is no typical profile. 

3. Sediments Probably largely glacial till 
irregularly distributed in highly variable 
thicknesses on a rock surface, and veneered 
with glacial marine sediments in many 
areas. Mud is common in basins and off 
large rivers, and wave and current 
winnowed sand occurs on shoal banks. 
Shorelines are commonly rocky and irreg- 
ular and beaches are meager and of 
varied texture. 

4. Sub-types 

a. Shelves off mountainous (rising) coasts 
Topographic relief is the most extreme 
of all shelves, and is the product of 
erosion by valley glaciers. The outer 
margin is typically interrupted by glacial 
troughs, and the coastline is the classical 



fjord type. Shelves are narrower than 
the average glaciated shelf. An example 
is the British Columbia shelf. 

b. Shelves off lowland (subsiding) coasts 
Gross topography was produced by an 
overriding ice sheet. Relief is more 
subdued and the shelf is broader. Gulfs 
and bays arc common but classical 
fjords are absent. An example is the 
Maine-Nova Scotia shelf. 

B. Non-glaciated shelves Includes all shelves 
that have not been overridden by glacial ice, 
but which were and arc being influenced by 
fast ice (both frozen to and grounded on the 
bottom or shore). Examples occur off the 
Bering Sea coast of Alaska and much of the 
Arctic coast of Siberia. 

1. History These shelves have been very 
little studied. They occur in regions where 
snow accumulation has been insufficient to 
produce glacial ice, and are restricted to the 
Northern Hemisphere. They are further 
restricted mainly to lowland coasts because 
most mountainous coasts in high latitudes 
have been glaciated. Large rivers com- 
monly drain the coasts. The gross history 
and structure of these shelves appears 
to be similar to that of the shelves off 
lowland coasts in middle latitudes. 

2. Topography The shelf profile is relatively 
smooth, in marked contrast to the glaciated 
shelf. However, large areas of the sea 
floor display small-scale irregular mounds 
and depressions having a relief of a few 
fathoms, which appear to be caused by sea 
ice grounding on the bottom in depths at 
least as great as several tens of fathoms 
relative to the contemporary sea level. 
Although large icebergs can ground in all 
depths across a shelf, they are very uncom- 
mon in the Arctic Ocean. 

3. Sediments Typically poorly sorted mud 
and sand of ice-rafted and river origin. 

II. Middle -latitude shelves Shelves that have 
been influenced dominantly by waves and 
currents. 

A. Shelves off mountainous (rising) coasts The 
following description is restricted to mount- 
ainous coasts in young orogenic belts such as 
ring much of the Pacific Basin ; however, the 
presence of mountains along older coasts such 
as the southwest African coast suggests a 
similar history and character. 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



1. History Falling sea level following the 
last interglacial period left behind a wave- 
planed rock terrace generally covered with 
a few feet of beach and littoral sediments. 
Variable thicknesses of alluvium accumu- 
lated on the upper parts of the terrace, and 
rivers universally embedded themselves in 
steep-sided valleys cutting across the 
terrace. During the glacial maximum all 
submarine canyons were actively enlarging 
and some new ones were formed near 
coastal points and off large rivers. With 
rising sea level, waves associated with the 
landward advancing shoreline beveled off 
the former shelf, commonly producing sea 
cliffs and leaving an elevated terrace. 
Rivers and streams alluviated their courses. 
Some submarine canyons became dormant 
as the sediment supply to the heads was cut 
off, but others remain active. Except off 
large rivers, only a thin blanket of Recent 
marine sediment has accumulated on the 
bedrock surface, the layer being thickest 
on the inner and central shelf. 

2. Topography Width averages 10 mi. and 
depth of margin averages 80 f. Typical 
profile is sharply concave near the shore- 
line, nearly flat in mid-shelf, gently convex 
on the outer shelf, and sharply convex 
at the shelf margin. Shelf surface is fairly 
smooth, with the relief of rocks, depres- 
sions, and terraces commonly not exceed- 
ing 10 f. General trend of the shelf margin 
and coastline is fairly smooth in contrast 
to glaciated shelves. Some bays occur 
where stream courses have not been com- 
pletely alluviated. Beaches are typically 
meager and discontinuous, and range in 
size from pocket beaches on up. Seacliffs 
typically form the coastline. 

3. Sediments The outer shelf is commonly 
a non-depositional environment and rock 
exposures and relict sand and coarse sedi- 
ments are common there. Rock is also 
common in the surf zone and along the 
shore. Mud is common on the inner and 
central shelf. Most beaches are sandy but 
cobble and boulder beaches also occur. 

B. Shelves off lowland (subsiding) coasts This 
description applies only to shelves off broad 
coastal plains that are known to form the sur- 
face of a thick subsiding sediment mass. 
These coasts are typically the loci of large 
rivers. The structure, hence the history, of 



shelves off other lowland coasts, such as that 
off French West Africa, is essentially un- 
known. 

1 . History The Quaternary history of most 
coastal plain shelves differs from that of 
mountainous coasts in that these shelves 
appear generally to have experienced a net 
accumulation of material rather than a net 
loss. During the last interglacial period 
when the oceans stood at a high level for 
a period of time, former entrenched valleys 
on some coasts (e.g., the northern Gulf of 
Mexico) were generally alluviated com- 
pletely and broad deltaic plains were sub- 
sequently constructed across the inner 
shelf. Off other coasts (e.g., the eastern 
United States) alluviation was incomplete, 
and littoral and brackish bay sediments 
were deposited. With falling sea level, 
rivers entrenched themselves and trans- 
ported larger sediment loads and coarser 
textures. Marine deltaic deposits accu- 
mulated off river mouths and strand 
deposits formed between to build up the 
shelf, across which sea level subsequently 
progressed. The exposed terrace ex- 
perienced mild erosion. When rivers 
debouched directly at or near the continent 
margin old submarine canyons were re- 
activated and new ones were formed. 
With rising sea level, submarine canyons 
became dormant and river courses were 
alluviated, although incompletely in most 
cases so that estuaries and bays formed. 
Superficial wave planation by the advan- 
cing shoreline commonly occurred, leaving 
behind a veneer of littoral marine sedi- 
ments. Some rivers completely filled their 
channels and are currently building deltaic 
plains across the shelf. Apparently 
unique conditions have prevailed off some 
large rivers like the Mississippi that carry 
unusually large sediment loads. There, 
great thicknesses of sediment have accu- 
mulated locally, accompanied by rapid 
local downwarping of the shelf. 

2. Topography Width averages perhaps 
75 mi., except where large rivers have built 
deltas across the shelf (e.g., Nile, Niger, 
Mississippi), and where cuspate forelands 
have formed (e.g., Cape Hatteras on At- 
lantic Coast of United States). Depth of 
shelf margin averages 60 f. Profile is 
similar to that off mountainous coasts 
but is more subdued. Relief typically 



36 



does not exceed a few fathoms. Trend of 
shelf margin and of open coastline between 
major points is very smooth. Long barrier- 
island chains commonly form the open 
coast, inside of which occur large bays and 
estuaries. 

3. Sediments Hard rock outcrops are not- 
ably absent. Sand is common on the shelf, 
but mud predominates in the vicinity of 
rivers. Beaches are typically sandy, 
although extensive mud beaches occur 
adjacent to some large rivers. 

III. Tropical shelves Shelves in low latitudes 
that have been modified by coral reef growth 
(coral shelves composed in part of calcareous 
oolite, like that off western Florida, are 
included). 

A. History During the last interglacial period 
reefs were probably built to a high sea level 
much as they are today. Falling sea level 
exposed reefs, including the Pacific oceanic 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

atolls and the Bahamian platforms, to the 
destructive processes of solution, denudation, 
and wave erosion, which eventually lowered 
them approximately to the elevation of the 
late Wisconsin sea level. At the same time, 
peripheral reef growth widened the coral 
platform. With the subsequent rise of the 
oceans the reef margins grew upward rapidly 
to form barrier reefs enclosing lagoons. 
Lagoon floors have since been built upward 
somewhat by coral growth and by the accu- 
mulation of calcareous debris and detritus. 
In many areas reefs have grown upward on 
non-coralline shelf surfaces of late Wisconsin 
age. 

B. Topography Width is typically highly vari- 
able and often difficult to define, the widest 
shelf being 125 mi. across in eastern Australia. 
Depth of the margin is less than 20 f. nearly 
everywhere, and generally only a few fathoms. 
Major topography, typically consisting of 
a barrier and fringing reef separated by a 




Fig. 1. Distribution of continental shelf types. The long dashed boundaries are uncertain. The short dashed 

line represents the shelf margin. 

37 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



lagoon, is irregular with a relief averaging 
about 25 f. and generally not exceeding 50 f. 
Minor topography is typically very irregular 
and includes such features as coral heads, 
negro heads, reef-edge notches, and boat 
channels. The shelf margin is commonly 
marked by a precipitous drop-off or a steep 
talus slope. Beaches are typically meager. 

C. Sediments Reefs are largely coral rock 
masses, but some reefs are sand-covered and 
some are bordered with boulder ramparts 
along the seaward margin. The floors of 
lagoons and depressions are of calcareous 
sand or mud. Beaches are typically coral 
sand but shingle beaches also occur. Where 
reefs have been built on non-coralline shelves, 
inorganic clastic sediments are also present. 

DISTRIBUTION OF SHELF TYPES 

The distribution of shelf types is shown in the 
attached figure. The boundaries of the glaciated 
shelves in the Northern Hemisphere follow essen- 
tially the limits of maximum Pleistocene glaciation 
presented by Flint (1947). The boundaries of 
the non-glaciated polar shelves were derived from 
data on the present distribution of sea ice (Hydro- 
graphic Office, 1946) and the present trend of 
winter isotherms (minimum monthly) over ocean 
and land areas (Sverdrup, 1943; Haurwitz and 
Austin, 1944). The boundary of the polar shelves 
in the Southern Hemisphere follows the general 
trend of modern winter isotherms. The boun- 
daries of the tropical shelves follow the sea surface 
isotherm of 18C in the coldest winter month, 
which determines the approximate geographical 
limit of modern coral reef growth. The shelf 
boundaries shown in the figure have been 
extended across the deep oceans and across land 
areas mainly for the sake of continuity, although 
they do serve to classify the shelves around islands - 
and in inland seas. 

It should be pointed out that the boundaries 
between shelf types shown in the figure are not 
everywhere clearcut. Thus, the boundary between 
middle-latitude and tropical shelves is typically 
gradational, which reflects the variability of the 
distribution of favorable living environments for 
reef-building corals near the geographical limits of 
reef growth. The boundaries of glaciated shelves 
on the other hand are generally well-defined, and 
can be distinguished readily on bathymetric 
charts in most regions. 

Shelf types likewise are not pure forms within 
the areas shown in the figure. For example, 

38 



middle-latitude mountainous coasts are com- 
monly interrupted by large valleys or locally 
fronted by narrow plains off which the shelf 
characteristics tend toward those of the middle- 
latitude lowland coast. An example is the Oxnard 
Plain in California which is drained by the Santa 
Clara River. Shelves off middle-latitude coastal 
plains, on the other hand, are typically pure 
examples of the lowland shelf type along the 
entire length of the coastal plain. 

Coral reef shelves are particularly heteroge- 
neous, reefs in many areas commonly occurring 
as a patchwork in an otherwise non-coralline 
environment. Also, great stretches of coast in 
the tropics do not support reefs, particularly in the 
vicinity of large rivers. Thus the shelves along 
much of the west and north sides of the Indian 
Ocean and adjacent to the Amazon Delta are 
actually middle-latitude types. Because of the 
very irregular and incompletely known distri- 
bution of coral reefs, no attempt has been made 
in the figure to distinguish between those tropical 
shelves that do and do not support them. For 
details of the world-wide distribution of reefs the 
reader is referred to Joubin (1912). 

The polar Siberian shelf that is classified as 
non-glaciated in the figure may also be a compo- 
site shelf. According to the world map issued by 
the National Geographic Society in March 1957, 
the shelf margin is interrupted by a number of 
indentations strongly suggestive of a glacial 
origin. Also, the sparsely mapped shelves of the 
Berents and Kara Seas may be non-glaciated in 
part. Flint believes that shelf ice extended into 
these seas from the surrounding land areas during 
Wisconsin time, but that the deeper central parts 
were not overridden by ice. 

CLASSIFICATION OF COASTS AND SHORELINES 

Coasts and shorelines are products of the same 
agencies that have shaped the shelves, and con- 
sequently they can be classified genetically on 
a worldwide basis in the same manner as the 
shelves. The classification clearly differs from 
earlier ones (Johnson, 1919; Shepard, 1948), but 
its discussion is beyond the scope of this paper. 

REFERENCES 

Cooke, C.W., 1936, Geology of the Coastal Plain 
of South Carolina. U.S. Geol. Surv., Bull. 
867, 196 pp. 

Crowell, J.C., 1952, Submarine Canyons Border- 
ing Central and Southern California. 
Jour. Geol, 60: 58-83. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Dietz, R.S. and H.W. Menard, 1951, Origin of 
Abrupt Change in Slope at Continental 
Shelf Margin. Amer. Assoc. Petrol. GeoL, 
Bull. 35: 1994-2016. 

Fairbridge, R.W., 1950, Recent and Pleistocene 
Coral Reefs of Australia. Jour. GeoL, 
58: 330-401. 

Fisk, H.N., 1944, Geological Investigation of the 
Alluvial Valley of the J^ower Mississippi 
River. Miss. River Comm., Vicksburg, 
Miss., 78 pp. 

Fisk, H.N. and E. McFarlan Jr., 1955, Late 
Quaternary Deltaic Deposits of the 
Mississippi River. GeoL Soc. Amer., 
Spec. Paper 62: 279-302. 

Flint, R.F., 1947, Glacial Geology and the Pleisto- 
cene Epoch. John Wiley & Sons, New 
York, 589 pp. 

Gould, H.R. and R.H. Stewart, 1955, Continental 
Terrace Sediments in the Northeastern 
Gulf of Mexico. Soc. Econ. Paleon. and 
Mineral., Spec. Pub. 3: 2-20. 

Greenman, N.N. and R.J. LeBlanc, 1956, Recent 
Marine Sediments and Environments 
of Northwest Gulf of Mexico. Amer. 
Assoc. Petrol. GeoL, Bull., 40: 813-847. 

Haurwitz, B. and J.M. Austin, 1944, Climatology. 
McGraw-Hill, New York, 410 pp. 

Hydrographic Office, 1946, Ice Atlas of the North- 
ern Hemisphere. Navy Department, 
Wash., D.C., H.O. 550: 105 pp. 

Inman, D.L. and G.A. Rusnak, 1956, Changes 
in Sand Level on the Beach and Shelf 
at La Jolla, California. Beach Erosion 
Board, U.S. Corps of Engrs., Tech. 
Memo. 82: 30 pp. 

Johnson, D.W., 1919, Shore Processes and Shore- 
line Development. John Wiley & Sons, 



New York, 584 pp. 

Joubin, L., 1912, Banes et Recifs de Coraux 
(Madrepores). Annales Inst. Oceanogr., 
4. 

Kuenen, Ph. H., 1950, Marine Geology. John 
Wiley & Sons, New York, 568 pp. 

Kuenen, Ph. H., 1955, Sea Level and Crustal 
Warping. GeoL Soc. Amer., Spec. Paper 
62: 193-204. 

McClelland, B., 1952, Foundation Investigations 
for Offshore Drilling Structures in the 
Gulf of Mexico. Amer. Soc. Civil Engr., 
Convention Preprint Paper No. 16, New 
Orleans Convention, March 5-7, 1952, 
18pp. 

Shepard, F.P., 1948, Submarine Geology. Harper 
& Bros., New York, 348 pp. 

Shepard, F.P., 1949, Terrestrial Topography of 
Submarine Canyons Revealed by Diving. 
GeoL Soc. Amer., Bull., 60: 1597-1612. 

Shepard, F.P., 1956, Marginal Sediments of Mis- 
sissippi Delta. Amer. Assoc. Petrol. 
GeoL, 40: 2537-2623. 

Sverdrup, H.U., 1943, Oceanography for Mete- 
orologists. Prentice-Hall, New York, 
235 pp. 

Swain, F.M., 1947, Two Recent Wells in the 
Coastal Plain of North Carolina. Amer. 
Assoc. Petrol. GeoL, Bull., 31:2054-2060. 

Thompson, W.C., 1955, Sandless Coastal Terrain 
of the Atchafalaya Bay Area, Louisiana. 
Soc. Econ. Paleon. and Mineral., Spec. 
Pub. 3: 52-77. 

Toulmin, L.D., 1952, Volume of Cenozoic Sed- 
iments in Florida and Georgia. GeoL 
Soc. Amer., Bull., 63: 1165-1176. 

Zeuner, F.E., 1950, Dating the Past. Methuen 
& Co., London, 2nd edit., 474 pp. 



39 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



SEDIMENTS OF SHALLOW PORTIONS OF EAST CHINA SEA 

AND SOUTH CHINA SEA 



K. O. EMERY 

University of Southern California, Los Angeles, California, U.S.A. 
and 

HIROSHI NIINO 

Tokyo University of Fisheries, Tokyo, Japan. 

(Abstract) 



Nearly 1000 bottom samples from the shallow 
portions of the East and South China Seas were 
studied and compared with sources and ocean- 
ographic conditions. Sediments of the Gulf of 
Pohai and Central Yellow Sea are fine grained, 
low in calcium carbonate, and contain many 
unstable minerals and a moderately high percen- 
tage of organic matter. They are contributed by 
the Hwangho, Yangtze, and many smaller rivers. 
In the absence of strong currents they have formed 
a thick blanketing deposit that constitutes a 
modern zeugogeosyncline. The sediments on the 
west consist largely of reworked loess. 

Sediments of the inner half of the continental 
shelf between Shanghai and Hainan and in the 
Gulf of Tonkin are similar to those of the Central 
Yellow Sea and represent modern detrital 
materials contributed to the continental shelf by 
many rivers, but so far in amounts insufficient to 
completely cover the shelf. Seaward of these 
sediments, on the outer half of the continental 
shelf between Korea and Hainan is a broad belt 
of coarse sandy sediment from which finer sedi- 
ments are winnowed away or prevented from 
being deposited by the strong Kuroshio Current. 
The sediment contains glauconite and much 



calcium carbonate in the form of foraminiferal 
tests and broken mollusk shells but very little 
organic matter. Because the detrital portion is 
much coarser than that nearer shore, it is be- 
lieved to constitute a littoral deposit left from a 
Pleistocene time of glacially lowered sea level. 
Locally on the shelf are small areas of residual 
sediment near rock outcrops and usually con- 
taining reworked fossils. Occasional pieces of 
pumice and many small shards of volcanic glass 
are present in the sediments but nowhere are 
they abundant enough to form a true volcanic 
sediment. The shelf sediments are similar in 
most respects to those on the shelves of California 
and they clearly indicate temporary conditions 
below present base levels of equilibrium not 
epicontinental sea deposits. 

Seaward of the shelf edge, in deep water of the 
continental slope, the sediments become finer 
grained and contain more calcium carbonate, 
mostly from foraminiferal tests. These sedi- 
ments consist of the finergrained terrigenous 
material that by-passes the shelf and is deposited 
so slowly in the quiet deep water that Foramini- 
fera make up a large percentage of the total 
sediment. 



40 



VOLUME 12 GEOLOGY AND GEOPHYSICS 



SUBMARINE VALLEYS OF THE PACIFIC MARGIN 

F, P. SHEPARD 

Scripps Institution University of California, U.S.A. 

The paper was presented with illustrations at tion Committee, and no instruction has been 
the meeting, but was not handed to the Publica- received up to the time of going to press. 

Editor 



41 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PRESENT-DAY VERTICAL MOVEMENTS OF FAR EASTERN 
SEACOASTS OF THE USSR 

V. 1. BUDANOV, A. S. IONIN, P. A. KAPLIN, V.S. MEDVEDEV, 

and 
A. T. VLADIMIROV 

Institute of Oceanohgy, Academy of Sciences of the USSR, Moscow, USSR. 



PRESENT-DAY VERTICAL MOVEMENTS 

OF FAR EASTERN SEACOASTS 

OF THE USSR. 

Paleogcographical constructions, including the 
reconstructions of the ancient coastlines, the 
correlation of the quarternary marine deposits 
as well as some problems of modern dynamics 
of the sea coasts can only be solved correctly if the 
direction and speed of the vertical movements 
of the coasts in the past and also at the present 
time is found out. 

The literature dealing with the Pacific coasts 
contains a good many indications of the character 
of present-day and modern relative displacements 
of the coastline (Knappcn, 1929; Moffit, 1954; 
Valentin, 1954). These works contain not 
infrequently quite opposite views and opinions 
on the speed and direction of such displacements 
for the same regions of the coast (Okayama, 1931 ; 
Valentin, 1954). Such contradictory estimations 
can be apparently accounted for as follows: 

a) different explanation of the mechanism of 
formation of some parts of the coastal relief; 

b) imperfect method of research; c) slipshod 
demarcation of the signs of the modern and 
present-day vertical movements of the land. 

By present-day vertical movements the authors 
imply such movements which had occurred at 
the period of the formation of the present-day 
coastal relief, i.e. the relief of the underwater 
coastal slope to the depth of active action of the 
waves, of present-day coastal accumulative forms 
and the cliff. This period covers a few millen- 
aries and in general coincides with the historical 
time. Thus the present-day vertical movements 
of the coast zones are taking place as if it were 
"before the very eyes of the people". A good 
example of the present-day vertical coastal move- 
ments is furnished by the negative and positive 
movements of the earth crust in the region where 
the well-known ancient temple of Jupiter-Serapis 
(Italy) is situated. The present-day vertical 
movements strikingly manifest themselves in 

42 



Japan, where a number of fishing villages and 
ports found themselves removed from the sea, 
as a result of a rise of the land (Okayama, 1931). 

The raised or subsided marine terraces which 
are beyond the present coastal zone cannot be 
considered an indication of the present-day ver- 
tical movements of the coasts. They testify to 
earlier, modern displacements of the coastline. 

Repeated levelling is considered a most reli- 
able and precise method of exploring the vertical 
movements of the land. But this method neces- 
sitates specially organized work requiring much 
effort and long intervals between the periods of 
observation, which is often impossible to do on 
account of the remoteness and inaccessibility of 
the regions being explored. Therefore, the 
Soviet explorers most widely apply geomorpho- 
logical methods, of which the main one consists 
in an analysis of the structure of the marine ac- 
cumulative forms. They originate from a con- 
tinuous accumulation of clastic material and 
quickly react on the relative changes of the sea 
level. With a constant sea-level and a sufficient 
amount of clastic material the absolute heights 
of the beach ridges complicating the surface of 
the accumulative forms are approximately the 
same. If the sea-level was changing while the 
accumulative forms appeared (on condition of 
the homogeneousness of the clastic material and 
the constancy of the wave regime) the absolute 
heights of the beach ridges were changing ac- 
cordingly, from new to older ones (Johnson, 1919; 
Zenkovitch, 1948). Therefore an analysis of the 
profiles of the instrumental levellings of the sur- 
faces of the marine accumulative forms is the 
most reliable qualitative method of determining 
the present-day relative movements of the sea- 
coasts (Budanov, 195 la). 

The following data should be compared with 
those of the levellings : a) observation of the mor- 
phology and dynamics of the sea coasts, obtained 
as a result of direct exploration and of analysis 
of the material of aerial photography; b) the 
profiles of the underwater coastal slopes and other 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



material of the morphology of the coastal zone 
of the bottom (depth gauge, diving observations 
etc.); c) literary information, in particular, archae- 
ological data. 

This method of determining the present-day 
vertical movements of the coasts was worked out 
at the Laboratory of the dynamics and morpho- 
logy of the seacoasts, Institute of Oceanology, 
Academy of Sciences of the USSR, under the 
guidance of Professor V.P. Zehkovitch. This 
method has been applied by the authors during 
the explorations on the seacoasts of the Soviet 
Union, including those of Chukotka, the Bering 
Sea, the Sea of Okhotsk and the Sea of Japan 
(Budanov, 1951b; Budanov and lonin, 1956; 
Zenkovitch and Vladimirov, 1950; lonin, 1955). 

The material collected made it possible to obtain 
comparable results and to lay down the general 
character of present-day relative differentiated 
movements of the Far Eastern seacoasts. As to 
the direction of the present-day vertical displace- 
ments, the Far Eastern sea coasts are divided into 
a number of regions. Some of them are, accord- 
ing to available data, subsiding, others rising, 
and, finally, there are relatively stable regions 
without clearly expressed signs of any vertical 
movements. On the diagram-map (fig. 1) sub- 
siding, rising and stable regions as well as the 
points of levelling of the surfaces, of the marine 
accumulative forms are indicated by conventional 
signs. 

The coasts of Southern Sakhalin, of the 
Southern part of Primorye, of some regions of 
Eastern Kamchatka and the Koryak upland and 
also of the Western part of the Anadyr bay (fig. 1) 
may be called rising coasts. According to 
G.S. Ganeshin's data, the coasts of the Shantar 
Isles are rising, while the materials of V.I. Ly- 
marev's (1955) and V.F. Kanayev's (1958) re- 
search testify to a rise of the Great Kuriles. 

A lessening of the absolute height "of the beach 
ridges on the accumulative forms towards the 
shore-line, which has been ascertained by instru- 
mental levelling (fig. 2, a, b) is the most reliable 
sign of the present rise of the above-mentioned 
region of the sea coast. The beach ridges on the 
mid-bay bars and spits are well preserved. This 
is because in most cases the accumulative forms 
are made up of pebbles, rarer of sand-pebble 

Fig. 1 . Sketch Map of Present-Day vertical movement of 
Far Eastern Seacoasts of the USSR. 

1. Legend: Parts of insignificant relative rise, 

2. Parts of insignificant relative subsidence, 

3. Relatively stable parts of coasts, 

4. Places of instrumental levellings of the sur- 
faces of the marine accumulative forms. 



o .. 





43 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



and boulder material. In the Southern regions 
the beach ridges situated far from shore-line are 
not infrequently grown with turf. All this pre- 
cludes errors in determining the real heights of 
these forms, created by the sea, for they are 
practically not liable to cnanges worked by sub- 
aerial processes. 

The older beach ridges are relatively higher 
than the later ones on the rising coasts, this 
difference in heights varies widely. An instru- 
mental levelling of the surfaces of the marine 
accumulative forms has shown that this difference 
in height amounts to 1-2 m in the bays of Southern 
Primorye deeply cut in the dry land, to 2-2.5 m 
on the coasts of the Anadyr firth, to 3-3.5-4 m 
on the coasts of the Koryak upland and Sakhalin 
and even to 6.5 m in Kamchatka. Such a dif- 
ference in the heights of the beach ridges is not 
only a convincing proof of a rise of the land in 
these regions but it obviously shows its unequal 
speed in every region. 

Abrasion terraces well expressed in the relief 
of the bottom (fig. 3, a, b) are a characteristic 
feature of the morphology of the underwater 
coastal slope of the rising coast zones. As is 
known when the coast rises, new and old regions 
of the bottom which become open to the action 



of the waves are subject to abrasion. Therefore 
an abrasion platform with small slopes whose 
outer margin protrudes farther and farther into 
the sea is formed on the underwater coastal slope. 
However these underwater terraces on the rising 
coasts are not wide. Their rear parts are coming 
out from under the sea level, as a result of the 
rise, changing into above water terraces. These 
terraces, or, as they are often called "uplifted 
benches" (rock sections of the sea bottom with 
no debris) are bordering many abrasion sections 
of the coast within Sakhalin and the Kuriles. 

Owing to an extension of the underwater 
abrasion terraces and uplifted benches, abrasion 
on the rising coasts is usually retarded. Cliffs 
no longer touched by the waves are often to be 
found. Wave-cut niches raised to a considerable 
height and bearing clear traces of wave action 
(the Patience Peninsula on the Sakhalin, the 
Kuriles) if the coast is made up of durable 
rock may be observed on their surface. 

The appearance of peculiar relict accumulative 
forms on rock bases is caused by a rise of the 
coasts. Being formed on a higher sea -level they 
were fed mainly, thanks to a drifting of the debris, 
from the neighbouring abrasion regions. With 
the rise of the land and a dying away of the 








3500 



$000 



Fig. 2. Typical profiles of instrumental levellings of the surfaces of present marine accumulative forms, 
a, b Relatively raised coast profiles, 
c, d Relatively subsided coast profiles, 
e, f Relatively stable coast profiles. 

44 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




2000 



3000 




Fig. 3. Typical profiles of underwater'coastal slopes, 
a, b Relatively raised coast profiles, 
c, d Relatively subsiding coast profiles, 
e, f Relatively stable coast profiles. 

abrasion processes the amount of the clastic 
material in the coastal zone is decreasing, which 
causes erosion and a reconstruction of the ac- 
cumulative forms. Some of them are eroded 
completely, others owing to a rapid relative fall 
of the sea level are raised and isolated from the 
waves on the rock bases. 

The existence on some coasts of dried out 
lagoons may be noted among other signs of a 
rise of the above-mentioned regions. Such 
lagoons are most frequently to be found in the 
Anadyr Bay. The dried out parts of the lagoon 
bottoms usually border upon midbay-bars and 
are raised 0.5 m higher than the shore line. They 
are made up of modern marine deposits, the upper 
part of which is covered with a layer of lagoon 
slime, which makes it possible to judge for a rise 
of the coast. 

In natural conditions it is only a complex of 



signs which helps arriving at the conclusion of 
a rise of a certain region of the coast. Any of 
these signs taken separately can lead to an incor- 
rect inference. So, for instance, the speed of 
abrasion does not in itself allow to judge of a 
sign of the vertical movements, for an active 
destruction of the cliff by the waves may take 
place not only on subsiding coasts but in a number 
of cases in the places of a rise, provided there is 
a lack of debris in the coastal zone. One should 
also determine witn discretion the sign of vertical 
movements by hanging junctions to be met with 
on rising as well as subsiding coasts. The char- 
acter of the profile of the present-day accumul- 
ative form surfaces is to be considered the most 
reliable sign of a movement of the earth crust or 
sea-level. 

We observed the most pronounced traces of 
the present-day relative subsidence of the land in 

45 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



the Eastern and the Western parts of the 
Chukotka Peninsula, the North-Eastern part of 
the Koryak coast, some regions of the Eastern 
and Western coasts of Kamchatka and North- 
Eastern Sakhalin. 

A lessening of the absolute height of the beach 
ridges on the accumulative forms toward the land 
from newer to older ones, is the main indication 
of the present-day relative subsidence of the 
above-mentioned regions of the coasts. 

According to the data of instrumental levelling 
the heights of the old beach ridges differ from the 
newer ones by 1-2, 3-4 and, sometimes, even 
6-7 m (the latter figure refers to Western Kam- 
chatka), (fig. 2, c, d). Homogeneousness of the 
material, of which the accumulative forms are 
made up, proves that a lowering of the beach 
ridges with the removal from the shore-line, in 
the conditions of an open coast, cannot be caused 
by any change in the character of the clastic 
material supplied in the process of development 
to the beach ridges. This is the output of the 
relative subsidence of the land, which not infre- 
quently results in the older beach ridges of the 
rear parts of the accumulative forms being found 
lower than the present sea-level (Kamchatka, 
Sakhalin, etc.). 

The underwater coastal slope of the subsiding 
regions has no abrasion terraces expressed in the 
relief, (fig. 3, c, d). Such coasts are sometimes 
sunk to a considerable depth and buried under 
cover of the latest deposits. In the coastal part 
of the bottom there is usually a sloping concave 
abrasion surface with no debris. In the regions 
where moraine strata occur, their surfaces are 
covered with close set boulders and clods washed 
by the waves from the stratum of argillaceous 
grounds. At the present time these boulders and 
clods are overgrown with seaweeds, which proves 
their immobility even during strong storms. 
On the Western coast of Kamchatka and East of 
the Chukotka Peninsula the lower border of this 
so-called "boulder-clod bench" may be traced 
to a depth of 10-12 m. The presence of large 
clods and boulders, reaching 2 m in diameter 
can only be explained, at such a depth and so far 
removed from the coast, as a result of recession 
of the cliff and relative sinking of the coast. In 
another case, the heap of boulders and clods, 
as it is forming itself in front of the coasts, re- 
ceding due to abrasion, protects the cliff from the 
action ot the waves (Zenkovitch, 1949). 

An intense abrasion of very long rock regions 
of the coast as a result of which high (up to 200 m), 
46 



sometimes overhanging, cliffs are appearing, is 
an indirect sign of the present-day relative sub- 
sidence of a number of regions of the Far Eastern 
seacoasts. The peat bogs found during drilling 
in a number of areas of the Chukotka and Kam- 
chatka Peninsulas, situated lower than the present 
scale vel, is a still more striking sign of the 
subsidence. 

Lagoons are widespread on the subsiding coasts 
in the Far East (the Northern coast of the Chu- 
kotka Peninsula, Western Kamchatka, North- 
Eastern Sakhalin). Many of them are formed 
during the moving up of the storm-worked ridge 
upon the sloping surface of the plains at the foot 
of the mountains in the process of a slow sub- 
sidence of the land. A strip of the lowland, 
adjoining the rear of the beach ridge, often sinks 
lower than the sea-level and is flooded by the 
waters of the sea filtering through the ridge. The 
dimensions of the aquatoria of such lagoons are 
gradually increasing with the progressive sub- 
sidence of the coastal land. The described pro- 
cess of formation of the lagoons is also taking 
place at the present time and can be most clearly 
traced on the subsiding coasts of the Chukotka 
Peninsula (Zenkovitch, 1950; Kaplin, 1957). 

As is the case with the rising coasts, it is im- 
possible to determine the sign of the vertical 
subsiding movement according to one of the 
above-mentioned signs. Therefore, all the regions 
of subsidence marked on the diagram-map are 
indicated on the basis of a whole complex of 
geomorphological signs. 

At the present stage of geological history, some 
regions of the Far Eastern sea-coasts are in a 
relatively stable state (fig. 1). It seems that in 
such regions (Eastern coast ol the Bay of the 
Cross, central part of the Eastern coast of the 
Koryak upland, a number of regions on the 
coasts of Eastern Kamchatka and Western 
Sakhalin) the eustatic rise of the level of the World 
Ocean is compensated by an equal tectonic rise 
of the land. 

The signs of a relatively constant position of 
the sea-level in these regions of the coast are in 
many respects similar to those of a rise of the 
coasts, described above. With the help of instru- 
mental levelling of the surfaces of accumulative 
forms it becomes possible to establish the fact 
that all the beach ridges are approximately at 
the same height above sea-level. This makes it 
possible to arrive at a reliable enough conclusion 
on the stability of a certain region of the coast 
(fig. 2, e, f). 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Rather wide shallow abrasion terraces worked 
out by the waves in hard rock (fig. 3 c) and friable 
quarternary strata (fig. 3 f) are a distinguishing 
feature of the morphology of the underwater 
slope of the abrasion regions of the coast. These 
abrasion terraces possess the smallest surface 
slopes and their most intense working out is 
taking place until the very surface reaches the 
utmost width, so that the waves rolling over 
shallow water are broken, lose their energy and 
no longer reach the coastal cliffs. In such a case 
the latter crumble, and wide beaches or accumu- 
lative terraces are formed in their place. They 
are made up of material thrown up by the waves 
from the sea-bottom during the further destruc- 
tion and levelling up of the surface of the under- 
water abrasion terrace. 

The width of the underwater abrasion terraces 
in the stable regions of the coast varies widely, 
depending considerably on the stability of the 
rock, the abrasion and strength of the waves in 
certain regions of the coast. The underwater 
abrasion terraces in regions along the coast, 
made up of deposited strata of rock, are very 
wide. For instance, at the North-Eastern end of 
the Koryak upland, on the coasts of the Olyutor 
bay and Western Sakhalin the width of the under- 
water abrasion terraces frequently reaches 
1-1.5 km. Particularly wide underwater abrasion 
terraces can be found on the coasts made up of 
friable boulder bearing argillaceous grounds. 
Such terraces on the Eastern coast of the Bay of 
the Cross and North-Eastern Kamchatka are 
about 2-2.5 km wide. 

A lack of some indirect signs characteristic of 
the rising coast, namely: "drying lagoons", 
"uplifted benches", "accumulative forms with 
rock basis", form additional evidence for the 
stability of the above-mentioned coastal regions, 
taking also into account the data on the levellings. 

On the Far Eastern seacoasts, the whole com- 
plex of signs testifying to the definite direction 
of the present-day vertical displacement of the 
coast line is not often met with. On the contrary, 
symptoms may sometimes be found in one and 
the same region testifying to opposite signs of the 
present-day vertical movements. Such cases 
prove either the fluctuating character of the pre- 
sent-day vertical movements or a recent change 
of the sign into an opposite one. For example, 
the underwater coastal slope on the Western 
coast of Sakhalin has a profile in its lower part 
that is usually characteristic of subsiding coasts, 
while the levelling of the surfaces of accumulative 



forms and the presence of a bench near the shore- 
line (fig. 3 a) point to a rise of the land in this 
region. It appears that not long ago the vertical 
movement of one sign gave place to its opposite 
in this part. 

In connection with the late glacial transgression 
of the sea, an ingressive outlook is common to 
all the Far Eastern sea coasts. However, this can 
not be considered an indication of present-day 
subsidence of the coast, for on the rising coasts 
an eustatic rise of the level was not compensated 
by tectonic movements. Thus for those regions 
of the coast where we noted a rise, the latter is not 
relative but absolute as to its sign. 

A negligible subsidence or stability of individ- 
ual regions of the coast should be estimated as 
relative displacements, for they are the algebraic 
sum of an eustatic rise of the level of the World 
Ocean at the late glacial time and of the tectonic 
movements of the earth's crust. 

It is clear that the speed of movements of the 
coast regions going through the same displace- 
ments may be different. 

On the Far Eastern coasts in general, no region 
with considerable speeds of vertical movements 
can be found like those registered in Fennoscan- 
dia, Nova Zembla and the Caspian Sea. There- 
fore the differences in the speeds of movements 
of individual regions of the coast may only be 
estimated conventionally according to the dif- 
ference between the heights of old beach ridges 
and newer ones or vice versa. As an example, 
the difference in the height of the old beach ridges 
of accumulative forms in the open regions of the 
coast of Western Kamchatka in regard to the 
modern ridges amounts to 6-7 m and on the 
Chukotka Peninsula to 1.5-2 m. This fact shows 
that the extent and apparently, the speed of the 
relative subsidence of the Western coast of 
Kamchatka during the historical time exceeds 
3-4 times those of the Eastern part of Chukotka. 

Determination of the speed of vertical move- 
ments as well as their duration is impossible 
because we do not know the average interval of 
time during which definite types of accumulative 
forms and individual beach ridges are created. 
The uncertainty as to determining these values 
is still more aggravated by the fact that the ac- 
cumulative forms can be repeatedly abraded and 
reconstructed during the process of their develop- 
ment. At the same time, the difference in the 
relative uplift of the ridges can, in many cases, 
be determined by the peculiarities of the wave 
regime in the given region of the coast and by 

47 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



the character of the material of which the accu- 
mulative form is made up. 

Application of precise methods for determin- 
ing the age of the accumulative forms using 
C14 isotope may give an answer to the question 
about the speeds of the vertical movements of the 
coasts, also of the duration of these movements 
and of the moment of change of their signs. In 
the Southern regions the method of determining 
the age of the beach ridges of different generations 
by the annual rings of trees growing on these 
ridges (Galazy, 1955) could be applied for these 
purposes. More detailed archaeological explo- 
ration of primitive human settlements sometimes 
found on the accumulative forms, will undoubted- 
ly furnish a lot of interesting material compar- 
able to long periods of observation of various levels 
in different points of the Far Eastern seacoasts. 

More detailed exploration of the coasts of the 
Chukotka, Bering, Okhotsk and Japan Seas will 
undoubtedly show a more complex picture of 
differentiated present-day vertical movements of 
the coasts and the choice of the more indicative 
evidences will make it possible to establish con- 
nections between individual tectonic structures 
and the vertical displacement of certain sections 
of the earth's crust. 

REFERENCES 

Budanov V.I., 1951, Concerning the Method of 
Study of Seashores. Scientific Publica- 
tions of the Oceanology Institute, USSR 
Academy of Sciences, 5. 

, 1951, On Raising of Seashores of 

Maritime Territory. Scientific Publica- 
tions of the Oceanology Institute, USSR 
Academy of Sciences, 6. 

and lonin A.S., Present Vertical 

Movements of Western shores of the 
Bering Sea. Scientific Publications of 
the Oceanography Committee, Presi- 
dium of the USSR Academy of Sciences, 
1. 

Galazy G.I., 1955, Botanical Method of Deter- 
mination of Dates of High Historical 
Water-Levels and of Some Other Pheno- 
mena of the Lake Baikal. The Far 
Eastern Academy of the USSR, 103, 
(5). 



Johnson D.W., 1919, Shore processes and shore- 
line development. New York. 

lonin A.S., 1955, New Data on Vertical Move- 
ments of Seashores. Scientific Publica- 
tions of Oceanology Institute, USSR 
Academy of Sciences, 13. 

Kanayev V.P., 1958, New Geomorphological 
Observations on the Kuril Islands. 
Scientific Publications of the Oceanology 
Institute, USSR Academy of Sciences, 
32. 

Kaplin P. A., 1957, On some peculiarities of the 
North-Eastern shores of the USSR. 
Scientific Publications of the Oceanogra- 
phy Committee, Presidium of the USSR 
Academy of Sciences, 2. 

Knappen R.S., 1929, Geology and mineral re- 
sources of the Aniakchak District. 
U.S. Surv. Bull. 797. 

Lymarev V.I., 1955, Basic regularities of shore 
formation of some volcanic islands of 
the Kuril ridge. Scientific Publications 
of the Alma-Ata State Pedagogical Insti- 
tute named after Abai, natural geography 
series, 1. 

Moffit F.H., 1954, Geology of the Prince Wil- 
liam sound region, Alaska, Washington. 

Okayama T., 1931, Relation between topogra- 
phy and resylts of Precise Levelling. 
Journal of Geology, 8 : (4). 

Valentin H., 1952, Die Kiisten der Erde. Ergan- 
zungsheft zu Petermans Geogr. Mitt. 
246, Gotha. 

Zenkovitch V.P., 1948, Methods of determining 
vertical movements according to shore 
morphology. Scientific Publications of 
the Council on methods of studying move- 
ments and deformation of the earth-crust. 
Geodesy Publishing House. 

, 1949, Block bench as indication 

of sinking of shores. Scientific Publica- 
tions of the Oceanology Institute, USSR 
Academy of Sciences. 4. 

, 1950, On methods of lagoon formation. 

Reports of Acad. of Sci. of the USSR. 
75: (4). 

and Vladimirov A.T., 1950, Latest 

sinking of shores in Western Kamchatka. 
Reports of Acad. of Sci. of the USSR. 
72: (4). 



48 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



SUBMARINE MOUNTAINS IN THE KURILE RANGE AREA 

V. F. KANAYEV 

The Academy of Sciences of the USSR, USSR. 

(Abstract) 



1. In 1949-1956 the Institute -of Oceanology 
of the Academy of Sciences of the USSR carried 
out investigations of bottom relief in tne area of 
the Kurile Islands. Detailed studies have made it 
possible to discover some new important features 
of submarine relief and to mark some regularities 
of its structure. 

The Kurile range consisting of two ridges (the 
inner one-the Kurile Islands uplift and the outer 
a submarine ridge of the Viljaz) is a part of the 
present-day geosynclinal area. High tectonic 
activity and intensive surface and submarine vol- 
canism are responsible for the main features of 
composite bottom relief of the region. 

2. Before the investigations made by the 
Institute there was no authentic information about 
submarine mountains of the Kurile range. Now 
there are known 49 submarine mountains (among 
them no less than 26 submarine volcanoes), 41 of 
which are situated along the Okhotskoye Sea 
border of the inner ridge, five-along its axis and 
only three mountains are within the outer ridge. 
The majority of submarine mountains are located 
near the deepest gulfs, those of: Freeze, Bussol, 
Krusenshtcrn and Chetvcrty Kurilsky. 

3. Submarine volcanoes are, as a rule, conical. 
Their relative height varies from some hundred 



meters up to 2,500 m. The summits of the volca- 
noes are at depths from 60 to 2,260 m. The diame- 
ter at the base of the greatest volcanoes is up to 
20 km. The slope gradient is 17 which corre- 
sponds to the gradient of the middle part of the 
slopes of surface Kurile volcanoes. Some sub- 
marine volcanoes are active. 

4. Both submarine and surface volcanoes of 
the range are characteristically situated in linear 
direction both along and across the range. The 
transverse rows consisting of 3-5 volcanoes are 
located mainly near deep gulfs as well as the latter 
are connected with deep fractures. 

5. Some submarine volcanoes and mountains 
have flat tops covered with boulders, pebbles and 
sand. As a rule tops are at the depths of 100 to 
1 50 m, but in several cases at much greater depths 
up to 950 m. The formation of flat tops at the 
depths up to 150 m. may be attributed to abrasion 
which took place when the sea surface was lower 
during the quaternary glaciation. Volcanoes, 
the tops of which are at greater depths, have un- 
doubtedly suffered tectonic subsidence. 

6. The above mentioned distribution of sub- 
marine volcanoes and mountains can be seen on 
the geomorphological map of the Kurile Islands 
area, compiled in the Institute of Oceanology. 



49 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PACIFIC FLOODINGS OF THE CANADIAN ROCKY MOUNTAIN AREA 

P. S. WARREN and C. R. STELCK 

University of Alberta, Edmonton, Canada. 



INTRODUCTION 

The study of paleogeography in North 
America has been synonymous with the name of 
Charles Schuchert for half a century. Through 
insertions in text-books, his maps became the 
background for the study of ocean floodings onto 
the North American continent. Of necessity, 
speculation largely determined his paleogeograph- 
ic pattern for north-west Canada. The results 
of the past decade of oil exploration in western 
Canada permits a modification of Charles 
Schuchert's posthumous legacy (1955) concerning 
the distribution of lands and seas in North 
America. Seas with a Pacific connection extend- 
ing eastward into northwest Canada are the 
particular concern of this contribution. 

The earliest detritus deposited on the Pacific 
margin was derived (Warren 1951) from the 
igneous-metamorphic complex of the Canadian 
shield. This craton is flanked on the north and 
west by sedimentary belts. One belt, passing 
through the Canadian Arctic archipelago, strikes 
north-east; the other, including the British Colum- 
bia Cordillera, strikes north-west. It is customary 
to think of the Arctic archipelago sediments as 
"Boreal" and the British Columbia sediments as 
"Pacific". It is doubtful if such discrimination 
is valid until after mid-Lower Cretaceous time. 

PRECAMBRIAN 

In Beltian (late Precambrian) time the Pacific 
Ocean lapped over most of the Canadian Rockies 
area from the southern boundary of Canada into 
the Yukon Territory. The sediments were derived 
from the craton to the east (Warren 1951). There 
is no evidence that at this time there was any land 
mass (Cascadia) lying to the west. The western 
half of British Columbia was covered by deep 
water, too far from shore-line to receive signi- 
ficant clastic sediment. The Belt sediments appear 
only in eastern British Columbia and Central 
Yukon. The near-shore shallow-water facies 
may be traced by calcareous algae in the southern 
portion of the Rockies and by actual hiatus in 
the northern Rockies and eastern-most Yukon. 
In Canada, the Rocky Mountain trench probably 
marks the approximate western boundary of the 

50 



pre-Beltian craton. The positive and negative 
elements of the radial segmentation of the craton, 
indicated by Burwash (1957), created a sinuous 
shoreline of headlands and embayments. The 
most critical headland was in the latitude of 
Peace River; the most obvious embayment was 
in the area of the southern Canadian Rockies. 
The southern boundary of this embayment was 
"Montania". The Yukon positive area marks 
an arbitrary division between the "Boreal" sedi- 
mentary margin and the Pacific margin in the 
same way that Alaska at the present day separates 
the Arctic and Pacific oceans. 

PALAEOZOIC 

At the start of the Palaeozoic, the Pacific Sea 
transgressed the continental shelf and flooded, 
in part, the basement portion of the craton. 
The deepest penetration was made in the embay- 
ments which probably represented drainage basins 
of major Precambrian river systems. The Lipa- 
lian interval within the embayments was un- 
doubtedly of short duration. 

The Lower Cambrian quartzites probably re- 
present a continuation of Precambrian conditions 
as differentiation is made only on the presence or 
absence of trilobites. Calcareous algae in the 
Lower Cambrian indicate shoreline depths along 
the line of the west side of the Rockies, west of 
Fernie, in British Columbia. Banff and Jasper 
in Alberta, farther north, appear to be in the heart 
of the embayment from the Pacific with very thick 
Lower Cambrian sections. The increased flooding 
into the embayments in Middle Cambrian time 
brought the seas into the area east of the Rockies 
in southern Alberta. By Upper Cambrian time 
the seas extended as far east as Saskatchewan 
reducing the size of the Montana headland and 
flooding the Williston basin. North of the Peace 
River "high" the waters of the Pacific coalesced 
with those of the Arctic in Lower and Middle 
Cambrian time and salt-pans developed on the 
depressed northwestern margin of the craton. 

Graptolitic shaly deposits of Lower Ordovician 
to Middle Silurian age along the west side of the 
southern Rockies, in the western Mackenzie 
Mountains and in the Richardson Mountains, 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



are in marked contrast with the predominently 
limey shelf-facies of the eastern Rockies and the 
craton. The extensive flooding of the craton 
in Ordovician time probably left only the head- 
lands of Montana and the Peace River high as 
islands, marking the Western margin of the 
drowned continent. 

In Silurian time the intra-cratonic basins and 
Pacific embayments were re-defmed by conti- 
nental uplift and the headlands were once again 
connected with the inner craton. No rocks of 
Silurian age have been found between the Willis- 
ton basin and Great Slave Lake. (Rutherford 
1951). The Pacific embayment in the southern 
Rockies area was restricted to the edge of the 
craton whereas the Liard embayment was con- 
tinuous with the Arctic sea before the Caledonian 
disturbance. Uplift in Late Silurian and Early 
Devonian time expelled the seas from the craton 
leaving evidence of deposits of this age only in 
northern-most Yukon. Elsewhere, earlier Palae- 
ozoic deposits suffered erosion, and angular 
unconformities representing the Caledonian 
interval are present in northwest Canada. 

At the beginning of Middle Devonian time the 
northwest margin of the craton was depressed, 
and flooding extended from the Arctic to the 
Peace River protaxis. South of this, the sea did 
not reach east of the Rocky Mountain trench. 
The faunas attending this flooding were cosmo- 
politan in aspect and later Middle Devonian faunas 
contain many Chinese types. The Stringoce- 
phalus sea flooded through the Liard embayment 
from the Pacific, spreading behind the high land 
that marked the western margin of the hedreo- 
craton to inundate the low areas toward the 
Williston Basin. This landlocked arm developed 
salt basins fringed by reefs. There is no evidence 
that boreal connections were broken at this time 
but an eastern margin to the flooding is traced by 
Stringocephalus-bearmg reefs aligned with the 
the present margin of the shield as exposed today. 
Regression of this sea left an erosional hiatus, 
marked by plant remains, over most of western 
Canada. Re-expansion of the Pacific flooding 
through the Liard embayment took place in Upper 
Devonian time with progressive transgression 
until western Canada, including the headlands, 
was inundated. Late Caledonian (Acadian) 
disturbances raised the Arctic area, provided 
coarse, clastic plant-bearing beds and destroyed 
the epicratonic coalescence of Pacific and Arctic 
waters for the remainder of geologic time. The 
uplift in the boreal area was complemented by 
the depression of the entire western Canada 



Pacific margin, and the Montana and Peace River 
headlands were encompassed and flooded by the 
sea. The faunas of the late Devonian (Palliser) 
time show strong Asiatic affinities. 

After a minor withdrawal of the Pacific Ocean 
the Liard embayment acted as an exogeosynclinal 
downwarp and thick black shale was deposited 
with detritus from the Yukon high. The Pacific 
transgressed over the Peace River and Montana 
highs to flood Alberta and the Williston basin 
with shallow epi-continental seas. A late Missis- 
sippian sandstone facies developed along the 
northern margin of the Liard embayment. South 
of the Liard area the Pacific transgression depo- 
sited shallow-water shale and limestone with 
chert in the Rocky Mountain area. The chert 
reflects the incipient volcanism of the Fraser belt 
farther west. It was the development of the 
volcanic archipelago of the Fraser belt that first 
provided a source for sediments from west of the 
craton. Sympathetic uplift of the craton during 
world-wide Late Palaeozoic disturbances expelled 
the Pacific ocean by mid-Pennsylvanian time to 
a position west of the present Rockies. Accen- 
tuation of the volcanic island chains of western 
British Columbia created the "Cordilleran" 
geosynclinc west of the craton. Thick fusulinid- 
bearing Permian sediments, interbedded with 
volcanics, are found throughout western British 
Columbia but only thin shore-line clastic sedi- 
ments are found in the Rocky Mountain area. 
The clastic sediments extend farther to the east 
in the Liard and Peace River areas to lie uncon- 
formably on Mississippian rocks. The Cordil- 
leran geosyncline was restricted in the north by 
the promontory of the Yukon high, and Permian 
elastics found in Northern Yukon are not part of 
the geosynclinal fusulinid facies. 

MESOZO1C 

The beginning of the Mesozoic was marked by 
a general subsidence of both the Pacific margin 
of the craton and the volcanic archipelago. This 
subsidence provided an epi-continental shelf 
receiving Lower Triassic elastics. In southern 
Alberta, east of the mountains, pre-Jurassic 
erosion has removed the shoreline facies but in 
the Peace River-Liard basin farther north this 
facies is preserved in subsurface, the Rocky 
Mountains carrying only the off-shore facies in 
outcrop. Uplift, accompanying re-activation of 
vulcanism in western British Columbia, left 
shallow limey sediments and evaporites in the 
Peace River area, by Middle Triassic time. The 
Upper Triassic sea transgressed east of the 

51 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Rockies only in the Peace River-Liard basin. 
The base of the chains of volcanic islands in 
British Columbia provided a lip to a partially 
euxinic basin, and corals and volcanics in the 
Upper Triassic were confined to the western side 
of the lip. In late Triassic early Jurassic time the 
western plains area suffered severe erosion re- 
moving Triassic beds and much of the late Palae- 
oczoic sediment. This uplift marked the end of 
the calcareous phase (Millard) of deposition 
along the Pacific margin of the Alberta area 
which had pertained since Lower Cambrian time. 

At the beginning of Jurassic time the seas were 
in much the same position as in the late Triassic. 
The Pacific advance into the Rocky Mountain 
area was earliest in the Peace River Liard basin 
where Hettangian faunas are known. For the 
remainder of Lower Jurassic time the shore-line 
of the Pacific lay to the east of the present Rockies 
and Foothills. In Middle Jurassic time the sea 
reached eastward to the Williston basin where 
limey phases are found. Along the Canadian 
Rocky Mountain foothills a black shale phase 
was persistent. Farther west, in western British 
Columbia, the island chain provided volcanics 
and greywacke. 

Mid-Upper Jurassic (Kimmcridge) time (post- 
Swift) marked the draining of the Sundance sea 
of the Williston Basin and north central United 
States through a narrow passage-way to the 
north-east of the Montana high. At the same 
time the Yukon high was accentuated. Between 
these highs, in the Canadian Rockies and foot- 
hills, marine arenaceous elastics mark the shallow 
neritic margin to the Pacific flooding. The two 
main river systems, one draining the old Sundance 
basin (Morrison) and the other draining north- 
eastern British Columbia, debouched into the 
Pacific. Estuarian facies developed in both 
northeastern and southeastern British Columbia 
bringing marine ammonites of both Portlandian 
and Tithonian ages as far east as the Rockies. 
There appears to be no important break to in- 
dicate the Jurassic-Cretaceous boundary. Coal 
swamps developed in south-eastern British 
Columbia. At the beginning of Cretaceous time 
the Selkirk mountains commenced to rise. This 
restricted the sea in south-eastern British Colum- 
bia. Farther north along the Rockies Aucella- 
bearing Neocomian sandstone marks, at this 
time, the greatest penetration of the Pacific on to 
the continent. The presence of ammonites and 
pelecypods of Lower Neocomian age in the foot- 
hills of the Peace River area, similar to those 
found in British Columbia on both sides of the 

52 



Coast Range batholith today, is sufficient evidence 
that the latter had not as yet appeared as an 
effective barrier. Further uplift of the Yukon 
high and northern British Columbia combined 
with further uplift in southern British Columbia 
left but an estuarian remnant of the old Pacific 
embayment. This estuary marked the main 
drainage exit for most of western Canada. 
Reflooding of the lower reaches of this river 
system in late Neocomian time marked the last 
transgression of the Pacific into the Rocky Moun- 
tain area. The regressive phase of the Pacific was 
marked by the development of coal swamps in 
the Rockies and Central British Columbia. The 
emplacement of the Coast Range batholith 105 
million years ago, (Folinsbee, et al., 1957) as 
well as the Nelson and Cassiar-Omineca batho- 
liths effectively prohibited further Pacific marine 
floodings (other than marginal) into the Cordil- 
leran region. From Aptian time onward the 
marine sediments of the Rocky Mountains and 
central plains areas were deposited in waters 
connected with the Arctic, Atlantic or Gulf of 
Mexico seas and not with the Pacific. 

REFERENCES 

Armstrong, J.E., 1949, Fort St. James 
Map Area, Cassiar and Coast districts, 
British Columbia. Geol. Surv. Can., 
Mem. 252. 

Baillie, A.D., 1953, Devonian system of the 
Williston basin. Mines Branch, Prov. 
of Manitoba, Pub. 52 (5). 

Bostock, H.S., 1948, Physiography of the Cana- 
dian Cordillera, with special reference 
to the area north of the fifty-fifth parallel 
Geol. Surv. Can., Mem. 247. 

Burwash, R.A., 1957, Reconnaissance of sub- 
surface Precambrian of Alberta. Bull. 
Amer. Assoc. Petrol. Geol., 41 (1): 
70-103. 

Crickmay, C.H., 1931, Jurassic history of North 
America; its bearing on the development 
of continental structure. Proc. Amer. 
Phil. Sor.,70(l): 1-102. 

Daly, R.A., 1950, Communication: Amer. Jour. 
Sci., 248:741-43. 

Folinsbee, R.E., Ritchie, W.D. and Stansberry, 
G.F., 1957, The Crowsnest Volcanics 
and Cretaceous Geochronology. Al- 
bert a Soc. Petrol. Geol. Guide Book, 
(in press). 

Frebold, H., 1953, Correlation of the Jurassic of 
Canada. Bull. Geol. Soc. Amer., 64 (10): 
1229-1246. 



VOLUMh 12 



GEOLOGY AND GEOPHYSICS 



Hume, G.S., 1953, Lower Mackenzie River 
area, Northwest Territories and Yukon. 
Geol. Surv. Can., Mem. 273. 

Kay, Marshall, 1951, North American geosyn- 
clines. Geol. Soc. Amer., Mem. 48. 

McLearn, F.H., 1953, Correlation of the Tri- 
assic formations of Canada. Bull. 
Geol. Soc. Amer., 64 (10): 1205-1228. 

Peterson, James A., 1957, Marine Jurassic of 
Northern Rocky Mountains and Wil- 
liston basin. Bull. Amcr. Assoc. Petrol 
Geol., 41 (3): 399-440. 

Rutherford, R.L., 1951, Structural interpreta- 
tion of loci of petroliferous parts of 
Devonian reefs in Edmonton area, 
Alberta, Canada. Bull. Amer. Assoc. 
Petrol. Geol., 35 (4): 844-853. 

Schuchert, Charles, 1955, (Posthumous edited 
by Dunber C.O.). Atlas of Paleogeo- 
graphic maps of North America. John 
Wiley & Sons, New York. 

Walcott, CD., 1928, Pre-Devonian Palaeozoic 



formations of the cordilleran provinces 
of Canada. Smithsonian Misc. Coll., 
75: (5). 

Warren, P.S., 1951, Rocky Mountain Geosyn- 
cline in Canada. Trans. Ror. Soc. Can., 
45 (4): 1-10. 

Warren, P.S. and Stelck, C.R., 1954, Stratigraphic 
significance of the Devonian coral reefs 
of Western Canada. Bull. Amer. Assoc. 
Petrol. Geol. Symposium, Western 
Canada Sedimentary basin, Tulsa, Okla- 
homa, pp. 214-218. 

Warren, P.S. and Stelck, C.R., 1956, Significance 
of the Cretaceous fossil succession of 
Western Canada. XX International 
Geological Congress, Mexico City, (in 
press). 

Webb, JB., 1954, Geological history of Plains 
of Western Canada. Amer. Assoc. 
Petrol. Geol. Symposium, Western 
Canada Sedimentary basin, Tulsa, Okla- 
homa, pp. 3-28. 



PLATE J 
Map 1. 
Map 2. 

PLATE II 

Map 3. 

Map 4. 

PLATE III 
Map 5. 

Map 6. 

PLATE IV 

Map 7. 

Map 8. 



EXPLANATION OF PLATES 

Paleogeographic map showing extent of Late Beltian and Late Lower Cambrian seas. 
Paleogeographic map showing extent of Early Upper Cambrian and Late Upper 
Ordovician (Richmond) seas. 

Paleogeographic map showing extent of Early Middle Silurian (Clinton) and Late Middle 
Devonian (Stringocephalus zone) seas. 

Paleogeographic map showing extent of Mid-Upper Devonian (D2) (T. cyniniformis 
zone) and Lower Mississippian (Middle Kinder-hook) seas. 

Paleogeographic map showing extent of Early Middle Permian and Lower Triassic 
(Flemingites zone) seas. 

Paleogeographic map showing extent of Middle Triassic (Late Ladinic) and Early Lower 
Jurassic (Hettangian) seas. 

Paleogeographic map showing extent of Early Upper Jurassic (Oxfordian) and Earliest 
Lower Cretaceous (Infra valanginian) seas. 

Paleogeographic map showing extent of Early Lower Cretaceous (Valanginian) and 
Mid-Lower Cretaceous (Upper Neocomian). 



53 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



C o m b r i o n 
Ordovician 




54 



Map 2. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Map 4. 



55 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



WESTERN 
. CANADA 

FTv^ M- Per mion 



EZZ L-Trlo.c 



WESTERN 
CANADA 



ZZ2M Triassic 



L- Jurassic 




56 



Map 6. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



nfrovolongioian* 



Volonginlon v Greta 
U- Neocomian 




Map 8. 



57 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PACIFIC TYPE OF STRUCTURE OF THE EARTH'S CRUST AND 
PROBLEMS PERTAINING TO THE ORIGIN AND GROWTH OF 

CONTINENTAL MASSES! 

P. N. KROPOTKIN 

Senior Scientific Researcher of the Geological Institute, USSR Academy of Sciences, USSR. 

E. N. LUSTIKH 
Senior Scientific Researcher of the Institute of Earth Physics, USSR Academy of Sciences, USSR. 

(Abstract) 



1. The report outlines the main principles of 
researches on the structure and development of 
the Earth's crust, published by the authors during 
the period of 1948-1957. The scheme suggested 
has quite a lot in common with the hypotheses of 
V.A. Magnitzky (USSR, 1953) and J.T. Wilson 
(Canada, 1948-1957). 

2. The gravimetric map of the World (1 : 22,000, 
000) and gravimetric maps of Eurasia, Africa and 
North America (1:6,000,000), compiled by the 
authors in Bouguer reduction according to ma- 
terials available in world literature, display clearly 
the difference between the Pacific and continental 
types of structure of the crust. Gravity anomalies 
in this reduction reflect with a precision up to 
50-100 milligals the depth of the Mohorovicic 
discontinuity, separating the crust (sial) from the 
heavy ultrabasic substratum (sima). This corre- 
lation has been established by a comparison of 
gravity anomalies with the data on the thickness 
of the crust in Middle Asia and in other points 
obtained by the seismic refraction method and 
other methods. 

3. Considering geophysical data the systematics 
of large structural units of the crust can be pre- 
sented as follows: 

A. Oceanic platforms platform regions, 
which occupy 40 per cent of the surface of the 
globe in those parts of the Pacific, Atlantic, Indian 
and Northern Arctic oceans where the depth of 
the sea exceeds 4000 m. They are characterized 
by a small thickness of the crust (4-13 km.), high 
positive gravity anomalies in Bouguer reduction 
(from + 200 to + 450 mgl.) and are, probably, 
closest to that original uniform structure of the 
external parts of the solid mantle, which preceded 
the formation of continental masses. 

B. Modern geosyncline regions subdivided in 
their turn into : a) regions of Cainozoic (Alpine) 



folding and volcanism in the Pacific and Alpine- 
Himalayan belts, consisting of geoanticlines and 
geosynclinal and internal troughs. Geoanticlines 
are usually characterized by gravity minima and 
a greater thickness of the crust (up to 75 km. in 
Hindu Kush range and on Pamir, where gravity 
anomalies come to -400 up to -500 mgl.); b) me- 
dian masses with a continental structure of the 
crust (sections of Paleozoic and Pre-Cambrian 
folding-Iranian, Hungarian and other masses); 
c) foredeeps, originating mainly on Pre-Cambrian 
and Paleozoic platforms Subalpino, Subcarpa- 
thian, Subhimalayan, etc. ; they are characterized 
mostly by negative (up to -50 mgl.) anomalies in 
Bouguer reduction and a considerable thickness 
of the crust ; d) foredeeps formed on the margins 
of oceanic platforms abyssal hollows of Kurile- 
Kamchatka, the Philippines, Puerto-Rico, etc. 
Many of these troughs are characterized by posi- 
tive anomalies in Bouguer reduction which indi- 
cate a small thickness of the crust, however, they 
have big negative anomalies in isostatic reduction 
and are highly seismic; e) median masses of deep 
internal basins, possessing a crust structure similar 
to the structure of the ocean floor, but with a 
greater thickness of the sedimentary veneer; their 
" anomalies in Bouguer reduction come to + 150 
mgl. to + 400 mgl. These are masses of deep 
depressions of the Mexican gulf, Caribean sea, 
Mediterranean sea, Banda sea in Indonesia, sea of 
Okhotsk, sea of Japan and the Bering sea. Paleo- 
geography provides proofs of a lengthy associa- 
tion of the sea basins to these depressions, which 
have been centres of sea transgressions, invading 
from time to time the adjoining land. 

C. Platform regions. They are characterized 
by a continental structure of the crust and Bouguer 
anomalies from + 50 mgl. up to + 500 mgl. With- 
in the present platforms it is possible to distinguish 
regions of Mesozoic (Pacific), Upper Paleozoic 



t Presented by Dr. E.V. Karus, U.S.S.R. 
58 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



(Hercynian), Lower Paleozoic (Caledonian) and 
Pre-Cambrian (subdivided into several cycles) 
folding. All these platform regions correspond to 
former geosyncline belts which originated as early 
as Pre-Cambrian and which experienced a closure 
during different geological periods. Pre-Cambrian 
platforms (shields, plates) are cores of continental 
masses of the sial, which were growing at the ex- 
pense of later zonal annexations owing to folding 
and injection of a great number of granitic 
intrusions. 

4. The material of the crust (igneous rocks as 
well as sedimentary, formed by their destruction) 
is being built up gradually during the entire geo- 
logical history of the development of the Earth, 
owing to the ascent of magma from the depths of 
the solid peridotite mantle. Magmatic acid 
(granitic, close to the eutectic quartz-alkaline 
feldspar, etc.), alkaline (close to the eutectic 
nepheline-feldspar, etc.), medium (of andesitic 
composition) and basic (basaltic, close to the 
eutectic plagioclase-pyroxene) melts have a tem- 
perature of melting much lower than peridotite 
and are segregated in the ultrabasic substratum 
by smelting of eutectoid mixtures. The source of 
energy leading to the local smelting of eutectics 
lies in radioactive heat and the energy of mechan- 
ical processes displayed in earthquakes at a depth 



of 60-800 km. The ascent of magma to the surface 
of the Earth proceeds along deep fractures both 
under the influence of tectonic stresses and owing 
to a lesser density of these melts as compared to 
the density of the simatic shell. 

5. Several stages can be traced in the develop- 
ment of geosynclinal regions. The earliest stage 
corresponds to the origin of fractures on the oceanic 
platforms (for instance the Murray fracture in 
the Eastern part of the Pacific ocean) and the 
formation of nearly straight submarine mountain 
ranges and island chains owing to the accumu- 
lation of volcanic material arriving from a great 
depth. Such are the Hawaii islands, the zone of 
Kermadec and Tonga islands on the continuation 
of New Zealand structure, etc. The next stage of 
development is illustrated by island arcs and archi- 
pelagoes like Indonesia. In the intervals between 
wide belts of the sial, formed along geoanticlines, 
there still have been at this stage less reworked 
relics of the original crust median masses of 
deep internal basins of "B" type. The further 
process of rework in the structure of the crust, its 
crumpling, disintegration and injection of magma 
brings about a closure of geosyncline systems and 
the formation of a mature continental platform 
or shields. 



59 



PROCEEDINGS OF THE NINTH PACII 1C SCIENCE CONGRESS 



CONTINENTAL DRIFT AND THE PRESENT VELOCITY OF SHIFT OF 
THE CONTINENTAL MARGIN OF EASTERN ASIAt 

TING YING H. MA 

National Taiwan University, Taipei, Taiwan. 

(Abstract) 



From coral data it can be traced that an ancient 
continental mass of Laurasiafrica was separated 
into the present major continents which have 
reached their present relative positions through 
widening of the Arctic, Atlantic and Indian 
Oceans. Meanwhile the continent of Australia 
shifted toward Southeast Asia with counter-clock- 
wise rotation. The motion of the Americas to- 
ward the Pacific caused the orogenic belts of the 
marginal tectonic complex on their west coast. 
The motion of two Americas against each other 
caused the orogenic belts of the West Indies inter- 
continental tectonic complex. The clockwise 
rotation of Africa from India against Europe 
caused the orogenic belts of the Mediterranean 
intercontinental tectonic complex. The motion 
of Asia into the Pacific resulted in (1) the orogenic 
belts of the East Indies intercontinental tectonic 
complex against the northwestward motion of 



Australia, (2) the orogenic belts of the Himalaya- 
Assam intercontinental tectonic complex against 
the held stable Deccan Massif and (3) the orogenic 
belts of the marginal tectonic complexes repre- 
sented by the island chains and geanticlinal ridges 
in the Western Pacific. The shear planes repre- 
sented by present earthquake foci on the margin 
of a continent or between two crustal masses are 
the yet weak zones over which crustal masses were 
overthrusted during the last sudden total displace- 
ment of the solid earth shell that shook up the 
the crustal masses. There is a slow motion of 
crustal masses over these shear planes due to the 
rotation of the earth and the amount of lateral 
shift can be determined from the amount of uplift 
because the angle of the shear plane is permanent. 
From the gradual rise of the continental margin of 
Eastern Asia it can be calculated that there is a 30 
cm. shift toward the Pacific per century at present. 



t Published in the First Series of private research publications by Ting Ymg H. Ma, Research on the Past Climate and 
Continental Drijt, 12 : October, 1957. 



60 



VOLUME 12 GEOLOGY ANDGEOPHYSICS 

GEOTECTONICS OF THE PACIFIC: DIVISION OF THE NORTHERN 

PACIFIC INTO TWO OCEANIC PARTS, AND THE TECTONIC 
COMPARISON OF BOTH THE CONTINENTS, WESTERN AND EASTERN 

SH1NGO EHARA 

Geographical Institute, Ritsutneikan Universitv, Kyoto, Japan. 



INTRODUCTION 

The Northern Pacific may be divided into two 
oceanic parts, a western and an eastern, by tecto- 
nic lines, represented by the Emperor Sea Mounts 
and the Hawaiian Chain. The former runs ap- 
proximately NNW. along the Emperor Sea 
Mounts while the latter trends WNW.-ESE. 
carrying large volcanoes at its eastern end. They 
join together west of Midway Island. 

The most remarkable tectonic differences 
between the western and eastern continents 
are: In California, where shallow earthquakes 
predominate, both, trenches as well as deep- 
earthquake zones are missing. In eastern Asia, 
however, there arc the Nippon and Mariana 
trenches associated with deep-earthquake zones; 
and furthermore the Ryukiu and Philippine 
trenches accompanying deep-earthquake zones 
which occupy the inner side of the former. The 
tectonic difference between the two continents 
may be mostly due to the strength of the orogemc 
force from the southern Pacific which may be 
verified by the tectonic structure of the Pacific. 

In the Japanese Is. we have experienced that 
the geotectonics of the Is. was subjected to lateral 
thrusts coming as well from the Pacific as from 
the Continent. Going further south along the 
Nippon and the Mariana trenches we reach the 
Caroline Sea, where is found not only the 
direction of the Pacific movement which has 
brought about the Yap-Palau echelon and the 
Halmahera orogene, but in the Polynesian chain 
we also encounter Dana's axis of the Pacific, 
manifesting the tectonic trend of the western 
Pacific. 

WESTERN PACIFIC 

THE JAPANESE TRANSVERSE RIFT AND THE SHICHI- 
TO DEEP-EARTHQUAKE ZONE 

In Eastern Asia there are two parallel zones of 
deep-earthquakes associated with the trenches 
lying on the inner and the outer side. The outer 
zone lies along the boundary between the sima 
crust exposed on the Pacific floor and the border 



land of the Asiatic continent, represented by the 
Nippon, Mariana and Chishima trenches. The 
inner zone lies between the borderland and the 
Asiatic continent represented by the Philippine 
and the Ryukiu trenches. Probably these two 
zones might have been formed at the same time 
but their relation has not been confirmed yet in 
detail, therefore one of the outer trenches may 
here be discussed in detail. 

Shfchfto deep-earthquake zone: The Shichito 
trench, running north-south, delineates an arc 
with the convex side toward the west, between 
Ogasawara Is. and Cape Inubo. It comes into 
contact with the Shichito batholith underlying 
the Shichito submarine ridge. The fact suggests 
that the Shichito trench, whose depth reaches 
over 9,000 m, was subjected to the erogenic force 
coming from the Pacific floor, which presses upon 
the Shichito batholith. 

The Shichito batholith which is subjected to 
this erogenic force over a distance of 500 km., 
between Oshima I. and the Sofia rock, might have 
produced the shearing plane running NNW.-SSE. 
through which the Fuji volcanic zone erupts. 
At that time, on the one hand, the tapering apex 
of the Shichito batholith pushed into the outer 
zone of central Honshu and bended the Median 
line forming the Toyohashi-Suwa arc; on the 
other-hand, the transverse rift (Itoigawa-Nirazaki- 
Sunto line) was made between the Kwanto range 
and the Mino-Hida plateau, along which the 
Kwanto range was horizontally moved over about 
60 km. northward by the orogenic force of the 
Pacific and formed on the latter the echelon of the 
Nippon Alpine range Hida, Kiso, and Akaishi. 

The transverse rift trends parallel to the 
Shichito deep-earthquake zone extending north- 
north-west and by transversing the Japan Sea may 
reach the continent. 

The closest connection may be suspected be- 
tween the transverse rift and the Shichito deep- 
earthquake zone. The transverse rift may form 
a fault plane dipping west, extending into the 
earth interior; first after advancing some dis- 
tances to the west it may diverge to a fault plane 
at a depth of 250 km. which corresponds to one 

61 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



of the intermediate earthquake zones, then it may 
descend steeply toward the west and reach a depth 
of over 400 km. in the deep-earthquake zone. 

The transverse rift and the deep-earthquake 
zone suggest, that in the beginning of the Miocene 
the Pacific orogenesis was powerful and profound ; 
on the one hand it built up an echelon of Nippon 
Alpine ranges at the surface of the earth, on the 
otherhand, the fault plane which declines away 
from the Pacific and reaches till 400 km. and more 
in the depth where deep-earthquakes originated. 

EASTERN PACIFIC 

From Alaska via British Columbia to Cali- 
fornia there are no marked oceanic deeps or 
troughs. The present structure of California is 
largely determined by block faulting, although 
older folded structures exist, and folding appears 
to be still in progress in the Coast Range. In the 
Coast Range the most conspicuous and most 
active faults are strike slip features associated 
with a characteristic rift topography. The main 
fault of these is the San Andreas Fault, with several 
branches and parallel structures. 

SAN ANDREAS RIFT 

The San Andreas Rift whose trend is northwest 
to southeast, starts from the Cape of Pt. Arena 
running southeast through the San Francisco 
Peninsula, and passing through the neighbourhood 
of Stanford extends further south and reaches 
Salton Lake. The entire length is appr. 500 miles, 
including an extension into the sea, which is out 
of sight, and the depth of the fault plane may be 
said to reach 100 km. 

With regard to the origin of the rift, B. Willis 
gives the following explanation: "Since the strike 
of the San Andreas is about northwest-southeast, 
the effective stress should impinge upon the fault 
plane from south or north approximately." In 
this determination he may be a little too careful, 
but the effective stress must have come from the 
Pacific floor which lies to the south of the rift. Ac- 
cording to Gutenberg and Richter, the San An- 
dreas is accompanied by a zone of shallow 
earthquakes but not of deep or intermediate ones. 

The San Andreas whose depth does not exceed 
100 km., is unable to accompany a deep or inter- 
mediate earthquake zone and trench; however, 
in Eastern Asia, the transverse rift which depth 
reaches approximately to 500 km., might have 
caused the formation of the deep or intermediate 
earthquake zone and trench. The shallower 
depth may be due to the weakness of the stress 

62 



coming from the Pacific, but the deeper to the 
strong one coming from the Pacific floor. 

SUBMERGENCE OF THE SOUTHERN 
CONTINENT 

According to Gutenberg and Richter, in the 
southern Pacific shallow earthquakes predomi- 
nate around the Easter Is., which on the one hand 
extends toward the west occupying the south of 
the Polynesian chain, while on the other side it 
approaches the east of New Zealand. If the zone 
of shallow earthquakes is the scope of the old 
continent it might have occupied 1 /3 of the south- 
ern Pacific. In the submergence, compression 
might have been caused around the southern 
Pacific, especially in the 3 directions, east, west 
and north-west; to the east the Andes are pushed 
toward the Brazilian shield, and the trenches at 
the foot of the Andes might have increased the 
depth in great magnitude, probably extending 
the fault plane dipping east into the earth interior 
which is associated with the deep and intermedi- 
ate-earthquake zones; to the west, however, the 
borderland of Australasia is pushed toward 
Australia; wherein the compression of New Cale- 
donia, New Hebrides, Solomon and Fiji Is. 
Pressure from the Pacific, as Andrews once men- 
tioned, might have arisen; and the trenches of 
Tonga-Kermadec might have increased the depth 
in great magnitude, probably extending the fault 
plane dipping west into the interior of the earth, 
which is associated with as well the deep as the 
intermediate earthquake zones. 

In the north-west the si ma crust, exposed on 
the Pacific floor, is subjected to compression, and 
produced many fissure eruptions which are repre- 
sented by the Polynesian and the Caroline chains. 
Beyond the tropics, the compression extended 
itself to the north-west Pacific toward Japan and 
Chishima, where orogenesis, the deepening of 
trenches accompanied by deep-earthquake zones, 
is strikingly developed. 

REFERENCES 

Andrews, E.C., 1921, The Framework of the 
Pacific. Proc. First Pan-Pacific Sc. Cong. 
Hawaii, 3: 875-881. 

Benson, W.N., 1924, The Structural Features of 
the Margin of Australasia. Trans. New 
Zealand Inst. 55:99-137. 

Dana, J.D., 1845, Manual of Geology, p. 37. 

Daly, R.A., 1916, Problems of the Pacific Islands. 
Amer. Jour. Sc. (4th series) 41. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Dietz, R.S., 1954, Marine geology of North- 
western Pacific: Description of Japanese 
Bathymetric chart 6901. Bull. Geol. Soc. 
Amer. 65: (12) Part 1, 1199-1224. 

, and Menard, H.W., 1953, Hawaiian 

Swell, deep and arch, and Subsidence of 
the Hawaiian Islands. Jour. Geol. 61: 
99-113. 

Ehara, S., 1953-54, Geotectonic.s of the Pacific 
concerning the Japanese Is., I-1V. Jap. 
Jour. Geol. Soc., 59-60. 

, 1955-56, Geotectonics of the Pacific 

with reference to South- Western Japan. 
I-IIJ. Ibid. 61-62. 

, 1957, Geotectonics of Northwestern 
Honshu, Hokkaido & Chishima Islands. 
Ibid. 63, No. 737. 



Ehara, S., 1957, Geotectonics of the Yap-Palau 
echelon brought about by the Pacific 
movement. Ibid. 63. 

Gutenberg, B. & Richter, C.F., 1949, Seismicity 
of the Earth. Princeton Univ. Press. 

Marshall, P., 1923, General statement on the 
structure of the Pacific Region. Proc. 
Pan-Pacific Sc. Cong. Australia, p. 730. 

Suess, E., 1909, The Face of the Earth. 4. 

Willis, B., 1926, Geotectonics of the Pacific. 
Proc. Third Pan-Pacific Sc. Cong. Tokio, 
1 : 258-369. 

and Willis, R., 1929, Geologic structures. 

Second Edition, McGraw-Hill Book 
Company. 



63 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCL CONGRESS 



PACIFIC INFLUENCES IN THE TECTONICS OF EASTERN AUSTRALIA 

E. SHERBON HILLS 

Department of Geology, University oj Melbourne, Victoria, Australia. 

(Abstract) 



The word "Pacific" is used herein for geological 
attributes related to the present major features of 
the Pacific Ocean and its margin. 

In Upper Protcrozoic time tillitcs and ru- 
daceous-arenaceous sediments were widespread. 
The tillites were in part deposited in geosynclinal 
troughs and the implication of both facies is that 
at that time parts of Australia were cratonic, 
while other belts were geosynclinal. 

This distinction is reflected in the present con- 
tinental structure, which therefore bears a certain 
resemblance to that of the Upper Proterozoic. 
In Lower Cambrian times submarine basic lavas 
and tuffs in Victoria represent a volcanic pile in 
a geosyncline flanked by land on the south (Tas- 
manian craton), on the north-east, and probably 
on the north-west beneath the Murray Basin. 
These are typical of the thick ophiolitic facies, 
such as is seen in northern Syria (described by 
Dubertret). The existence of flanking pre-Cam- 
brian blocks is seen in the wide distribution in 
Victoria of arenaceous-argillaceous beds con- 
taining much detrital tourmaline, felspar and 
quartz, derived from the north-east, also the 
Upper Ordovician is neritic in New South Wales. 

The existence of Cambrian trilobitic limestones 
in Victoria and in the South Island of New Zea- 
land demonstrates neritic facies and shows a 
structural high where New Zealand now exists, 
with sea between (Lower Ordovician graptolites 
are similar in Victoria and New Zealand). The 



broad pattern already bears a resemblance to the 
present. 

Vulcanicity and igneous intrusions in Eastern 
Australia from Cambrian to Ccnozoic show 
widely ranging magma types, but the distribution 
is always within the mobile eastern zone, suggest- 
ing a constant tectonic relationship with the main 
Pacific margin. It is suggested that the Devonian 
lamproph\ricand the hypcrsthenr dacitic magmas 
of Victoria were injected as a magmatic wedge 
from the direction of the Pacific. 

Cenozoic volcanic trends and belts are clearly 
related with parallel features in the Tasman Sea, 
the Coral Sea and the Pacific margin. 

The former cxtcn^on of Australia towards the 
East is unquestioned. The present boundaries 
and the elevation of the Eastern Highlands tecton- 
ic, not due to isostatic uplift, so that the geolog- 
ical resemblances are a reflection over common 
tectonic origin geometrically related to the Pacific. 
The geological evidence indicates a thick stable 
shield lying to the west; a broad zone of thinner 
basement rock beneath the Great Artesian and 
Murray Basins; a complex geosynclinal zone on 
the east ; and a subsided, probably thin sialic area 
beneath the Coral and Tasman Seas. 

Thus the overall picture is in accord with the 
major tectonic elements of the Australasian 
region, and, with variations, this has been so since 
the Upper Proterozoic. 



64 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



THE ROLE OF LATERAL FAULTING IN CIRCUM-PACIFIC 
OROGENY IS THE PACIFIC BASIN ROTATING? 

PIERRE ST. -AM AND 

Michelson Laboratory, U.S. Naval Ordnance Test Station, China Lake, California, U.S.A. 

(Abstract) 



The geologic structure of the eastern shore of 
the Pacific Ocean from Baja, California, to a point 
off the Washington-Oregon coast is dominated 
by the San Andreas Fault and sub-parallel strike 
slip faults, right lateral in nature. The faulting 
in southeastern Alaska is also right lateral. The 
Denali fault in the Alaska Range appears to be 
right lateral as does the Nixon Fork-Iditarod 
fault. Right lateral faulting has been described 
from the Alaska Peninsula. Seismic evidence shows 
that much of the Aleutian Island faulting is right 
lateral. First motion studies by Hodgson show 
the Kamchatka- Kurile Arc to be largely right 
lateral in displacement. Benioffhas demonstrated 
on the basis of distribution of aftershocks that 
the major faulting there is right lateral in sense 
and parallel to the Arc. 

Gorshkov describes a tectonic pattern in this 
area that indicates that it is being deformed in 
shear by a dextral couple parallel to the arc. 

Faulting in Japan is thought to contain a right 
lateral component parallel to the arc. The Alpine 
fault in New Zealand is right lateral and of a com- 
patible direction. 

It is therefore concluded that the Pacific Basin 
is rotating counter-clockwise with respect to the 
continents. 

The cause of the movement is suggested as being 
a Coriolis force resulting from a convergent con- 
vection cell under the Pacific. 



The present zone of orogeny extends inland in 
the United States and Alaska for 100 miles or 
more. 

Old lines of faulting such as the Rocky Moun- 
tain Trench suggest that the orogenic zone was 
larger or extended further to the east than it now 
does. It is thought that this motion is very old 
and has been going on since before the end of 
Mesozoic time. The orogeny in a given place 
decreases as the continental crust forms and 
stiffens or as the orogenic cell decreases in size 
or drifts from place to place. It appears that the 
continents are growing at the expense of the 
Pacific Ocean basin. 

The peripheral velocity of the rotation is in 
excess of 20 feet per century on the eastern side 
of the Pacific. 

The primary structural geologic forms are 
lateral faults, with conjugate shears producing 
normal "tensional" faults or reverse faults, thrust 
faults and folds as compressional features. Vol- 
canoes develop in the areas between "en-echelon" 
lateral faults or at the intersection of these with 
the tensional conjugate shears. 

The structural picture is complicated by the 
intersection of submarine topographical aligne- 
ments such as the Mendocine and Murray escarp- 
ments with the peripheral orogenic zone. The 
regions of intersection being the transverse ranges. 



65 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



SEISMIC RESULTS IN RELATION TO THE ANDESITE LINE 

T. F. GASKELL 

Exploration Department, British Petroleum Company, Ltd., London, England. 



During the past ten years a considerable num- 
ber of seismic measurements have been made in 
the Pacific Ocean. This work is continuing, and 
although much more measurement is needed to 
determine the geological structure in all parts of 
the ocean, it is possible to make some general- 
isation which fit with the results already published. 
These generalisations are of use in indicating 
where future work will be of most interest. 

The seismic refraction method has produced 
the greater part of the information that exists 
about deep ocean sea-bed structure; reflections 
have assisted sometimes in interpreting the re- 
fraction results, but alone they are a weak tool 
because no bore -holes or outcrops are available 
to allow a determination of the vertical velocity 
profile. One of the important numbers that the 
refraction method provides is the velocity of 
compressional waves in the various rock layers, 
and much of generalisation that is possible with 
the sea seismic results depends on correlating 
similar velocities found at different places. It is 
unfortunate that each rock type does not possess 
a unique value for its compressional wave velo- 
city. Limestones for example extend from about 
2 Km/sec to 6 Km/sec, a range of values which 
overlaps severely those for volcanic rocks, for 
which 4.5 Km/sec has been found for Hawaiian 
lava flows, and values ranging up to over 8 Km/ 
sec for basic rocks such as dunite. Since the 
seismic method can only measure travel times 
and velocities it can never postulate for certain 
what is the geological structure. What it does do 
is show the most probable structure and also 
restrict the field of geological speculation. 

There appears to be a comparatively simple 
geological structure in the sea-bed beneath the 
deep Pacific ocean. This structure is represented 
by a layer within 1 or 2 Km of the sea-bed, in 
which the compressional wave velocity is 6.7 
Km/sec (Raitt 1956, Gaskell and Swallow 1952, 
Eiby 1957, Officer 1955). The overlying material 
is partly low-velocity sediment which is from 
0.1 to 1.5 Km thick, with a mean (obtained with- 
out regard to the distribution of observations, so 
that it tends to be weighted to the areas where 
there are most measurements) of 0.3 Km. There 

66 



is evidence that a Layer 2 exists between this 
soft sediment and the 6.7 Km/Sec layer. The 
Layer 2 has been recorded with velocities ranging 
from 4.5-6.3 Km/Sec and its normal thickness 
averages about 1 Km. The seismic results do 
not indicate whether the Layer 2 extends down 
to the 6.7 Km/Sec layer, or whether it is a band 
of hard rock separating an upper and a lower 
layer of soft sediment. In some parts of the 
ocean basin refracted waves from a second layer 
are not observed because they are masked by the 
waves from the 6.7 Km/Sec layer, but evidence of 
a second layer is provided by a study of shear 
waves and of reflections (Gaskell and Swallow 
1954). 

When measurements are made near volcanic 
islands the 6.7 Km/Sec layer is deeper than normal 
and clear indications of Layer 2 are provided by 
first arrival refracted waves. For example, near 
the Hawaiian islands more than 2 Km of 4.5 Km/ 
Sec material was observed, and laboratory meas- 
urements made on samples from Hawaiian lava 
flows suggest that in this case the Layer 2 is part 
of the root of the volcano. This view is supported 
by the fact that the Layer 2 decreases in thickness 
away from the volcanic island. If Raitts (1956) 
results on Layer 2 are divided into two groups 
those with velocity above 4.9 Km/Sec have an 
average thickness of 1.05 Km while those in the 
lower velocity group have an average thickness of 

2.06 Km. The report does not state which 
stations are near islands, but it seems possible 

Jhat the two groups correspond to the Gaskell 
and Swallow (1952) classification. It is possible 
that all Layer 2 is volcanic material, but although 
there are many sea-mounts which could be sources 
of supply it seems unlikely that volcanic material 
covers the whole ocean floor. It is much more 
likely that the layer 2 remote from features such 
as sea-mounts and islands is some form of 
cemented sediment. The velocities observed for 
layer 2 are not incompatible with limestone. 
If layer 2 is a band of hard rock about 0. 1 Km 
in thickness underlain by 3.0 Km/Sec soft sedi- 
ment, there will be a reduction in the depth of the 

6.7 Km/Sec layer below the sea bed from an 
average 1.3 to one of 0.8 Km; the two extreme 
profiles are : 



VOLUME 12 


2.0 

5.5 
3.0 


Km/Sec 
Km/Sec 
Km/Sec 


0.3 
1.0 
0.0 

1.3 


0.3 
0.1 
0.4 
0.8 


Km 
Km 
Km 


The 
too 
the 
have 
18 1 
obsc 



Soft sediment 
Layer 2 
Soft sediment 



The value of 6.7 Km/Sec for the compressional 
velocity in the first well marked layer below the 
sea-bed is found in the Atlantic and Indian ocean 
as well as in the Pacific (Ewingctal 1954, Raitt 
1956, Gaskell and Swallow 1951, 1952, 1953). 
The widespread occurrence of a material showing 
the same seismic properties lead to the belief 
that the 6.7 Km/sec layer is some crystalline rock 
which is a fundamental part of the earth's crust. 
There are physical reasons for believing that the 
material is crystalline rock rather than limestone. 
The strength of the refracted waves observed from 
the 6.7 km/sec layer are large compared with those 
observed in land refraction measurements or 
limestone. Limestone generally is layered, which 
tends to make it a poor carrier of seismic energy, 
and it often has shale breaks and faults which 
attenuate seismic waves by back scattering. 
Furthermore, laboratory experiments show that 
limestone has a greater attenuation factor than do 
crystalline rocks, and there is a tendency for the 
velocity in limestone to decrease with depth, so 
that refracted waved are made weaker by bending 
of energy downwards. It is probable that the 
6.7 Km/sec is a layer of basic rock. The granites 
that are known do not possess velocities much 
in excess of 6 Km/sec. 

The characteristic ocean bed structure has an 
8.2 Km/sec velocity layer about 10-13 Km below 
the sea surface. This is quite different from the 
structure found beneath continents, where the 
Mohorovici discontinuity (the top of the 8.2 Km/ 
sec layer) is at 30-40 Km below sea-level. Seismic 
measurements on continents show much greater 
variation in the velocity of the layer immediately 
above the 8.2 Km/sec layer and they also have 
much less regular depth of overburden. 

The Challenger expedition made seismic meas- 
urements at two stations near the coast of the 
United States, to landward of the andesite line. 
These stations were in about 1500 m of water 
and there was no 6.7 Km/sec layer such as was 
recorded under similar conditions on the ocean 
side of the andesite line. Similar results were 
obtained at stations in the Southwest Pacific, 
north of New Zealand, where instead of 6.7 km/ 
sec, velocities 5.8-6.0 km/sec were observed. 



GEOLOGY AND GEOPHYSICS 

The Challenger measurements were not carried 
too long enough distances to show the depth of 
the Moho, but Officer (1955) and Eiby (1957) 
have found that an 8.2 Km/sec layer exists about 
18 Km below sea surface in this region. These 
observers also found a 6.0 Km/sec layer below 
5.0-5.7 Km/sec material. 

Only two measurements have been made in 
the Philippine sea, which is an interesting area 
because the water is as deep as the main Pacific 
ocean, and yet the area is to landward of the 
andesite line. The seismic measurements showed 
a layer with velocity 5.7 Km/sec to be within a 
few Kms of the sea-bed. The Moho was not 
reached, but the results suggest that the area 
is not typical oceanic, and that it may well be 
similar to the Southwest Pacific area to the north 
of New Zealand. 

In the Indian ocean Challenger found results 
similar to those in the Pacific for Stations to the 
East of meridian through Ceylon. A station on a 
sea-mount showed that the bulk of the seamount 
was made of material in which the compressional 
wave velocity was 4.3 Km/sec, which is what 
would be found for one example near the Ha- 
waiian Islands. At the Seychelles, which are made 
of granite, seismic results showed that the rock 
at the surface had a compressional wave velocity 
of 6-Km/sec, and that a considerable thickness 
of this rock existed. 

It does appear then, that oceans and continents 
are different in their vertical rock profiles, and 
that the andesite line is a marker of seismic as well 
as of chemical significance. The andesite line, 
in fact marks the limit of the permanent ocean 
basins. There is, however, good reason to believe 
in extensive areas of an intermediate type of 
structure, in which the Moho is about 15-18 Km 
below sea surface and where probably consid- 
erable thicknesses of granitic rock are present. 

REFERENCES 

Raitt, R.W., 1956, Bull Geol Soc. Amer. 67: 
1623-1639. 

Eiby, G.A., 1957, New Zealand D.S.I.R. Geophy- 
sical Memoirs. 

Officer, C.B., 1955, Trans. Amer. Geophys. Un. 
36: 449-59. 

Gaskell, T.F. and Swallow, J.C., 1954, paper 
presented at I.U.G.G. Rome Meeting. 

67 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Ewing, M., Sutton, G.H. Officer, C.B., 1954, Gaskell T.F. and Swallow J.C., 1952, Nature 

Bull. Seismol Soc. Amer. 44:21. 170 : 1010. 

Gaskell T.F. and Swallow J.G., 1951, Nature Gaskell T.F. and Swallow J.C, 1953, Nature 

167:723. 172:535. 



68 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



CONTINENTAL MARGIN OF THE SOUTHWEST PACIFIC: 
ADVANCING OR RETREATING? 

RHODES W. FAIRBRIDGEt 

Department of Geology, Columbia University, New York, U.S.A. 

(Abstract) 



Progressively younger fold-belts have been 
welded on to the eastern margin of Australia, 
apparently increasing the E-W width of the con- 
tinent 2400 miles in 600 million years, which 
represents a mean rate of 0.25 inch or 6 mm. per 
year. In the terminology of Stille, these units 
(Eo-, Paleo-, Meso-, and Neo-Australia) represent 
successive belts of orthogeosynclinal character: 
the youngest is the present zone of deep sea 
trenches coinciding with the "Andesite Line" 
that marks the present limit of "continental" 
andesites against the true, thalassocratonic 
Pacific. 

The problem arises in explaining the nature of 
the fairly deep marine basins that lie in the region 
between eastern Australia and the Andesite 
Line the "Melanesian Subcontinent." There 
is ever-increasing evidence of paleogeographic 
nature, that these basins (at least, in part) repre- 
sent former semi-continental areas that have 
been more or less recently fragmented and have 
suffered differential subsidence. Highly complex 
and varied submarine topography points to an 
involved history. Some observers therefore 
visualize a current break-down of the Melanesian 
region, rather than a progressive build-up. 

However, paleontological evidence fails to 
identify any rocks older than younger Paleozoic 
in the central (New Caledonian) belt of islands; 



and nothing older than the Tertiary in the eastern- 
most islands (Fiji, Tonga). The petrology of the 
older sediments in each belt gives no hint of 
earlier rocks of continental or granitic nature. 
Search by the writer and others has failed to 
uncover any secondary evidence of a long-lost 
Paleozoic or Precambrian basement here. 

Seismic work at sea by Russell Raitt on Ex- 
pedition CAPRICORN of the Scripps Institution 
of Oceanography in 1952-53 has shown that the 
typical subocean crustal thickness in the Fiji 
region is 10-20 km of basaltic characteristics, 
overlain by 1-2 km of sediment (demonstrated by 
coring, to consist essentially of reworked vol- 
canic-type muds). Earthquake seismology over 
this area points to the same conclusion, viz. an 
absence of a thick acid rock continental-type 
basement. Gravity observations by submarine 
made by Columbia University in cooperation 
with the Royal Navy and Royal Australian Navy 
demonstrated a profile across the area which is 
entirely compatible with this data. 

In conclusion, the Melanesian region shows 
evidence of progressive expansion to the east, 
at the expense of the true Pacific, but that repeated 
oscillations over the intervening area indicate 
"regeneration" of imperfectly differentiated and 
consolidated crust of intermediate thickness. 



t Presented by Dr. Roger Revelle. 



69 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



SHALLOW SUBMERGED MARINE TERRACES OF 
SOUTHERN CALIFORNIA 

K. O. EMERY 

University of Southern California, Los Angeles, California, U.S.A. 

(Abstract) 



Sounding profiles across the mainland shelf, 
island shelves, and bank tops of southern Cali- 
fornia show the presence of five separate flatten- 
ings that are interpreted as erosional marine 
terraces cut during times of low sea level of the 
Pleistocene Epoch. Similar terraces have been 
discovered recently in widely separated parts of 
the world, such as Japan, Guam, and the Persian 
Gulf, supporting the interpretation of their re- 



lationship to eustatic changes of sea level. A 
correlation diagram of the terraces of southern 
California shows that each one is deeper around 
offshore islands and banks than off the mainland; 
this is attributed to regional warping that from 
other evidence is believed to have begun in Late 
Miocene time. The warping indicated by the 
deepest terrace, at the shelf edge, amounts to 
about 140 feet per 100 miles. 



70 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Symposium: Mesozoic Orogeny in the Pacific 

Convener: o. w. GRINDLF.Y (New Zealand) 
MESOZOIC OROGENIES IN NEW ZEALAND 

G. W. GRINDLEY 

'Geological Survey, Wellington, New Zealand. 

(Abstract) 



The New Zealand geosyncline, a subsiding 
trough that probably extended east of southern 
New Zealand to Chatham Island and north- 
west of Auckland peninsula to New Caledonia 
and New Guinea, was a major tectonic feature of 
the late Paleozoic and early Mesozoic in the south- 
west Pacific. In the Permian, the geanticlinal 
ridge west and south of this geosyncline was 
capped by active volcanoes, that supplied fresh 
volcanic detritus to the Permian sediments and 
built up thick volcanic accumulations on the sub- 
siding flanks of the geanticline, Volcanism, at first 
mainly andesitic and basaltic, changed to andesite- 
dacite-rhyolite in the Triassic, and became prac- 
tically extinct at the end of the Triassic. The 
geanticlinal ridge rose rapidly through the Triassic 
and a wedge of coarse sediment (Hokonui facies) 
built out toward the geosyncline. In the late 
Triassic, a granitised core was exposed on the 
geanticline and supplied granitic and dioritic 
material to the geosyncline. From sequences ob- 
served in southern New Zealand, it is known that 
both shelf and geosynclinal sediments to a total 
thickness of many miles (estimates range from 10 
to 50) accumulated in the Permian-Triassic geo- 
syncline. It is currently considered by many New 
Zealand geologists that the Chlorite and Biotite 
schists in Otago province, along the Southern Alps 
and in Marlborough province, were formed by 
deep burial of this thick accumulation of geosyn- 
clinal sediments. The schists now form an anti- 
clinal arch and grade into Permian greywackes on 
the south-west (geanticline) side and into Triassic 
greywackes on the north-east (Pacific Ocean side). 
This suggests migration of the geosyncline axis 
away from the geanticline towards the Pacific in 
the Triassic. 

The New Zealand geosyncline was folded and 
elevated in the early Jurassic, as indicated by mid- 
dle and upper Jurassic sandy, carbonaceous, con- 
glomeratic and fresh water sediments in two flank- 



ing belts on either side of the axis of elevation 
(schist anticline). The western belt became part 
of the geanticline in the late Jurassic; the eastern 
belt continued to subside as a narrow geosyncline 
along the east coast from north Canterbury to 
East Cape until the upper Cretaceous. The grey- 
wacke sediments deposited in this geosyncline are 
a re wash of the older greywackes of the New Zea- 
land geosyncline. The metamorphic core (schist 
axis) of this geosyncline was exposed in the lower 
Cretaceous in Otago, where fresh-water beds 
contain schist boulders. Studies of sedimentary 
facies and thickness show that the axis of this 
East Coast geosyncline also migrated eastward 
towards the Pacific Ocean. In the late Cretaceous 
only a small area in the extreme north-east of 
New Zealand was truly geosynclinal. A variety 
of relatively thin, sandy, muddy, calcareous and 
bentonitic sediments accumulated on broad 
shelves flanking the mature geanticline which oc- 
cupied most of New Zealand. The sea gradually 
whittled away the geanticline in the late Cretace- 
ous and early Tertiary until the Oligoccnc. when 
only a few islands survived. 

Volcanism in the late Mesozoic included spilitic 
pillow lavas, dolerites and minor ultramafics in 
the small geosynclines in Northland and the East 
Coast; probably a line of andesite volcanoes on 
the Pacific side of the East Coast geosyncline; and 
rhyolite, quartz porphyry, andesite and dacite 
flows interbedded with fresh-water sediments on 
the geanticline. 

Compilation of the paleogeographic maps is 
complicated by the large (300 mile) most-Triassic 
clockwise transcurrent displacement postulated 
for the Alpine Fault. This fault displaces lower 
Mesozoic paleogeographic boundaries but is con- 
fined in the upper Mesozoic to the geanticline and 
so does not affect the later geosynclinal bounda- 
ries. 

71 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LEGEND 

Triassic 

Shelf Sediments 

Triassic 

Redeposited Sediments 

Triossic 
Chlorite Schist 



Upper Paleozoic ? 
Redeposited Sediments 
and Schist in Axial Zone 
of Ceosyncline 



SO 25 O 50 IOO ISO 

i miles 




12 



Fig. 1. Triassic Paleogeography. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



170* 



LEGEND 
Ufa Jurassic 
: ' . '. 3 Freshwoter Beds 

Jurassic 

Shelf Sediments 



|m Jurassic 

^ Redepostted Sediments 

|8| Jurassic > 
^ Dyke Complex 

Upper Jurassic Inferred 

Shoreline 

Lower Jurassic inferred 

Shoreline 




Fig. 2. Jurassic Paleogeography. 



73 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LEGEND 

Lower Cretaceous 
Freshwater Beds 



Lower Cretaceous 
Shelf Sediments 



Lower Cretaceous 
Rede posited Sediments 

Lower Cretaceous 
Volcanic Complexes 



Probable Position of 
Shelf Edqe 




74 



Fig. 3. Lower Cretaceous Paleogeography. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



LEGEND 

Upper Cretaceous 
Freshwater Beds 



Upper Cretaceous 
Shelf Sediments 



Upper Cretaceous 
Outer Shelf Sediment j 



Upper Cretaceous 
Volcanic Complexes 




Fig. 4. Upper Cretaceous Paleogeography. 



75 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PACIFIC AND VARISCIAN OROGENY IN INDONESIA. 
A STRUCTURAL SYNTHESIS 

TH. H.F. KLOMPE 

Geological Institute, University of Indonesia, Bandung, Indonesia.^ 



The development of the pacific orogeny in 
Southeast Asia clearly shows the great importance 
of this orogeny for the gradual consolidation of 
the borderlands of this part of Asia. The diastro- 
phism of the Malayan Orogen should be considered 
as the continuation of an orogenic zone known 
from the Asiatic mainland in Malaya, East Burma, 
Thailand, Yunnan and China. The Pegu Yoma 
of Burma forms a representative on the mainland 
of the Sumatra orogen. The Sunda and Moluccas 
orogens have their equivalents in the Arakan 
Yoma, the Chin- and Naga Hills and the Hima- 
layas. A study of the various granite occurrences 
and their possible ages in the southeastern part of 
the continent reveals that the different mesozoic 
and tertiary structural zones can be traced south- 
east into the Sunda Land area and make the 
western part of Indonesia an excellent example of 
continental zonal outgrowth, mainly consolidated 
by the various diastrophic phases of the pacific 
orogeny. 

A review of the stratigraphic and structural 
development of the Banda Geosyncline and a 
re-examination of the literature on the problem 
of the Banda Sea area lead to the conclusion that 
there existed in late paleozoic early mesozoic 
time a landmass in the eastern part of Indonesia, 
occupying at least the present Banda Sea area, 
the zone of the outer Banda arc and the area 
occupied by the Sula Spur. 

A process of regeneration of marginal parts of 
this Jand area started in the South (Timor) in 
permian lower triassic time and spread to the 
North (Ceram) in upper triassic time, resulting 
in the formation of the so-called "Banda Geo- 
syncJine". The sequence of strata of this geo- 
syncline shows no indications for participating 
in a pacific orogeny; stratigraphic gaps and 
changes in facies are the result of epeirogenic 
movements. The tertiary orogeny produced in 
the zone of the Banda Geosyncline intermediate 
type structures, assuming that the overthrust 
structures, reported from Timor and Ceram, are 
the result of gravitational tectogenesis in a sub- 



siding basin. Chapters on the Sahul Shelf area 
and the occurrence of an important belt of varis- 
cian orogeny in eastern Australia and northern 
Queensland make it acceptable that the pre-cam- 
brian nuclei of the Australian Continent should 
be continued over some distance to the North 
and Northwest, while the belt of variscian orogeny 
should be traced from northern Queensland to 
southern New Guinea, Ceram, the Sula Spur, the 
Aru Islands and Timor, including the late-paleo- 
zoic landmass in the Banda Sea area, which also 
should be considered as the result of the variscian 
orogeny. 

The main conclusion of the paper, the im- 
portant structural difference between the western 
and eastern part of the Indonesian Archipelago, 
forms the base for a preliminary geotectonic map 
of the area. The wellknown "Wallace line", 
between Borneo and Celebes, not only forms an 
important faunal boundary but is, according to 
this conception, also a very important structural 
boundary. 

Several points are mentioned to emphasize the 
great differences between West and East Indone- 
sia, which all can be explained by this synthesis. 
A few geological and geophysical problems are 
discussed from which it seems that they can be 
solved according this new line of thought. 

GENERAL INTRODUCTION 

The results of the tertiary alpine or himalayan 
orogeny, according to Westerveld (74-75) 
called the middle miocene Sunda orogen and the 
Moluccas orogen, shaped between the Late Cre- 
taceous and Middle Miocene, are occupying the 
area between the Sunda and Sahul shelves, (fig. 1). 

These shelves, being the partly submerged exten- 
sions of resp. the southeastern edge of the Asiatic 
and the northern and northwestern edges of the 
Australian Continent, are considered to be 
younger additions to the older continental nuclei, 
the so-called cratons. In other words both con- 
tinents have grown towards each other in these 



t Presently Department of Geology, Chulalongkorn University, Bangkok, Thailand. 
76 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 1. Sunda and North Australian Shelves with axis of Sunda Orogen (- 
according to Wester veld. 



) and Moluccas Orogen (- 



respective directions and the tertiar> or himalayan 
orogenesis actually resulted in welding these two 
continents together with the Sunda and Moluccas 
orogens (- v. Bemmelens Sunda orogen) as a 
scar between them. So the Sunda Shelf area in 
the West and the Sahul Shelf area in the East are 

now separated by an intervening belt of deep-sea 
basins and island-festoons, of, geologically speak- 
ing, a rather young age. 

The shelf-seas are generally less than 100 meters 
deep, although the edges of the shelves are indi- 
cated on the map by the 200 meter isobath, as is 



the common use. The islands emerging from the 
shelfseas arc mostly less than 1 ,000 meters high, 
those on the Sahul Shelf being particularly much 
lower than those on the Sunda Shelf. These 
shelves largely are considered to be old peneplains 
which under certain conditions could be formed 
on such a large scale. They are only gently warped 
by later epeirogenic movements, being more or 
less stable land masses with a low seismicity, low 
isostatic gravity anomalies, and no active 
volcanoes. 

Both shelf areas are usually considered as being 

77 



PROCEEDINGS OF THE NINTH PACTHC SCIENCE CONGRESS 



formed in the same way and, what is more im- 
portant, at the same time. The author agrees 
with the first supposition that both shelves have 
been growing steadily on account of the continu- 
ing orogenic processes which have in due course 
contributed to the enlargement of the respective 
continental nuclei, enlarging the cratons gradual- 
ly, adding all the time more or less stabilized 
zones to the continent. It is, however, the 
author's opinion that both shelf areas were 
structurally not formed at the same time, at least 
not those, usually indicated as the Sunda and 
Sahul shelves. The formation of the Sunda Shelf 
is mainly the result of consolidation and growth 
during the various mesozoic phases of the pacific 
orogeny, while the Sahul Shelf, and particularly 
the area of it covered by the Arafura Sea and its 
extension further West is mainly the result of the 
variscian orogeny of which the western part, now 
occupied by the Banda arcs of the Sunda and 
Moluccas orogens, participated in a later, mainly 
mesozoic, process of transformation or as Stille 
(51,52) calls it of regeneration. According to this 
author this process of regeneration implies a return 
of semi- or quasi- consolidated shelf areas into a 
geosynclinal stage, in other words a remobihza- 
tion of cratonic areas which is in general only 
possible as long as the quasi-cratonic and not 
yet the fully-cratonic stage exists. By this process 
of regeneration the mesozoic Banda Geosyncline 
was formed out of which, mainly in tertiary time, 
the Sunda and Moluccas orogens were formed. 
The best example of regeneration is known from 
the structural history of the Alps. This area was 
once, together with the Central European fore- 
land, transferred into a quasi-cratonic mass, but 
part of it was again unlike outer-alpine Central 
Europe, transferred into a mobile geosynclinal 
area, so that a new geotectonic cycle was started. 

The purpose of this paper is to give an up-to- 
date picture of the general structural development 
of both shelf-areas, to draw certain conclusions 
about the process of the formation of these shelves 
and about the orogenic cycles responsible for 
their formation. 

THE PACIFIC OROGENY IN 
WEST INDONESIA 

INTRODUCTION 

It was already in the 19th Century that von 
Richthofen drew attention to the fact that the 
eastern and south-eastern parts of Asia form an 
excellent example of the gigantic zonal structure 
of a continent, rejuvenating the further we rc- 

78 



move from the old pre-cambrian nuclei of the 
continent which are gradually welded together 
into larger stable or quasi stable areas. During 
further development of geologic research in these 
regions this old statement proved to be true 
everywhere so that it is now generally accepted 
that going East these pre-cambrian nuclei are, 
still on the mainland, surrounded by paleozoic 
orogens. Then follows a mesozoic orogenic zone 
which is now partly represented by mountain 
ranges in the coastal areas of East Asia, partly by 
structures on the adjacent islands east and south- 
east of the continent. Still further east and south- 
east we reach the tertiary mountain chains, partly 
covered by the sea, in certain places even by a 
deep-sea, of which only the outer zone reaches 
above the level of the ocean and forms the outer 
continental fringes represented by arcs of islands. 
These border chains form the youngest orogens 
with deepsea-troughs in front, which surround 
these island arcs almost completely and form the 
true border with the Pacific Basin proper, a border 
in the geologic literature known as the "Andesite 
line". In few places, e g. in the Indonesian 
Archipelago, more detailed geological research 
has been carried out and a more detailed zonal 
structure could be fixed because older rocks, 
syntectonic plutons and postvolcanic phenomena 
particularly occur on the inner side and the 
younger folded sediments on the outer side of 
these orogenic zones. 

STRUCTURAL IMPORTANCE OF THE PACIFIC OROGENY 
FOR SOUTHEAST ASIA 

In a paper submitted to the session of the 
International Geological Congress in Moscow 
(1937), Vialov (70) separated the mesozoic phases 
of diastrophism as a separate orogenic system 
from the alpine-himalayan system under the name 
of pacific system emphasizing with this name 
the importance of this orogeny for the Pacific 
area. 

In Central Asia the results of this mesozoic 
orogeny can best be studied in the Transhimala- 
yan Ranges which follow the Southern border of 
Tibet, arriving in NW Yunnan. Here the W-E 
trend changes into a southern one and soon the 
system diverges, forming an eastern branch 
between the massifs of South China and Thailand- 
Cambodja, and a southern branch between those 
of Gondwana and Thailand-Cambodja. The 
former curves northward, forming the Pacific 
border of Asia (Teilhard de Chardin, 60; Froma- 
get, 22). The latter extends southward across 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Burma (Shan States), the Mergui area and south- 
eastward to the Sunda Land. 

The best up-to-date review on the various 
orogenic phases was published by Rutten (46) in 
his paper on "Frequency and Periodicity of oro- 
genetic Movements". For our discussion on the 
importance of the pacific orogeny causing the 
gradual development and growth of Southeast 
Asia the following mesozoic phases of diastro- 
phism are of importance: 

a. a labinian phase between the Middle and 
Upper Triassic, particularly important for 
the structure of Indochina (indosinian). 

b. an old cimmerian phase between the Tn- 
assic and Jurassic, also of main importance 
for Indochina (indosinian). 

c. a young Cimmerian phase between the Jur- 
assic and the Cretaceous which is particu- 
larly reported from the Pamirs, Kunlun, 
China, Burma, Thailand, Malaya and Indo- 
nesia (ycnshanian). 

d. an austrian phase between the Lower and 
Upper Cretaceous resulting in unconformi- 
ties in the Hindukush, Japan and Indonesia 
(yenshanian). 

c. a laramic phase between the Cretaceous and 
the Paleogcnc which up to now is reported 
from Japan, Central and Southern China 
and Indonesia (ycnshanian). 

The occurrence of these various mesozoic 
phases of diastrophism demonstrates clearly the 
rejuvenation of the folds to the South and South- 
east with main results of the labinian and old 
cimmerian phases in Indochina and of the Cim- 
merian, austrian, and laramic phases further 
South in Burma, Thailand, Malaya, Borneo and 
Sumatra. 

In the "Pulse of the Earth" Umbgrove (65) 
publishes a world map upon which a chronologi- 
cal analysis of the continents is given. On this 
map the regions of older "alpine" diastrophism, 
in fact those dislocated by the mesozoic diastro- 
phic phases are pictured as a separate orogenic 
cycle. From this map it can clearly be seen that 
the influence of the mesozoic orogeny was strong- 
est in the area around the Pacific Ocean. Recent 
geological research in the areas along the western 
border of this ocean has proved that the influence 
of this orogenesis in the Japanese Islands, China, 
Formosa, the Philippines, Malaya and Indonesia 
is of far greater importance as is suggested by 
Umbgrove's map. 

From the results of the geological exploration 
in the Central Asiatic Mountains by Norin, during 



the Chinese-Swedish-Expedition under the 
Leadership of Sven Hedin, between the years 
1928-1931, it became clear that the mesozoic 
orogenic cycle plays also an important role in the 
Central Asiatic Mountain Ranges. 

A gradual increase of the importance of this 
cycle of diastrophism towards the Pacific could 
be clearly investigated, in such a way, however, 
that the variscian orogeny remained the main 
period of deformation for these mountain ranges. 
Reviewing the publications on the structure of 
the eastern and southeastern part of China it is 
no surprise that geologists studying the structure 
in this part of the continent hardly ascribed any 
importance to the variscian orogeny for these 
regions, because the pacific orogeny caused the 
bulk of the structural features of this area. 

Only rather recent Lee ( 37) emphasized at the 
18th Session of the International Geological 
Congress in London (1948) the importance of the 
laramidc movement and considers it as a very 
important event in China, and in certain provinces 
it is even the main mountain building movement. 
Only when we turn further West, e.g. in the region 
of the Tsinglingshan, we realize that we have to 
do with much older structures which were formed 
during the Lower and Upper Paleozoic. 

In one of the Geological Memoirs of the 
Geological Survey of China (Serie A, Number 20, 
Chungking) entitled "On major tectonic forms of 
China" Huang (29) subdivides the mesozoic 
orogenesis in two phases, an older indosinian 
and a younger yenshanian phase, of which the 
first one comprises the time interval Middle 
Triassic- Lower Jurassic and the second cycle the 
remaining part of the Mesozoic. Huang subdi- 
vides the indosinian phase into two sub-phases 
which are the same as Stille's labinian (a) and old 
cimmerian (b) phases; the ycnshanian phase is 
subdivided into three sub-phases, respectively 
corresponding with Stifle's young-cimmerian 
(c) austrian (d) and laramic (e) phases. In the 
Triassic of Indochina two distinct unconformities 
are distinguished, an older one at the base of the 
Upper Triassic and a younger one at the base of 
the Jurassic. These two unconformities indicate 
the occurrence of two orogenic phases. Accord- 
ing to Fromaget these are the most important 
ones in the area and are responsible for the 
mountain structures still occurring in Indochina. 
This indosinian (Fromaget, Huang) phase of 
mountain building resulted in rather strong 
folding, characterized by extensive overthrusts 
in various places, leading to the formation of 
extensive sheets and magmatic activity (granites). 

79 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRFSS 



The influence of this orogeny reached till southern 
and central Yunnan. Also in the southeastern 
part of China the results of young triassic dias- 
trophism occur rather frequently and in northern 
China there exist in many places unconformities 
between the Jurassic and Triassic. Still further 
North unconformities between the older deposits 
and the Jurassic coalseries in Jehol and Man- 
churia prove the occurrence of mountain building 
movements, the age of which could not yet 
exactly be determined. 

Fromaget (22) is of the opinion that the entire 
Pacific border of the Asiatic Continent belongs 
to the Indosinides. But others, e.g. Teilhard de 
Chardin (60), believe that both phases, as well 
the old as the young mesozoic, were active in the 
Pacific border region. The former should be 
responsible for the formation of the mountain 
system of Kwang-si with post permian pre jur- 
assic granites; the latter formed that of Kwangtung 
with post Jurassic granites (e.g. those of Hong- 
kong). Teilhard de Chardin distinguished on his 
map these two groups of granitic intrusions as 
resp. the Mongolian and Yenshan granites. The 
Yenshan granftes often intruded into the Mongo- 
lian group. These two phases consolidated in 
the course of the Mesozoic the Pacific border of 
the Asiatic Continent. The younger tertiary and 
quaternary cycle emigrated further toward the 
Pacific Ocean creating the East Asiatic island 
festoons. From this we might conclude that the 
old mesozoic indosmian phase of orogeny was 
not only important for Indo-China but also for 
large parts of China. However, many years of 
geological research in E and SE Asia will still be 
required in order to obtain a clear picture of the 
real character and influence of this indosinian 
phase of mountain building, particularly because 
the results of the older phases were blotted out 
by the younger ycnshaman disturbances, which 
were more important in these northern areas. 

The yenshanian phase of orogeny is charac- 
terized by a distinct unconformity at the base of 
the Cretaceous. In the Western Hills of Peking 
this unconformity is not so well pronounced, but 
is much better developed in the eastern continu- 
ation of the Tsinglingshan. Unconformities of 
similar age occur in the area of the lower course 
of the Yangtse river. These pre-cretaceous un- 
conformities form a frequently occurring feature 
in the geology of eastern China, the intensity of 
this phenomenon is, however, rather varying from 
place to place. This yenshanian phase of orogeny 
is too young to be considered as a post-phase of 

80 



the variscian orogeny and to old to be included 
into, the alpine-himalayan orogeny. 

Nevertheless it has been of such great influence 
on the local structure of eastern China that it 
should be distinguished as a separate phase. 
Because the results of this orogeny became first 
known from the Western Hills of Peking, which 
Chinese geographers indicate with the name 
Yenshan, geologists from the Geological Survey 
of China have described these phenomena as the 
result of the yenshanian orogeny. These yensha- 
nian movements started already in upper Jurassic 
time. 

In West Yunnan (SW. China) the mam folding 
took place after the Jurassic. The fact that 
neither here nor in the area of the Shan Plateau 
further to the South, cretaceous or old-tertiary 
deposits have been found, makes it rather difficult 
to give this folding phase an upper time limit. 
Several geologists consider the deformation of 
western Yunnan as a result of the himalayan or 
tertiary orogeny. The fact, however, that the 
old-tertiary deposits of North Burma, with thick- 
nesses varying between 7,000 and 1 2,000 meters, 
are mainly of fluviatile or dcltoidic origin and that 
the basal conglomerates of the Tertiary are com- 
posed of crystalline schists and gneises, indicate, 
that the crystalline massives of western Yunnan 
were already elevated areas before the beginning 
of the tertiary orogeny. We might conclude from 
this, that the western part of Yunnan was already 
submitted to diastrophic movements and emerged 
before the beginning of the Tertiary and it is very 
likely that this happened during the yenshanian 
cycle of orogeny. In Burma, geologists have come 
to similar conclusions and the dislocations of the 
Shan Plateau were considered by them as the 
result of the yenshanian orogeny. We conclude 
that the alpine orogeny as described and sub- 
divided by H. Stille (51) in his "Vergleichende 
Tektonik" in young-, old-, and pre-tertiary stages, 
should at least in East Asia no longer be considered 
as a single period of orogeny but should in fact 
be subdivided in two mountain building periods, 
the pacific and the alpine-himalayan cycles, of 
which the first period can be subdivided in two 
phases, including two or more sub-phases each. 

The first phase is the old-cimmerian, conform 
its structural importance for Indo-China indicated 
as the indosinian; the second phase is the yen- 
shanian or, on account of its importance for the 
structure of China proper, the sinian phase. With 
their respective sub-phases they form the pacific 
cycle of orogeny which has been of such great 



VOLUML 12 



GEOLOGY AND GEOPHYSICS 



importance for the consolidation of the eastern 
and southeastern Asiatic borderlands. 

The second mountain building period, the al- 
pine-himalayan orogeny has her main develop- 
ment in the Tertiary and is frequently also indi- 
cated as the tertiary orogeny. This orogeny is 
mainly responsible for the formation of the outer 
fringes and island arcs of the Asiatic Continent. 

STRUCTURAL DEVFLOPMI-NT OF THL SUNDA LAND 
AREA 

The present Sunda Shelf area can be subdi- 
vided in an old central landmuss, comprising 
the Malay Peninsula, the Riomv-Lingga Archi- 
pelago, Bangka and Bilhton. the Kanmundjawa-, 
Karimata-, Tambelau-. Anambas-, and Natuna 
Islands, the western part of Borneo, now forming 
an old peneplain, and the more labile marginal 
parts which still have been subjected to the various 
phases of the young pacific and alpine-himalayan 
orogenies, represented bv the remaining parts of 
Borneo, Bawcan Island, Java, Madura und Su- 
matra. It is the partly submerged southeastern 
outgrowth of the Asiatic continent, being con- 
nected with it by the Malay Peninsula and the 
Isthmus of Kra. 

There exists no doubt about the gradual struc- 
tural development of this Sunda Land area. 
Whether we accept the conceptions of Stifle, 
Umbgrove, Westerveld, or van Bemmelen, they 
all come in their various publications and struc- 
tural maps to a distinct zonal structure and re- 
juvenation in southeastern direction. Next to 
minor variations in the details of the various 
orogenetic zones there is a considerable di (Terence 
of opinion in regard to the origin of this zonal 
structure as supposed by Stillc, Umbgrove, and 
Westerveld on one, and of van Bemmelen, on the 
other side. The conceptions of the first group of 
scientists are based upon a gradual growth of 
the annamitic and indo-malayan chains around 
an old pre-cambrian massif, occupying Cambodia 
and eastern Thailand ("Cambodian mass" of 
Suess (58) and renamed "Indosiman mass" by 
Fromaget (21), caused by erogenic forces acting 
since the Late Paleozoic and emigrating for one 
reason or another from the SE. part of the Asiatic 
Continent. 

Van Bemmelen, however, is of the opinion that 
this zonal structure is caused by emigration of 
orogenic waves originating from an "undation 
centre", in this particular case his so-called 
'"Anambas-centre", from which the various 
orogens spread outwards and successively moun- 



tain systems came into existence forming ever 
widening arcs. We will see that when eliminating 
the youngest narrow zones of outgrowth, the 
Sunda and Moluccas orogens of Westerveld, 
forming together van Bemmelens Sunda Mountain 
System, the remaining part of the Sunda Land 
area was formed as the result of the youngest 
(sinian or yenshaman) cycle of the pacific orogeny. 
However, further South from Yunan, and in 
the Sunda I and area proper it becomes rather 
difficult to date the results of the various phases 
of the pacific orogeny e.g. in Thailand, Malaya 
and Indonesia. This will not say that they become 
less important in those areas but considerable 
gaps in the stratigraphic sequence of the Mesozoic 
make it often impossible to give the exact age of 
the phases of diastrophism. Fortunately in most 
of the areas where these gaps occur, denudation 
has advanced so much that we are able to use the 
occurrence of syn- or post-tectonic granites to 
obtain data about the relative age of the main 
folding phase. Also in these cases, however, 
gaps in the stratigraphy of a certain area usually 
allow only the dating of the maximum and mini- 
mum ages of the granite and of the phase of dias- 
trophism with which they are connected. Ab- 
solute age determinations with radio-active 
methods will contribute considerably to solve 
the problem of the ages of the granites connected 
with the various phases of diastrophism, but up 
to now very little has been achieved in that line 
Scliurmann et ah (47). 

In the southeastern coastal provinces of China, 
where Jurassic sediments show strong diastro- 
phism, the occurrence of granites in connection 
with this folding demonstrates clearly that the 
sinian (or yenshanian) phase of orogeny was much 
more active than further West. 

During the 4th Session of the Pacific Science 
Congress at Bandung (1929) attention was drawn 
to the great importance of the occurrence of 
young mesozoic granites and a young mesozoic 
phase of mineralization for SE. Asia. In Thailand 
the Paleozoic is folded conformably but the 
proper age of the folding-phase cannot be in- 
vestigated, but is definitely post-paleozoic. The 
various granite bodies which occur in the folded 
strata show all the same N-S trend as the folds. 
Usually they occur in the cores of the anticlines 
but locally they also break through the structures. 
Their occurrence points to a strong connection 
between the folding and the formation of these 
granites. The first phase of orogeny in Malaya 
occurred at the end of the Permo-Carboniferous, 
terminating the preceding geosynclinal evolution 

81 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



in the eastern part of the peninsula by an uplift 
and formation of plutonic rocks. To these older 
plutonics presumably belong parts of the igneous 
complexes in the eastern part of the peninsula 
(East of the Main Range), but later tectonics and 
magmatic activity render it impossible to dis- 
tinguish these older granites. Thereafter, renewed 
geosynclinal subsidence caused the transgression 
of the sea and the deposition of a flysch-like 
formation of upper-tnassic age. Intercalated 
polymict conglomerates contain detritus of the 
permo-carboniferous formation (e.g. pebbles of 
silicious shales with radiolarians, shales, acid 
eruptive rocks), and also boulders of pre-triassic 
granites. 

Further West the unconformity between both 
formations is less clear, and locally sedimentation 
might have continued uninterruptedly (Klompe, 
30). 

Then followed a second period of mountain 
building and intensive folding of triassic quartzites 
and slates together with the intrusion of granites 
still represent the most striking structural and 
magmatic features of the peninsula. These 
various granitic bodies show a similar position 
as those further North in Thailand. These are 
now exposed as the Main Range Massif, some 
300 miles long and as much as 30-40 miles wide, 
rising in places to more than 7,000 feet above sea- 
level. This tremendous mass of granite repre- 
sents only the exposed upper part of an enormous 
granitic root. The tin-granite batholiths of Bang- 
ka and Billiton further SE. some of the granite 
occurrences further East (Borneo) and those 
further North in Thailand are all eminencies on the 
back of the same granitic mountain root. Though 
it is not difficult to assign this folding together 
with the intrusion of the granite bodies a post 
triassic age, it is not possible to fix the age of this 
diastrophic and magmatic phase more accurately 
because no marine deposits of Jurassic or creta- 
ceous age have been discovered. 

This shows that the Malay Peninsula forms part 
of the Pacific Mountain System, distinguished by 
Vialov (70) . We might tentatively date this major 
orogenic revolution in the Sunda Land area as 
"end of the Triassic", although it is also possible 
that it occurred in the Lower Jurassic. The 
intrusion of the tin granites presumably occurred 
later in the Jurassic, but before the Cretaceous. 
On account of the similar position of the Thailand 
granites we might also accept tentatively a post 
triassic, but pre cretaceous age for the diastrophic 
and magmatic phases in Thailand. In case this 
correlation is correct the main phase of orogeny 

82 



in Malaya and Thailand is of the same age as the 
sinian (or ycnshanian) orogeny of East China. 
Malaya forms the western part of the Sunda Land 
of which it forms an integral part to which younger 
diastrophic phases added younger orogenic zones 
and the whole process resulted in a steady out- 
growth of the Asiatic Continent to the Southeast. 

During geological investigations in West 
Borneo by Zeylmans v. Emmichoven and van 
Bemmelen (77, 3), indications were found that at 
least the larger part, if not all, of the granites in 
this area have an upper Jurassic age. In several 
places the granites are overlain b\ a lower creta- 
ceous conglomerate in which pebbles of granite, 
while this type of granite also occurs intrusive 
in the possibly Jurassic limestones of the West 
Borneo Mountain System. 

When we accept that the granites of Thailand, 
Malaya and the Tin-islands, which are definitely 
of post triassic age, can be correlated with the bulk 
of the Borneo granites, than all these granites 
should be ascribed an upper jurassic age and 
should be considered to belong to the sinian (or 
ycnshanian) phase of orogeny. 

In the Indonesian Archipelago we are faced 
with the youngest zones of this gradual outgrowth 
of the Sunda Land area (e.g. SE. Asia). Here 
the youngest tertiary orogeny is developed in a 
beautifully arc-shaped zone which towards the 
N. can be traced into the mountain ranges on the 
mainland of Asia, towards the E. this zone is 
thought to have its continuation in the Banda 
arcs, than through Celebes and further North to 
the Philippines. This youngest zone of orogeny 
(Sunda and Moluccas orogens (Westerveld), or 
Sunda Mountain System (v. Bemmelen) brings 
the Sunda and Sahul shelves almost in contact 
with each other with only this young zone of 
diastrophism as a scar between both. In several 
of his publications and books on the structural 
development of Indonesia, van Bemmelen (4, fig. 
73; 5, fig. 10; 6, fig. 12) publishes a skctchmap 
(fig. 2) on which the occurrences and ages of 
granitic rocks in the various orogenic zones of the 
Indonesian Archipelago are schematically indi- 
cated. From this map we see that the Barisan 
Geanticline is characterized by cretaceous granites 
with on the eastern side a zone of Jurassic and 
West of it a zone of middle tertiary granites. 
Reviewing the situation of the various granitic 
bodies more in detail we find that Jurassic granites 
are only known from two localities in East Sumatra 
(Tigapuluh Mts and Bt. Batu, close to Palembang) 
and tertiary granites only from two localities in 
South Sumatra (e.g. Bengkunat massif). All 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Crystalline basement complex granites 
Permotnassic granites 



Jurassic granites 
Cretaceous granites 



Mid-terlifl'-y granites 
Ltle tertiary granites 



Fig. 2. Distribution of granitic rocks in orogenic belts after van Bcmmelen (1949). 



other granites are with the exception of a few of 
uncertain age, believed to be of Upper Mcsozoic 
age. 2 Only from three of these the Rawas, 
Gumai, and Garba granites, a definite cretaceous 
age could be established. The Rawas granites 
penetrate Jurassic slates; the Gumai granite is 
transgrcssively overlain by an eocene conglomer- 
ate containing granitic material; and the Garba 
granite is intrusive in the cretaceous Garba Layers 
(van Bemmelen, 2). From all the other occur- 
rences we only know that they have a post triassic- 
pre tertiary age and that their petrographic charac- 
ter is different from that of the Jurassic tin- 
granites further East, so that it is very likely that 
all these granitic bodies are Upper Cretaceous, 
characterizing the laramic or youngest mesozoic 
phase of the pacific orogeny. 

A more carefull and closer determination of 
the age of these granites is not possible because 
in most of the areas where granites occur no 
Jurassic or cretaceous deposits were found. On 
account of this it is possible that slight pre- 
orogenic movements occurred already in the Jur- 
assic (young Cimmerian) and continued during 



the Lower Cretaceous, leading to a paroxysmal 
orogenic and magmatic phase (laramic) in the 
Upper Cretaceous, resulting in a general geanti- 
clinal uplift, folding, and the intrusion of granites 
mainly in the cores of the broad anticlines. 

In Borneo, where in the western part the Jur- 
assic granites of the sinian orogeny are well 
developed, cretaceous granites occur only in the 
Meratus Mts. in the southeastern part and pos- 
sibly also on Pulu Laut. In the Meratus Mts. 
the granite is younger than the Jurassic Alino 
formation and the lower cretaceous Paniungan 
beds, but older than the upper cretaceous 
Manunggul formation. All other granite oc- 
currences in North-, Central-, and East-Borneo 
are tentatively considered as of tertiary age. 

From these occurrences in Borneo, the oc- 
currence of tertiary granitic rocks on Java and the 
few localities of tertiary granite in S. Sumatra 
we conclude that another, still younger orogenetic 
zone, now forms the marginal border of the Sunda 
Land or a row of islands in front of it. Some 
parts of this youngest orogenic zone (Sunda- 
Moluccas orogen of Westerveld) have apparently 



2 Musper (40) reports from Central Sumatra the occurrence of a pre-permian granite North of the Gk. Bulat. Recent 
fieldwork (1957) revealed, however, that the granite is only represented by a strongly weathered arkosic sandstone be- 
longing to the tertiary Quartzsandstone Formation. The granite, possibly underlying this arkosic sandstone, is con- 
sequently overlain by tertiary quartzsandstones and not by permian limestones. It forms part of the large granite 
mass approximately 350 m. to the North, which is of cretaceous age. 

83 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



J o* rw>s(/af or THE SUMATRA ORO- 



PAiAtOttNf ANO PfRHAPi, OiDf 
AND BVTHt Df 



PfttHIMA&iY tNOfO AT THf IND Of THC. 



OCAll) r& Thf MIPOi.1 MlOC[H[ 



. 

mtHKfT OF Mio- Foment DCPOSI** WCAUY sr/u *T*OOIY o/srtsAmo 
Of 7nr MAIAVA oRoGEN , MAIN ACT of f OLD/KG AMD *>iuro#/<: ACTIVITY LATI JURAWC 

I-I^ t-MPALOfH CON1PLHX OF HOKTHtRK CtHTRAL BoRNl 0, STRONGLY rO'Ofti lATt P/UAfOZOK. TO fOCfflf [>l POSITS IH 

' 



flTS OF E*V HALHAHtUIA AHD NO*TH Mr* 6ui 




Fig. 3. Westervcld's tectonic Scheme of the East Indies. 



already been eroded deep enough to expose their 
syntectonic granites (S. Sumatra, Java, E. Borneo) 
while in others, e.g. on the islands off the West- 
coast of Sumatra denudation has not yet suf- 
ficiently advanced to expose these synorogenic 
granites. Westervelds tectonic sketchmap of the 
East Indies (74, 75) gives a fairly good impression 
of this gradual zonal outgrowth of SE. Asia. 
He distinguishes on his map (fig. 3) the following 
four orogens, which in ever widening arcs spread 
themselves towards the Indian Ocean: 

a. The Malaya orogen with a main act of fold- 
ing and plutonic activity in the Late Juras- 
sic. It connects the folds of the Sunda 
Shelf area through the Malayan Peninsula 
and SW. Thailand with synchronous struc- 
ture and plutonics of SE. and E. Burma 
(Shan States). It is built up largely by per- 
mo-carboniferous and upper- triassic sedi- 
mentary, and also volcanic rocks, penetrated 
by numerous masses of granites and tonalitic 
intrusives. 

b. The Sumatra orogen, characterized by 
cretaceous to palaeocene and perhaps older 
mesozoic folding and by the development 

84 



of young mesozoic plutonic rocks (in part 
cretaceous). Along the southeastern, south- 
ern and southwestern margins the folds of 
the Malaya orogen pass into a younger pre- 
tertiary mountain belt exposed in SE. Borneo 
(Meratus-Bobaris Mts.), the South Seraju 
Mts. in Central-Java, and in the main range 
of Sumatra. The folded cretaceous beds of 
Central-Borneo and SW. Sarawak occupy 
an intermediate position between the older 
folds of West Borneo and the younger ones 
of the Embaluh Complex, and might be 
compared orogenically with the folded 
Cretaceous of SE. Borneo (Meratus Mts.). 

c. The Moluccas orogen, characterized by the 
development of strongly folded overthrusted 
late paleozoic, mesozoic, and old tertiary 
rocks, and by the large scale development of 
ultra-basic intrusiva of presumably young 
mesozoic to early tertiary age. The creta- 
ceous and palaeogene folding and magmatic 
activity with subsequent lateral compression 
during the Late Tertiary, affected the zone 
now occupied by the outer row of islands 
West of Sumatra, by Timor and the outer 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Banda arc, and by the vast area of the 
Eastarcs of Celebes, on a considerable scale, 
d. The Sunda orogen takes an almost median 
position between the Moluccas and Sumatra 
orogens and appears as a scar of impressive 
length, healed by miocene volcanism. This 
belt developed into a longitudinal strip of 
zones of collapse, which were gradually 
filled up with a thick sequence of andesitic 
lavas, breccias and agglomerates, and by 
miocene sediments. At the end of the 
Miocene, this mixed series was rather 
strongly folded and subsequently intruded 
along its whole extension by dykes and 
bosses of andesitic and dacitic rocks, and by 
dioritic and granitic melts. Along its course 



it passes through the western coasl ranges 
of Sumatra, the Southern Mountains of 
Java, the Lesser Sunda Islands, the loop- 
shaped inner Banda arc, the islands in the 
Flores Sea including Salajar, the Westarcs 
of Celebes, and finally through the Sangihe 
Islands into the central part of Mindanao. 
The first two erogenic phases of WestervelcTs 
scheme can be compared with those of the sinian 
or yenshanian cycle of the pacific orogeny, the 
two last ones with diastrophic phases of the 
alpine-himalayan orogeny. 

CONCLUSIONS 

The development of the pacific orogeny in SE. 
Asia clearly shows the great importance of this 



Foldmarqms 

I- i Var isc ian foldi ng 
2-2 Cimmerian >t 
3-3 Ifiramic t , 

4-4Tertiary ,, 

Direction of 
move me n \ s 




Fig. 4. The zonal outgrowth of Southeast Asia (according to Stille, slightly altered by Klompe) 



85 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



orogeny for the gradual consolidation of the 
borderlands of this part of Asia. The diastro- 
phism of the Malayan orogen should be considered 
as the continuation of that known from the 
Asiatic mainland in Malaya, East Burma, 
Thailand, Yunnan and China. The Pegu Yoma 
of Burma forms a representative on the mainland 
of the Sumatra orogen. The Sunda and Moluccas 
orogens have their aequivalents in the Arakan 
Yoma, the Chin- and Naga Hills and the Hima- 
laya. A study of the various granite occurrences 
and their possible ages in the southeastern part of 
the continent reveals that the various mesozoic 
and tertiary structural zones can be traced further 
southeast into the Sunda Land area and make this 
area to an excellent example of continental zonal 
outgrowth, mainly consolidated by the various 
diastrophic phases of the pacific orogeny. Sum- 
marizing, the following structural zones can be 
distinguished in this southeastern part of Asia 
(fig. 4): (Stille. 52; Klompe, 31). 

1. The pre-cambrian and partly also caledo- 
nian, consolidated nucleus of Indo-China; 
Suess ''Cambodian mass" (58) and renamed 
"Indosinian mass" by Fromaget (21). 

2. A zone of variscian orogeny, particularly 
important for Indochina and possibly reach- 
ing till tne northeastcrnmost part of the 
Malaya Peninsula. 

3. A zone of Cimmerian orogeny including 
"Indosinides" and the sinian or ycnshanian 
folds of E. Burma, Thailand, Malaya, North- 
east Sumatra, Bangka, Billiton and West 
Borneo. 

4. A zone of laramic folding which can be 
traced from Burma (Pegu Yoma) through 
Sumatra and Java to SE. Borneo (Meratus 
Mts.) and is possibly also developed in the 
folded cretaceous beds of Central Borneo 
and SW. Sarawak. 

5. A zone of tertiary diastrophism which can 
be traced from the Himalayas through W. 
Burma (Arakan Yoma), Sumatra and Java 
to East Indonesia. From there the north- 
ern continuation of this zone might be 
looked for in the eastern part of Mindanao. 

THE VARISCTAN OROGENY IN EAST 
INDONESIA 

INTRODUCTION 

The phisiographic character of the eastern part 
of the Indonesian Archipelago is entirely different 
from that of the western part and there is no doubt 

86 



that a difference in structural development 
between these two parts is at the base of this 
striking difference. 

The eastern part of Indonesia can be subdivided 
in the following structural units: 

a. Melanesia (Pacific mass till the "Andesite 
line"), 

b. The Irian-Halmahera orogcnic zone, 

c. The Sula Spur, 

d. The tertiary Banda-Celebes orogenic zone, 

e. The Sahul Shelf, and 

f. The Australian Continent (Gondwana). 

A discussion of the nature of the Pacific mass 
and the Irian-Halmahcra orogenic zone is outside 
the scope of this paper. The author's conception 
in regard to this orogenic zone is ampl> discussed 
in his paper on: 'The structural importance of 
the Sula Spur" (Klompe 30, p. 24). 

For a detailed discussion of the geology of the 
Sula Spur the author refers to the same article 
which was written as a contribution to the VIII 
Session of the Pacific Science Congress in Manila 
(1953). 

In that contribution the Sula Spur is considered 
to represent the western end of a variscian folded 
belt. This consolidated spur is supposed not only 
to be responsible for the remarkable double-loop 
in the tertiary Banda-Celebes orogenic zone, but 
it also forms the structural boundary between this 
orogenic zone, South, and the Irian-Halmahera 
orogenic zone, North of the Sula Spur. 

However, the conclusion in connection with 
the double-loop structure of the tertiary orogen 
was not entirely to the satisfaction of the author 
and in this second part a short discussion on the 
stratigraphy and structural features of the eastern 
part of the Banda Geosyncline will be followed 
by some speculations about the possible nature 
of the Banda Sea during the Mesozoic. The 
* results of these suppositions will be considered in 
connection with the structural development of 
the Sahul Shelf as the marginal border of the 
Australian Continent. It is the authors opinion 
that this shelf zone occupied a more extensive 
area shortly after the variscian orogeny but that 
the western part was involved in a late paleozoic- 
early mesozoic process of regeneration by which 
the Banda Geosyncline was formed, out of which 
in tertiary time the Banda arcs were pressed up. 
The Sahul Shelf should be considered as a much 
older shelfcomplex than the Sunda Shelf and it is 
this feature which in a way should be put respon- 
sible for the remarkable difference in structure 
between the western and eastern parts of the 
Indonesian Archipelago. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



THE PRE-TERTJARY DEVELOPMENT 
OF THE BANDA GEOSYNCLINE 

INTRODUCTION 

The central Banda Basin is in its eastern part 
surrounded by two nearly parallel arcs of islands, 
a volcanic inner arc and a non-volcanic outer 
arc. The inner arc consists of a number of small 
islands of which some still show volcanic activity, 
others are typical coral-islands (fig. 5). With 
the exception of the Gunung Api, which rises 



from the flat bottom of the basin at a depth of 
4,500 m. all other islands rise from submarine 
ridges, which according to the bathyrnetric-map 
of the Snellius Expedition show an kk en echelon" 
arrangement (e.g. the Siboga and Luymes ndges). 

The outer arc is the result of a geanticlinal 
uplift, approximately 100-200 KM in width, built 
up of a series of crumpled mesosoic geosynclinal 
deposits with typical thrust-phenomena and 
without active volcanism. In the back part of 
this geanticline occurs a longitudinal depression. 




too- jooo w 



Fig. 5. Bathymetric Chart of the Eastern Part of the Indonesian Archipelago. 



87 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



In the Tanimbar Islands the width of this depres- 
sion is a few tens of kilometers, in the Kai Islands 
it is about 100 kilometers wide and becomes 
rather narrow in the Robot- Masiwang Graben 
in East Ceram. 

The similarity in stratigraphic and geologic 
development of these islands and the upper tri- 
assic transgression occurring in most of them lead 
Wanner to the conclusion that they have 
developed from a more o r less continuous sedi- 
mentary basin, since that time known in the litera- 
ture as the Banda Geosynchne (iig. 6). Concep- 
tions in regard to the actual course of this geo- 
syncline are, however, rather varying, but in 
general, it is now accepted that, based on the 
distribution of the various mesozoic deposits 
and their facies, the Banda Geosynchne had her 
continuation via Buton into the SE. arm of 



Celebes and Umbgrove distinguishes in his pub- 
lications a 'Timor-East Celebes Zone" with a 
different geological development than the area of 
the Sula Archipelago, Obi and southern Irian. 

This arc of islands is characterized by various 
remarkable phenomena such as the strong loop 
in the row of islands; the tertiary and recent up- 
lift, so that reef-limestones now occur at some 
hundreds to a thousand meter above sea level; 
their strong negative gravity anomalies; the non- 
volcanic character in contrast with the volcanic 
character of the visible part of the inner arc. On 
account of these phenomena the different authors 
all agree that the structural development of this 
arc of islands is still in progress and that it is an 
ideal place to study the various phenomena ac- 
companying tectonics. 




Fig. 6. The Banda Geosyncline after Umbgrove (1938). 



88 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



STRATIGRAPHY 



Crystalline schists form the basement of the 
mesozoic-tcrtiary sequence deposited in this 
geosynclinc. They are para-schists and gneisses 
mainly composed of mica schists, phyllitcs, quart- 
zitcs and amphibohtcs. This basement is exposed 
on Timor, Kisar, Letti, Moa, Scrmala, Dai, 
Babar, Tanimbar and Kai Islands, Tuir, Watubela 
Ccram, Burn, and Baton. Opinions about the 
possible age of these crystalline schists are rather 
varying. Wichmann (76) ascribed them an archaeic 
age; Hirschi (28) considered the schists of Portu- 
gese Timor as prc carboniferous, and Brouwer 
mentions the possibility of a relatively young age 
for these schists. On the island of Ceram there 
exists apparently a gradual transition between 
the crystalline schists and the weakly metamor- 
phosed phyllites and these again arc overlain by 
the non-mctamorphic sediments of a graywacke 
scries. Germeraad (24) reports from Ccntral- 
Ccram the occurrence of Lovcenipora in the 
eastern continuation of the graywacke series so 
that the age of this series can be fixed as Upper 
Triassic. The graywacke scries contains frag- 
ments of schists while the sandstones of this 
scries are mainly composed of crystalline schist 
detritus. This, at least, points to a gap between 
the phyllites and the sediments of the Upper 
Triassic. Up to now such a hiatus could only be 
investigated in Central-Ceram, where Deninger 
( MJfound upper triassic graywackes in immediate 
contact upon the schists, while Rutten stated that 
the schists were unconformably overlain by upper 
triassic sediments. From this the conclusion 
might be drawn that the age of the crystalline 
schists in Ceram should be at least pre upper 
triassic. 

For Letti MolengraafT (33) has proved that 
there exists a gradual transition between the 
crystalline schists and the non-melamorphic 
fossiliferous, permian sediments. The occurrence 
of the genera Agathoceras, Para/egoceras and 
Propinacoceras point to a lower permian age for 
these sediments so that the crystalline schists of 
Letti should be considered Lower Permian or 
even older. 

In the western part of Timor there are, accord- 
ing to de Waard (71 ), at least ten localities North 
of the central depression where crystalline schists 
are exposed in characteristic, sharp ridged moun- 
tain areas, measuring 10 to 20 Km across, usually 
surrounded by soft sedimentary strata. The 
investigations revealed a predominance of basic, 
low-to medium-grade, regional metamorphic 
rocks in particular chlorite schists and amphibo- 



htes, and local occurrences of phyllites, mica- 
schists, gneisses and granulites. Detritus of this 
schist complex occurs in the lower permian Kek- 
neno series. The origin of the oldest structures in 
the area is doubtless closely associated with the 
formation of these metamorphic rocks, which 
developed during the regional metamorphic 
conditions of an orogemc cycle, preceding the 
pacific (mesozoic) and alpine (tertiary) erogenic 
cycles. Since a permian or pre-pcrmian age is 
tentatively assumed for the crystalline schists of 
Timor (Brouwer, 72), the variscian oiogeny may 
be considered as the older orogemc cycle, in which 
these structures were formed (de Waard, 71), 

Wherever developed these crystalline schists 
form the base for the younger, mesozoic sequence 
of sediments; in the southern part of the geosyn- 
cline (Letti and Timor) they have been formed 
during metamorphic processes in lower permian 
or prc permian time, from those in the northern 
part (Ceram) it can only be said that this process 
occurred in pre upper triassic time. 

Permian sediments are only known from Timor, 
Letti, Luang, Babar and the Tanimbar islands. 
On Timor they are represented by a great variety 
of sediments such as shales, sandstones, lime- 
stones, marls, tuffaceous marls and tufls rich in 
all kind of fossils which permit a definite age 
determination. On Letti the Permian is repre- 
sented by a series of fossiliferous graywackes and 
arkosic and quartzitic sandstones. The occur- 
rence of the ammonite genera: Agathoceras, 
Paralegoceras, and Propinoccras places at least 
a part of this series into the Lower Permian. On 
the other islands the Permian is represented by 
crinoid-limcstones containing brachiopods and 
bryozoa. The occurrence of permian deposits 
on these islands introduces the formation of the 
Banda Geosyncline (c.q. the regeneration of the 
area) which apparently started in the southern 
part of the area, close to the old nuclei of the 
Australian Continent. 

Lower and middle triassic sediments occur only 
in Timor (fig. 7). On all the other islands of the 
Timor-Buru arc the Mesozoic begins with the 
Upper Triassic, developed in 5 different facies of 
which the so-called "Flysch facies" of Timor is 
the most important one. According to Wanner 
a very important upper triassic transgression 
occurred in the area with the result that also the 
northern part of the Banda Geosyncline developed 
as a sedimentary basin bordering the "Sula Spur" 
in the South. 

A similar facies is also well developed in Ceram, 
where these neritic deposits reach thicknesses of 

89 



PROCEEDINGS OF THE NINTH PACIEIC SCIENCE CONGRESS 



'* & 

!>> 



Y 




CRETACEOUS 



^T,. 



Fig. 7 Mesozoic sedimentation in the Banda Geosyncline according to Umbgrove (1938). 



800-2000 m and arc indicated by Valk (67) as the 
"Graywacke Formation" (sandstones and con- 
glomerates, shales, limestone, radiolarite and 
chert). Fossils give this formation a norian age. In 
West Ceram the rocks of this "Graywacke Forma- 
tion" pass apparently gradually into the underlying 
phyllites. This would indicate a continuous 
sedimentation from the schists and phyllites till 
m the Mesozoic. On the other hand the occur- 
rence of schist detritus in the triassic conglom- 
erates points to an unconformity at the base of 
the triassic conglomerate (basal conglomerate). 
In connection with this, Rutten (45) considers 
it not inconceivable that in certain parts of Ceram 
or in adjacent areas, which are now covered by 
the sea a pre-triassic(= variscian) orogeny might 
have taken place, while in other parts of the island 
sedimentation has been continuous. 

Wanner (73), however, is of the opinion that 
the observed conformity is only an apparent one, 
caused by structural phenomena and that the 
Lower Triassic is missing while the Upper Tri- 
assic is transgressive. 

The upper triassic "Flysch Series" of Timor 
and the "Graywacke Formation" of Ceram 
should be considered as similar deposits only with 
slight differences in facies while according to van 
Bemmelen (1949) the "Graywacke Formation" 
is richer in clastic material and in this connection 
deposited closer to the land than the "Flysch 
Series". The formation of such an extensive 
and thick flysch-graywacke series can only be 
explained by accepting that the sedimentary basin 
was situated close to (an) uplifted land area (s). 

This facial similarity, in particular that of the 
flysch-graywacke series, enabled us to line out the 
original trend of the Banda Geosyncline. This 
outline becomes still better pronounced in Jur- 
assic time when, at a rather short distance from 

90 



each other, two different facies begin to develop; 
a southern facies characteristic for the islands 
of the Timor-Buru-Buton arc and a northern one 
characterizing the Sula Islands, Obi and the 
southern part of Irian (- Sula Spur), thus demon- 
strating clearly the continuation of the Banda 
Geosyncline into the SE arm of Celebes and not 
by way of the Sula Islands into the Banggai 
Archipelago. On most of the islands there occurs 
a continuous sequence from the Triassic into the 
Jurassic. The Lower Lias is missing on some of 
the islands (e.g. Ceram and Buru), but there re- 
mains the possibility that the absence of this 
formation on these islands is caused by lack of 
information and that sediments of this age might 
still be found after more detailed investigations. 

The Cretaceous is absent on most of the islands 
but according to Stolley (55) there has been a 
continuous sedimentation from the Jurassic into 
the Cretaceous. Also Brouwer reports the oc- 
currence of Lower Cretaceous from eastern 
Ceram. Possibly the Lower Cretaceous was also 
developed on the other islands so that the 
supposed gap between the Upper Jurassic and the 
Upper Cretaceous might disappear as soon as 
more detailed stratigraphic information from the 
islands is obtained. 

GRANITES 

Granites occur on Timor in the southern and 
on Manipa, Kellang and Ceram in the northern 
part of the Eastern Banda Geosyncline. The 
Amboina (- Ambon) granites should be men- 
tioned together with those from Ceram, but their 
position is more on the southern border or even 
outside the actual geosyncline of the outer Banda 
arc. 

From the foreland granites have been reported 
from the Banggai and Sula Islands, Obi and the 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Aru Islands; from the hinterland from Wetar, 
Alor and Flores in the South, and Ambon in the 
North. 

De Waard ( 71) reports from Timor the occur- 
rence of pebbles of medium grained granitic rocks 
from permian conglomerates and loose blocks 
of mylonized granite on the crystalline schists of 
the Nefanoe region. 3 CatacJastic granites east 
of Atapupu, have been reported by Brouwer 
(12). According to de Waard these granites were 
intrusive in schists of the Palelo series and of 
paleozoic (variscian) age. 

The age of the granites from Ceram and sur- 
rounding islands is still an unsolved problem, 
though Kuenen (35) is enclined to ascribe 
them a post triassic age, while van Bcmmelen 
(4) considered them as Middle Tertiary (fig. 2). 
Martin discovered on Leitimor (S, Ambon) 
peridotite, followed by granite and a younger 
formation of sandstones, limestones, shales and 
probably diabase. Verbeek confirmed this 
sequence but ranged the diabase alongside the 
ancient peridotite. Kuenen (35) encountered 
this series on Hitu (N. Ambon) where many 
dikes of diabase and some larger intrusive bodies 
cutting the strata prove that the diabase is 
younger than the sedimentary rocks. So if 
Verbeek is right in placing the diabase and peri- 
dotite together, this demonstrates the greater age 
of the sandstones in comparison with the perido- 
tite and granite. 

Microscopic examination of the sandstones 
showed that quartzites and micaschists supplied 
large parts of the material for the sandstones. 
Verbeek's chief argument for considering the 
granites older than the sandstones, is thus refuted. 
The possibility, however, remains that at the time 
of the deposition of the sandstone material the 
granites, intrusive in the deeper parts of the 
schists, where not yet exposed to denudation. 
On the other hand the absence of detritus in the 
sandstones, derived from the peridotite, is strong 
evidence in favour of the greater age of the sedi- 
mentary series. Brouwer and Rutten are there- 
fore of the opinion that these sedimentary rocks 
were formed from the weathering of ancient 
gneisses, micaschists, etc. and that the absence of 
contactphenomena is probably due to abnormal 
contacts between the plutonic rocks and the 
sedimentary series. In accordance with this their 
general conclusion is that the plutonic rocks are 



therefore probably younger than the triassic 
sediments and consequently of late mesozoic age. 

Verbeek compares, of course, the granites of 
Manipa, Kellang, and Ceram with those from 
Ambon and is of the opinion that they are old, 
at least Permian. Based on the same arguments 
as those from Ambon, Rutten was at first also 
of the opinion that the Ceram granites were older 
than the overlying triassic sandstones but 
considered them later also as post triassic. Valk 
(67), Germeraad (24) and van der Sluis (49) 
restudied the available literature and the collected 
rock specimen from Ceram and came again to 
the conclusion that the peridotite and gabbro are 
younger than Triassic and because the granite 
seams to be intrusive in these rocks it is of post- 
triassic age. 

Resuming we conclude that there are various 
arguments in favour of a post triassic age of the 
Ceram and Ambon granites but it should be born 
in mind that the coupling of the peridotite and 
diabase by Verbeek rests on slender arguments 
and that neither the other arguments are ab- 
solutely watertight (Kuenen 35, 60). Though Valk, 
Germeraad and van der Sluis accept also a post 
triassic age for the Ceram granites we should keep 
in mind that their conclusion is not based on new 
field evidence. There always remains the possi- 
bility that further iieldwork reveals a pre triassic 
( = variscian) age for these granites and that 
they are intrusive in the old crystalline basement. 
This is certainly a point worthy of further field 
investigations. On the other hand there also 
remains the possibility that, since most authors 
consider them as post triassic, the formation of 
them should be brought in connection with one 
of the phases of the tertiary orogeny like van 
Bemmelen (4) docs on his map showing granite 
occurrences in Indonesia (fig. 2). 

The granites in the foreland of the Banda 
Geosyncline include those on the islands of the 
Sula Spur and the Aru Islands. All these granites 
arc clearly intrusive in the old crystalline base- 
ment. The granite of the Aru Islands is often 
compared with a similar boss at Mabaduan on 
the Southcoast of New Guinea and granites in 
the Cape York Peninsula of northern Australia. 
That the southern part of New Guinea does, in 
fact, still belongs to the Australian Continent 
has been quite definitely proved by oil-well drill- 
ing. The question of whether these granite bosses 



3 During fieldinvestigations in 1957 a granite mass with an estimated area of 2 x 5 KM2 was found North of the Moetis 
Massif on the border between Indonesian Timor and the Portugese enclave of Oeikoesi. The granite is intrusive in 
the crystalline schists and strongly influenced by a younger (tertiary) orogeny. 

91 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



are of pre-cambrian, Caledonian or variscian, or 
later age (and subsequently peneplaned) is not 
clear. Stille (52) marks his variscian front passing 
in a south-easterly direction from the northern 
Moluccas and Aru Islands towards western 
Queensland and considers these granites as 
variscian. A similar age was ascribed to them by 
Kolbel (32) and Glaessner (25); Fairbridgc (77, 
18), however, supposes a pre-cambrian age as well 
for the Mabaduan as for the Aru granite. 

The granite on the islands of the Sula Spur, 
in the Dutch literature known as "Banggai 
granite", are characterized by red felspars and 
all are intrusive in the crystalline basement. 
Most authors ascribe them an upper paleozoic 
( = variscian) age (Vcrbeek 69; Brouwer 9 and JO; 
Rutten 45: v. Bemmelen 4; Klompe 30). 

A granite occurrence on Batjan, West of 
Halmahcra, is also considered as of upper paleo- 
zoic age (Rutten 45; v. Bemmelen 4). When we 
suppose that the Mabaduan and Aru granites are 
intruded in the eastern continuation of the same 
crystalline basement as that of the Sula Spur, 
and there are no reasons to deny this, and that 
the process of metamorphism of this basement 
occurred during the same orogenic cycle, than we 
come to the general conclusion that these features 
arc the result of a young paleozoic orogenic phase 
which was accompanied or followed by the for- 
mation of syntectonic granites. In that case it 
will be very likely that this phase forms part of 
the variscian orogenic cycle. 

Granites in the hinterland occur on the islands 
of Wctar, Alor and Flores in the South and possi- 
bly we also have to include the granites of Ambon 
in the North. Those of the southern islands are 
doubtless all of tertiary age. Van Bemmelen on 
his map (fig. 2) even makes a distinction between 
those of Flores, belonging to the Middle Tertiary 
and those of Alor and Wetar being still younger, 
representing some of the youngest granites in the 
world. It has been mentioned before that van 
Bemmelen also ascribes the Ambon (and Ccram) 
granites a tertiary age, however, it is safer to 
consider their age for the time being as uncertain. 
It is doubtless correct that those younger granites 
are related to the tertiary orogenesis and the 
possibility remains that also the granites of 
Ambon and Ccram were formed during this last 
cycle of diastrophism. Upper paleozoic and 
tertiary granites occur within the area of the 
Banda Geosyncline (fig. 2). The paleozoic 
granites appear in the crystalline basement in the 
centre of the geosyncline (Timor) and the foreland 
(Sula Spur, Aru Islands). The tertiary granites 

92 



occur on some islands (Flores, Alor and Wetar) 
in the hinterland of the outer Banda arc. 

The Ambon and Ceram granites, first con- 
sidered as of upper paleozoic age, later as post 
tnassic, might even be of tertiary age thus be- 
longing to the youngest orogenic cycle. With 
the possible exception of the Ambon and Ceram 
granites there appear no real mesozoic granites 
in the area from which we conclude that no pacific 
diastrophism took place and that the variscian 
and tertiary orogenic cycles arc responsible for 
the metamorphism of the crystalline basement 
and the structural configuration of the present 
island arcs. A difference in age of the various 
granite occurrences in Indonesia characterizes 
the structural difference between the western and 
eastern parts of the Archipelago. In the western 
part mesozoic granites are prevalent and con- 
sequently the pacific ( mesozoic) orogeny should 
be considered as the main cycle of diastrophism 
in this western section. In the eastern part 
granites of this age are absent and those recorded 
are of paleozoic and tertiary age and therefore 
variscian and alpine cycles of diastrophism are 
responsible for the structural disturbances in the 
eastern section of the Archipelago. 

STRUCTURE 

A metamorphic series of para-gneisses and 
-schists below the permian and mesozoic strata, 
the unconformable position of sediments of 
various ages upon this crystalline basement, the 
occurrence of schist-detritus in triassic conglom- 
erates and sandstones, and the development of 
a thick triassic flysch-graywacke series from which 
the clastic material can be considered as the 
denudation products of an existing mountain 
system, have lead several authors to the conclu- 
sion that the metamorphism of these pre permian 
sediments was caused by a young paleozoic 
orogenic phase in this part of the Indonesian 
Archipelago. This orogeny was also required to 
develop a certain amount of relief in the earth's 
crust in order to supply the huge amounts of 
clastic material building up the upper triassic 
flysch and graywackc series. It is reasonable to 
suppose that this young paleozoic phase formed 
pan of the variscian orogenic cycle. 

There are no indications for angular uncon- 
formaties in the sequence of mesozoic strata; 
disconformities between the Triassic and Jur- 
assic and the Jurassic and Cretaceous have been 
reported but further detailed investigations might 
still reduce the number of these disconformities. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



These gaps in the mesozoic sequence and the 
variation in fades, particularly well developed in 
Timor, can be explained by submerging and 
emerging movements of the bottom of the geo- 
syncline. As a result not only variations in facies 
occur, but it is also possible that certain parts of 
the sequence were never deposited or were later 
eliminated by denudation. 

Perhaps with the exception of the central part 
of Ceram, where according to Germeraad (24) the 
Upper Cretaceous passes gradually into the 
Eocene, a late cretaceous folding (post Scnonian 
and pre Tertiary) has dislocated the various 
mesozoic deposits. This laramic erogenic phase 
should in this area be considered as a forerunner 
of the tertiary orogenesis, responsible for the 
structural pattern of this arc of islands. 

In general it is accepted that one of the typical 
structural features of this island arc are the over- 
thrust structures which have been studied on 
Timor and Ccram and which show thrusting 
features resp. in southern and northern directions. 
Based on recent research in Timor by D. de Waard 
(71 ) this author became convinced that Timor 
shows as well in a morphological as in a struc- 
tural sense considerable differences with other 
orogenic areas. There hardly exists any simila- 
rity between the structure of Timor and that of 
other tertiary sheet-mountain systems of the 
alpine type, though "alpmo-type" structures 
seem to predominate the tectonics of Timor. 
De Waard reports the following structural dif- 
ferences : 

1. a virgation of the folds in a certain direction, 
which can be seen in nearly all alpino-type 
mountain systems, seems to be absent in 
Timor. 

2. the Timor nappes are largely built up of soft, 
incompetent clayey and marly sediments. 

3. masses of hard competent rocks, such as 
irregular complexes of crystalline schists 
and Fatu-limestoncs, are irregularly dis- 
persed in the soft, incompetent beds. 

4. the position of Timor in a zone of negative 
anomaly which possibly is related to the 
special character of the structure. 

According to these differences the structure of 
Timor has her own characteristics and de Waard 
proposes to replace for Timor the expression 
"alpino-type structures" by 'Timor-type struc- 
tures". Though a certain succession of the 
various thrust series in Timor has been established 
by detailed surveying, it is, according to de Waard, 
difficult if not entirely impossible to fit these local 



detailed sections into the ideal general sections 
as constructed by Molengraaff and Brouwer. 
He concludes with the words that "the tectonics 
of Timor give the impression to be rather chaotic 
and can best be explained by gravity tectonics". 
Germeraad (24) illustrates the occurrence of 
important overthrusts in Central and East Ceram 
in a series of sections showing how a flysch nappe 
has been thrusted over various stratigraphic 
units and over the foreland in the North. He 
emphasizes, however, the fact that these sections 
should only be considered as a preliminary con- 
ception and that gravity tectonics in the triassic 
sediments might very well explain the irregular 
base of the sheet. More detailed research on 
Ceram and other islands of the arc might reveal 
similar chaotic structures as those described from 
Timor. 

CONCLUSIONS 

The geological and structural history of Timor 
illustrates very well the development of, at least, 
the southern part of the Banda Geosynclmc. 
According to de Waard this hislon "includes two 
periods of orogenic activity, the first possibly in 
young palaezoic limes and the second largely of 
tertiary age. Between these major structural 
occurrences has been a long period of relative 
rest with tectonic events of lesser importance and 
geosynclinal sedimentation of Timor's over- 
thrust scries since the lower Permian and through 
most of the Mesozoic". The geological history 
may be summarized as follows de Waard, (71 ): 

1. Sedimentation of argillaceous and calcar- 
eous rocks in probably geosynclinal condi- 
tions; subsequent subsidence. 

2. Early orogenic movements initiating the 
orogenic cycle; early orogenic or pre tectonic 
intrusion of basic igneous rocks. 

3. Low to medium grade regional metamor- 
phism; for at least the latter part of the time 
a synkincmalic recrystallization i c. con- 
temperancous with: 

4. The main tectonic phase of the variscian ( ?) 
orogeny; syntectonic development of foli- 
ation, mineral parallelism, folded structures 
and microfolds. Formation of syn-oro- 
genic granites (Klompe). 

5. Upheavel and denudation, possibly since 
pre-permian times, since minerals and rock 
fragments of crystalline schists have been 
found in Kekneno sediments of pcrmian 
and triassic age (de Roever 43); the end of 
the orogenic cycle. 

93 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



6. Sedimentation in geosynclinal environment 
since Lower Permian of various kinds of 
sediments of the different overthrust series 
to be. Regeneration of part of the quasi- 
consolidated variscian area (Klompe). 

7. Early orogenic movements of lesser impor- 
tance, initiating the alpine orogenic cycle, 
possibly the beginning of overthrusting 
movements and origin of zones of weakness 
in the schist basement; early orogenic in- 
trusion of ophiolites, including gabbride 
and diabasic rocks, in and near the crys- 
talline schists. 

8. Pretectonic phases, including the laramide 
phase, apparent from the unconformity 
between the mesozoic Palelo series and the 
Eocene in the sedimentary cover of the 
schist complex and the savian (?) phase, 
according to the disconformity between the 
Eocene and the Lower-Miocene. 

9. The main tectonic (styrian?) phase of the 
alpine orogeny in late miocene times; 
intense folding and overthrusting of tectonic 
units initiated in earlier phases; displacement 
of blocks of crystalline schists to exotic 
overlhrust masses in permian and mesozoic 
sediments, main origin of ruptural and 
cataclastic structures, and of border dis- 
tortions of pre-existing structures in the 
massifs. 

10. Sedimentation since pliocene times, post- 
tectonic fold-and fault-movements of lesser 
importance (de Waard 71). 

Based on these conclusions the pre-tertiary 
stratigraphic and structural history of the eastern 
part of the Banda Geosyncline can be outlined 
as follows: 

TERTIARY Beginning of the tertiary orogenic 
cycle with a moderate laramic phase 
(= last phase pacific orogeny) with ter- 
tiary phases at the end of the palaeogene 
(savian) and a main phase in late miocene 
time (styrian). 

CRETACEOUS Uninterrupted sedimentation 
from the Jurassic into the Cretaceous. 
On Buru and Ceram in-and extrusion of 
alkali rocks. Intrusions of ophiolites in 
the deeper parts of the geosyncline. 

JURASSIC Continuous sedimentation from 
the Triassic into the Jurassic. In Buru 
in- and extrusions of porphyrites, dia- 
bases and their tuffs. Intrusions of ophio- 
lites in the deeper parts of the geosyncline. 

94 



UPPER -TRIASSIC On Timor developed in 
5 different facies, on the other islands 
mainly developed as a flysch-and graywacke 
formation. 

MIDDLE and LOWER TRIASSIC Sedimen- 
tation only in Timor, Cephalopod facies. 

PERMIAN Sedimentation in Timor, Letti, 
Babar, and Selu (Tanimbar Isl.). The 
other islands formed at that time appa- 
rently a landmass. In Timor sedimen- 
tation accompanied by intrusions and 
extrusions of a trachy-basaltic nature, 
indicating that the real geosynclinal stage 
had not yet started. In Ceram intrusions 
of dacites and andesites, now occurring 
as dykes in the crystalline schists. 



Unconformity 



PRE-PERMIAN Metamorphism of a paleozoic 
sequence of sediments into a series of 
para-gneisses and-schists, possibly caused 
by a phase of the variscian orogeny, thus 
forming the crystalline basement for 
a new geosynclinal series. Synorogenic 
granites. Deposition of a series of argil- 
laceous and calcareous sediments. 

THE BANDA SEA AREA, 

A LANDMASS IN LATE PALEOZOIC 

AND EARLY MESOZOIC TIMES? 

This question forms since Verbeek's Report on 
the Moluccas (69) one of the most actual problems 
of the geology of the eastern part of the Indo- 
nesian Archipelago. Verbeek's own opinion is 
"that the deep basins and seas in the Moluccas, 
the Banda Sea included, are not the remainders 
of an old deep-sea, but that they have been formed 
by submergence of old landmasses in old-miocene 
time, yet mainly, during, or at the end of the 
Young-Miocene". 

Paleogeographically there seems to be sufficient 
evidence for repeated land connections across the 
Moluccan region, reaching back into the Paleo- 
zoic. This paleozoic continent, called "Aequi- 
noctia" after Abendanon (1), seems to have 
stretched from Tasmania to Celebes. Its break- 
up began, according to the same author, in car- 
boniferous time, though it is only in the Permian 
and Triassic that we encounter geosynclinal 
facies. 

A "Sino-Australian Continent", postulated for 
Jurassic times by Neumayer (41 ) is very im- 
probable since more became known from the 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



distribution of marine Jurassic deposits in the 
Moluccas. Umbgrove (63) also considered the 
probability of a late mesozoic landbridge here, 
though perhaps only developed as island "step- 
ping-stones" in places, for the floral differences 
alone between the mesozoic of Cathaysia and 
eastern Australia do not appear to favour a con- 
tinuous connection. From the topographic point 
of view, Kuenen (34) has demonstrated that it is 
difficult to draw a hard and fast line between 
Australia and the Indonesian Archipelago. The 
Timor trough does not seem to posses the charac- 
teristics of an ancient structural "seam". 

In the following some facts will be discussed in 
order to contribute some information to the 
problem about the existence of a late paleozoic 
and early mesozoic landmass in the present Banda 
Sea area. 

The rather thick and voluminous upper triassic 
ilysch and graywacke scries on nearly all the is- 
lands of the outer Banda arc have doubtless been 
deposited close to an extensive land area. Zwier- 
zycki (78) is of the opinion that this land area 
was located in the present Banda Sea, and Smit 
Sibinga (50) is of the same opinion. With the 
exception of a few papers on the geology of Ccram 
and Timor no advances of recent geological 
fieldwork in these islands have been published 
since the appearance of Zwierzycki's, Smit 
Sibinga's and Umbgrove's papers, so that only 
a re-examination of the existing literature forms 
the base of our speculations. 

Zwierzycki (78) mainly bases his conclusion 
on the distribution of the Triassic in the area: 
"the Lower and Middle Triassic being only 
developed in Timor while all other triassic local- 
ities belong to the Upper Triassic. Only in the 
Timor area the sea remained unchanged and an 
uninterrupted permian jurassic sedimentation 
took place. All other localities show the influence 
of an extensive upper triassic transgression. 
Close to the island of Timor we have to look for 
a shelf area which possibly separated a southern 
deepsea basin from a northern shallow sea area, 
or litoral zone". His general conclusion is that 
there existed in Lower-and Middle-Triassic a 
landmass North of Timor which became sub- 
merged during or after the upper triassic trans- 
gression. 

Smit Sibinga (50) subdivides the sediments in 
the Banda Geosyncline in the following three 
zones : 

a. a zone of litoral sediments, deposited in the 
immediate neighbourhood of the old shore- 
line, 



b. a geosynclinal zone of shallow-water sedi- 
ments, containing deposits of coal, oil, 
and asphalt, and 

c. an exterior zone of bathyal to abyssal sedi- 
ments. 

According to this author we find in Timor the 
facies of litoral sediments (Fatu facies and the 
Halobia shelf facies) in the NNW. part and the 
outer zone of bathyal and abyssal sediments 
(Cephalopod facies) in the central part of the 
island. In agreement with this position Smit 
Sibinga concludes to the possible occurrence of 
a landmass in the area North of Timor in upper 
triassic time. The distribution of the upper 
triassic fauna in Ceram indicates also that there 
must have been a landmass at that time South of 
Ceram so that the Timor-Banda Geosyncline 
surrounded a landmass, now occupied by the 
Banda Sea. 

Umbgrove (63) has dointed out that the present 
distribution of the various triassic facies should 
not be considered as the normal distribution 
shortly after their deposition but that it is the 
result of thrusting movements during the tertiary 
orogeny so that from this present situation no 
conclusions should be drawn about the possible 
course of a triassic coastline. In order to get 
near this problem the original distribution of 
facies in the area should be studied and investi- 
gated properly. The occurrence of areas of 
denudation on the inner side of the Timor-Ceram 
arc in triassic and Jurassic time, is closely related 
to pre tertiary folding and vertical movements in 
the area. Umbgrove concludes to the following 
two possibilities: either folding and subsequent 
denudation at the end of the Triassic (early cim- 
merian) or in the Lower Cretaceous (late ciminer- 
ian). In the first case denudation products could 
be supplied to the Banda Geosyncline in jurassic 
time in the second case, however, this was possible 
neither in triassic, nor in Jurassic time. Accord- 
ing to Umbgrove (63) we cannot make it accept- 
able that in triassic time denudation products 
were supplied to the Banda Geosyncline from a 
former landmass in the Banda Sea and conse- 
quently he is of the opinion that there existed in 
early mesozoic time a vast area of denudation 
along the northern, northeastern and southeast- 
ern borders of the Banda Geosyncline which 
comprised at least northern Australia, New 
Guinea, Obi and the Sula Islands, and probably 
also the Banggai Archipelago. His opinion is 
based upon the lacking of marine triassic sedi- 
ments in these islands and the occurrence of an 
unconformity in the Triassic of Misool. 

95 



PROCEEDINGS OF THE NINTH PACIEIC SCIENCE CONGRESS 



On these islands, however, marine Upper 
Jurassic is developed and in connection with that 
it is impossible that these islands represented in 
upper Jurassic time a landarea supplying material 
to the Banda Geosyncline. According to Umb- 
grove the only possibility remains in northern 
Australia, where no marine Jurassic deposits are 
known and were possibly never deposited. He 
emphasizes the possibility that in West and 
Central Borneo folding took place towards the 
close of the Triassic (early Cimmerian) so that 
this area might have acted as a supply area for 
the Banda Geosyncline. 

Summarizing we conclude that according to 
Zwierzycki and Smit Sibinga there must have 
been an upper triassic land mass in the present 
Banda Sea area but that Umbgrove is of the 
opinion that the area of denudation should not 
be looked for in the present Banda Sea but in the 
northern, northeastern and southeastern border- 
regions of the geosyncline, while in Jurassic time 
only Australia and possibly West and Central 
Borneo have acted as suppliers to the Timor- 
Ceram zone. 

It has been mentioned before that the present 
distribution of fades in the Timor-Ccram arc is 
no longer in accordance with the original sedi- 
mentation but that the present situation is the 
result of tertiary erogenic movements (over- 
thrusting, or gravitational tectonics). In case it 
could be proved that e.g. on Ccram the sediments 
become coarser further to the South, than the 
conclusion could be drawn that at least the clastic 
material should have come from a land-area in the 
South. In connection with this it is of importance 
to study the structural features of these islands. 
It is in general understood that thrusting move- 
ments in the Timor-Ccram arc have been directed 
towards the North, East, and South. Assuming 
that these various overthrust movements are the 
result of a simple lateral compression in the earth's 
crust it becomes clear that the highest thrust- 
masses have been transported furthest and that 
their original accomodation was inside the Banda 
arc. In case it could be proved that these highest 
thrustmasses, as far as facies concerns, must have 
originated from places closest to the area of 
denudation, it would become clear that the main 
area of denudation should also be looked for at 
the inner side of the Banda arc. 

From Ceram we know that the basement is 
formed by crystalline schists followed by the 
Graywacke Series. This series forms a kind of 
transition zone between the phyllites in the South 
and the Upper Triassic in the North. Germeraad 

96 



(24) discovered Lovcenipora in samples of the 
eastern continuation of the Graywacke Series. 
This fossil has also been found in the upper tri- 
assic Flysch Formation from which we might 
conclude that the Graywacke and Flysch forma- 
tions are of the same age. According to van der 
Sluis (49) the two formations only have a dif- 
ference in facies and van Bcmmelen (4) is of the 
opinion that the Graywacke Series contains more 
clastic material and has thus been deposited 
closer to the land than the Flysch. According to 
the present distribution of these two formations 
we find that in West Ceram the Graywacke Series 
occurs more frequently in the southern part of 
the island than the Flysch, consequently the 
southern sediments of West Ceram have been 
deposited closer to a land area than the northern 
ones. In connection with this the following 
remarks by Rutten (44, p 38) are of importance: 
"Close to Atiahu, on the Southcoast, there are 
conglomerates in the Triassic mainly built up of 
pebbles of crystalline schists. In these conglom- 
erates occur boulders up to '> m^ in size of a 
coralline triassic limestone. These conglomerates 
have been formed close to the coast where, during 
their deposition, triassic reef-limestones were 
destroyed b> the surf and included in the conglom- 
erate. 1 his process clearly proves the deposi- 
tion of landwaste close to the present southcoast 
of the island and it is possibly true that the further 
North we go the sediments were deposited further 
offshore". 

For the structure of West Ceram Valk (67 ) is 
of the opinion that a normal contact between the 
Graywacke Series and the Upper Triassic Flysch 
was never observed. Everywhere we find the 
Graywacke Series thrusted in northern direction 
against and over the Flysch, which means that 
the more clastic deposits were originally deposited 
further to the South, which means closer to a 
land -area. 

It is impossible to make a similar reconstruc- 
tion for the central part of Ceram, the structural 
position of the Graywacke Series in comparison 
to the upper triassic Flysch is not clear so that no 
dependable conclusions about the original dis- 
tribution of facies can be drawn. Beside that, it 
is the opinion of Germeraad that gravitational 
tectonics complicated the structural picture con- 
siderably and made it impossible to reconstruct in 
a similar simple way the original facies distribution. 
Stratigraphy and structure of eastern Ceram are 
not yet cleared so that it is also impossible to 
reconstruct for this part of the island the original 
distribution of the triassic facies. 



VOLUMt 12 



GEOLOGY AND GEOPHYSICS 



As far as Timor concerns we have seen already 
that, according to Smit Sibinga, the litoral Fatu 
and Flysch facies and the Halobia facies were 
originally bordered in the South by a zone of 
bathyal and abyssal sediments (Cephalopod 
facies), which indicate the occurrence of a land- 
mass North of the geosynclinal basin, but in 
general the structure is here too complicated to 
allow a reconstruction of the original distribution 
of the triassic facies. Recent field investigations 
in Timor have convinced de Waard (71 ) that 
gravitational tectonics plays an important role 
in explaining the structural features of Timor, 
which makes it, of course, all the more difficult, 
if not entirely impossible to unravel this compli- 
cated structure and also to reconstruct the original 
distribution of the various types of sediments in 
this part of the Banda Geosyncline. 

Little is known about the structural features 
of the other islands of the outer Banda arc so 
that it is not possible to use the geology of these 
islands to reconstruct a general distribution of 
facies over the whole area. 

Weber (in Umbgrovc 63) makes the following 
interesting remark in consideration to the occur- 
rence of an old landmass in the Banda Sea area: 
k4 On account of the absence of index-fossils the 
stratigraphic position of certain finegrained white 
rocks, closely connected with radiolaria-hornfels, 
occurring on Tanimbar and Ceram has not yet 
been cleared. Lithologically these rocks show 
great similarity with quartzsandstone containing 
Mciciophaliies* Bclcmnopsis and Aucella occurring 
on Misool and belonging to the Lower Malm 
(Oxford). This sandstone is very pure and con- 
tains only little mica and clay. Because the two 
main occurrences (Tanimbar-Ceram) of this sand- 
stone are at distances of 400-600 Km in N-S 
direction from each other, it is logic to suppose 
that a landmass of equal lithologic (and possibly 
also stratigraphic) character must have occupied 
the present Banda Sea in Jurassic time. Coarser 
grained quartzsandstones, possibly also of Jur- 
assic age, have been encountered at the entrance 
of the Bay of Kolonedale and show a great 
similarity to rocks from the small island Tobea, 
North of Moena". From this remark we con- 
clude that the landmass was emerging in triassic 
time and still existed as such in the Upper Jurassic, 
submerging must have taken place in post Jur- 
assic time. 

This also demonstrates clearly the great im- 
portance of sediment-petrographic data for such 
problems, but also that an increase of our elemen- 
tary knowledge of the pre tertiary history of the 



Greater and Lesser Sunda Islands will be of the 
greatest importance for obtaining an insight into 
the mesozoic history of the Banda Sea area. 

Though a study of the original distribution of 
the various types of sediments in triassic time in 
West Ceram contributes only little to the solution 
of the problem on the occurrence of an old land- 
mass in the Banda Sea area and to that of epciro- 
genic movements in this area at the end of the 
Triassic, I believe that there arc sufficient argu- 
ments to accept that the thick and voluminous 
Graywacke Series and upper triassic Flysch 
sediments have originated from an emerging 
landmass situated on the inner side of the outer 
Banda arc. 

However, much more information on the 
stratigraphy and structure, type and direction of 
the movements of the Banda Geosyncline should 
be obtained before this problem can be solved 
satisfactory. 

The supposition of the occurrence of a late- 
paleozoic early mesozoic landmass docs not 
include that all clastic sediments have derived 
from it. With Umbgrove the author is of the 
opinion that in the Upper Triassic also clastic 
products from the Sula Islands, Obi, West New 
Guinea and northern Australia have contributed 
considerably to the gradual filling-up of the sub- 
siding Banda Geosyncline. 

The old landmass was peneplamed in early 
mcsozoic time, submerged since than along faults 
and now forms the floor of a deepsea basin. This 
is completely in agreement with Kuenen's sup- 
position (34) that the Banda Basin belongs to a 
group of basins caused by faulting. The gravi- 
metric map of this area shows that the Banda Sea 
area has a positive anomaly which possibly means 
that submergence and faulting are the possibi- 
lities for re-establishing the broken isostatic 
equilibrium. Nothing definite can be said about the 
time of submerging but this definitely happened 
in post Jurassic time. According to Kuenen 
(34) the development of the present strong 
relief of the East Indies was accomplished in 
miocene and post miocene time. Direct evidence, 
as to the age of formation of the present deep 
depression is not available. Nevertheless there 
are two arguments in favour of a comparatively 
recent development. In the first place, Umbgrove 
points out, that there occur since the Mesozoic 
no stratigraphic indications of deeper facies in 
any division of the geological timescale, in the 
entire archipelago. In the second place, Molen- 
graaff drew attention to the fact that the miocene 
folds of Timor are cut off obliquely by the present 

97 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



coast, which is directly fronted by the deep basins. 
These basins thus appear as the counterparts of 
the rising geanticlines to which they run parallel. 
From these two facts it becomes evident that the 
present deepsea relief of the Indonesian Archi- 
pelago is a characteristic feature that must have 
originated during the recent geological past 
(Umbgrove 64), Kuenen (34) arrived at an ana- 
logous opinion about the origin of these deepsea 
basins and exhaustively argues that the deepsea 
basins originated recently by the subsidence of 
"continental" (sialic) areas. 

THE SAHUL SHELF AREA 

While in a geographical sence Australia is an 
isolated landmass, inspection of a bathymetric 
map shows that it stands upon the same sub- 
merged shelf or platform with New Guinea and 



Tasmania, and that the combined continental 
mass is separate and distinct from the continent 
of Asia. About the mutual relations of these two 
continents during geological time much difference 
of opinion exists, but there are certain grounds 
on which former land-connections between them 
have been claimed. There are geologists who 
consider that the present contiguity of SE. Asia 
and Australia has only been attained since meso- 
zoic time. There can, however, be no doubt of 
the continuity of Australia with Tasmania and 
New Guinea in tertiary time, but apart from this 
there are evidences of extensions of the continent, 
in both East and West beyond present limits, in 
the geological past. 

In the West the fact that folded geological 
formations ranging in age from Pre-Cambrian 
to Tertiary, deposited in the Westralian Geosyn- 
cline are truncated by the Western Australian 



LES S R SU N D 



Ashmort 

INDIAN ,,; 



GEOTECTONIC PATTERNS OF 

NORTHERN AUSTRALIA 

AND THE SAHUL SHELF 



. ! CAMBRIAN 

rnary ; C ' (mar 



M~~ M"; ME5070IC [ N *N"NULLACINE 

--M..J cKtntilJ i.. 1 ?..- cimbntn) 

p" " V"! PERMIAN r>V^V." OLDER 

; (mamly merin*) !.->>^! PRE- CAMBRIAN 

.....,' includes om* L^. 

Devonian, etc metamorohics ] 



r BA S/N r 




Fig. 8. Geotectonic Sketchmap of Northwestern Australia and the Sahul Shelf after Fairbridge (1952). 



98 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



coastline is in itself an indication of former ex- 
tension into the Indian Ocean (David 75, Vol. f, 
p. 686). 

The westernmost part of the northern con- 
nection between Australia and New Guinea, the 
Sahul Shelf, forms in its position between Aus- 
tralia and Asia, facing the Indonesian Archi- 
pelago, a critical zone. "Matters of fundamental 
importance to Australian-Asiatic geotectonics 
and palaegeography are bound up in this 
region". "Nothing is known directly of the 
geology of the Sahul Shelf since no continental 
rocks are exposed on it. So we must look for 
analogies on the adjacent mainland". 

With these words Fairbridge respectively closes 
and opens his description of the structure and 
geological relationship of the Sahul Shelf area 
in one of his many publications on this area 
(Fairbridge 79). It is particularly this author 
which made geologists familiar with this part of 
the continental shelf North of Australia and the 
following summary on the structure and geolog- 
ical relationships of this shelf area is based on 
Fairbridge's publications (18,19,20). According 
to this author (19) the northern Australian con- 
tinental shelves are divisable conveniently into 
three; the Rowley Shelf (West of Cape Leveque); 
the Sahul Shelf (sensu stricto) ; and the Arafura 
Shelf (East of Cape van Diemen, but not includ- 
ing the Gulf of Carpentaria, which is contiguous 
to it) (fig. 8). Most Dutch geologists (e.g. 
Brouwer 8; Zwierzycki 79; Kuenen 34), referring 
in their publications to the Sahul Shelf, take it 
to cover the entire northern border of Australia, 
extending 2,000 miles from North- West Cape 
and Exmouth Gulf in the West to West New 
Guinea and Torres Strait in the East, including 
even the shelf-sea, extending West of the "Birds- 
head" of New Guinea to Misool. Fairbridge, 
however, restricts this name to the central part 
only, an area 500 miles long and 200 miles across. 

This shelf area is, particularly by Dutch geo- 
logists, often considered as the counterpart of 
the Sunda Shelf which extends on the Asiatic 
side of the Indonesian Archipelago. This com- 
parison might be a sound one from a geomor- 
phological point of view but from this synopsis 
it will become clear that the structural features 
and geology are certainly not the same. On the 
Arafura Shelf the Aru Islands represent the only 
continental shelf island so far out. Most authors 
now agree that they belong structurally to the 
Australian-New Guinea continental block (Gre- 
gory 26; Fairbridge 18). Verbeek (69, p. 175) 
described the Arun Islands as a low miocene- 



pliocene limestone plateau, entirely horizontal, 
but much jointed and dismembered into blocks 
and recementcd by a cover of young coral lime- 
stone. The mio-pliocene beds are very gently 
folded (Tayama 59). Coarse grains of terrigenous 
minerals in the otherwise calcareous sediments 
(quartx, mica, felspar) indicate that the basement 
is not far off, and in one small locality near Sia 
(Serani), Tissot van Patot (62) found granite 
(according to van Bemmelen, 4) which Zwierzy- 
cki compared with a similar boss at Mabaduan 
on the Southcoast of New Guinea. As has been 
stated already Fairbridge accepts a pre-cambrian 
age for both granite occurrences but several geo- 
logists, including the author, ascribe them an 
upper-paleozoic age. 

As far as the quaternary history of the islands 
concerns, there are several significant features. 
Firstly the essentially "Australian" character of 
the Aru Fauna and flora; secondly, there are no 
emerged pleistocene coral-reefs on Aru (Kuenen 
33), and thirdly there are the peculiar "sungeis", 
which are deep channels crossing the islands 
from side to side. Wallace (1857) suggested that 
they were remnants of drawned stream beds; 
others, however, (Verbeek 63; Brouwer 7; van 
Straclen 56) have concluded that these initial 
lines of weakness were due to jointing or perhaps 
even faulting. From this quaternary material 
the conclusion can be drawn that the Aru Islands 
represent the summit of a broad ridge. This 
inconspicuous rise, called Merauke Rise, extends 
from the Aru Islands to Prins Frederik Hendrik 
Island (fig. 9) and from there along the Oriomo 
axis of southern New Guinea via Torres Strait to 
the York Peninsula of Australia. On this 
Merauke Rise, representing the margin of the 
continental shield of Australia some isolated 
exposures of the pre-tertiary basement complex 
are found, covered by a thin veneer of tertiary 
and quaternary sediments (granite basement on 
Aru Islands and Mabaduan in South New Gui- 
nea). This rise which was slowly arched up from 
the Arafura Shelf towards the close of the Pleis- 
tocene might also be considered as a relict still 
showing the original trend of an older mountain 
system possibly of variscian age in conformity 
with the age of the occurring granites. Also the 
initial lines of weakness on the Aru Islands, pos- 
sibly caused by faulting, are showing a similar 
E-W trend. It is apparent that the Aru Islands 
belong structurally to Australia, although they 
differ from the major units of northern Australia 
in view of their age. 

The surface of the Sahul Shelf is far from even. 
It lacks the smooth contours of the Sunda Shelf. 

99 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




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ARNHEM 

I I I I I I I I I I I 




Fig. 9.- Bathymetric chart of Arafura Depression showing "Merauke Rise" and "sungeiV of the Aru Islands (Fair- 
bridge 1951). 



On the contrary, the Sahul Shelf is divided into 
many flat-topped plateaus and terraces, in places 
with submarine "cuestas" sloping down the 
shallow basins or depressions (fig. 8). 

Since the Aru Islands form the only exception 
of continental rocks exposed on the shelf area we 
have to look for analogies on the mainland in 
order to obtain some information about its geo- 
logy and structure. One of the most important 
papers on the geology of the Australian Continent 
in recent years is a study of the tectonic trends by 
Hills (27), who assayed a first attempt at a struc- 
ture pattern for the older pre-cambrian rocks 
(fig. 10). Fairbridge (17) extended Hills' tectonic 
pattern to cover the whole Australian-New Gui- 

100 



nea-New Zealand area in a broad way (fig. 11). 
He adopted Stille's idea of Eo-, Paleo-, Meso-, 
and Neo-Australia, but modified the outline 
sketches prepared by Kolbel, 32; Stille, 52; and 
Glaessner 25 considerably. "Structurally the 
northern part of Australia consists of a number 
of major tectonic blocks, which are marginal to 
the great pre-cambrian shield and show alter- 
nating positive and negative tendencies to rise or 
sink during post archaean times. Only the early 
pre Cambrian rocks of this region are extensively 
folded, metamorphosed, and intruded by granites. 
All subsequent sediments are flat-lying or gently 
folded, and hardly at all metamorphosed. The 
folding is restricted to narrow, active belts asso- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 10. The pre-Cambrian nuclei of Australia after E.S. Hills (1945). 



elated with the margins of the blocks, which are 
generally bounded by major normal-faults, mono- 
clines or broad warps. Post Archaean diastro- 
phism is thus mainly epeirogenic, with restricted 
fragmentation (taphrogeny) and fault-folding of 
Saxonian type" (Fairbridge 19, p. 14) 'These pre 
cambrian blocks arc marginally overlapped by 
a series of younger basins ("paraliagcosynclines" 
in the terminology of Marshall Kay 1951 ; "paralic 
basins*' of Tercier). These represent broad down- 
warps of the continent, being now filled up to 
20,000 feet of sediments ranging in age from 
the paleozoic to the Quaternary. Locally these 
sediments are heavily faulted and gently folded 
(Germanotype tectonics), but nowhere are they 



affected by major orogenic compression" (Fair- 
bridge 20). 

From West to East the following structural 
units of the mainland can be distinguished (figs. 10 
and 11): 

a. Pilbara Block. 

b. Canning or Desert Basin. 

c. North Kimberley Block. 

d. East Kimberley and Western Rivers Basins. 

e. Arnheim Block. 

f. Carpentaria Depression. 

g. Carpentaria Block. 

Only some of Fairbridge's (19, 20) general con- 
clusions in regard to the geology of these various 

101 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



GEOTECTONIC 

EVOLUTION 
OF 

AUSTRALIA 



Continental Shelf of Australia 
Neo-Austrolion f.Alpme) fold directions 
Mfsozoic * Tcrtioru Front" i 



Permian A Carboniferous trends 

Older Poleoioic Front * 

Of der Po/eozoic /rends & 13 lands" 

Edge of Pre-Combnon 
Pre- Cambrian trends(por1 lu offer 
Hit/ 1/946) 




Fig. 11. Eo-, Palco-, Meso-, and Neo- Australia according to Fairbridge (1950). 



structural units will be mentioned here. The 
adjacent continent of the North Australian Shelf 
area consists of a number of topographically, 
structurally, and stratigraphically well marked 
blocks and basins, which can be traced into the 
shelf area, were depressions and rises are arranged 
opposite the basins and blocks of the continent so 
that the histories of the continental shelves are 
directly related to the tectonic history of the 
adjacent continent. The deep-sea basins in turn 
seem to lie opposite the broad shelves and the 
continental basins, while the deep-sea ridges lie 
in the same trends as the pre Cambrian structural 
"grain" of the mainland. From this it may be 
concluded that the features of the deep-sea floor 
are intimately related to those of the continent, 
102 



. a point recently re-emphasized by Cloos (14) and 
Lees (38). 

Stratigraphic and paleogeographic data indi- 
cate that much of northern Australia and its 
continental shelf region have been continental 
since Archaean times. Paleogeographic and 
faunistic connections suggest that this continental 
area (either as land or shelf) formerly extended 
far to the Northwest including the northern 
Moluccas in mesozoic times and possibly even 
reaching to Celebes in the Late Paleozoic. The 
geosynclinal evolution of the Timor- Banda arc 
set in with the Permian and Trias, apparently 
encroaching on the old continent. From Timor 
south-westwards, however, there is nothing to 
suggest that the present limit of the continental 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



shelf (and slope) has not approximated to the examination of the adjoining Timor Trough and 

margin of the continent for very long periods in a few places extended it into the shelf. This 

(Fairbridge 79, p. 29). was enough to show that on the Sahul Shelf there 

In connection with his gravimetric research of is generally a regional isostatic anomaly of less 

the East Indies, Vening Meinesz made also an than plus 50 milligals, comparable to that of the 




+ 100- *150 milhgal !'''! 50 - + 100 milhgal | | +50 milhgal 

-50 milhgal V/%%\ -100 - -50 milhgal B888888 -250 - -100 milhgal 

Fig. 12. Isogam Map of the Eastern Part of the Indonesian Archipelago (Scale 1 : 10,000,000). 



103 



PROCEEDINGS OF THE NINTH PACIMC SCIENCE CONGRESS 



Sunda Shelf (fig. 12). The Timor Trough ano- 
malies are quite characteristic of continental 
margins (Vening Meinesz 68). While the bathyme- 
tric curve slopes down from the shelf edge to the 
floor of the Timor Trough, the gravity anomaly 
curve maintains a high course (mostly on the 
positive side) for a considerable distance beyond 
the shelf edge before it plunges to the negative. 
Actually it reaches its lowest at a point roughly 
coinciding with the Southcoast of Timor (over 
minus 100 milligals), after which it rises steeply 
again to a notable positive anomaly in the interior 
of the inner Banda arc. It gives the impression 
that the continental structure and material of the 
Sahul Shelf continue out beyond the actual edge 
of the shelf. (Fairbridge 79, p. 20). 

In reviewing the evidence of the belt of negative 
anomalies coincident with the belt of the outer 
Banda arc and its "foredeep", the Timor Trough, 
Kuenen (34, p. 62) writes: 'The Australian Con- 
tinent influences the direction of the line of nega- 
tive anomalies, but hardly in character or inten- 
sity. There is nothing in the gravity field to 
indicate either that the Australian block was 
forced up against the arcs, or that the outer Banda 
arc was originally a regular curve and was 
subsequently moulded up against the already 
existing slope of the continent". 

Fairbridge ends his paper on the structure and 
geological relationship of the Sahul Shelf with 
the following general conclusion (79, p. 24): 
"There seems to be evidence for concluding that 
the present geomorphologic relationship of the 
outer Banda arc to the Timor-Aru Troughs and 
the Sahul-Arafura shelves is a relatively recent 
(i.e. late tertiary and quaternary) phenomenon. 
The relationship between the mesozoic-tertiary 
mobile zone and the semi-rigid foreland appear 
to follow out a normal transition in the northern 
Moluccas, though are obscured in the Timor 
Trough-Sahul Shelf sector. 

In the Banda arcs there is no sign of the borders 
of the ancient Australian Continent, which may 
have extended much further North and West 
than it does today". 

VARISCIAN OROGENY IN AUSTRALIA 
AND ADJACENT AREAS 

Sometimes a comparison is drawn between 
India and Australia. India, dominated in the 
North by the huge arc of the Himalayas and 
fronted by the depression of the Indo-Gangetic 
plain, beyond which stretches the old pre cam- 
brian mass of Peninsula India. This last has its 

104 



counterpart in the present Australian Continent 
and the first in the mountains of New Guinea 
and the island-festoon which stretches from it to 
New Zealand. The intervening depression is 
represented by the deeply foundered Tasman and 
Coral Seas, the shallow Arafura Shelf and the 
lowlands of southern New Guinea. 

This comparison, however, is not very satis- 
factory because it has now become clear that the 
Australian Continent was built out to the East 
and Northeast by repeated deposition followed by 
folding and uplift of the gcosynclinal sediments, 
around a pre Cambrian nucleus. A corresponding 
phenomenon has not been reported from the 
northern border of the pre cambrian mass of 
Peninsula India. 

A first attempt at a very broad tectonic classi- 
fication of Australia was made by E. Suess in 
his 4v Face of the Earth" (58), when indicating the 
successive belts of alpine folding in New Guinea 
New Hebrides Fiji- New Zealand, as the First, 
Second, and Third Australian arcs; the paleozoic 
folds of eastern Australia he indicated as Aus- 
tralian Cordillera, and recognized to the west of 
these a broad tableland, similar to the pre Cam- 
brian cores of other continents. 

In more recent time several authors have re- 
viewed the geotectonic evolution of Australia 
(David 75; Kolbel 32; Fairbridge 17 and Hills 
27), and in the following the conceptions of Kol- 
bel (32) and Fairbridge (77) on the occurrence of 
variscian orogeny in eastern Australia will be 
discussed in connection with a possible extension 
of this zone to the Northwest. 

In the general recapitulation of Volume 7/8 of 
the "Geotektonische Forschungen" dealing with 
tfc Die tektonische Entwicklung dcr pazifischen 
Randgebicte II", Stille (52, p. 276) remarks that 
..there occur in the western border region of the 
Pacific only two areas from where important 
variscian erogenic activity is reported. These 
areas are eastern Australia and Peninsular Indo- 
China. In eastern Australia the bretonic, middle 
and upper variscian phases have been active. 
It is remarkable that in Australia the variscian 
folds do not show advancements towards the 
continent against which the virgations are gener- 
ally directed but, on the contrary, show a contin- 
uous retreat in the direction of the Pacific. The 
results of the variscian orogeny must have reached 
till New Caledonia and New Zealand and possibly 
occupied the whole section of Neo-Australia (fig. 
13). On account of the conformity in the permian- 
triassic series of New Caledonia the folding should 



GEOLOGY AND GEOPHYSICS 



60 




130 



160* L 



16OW I 



Urconiments 
Caledonic zone 




Vanscic zone 



Cimmeric zone 




Austrian zone 



zone 



Tertiary zone 



Fig. 13. Orogenetic zones in the SW. Pacific after Stille (1945). 



have taken place in middle variscian time and 
the same can be expected for New Zealand. 

To the Northwest this folding, inclusive the 
intrusive activity, extended till in New Guinea 
and further West till in the Sula Spur (Klompe 
30). In the remaining part of the Indonesian 
Archipelago variscian folding seems to be absent 
because the dominating magmatic activity was in 
upper paleozoic time exclusively of the initial type. 

In this same volume of the "Geotektonische 
Forschungen" Kolbel (32, p. 187) discusses in the 
chapter on the geotectonic evolution of Australia 
the following occurrences of variscian phases of 
orogeny in the Eastern part of Australia (fig. 14): 
The results of the bretonic phase (Ilia) are found 
in the southeastern part of New South Wales 
and possibly also the foldings in the Hodgkinson, 
Palmer, and Pascoe drainage areas of Queensland 
and in eastern Victoria are of the same age. 

In New England (northeast New South Wales) 
and South of Townsville (eastern Queensland) 



the Carboniferous and partly also the Permian, 
are stongly dislocated. A strong middle variscian 
phase (I lib) is reported from the western part of 
New England, while considerable upper variscian 
movements (IIIc) are known from eastern Queens- 
land and New England from where also contem- 
poraneous intrusions and ore deposits are known. 
In his short review on Australian geotectonics, 
Fairbridge (1950), though adopting the Stille idea 
of subdividing Australia in Eo-, Paleo-, Meso-, 
and Neo- Australia (fig. 11), modified considerably 
the outline sketch prepared by Kolbel (fig. 14). 
Comparing both conceptions we see that Fair- 
bridge restricted his Meso-Australian belt to a 
much narrower zone near the eastern seaborder of 
Australia, bounded in the West by a tectonic line 
running from the Bowen Basin in Queensland to the 
Hunter Valley (S. of New England). In the North 
the part of Kolbels Meso-Australia of the Cape 
York Peninsula is included in resp. Paleo- and Eo- 
Australia, while in the South the border between 

105 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Fig. 14. Eo-, Paleo, and Meso- Australia according to Kolbel (1945) Ilia bretonic, lllb middle variscic, IHc young 
variscic. 



Meso- and Paleo-Australia is drawn much further 
to the West, while here also the eastern part of 
Tasmania is included in Meso-Australia. The 
rocks in this belt were folded and intruded by 
granites during the various phases of the variscian 
revolution. Parts of this zone are covered by 
younger deposits, but these are nowhere intensely 
folded. Younger faulting has produced mono- 
clinal and associated folds, but these are not 
truly orogenic in character. The eastern limits of 
this belt are, for the most part, buried beneath 
the Tasman and Coral Seas and New Zealand 

106 



geologists are of the opinion that it extends as far 
East as the deep submarine ridge West of New 
Caledonia. A small amount of late cretaceous 
folding in the extreme East of Queensland might 
be mentioned but from the general character of 
post paleozoic earth-movements it seems that 
these folds are simply associated with the block- 
faulting of Meso-Australia. 

The differences of opinion between Kolbel and 
Fairbridge on the age of diastrophism in the 
Cape York Peninsula will be discussed more in 
detail as they are of particular interest in regard 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



to our conception on the continuation of the belt 
of variscian orogeny in northwestern direction 
toward the Indonesian Archipelago. Charac- 
terizing the part of Eo-Australia in "Problems of 
Australian Geotectonics", Fairbridge (17) men- 
tions that Eo-Australia not only covers the whole 
western part of Australia but reaches even as far 
as northern Queensland. In this respect his con- 
ception differs considerably from the earlier 
representation by Kolbel (32), \Vhich depicts a 
paleo- and meso-australian zone in northern 
Queensland. The only argument, mentioned by 
Fairbridge, to support his idea is the occurrence 
of pre cambrian metamorphics and granites in 
northern Queensland with a possible extension 
of these to Torres Strait, Mabaduan on the South- 
east of New Guinea and the Aru Islands. 

Kolbels conception is based on a careful examin- 
ation of the existing literature. According to 
him the so-called "Drummond Revolution" 
(Reid 42) belongs at the earliest to the bretonic, 
possibly even to the middle variscian erogenic 
phase, dependent on the age ascribed to the 
Aneimites Series which can be compared with the 
lower carboniferous Kutting Series of New South 
Wales which possibly also includes the Upper 
Carboniferous. In the Drummond Mts. the 
Lower Carboniferous of the Upper Star Series 
with Lepidodcmdron vehheimianum is unconform- 
ably overlain by the permian Lower Bowen 
Series. 

In the Hodgkinson Palmer area the upper 
devonian Lower Star Series with Lepidodendron 
australe are conformably and very strongly folded 
together with the Gothlandian of Chillagoe 
(Bryan 13\ Reid 42). The various folds trend 
N. to NNW. and partly even NW. to WNW. 
At Mt. Mulligan, northeast of Chillagoe these 
highly dislocated layers are unconformably over- 
lain by the Permian. 

In the Pascoe River area, on the Cape York 
Peninsula, metamorphic schists are overlain by 
non-metamorphic, but folded beds with Lepido- 
dendron and Cordaites. Here, apparently, two 
diastrophic phases occurred, one before and one 
after the deposition of the younger carboniferous 
sequence. The age of the first phase is question- 
able, but that of the second one is definitely bre- 
tonic or middle variscian, like in the other sections 
of the same belt. Intrusions and ore deposits 
accompanying this orogenic phase are unknown 
but possibly the gold and tin deposits in the hin- 
terland of Cairns and Cooktown, the silver-lead 
occurrences and copper ores of Chillagoe, Her- 



berton and Clermont are connected with the 
"Drummond Revolution". 

Also David and Browne (75, p. 325) recognize 
the end of the Lower Carboniferous as an im- 
portant epoch (the great Kanimbla epoch) of 
orogeny and plutonic intrusion, being the greatest 
and most important in the history of the Tasman 
Geosyncline. According to these authors "the 
incidence of the movement appears to have ex- 
tended from Cape York to the South of Tasmania, 
a distance of more than 2,000 miles, and to have 
affected the whole of the zone of paralic sedimen- 
tation, together with some of the marine zone to 
a total width of about 600 miles. Not merely 
were the carboniferous strata folded but also the 
upper devonian, and in places middle and lower 
devonian beds as well. The total thickness of 
carboniferous and devonian strata subjected to 
folding was moderate, and over most of the area 
involved probably less than 10,000 feet. The 
resultant uplift in the orogenic belt was not 
necessarily very great, and indeed there is some 
reason for believing that a series of ridges or 
mountain ranges may have been formed with 
belts of scarcely folded and only slightly uplifted 
sediments between. Along the margins of dif- 
ferential uplift there was doubtless some readjust- 
ment by faulting. As a result of the orogeny the 
upper carboniferous geosyncline was severally 
contracted, and restricted to a relatively narrow 
coastal belt". 

This short survey shows that there are sufficient 
arguments in favour of Kolbels interpretation 
that the NE. part of Queensland has been strongly 
dislocated by various phases of a variscian orogenic 
cycle, which foldaxes trend in N. to NNW. 
(Hodgkinson-Palmer area), NW. to WNW. 
(Chillagoe area), and NNE. to NE. (Pascoe area) 
directions. In a paper on the "Geotectonic 
Position of New Guinea", Glaessner recognizes 
12 elementary units in the structure of the island 
of which the description of the southern stable 
area is particularly important to us (25, p. 858). 
"This area is characterized by shallow granitic 
basement, cropping out only near the southern- 
most point of the island, and disappearing north- 
ward under a thin cover of late tertiary sediments, 
mainly in limestone facies, and alluvium. It has 
long been recognized that the southern part of 
New Guinea belongs to the Australian Continent 
from which it is separated only by the shallow 
marine transgression of Torres Strait. Owing to 
this separation and the sedimentary cover it is 
impossible to recognize within the geologically 
"Australian" part of New Guinea distinctions 

107 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



between the tectonic elements of the adjacent 
part of Australia. Their distribution suggests, 
however, that part, if not all, of the stable area 
of southern New Guinea lies in the continuation 
of the folded geosynclinal zone of eastern Austra- 
lia rather than on the pre-cambrian Shield. It 
seems likely that folded paleozoic sediments, 
intruded by granites, continue in a northwesterly 
direction towards the folded ranges of western 
New Guinea, where silurian (?), devonian, and 
younger paleozoic sediments appear. There 
could still be room for an extension of the pre- 
cambrian Shield underneath the tertiary veneer 
in southwestern New Guinea. On the other 
hand, the Great Artesian Basin extends to the 
southern and eastern shores of the Gulf of Car- 
pentaria and over the western part of Cape York 
Peninsula. It is possible that the mesozoic strata 
of this basin reach New Guinea and that they 
mask there, as they do on the Australian main- 
land, the borderline between shield and gcosyn- 
cline". On I-airbridge's gcotcctonic sketchmap 
the southern part of New Guinea is included in 
Eo-Australia, forming part of the pre-cambrian 
Carpentaria Block. The main reason for not 
accepting a younger, variscian cycle of orogenesis 
for this stable part of New Guinea is that the 
trend of such a zone would be "quite contrary 
to the pre-cambrian "grain" of Arnheim Land 
and north Queensland" (Carpentaria Block, 
Hills 27; Fairbridge J8, 26}. In his geotectonic 
sketchmap (fig. 11), however, he sketches the 
"grain" of the northern part of the Carpentaria 
Block parallel to the strike of the continuation of 
a variscian zone passing through this area to the 
Sula Spur, as accepted by others (Stille 52; 
Klompe 30). 

Since more details about the structural features 
of the pre-cambrian continental blocks have been 
obtained it is now generally accepted that these 
blocks are composed of pre-cambrian consoli- 
dated nuclei, welded together by younger pre- 
cambrian and post-cambrian orogenies. They 
show the features of a huge "porphyroblastic 
gneiss", in which the porphyroblasts are repre- 
sented by the old nuclei and the surrounding, 
younger zones represent the matrix, smoothly 
surrounding these porphyroblasts. Good exam- 
ples of such structures can be observed in the 
African and Australian Shields and the Indian 
Peninsula, where the "grains" of the different 
nuclei and orogenic zones are often quite uncon- 
formable to each other. 

CONCLUSIONS 

A review of the pre tertiary strati graphic and 
108 



structural development of the Banda Geosyncline 
and the re-examination of the literature on the 
problem of the Banda Sea area have lead the 
author to the conception that there existed in late 
paleozoic early mesozoic time a landmass in the 
eastern part of the Indonesian Archipelago, oc- 
cupying at least the present Banda Sea area, the 
zone of the outer Banda arc and the area North 
of it, called the Sula Spur (Klompe 30). 

A process of regeneration of marginal parts of 
this land-area started in the South (Timor) in 
permian-lower triassic time and spread to the 
North (Ceram) with the result that a new geo- 
synclinal area, the so-called "Banda Geosyncline" 
was introduced in Indonesian geology. The 
various strata deposited in this geosyncline show 
no signs of participating in the pacific orogenesis, 
stratigraphic gaps and changes in facies are the 
result of movements of an epeirogenic character. 
This regenerated zone should be considered as 
transitional and of only semi-mobile character 
and should be distinguished as an "intermediate 
area" and evolves tectonically with intermediate 
type structures (Saxonian or Germanotype of 
Stille), but which do not reach the degree of 
mobility that results in granitization or plutonic 
injection. 

The influence of the tertiary orogeny on the 
Banda Geosyncline has produced intermediate 
type structures, assuming that the overthrust 
structures on Timor and Ccram are the result of 
gravitational tectogenesis in a descending basin. 
The chapters on the Sahul Shelf area and the 
occurrence of an important belt of variscian 
orogeny in eastern Australia and northern 
Queensland make it acceptable that the pre-cam- 
brian nuclei of the Australian Continent can be 
traced to the North and Northwest over certain 
distances of the Sahul and Arafura shelves, while 
the belt of variscian orogeny (Meso-Australia) 
" should be traced from northern Queensland 
(Cape York Peninsula) to southern New Guinea, 
Ceram, the Sula Spur, the Aru Islands and Timor, 
including the late paleozoic landmass in the 
Banda Sea area which also should be considered 
as the result of the variscian orogeny. 

THE STRUCTURAL CONTRAST BETWEEN 

WEST AND EAST INDONESIA 
A NEW STRUCTURAL SYNTHESIS 

The various conclusions reached in the first 
and the second part of this paper lead to the 
general and main statement that there is not only 
a great difference in a geomorphologic and faun- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



istic sense between the western and eastern part 
of the Indonesian Archipelago but that there 
also exists a great difference in structure, which, 
of course, contributes to explain the geomor- 
phological differences. 

The general conclusion drawn from this struc- 
tural review of the Indonesian Archipelago is, 
that the structure of the section West of Strait 
Makassar (the Sunda Shelf area) is mainly the 
result of different phases of the pacific orogeny 
setting out from the pre-cambrian and variscian 
consolidated mass of Indochina and surrounded 
by a fringe of tertiary orogenic structures. 

In the eastern section of the Archipelago the 
variscian orogeny resulted in the development of 
an extensive landarea Northwest of the Australian 
Continent. In late paleozoic-early mcsozoic time 
a process of regeneration started in the marginal 
zone of this land area leading to the formation of 
a so-called "intermediate area". Mesozoic cpei- 
rogenic and tertiary orogenic movements in this 
"intermediate area" and young tertiary-quater- 
nary epeirogenic movements in the whole eastern 
part of the Archipelago are mainly responsible 
for the present structural and bathymetric picture 
of this part of the Archipelago. According to this 
conception Strait Makassar forms a line of de- 
marcation of the first order and forms actually 
the boundary between Asia and Australia. 

In 1860 Wallace stated in his classical essay: 
"The western and eastern islands of the Archipe- 
lago belong to regions more distinct and con- 
trasted than any other of the great zoological 
divisions of the globe". The boundary line 
between both faunal realms, known as "Wallace 
line", has since been much criticized as well as 
defended and from this synopsis it becomes clear 
that the "Wallace line" is also according to geo- 
logic structure a very important boundary. 

In the following points some of the most strik- 
ing differences between the western and eastern 
part of the Indonesian Archipelago are given: 

1. In the western part there are no indications 
for a variscian orogeny while in the eastern 
part results of variscian orogeny have up to 
now been reported from the Sula Spur area, 
Ceram and Timor. 

2. Unconformities in the mesozoic sedimen- 
tary cycle have been met with in many 
localities of the Sunda Land area, while 
there has been an undisturbed mesozoic 
sedimentation in the Banda Geosyncline, 
only interrupted from time to time. 

3. The western part is characterized by a strong 
pacific orogeny while, with the exception of 



some cpeirogenetic movements, no mesozoic 
orogenic phases have been active in the 
eastern part of the Archipelago. 

4. Many occurrences of mesozoic granites 
have been reported from Sumatra and 
Borneo and some of the smaller islands, 
while in the eastern part of Indonesia only 
paleozoic and tertiary granites occur. 

5. The Sunda Land area shows a steady zonal 
growth in southwestern, southern and eastern 
direction; East Indonesia does not show any 
indications for such a regular growth, in the 
contrary, part of the quasi-consolidated varis- 
cian landmass participates in a process of 
regeneration and in consequence transfers 
part of this area into a zone suitable to 
renewed, in this case, tertiary orogenesis. 

6. In the Sunda Shelf area there are many high 
islands which rise steeply as nunataks from 
the floors of the shelf sea; the only islands 
out on the Sahul and Arafura shelves are 
the low Aru Islands, from which might be 
concluded that the erosive forces were pos- 
sibly longer active here than in the West. 

7. On the isogam map of Indonesia we see 
that the western part of the area shows a very 
steady positive gravity anomaly, while the 
eastern part shows a very great variation as 
well in positive as in negative anomalies. 

It is with great hesitation that the conclusions 
of this paper, resulting in the statement that there 
exists a great structural difference between the 
western and eastern part of the Indonesian Archi- 
pelago, will be used as a base for a new structural 
synthesis of this area. For this reason the accom- 
panying structural sketchmap (fig. 15) should 
only be considered as a preliminary effort to 
illustrate the authors ideas in a general way. 

In this preliminary geotectonic sketchmap the 
western part of the Indonesian Archipelago is 
shown as an outgrowth of the southeastern part 
of Asia. The map shows the various areas in- 
fluenced by paroxysmal diastrophism of resp. 
the variscian, Cimmerian, laramic and tertiary 
cycles and phases of orogeny, centred around the 
old pre Cambrian nucleus of Indochina. It shows 
how the main part of the Sunda Land area is 
mainly built up by the pacific orogeny, fringed in 
the West, South and East by a more or less con- 
tinuous zone of tertiary diastrophism. On this 
same map is shown that a considerable part of 
eastern Indonesia, embracing the southern part 
of New Guinea and its continuation in the Sula 
Spur, the areas of the Banda Geosyncline and 
the Banda Sea and parts of the Sahul and Arafura 

109 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PACIFIC 
.'OCEAN 



S^-l-v^ 




INDIAN 
OCEAN 



Fo Idmargms of 
Variscian folding 
Cimmerian folding 
Laramic folding 

ry x> of folding 

Volcanic 
Non volcanic ^^ 




Border* of: 

Eo Australia -- 

Paleo - Australia ^ 

Meso - Australia, *> ' 

Regenerated r of the *,* 

Banda Westrahan Geosynclme & 

Direction of movements *^ 



Fig. 15. Preliminary Sketchmap of the Geotectonic Evolution of Australasia according to Klompd (1957) 



110 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



shelves, were dislocated, but not consolidated, by 
the variscian orogeny. This part forms what 
Stille has called an "intermediate" or "quasi 
cratonic" area. Regeneration of marginal parts 
of this intermediate area has created the possib- 
ility for the formation of a geosynclinal ("parageo- 
synclinal") basin, the Banda Geosyncline. 
During the tertiary orogenesis the sequence of 
strata, deposited in this half circular troughshaped 
basin was deformed to what is presently known 
as the outer Banda arc. Various problems related 
to the geology and geophysics of the Indonesian 
Archipelago will be solved supposed this or any 
further modified structural picture of the Archi- 
pelago, based on this conception, is accepted as 
a working base. In the first place this conception 
gives a satisfactory explanation for the great 
contrast between the western and eastern parts 
of Indonesia of which the most striking points 
have been enumerated before. 

Most recent structural maps of Indonesia 
show a number of structural zones which are 
often traced over the entire Archipelago. In 
Westerveld's tectonic scheme of the East Indies 
(fig. 3) as well the Sunda as the Moluccas orogens 
are reproduced by belts from almost the northern 
end of Sumatra and the islands off the Westcoast 
till in the Philippines. The author is of the opinion 
that these two zones certainly have the value of 
showing some common characteristic features 
(such as e.g. volcanic and non-volcanic) but that 
they do not represent uninterrupted orogenic 
zones resulting from continuous geosynclines. 
The first tectonic schemes of the alpine orogene 
in the Mediterranean also tried to arrange the 
various mountainsystems into continuous belts 
(Suess 55; Termier 67; Kober 1912; Staub 55, 
54; Stille 57) but since the structure of these 
mountainsystems became better known it is now 
generally believed that it is not possible to trace 
a certain mountainsystem simply over the whole 
Mediterranean area (de Sitter 48). It is true 
that certain mountainsystems have some char- 
acteristics in common but one goes to far con- 
necting up all mountainsystems in the Mediter- 
ranean, based on the occurrence of certain rock- 
types, like e.g. Kober does with his "metamor- 
phides". Only two cases in which a simple 
continuation cannot be accepted will be men- 
tioned here and both can be explained very well 
in accordance with this conception. In the first 
place the interruption of the zone of negative 
anomaly South of Sumba has never been 
explained in a satisfactory way, this conception 
not only gives an explanation for this interrup- 
tion but might possibly also give an acceptable 



explanation for what Umbgrove has called the 
"Sumba Problem". 

In the second place the volcanic zone of the 
inner Banda arc is on Westerveld's scheme con- 
nected up with the volcanic zone of the Lesser 
Sunda Islands on one side and with the partly 
extinct and partly still active volcanic zone of 
resp. western and northern Celebes on the other 
side. According to the author, however, this 
volcanic inner Banda arc cannot be compared 
with the volcanic zone of the Lesser Sunda 
Islands and Celebes and should certainly not be 
connected with these parts into one continuous 
zone. Our preliminary map shows that there 
might exist some relation between the volcanic 
zone of western and northern Celebes and the 
one from the Lesser Sunda Islands. 

Kuenen (35) in his paper on the geology of the 
Islands Ambon and Haroekoe writes in con- 
nection with this (pp. 44 and 45): "The inner 
Banda arc is generally drawn along the volcanic 
islands of the Banda-Sea as far as Banda and 
thence curving sharply to the Schilpad-and 
Lucipara-Islands and Gn. Api North of Wetar. 
The depth-chart of the Snellius (fig. 5), however, 
shows that between Manoek and Banda the 
ridge of the inner Banda arc is not clearly con- 
tinuous and that there is definitely no connection 
with the ridge bearing the Schilpad- and Lucipara- 
Islands. Gn. Api lies quite apart and morpholog- 
ically it forms no part of the arc. Even the north- 
ern Siboga-ridge is separated from the Banda 
shoal. From a morphological point of view the 
continuation of the Banda arc is formed by the 
Oeliasers, although the connection is not a distinct 
one. It might be urged that the absence of active 
volcanoes on the Oeliasers and Ambon is a reason 
for disregarding this connection and for termi- 
nating the inner arc at Banda. But the volcanic- 
ity of Wetar and neighbouring islands also at 
a point where the arcs are close together has 
been extinct for a long period also, probably 
quite as long as that of the Oeliasers, yet nobody 
doubts that Wetar forms part of the arc. 
Although the conception of a volcanic inner 
Banda-arc becomes increasingly vague when 
applied further East of Java than the island 
Panter, it is my opinion that, if extended to in- 
clude the Banda Group, there is no reasonable 
argument for not including the Oeliasers, Ambon, 
the submarine cone in Strait Manipa and Ambe- 
lau". "The Outer Banda arc is traceable to 
Sanana (southernmost of the Sula Islands) as a 
unit but not further although of course the invi- 
sible tectonic structures continue. In the same 
manner the inner arc ends as a distinguishable 

111 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



unit where it merges into the outer arc in Boeroe". 
From these paragraphs the conclusion can be 
drawn that Kuenen favours the idea that the 
inner volcanic Banda arc begins in Strait Manipa 
and ends on Wetar and conform this point of 
view the inner Banda arc is represented in this 
preliminary tectonic scheme. 

With regard to the position of Sumba, Umb- 
grove (65, p. 189) remarks: "Obviously the island 
does not belong to the volcanic inner arc. 
Neither in stratigraphy nor in structural history 
is it intimately related to the islands of the outer 
arc, such as Timor and Roti" and consequently 
Westerveld does not include this island cither in 
the Sunda, nor in the Moluccas orogcn. Umb- 
grove (66, p. 42) adds to that: "In our opinion 
Sumba is the exceptional example of a sort of 
terrain that elsewhere subsided so as to form the 
bottom of one of the series of deepsea furrows 
between the outer and inner arcs". 

In fact very little is known about the geology 
of Sumba and what is known is not exactly in 
harmony with each other. In a rather recent 
report on the Geology of West-and Central- 
Sumba, Laufer and KraefT (36) describe the pre 
tertiary rocks as a slate formation, probably some 
thousand of meters in thickness and subjected 
to strong orogeny. The only fossils are poorly 
preserved plant remains. When compared with 
European sections, the rocks appear to be paleo- 
zoic rather than mesozoic. The orogeny can only 
be dated as being pre tertiary, as the slates are 
covered transgressively by eocene sediments, 
which are only slightly dislocated (tilted). Mag- 
matic intrusions probably accompanied this 
orogeny, which account for the quartz-gabbros 
and granogabbros and the great granodiorite 
massif of Tanadaro. 

In "The Geology of Indonesia" van Bemmelen 
(4, table 106) summarizes the pre tertiary geology 
of Sumba as follows: 



Geological 
Period. 



Pre Tertiary 

(at least 
partly 
Jurassic). 



Formations and 
fossils. 

Partly marine 
flysch facies, 
partly non- ma- 
rine flood plain 
or delta deposits, 
with volcanic 
constituents (In- 
oceramus and an 
ammonite). 



Diastrophism 

and igneous 

activity. 

Strong folding, 
followed by up- 
lift and igneous 
intrusions and 
extrusions. 

(Volcanic acti- 
vity on a slow- 
ly subsiding 
basement. 



112 



Whereas Laufer indicates in his report that the 
strongly folded slate formation is sooner paleo- 
zoic than mesozoic, is van Bemmelen's opinion 
that it is at least partly Jurassic. In the first case 
the results of the variscian orogeny would have 
reached in the South as far West as the island of 
Sumba and the Tanadaro granodiorite would be of 
late paleozoic age. In the second case, however, 
it has to be accepted that the influence of the late 
mesozoic, possibly laramic, folding phase has 
reached further East than Central-Java and in that 
case the Tanadaro granodiorite would be of late 
mesozoic age. Because our knowledge about the 
geology of Sumba is still in a preliminary stage, 
the structural position of the island has been left 
an open question in our structural scheme. 

It is not only from this part, but also from 
other areas of the Indonesian Archipelago that 
more information should be gathered and that 
various geophysical and geological phenomena 
should be studied more in detail before a more 
reliable scheme based on this conception can be 
produced. One of the first problems that ought 
to be studied is the exact status of Strait Makas- 
sar, which in this geotectonic synthesis forms 
such an important boundary. 



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GEOLOGY AND GEOPHYSICS 



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VOLUME 12 GEOLOGY AND GEOPHYSICS 

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115 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



MESOZOIC OROGENIES IN THE ISLAND OF SUMATRA AND 

THEIR ORE-DEPOSITS 

GEORGE A. DE NEVE 

Department of Geology , Andalas University, Bukittingi, Central Sumatra, 

(Abstract) 



The geological structures of the Indonesian 
Archipelago are due to the fact that it is located 
at the -intersection of two global mountain 
systems. The structures are governed by folding 
processes which took place throughout the ages 
at this very weak spot in the earth's crust. 
Although tectonic forces were never completely 
at rest, two main periods of movements bringing 
ore-deposits of economic importance in the 
island of Sumatra can be distinguished. 

The mainly cassiterite, gold, wolframite and 



bauxite deposits in Indonesia belong to the oldest 
Mesozoic tectonic unit in the Western part of the 
Archipelago which is of Upper Jurassic age. (It is 
called the Malayan orogen by Westerveld.) 

Evidences of a Cretaceous tectonic unit in the 
island of Sumatra are the pyromctasomatic iron- 
ore and gold-silver deposits of the so-called Suma- 
tran orogen. 

An outline is given concerning the develop- 
ment of both orogenies in relation to their mineral 
wealth brought in Sumatra. 



116 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



NOTES ON MESOZOIC OROGENY IN WEST BORNEO 



N. S. HAILE 
Geological Survey Department, British Territories in Borneo^ Saiawak 



The Mesozoic formations known in West 
Borneo (West Sarawak and West Kalimantan) 
are of Triassic, Upper Jurassic, and Lower and 
Upper Cretaceous age. The Mesozoic geological 
history of the area is summarized in table 1 . 

LATE PERMIAN OR 
EARLY TRIASSIC FOLDING 

Granite at many places in West Borneo is 
believed to have been cmplaced in late Permian 
or early Triassic times. At Tenting Bedil in the 
Strap Valley of West Sarawak the age has been 
estimated by the zircon method (Roe, 6). Granite, 
forming the Jagoi and Kisam Ranges (southwest 
of Bau) and the small headlands of Tanjong Batu 
and Tanjong Pandan (North of Lundu) is similar 
in composition and is believed to be of the same 
age as that forming Tenting Bedil (Wilford, o\ 
76), Many granite batholiths in W r est Kali- 
mantan (especially in the Sehwancr Mountains 



and the southwest) are attributed by Zeylmans 
van Emmichoven to the same period (9, 137). 

It seems probable that the emplacement of the 
granite was accompanied by fairly strong folding 
movements, since the Upper Triassic beds appa- 
rently lie unconformably on rocks of Permian or 
Carboniferous age. Zeylmans van Emmichoven 
attributes formation of phyllite and marble in 
the Termocarboniferous' of West Kalimantan 
to orogenesis in the early Triassie period (9, 
192-193). 

TRIASSIC SEDIMENTS 

Triassic sediments and volcanic rocks occur in 
the Sadong Valley of West Sarawak, whence they 
extend West into the Sarawak River Valley, and 
South into the Sekajan and Landak Valleys of 
West Kalimantan. Fossil molluscs in shales 
indicate an Upper Triassic age (Krekeler, 4 and 
5; Haile, 2, 21-22; Wilford, , 43). The rocks are 



Table 1. 
Mesozoic geological history in West Borneo. 



Sedimentation 



System 



Southern area 
(Sarawak, Sadong, 
Sekajan, Landak, 
and Seberuang Val- 
leys) 



Northern area 
(Lupar, Saribas and 
upper Kapuas Val- 
leys) 



Orogeny 

and 
epeirogeny 



Igneous activity 



Cretaceous 



Jurassic 



Triassic 



Upper 


Limestone, marl, 
shale, tuff, sandstone, 
conglomerate and 
radiolarian chert in 
shelf facies 


Shale and graywacke, 
with tuff and radio- 
larian chert in south- 
west in geosyncli- 
nal facies 


Slow subsidence in 
southern area: rapid 
subsidence in north- 
ern area 


Tuff and tuffite de- 
posited in south- 
ern area ; basic 
lavas and tuffs ex- 
truded, and dole- 
rite sheets intrud- 
ed, in northern area 


Lower 


Possibly some sedi- 
mentation, including 
formation of lime- 
stone 


Slow subsidence in 
southern area 




Upper 


unknown 






Lower 


UNCONFORMITY; EROSION 


Folding? 




Upper 


Shale, sandstone, 
conglomerate, and 
coal in estuarinc 
and neritic facies 


unknown 




Extrusion of acid 
lavas and tuffs 


Lower 


UNCONFORMITY; EROSION 


Folding? 


Intrusion of gran- 
ite? 



117 



PROCEEDINGS OI I HE NINTH PACIFIC SCIENCE CONGRESS 



shale, feldspathic sandstone, conglomerate, rare 
coal seams, and, in places, interbedded acid lavas 
and tuffs. 

POSSIBLE LATE TRIASS1C OR 
EARLY JURASSIC FOLDING 

The Upper Triassic rocks are overlain by 
sediments of Jurassic and Cretaceous age. The 
Triassic, Jurassic, and Cretaceous sediments are 
all moderately folded, and Wilford records 
(8, 90) that in many places the strike of the 
Triassic sediments coincides with that of nearby 
Jurassic and Cretaceous sediments. The junction 
between the Jurassic and Triassic has not been 
observed ;Wilford suggests that it is unconformable 
and that folding movements probably occurred 
at the beginning of the Jurassic period (8, 93). 

UPPER JURASSIC TO 
UPPER CRETACEOUS SEDIMENTS 

The late Mesozoic sediments in West Borneo 



occur in different facies in two separate areas. 
The southern area comprises the Sarawak, 
Sadong, Sekajan, and Landak Valleys, and the 
Seberuang Valley in the middle Kapuas area 
(see map); the northern area comprises the 
Lupar and Saribas Valleys, and the far head- 
waters of the Kapuas. Sediments of Upper 
Jurassic to Cretaceous age the southern area 
are predominantly calcareous, and occur in shelf 
facies; Upper Cretaceous rocks in the northern 
area are shale, slate, phyllite, graywacke, and, 
in places, radiolarian chert and rare limestone. 

SOUTHERN AREA 

The Jurassic and Cretaceous sediments of the 
Sarawak and Sadong Valleys comprise of massive 
limestone, which occurs as lenses as much as 
1 ,000 feet thick or more, shale, marl, sandstone, 
graywacke, conglomerate, radiolarian chert and 
tuff. They are considered on palaeontological 
evidence to range from Upper Jurassic to Upper 



Outcrop of the Jurassic and 
1 Vest Borneo 




SHELF -FACIES 
(Cretaceous and 
Jurassic ) 



h ^) GEOSYNCLINAL FACIES ( Upper Cretaceous ) 
{ f4f\ (a ) Slaty sub -facies ( central ) 
( a ) ( b ) f b ^ Cn * r ty sub-focies ( marginal ) 



.. s 
SARAWAK QtOtOGICAl OFFICE MAP i2t BY 

118 



4 * Internotionol boundary 

F. BORNEO BY FW ROE. 1857 



LOCATION MAP 




VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Table 2. 
Relationship of the facies of the Jurassic and Cretaceous in West Borneo. 



Shelf Facies 
(Southern Area) 



Geosynclinal Facies 
(Northern Area) 



UPPER 
CRETACEOUS 



LOWER 
CRETACEOUS 



UPPER 
JURASSIC 



Sekajan and Sarawak 
Valleys 


Seberuang Valley 


Slaty sub-facies 
(central) 


Cherty Sub-facies 
(marginal) 


Thin limestone beds, 
marl, and radiolarian 
chert 
Calcareous tuffite, gray- 
wacke, grey and green 
shale 


Sandstone, arkose, 
limestone, radiolarian 
tuff, tuffaceous ag- 
glomerate and con- 
glomarate 


Hard shale, slate, phyl- 
lite, and graywacke 


Shale, graywacke, tuf- 
fite, radiolarian chert 
and rare limestone 


Massive limestone, 
shale, sandstone, and 
conglomerate 


Marl, shale, feldspa- 
thic sandstone 




Limestone ? 


Massive limestone, 
chert, and marl. 
Basal sandstone 









Cretaceous (Cenomanian); no evidence of post- 
Cenomanian members has been found. Wilford 
concluded (#, 66) that the Jurassic and Cretaceous 
sediments of the Sarawak and Sadong Valleys 
were deposited in a shallow sea partly overlying 
a shelf. 

The Jurassic and Cretaceous sediments of the 
Landak and Sekajan Valleys in Kalimantan are 
contiguous with and similar to those of the 
Sarawak and Sadong Valleys, although more 
littoral conditions occur to the South. They 
have been described by Zeylmans van Emmie- 
hoven, from information provided by F.X. 
Krekeler (Zeylmans van Emmichoven, P, 98-101): 

' ... in the middle reaches of the Sekajan, the 
Cretaceous was laid down in a narrow, shallow 
basin between the Permocarboniferous massifs 
(composed largely of acid plutonic rocks) of 
the Kembajan Mountains and the Landak 
Border Mountains. Along the fringes of these 
massifs the Cretaceous consists of coarse to 
fine-grained polymict feldspathic sandstones, 
which alternate with coarse clastic conglom- 
erates . . . and lenses of Orb itolina- bearing 
limestones. East and north of Kampong 
Balai Karangan (on the Sekajan River) and 
along the Rubin River to the Sadong (Kajan 
tributary), the Cretaceous transgresses over the 
Permo-carboniferous Triassic with an iden- 
tical basal series. These coarse clastic, locally 
calcareous, sediments, in a clear beach facies, 
give way, in the direction of the Sekajan River, 
partly by intercalation, to finer clastic marly 
deposits, which were laid down further away 
from the coast . . .' 



Jurassic rocks are known in West Kalimantan 
only from small areas in the Landak and Sambas 
Valleys (Zeylmans van Emmichoven, P, 82-84). 

The Seberuang Cretaceous, in the Middle 
Kapuas, has been mapped in some detail by 
Zeylmans van Emmichoven P, 85-97). The sedi- 
ments are about 10,000 feet thick, and almost the 
whole of the Cretaceous system is believed to be 
represented (Valanginian to Senonian), The 
sediments are marl, shale, sandy limestone, con- 
glomerate, sandstone, and arkose, with acid to 
intermediate tuffs and tuffaceous agglomerate. 

NORTHERN AREA 

Cretaceous sediments occupy about 1,760 
square miles in the Lupar and Saribas Valleys, 
occurring in a belt about 34 miles wide and 
extending east-southeast into the Kapuas head- 
waters. They have been described in detail by 
the writer (Haile, 3, 33-49). No elements older 
than Cenomanian have been found, with the 
exception of a fragment of limestone in a volcanic 
conglomerate, which contains a foraminifer of 
probable Lower Cretaceous age. The sediments 
occur in two sub-facies of contrasting lithology: 
a cherty subfacies in the south forms a belt 8^ 
miles wide, of shale and sandstone, and rare lime- 
stone, with associated altered basalt, dolerite, 
gabbro, tuff, tuffite, and radiolarian chert; and a 
slaty sub-facies in the north consisting of hard 
shale, slate, phyllite, and graywacke. The rocks 
are intensely folded, probably isoclinally, and the 
thickness cannot be measured; it is certainly 
great, probably more than 30,000 feet. 

119 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



CONDITIONS OF DEPOSITION OF THE JURASSIC AND 
CRETACEOUS 

The Jurassic and Cretaceous in the southern 
area appear to have been laid down on an unsta- 
ble shelf. The conditions of deposition of the 
Seberuang Cretaceous are considered by Zeyl- 
mans van Emmichoven to have been preponder- 
antly littoral-neritic with beach and lagoon depos- 
its, and occasionally to have approached a neritic 
character; the Jurassic and Cretaceous in the far 
West, as we have seen, is neritic in the North, 
with beach deposits in tne South. 

The Cretaceous in the northern area is a typical 
geosynclinal (flysch) series. The slaty sub-facies 
was probably laid down in the central part of a 
geosyncline, and the cherty sub-facies along the 
margin. These facies differences are related to 
the regional structure of west Borneo. The 
older, mostly pre-Jurassic, rocks, forming the 
western part of Borneo, appear to have formed 
a stable block since Jurassic times. This concept 
of a 'continental core' or 'continental triangle' 
has been developed by van Bemmelen (7, 19; 
pi. 13, iig. 138), who visualizes the core as being 
formed by Crystalline Schists (probably pre- 
Carboniferous) invaded and largely replaced by 
granite of Permo-Triassic, Jurassic, and Cre- 
taceous age. He defines it as a triangular area 
with its base along the west coast of Borneo 
from Cape Datu on the north to Cape Sambar 
on the south, and its apex in the Miiller Moun- 
tains, about the centre of the island. The north- 
ern side he defines as running southeast from 
Cape Datu, through Mount Nuit and the Madi 
Plateau to the Miiller Mountains. The most 
significant change in lithology and tectonics 
occurs, however, along the line of the Lupar 
Valley, further North, where it is therefore more 
appropriate to place the northern side of the 
'continental core' (see Haile, 3, 91-100). Shelf 
conditions obtained along the northern margin 
of this 'continental core' in Jurassic and Creta- 
ceous times, while further North a great geosyn- 
cline developed in the Cretaceous. 

EPE1ROGENIC MOVEMENTS IN 
THE CRETACEOUS 

The main epcirogenic movements in the 
Cretaceous were slow with interrupted subsidence 
on the shelf (southern area) from early Jurassic 
to late Cretaceous times, and rapid subsidence 
in the geosyncline (northern area), probably 
beginning in the Cenomanian. Thick conglom- 
erates occur in the Seberuang Cretaceous about 

120 



the base of the Cenomanian, which may mark 
uplift in the southern area, occurring at the same 
time as, and compensating for, the beginning of 
rapid subsidence in the northern area. In the 
northern area sedimentation continued uninter- 
rupted into Eocene times, and there is no evidence 
in West Borneo of an orogeny in the Cretaceous. 

REFERENCES 

(1) Bemmelen, R.W. van, 1949, The Geology of 

Indonesia. Government Printing Office, 
The Hague. 

(2) Haile, N.S., 1954, The geology and mineral 

resources of the Strap and Sadong 

Valleys, West Sarawak, including the 

Klingkang Range coal: Brit. Borneo 
Geol. Survey Mem. 1. 

(3) Haile, N.S., 1957, The geology and mineral 

resources of the Lupar and Saribas 
Valleys, West Sarawak: Brit. Borneo 
Geol. Survey Mem. 1 (in press). 

(4) Krekeler, F., 1932, Over een nieuw voor- 

komcn van fossiel-houdend Palaeozoi- 
kum in Midden-West Borneo. (Voor- 
loopige Mcdedeeling): De Mijningenieiu\ 
p. 167, translated in Brit. Borneo Geol. 
Survey Bull. ,2, 1955. 

(5) Krekeler, F., 1933, Aanvullende Mededeel- 

ingen omtrent het voorkomen van 
Palaeozoicum in West-Borneo: De 
Mijningenieur, p. 191 translated in 
Brit. Borneo Geol. Survey Bull., 2, 1955. 

(6) Roe, F.W., 1955, Radio-active age deter- 

minations of West Sarawak igneous 
rocks: Brit. Borneo Geol. Survev Ann. 
Kept, 76-77. 

(7) Roc, F.W., 1957, Sketch-map showing the 

geology of Borneo (compilation 1 :2,000, 
000. (in preparation) 

(8) Wilford, G.E., 1955, The geology and 

mineral resources of the Kuching- 
Lundu Area, West Sarawak, including 
the Baumining district; Brit. Borneo 
Geol. Survey Mem., 3. 

(9) Zeylmans van Emmichoven, C.P.A., 1939. 

De geologic van het Centrale en Ooste- 
lijke deel van de Westerafdeling van 
Borneo: Jaarb. Mijn. Ned-Indie, pp. 
8-186, translated in Brit. Borneo Geol. 
Survey Bull, 2, 1955. 



voLUMt 12 GEOLOGY AND GEOPHYSICS 

THE LATE MESOZOIC SAKAWA OROGENY 

TEIICHI KOBAYASHI 

Geological Institute, University oj Tokyo, Tokyo, Japan. 



The Mesozoic crustal movements were im- 
mensely clarified in Japan in the past 30 years. It 
is now thoroughly ascertained that the Sakawa 
cycle of orogeny 1 which followed the Permo- 
Triassic Akiyoshi cycle on the continental side of 
the Japanese Islands is most responsible for her 
architecture. The Eo-Nippon cordillera in the 
Jurassic period was the embryonic geanticline 
which developed into the Sakawa axis. The 
Sakawa orogeny was commenced on the inner or 
the continental side with the Oga phase at the 
transitional epoch from Jurassic to Cretaceous. 
Broadly speaking, the orogenic acme was shifted 
from the inner to the outer side and the Barremio- 
Aptian Oshima phase was spasmodic for the whole 
Sakawa orogeny. The Sakawa cycle was com- 
pleted with the batholithic invasion of the Chugoku 
granite, causing the extensive Akitsu culmination 
at about the transition from Cretaceous to Tertiary 
through which most of Japan was emerged. 

Previously (8) 1 have pointed out that the 
Palaeozoic Chichibu geosyncline was divided 
into the inner and outer sides by an axial elevation 




in the Permo-Carboniferous period. It was, 
however, an auxiliary axis. The late Palaeozoic 
foldings along the axis, as seen in the southern 
Kitakami mountains (Minato, 27), were local 
phenomena. The principal axis of the Permo- 
Triassic Akiyoshi mountains is indicated by the 
Hida gneiss and the Sangun metamorphosed 
zone (1951). 

It is quite evident that the Nagatoro metamor- 
phosed zone and the Ryoke injection zone 
indicates respectively the mio- and plio-magma- 
tic zone of the Sakawa axis, instead of the Aki- 
yoshi axis as deemed by Gorai (11 )* because the 
Maizuru zone and the Mino, Kinki and other 
arcs of the Akiyoshi folded mountains are clearly 
truncated by the Ryoke injection zone. This 
conclusion is further confirmed by the fact that 
neither discontinuity in the grade of metamor- 
phism nor structural discordance exists either 
between the Nagatoro schists and the non-meta- 
morphosed rocks on their southern side or 
between the Palaeozoic and the pre-Sakawa 
Mesozoic formation in the Chichibu zone. 



Akiyoshi Folded Mountains 

Chugoku Granite Euthohth 

Ryoke Injection Zoor 

Nagatoro Metamorphosed Zone 
Chichibu Imbricated Zon* 
Shimanio Folded Zone 
Metaorogenic C'rttaceous Formations 
Nakamura Geosyncline 



Fig. 1. Tectonic map of West Japan in the Cretaceous period. 



1 . Wakino in Tsukushi Region. 

2. Toyora Basin in Prov. Nagato 

3. Oga in Kibi Plateau. 

4. Tetori Basin in Hida Block. 

5. Yatsushiro in Province Higo. 



6. Uwajima in Shikoku Island. 

7. Sakawa in the same island. 

8. Ryoseki in the same island. 

9. Yuasa in Province Kii. 

10. Misakubo in Akaishi Mountains. 



The term, orogenic cycle, means here a genetical series of geological phenomena by which a geosyncline was developed 
into a system of folded mountains. In Japan the Chichibu geosyncline turned out the Akiyoshi mountains by the Permo- 
Triassic cycle and the Shimanto geosyncline became the Sakawa mountains by the Jurasso-Cretaceous cycle. 

121 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



In the late Triassic period the metamorphosed 
axis and the folded zone of the Akiyoshi moun- 
tains were located in the inner side of Japan, 
whereas the outer side belonged to the peri-and 
extra-orogenic zones of the mountains. The 
geomorphological and tectonic differences from 
the Akiyoshi axis to the Shimanto geosyncline on 
the Pacific side is explicitly shown by the change 
in fades and thickness of the Upper Triassic 
formations and their stratigraphic relation to 
the older ones( Kobayashi, 11). 

There is no sign of the Eo-Nippon cordillera 
in the palaeogeography at that time, but in the 
Jurassic period there is no doubt that inland 
basins were separated from the Pacific ocean by 
the cordillera (Kobayashi, in these proceedings). 

The regional metamorphism has presumably 
taken place in the core of this geanticline. Sub- 
sequently the Nagatoro schists and phyllites 
were folded and intruded by the Besshi ultrabasic 
rocks. Still later, acidic magma has been injected 
lit-par-lit in the rear part of the cordillera, yield- 
ing the Ryoke gneiss. At length the Ryoke zone 
was thrust upon the Nagatoro metamorphics. 
This phase of dislocation is called "Kashio", 
because the Kashio mylonite was produced along 
the Median Tectonic Line. 

As pointed out already (8), a strong crustal 
deformation was produced not merely in a short 
time-interval indicated by a discordance. The 
amount of deformation increases by repeated 



crustal movements of not only short intervals 
but also longer durations when sediments were 
accumulating. It is interesting to see that the 
sequence happens to be unbroken or only a little 
broken where a post-Sakawa syncline lies on a 
Sakawa syncline. Such a synorogenic conformity 
or disconformity in the intra-orogenic zone is, 
however, local. As a rule it transmits soon into 
a clino-unconformity within a short distance. 

These stratigraphic aspects can now be illus- 
trated in greater detail than I have formerly 
shown. In Nagato and Tsukushi the late Meso- 
zoic crustal deformations can be analysed into 
8 stages of development, namely, those of (1) 
the Toyora-Toyonishi interval, (2) the Toyonishi 
epoch, (3) the Toyonishi-Wakino transition, (4) 
the Wakino epoch, (5) the Wakino-Inkstone 
interval, (6) the middle Inkstone epoch, (7) the 
Inkstone-Yawata interval and (8) the post-Yawata 
age (Matsumoto, 16, 51). 

The paralic Toyonishi and limnic Wakino 
series are typical orogenic sediments. The 
Wakino lake had been brought to being before 
the Toyonishi embayment turned out land. This 
transitional epoch was the climax of the Oga 
disturbance. The Inkstone series which overlies 
them disconformably is distributed extensively 
and the discordance becomes stronger where it 
covers the Toyora and older formations. 

While the discordance at the base of the 
Ryoseki series is angular in the northern Yuasa 
basin, in the Ryoseki basin it overlies the Permian 



The Cretaceous and Upper Jurassic formations in Japan. (U : Uwajima in Shikoku Island). 



Age 


Series 


Southwest Japan 


Northeast Japan 


Akitsu 

Izumt 
I- Sakawa 

Os hi ma 
(Kashio) 

1 Oga 


Hida 


Tsukushi 


HigD 


Kii 


U, 


Kitakami 


Hokkaido 


Upper 
Senon. 


Hetonai 














Hakobuchi 


Himenoura 


Toyajo 
Kanaya 


R 

8 

55 


Kuji 
Miyako 

I X-rXr~t_~< r*_>~ii 


Lower 
Seuori. 


Urakawa 


Yawata 


Up. Yezo 


Turon> 
Cenoman. 


Gyliak 


Inkstone 


Mifune 


Mikasa 
Sandst. 

Mid. Yezo 


Akaiwa 


Albian 
Aptian 


Miyako 


Yatsushiro 


Miyako 
Oshima 
Ryoseki 


| Upper Shimanto 


Hinagu 


Upper 
Neocom. 


Oshima 


Wakino 


Oshima 


Oshima 
Ayukawa 

Hashiura 


Low. Yezo 


Lower, 
Neocom. 


Ryoseki 


Itoshiro 


Toyonishi 


Ryoseki 


Sorachi 


Malm 


Torinosu 


Kuzuryu 


Toyora 


Torinosu 


Torinosu 


Ag* 


Series 


Akiyoshi Mt& 


Sakawm Folded Mountains 


Yezo 
Geosyncline 


Phase 



122 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



disconformably. Thus the influence of the 
pre-Ryoseki movement on the outer side was 
much different among places. In central Shikoku 
it is clearly demonstrated that the embryonic 
folding grew gradually through the early Creta- 
ceous period. The palaeogeographic changes 
were great at the Oshima and Sakawa phases not 
only in the sedimentary basins but also in their 
background (Kobayashi, Huzita and Kimura, 13). 

In the Yatsushiro district in Higo the Sakawa 
phase can be splitted into two subphases where 
the earlier one at the middle Miyako epoch was 
stronger than the later one (Matsumoto and 
Kammera, 20). In Shikoku, on the contrary, 
the early subphase is insignificant and only the 
later one or the Sakawa phase proper is distinct. 
Thus the paroxysm came earlier in Yalsushiro 
on the inner side than in the Sakawa and other 
basins on the outer side of the Chichibu imbri- 
cated zone. 

In the Yuasa and a few other basins the pre- 
and post-Sakawa formations form the syncline- 
on-syncline structure. Although the discordance 
is weak between them, the base of the Gyliakian 
formation in the Yuasa basin is well marked off 
by a boulder conglomerate. It is further remark- 
able that the Miyakoan formation directly over- 
lies the Palaeozoic on the south side of the basin 
and the Urakawan on the Palaeozoic on the other 
side with an angular unconformity (Matsumoto, 
16). In the Akaishi mountains the Oshima or 
Miyako series of Todai incorporates with the 
older formations in the imbricated structure of 
the Chichibu zone, whereas the Gyliakian of 
Misakubo rests on the imbrication unconforma- 
bly and forms an open syncline. 

In the Shimanto folded zone the Lower 
Cretaceous and older formations are extensive and 
all folded together intensely, whereas the Upper 
Cretaceous Nanyo formation is restricted to 
occur near Uwajima in western Shikoku. Further 
to the South there was the Nakamura geosyncline 
where the Cretaceous and Palaeogene formations 
were accumulated. 

It is difficult to correlate the metamorphism 
and plutonism in the deeper zone with the crustal 
deformation in the shallower zone. However, 
it can be judged that the Nagatoro metamorphism 
has taken place mainly in the Jurassic period, 
because it occurred in the core of the Eo-Nippon 
cordillera and because the metamorphic rocks are 
sometimes met with in the Ryoseki conglomer- 
ates. As seen in Shikoku, granitic rocks sporadi- 
cally increase in size and number in the Miyakoan 
conglomerate. This fact suggests that the Kashio 



phase of dislocation was slightly earlier than 
the Oshima phase, if they are not coeval. In 
central Kyushu the Ryoke gneiss and Nagatoro 
schists are overlain by the upper Miyakoan or 
Gyliakian series. 

Subsequent to the Kashio phase the Chichibu 
zone was imbricated and the Shimanto zone 
folded. In the Kii peninsula the Nagatoro zone 
thrust itself upon the Chichibu (Kimura, 7) and 
the northern Chichibu belt thrust again upon the 
southern Chichibu with low angles (Shiida, 
23; Kimura, 7). 

Because the western wing of the Sakawa 
mountains was imbricated by various thrustings, 
there must have been an obstacle in front. The 
northern wing on the contrary, was shifted toward 
the Pacific basin by itself. The Kwanto moun- 
tains at the junction with the west wing were sharp- 
ly bent toward the south. At the same time the 
Nagatoro zone was thrust upon the Chichibu 
zone, forming the Ogiriyama Decke (Fujimoto, 
4). In the north of the Kwanto tectonic line the 
domain of the Ryoke injection expanded into the 
Nagatoro zone or the Abukuma mountains. 

The southern and northern part of the Kita- 
kami mountains belongs respectively to the Naga- 
toro zone and the Chichi bu-Shiman to zone. 
There the strata are not much metamorphosed 
and the axes of foldings generally high angled. 

In the southern Kitakami mountains the 
Ryosekian Ayukawa series overlies the Jurassic 
and is overlain by the Oshima series both discon- 
formably. The last (2,200 m. thick) is rich in 
volcanic material and overlies the Permian of 
Ofunato with a weak discordance. They are all 
strongly folded by the Oshima orogeny. In the 
northern Kitakami the basal conglomerates of 
the Miyako series abbut with the folded Neoco- 
mian and older rocks and the series (250 m.) 
is gently tilted to the east. At Kuji the Urakawa 
series (600 m.) dips no more than 15 degrees and 
is disconformably overlain by the Palaeogene 
(Onuki, 22). 

In Central Hokkaido the Sorachi group which 
is built up mainly by andesitic and basaltic tuffs, 
siliceous shale and Radiolarian chert, indicates 
an intense volcanism within the Yezo geosyn- 
cline. It is overlain by the Yezo group (5,000 m.), 
unconformably in part. The ammonite-bearing 
mudstone facies is prevalent in the group, but the 
Trigonian sandstone of Mikasa wedges into the 
middle part from the west, showing the Gyliakian 
regression caused by the upwarping of the Kita- 
kami zone in the Sakawa phase. The Hetonaian 
Hakobuchi sandstone (900 m.) represents the 

123 



PROCELDINGS Ol Tllfc NINTH PACIFIC SCILNCh CONGRESS 



Southern Kitakami 



Oshima 



Northern Kitakami 
Kuji 



Central Hokkaido 



Hakobuchi 
Sandstone 




Miyako 





Sakawa Folded Mountains 

Fig. 2. Simplified sections showing the relation between the Sakawa folded mountains and Yezo geosyncline. 



Sorachi vv v v w 
Group 
Yezo Geosyncline 



regression at the closing of the Cretaceous period. 
It is disconformably overlain by the Palaeogene 
of the Ishikari coal-field (Matsumoto et al.. 79). 

The modification of the Akiyoshi mountains 
by the Sakawa orogeny is quite different between 
the granitized Hida zone and the non-granitized 
Yamaguchi zone and between the basement rocks 
and blanket formations. The well consolidated 
gneiss zone suffered from compressive block 
movement. The Tetori series on such blocks 
is nearly horizontal or only gently undulated 
except for their boundaries where it is abruptly 
flexured and cut by faults. These faults are mostly 
reverse in vertical section and diagonal to the 
Akiyoshi trend in plan (Kobayashi, 8). 

In the non-granitized terrain the Upper 
Triassic and Jurassic formations form structural 
basins or brachysynclines which are regardless of 
the arcs of their basement. It happens, however, 
that these blankets are folded almost as strong as 
their basement and the structures of the supra- 
and sub-formations are subconcordant. This 
kind of deformation is met with in the Hida 
plateau in the non-granitized zone near its 
boundary with the granitized zone. 

It is certainly interesting to see the similarity 
of the post-orogenic modification between the 
Akiyoshi and Sakawa mountains which suffered 
respectively from the Sakawa orogeny and the 
middle Tertiary Oyashima disturbance. The 
Palaeogene and older sediments in the Nakamura 

124 



geosyncline are strongly folded. The deformation 
of the Upper Cietaceous formation becomes 
weak in the Shimanto and northern zones. Its 
folds are almost closed in the south but wide 
open in the north of the Uwajima area. The 
open folds of the post-Sakawa formation can 
also be seen in the Yuasa and Misakubo areas 
in the Chichibu zone. It happens, however, that 
the Upper Cretaceous formation is disturbed 
almost as much as the Lower Cretaceous one. 
The deformation in such intensity is, however, 
confined to the meta-orogenic ditch which was 
later folded in between the two sides by strong 
compression. In the well granitized Ryoke 
zone the Cretaceous formation is either simply 
tilted or gently undulated. 

- In the inner zone of West Japan the Wakino 
and later formations are quite different from the 
Toyonishi and older ones in the intensity of 
deformation, because the orogeny was strongest 
in the Oga phase. The volcanism has taken 
place in the zone through the Cretaceous period, 
but most active in the Inkstone epoch. In the 
early stage andesite and porphyrite were prevalent, 
but later liparite and quartz-porphyry took their 
place. In the Kitakami mountains the eruptions 
of andesite took place in the Oshima epoch and 
liparitic ones in the Gyliakian or later. 

Finally there took place the batholithic invasion 
of the Chugoku granite on a large scale, causing 
extensive culmination near the end of the Cretace- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



ous and the beginning of the Tertiary period. 
The Palaeogene formations on the granitized 
basement in northern Kyushu are not much 
folded and generally undulated, faulted or 
flexured. Except for the Nakamura geosyn- 
cline, where the boundary between the Cretaceous 
and Tertiary systems is obscure, the Senonian is 
disconformably overlain by the Palaeogene 
formation. In Japan there is no sign of orogeny 
between them. 

In the maritime province of USSR, the Oga 
phase is marked ofT by the basal conglomerate of 
the Valangian stage which is transgressive. The 
Nikanian coal-bearing in Ussuri is composed of 
limnic or paralic sediments of Neocomian age 
and is unconformably overlain by the tufTaccous 
Nikan, the approximate equivalent of the Jnk- 
stone scries. There were crustal movements 
before the Aptian and Emscher which corre- 
sponds to the Oshima and Sakawa (or Izumi) 
phase. While the Senonian is extensive in Japan 
on the Pacific side, it is limited in the maritime 
province as well as on the continental side of 
Japan. The passage beds from Senonian to 
Palaeogene are rich in volcanic material and yield 
fossil plants resembling the Laramie flora. The 
Werchojansk mountains in which the Lower 
Cretaceous and older formations are folded may 
be referred to the Sakawa system of folded 
mountains. 

In Korea there are two folded zones. In the 
Heinan zone extending from North Korea to the 
Liaotung peninsula (Kobayashi, 10), the Triassic 
Shorin folded mountains were considerably 
modified by the late Jurassic movement called 
Taiho by Konno (1928). Simultaneously, the 
Triassic embryonic foldings in the Yokusen 
geosyncline in South Korea has been greatly 
developed till at length the complicated imbric- 
ated structure was built up in the Kwangwoun-do 
or Kogendo limestone plateau (Kobayashi, 9). 

Wong (1927) was the first in China to point out 
the importance of the late Jurassic movement. 
He denominated it "Yenshan movement" on 
the basis of the discordance at the base of the 
Tiaochishan-Chiulungshan formation in the 
Western Hills of Peking. Since then, her Mesozoic 
history was immensely clarified, but unfortunately 
the term, Yenshan movement, had been used in 
too different ways that it became most confusing. 
Namely, it means all of the Mesozoic movements 
in China (Ting, 1929; Hsieh, 1936, 37), the 
middle Mesozoic ones (Teilhard de Chardin, 
1943), the late Mesozoic ones (Wong, 1927; 
Y.Y. Lee, C Li, and S. Chu, 1935; Huang, 



1945, 52) or just the late Jurassic one (Wong, 
1927; Lee, 14). Under the circumstances it may 
be appropriated to return to the original designa- 
tion. 

The pre-Tiaochishan movement is now known 
to be middle Dogger, instead of Malm in age 
(Comp. Comm., etc., 1956). Accordingly its 
equivalent is the Gishu, instead of the Taiho, 
movement in Korea and the Hida, instead of the 
Oga, movement in Japan. This possibly means 
that the late Mesozoic movements commenced 
earlier on the continent than on the festoon is- 
lands, although the non-marine Mesozoic bio- 
stratigraphy must be established before this will 
be concluded. At all events, the late Mesozoic 
movements are most influential for the Koreo- 
Chincsc Hetcrogen (Kobayashi, 9) comprising 
Korea and the main part of China (Huang, 6). 
The movements there occurred were, however, 
synorogenies sympathetic with the Sakawa 
orogenic cycle in the peri-continental geosyn- 
cline. 

The orogeny was accompanied by volcanism 
and plutonism, as summarized by Teilhard de 
Chardin (1938, 40). His Yenshan granite in 
China, however, may not be late Jurassic in age, 
but synchronous with the Bukkokuji granite 
(Tateiwa, 1924) in Korea and with the Chugoku 
granite in Japan. They on the whole indicate the 
batholithic invasion in a grand scale in the hinter- 
land near the end of the orogenic cycle. The age 
of the granite is in a range from late Cretaceous 
to early Tertiary. 

The late Mesozoic orogeny bears the great 
importance not only in Eastern Asia, but also in 
Southeastern Asia. In Taiwan the Sakawa 
orogeny is indicated by the unconformity at the 
base of the Cretaceous Pihou formation and its 
basal conglomerate containing schists and gneiss. 
The chert-bearing Permo-Triassic formation 
called Danau (in part), Tuhul, or Pahang indicates 
the southern extension of the Shimanto geosyn- 
cline from Japan to the Malayan peninsula 
through Luzon, Palawan and Borneo. In central 
Borneo the Neocomian overlies transgressively 
the strongly folded Bojan formation of the Danau 
complex (Oga phase). In South Borneo the 
Orbitolina-bcsiring rocks are folded and intruded 
by basic and ultrabasic rocks and they are overlain 
by the Turonio-Senonian (Sakawa phase). 

Bajocian fossils were found in Singapore, 
Aelenian ammonites in the Mae Sot basin, 
Western Thailand, Bathonian brachiopods of 
Namyau and Liassic (?) plants of Loian in the 
Shan plateau, Burma. These fossiliferous forma- 

125 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



tions had been folded together with the older 
rocks and intruded by granite before the Tertiary 
basin developed in Central Burma. 

The late Mesozoic orogeny was also strong in 
certain places around the Pacific basin. In 
western North America, for example, the Diablo 
and Oregon disturbances correspond approxi- 
mately to the Oga and Sakawa phases respectively. 
The Hokonui disturbance in New Zealand is 
nearly coeval with the Oga orogeny in Japan. 
The early Oga disturbance is well marked also in 
the Pamir by the discordance at the base of the 
Tithonio-Valangian. In Oman, on the other 
hand, the Middle Cretaceous or pre-Gosau distur- 
bance was strong. The austrische Phase in the 
Alps is nearly contemporaneous with the Sakawa 
phase in Japan. The bearing of the austrian 
or subhcrzynische Phase on the Alpine tectonics 
is, however, quite different from that of the 
Cretaceous orogeny in the Japanese islands, or 
in Eastern and Southeastern Asia, where the oro- 
genic cycle was completed by the batholithic 
invasion near the end of the period. 

REFERENCES 

(1) Chardin, P. Teilhard de, 1940, The Graniti- 
zation of China, Bull Geol Soc. China, 
19:4. 



(2) 



., 1943, The Genesis of the Western 



Hills of Peking. Geobiologia, \. 



(3) Compilation Comm. of Chinese Geol. and 

Geol. Inst, Acad. Sinica, 1956, Tables 
of Stratigraphic Sequences in Provinces 
of China. 

(4) Fujimoto, H., 1937, The Nappe-Theory 

with Reference to the Northeastern 
Part of the Kwanto Mountainland. 
Sci. Rep. Tokyo Bunrika Univ. Ser. C, 
No. 6. 

(5) Gorai, M., 1956, On the Metamorphic 

Zones of the Japanese Islands. Proc. 
8th Pacif. Sci. Congr. 1953, Phil. 2A. 

(6) Huang, T.K., 1952, On the Major Tectonic 

Forms of China. Peking. 

(7) Kimura, T., 1957, The Discovery of a Low 

Angle Thrust along the Mikabu Line 
in East Kii Peninsula, Western Japan; 
Description of Areal Geology and 
their Sedimentary Rocks. Jour. Earth 
Sci. Nagoya Univ. 2: (2). 

(8) Kobayashi, T., 1941, The Sakawa Orogenic 

Cycle and its Bearing on the Origin of 
126 



the Japanese Islands. Jour. Fac. Sci. 
Imp. Univ. Tokyo, Sect. 2, 5: (7). 

(9) , 1953, The Mountain Systems on 

the Western Side of the Pacific Ocean 
classified from the Standpoint of Gene- 
sis. Proc. 1th Pacif. Sci. Congr. N.Z. 
1949, 2. 

(10) , 1956, A Contribution to the 

Geotectonics of North Korea and 
South Manchuria. Jour. Fac. Sci. 
Univ. Tokyo, Sect. 2, 10: (2). 

(II) , 1956, The Triassic Akiyoshi 

Orogeny. Gcotek. Symp. zu Ehrcn von 
Hans Stillc. Stuttgart. 

(12) , . _ , 1960, The Jurassic of Japan and 
its Bearing on the Correlation. Proc. 
9th Pacif. Sci. Congr. Bangkok, 
1957, 12. " 

(13) , Huzita, A. and Kimura, T., 1945, 

On the Geology of the Central Part 
of Shikoku, Japan. Jour. Geol. Geogr. 
20. 

(14) Lee, C.Y., 1948, A Review of Mesozoic 

Movements in China. Contr. Inst. 
Geol. Acad. Sinica, 8. 

(15) Matsumoto, T., 1947, The Geological, 

Research of the Aritagawa Valley, 
Wakayama Pref. Rep. Geol. Inst. Fac. 
Sci. Kyushu Univ. 2: (2). 

(16) -, 1949, The Late Mesozoic Geologic 

History in the Nagato Province, South- 
west Japan. Japan. Jour. Geol. Geogr. 
21. 

(17) , 1952, A Note on the Cretaceous 

History of the Circum-Pacific Region. 
Japan. Jour. Geol. Geogr. 22. 

, 1956, The Characteristic Features 
of the Cretaceous System in the Japanese 
Island. Proc. 8th Pacif. Sci. Congr. 
1953. Philippines, 2. 

(19) _ , et al., 1954, The Cretaceous 

System in the Japanese Islands. Japan 
Soc. Prom. Sci. Tokyo. 

(20) , and Kammera, K., 1949, Contri- 
butions to the Tectonic History in the 
Outer Zone of Southwest Japan. Mem. 
Fac. Sci. Kyushu Univ. Ser. D, 3 : 
(2). 

(21) Minato, M., 1950, Zur Orogenese und zum 

Vulkanismus im Jiingeren Palaozoikum 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

des Kitakami-Gebirges, Honshu Japan. Map of Iwate Pref. 2. 

Jow Fac. Sci. Hokkaido Univ. Ser. 4, (23) Shijda } 195 , Geo]ogy Qf thc Kawakamj 

' ^ ^ District in the Northeastern Yoshino 

(22) Onuki, Y., 1956, Geology of the Kitakami, Mountainland, Nara Prefecture. Jour. 

Mountains. Explanatory Text to GeoL Nara Gakugef Univ. 1. 



127 



PROCEEDINGS Ol THE NINTH PACIFIC SCIENCE CONGRESS 



MESOZOIC TECTONICS OF THE NORTHWESTERN 
CANADIAN CORDILLERAt 

J. O. WHEELER 

Geological Survev of Canada, Ottawa, Canada. 



INTRODUCTION 

The region under discussion lies within the 
Cordilleran eugeosynclinal belt (Stille, 26: Kay, 
14, 15) and embraces central southern Yukon, 
south of latitude 63 degrees north, and northwest- 
ern British Columbia, north of latitude 58 degrees 
north. 

Interpretation of the stratigraphy of this region 
reveals that the folded Mesozoic rocks extending 
southeastwards from Selkirk, Yukon, into north- 
western British Columbia probably accumulated 
in a trough having the same position and extent 
as the present rather limited distribution of these 
rocks. This trough the Whitehorse trough 
(Wheeler. 29) was flanked on the west in late 
Triassic by a volcanic island arc, which later in 
Jurassic and early Cretaceous times became a 
tectonic land with few volcanoes. During the 
middle Cretaceous the trough was deformed and 
intruded by granitic rocks. 

GEOLOGIC SETTING 

An apparently synclinorial belt of folded sedi- 
mentary and volcanic rocks of Mesozoic age, 
intruded by a few granitic bodies, extends south- 
eastwards from Selkirk along Upper Yukon 
River valley into northwestern British Columbia 
(Fig. 1). This belt, called the Upper Yukon 
Mesozoic belt, is separated from a parallel belt 
of Mesozoic rocks in the St. Elias Mountains to 
the west by a complex of quartz-rich metamorphic 
rocks, probably older than Mesozoic (Wheeler, 
29), and granitic plutons of diverse ages. Granitic 
rocks are most abundant in the southern part of 
this complex and form the northernmost part of 
the Coast intrusions (Lord, 20) extending for 
1,100 miles southeastwards along the axis of the 
Coast Mountains in western British Columbia. 
The Upper Yukon Mesozoic belt is flanked also 
on the east by another metamorphic and granitic 
complex which separates it from a broad belt of 
Palaeozoic rocks in southeastern Yukon and 



northern British Columbia (Bostock and Lees, 
4\ Mulligan, 25). 

Just north of the Yukon British Columbia 
border, part of the Upper Yukon Mesozoic belt 
is interrupted by a complexly upfaulted block, 
named here the Atlin horst, composed of late 
Palaeozoic rocks intruded by granitic plutons 
(Aitken, 2 Christie, 7). Ultramafic rocks are 
particularly well-displayed within and around 
the margins of this horst. They are found also 
in the Upper Yukon Mesozoic belt where they 
apparently intrude rocks as young as Lower 
Jurassic and in the St. Elias Mountains where 
they cut Lower Cretaceous rocks (Kindle, 18). 

For the most part flat-lying volcanic rocks of 
Cretaceous, Tertiary, and Pleistocene age uncon- 
formably overlie all older rocks, except in the 
St. Elias Mountains where Tertiary rocks are 
overthrust by Permian strata (I.E. Muller, personal 
communication). Some of the flat-lying Cre- 
taceous volcanic rocks near the head of Yukon 
River are intruded by granitic plutons. 

REGIONAL ENVIRONMENT PRIOR TO 
THE DEVELOPMENT OF THE TROUGH 

Late Permian time was probably one of tectonic 
quiet, judging from the late Permian assemblage 
consisting principally of massive limestone, radio- 
larian ribbon-chert, and greenstone (chiefly 
flows) all of which appear to have been deposited 
in seas far from a source for clastic sediments. 

The following evidence suggest that the north- 
western Canadian Cordillera was uplifted during 
early and middle Triassic time, perhaps accom- 
panied by volcanism: (1) Lower and Middle 
Triassic strata are lacking in the region; (2) con- 
glomerate in the lower part of the Upper Triassic 
succession is widespread in northwestern British 
Columbia (E.F. Roots, personal communication); 

(3) Upper Triassic rocks locally overlie Permian 
formations unconformably (McLearn, 22; JO) 

(4) In eastern Alaska and possibly elsewhere 
greenstone occurs between Permian and Upper 
Triassic strata (Martin, 27). 



t Published by permission of the Director, Geological Survey of Canada, Department of Mines and Technical Surveys, 
Ottawa. Canada. 

128 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



62' 




Fig. 1. Generalized geologic map of part of northwestern Canadian Cordillera excluding undefoimed Cretaceous 
and Cenozoic formations. 1. Metamorphic rocks, 2. Palaeozoic rocks, 3. Mesozoic rocks, 4. Granitic 
rocks, black Ultramafic rocks. 

129 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LATE TRIASSIC TECTONICS 

Although there is little evidence concerning 
the events of the early Upper Triassic, it seems 
clear that by Norian time (late Upper Triassic) 
an elongate volcanic terrain, probably an island 
arc (Eardley, 8; Wilson, 30; Kay, 75), lay along 
the subsequent site of the axis of the Coast 
Mountains, flanked on the east by a marine trough. 
Evidence for these features comes from a regional 
consideration of the distribution, abundance, 
and character of the Upper Triassic volcanic 
rocks and in detail from the Norian stratigraphy 
around Whitehorse, Yukon. 

Regionally, the thickest sections of Upper 
Triassic volcanic rocks and those with the coarsest 
f ragmen tal materials lie in a linear belt along 
the flanks of the Coast Mountains, that is, near 
the western margin of the Upper Yukon Meso- 
zoic belt. Here, volcanic rocks, mainly andesites 
and basalts, form deposits as thick as 5,000 feet 
and contain fragmental blocks commonly a foot 
and locally up to 4 feet across (Kerr, 16 9 17; 
Wheeler, 29). Northeastward and eastward 
Upper Triassic volcanic rocks appear to be less 
abundant (Tozer, 28; JO) and to date have not 
been found cast of the eastern margin of the 
tipper Yukon Mesozoic belt. Although volcanic 
rocks occur in the Upper Triassic formations in 
southeastern Alaska (Buddington and Chapin, 
5) they are absent northwestward along strike in 
the St. Elias Mountains (Muller, 24) and in the 
eastern Alaska Range (Moffit, 23). 

In the Whitehorse area, north of the Atlin 
horst, coarse Norian volcanic breccias and con- 
glomerates of nearby westerly derivation (Wheeler, 
29) are intercalated with andesitic and basaltic 
flows along the eastern flank of the Coast Moun- 
tains. This assemblage grades eastward over a 
distance of about 20 miles into a thick succession 
of greywackes, siltstone, and argillites showing 
graded bedding. Twenty miles farther east, near 
the eastern margin of the Upper Yukon Mesozoic 
belt, equivalent Norian beds are a heterogeneous 
apparently littoral assemblage of greywackes, 
agrillites, pea-sized conglomerate, and limestone 
beds containing corals and abundant fragments of 
crinoid stems and molluscs. This change in 
character of Norian beds across the Upper Yukon 
Mesozoic belt may be interpreted as a section 
across a sedimentary basin receiving detritus 
from s volcanic terrain to the west and also 
perhaps from a rather subdued or remote area to 
the east. 

Since Upper Triassic marine sedimentary 
rocks also abound in the eastern part of the 

130 



Mesozoic belt at the southeastern end of the 
Atlin horst ( 10) and at intervals along the eastern 
flank of the Coast Mountains (Kerr, 16; 17) they 
probably were deposited in a more or less contin- 
uous trough east of the volcanic arc. 

By latest Norian, however, the volcanic arc in 
this region became inactive and limy muds without 
volcanic materials were deposited right across 
the trough forming the widespread latest Norian 
limestone. 

EARLY JURASSIC TECTONICS 

The quiet period at the end of the Norian was 
abruptly terminated by the sudden and rapid 
uplift of the dormant volcanic arc. Coarse 
debris was supplied to the western margin of the 
Whitehorse trough and finer detritus was carried 
farther east to its central part. Some sediments 
were also derived from east of the trough (Fig. 
2). Evidence for the disposition, character, and 
timing of these uplifts is provided by the Lower 
Jurassic stratigraphy of the region. 

Uplift west of the trough is indicated by the 
Lower Jurassic conglomerates and erosional 
unconformities both within the Lower Jurassic 
succession and between the Upper Triassic and 
Jurassic formations near the western margin of 
the Upper Yukon Mesozoic belt. The conglom- 
erates occur as coarse -textured, apparently 
deltaic lenses up to 4,500 feet in thickness. 
These lenses, which are of local westerly origin 
(Wheeler, 29), pinch out eastward and pass into 
a marine assemblage of rapidly deposited grey- 
wackes, siltstones, and argillites in graded beds 
occupying the central part of the belt. In the 
Whitehorse area, the thickness of Upper Triassic 
rocks removed by erosion before the Lower 
Jurassic conglomerates were laid down increases 
westward from the central part of the Upper 
Yukon Mesozoic belt. For instance, in the 
central part of the belt the two units may be 
conformable, but 10 miles west, at least 700 feet 
of Upper Triassic rocks are missing below the 
base of the Lower Jurassic conglomerate (Wheeler, 
29). In Taku River area, British Columbia, 
unconformities within and below the Lower 
Jurassic formations in the southwestern part of 
the area are not recognized to the northeast 
(Kerr, 17). 

The sudden appearance in early Jurassic time 
of these conglomerates, composed principally of 
volcanic and granitic debris and containing vir- 
tually no metamorphic detritus, indicates that 
the granitic bodies were emplaced in the volcanic 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



LA ,125 _120 



IEGEND 

Secf/ons containing much conglomerate 
Sections containing mostly argillaceous rocks 
Sections containing mostly arenaceous rocks 
v v * Sect/ons containing volcanic rock* 
Probably land 

Terrain from which granitic rocks were 
probably derived 

Probable areas of deposition 

| J Paleogeography unknown 

Data for north central British Columbia from 
Tipper /954 



YUKON TERRITdRY 



BRITISH COLUMBIA 



PACIFIC OCEAN 




Fig. 2. Palaeogeographic map of northwestern Canadian Cordillera during the early Jurassic (late Lias). 



131 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



rocks of the island arc just prior to or during these 
uplifts. These bodies may have been genuine 
intrusions or faulted parts of older granitic terrains. 
Such older terrains have been discovered along 
the eastern flank of the Coast Mountains beneath 
Permian (Aitken, 2) and Upper Triassic (JO) strata 
and in southeastern Alaska supplied granitic 
debris to Silurian and Devonian conglomerates 
(Buddington and Chapin, 5). 

The conglomerates probably formed in res- 
ponse to rapid uplift which may have been 
assisted by faulting and was not everywhere 
synchronous west of the Whitehorsc trough. 
These circumstances are indicated by the coarse 
conglomerates marking the western margin of 
the trough (Fig. 2) that appear at different 
stratigraphic levels at different places. 1 

Conglomerates in the eastern part of the Upper 
\ ukon Mesozoic belt near Whitehorse were 
probably derived from the east on the following 
evidence: conglomerates in the eastern part of 
the belt, forming the basal member of the Jurassic 
succession, differ from the irregularly distributed, 
coarse lenses rich in granitic debris in the western 
part of the belt by containing few granitic frag- 
ments and by having a more or less uniform 
thickness no greater than 600 feet; basal conglom- 
erates near the eastern margin of the belt 
contain limestone blocks up to 12 feet in size, 
presumably of local origin; and conglomerates 
derived from the west pinch out eastward and do 
not appear to have been deposited in the eastern 
part of the trough (Wheeler, 29). 

In view of the uncertain relations between the 
Jurassic and Upper Triassic formations in the 
eastern part of the Upper Yukon Mesozoic belt 
little can be said of the tectonics east of the 
trough other than that land, composed mainly 
of volcanic and sedimentary rocks and sparingly 
of granitic rocks, lay in this zone in early Jurassic. 

LATER JURASSIC AND 
EARLY CRETACEOUS TECTONICS 

Nowhere in this region has strata of definite 
Middle Jurassic age or a complete section of the 



Jurassic been recognized. Middle Jurassic strata 
may, however, be represented by the siliceous 
clastic sedimentary rocks lying several hundred 
feet above late Lower or early Middle Jurassic 
fossils west of Whitehorse and by similar rocks 
beneath Upper Jurassic ( ?) and Lower Cretaceous 
beds west of Lake Laberge (Cairnes, 6). 

In contrast with the marine and coarse deltaic 
sediments deposited in the early Jurassic the 
nonmarine beds laid down in the later Jurassic 
and early Cretaceous in the Yukon contain coal 
seams, abundant fragments of quartz, quartzite, 
chert, and sodic plagioclase, and only a few beds, 
up to 50 feet thick, of relatively well-sorted 
conglomerate. 

Such a change probably resulted from a com- 
bination of factors. One of these may have 
been the complete destruction of mafic rocks and 
minerals by increased chemical weathering due 
to less rapid uplift of the western source under 
the more liumid climate of the later Jurassic and 
early Cretaceous. Conditions like these are 
indicated by coal seams up to 10 feet in thickness, 
numerous plant fragments, and the relative thin- 
ness of the conglomerate layers. If the source 
area had essentially the same composition as 
before, that is, volcanic terrain containing bodies 
of granitic rocks bearing potash feldspar, the 
humid environment would favour the preserva- 
tion of potash feldspar over plagioclase (Goldich, 
77). In the Upper Jurassic (?) and Lower Cre- 
taceous sediments, however, potash feldspar is 
absent though sodic plagioclase abounds together 
with stable quartz, quartzite, and chert. Therefore, 
another factor, namely a change in composition 
of the source area to one of a highly siliceous 
nature may have principally governed the change 
to siliceous sediments in the later Jurassic and 
early Cretaceous in the Yukon. Such siliceous 
source rocks may have been the prc-Mesozoic 
"quartz-rich metamorphic rocks or the Permian 
and older chert-bearing formations on both 
sides of the Upper Yukon Mesozoic belt. If 
these formations were the source rocks, then, 
west of the Whitehorse trough they may have 



i For example, conglomerate underlies beds containing Arniocerasl sp. of probable Lower Lias (early Lower Jurassic) 
age a few miles northwest of Whitehorse. Conglomerates west of Whitehorse form a thick section including beds 
having Lower Lias Arniocerasl sp. near the base and terminating upward just beneath beds holding Harpoceras sp. of 
Upper Lias (late Lower Jurassic) age. Conglomerate lies directly on Lower Lias beds containing Psiloceras sp. and 
Arnioceras n. sp. west of Lake Laberge, Yukon (Lees,7P), a few hundred feet above beds containing Upper Lias Harp- 
oceratids south of Carcross, Yukon, and well above strata holding Lower Lias Arnioceras sp. southwest of Atlin, 
British Columbia (J.D. Aitken, personal communication). Conglomerates also occur above and below late Lower or 
early Middle Jurassic Hildoceratids near Carmacks, Yukon (Bostock, 3), and above and below beds containing Upper 
Lias ammonites about half-way between Bennett and Atlin, British Columbia (R.L. Christie, personal communica- 
tion). Conglomerates in the Taku River area, British Columbia, are restricted mainly to the lower part of the Lower 
Jurassic (Frebold, 9). 

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VOLUME 12 



GEOLOGY AND GEOPHYSICS 



been exposed in the uplifted core of the tectonic 
land which lay west of the zone formerly occupied 
by a volcanic and granitic highland in early 
Jurassic time. By the later Jurassic and early 
Cretaceous the highland was probably worn 
down and overlapped by nonmarine sediments 
derived from the siliceous source to the west. 
This interpretation is supported to some degree 
southwest of Whitehorse where conglomerate 
like that in the Upper Jurassic (?) and Lower 
Cretaceous formation apparently unconformably 
overlies quartz-rich melamorphic rocks west 
of the Upper Yukon Mcsozoic belt (Wheeler, 29). 

LATE JURASSIC AND EARLY 
CRETACEOUS PALAEOGEOGRAPHY 

In late Jurassic and early Cretaceous the White- 
horse trough appears to have been segmented 
into a more or less restricted nonmarine basin in 
the Yukon separated by a land area from a marine 
environment in northwestern British Columbia. 
This is suggested by the limitation of nonmarine 
sediments to an area northwest of the Atlin horst 
and by the Upper Jurrassic and Lower Cretaceous 
brackish-marine sediments in northwestern Bri- 
tish Columbia which become coarser northward 
towards a probable source area north of latitude 
58 degrees (10). 

The western limit of the source area west of 
the nonmarine basin in the Yukon is delineated 
by the conglomerate associated with coal seams 
at the base of the marine Lower Cretaceous 
succession in the eastern part of the St. Elias 
Mountains. This conglomerate, however, is 
missing at the base of the succession a few miles 
to the west (Kindle, 18). 

DEFORMATION OF THE TROUGH 

In mid-Cretaceous time the rocks in the trough 
were deformed and folded mainly parallel to the 
northwesterly trend of the trough. In White- 
horse area the structure appears to be a syncli- 
norium (Wheeler, 29) in which the subsidiary 
folds on its limbs have axial planes dipping 
towards its centre. On the west side of the 
synclinorium at least one northeasterly dipping 
reverse fault is associated with folds having 
northeasterly dipping axial planes. The folds 
were governed markedly by the competence of 
the rocks. For example, open folds prevail in 
thick accumulations of competent conglomerate 
and massive greywacke whereas tight folds occur 
in incompetent limestone and interbedded grey- 
wacke and slate. 



The areas bordering the trough, composed of 
metamorphic and granitic rocks, may also have 
been involved in this deformation but insufficient 
work has been done on these rocks to establish 
this possibility. 

The subsequent intrusion of granitic plutons 
modified the earlier fold-trends in varying degrees. 
Modification of the structures in Mesozoic rocks 
was, in general, not pronounced but profound 
changes were effected in the incompetent late 
Palaeozoic rocks exposed in the Atlin horst 
(J.D. Aitken, personal communication) 

The Atlin horst was upfaulted relative to the 
surrounding Mesozoic formations some time 
after the rocks in the trough had been folded and 
intruded by granitic plutons. Since the area now 
occupied by the Atlin horst appears to have been 
a relatively elevated region in late Jurassic and 
early Cretaceous time the relative upward move- 
ment of this block may have been initiated in the 
late Jurassic. 

TIME AND PLACE OF INTRUSION 
ULTRAMAFIC ROCKS 

On the basis of the present information the 
time of intrusion of serpentinized ultramafic 
rocks exposed within the Upper Yukon Mesozoic 
belt and in the late Palaeozoic rocks of the Atlin 
horst is uncertain. 

Ultramafic rocks in the Atlin horst are regarded 
by Aitken ( 7; 2) as having been intruded during 
the Permian on the basis of their spatial relation 
to and their intimate and irregular association 
with Permian greenstone. Those in the Mcso- 
zoic belt are elongate bodies, most of which are 
more or less sheared, occurring near faults or in 
highly deformed zones in volcanic rocks of uncer- 
tain age and apparently into clastic rocks as 
young as Lower Jurassic (Wheeler, 29). 

According to Hess (J2\ J3) serpentines in an 
alpine-type mountain system were probably 
intruded during its first great deformation. 
Therefore, assuming that Aitken's interpreta- 
tion of a Permian age for the intrusion of ultrama- 
fic rocks is correct, then, the occurrence in the 
same tectonic belt of sheared ultramafic bodies in 
highly deformed and faulted zones in Mesozoic 
rocks may be explained by assuming that they 
represent Permian intrusions displaced upward 
as solid intrusions or in fault slices into younger 
rocks by mid-Cretaceous and, perhaps to some 
degree, by the earliest Jurassic deformations. 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Although ultramafic rocks cut formations as 
young as Lower Cretaceous in the St. Elias 
Mountains it is not known when the original 
intrusion took place because this mountain belt 
has undergone several disturbances from late 
Palaeozoic to late Tertiary. 

GRANITIC ROCKS 

Granitic plutons intrude both rocks deposited 
in the Whitehorse trough which were deformed 
in mid-Cretaceous time and a group of flat-lying 
volcanic rocks unconformably overlying them. 
The plutons occur as steepwalled bodies in the 
Upper Yukon Mesozoic belt and in the Atlin 
horst and as parts of plutonic complexes on each 
side of them (Fig. 1). 

Granitic rocks are most extensive today in 
zones bordering the Upper Yukon Mesozoic 
belt where granitic rocks are known to have 
existed in the early Jurassic, the earliest Upper 
Triassic, the earliest Permian, and possibly in 
the Silurian. Whether these older granitic 
terrains are parts of one or more ancient terrains 
or whether they represent repeated intrusions 
which accompanied successive disturbances in 
the same general zone along the Coast Mountain 
belt may be answered eventually by age determi- 
nations on these granitic rocks. 

SUMMARY 

In late Triassic the Whitehorse trough was 
established in central southern Yukon and north- 
western British Columbia upon a regionally 
uplifted zone which followed a period of tectonic 
quiet at the end of the Permian. This trough 
lay east of a volcanic arc that probably extended 
along what is now the axis of the Coast Moun- 
tains. The volcanic arc became inactive in 
latest Triassic. In early Jurassic, parts of the 
dormant volcanic arc were uplifted spasmodically 
at irregular intervals to form a tectonic land from 
which coarse sediments poured into the trough 
on the east. Some sediment was also derived 
from the east. Just before or during this period 
of uplift granitic bodies were emplaced into the 
volcanic rocks of the island arc either as intrusions 
or as faulted parts of older terrains. In later 
Jurassic and early Cretaceous time the trough 
was segmented by differential subsidence so that 
in the Yukon it formed a more or less enclosed 
basin receiving siliceous elastics from the core of 
the considerably eroded tectonic land to the 
west and possibly from another siliceous terrain 
to the east. 

134 



In the mid-Cretaceous the life of the trough 
came to an end and the rocks in it were deformed 
into a synclinorium. Ultramafic rocks intruded 
in the Permian may have been displaced at this 
time. The folded rocks were partly eroded and 
next overlain unconformably by volcanic rocks. 
Finally the whole assemblage was intruded by 
granitic rocks. 



ACKNOWLEDGEMENTS 

The author is grateful to Drs. H. Frebold and 
F.H. McLearn of the Geological Survey of 
Canada for the identification of the Jurassic 
fossils from Whitehorse area, Yukon, mentioned 
in the text. He is also indebted to Drs. J.E. 
Reesor and J.A. Roddick for constructive critic- 
ism of the manuscript. 

REFERENCES 

(1) Aitken, J.D., 1953, Greenstones and asso- 

ciated ultramafic rocks of the Atlin map- 
area, British Columbia; Univ. Cal. Los 
Angeles, Ph. D. Thesis. 

(2) . , 1955, Atlin, British Columbia: 

Geol. Survey Canada Paper 54-9. 

(3) Bostock, H.S., 1936, Carmacks district, 

Yukon: Geol. Survey Canada Mem. 
189. 

(4) , and Lees, E.J., 1938, Laberge 

map-area, Yukon: Geol, Survey Canada 
Mem. 217. 

(5) Buddington, A.F. and Chapin, Theodore, 

1929, Geology and mineral deposits 
of southeastern Alaska: U.S. Geol. 
Survey Bull. 800. 

(6) Cairnes, D.D., 1910, Lewes and Nordens- 

kiold Rivers coal district, Yukon Terri- 
tory: Geol. Survey Canada Mem. 5. 

(7) Christie, R.L., 1957, Skagway map-area, 

British Columbia; Geol. Survey Canada 
P.S. Map 19-1957. 

(8) Eardley, A.J., 1947, Palaeozoic Cordilleran 

geosyncline and related orogeny: Jour. 
Geology. 55: 309-342. 

(9) Frebold, H., 1953, Correlation of the Juras- 

sic formations of Canada: Geol. Soc. 
America Bull, 64: 1229-1246. 
(10) Geological Survey of Canada P.S. Map 
9-1957. (Stikine River area, British 
Columbia). 



(11) Goldich, S.S., 1938, A study in rock weath- 

ering; Jour. Geology, 46: 17-58. 

(12) Hess, H.H., 1939, Island arcs, gravity 

anomalies, and serpentine intrusions. A 
contribution to the ophiolite problem; 
17th Internal '. Geol. Congr. Kept., 2: 
263-282. 

(13 ) , 1955, Serpentines, orogeny, and 

epeirogeny: in Crust of the Earth, 
A. Poldervaart (editor), Geol. Soc. 
America, Spec. Paper 62: 391-407. 

(14) Kay, Marshall, 1947, Geosynclinal nomen- 
clature and the craton; Bull Am. Assoc. 
Petrol. Geol., 31: 1289-1293. 



(15) 



_, 1951, North American geosyn- 



clines: Geol. Soc. America, Mem. 48. 

(16) Kerr, F.A., 1948a, Lower Stikine and 
Western Iskut River areas, British Co- 
lumbia : Geol. Survey Canada Mem. 246. 



(17) , 1948b, Taku River map-area, 

British Columbia: Geol. Survey Canada 
Mem. 248. 

(18) Kindle, E.D., 1953, Dezadeash map-area, 

Yukon Territory: Geol. Survey Canada 
Mem. 268. 

(19) Lees, E.J., 1934, Geology of the Laberge 

area, Yukon: Roy. Canadian Institute 
Trans., 20: (1), 1-48. 

(20) Lord, C.S., 1947, The Cordilleran region, 

part of Chap. VII in geology and 
economic minerals of Canada, third 
edition: Geol. Survey Canada, Econ. 
Geol. Ser., 1 : 220-245. 



VOLUME 12 GEOLOGY ANfi GEOPHYSICS 

(21) Martin, G.C., 1926, The Mesozoic strati- 

graphy of Alaska: U.S. Geol. Survey 
Bull. 776. 

(22) McLearn, F.H., 1953, Correlation of the 

Triassic formations of Canada: Bull. 
Geol. Soc. America., 64 : 1205-1228. 

(23) Moffit, F.H., 1954, Geology of the eastern 

part of the Alaska Range and adjacent 
areas: U.S. Geol. Survey Bull. 989-D. 

(24) Muller, J.E., 1954, Kluane Lake (west half), 

Yukon Territory: GeoL Survey Canada 
Paper 53-20. 

(25) Mulligan, Robert, 1955, Teslin map-area, 

Yukon Territory: Geol. Survey Canada 
Paper 54-20. 

(26) Stille, H., 1941, Einfiihrung in den Bau 

Amerikas, Borntraeger, Berlin. 

(27) Tipper, H.W., 1954, Revision of the Hazel- 

ton and Takla groups of central British 
Columbia: State College of Washington, 
Ph. D. Thesis. 

(28) Tozer, E.T., 1958, Stratigraphy of the 

Lewes River group (Triassic), central 
Laberge area, Yukon Territory: Geol. 
Survey Canada Bull. 43. 

(29) Wheeler, J.O., 1956, Evolution and history 

of the Whitehorse trough as illustrated 
by the geology of Whitehorse map-area, 
Yukon: Columbia Univ., New York, 
Ph. D. Thesis. 



(30) Wilson, J. Tuzo, 1950, An analysis of the 
pattern and possible cause of young 
mountain ranges and island arcs; Geol. 
Assoc. Canada Proc. 3 : 141-166. 



135 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 

NAVADIAN OROGENY IN NORTHERNMOST CHILEt 

GIOVANNI O. CECIONlt and FLOREAL GARCIAtt 

Emprcsa National del Petroleo, Iquique, Chile. 



INTRODUCTION 

In his excellent work "Jurassic Geology of the 
World/' Arkell ( I ) showed that while in North 
America the Nevadian Orogeny reached its 
climax, in South America no proved Jurassic 
folding had been recorded. 

Afterwards, Riiegg (9) recorded a small out- 
crop with 52 meters of Tithonian sediments, 
fortunately preserved lying unconformably over 
the Dogger "Rio Grande" formation. We pro- 
pose the name "Jaguay formation" for Riiegg's 
Tithonian rocks. 

Also, according to the same author (Riiegg, 
9) the fluvio-lacustrine Aguas Calientes forma- 
tion of Eastern Peru, assigned tentatively to a 
Neocomian Turonian age, rests transgressively 
over an old Middle-Upper Paleozoic surface, 
and also over the Jurassic. Riiegg supposed that 
there was an uplift due to the Nevadian Orogeny, 
uplift that has been always considered as little 
probable. 

Lately, W. Biese (2) described a continuous 
stratigraphic series in Cerritos Bayos, Antofagasta 
Province, Chile, which covers from Lower Lias 
up to the Tithonian. Nevertheless, we must 
point out that the faunal sequence shown by Biese 
has repetition of fossils, as Macrocephalites, 
Cosmoccras* Aspidoceras, etc. and there might 
be more faults than those shown. Besides, the 
writers do not see the reasons to assign part of 
this series to the Portlandian, Tithonian and 
Bathonian. The same opinion is supported by 
Jose Corvalan, paleontologist for "Corporation 
de Fomento de la Production," Santiago (per- 
sonal communication). 

About 60 kilometers South of Cerritos Bayos, 
in the classic locality of Caracoles, H. Harrington 
(6) described Oxfordian, Callovian and Bajocian 
formations, not showing, however, the presence 
of Bathonian sediments. 



STRATIGRAPHY OF THE COASTAL 
RANGE BETWEEN IQUIQUE AND ARICA 

Three morphological units are present in the 
Chilean territory between Iquique and Arica. 
From West to East, they are: The Coastal Range, 
the Pampa and the Andes Range. The last one 
has a few active volcanoes, but geological know- 
ledge is still very scarce; here, Galli (5) showed 
the presence of Lias and Upper Carboniferous 
rocks. 

The Pampa (=plain), probably a graben at about 
1,000 meters above sea level, has no drainage 
and is usually covered by a salt crust and in part 
supports the growth of some tamarugos (carob 
tree), hence the name Pampa del Tamarugal. 
North of Zapiga, the drainage is better developed 
and the Pampa and Coastal Range are cut by a 
few deep quebradas (^gorges) which resemble the 
East African Widian. Here the salt crust and the 
scarce vegetation disappear and the Pampa takes 
the names of the gorges, as Pampa Tiliviche, 
Pampa Tana, Pampa Camarones and Pampa 
Chaca. This last one reaches the sea level by 
steps in front of Arica. 

The Coastal Range reaches a maximum eleva- 
tion of 1,575 meters at the Atajana hill. It is made 
up of rather smooth hills, and narrows and looses 
elevation to the North. In front of the Pacific 
Ocean it is cut by an abrupt cliff with a mean 
elevation of about 500 meters. To the North, the 
Coastal Range reaches only up to the Arica cliff. 
The Geology of the Coastal Range is better known 
-due to ENAP's oil prospection during the last 
year. 

A. STRATIGRAPHY OF THE COASTAL AREA SOUTH 
OF IQUIQUE 

Caleta Ligate formation 

Type locality: Caleta Ligate, 32 kilometers 
South of Iquique. The top is the base of Punta 



1 Published by permission of the EMPRESA NACJONAL DEL PETROLED (ENAP), Santiago, Chile. 

The manuscript was critically read and translated by Carlos Mordojovich K., to whom the readers and the writers are 

indebted. 

t Stratigrapher for ENAP. 
tt Geologist for ENAP. 
136 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 1. Geographical map of Northernmost Chile show- 
ing the type localities of Jurassic and Cretaceous 
formations and their structural trend. The Cretaceous 
formations are marked by the dotted areas. 

Barranco formation; the base is not exposed. 



Maximum thickness exposed: 320 meters. Lithol- 
ogy: mainly shales and siltstones with rhythmic 
sedimentation. In the upper part there are about 
50 meters of greenish yellow sandstones with 
nodules, which rest on top of quartzites; at the 
contact there is a rich fauna and a few conglom- 
eratic lenses. The rhythmic sediments have 
been drag-folded by several 5-10 meters thick 
breccia beds from the same formation, which 
probably slipped down the slope. The texture 
shows plainly that the breccia moved from East 
to West as turbidity current. The fauna consists 
of several specimens of Terebratula, Slcphanoceras 
humphriesianum (Sow.) and Cadomiics, which 
indicate a Middle Bajocian age. 

Punta Barranco formation 

Type locality: Punta Barranco, 46 kilometers 
South of Iquique. Top not exposed; the base is 
the top of Caleta Ligate formation. Thickness : 
over 1,640 meters. Lithology: mainly micro- 
breccia, with prevalence of breccia towards the 
base. The breccia fragments are mainly made 
up of porphyritic rocks, jasper and sandstone. 
There are some interbedded green to yellow 
graywackes that grade into breccia and micro- 
breccia and some red to chocolate colored shale 
beds. A few light to dark colored shale and 
siltstone beds with syn-sedimentary folds are 
present near the top and at the contact with the 
breccias. Towards the base the breccias are well 
bedded and carry black shale slabs from the 
underlying formation. A few beds carry shell 
fragments with Terebratula. In two places well 
rounded river pebbles of acid igneous rocks have 
been observed, forming lenses within the breccia. 
It is possible that the Punta Barranco formation 
correlates with the following formation. 

Caleta Sarmenia formation 

Type locality: Caleta Sarmenia, 29 kilometers 
South of Iquique. The top is the base of the 
Caleta Santiago formation; the base is unknown. 
Thickness exposed: 1,400 meters. Lithology: 
breccias of porphyritic rocks and some dark 
shale fragments, mainly towards the base. Very 
frequently there is a gradual transition from 
breccia to yellow or green graywacke, but some- 
times the breccia might grade into chocolate to 
red shale. The upper part presents frequent 
nodules. No fossils have been found. It is 
probable that this formation, as well as the Punta 
Barranco formation, have been sedimented mainly 
by turbidity currents. The presence of some 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



porphyritic lava flows is suspected, but there are 
not enough field data to prove it. 

Caleta Santiago formation 

Type locality: Caleta Santiago, 26 kilometers 
South of Iquique. The top is the base of the 
Playa Los Verdes formation. The base is the top 
of the Sarmenia formation. Thickness: about 
600 meters at the type locality. Lithology: black 
shales with some light colored siltstones, some- 
times with rhythmic sedimentation. There are 
also very well graded silty graywackes with syn- 
sedimentary folds. The black shale presents 
some slump structures with local subaqueous 
unconformities (discordant hydrodiaieima, ac- 
cording to Sanders, 7), which are more frequent 
towards the top and at the contact with the 
breccias. Texture and structure point towards 
sedimentation by turbidity currents. The only 
fossils found are Posidonomya, which might in- 
dicate a closed marine environment, low in oxygen 
and unfavorable for the development of am- 
monites. 

Playa Los Verdes formation 

Type locality : Playa Los Verdes, 24 kilometers 
South of Iquique, Top unknown. The base is 
the top of the Caleta Santiago formation. 
Thickness: over 1,500 meters at the type locality. 
Lithology: porphyritic breccias, with some well 
bedded sandstones, which present hydrothermal 
mineralization. There arc some beds of micro- 
breccia close to a few meters of dark shale and 
light siltstone with rhythmic sedimentation which 
frequently present contemporaneous deforma- 
tions and dragfolds. Towards the top, the brec- 
cias present better bedding; also, there are blocks 
up to 4 meters in diameter. No fossils have been 
found. 

B. STRATIGRAPHY OF THE COASTAL RANGE 
SOUTHEAST OF IQUIQUE 

El Godo formation 

Type locality: El Godo railroad station, South 
of Santa Rosa. Top: a very thick series of 
porphyritic breccias. Base: another very thick 
series of porphyritic breccias and unquestionable 
porphyritic lava flows. The estimated thickness 
of El Godo formation is 2,600 meters. Lithology : 
marine sediments, with thick porphyritic breccias 
in the central and lower sections. The marine 
sediments are mainly green to dark rhythmic 
shales with Posidonomya. Few limestone beds are 
present and they are rarely oolithic. A series of 

138 



radial faults makes local correlation difficult, 
but a detailed survey allowed to establish a good 
stratigraphic column. In the middle portion, 
ammonites from the humphriesianum zone were 
found (Cadomites, Stephanoceras). H. Fuenzalida, 
from Santiago's Museo de Historia Natural, 
found in the upper part one specimen of Sphae- 
roceras, and according to him, it belong to the 
Upper Bajocian. Towards the base, abundant 
Terebratula were found, similar to those from the 
Caleta Ligate formation. We may assign them a 
Middle to Upper Bajocian age to the El Godo 
formation. 

C. STRATIGRAPHY OF THE COASTAL RANGE, 
NEGREIROS AREA 

This area is located to the North of Iquique, 
between Negreiros and Quebrada Tiliviche. 

The sedimentary section is about 3,000 meters 
thick, and has been subdivided into three forma- 
tions : Aguada, Negreiros and Agua Santa. 

Aguada formation 

Type locality: between Oficina (=Nitrate mine) 
Aurora and Oficina Aguada. The top is the base 
of the Negreiros formation. The base is not 
known. Thickness: 830 meters. Lithology: 
mainly limestones in the middle and upper section 
exposed; in the basal part and towards the top 
there are green shales and siltstones. At about 
600 meters below the top there is a rich Macro- 
cephalites fauna that seems to belong to the 
Lower Callovian. 

This formation cannot be correlated with the 
formations already described, but the 300 meters 
of limestone of the lower Chiza formation might 
belong here. 

Negreiros formation 

Type locality: between Negreiros and Oficina 
Aurora. The top is the base of the Agua Santa 
formation. The base is the top of the Aguada 
formation. Thickness: 940 meters of hard, gray, 
calcareous shale, with few limestone beds and 
some interbedded chocolate colored shale beds 
towards the middle of the formation. A few 
sandstone beds are present in the upper part. 
No ammonites have been found, but its lithology 
and the age of the boundering formations suggest 
a correlation with the Caleta Santiago formation 
South of Iquique, while to the North it might 
correlate with the upper shaly section of the 
Chiza formation. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Agua Santa formation 

Type locality: West of Negreiros, in the neigh- 
bourhood of Oficina Agua Santa. The base is 
the top of Negreiros formation. The top is un- 
known. Thickness surveyed: 1,160 meters. 
Lithology: gray to greenish gray siltstones inter- 
bedded with limestone beds and gray and green 
sandstones. Towards the upper part the green 
sediments prevail. 

Abundant ammonites have been collected in 
this formation. At a few meters above the base, 
a bed with Reineckeia would incidate the Upper 
Callovian. 265 meters higher, Reineckeia and 
Euaspidoceras are associated showing a probable 
Lower Oxfordian age, while higher up there are 
two beds with Euaspidoceras, the uppermost 
carrying also Ochetoceras and Perisphinctes. This 
last association shows plainly an Upper Oxfordian 
age. 

It is interesting to mention that in the upper- 
most part of this formation some anhydrite beds, 
up to 20 meters thick, are present, which might 
belong to the "Yeso Principal" (Main Gypsum) 
from Central Chile and Argentina. The anhydrite 
beds increase in thickness from West to East. 

Towards the North of the type locality, the 
rocks that are correlated with this formation 
according to their faunal contents grade into a 
shalier facies, decreasing the amount of sandstone 
beds, as it is seen in Pampa Tana. Farther North, 
in Quebrada Chiza, the upper section of the 
Chiza formation correlates with the base of the 
Agua Santa formation, and consists of limestones, 
siltstones and some sandstone beds. Even farther 
North, in Quebrada Los Tarros, the shaly Los 
Tarros formation might represent, according to 
its fauna, a shalier heteropic facies of the Agua 
Santa formation. 

Towards the South of the type locality, it is 
quite possible that the sandstone beds grade into 
the breccias and microbreccias of the Playa Los 
Verdes fomation, which is thicker and shows 
faster sedimentation. 

D. STRATIGRAPHY OF THE COASTAL RANGE 
BETWEEN QUEBRADA TILIVICH AND ARICA 

In the previous areas, only Jurassic rocks have 
been found, while North of Tiliviche several 
marine and continental Cretaceous outcrops have 
been discovered. 

Also, the age of the Andean Diorite intrusions 
which are quite frequent in the coastal range, may 
be studied here. The Diorite intrudes the Jurassic 
rocks which are locally metamorphosed and 



mineralized. Pebbles of Andean Diorites are 
found in the continental basal Cretaceous con- 
glomerates. Then the Diorite was intruded after 
the Upper Oxfordian and before the Tithonian- 
Neocomian. 

In Patagonia, the Andean Diorite belongs to the 
Upper Cretaceous, after the Sub-Hercynian 
Orogeny (Cccioni, 4). In the Northernmost part 
of Chile, the Diorite was intruded after the Neva- 
dian Phase. The writers cannot state that the 
Andean Diorite intrusion is gradually younger 
from North to South in the Chilean Andes, 
because the necessary data for such statement is 
fragmentary, and frequently has little paleon- 
tological support (Briiggen, 3). 

Porphyritic dikes cut very often the Cretaceous 
rocks, showing that there were at least three 
epochs of basic magmatic activity, because the 
dikes cut two series of very thick porphyritic flows. 

Cuya formation 

Type locality: In the neighbourhood of Cuya, 
lower part of Quebrada Chiza. The top is the 
base of the Chiza formation. The base is not 
exposed. Lithology: a minimum of 1,270 meters 
of dark, hard breccia beds, about 5 to 10 meters 
thick, with some interbedded dark shale and 
porphyritic flows. These rocks present a variable 
degree of metamorphism according to the prox- 
imity of the Andean Diorite intrusions. 

No fossils have been found in this formation. 
It is older than Callovian. 

Chiza formation 

Type locality: Quebrada Chiza, 15 kilometers 
East-Southeast of Cuya. The base is the top of 
the Cuya formation, with gradual transition 
between both formations. The top is a small 
angular unconformity, above which rests the 
Atajana formation. Thickness: 940 meters at 
the type locality. Lithology: marine sediments, 
that have been subdivided into three members: 
the lower member, 340 meters thick, is calcareous ; 
the middle member, 470 meters thick, is shaly, 
and the upper member, 130 meters thick, is a 
calcareous sandstone. At the base of the lower 
member several Reineckeia were found, which 
indicate a Callovian age, probably Lower Callo- 
vian. In the central part of the middle member 
Posidonomya and one Parkinsonidae have been 
found, which have not been classified as yet. 

As it has been already mentioned, it is quite 
probable that the upper member of this forma- 
tion correlates with the lower part of the Agua 
Santa formation; the middle member correlates 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



with the Negreiros formation and the lower 
member correlates with the upper part of the 
Aguada formation. 

EL Morro formation 

Type locality: Arica cliff. The top is the base 
of a porphyritic complex, with breccia and por- 
phyritic intrusions and flows, not studied in 
detail. This complex seems to be placed between 
the El Morro formation and the Los Tarros 
formation. The base is not exposed. Lithology: 
three members can be differentiated: the lower 
member, which crops out at El Morro cliff, 
consists of 400 meters of pillow lavas with inter- 
bedded limestones and green shales; the middle 
member consists of 250 meters of limestone, and 
the upper member, at least 210 meters thick 
consists mainly of chocolate colored shale. 

The paleontological contents of the El Morro 
formation has been studied before: Stehn (#, 54 
and 150) mentions Macrocephalites macroceph- 
alus Schloth.. Cosmoceras aft. ornatum Schloth,, 
Reineckeia sp. and Posidonomya dalmasi Dum.. 
which indicate a Callovian age. 

The lithology of the middle member of the 
El Morro formation is quite similar to the Aguada 
formation, while the upper member is similar to 
the Negreiros formation. 

Los Tarros formation 

Type locality: Quebrada Los Tarros, a little 
south of Arica. The base is a porphyritic com- 
plex, which may be the same found at the top of 
the El Morro formation. The top is a pronounced 
angular unconformity below the Atajana forma- 
tion. Lithology: 240 meters of dark lamined 
shale with fossiliferous concretions. The same 
Pcrisphincles and Ocheioceras sp. from the Agua 
Santa formation have been found here, showing 
age correlation, but the lithology suggests deeper 
shalier facies. 

A iajana formal ion 

Type locality: neighbourhood of Atajana hill. 
The top, well exposed at the type locality, is the 
base of the Blanco formation; the base is not 
exposed, being covered by a few meters of salt 
crust. Toward the Northeast of the type locality, 
in Quebrada Chiza, the conglomerates and 
sandstones of the Atajana formation rest on the 
higher member of the Chiza formation with a 
small angular unconformity. Lithology: a mini- 
mum of 1,400 meters of continental red sand- 
stones, conglomerates and red siltstones, frequently 
sedimented as lake deposits. They often show 

140 



suncracks with contemporaneous erosion exhi- 
bited somewhere along the line of contact between 
the fine mud and the coarser upper layer. In 
some places thin veins of gypsum are present. 
It is probable that the greater part of these sedi- 
ments has been deposited in lakes by floods 
coming from the west. 

The thickness of this formation decreases 
toward the east. 

The top is a gradual transition to a siltstone 
section alternated with marine beds; but there 
are frequent conglomerate beds with well rounded 
pebbles and oyster beds at the base of the Blanco 
formation. 

The base of the Atajana formation is not well 
exposed at the type locality, but South of Atajana 
hill coarse green sandstones of this formation are 
very close to the Upper Oxfordian shales with 
Perisphincles. Southeast of Cerro Atajana (in 
the middle of Pampa Tana) the same sandstones 
are very close to the marine limestone with 
Parkinsonia, of a possible Bajocian age. North 
of Pampa Tana this formation rests on top of 
the Chiza formation, where abundant Reineckeia 
of Callovian age are present. Also in Quebrada 
Chiza, shortly below the base of the Atajana 
formation, the same faunistic association is found. 
To the North, in Quebrada Chaca, the Atajana 
formation rests on mineralized porphyritic flows 
(Cuya formation); in Quebrada Los Tarros the 
same formation rests with angular unconformity 
over the Upper Oxfordian beds which carry a 
rich fauna of Perisphinctes and Ochetoceras (Los 
Tarros formation). 

It is interesting to note that the same beds of 
the Atajana formation are found at about the 
same topographic level resting on very different 
formations, showing an extensive surface of 
unconformity at its base. The angularity is 
exposed in Quebrada Los Tarros and Quebrada 
" Chiza, and is suspected at the type locality. Folds 
and possible faults must have developed before 
the deposition of the Atajana formation. 

This formation carries no fossils. The age is 
younger than L T pper Oxfordian and older than the 
Blanco formation, being closely related to this 
latter. 

The Atajana formation might be tentatively 
correlated with the Aguas Calientes formation 
in Eastern Peru (Riiegg, 9). 

Blanco formation 

Type locality: West of Cerro Blanco, at Pampa 
Tana. The base is the top of the Atajana forma- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



tion. The top is not exposed. Thickness: 400 
meters exposed at the type locality. Lithology: 
greenish-gray sandstones with green calcareous 
sandstone beds and gray and brown laminated 
shale. The sandstones carry abundant ripple- 
marks. At the base there are siltstones that grade 
into the Atajana formation and well rounded 
conglomerates with oyster beds. 

To the Northeast of the type locality this for- 
mation is not present. Here, the Suca formation 



rests directly on top of the Chiza formation. 
The relationship between the Blanco and the 
Suca formations is unknown. The Blanco for- 
mation might be older than the Suca formation 
and might wedge out toward the North, or there 
might be a lateral change of facies. 

One hundred and twenty meters above the 
base of the Blanco formation, several specimens 
of Argentiniceras have been collected, which 
indicate a Berriasian (Basal Cretaceous) age. 



OUEBR AD A 
CHACA 



OUEBRADA 
CHIZA 



PAMPA TANA 
NORTH AREA 



PAMPA TANA 
CENTRAL ARIA 



NEGREIROS ZAPIGA 




-: 



CO r >TA AL 5IJR DE IQUIOUE 

COASTAl ARFA SOUTH 

FROM IQU I DUE 



(Mtn Gypsum) 



d* _ , ^ ZA 

" r ' ?f 



Fig. 2. Stratigraphic correlation of the Jurassic and Cretaceous formations between Iquique and Arica in the Coastal 
Range. 

141 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Tentatively this formation could correlate 
with the Jaguay formation of Northern Perti 
(Riiegg, 9). 

Suca formation 

Type locality: Quebrada Suca, southeast tri- 
butary of Quebrada Chiza. The top is not exposed 
at the type locality; toward the east it is covered 
with pronounced angular unconformity by almost 
flat lying Tertiary rocks. The base at the type 
locality is the Atajafia formation. Thickness: 
a minimum of 2,170 meters of porphyritic lava 
flows 3 to 10 meters thick each, with some thin 
breccia and red sandstone beds which seem to 
wedge out toward the West. 

The passage from the Atajana to the Suca 
formations is gradual, starting with a few lava 
flows interbedded with the red breccias of the 
Atajana formation. 

No fossils have been found in this formation. 

STRUCTURE 

Only a few general statements about structure 
will be made here. 

South of Iquique, by the El Godo railway 
station, a wide uplift of the Jurassic rocks has 
been observed, due probably to an Andean 
Diorite laccolith. The uplift presents a general 
east-west trend, with many faults of variable 
displacement, arranged in a conspicuous radial 
pattern. Diorite is exposed east and south of 
the uplift. 

Farther south, Jurassic rocks are folded with a 
general NNW-SSE trend. 

North of Iquique, these rocks are folded with 
a N-S trend, but between Zapiga and Agua 
Santa the fold axes are again NNW-SSE. 

It is of interest to mention that the Cretaceous 
rocks seem to be folded with an E-W trend. 
There are several E-W faults, and it is possible 
that differential movements of the basement along 
these faults originated the gentle E-W folds so 
different from the main trend of the Jurassic 
rocks. 

CONCLUSIONS 

Nobody has ever doubted that there is some 
kind of unconformity in South America between 
the Jurassic and the Cretaceous. With a few 
exceptions, ArkelPs idea that "no authentical 
Jurassic folding can be recorded" in South 
America, has been generally accepted. 

142 



A gentle epeirogenetic uplift, followed by a 
uniform submergence, might originate a very 
gentle angular unconformity. The transgressive 
beds will be deposited more or less on the same 
formation. 

While discussing the stratigraphy, it was 
pointed out that the Cretaceous Atajana forma- 
tion overlaps several Jurassic formations, quite 
different in age and lithology. Besides, Jurassic 
and Cretaceous rocks seem to be folded along 
widely different trends. 

The consequence is that between the Upper 
Oxfordian rocks and the Atajana formation of 
a probable Basal Cretaceous age we have a real 
orogeny, which by definition must be Nevadian. 
The lack of enough deep gorges that cut the 
Cretaceous rocks prevent us from seeing the 
Jurassic folds directly below the Cretaceous. 

It is possible that in Northern Chile, as well as 
in Canada and Alaska, the Nevadian Orogeny 
has been gentler than in Western United States. 

After the Nevadian Orogeny the Andean 
Diorite was intruded and eroded, forming part of 
the Cretaceous basal conglomerates. The present 
writers propose the working hypothesis of a 
gradually younger age of the Andean Diorite 
towards the South of the Chilean Andes, because 
in Patagonia the Andean Diorite was intruded 
after the Sub-Hercynian Orogeny. 

REFERENCES 

(1) Arkell, W.J., 1956, Jurassic Geology of the 

World. Hafner Publ. C. Inc., New York. 

(2) Biese, W., 1957, Der Jura von Cerritos 

Bayos Calama, Republica de Chile, 
Provincia de Antofagasta. Geol Jarb. 
72, Hannover. 

(3) Briiggen, J., 1950, Fundamentos de la Geo- 

logia de Chile. Inst. Geogrdfico Militar, 
Santiago de Chile. 

(4) Cecioni, G.O., 1957, Cretaceous Flysch and 

Molasse in Departamento Ultima Esper- 
anza, Magallanes Province, Chile. Bull. 
Am. Assoc. Petrol. Geologists, 41: 3, 
Tulsa. 

(5) Galli, C., 1957, Las formaciones geologicas 

en el borde occidental de la Puna de 
Atacama, sector de Pica, Tarapaca. 
"Minerales" Rev. Inst. Ing. de Minas, 
ano 12 (56), Santiago de Chile. 

(6) Harrington, H., 1954, Stratigraphic sections. 

Unpublished report sent graciously by 
the author. 



VOLUME_12_ GEOLOGY AND GEOPHYSICS 

(7) Sanders, I.E., 1957, Discontinuities in the (9) Riiegg, W., 1956, Geologic zwischen 

stratigraphic record. Trans. The New Canete-San Juan, 13 00' - 15 24' Slid 

York Acad. of Sciences, Ser. II, 19 (4). Peru. Geol. Rundsch. 45, Stuttgart. 

(8) Stehn, E., 1923, Beitrage zur Kenntniss des (10) . , 1954, Geologia y petr61eo en la 

Bathonian and Callovian in Sudameri- faja subandina peruana. XX, Congr. 

ka. Neuen Jahrb. fur Min. etc. Beil-Bd. Intern., Symposium sobre Yacimientos 

49, Stuttgart. de Petroleo y Gas, T. IV, Mexico. 



143 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



SUB -HERCYN I AN OROGENY IN SOUTHERNMOST CHILEt 

GIOVANNI O. CECIONlt 

Empresa National del Pctroleo, Iquique, Chile. 



INTRODUCTION 

The occurrence of a Mesocretaceous orogeny 
in Patagonia has been discussed for some time 
(Steinmann, 8\ Feruglio, 4\ Groeber, 5; Wenzel 
P; Munoz Cristi, 7). Exactly when it took place, 
however, was not established. Moreover, it was 
thought that all the conglomerates of the Creta- 
ceous, and even a Tertiary conglomerate, were 
attributable to one and the same formation and 
age. They were assigned to the conglomeratic 
Valdes formation, whose type locality is Puerto 
Valdes on Isla Dawson in the Strait of Magellan. 
Jt has been found, however, that this conglo- 
meratic formation actually belongs to the Seno- 
nian and tinconformably overlies Turonian sedi- 
ments, whereas the other conglomerates belong 
to different stratigraphic horizons, as was pointed 
out earlier by the writer (Cecioni, /). They are 
not discordant and often represent a regressive 
phase due to the continued uplifting of the Palco- 
Andes, which favored the deposition of younger 
conglomerates with subrounded elements in the 
Cretaceous foredeep; it was gradually filled and 
pushed farther eastward. 

The meager data supplied by Feruglio led the 
writer to believe, moreover, that the presumed 
unconformity of the Middle Cretaceous at the 
southern tip of the Argentine Cordillera (Lago 
Argentine) might actually constitute the northern 
continuation of the Ultima Esperanza fault, 
which has been investigated not so long ago 
near the Chilean-Argentine border due south of 
the southern finger of Lago Argentine. 

Until recently, the evidence of a Mesocretaceous 
orogeny in Chile consisted almost solely of the 
unconformity exposed on Isla Dawson. No 
geological surveys had been made, nor had the 
fauna been identified where fossils were found. 

From 1951 to 1956, the writer was engaged in 
the task of investigating the more important 
questions of the Cretaceous in the Magellan 
trough. After a great deal of field and laboratory 



work, the stratigraphy was clarified and the prin- 
cipal events that had taken place during the 
period were determined. 

From time to time, progress reports on the 
investigation were published. Insofar as the 
sub-Hercynian orogeny in Departamcnto Ultima 
Esperanza is concerned, a paper prepared by the 
writer was pulishcd in the United States (Cecio- 
ni, 3). It contains the most recent bibliography 
of the geology of Chilean Patagonia. More 
specific data on the stratigraphy of the area may 
be found in the pamphlet "Chile" of the Lexique 
International de Stratigraphie, now in the process 
of being printed in Paris. 

In Departamento Ultima Esperanza, the Cre- 
taceous presents the following stratigraphic 
succession, from bottom to top: 

Sena Rodriguez formation 

Originally considered a series of tuffs, brec- 
cias and flows of rhyolite, close investigation of 
texture and structure revealed it to be a thick 
glacial deposit. When the glacier receded east- 
ward, the sea advanced from the west. The 
formation is probably Tithonian. 

South erland formation 

Composed of a clayey, sandy marine series 

362 meters thick that belongs to the Middle to 

Upper Tithonian. It is older in the Cordillera 

~zone and younger in the extra-Andean zone 

toward the east. 

Erczcano formation 

Consists of a thick series of shales with gray- 
wackes, possibly deposited by turbidity currents. 
All of this formation closely resembles the Black 
European Flysch. Its age seems to lie between 
Upper Neocomian and Aptian. Its thickness is 
estimated at 2,400 meters. 



t Published by permission of Empresa Nacional del Petroleo, Santiago, Chile. This paper was translated by Mr. Ren 

Rastorfer, New York, to whom sincere thanks are due. 
t Stratigrapher for ENAP. 
144 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Punta Barrosa formation 

Comprises 600 meters of graywackes, possibly 
originated by turbidity currents presumably at 
a time when a cordillera had already been uplifted 
toward the west. This may for the first time 
have isolated the Magellan foredeep from the 
Pacific. The formation is tentatively assigned to 
the Albian. 

Ccrro Toro formation 

Made up of different members. Toward the 
bottom are pea-green shales whose facies indi- 
cates quiescent sedimentation in closed basins 
with little oxygen. These are overlain by marls 
that call to mind the sediments of the Briancon- 
nais facies. The uppermost Cerro Toro formation 
presents the most typical and best developed 
characteristics of the orogenic Flysch; Chondrites 
and syn-sedimentary folds are well developed. 
It is of Cenomanian to Turonian age. 

Lago Sofia formation 

A thick conglomeratic series ranging in thick- 
ness from 940 to 770 meters. Both top and base 
are exposed. The shape and source of the boul- 
ders, the varves at the base and the striae inter- 
calated between the varves and the boulders 
suggest that these sediments originated in moun- 
tain glaciation. They belong to the Upper 
Turonian. 

La Vcntana formation 

Consists of 590 meters of shales with numerous 
intercalations of graywackes. This formation, 
too, presents the orogenic Flysch facies. It is of 
probable Coniacian age. 

Las Chinas formation 

Composed of 425 meters of marl presenting 
the same Brianconnais facies as the marl of the 
Cerro Toro formation. The marl here encloses 
the sedimentation of the orogenic Flysch. This 
formation may also belong to the Coniacian. 

Jorge Montt formation 

Consists of 1 ,200 meters of somewhat greenish 
or bluish shales resembling the peagreen shales 
of the Cerro Toro formation. This formation 
presents a Molasse facies and, because of the 
occurrence of Baculites ovatus, is assigned to the 
Santonian. 



Picana formation 

Comprises 400 meters of sandstones with 
Molasse facies. In the northern part of Depart- 
amento Ultima Esperanza, however, the sand- 
stone grades locally into shales and graywackes 
with syn-sedimentary folds and Chondrites, indi- 
cating a new limited orogenic Flysch facies. Far- 
ther north, this facies gives way to sandstones 
that closely resemble the Tuscan Macigno. 
These sandstones were originated by turbidity 
currents and represent a localized type of syn- 
orogenic redeposited clastic sediment with the 
facies of the orogenic Flysch. This formation is 
in all likelihood of late Santonian or early Cam- 
panian age. 

Solitario formation 

At its type locality, this formation consists of 
200 meters of shales with a few thin sandstones. 
The latter, which present a Molasse facies, occur 
with more frequency and in greater thickness 
toward the south. The formation is of probable 
Campanian age. 

La Vega formation 

About 800 meters thick, it is composed of 
near-shore sandstones with a Molasse facies. 

Natales formation 

Made up of littoral shales up to 1,000 meters 
thick, with intercalations of siltstones near the 
top. 

Dorotea formation 

Consists of littoral sandstones with cross-bed- 
ding and lenses that are carboniferous and contain 
plant remains. The maximum estimated thick- 
ness is 2,000 meters, in Cerro Cazador. All of 
these formations present the Molasse facies. They 
are of Campanian to Maestrichtian age. 

Farther up there are Tertiary Molasse deposits 
which lack the Lower Tertiary sediments that 
occur abundantly farther south. 

The conclusions which the writer (Cecioni, 
J, 563) had reached with regard to the sub- 
Hercynian orogeny were as follows: "The initial 
and final periods of the orogenic Flysch are 
represented by marly series of considerable 
thickness, the facies of which is similar to that of 
the Brianconnais or pre-Alpinian calcareous series. 
Above and below the orogenic Flysch with Chon- 
drites, green shales indicate closed and calm 

145 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



basins developed mainly before the deformation. 
The orogenic movements reached their paroxysm 
shortly before the deposition of the Lago Sofia 
conglomerates. The Paleo-Andes had been 
uplifted, and mountain glaciations were probably 
developed upon them, which favored the tran- 
sportation toward the east of gravel derived 
from rocks now found at least 150 km away. 

"After the deposition of the Lago Sofia con- 
glomerates, the orogenic movements gradually 
died out in Departamcnto Ultima Esperanza. The 
general paroxysm with emergence of the Paleo- 
Andes developed after the Turonian and before 
the Senonian, which demonstrates that the 
orogenic sub-Hercynian phase occurred also jn 
Patagonia. The last epi orogenic Cretaceous 
uplift took place while the Molasse was being 
deposited and was responsible for the Macigno. 
Once these orogenic late and minor uplifts 
ended, the deposits balanced the subsidence, and 
the Molasse series locally filled the geosyncline. 
In the meantime, the Andean diorite gave origin 
to the laccoliths of Cerro Paine, Cerro Balmaceda, 
etc., and perhaps to the Andean batholith." 

After presentation of the paper on Departamcn- 
to Ultima Esperanza, the writer completed the 
geological and paleontological survey in the 
western part of Isla Dawson, where the Middle 
Cretaceous unconformity is exposed. 

Having been graciously invited to participate 
in the symposium on "Mesozoic Orogeny in the 
Pacific Area" at the Ninth Pacific Science Con- 
gress in Bangkok, the writer considered it appro- 
priate to report on the latest findings in this 
paper. 

STRATIGRAPHY OF THE SW COAST OF 
ISLA DAWSON 

The geological survey of this part of Isla 
Dawson was carried out by the writer, assisted 
by Sr. Renato Reyes B., from March to April, 
1954. The time necessary for assembling all the 
data and compiling the final report was not 
available until 1957. Surveying the area entailed 
considerable difficulties; the coast is exposed to 
violent winds from the west and subject to sudden 
storms. 

Because the sediments of the Cretaceous under- 
went frequent tectonic disturbances, the thick- 
ness of the formations cannot be determined 
with any degree of accuracy. The formations 
are exposed either at the top or at the base. Only 
the Barcarcel formation in Bahia Friend seems 
to attain a thickness of 870 meters. However, 

146 



a sizeable portion of these sediments is covered 
by the alluvia of the Rio Friend. From a study 
of aerial photographs, however, it would appear 
that the thickness established for this formation 
at this locality is correct. 

The structural map was made on the scale 
1 : 20,000, as were all geologic sections. 

Lower Fucnles formation 

This is the uppermost Cretaceous formation 
present in the area mapped. It consists of silty 
shales with large yellow concretions. The top of 
this formation is not exposed. Its base consti- 
tutes the top of the Rosa formation, as in the type 
locality of these two formations (southern coast 
of Seno Skyring). The transition from one to 
the other is gradual. Approximately 180 meters 
above the base of the formation, numerous 
Baculites inornatus were found. This species is 
encountered also at the type locality of the 
Fuentes formation a few meters above its base. 
The lower Fuentes formation corresponds litholo- 
gically to the younger Natales formation in Ulti- 
ma Esperanza; in fact, in Departamcnto Ultima 
Esperanza Bacuhtcs inornatus are found in the 
upper portions of the La Vega formation. Thus, 
the time line passes from south to north from a 
shaly to a sandy formation, which indicates that 
the upper portion of the Rosa (or La Vega) for- 
mation is transgressive. In this part of Dawson, 
Fuentes is exposed to a thickness of 235 meters. 
It is of Campanian age. 

Rosa formation 

This formation is composed of hard, massive, 
green, glauconitic sandstones, sometimes micro- 
conglomeratic. At some points of the series, 
these sandstones exhibit good stratification, parti- 
cularly toward the bottom. Frequently these 
-sandstones contain calcareous nodules and con- 
cretions. In the center portion of this formation, 
shaly intercalations with thin carboniferous 
lenses are frequent. In the lower part, some 
sandstones display evidence of shale shatter, 
and a few pebbles are observed. Their deposition 
seems to have been caused either by submarine 
slumping or by rapid and frequent regressions 
and transgressions in the shelf itself. This was 
found to be true also of the sandstones of the 
La Vega formation, to which the Rosa formation 
corresponds (Cecioni, 1957, p. 561). The Rosa 
formation underlies the Fuentes formation and 
overlies the Barcarcel formation. Both contacts 
are gradational. The maximum thickness exposed 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



is 1,200 meters. No fossils of significance were 
found. 

Bar car eel formation 

In its type locality, the top of this formation 
constitutes the bottom of the Rosa formation, 
which was determined by correlating lithology 
and fossils. The base, however, could not be 
found. On Isla Dawson, the Barcarcel formation 
mapped on the basis of lithologioal and paleonto- 
logical correlations (Cecioni, 2) is exposed with 
top and base. It underlies the Rosa formation 
here, too, and overlies the Yaldes formation. 
Both contacts are gradational. In its upper 
portions, the Barcarcel formation presents many 
sandstone layers similar to those of the Rosa 
formation, while at its base a few layers of 
conglomerates and intraformational breccias 
are observed. Lithologically, this formation is 
characterized by the prevalence of shales; but 
in various levels a notable alternation of gray- 
wackes and shales occurs. The upper portions 
of the graywacke beds exhibit contemporaneous 
deformations or syn-sedimentary folds. The 
sandstones are coarse-grained and occasionally 
contain pebbles and shale shatter. In all probabi- 
lity, these graywackes were originated by turbidity 
currents and the formation as a whole is gener- 
ically related to the Flysch, as was already 
assumed by Kranck (6). In the center portion, 
limestone beds occur more frequently, and in 
their vicinity calcareous concretions bent shortly 
before their complete lithification were formed. 
Both concretions and limestones are generally 
rich in fossils, especially Hamites and Baculites. 
The maximum thickness of this formation, 
mapped in Bahia Friend, is 870 meters. The more 
important fossils found are Kossmaticeras theobal- 
dianum (Stol.), Neograhamites taylori (Spath), 
Hoplitcs and Inoceramus australis (Wood), indica- 
ting that the formation is definitely of Senonian 
and probably of Campanian age. The same fossils 
have been found in the Solitario formation, 
which the writer has correlated with the Bar- 
carcel formation. While related, the two consti- 
tute separate formations known by different 
names; they are not identical lithologically. 
Both exhibit evidence of disturbances in sedimen- 
tation, but the Solitario formation cannot posi- 
tively be classed with the Flysch facies. 

Valdes formation 

The type locality was established at the northern 
tip of Puerto Yaldes, between Islotes Rocosos 
and Peurto San Antonio, where the top of the 
formation which constitutes the base of the 



Barcarcel formation is exposed. The base of 
the Yaldes formation rests unconformably on 
an irregular erosion surface. In the lower part 
of this formation, it was possible to map 560 
meters of sediments without a break, and in the 
upper part, 260 meters. However, it could not 
be determined whether these two blocks adjoin 
each other or whether an invisible series due to 
faulting lies between them, which would increase 
the thickness of the conglomerates. Lithologi- 
cally, these are composed of rather angular 
elements, particularly in the lower center portion. 
Toward the bottom of the series, these elements 
become steadily coarser and finally as large as 
one meter in diameter. Toward the top, the 
elements are more rounded, more pebbly, and 
many have the shape of triaxial ellipsoids. The 
elements are generally composed of dark or red 
basic rocks, presumably lamprophyres ; but 
especially toward the base, boulders and blocks of 
Cretaceous shale arc observed as well. The 
writer did not encounter any boulders of Andean 
diorite, which at the time of deposition of these 
conglomerates had not been intruded or already 
exposed by erosion. A number of sandbeds or 
arenaceous conglomerate beds were observed 
within the conglomerate series, particularly 
toward the top. The writer was able to deter- 
mine that the basic rocks of which some of the 
elements of the Yaldes conglomerate are composed 
are the same as the ones which make up the 
numerous dikes that cut the argillaceous sedimen- 
tary series underlying the unconformity. How- 
ever, he was unable to trace the source of the 
elements composed of red basic rock or to 
ascertain whether they were of the same dark 
lamprophyric basic rock, altered and meteorized. 
This will have to be determined by future petro- 
graphic examination of the many samples collect- 
ed. The animal fossils found directly above these 
conglomerates indicate that the Yaldes formation 
is of uppermost Santonian or lowermost Cam- 
panian age. The conglomerates overlie with 
angular unconformity the shales of the Cerro 
Toro formation, which 350 meters below the 
surface of unconformity visible 7,500 meters 
south of Punta Yaldes in a small bay exposed to 
westerly winds contains Inoceramus steinmanni 
of the Turonian. The unconformity is therefore 
due to an orogeny and a post-Turonian and 
pre-Senonian transgression the sub-Hercynian 
orogeny by definition. 

Lago Sofia formation 

As in Departamento Ultima Esperanza, this 
formation consists of conglomerates whose 

147 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



elements are derived largely from the Seno Rodri- 
guez formation and from the ancient granites of 
the Cordillera. But on Isla Dawson this formation 
includes a much higher percentage of elements 
originating in the lower Cretaceous formations 
(Cerro Toro, Punta Barrosa and Erezcano), 
composed primarily of phthanites from the 
Erezcano formation. The pebbles generally are 
somewhat more rounded than the ones which 
make up this formation at its type locality. 
Limited thicknesses of this formation crop out 
at Punta Zig Zag. Between Canal Cascada and 
Caleta Layaza, however, the writer was able to 
map 1,000 meters of this formation, which 
overlies the Cerro Toro formation. The top of 
this formation is not exposed. In its uppermost 
and sandiest parts, a few meters of varves were 
observed. 

Cerro Toro formation 

In this formation, over 1,000 meters of predom- 
inantly green shale beds were mapped. They 
were found of contain Inoceramus steinmanni of 
the Turonian in the upper parts and Puzosia 
compressa of the Cenomanian in the lower parts, 
where a series of peagreen shales with dark 
patches characteristic of the lower portion of 
this formation at its type locality was observed. 
The formation shows evidence of considerable 
disturbance. It underlies the Lago Sofia forma- 
tion and overlies the Punta Barrosa formation. 

Punta Barrosa formation 

Between Canal Gabriel and Bahia Isla (or 
Canal Cascada), this formation was mapped 
to a depth of 640 meters. It is composed of 
graywackes alternating with shales, with gray- 
wackes predominating. The graywacke beds are 
generally well graded, microconglomeratic at 
the bottom and silty at the top. These sand- 
stones, which resemble the Macigno, may well 
represent a type of syn-orogenic redeposited 
clastic sediment, but satisfactory evidence is 
lacking. As at its type locality (Punta Barrosa, 
Seno Ultima Esperanza), this formation is over- 
lain by the Cerro Toro formation and underlain 
by the Erezcano formation. No fossils were 
found. The formation is tentatively assigned to 
the Albian. 

Erezcano formation 

This formation consists of shales that under- 
went some dynamic metamorphism, with occa- 
sional intercalations of light-colored silts with 

148 



small syn-sedimentary folds, whose facies may be 
referred to the Black Flysch. The formation 
was mapped to a depth of 770 meters without 
reaching the base. Some Inoceramus not more 
closely identifiable were found in places. The 
age of the formation appears to be between 
Upper Neocomian and Aptian. 

TECTONICS 

As may be seen from the attached geologic 
section, numerous faults disturb the stratigraphic 
series described above. In many cases, the shift 
of these faults cannot be determined since the 
exact thickness of the various formations is 
unknown. 

The general dip of the beds is toward SSW; 
but still older formations trending in the same 
direction are present. The faults are therefore 
thrusts. Such tectonic dislocations are quite 
frequent in the Cretaceous sediments of Patagonia 
and Tierra del Fuego, from the town of Puerto 
Natales as far as Isla Navarino. 

The Ultima Esperanza fault should have a 
shift in the neighbourhood of 2,000 meters. The 
brecciated belt extends for about 100 meters; in 
it and in its immediate vicinity, numerous lam- 
prophyric dikes occur. 

SUB-HERCYNIAN OROGENY IN 

SOUTHERNMOST CHILE 
SUMMARY AND DISCUSSION 

It has been found (Cecioni, 5) that in Departa- 
mento Ultima Esperanza the intensity of the 
sub-Hercynian orogeny reached its peak shortly 
before the deposition of the conglomerates of the 
Lago Sofia formation, probably in the Middle 
Turonian. A short distance north of the town 
of Puerto Natales in that Department, the 
sediments of the Cretaceous were not disturbed 
excessively by this orogenesis, which appears 
to have affected primarily the older formations 
(undated schists, granites, Paleozoic, Seno 
Rodriguez formation), which were uplifted into 
a cordillera on which mountain glaciation seems 
to have occurred that favored deposition of the 
conglomerates of the Lago Sofia formation. 
After this deposition, orogenic activity gradually 
died out, and the Molasse series locally filled the 
foredeep. In the meantime, the Andean diorite 
gave rise to the laccoliths and perhaps to the 
batholiths. 

In the south of Departamento Ultima Es- 
peranza, in the Strait of Magellan and on Tierra 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



del Fuego, the sub-Hercynian orogeny had a far 
more profound effect on the Cretaceous sediments. 
They were uplifted, eroded and then re-covered 
with a transgressive Senonian conglomerate. 
The fact that the Lago Sofia conglomerates 
are folded and faulted below the surface of 



an angular unconformity would seem to support 
the theory that the sub-Hercynian orogeny 
occurred in two successive, separate phases, with 
the first corresponding to deposition of the 
Flysch with Chondrites beneath the Lago Sofia 
conglomerates, and the second to deposition of 




Fig. 1 Map of part of Patagonia and Tierra del Fuego showing location of detailed mapping (Fig. 2) and the Ultima 
Esperanza fault. 

149 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Fig. 2 Map of part of Isla Dawson showing location of the cross section A-B-C-D-E--F-G (Fig. 3), the unconformity 
and the Ultima Esperanza fault. 



the Flysch with Chondrites on top of these con- 
glomerates. 

This theory may be refuted simply by pointing 
to the fact that the intercalated shale and gray- 
wacke members rather than the conglomerates in 
the deposits of the Lago Sofia formation present 
the Flysch facies with Chondrites. Hence, this 
150 



formation is made up of synorogenic sediments. 

We are now in a position to state the compo- 
sition of the elements of the Lago Sofia conglo- 
merates as follows: North of Laguna Azul 
(Cecioni, 3, Fig. 2) in Departamento Ultima 
Esperanza, elements composed of Paleozoic 
rocks are fairly abundant in the conglomerates. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



In the center portion of this formation that is, 
from Laguna Azul to Peninsula de Brunswick, 
elements made up of rocks from the Seno Rodri- 
guez formation are frequently encountered. Far- 
ther south, elements of the Lower Cretaceous, 
Neocomian to Aptian are present in remarkable 
number. 

These data do not point to two distinct, sepa- 
rate, successive phases in ihe sub-Hercynian 
orogeny ; they indicate merely an uneven distribu- 
tion and intensity of one and the same force 
which during the sub-Hercynian orogeny de- 
formed younger formations from north to south 
and moved the western margin of the foredeep 
still farther. Thus, while in the north the La 
Ventana and Las Chinas formations with the 
facies of Flysch with Chondrites were being 
deposited, the peak of intensity of the sub-Hercy- 
nian orogeny shifted to the south, with the 
Palco-Andes already emerged in part. Then, 
while the Jorge Montt formation with a Molasse 
facies was being deposited in the north, a geocra- 
tic phase developed in the south, with intense 
erosion of the sub-Hercynian folds. 

Later, a minor orogenic uplift occurred farther 
north and gave rise to deposition of the El 
Chinque formation with the facies of Flysch 
with Chondrites and the facies of the Macigno, 
a type of syn-orogenic redeposited clastic sediment. 

In the south, this brief resumption of orogenic 
activity seems to have occurred after the depo- 
sition of the conglomerates of the Valdes forma- 
tion, that is, while the Barcarcel formation was 
being deposited, and possibly with some time 
lag with respect to the disturbances in the north. 

On the basis of the foregoing data, the following 
conclusions representing the final findings of 
this investigation may be drawn : 

(1) The sub-Hercynian orogeny in southern- 
most Chile deformed still younger formations 
from north to south and pushed the western 
margin of the foredeep still farther east. 

(2) The sub-Hercynian orogeny as well as 
the last brief Senonian upheaval in southern- 



most Chile did not occur everywhere all at once 
and with equal force. Rather, the peak of inten- 
sity of the orogenic movements slowly traveled 
from north to south. Consequently, the Paleo- 
Andes on Tierra del Fuego are younger than the 
Paleo-Andes of Patagonia. 

REFERENCES 

(1) Cecioni, G., 1956, Distribuzione verticale di 

alcune Kossmaticeratidae della Pata- 
gonia Cilena. Boll. Soc. Geol. ItaL, 
Roma, 74. 

(2) , 1956, Significato della ornamenta- 

zione di alcune Kossmaticeratidae della 
Patagonia. Rivista ItaL di Paleont. c 
Stratigr., Milano, 62: (1). 

(3) , 1957, Cretaceous Flysch and 

Molasse in Departamento Ultima Es- 
peranza, Magallanes Province, Chile, 
Bull. Am. Ass. Pctr. Geol., Tulsa, 41 : (3). 

(4) Feruglio, E., 1949-50, Description geologi- 

ca de la Patagonia. Y.P.F., Buenos 
Aires. 

(5) Groeber, P., with A. Stipanicic and A. 

Mingramm, 1952, Geografia de la 
Republica Argentina-Mesozoico, t. II, 
p. I. Sociedad Argentina de Estudios 
Geogrdficos GAEA, Buenos Aires. 

(6) Kranck, E. H., 1932, Geological Investiga- 

tions in the Cordillera of Tierra del 
Fuego. Acta Geogr. ( Bull. Geogr. Soc. 
of Finland), Helsinki, 4: (2). 

(7) Mufioz Cristi, J., 1956, "Chile", from 

Jenks, W.F. : Handbook of South Amer- 
ican Geology. Geol. Soc. Am. Mem. 65, 
Baltimore. 

(8) Steinmann, G., 1930, Geologia del Peru. 

Heidelberg. 

(9) Wenzel, O., 1951, Conocimiento actual sobre 

la geologia de la Provincia de Magal- 
lanesy sus posibilidades petroliferas. 
Anales Inst. de Ingenieros de Chile, 
Santiago de Chile, 44. 



151 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Symposium: The Relation of Volcanoes to Geological Structure. 

Convener: Th. H. F. Klompe (Indonesia; presently Thailand) 
MAGMATIC DIAPIRISM AND TECTONIC DEFORMATION 

R. W. Van BEMMELEN 

Geological-Mineralogical Institute of the University of Utrecht, Utrecht, Netherlands. 



Concepts on the relation between volcanoes 
and geological structure depend on the geological 
theories preferred. 

Current theories on the geological evolution 
can be divided into lateral compression hypothesis 
and plutonic hypothesis (van Bemmelen, 1954, 
p. IX and p. 16). 

The first group considers the igneous pheno- 
mena as the effect of tectonic processes. They 
speak of tectonic control of igneous activity 
(Kennedy et aL 1954). The second group supposes 
the reverse relation, viz. an igneous control of 
tectonic activity (van Bemmelen 1956). These 
two groups of geological theories might also be 
characterized as those with a restricted physical 
and those with a more general physico-chemical 
line of reasoning (van Bemmelen, 1957). 

The study of the physical aspects of the earth 
was some years ago dedicated to the seismological 
section of the International Union of Geodesy 
and Geophysics (I.U.G.G.), which is now called 
the section of seismology and of the physics of 
the earth. The study of the physico-chemical 
aspects of the earth are less satisfactorily fostered 
by this organisation. This situation has led to 
a proposal of Rittmann et aL (1956) to enlarge 
the scope of the volcanological section of the 
I.U.G.G. with the study of the composition of 
the earth. In their proposal they remark that 
"on the one hand a number of geological hypo- 
theses does not take into account the results of 
geophysics and geochemistry. On the other hand, 
many geophysical calculations are based on pre- 
misses which are incompatible with well founded 
geological and geochemical facts. The laws of 
physico-chemistry are often ignored by geologist 
as well as geophysicists". 

It is a serious shortcoming of many physical 
theories (such as the contraction theory, or the 
theory of thermal convection currents in the 
substratum) that they take into account only 
reversible changes of volume and density, which 
are due to changes of temperature and pressure. 

152 



Whereas the evolution of our planet is as a 
whole an irreversible process, conform to the 
main laws of thermodynamics. In other words, 
the various forms of endogenic energy can be 
transformed one into the other, but the ensuing 
chain-reactions are accompanied by an overall loss 
of free energy and a gain in entropy. 

In the past twenty-five years the author has 
tried to pursue this physico-chemical line of 
reasoning for the explanation of the relations 
between magma tic and tectonic events. The basic 
assumption is that all geological processes are 
the result of a general strife for equilibrum, and 
that they are accompanied by readjustments of 
the distribution of matter with its associated forms 
of energy (nuclear, chemical, thermal, gravita- 
tional). These readjustments can be effected in 
two ways by means of disperse migrations of 
atoms and ions, or by means of displacements of 
matter in bulk. 

The disperse migrations of matter are the result 
of gradients of concentration, pressure, tempera- 
ture and other differences of physico-chemical 
environment. Short-range as well as long-range 
migrations may occur. These diffusions influence 
the chemical composition, causing alterations 
and transformations of one rock type in the other. 

In their turn, such chemical alterations and the 
heat balance of the associated changes of the 
chemical bonds influence the physical properties 
of the matter concerned (density, volume, viscos- 
ity, rigidity, elasticity, yield stress). 

More or less extensive parts of the earth's 
silicate mantle ( = substratum + crust) become 
too heavy or too light for the place they occupy 
in the silicate mantle, and potential energy 
accumulates in them. This potential energy is 
ultimately or intermittently released when the 
yield stresses are surmounted. 

The resulting displacements of matter in bulk 
represent the second type of readjustments in the 
distribution of matter, mentioned above. They 
tend to restore the gravitatismal equilibrium 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



which has been temporarily disturbed by physico- 
chemical processes. 

Thus geochemically generated circuits of matter 
will occur in the silicate mantle. 

All volcanic and tectonic phenomena observa- 
ble at the surface are the effect of greater or 
smaller mass-displacements in depth. Both groups 
of phenomena are generated by readjustments 
in the distribution of matter and its associated 
energy. Thus the general answer to the problem 



of the relations between volcanoes and geological 
structure, the theme of this symposium, is that 
this relation is more fraternal than parental. 

Mechanically, two types of mass-circuits in 
depth can be distinguished, which we call the 
"buoyant and the "foundering" type. 

In the "buoyant'" type of mass-circuits the 
primary forces are directed upward, trying to 
push up (according to the law of Archimedes) 
a body that has become too light for the position 



Fig. 1. Geochemically generated mass-circuits in the substratum. 



-20- 



-50- 



-100- 




-20 




-5O 



-100- 



-150 



Stage A : Secretion and rise of basaltic fraction from a 
peridotitic substratum by means of "buoyant" mass- 
circuits. 



-J50- 






ho^ discontinuity 

''7?) -* "-fXT-X 






| ^ X 

. X \ ' 



\ 



\ 



N 



\ 

\ 
^ \ 

/ 1 

. \ I 

/ 







X 



X 



\ / 

^ \ 



\ 



Stage B : Subsidence of the peridotitic residue (after the 
secretion of the basaltic fraction) by means of a "foun- 
dering" type of mass-circuit. 

153 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



EPEIROGENIC MASS - CIRCUITS 



- 20 



-40 - 



- 60 - 



-80 - 



-100 



b I i s t e r- o fib d io 1 1 ma 4 rn 

' tn *~* 




Fig 2A- Mega-circuit of the "buoyant" type Fig. 2B: Mega-circuit of the "foundering type 

Formation of a geotumor by a blister of basaltic magma Formation of a new oceanic basin due to the basification 
at the base of the crust. of a crustal segment and increase of density of the sub- 

jacent part of the substratum (secretion of the basaltic 
fraction). 



10O 




OROGENIC MASS- CIRCUITS 



2OO 30Okm 
I 



3OOkm 



-4O 



Lkm 




Fig. 3A: Meso-circuit of the "buoyant" type 

Uplift of a blister of granitic magma and migma causes 

a geanticlinal arch of the overlying part of the sialic crust. 

it occupies in the silicate mantle. 

In the "foundering" type of mass-circuits the 
primary forces are directed downward, because 
a body that has become too heavy for the place 
it occupies, pushes downward like the heavy 
plunger in a hydraulic press-system. 

The ensuing mass-circuits are coherent ener- 
154 



-40 - 



Fig. 3B: Meso-circuit of the "foundering" type 

The load of a high-level plate of high-density rocks causes 

the formation of a cauldron or basin. 

gy-systems in which the gains in potential energy 
of rising bodies are balanced by losses in potential 
energy of subsiding bodies. 

The loss of potential energy of the pressing 
parts of the system must be somewhat greater 
than the gains in the other parts, otherwise 
the engine would not work. Part of the potential 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



energy will be transformed into heat of internal 
friction or into seismic shocks, These forms of 
energy are dissipated and lost for the moving of 
the mass-circuit concerned. 

The primary forces are marked (1) in the figs. 
1, 2 and 3. They cause at the base either a centripe- 
tal accrue of matter ( (2) in figs. 1 A, 2A and 3 A), 
or a centrifugal squeezing away ( (2) in figs. 1 B, 2B 
and 3B). The surrounding belt subsides in the 
"buoyant" circuit ((3) in figs. 1 A, 2A and 3A) and 
it rises in the "foundering" type (branch (3) in 
figs. !B,2B,and3B). The branches (1), (2) and (3) 
occur simultaneously due to the requirement of 
volumetric compensation and the negligible com- 
pressability of the matter in the silicate mantle 
under high confining pressure. 

The fourth branch, however, which occurs at 
the boundary with the hydrosphere and atmos- 
phere, is not subjected to the requirement of 
volumetric compensation. Therefore, it may lag 
behind in time. This fourth branch closes the 
circuit, either by means of gravity tectonics 
(4a) or by means of erosion and sedimentation 
(4b). 

In both types of circuits matter is pushed^ 
upward, either directly by "buoyant" forces, or 
indirectly by an energy-system resembling a 
"foundering" press. 

Now if magmatic material is involved which has 
a higher mobility (lower viscosity) than the sur- 
rounding rocks, it has the tendency to ascent by 
means of diapirism, forming plutonic and 
subvolcanic intrusions or volcanic extrusions. 

The relation between the location of volcanoes 
and tectonic structure is such that the "buoyant" 
circuits show volcanoes on top of the crustal 
segment that is domed or arched upward, whereas 
in the "foundering" circuits the volcanic phenome- 
na occur in the belt surrounding the subsiding 
segments. For instance, the mountain ranges 
and island-arcs of SE Asia are pushed up by 
low-density roots and they are crowned by 
volcanoes whereever magma finds its way to the 
crest by means of diapiric ascent. 

On the other hand, the subsiding block of the 
Central Banda Basin is accompanied by a revival 
of the volcanism at the inner side of the Banda 
Arcs. This diapiric ascent of magma probably 
is an indirect result of the subsidence of the 
Central Banda block (see section at the base of 
fig. 49 in Mountain Building, p. 161, van Bemme- 
len 1954). 

On a smaller scale, the cone sheets of the 
tertiary centres of igneous activity in Scotland are 



the result of direct upward pressure of the magma 
("buoyant" circuit); whereas the ringdikes are 
the secondary effect of the sinking down of the 
central high-density block (van Bemmelen, 1937). 

A good example of the fraternal relations be- 
tween volcanic activity and tectonic structure is 
the volcano-tectonic history of the Dyngjufjoll 
Mts with the Askja Caldera in Central Iceland 
(van Bemmelen & Rutten, 1955). This volcano 
complex was domed up in late glacial time. The 
volume of the dome above the surrounding 
planes was of the order of 100 km 3 . During the 
final stages of the upheaval, basaltic lavas poured 
out profusely from several fissures in the top 
area of the Dyngjufjoll dome. The volume of 
these early syntectonic lava flows is estimated at 
10-20 km 3 . The doming of this complex and 
the diapiric ascent of magma are apparently 
two different mechanical solutions of ascent in an 
"buoyant" mass-circuit, c.q. the hydrostatic 
overpressure of an uptrusion of basaltic magma. 

This uptrusion caused a laccolithic blister of 
basaltmagma with a domed roof and extrusions 
of basalt through tension fissures in the roof. 

In the next sub-stage of the Dyngjufjoll history 
a new hydrodynamic situation had developed, 
viz. a blister of low density magma covered by a 
roof loaded with consolidated basalts of higher 
mean density than the corresponding liquid 
magma of the chamber. 

Thus this doming and the outflow of early 
syntectonic lavas had produced an inversion of 
the stable density layering. Consequently the 
cope-stone of the roof quietly subsided more or 
less vertically into the underlying magma chamber, 
causing the peripheral outflow of magma along 
fractures. By this hydraulic mechanism the 
Askja cauldron on the top of the dome came 
into existence. 

The volume of the late syntectonic peripheral 
lava outflows, which issued at the time of the 
collapse of the top part of the Dyngjufjoll dome, 
was probably somewhat greater (>10 km 3 ) 
than the volume of the Askja caldera (with the an- 
nex graben of the Osbjuop 8, 3 km 3 ). Therefore, 
these late syntectonic outflows are probably the 
combined effect of the hydrostatic overpressure 
in the rising basalt magma (just as the early syn- 
tectonic basalt flows) on which a smaller circuit 
of the "foundering" type was superimposed due 
to the collapse of the top part of the roof. 

After these volcano-tectonic processes had 
come to a halt, the basalt outflows in the Dyng- 
jufjoll area continued. These post-tectonic 

155 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



lava outflows reached the surface unhampered 
by way of tension rifts. They were no longer 
accompanied by tectonic effects. 

This picture of the volcano-tectonic evolution 
of the Dyngjufjoll volcanic complex in Central 
Iceland is typical for the fraternal relations be- 
tween magmatic and tectonic phenomena on a 
larger scale. 

REFERENCES 

Bemmelen, R.W. van, 1937, The cause and 
mechanism of igneous intrusion (with 
some Scottish examples) Trans. GeoL 
Soc. Glasgow, 19 (3) : 453-492. 

, 1953, Relations entre le volcanisme et 

la tectogenese en Indonesie. Bull. 
Volcanologique, Serie 2, Tome 18 : 
57-62. 

, 1954, Mountain Building (a study 

primarily based on Indonesia, region of 



the world's most active deformations) 
Ed. Mart. Nijhoff, the Hague. 
, 1955a, Tectogenese par gravite. Bull. 
Soc. Beige de Geologic, 64 (1) : 95-124. 

, 1955b, Involution orogenetique de 

la Sonde (Indonesie). Bull. soc. Beige 
de Geologic, M(1) : 124-152. 

and Rutten, M.G., 1955c, Table Moun- 
tains in Northern Iceland, Ed. Brill, 
Leyden. 

. , 1956, The geochemical control of 

tectonic activity, Geologic en Mijnbouw, 
Nw. Ser., IS (4) : 131-144. 

Kennedy, W.Q. et /., 1954, The tectonic control 
of igneous activity. Inter University 
Geol. Congr. 1953. Dept. of Geol. 
University of Leeds. 

Rittmann, A. et al, 1956, Newsletter of the 
Intern. Union of Geodesy and Geophy- 
sics, 5 (14) :201. 



156 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



ON THE ORIGIN OF MOON "CRATERS" AND 
THE VOLCANISM OF THE OLD SHIELDS 

H. TAZIEFF 

75 Quai dc Bourbon, Paris, France. 



INTRODUCTION 

A discussion of the origin of lunar topography 
might lead to a better understanding of the inner 
tectonics of our own globe, particularly if we 
accept the hypothesis that our satellite was born 
of a planetary "mitosis" determined by an effect 
of resonance on the powerful terrestrial tides 
caused by the sun before the consolidation of the 
earth's crust. 

If the moon is really the result of a colossal 
rupture of the earth, it is composed as the most 
recent astronomical findings tend to prove 
essentially of basaltic matter. Because of its small 
mass (1/81 of the earth), this globe, probably 
congealed to the very center, docs not possess the 
slightest trace of atmosphere: all the gases and 
liquids which the lunar "bubble" carried off' 
with it at the time of its birth have long since 
escaped into interplanetary space, and the same 
is true of the gases emitted later by volcanic 
eruptions. 

Thus there are, on the surface of our satellite, 
none of the powerful agents of erosion which have 
continuously marked the surface of the earth: 
water, ice, wind . . . Only the drastic changes of 
temperature between night and day, fluctuating 
at one and the same point between 100 above 
and 150 below zero (centigrade), seem to be 
capable of altering the structure of the rock. 
But because of the poor conductivity of the rock 
and of vacuum, the pulverization resulting from 
this change of temperature is limited to a thin 
layer at the surface. 

Everyone knows that the face of the moon is 
marked by numerous depressions known as 
"cirques" or "craters," which seem circular at 
first sight. Careful examination permits us to 
distinguish two main categories: on the one hand 
the vast cirques with horizontal bottom, ranging 
in diameter from a few dozen km. to 220 km. 
(Clavius for example); on the other hand, the 
smaller bowl-shaped craters, ranging from 100 m. 
to 3 or 4 km. in diameter. 

The visible surface of the moon reveals more 
than 30,000 of these formations and men have 
long speculated as to their origin. 



There are two classical explanations, neither of 
which seems to take account of the distinction 
between the immense flat-bottomed depressions 
and the small hollows with curved bottoms. 

THE METEORITIC THEORY 

Most astronomers incline toward the mete- 
ontic origin of the craters, which, according to 
them, results from the extremely violent impact 
of aeroliths, there being no atmosphere to pul- 
verize them or even to brake their speed. The 
kinetic energy of these masses moving at a velo- 
city of circa 15.20 km/sec is transformed into 
extreme heat when they are brought to a sudden 
stop by the lunar rock. Supposedly the meteorite 
instantly bursts into a gigantic explosion. 

In refutation of this theory it has been argued 
that no elliptical craters are observed on the moon 
though the meteorite strikes at an angle inferior 
to 45 the depression should be increasingly 
elliptical. The advocates of the meteoritic theory 
reply that the explosion itself, regardless of the 
agnle of impact, produces a circular crater, as 
has been proved too often by artillery bombard- 
ments. 

THE VOLCANIC THEORY 

The other theory is that of volcanic origin; 
its most qualified proponent is Prof. B.G. Escher. 

His two main reasons for prefering a magmatic 
origin of the lunar cirques is that the meteoritic 
theory does not explain why: 

1 ) though the size of the meteorites that strike 
the moon and consequently the diameter of the 
craters produced by their impact depends only 
on the laws of chance, a crater has never been 
observed to be overlapped by another, larger one : 
always when one depression overlaps on another, 
the newer one is the smaller (in exceptional cases 
two cirques of the same diameter overlap). 

2) Certain cirques (Copernicus, Eratosthenes, 
Archimedes, Arzachel, Tycho) are surrounded 
by a number of concentric borders, often 
separated by long, narrow terraces. 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



A volcanic origin of the craters would account 
for these characteristics; the succession in time of 
craters gradually decreasing in size would logi- 
cally correspond to a diminishing volcanic acti- 
vity; and the collapse which accompany the form- 
ation of a caldera would account reasonably well 
for the narrow terraces on the edges. 

An additional argument in favor of the volcanic 
theory is that it accounts for certain rectlinear 
alignments of craters (Hygines, Rheita, the region 
between Stadius and Copernicus) that may be 
observed on the moon. These are regarded as 
equivalent to the volcanic alignments on earth 
(Laki, Eldgja). 

The probability of meteoritic impacts almost 
continuous and disposed in a straight line is 
virtually zero. 

MAIN WEAKNESSES OF 
THE CLASSICAL HYPOTHESES 

Yet it seems to me that two important factors 
are constantly neglected in this controversy. 
The first is the existence of two classes of depres- 
sions, differing both in morphology and size: 
the relatively small cupules and the relatively 
large cirques. I believe that the genesis of the 
craters of the first category may be explained 
equally well by either theory, that some of the 
thousands of cupules with a maximum diameter 
of a few kilometers may be due to the impact of 
meteorites and others to volcanic eruptions. 

But the point on which the two classical theories 
disagree is precisely not the origin of these small 
cupules, minor depressions that can be dis- 
tinguished clearly in powerful enlargements, but 
the origin of the major depressions which have 
struck the imagination of observers ever since the 
invention of the astronomic telescope, and which 
alone have received names. 

Before expounding the third hypothesis the 
only one in my opinion which accounts for the 
formation of the principal cirques of the moon, 
I should like to call attention to a fact that cannot 
be reconciled with a meteoritic or even a volcanic 
origin : the horizontal bottoms of all the depres- 
sions. It is difficult to conceive that a crater due 
to an impact should be bordered by walls several 
thousand meters in height. But above all, one 
wonders, why, on a satellite without winds and 
particularly without rains or water courses, should 
a crater of meteoritic origin or volcano-tectonic 
collapse origin, not have preserved a trace of its 
original form, which could only have been that 
of a funnel in the 1 st case and a sink-hole in the 

158 



second ? And none of these vast lunar depres- 
sions presents so much as a suggestion of such 
a shape. How do the "meteorists" or the "vol- 
canists" explain the uniform horizontality of the 
bottoms ? 

But there is a still more serious phenomenon, 
which neither the "meteorists" nor the "volca- 
nists" engaged in the controversy seem to have 
taken into consideration: the large depressions 
in the moon are not circular. Any good photo- 
graph shows this clearly: the large lunar "craters" 
are polygonal, often even hexagonal, (figures 1 
and 2). 

As early as 1908 the French astronomer P. 
Puiseux wrote: "... The solid crust of the moon 
was constituted in all its parts by an assemblage 
of polygonal boxes, juxtaposed and imperfectly 
welded together." 

WASIUTYNSKFS HYPOTHESIS: 
CONVECTIVE ORIGIN 

In 1946 a Polish astronomer, J. Wasiutynski, 
published an important paper on the structure 
of the heavenly bodies, in which he put forward 
a highly interesting thesis: like the granules of the 
solar chromosphere or, on an infinitely smaller 
scale like the polygonal soils of the Arctic, the 
polygonal "cirques" of the moon are the conse- 
quence of the convection cells that stirred the 
basaltic magma until it definitively congealed. 

Convection currents are recognized to be a 
phenomenon widespread in nature: in any fluid 
subjected to a thermogravitic imbalance, provided 
that certain conditions of homogeneity are ful- 
filled, relatively warm and light currents rise to 
the higher discontinuity ; here they spread out and 
join with the concentric descending currents of 
relatively cool, heavy matter. Isolated, such a 
cell would be cylindrical; but juxtaposed cells, 
pressed together, are necessarily polygonal, 
hexagonal when a balance is achieved between 
them. 

As the moon cooled, the original heat of its 
magma was radiated into interplanetary space. 
The cooled portions on the surface, made still 
more dense by the loss of volatile elements, sank, 
while the inner parts, hotter and less heavy tended 
to rise. 

It is probable that the currents thus engendered 
were vast at first. Then, as the magma was dif- 
ferentiated in the course of its cooling, it resolved 
into superimposed layers, not homogeneous and 
not necessarily concentric, but more or less inter- 
locked in a highly complex way : in the moon of that 



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Fig, I. 



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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Fig. 2. 



time as in the present earth, numerous smaller 
"pockets" were probably superimposed on certain 
major discordances. The differences in latitude, 
gravity, certrifugal force, the chemical variations 
of the magma, the increasing divergences due to 
the differentiation of the lunar matter, and doubt- 
less still other factors produced a certain irregu- 
larity of physical composition. The convection 
then became localized in the various stages, 
strata, and lentils, its characteristics varying with 
their thickness and viscosity, (which increased as 
the mass cooled). As the magma became differen- 
tiated into superimposed layers, the outer cells 
of the satellite decreased in size and the prisms 
thus determined approached the perfect form: 
the hexagon. 

Finally, as the matter became too viscous, the 
outer cells of the moon were gradually immo- 

160 



bilized, the smallest last. This would explain why 
small hexagons are sometimes overlapping bigger 
^ ones, while the converse never occurs. 

Thus the lunar craters would only be the out- 
side of the last convection cells to have stirred the 
lunar magma. Their great mountainous edges 
would be formed by the piling up of congealed 
rock which the currents radiating horizontally 
pushed toward the periphery of the upper surface 
of the prisms (in accordance with the very same 
process by which the "polygonal soils" were 
formed, fig. 3). These rocks, basaltic but no 
doubt predominantly granitic (the small propor- 
tion of granite in the "pre-Pacific crust"), less 
dense than the molten magma, rose to the surface, 
and accumulated round the cells, forming in- 
creasingly large rectilinear Cordilleras. 
If we study good photographs of the moon, 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 3 Arctic Polygonal Soils. 



we observe that outside of the arenas clearly 
delimited by these mountainous borders of greater 
or lesser elevation, there are many others, general- 
ly smaller in size, which seem to be merely 
sketched or half effaced. These should probably 
be regarded as late cells, operating in a viscous 
medium already divested of its scoriaceous gra- 



nitic scum, and which have therefore remained 
without marginal "foam." 

* 
THE "CENTRAL PEAKS" 

The theory of the meteoritic origin of the lunar 
"craters" can scarcely explain the peaks that can 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



be observed near the centers of numerous de- 
pressions. The volcanic theory is also baffled: 
the terrestrial calderas nowhere provide the 
equivalent of this phenomenon, for the volcanoes 
within them are generally small in height, rarely 
single, almost always aligned on fracture zones. 

But if we accept Wasiutynski's hypothesis, the 
existence and central situation of the peaks 
become comprehensible. It is indeed in the 
central axis of the cell that are localized the as- 
cending hot currents in which crystallization was 
last to take place; thus it was here that the last 
pneumatolytes were concentrated. When this 
concentration had reached a sufficient degree 
to overcome the resistance of the surrounding 
rock, the gases erupted: a real volcanism, of a 
highly explosive character, was manifested in the 
center of numerous congealed convection cells, 
giving rise to those high, conical steep slopes 
mountains which mark the center of many poly- 
gonal cirques. 

POSSIBLE TERRESTRIAL 

CONVECTION CELLS, RIFTS 

AND KRATOGENIC YOLCANISM 

The author is not unaware of the objections 
that this theory of the moon's structure cannot 
fail to arouse. But thus far it is the only theory 
which provides a rational explanation of the 
polygonal form of the "craters" or, for that 
matter, which even dares to mention it. Even if 
we set aside the other inadequacies of the two 
main hypotheses critisized above, this major 
lacuna should suffice to discredit them. 

Until a different explanation of this polygonal 
form is offered, we are compelled to assume that 
cells of thermic convection acted on the lunar 
magma while it was still in a fluid state. 

If we accept the existence of such a phenomenon 
in the moon, it becomes equally plausible for the 
earth. The fossil cells of the moon thus support 
the hypothesis of terrestrial convection currents. 
In the last 30 years numerous geologists and geo- 
pysicist have invoked such currents to explain 
various aspects of the earth's tectonics, though 
many others deny their existence. 

On first thought it may seem impossible to find 
polygonal cirques or mountains of the lunar type 
on the surface of the earth: the granitic crust, 
fashioned and refashioned over and over again 
by orogenesis and erosion, doubtless hides the 
upper surface of the convection prisms beneath 
a thickness of 20 to 100 kilometers. Nevertheless 
it might be fruitful to reconsider the main struc- 

162 



tural lines of our globe in the light of this hypo- 
thesis. One of the most interesting regions in 
this respect might be the Pacific Ocean, and when 
the topography of its bottom has been ascertained 
with sufficient precision, when depressions, 
crests, rifts and volcanic chains have been suffi- 
ciently localized, it will doubtless be possible to 
draw important conclusions concerning the 
earth's tectonics down to a considerable depth. 

This development may not be far off; mean- 
while, however, the well-known structure of 
Africa vast depressed basins separated by long, 
narrow ranges may perhaps, if the granite-sedi- 
mentary covering and erosion are taken into 
account, be regarded as a reflection of terrestrial 
convection cells. 

A schematic map of Africa published by Arthur 
Holmes in 1944 discloses this structure; the 
polygonal outline of the borders of many of the 
basins is evident, fig. 4. 

The investigations of these last years seem to 
point at a phenomenon (cf. F. Dixey, 1956) 
which startles one at first sight and which classical 
geology, as far as the author knows, does not 
mention: these raised and distended vaults 
between vast subcircular or polygonal basins 
have been a constant feature of Africa since 
Archaean times. For at least half a billion years, 
in other words, epirogenesis has affected Africa, 
forcing these narrow ranges between the immense 
depressed basins steadily higher. The idea of 
powerful convection cells, operating since the 
congealing of the Africa kratogen, would seem 
to provide a satisfactory explanation of this 
enduring and astonishingly localized phenome- 
non. And no other factor seems to account for it. 

The graben and rifts that are one of the essen- 
tial characteristics of African geology are situated 
along the longitudinal axis of these ranges. The 
superficial tensions prevailing in the upper few 
km. of the bulges seem to be the cause of these 
spectacular clefts. The structure, presumed to be 
original, of the Red Sea graben confirms the 
hypothesis that the rifts are determined (at least 
in the upper part of the earth's crust) by divergent 
forces and not by convergent ones as is maintained 
in certain hypotheses. This structure, disclosed 
in echo soundings undertaken by the first expe- 
dition of the Campagnes Oceanographiques 
Frangaises, stands out clearly thanks to the 
absence of sedimentation in this desert sea, the 
absence of erosion and at least in two favorable 
spots of basaltic emissions. Such a structure, 
as we know from the laws of mechanics, can 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 4. Basin and swell structures of Africa, after H. Holmes (1944). Note the well marked polygonal pattern of El-Juf, 
Chad and Congo basins. 



result only from forces of tension to the exclusion 
of convergent thrusts. 

It is readily conceivable that the extensive 
faults that gave rise to the rift-valleys yielded a 
passage to the underlying magma, thus engen- 
dering the potent volcanism of the Erythreo- 
African region. And this kratogenic volcanism 
shows characteristics (rectilinear alignment, 
basicity of the lavas, eruptive types, presence of 
permanent basalt or basal toid lakes.) similar to 
those of intra-Pacific volcanism (as far as the 



Andesite line). It would be interesting to explore 
the geography of the volcanoes of the Pacific 
Ocean (subaerial as well as submarine and guyots) 
for a possible polygonal structure. 

Dixey looks on these basin and range systems 
of Africa, the Western U.S.A., Brazil, the Baikal 
(Cf. Dixey, 1956) as the effect of contraction due 
to the cooling of the globe. 

Perhaps it would be wise, in the light of the 
lunar structures, to consider this configuration 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



as the superficial aspect of deep and relatively Dixey, T., 1956, The East African Rift System, 
vast convection cells. London H.M. Stationery Office. 

Cousteau, J.Y. W. Nesteroff and H. Tazieff. 

REFERENCES Coupes transversales de la Mer Rouge. 

Tazieff, H., 1953, Profils en travers du Centre de 

... . . , . ^ in/l c , ,. . TJ . . la Mer Rouge, Contribution d la con- 

Wasmtynski, G. 1946 .Studies ; m Hydrodyna- naissance des grands effondrements 

mics and Structure of Stars and Planets. (note p r6 , iminair * e)> in C ongres Gtol. 

Astrophysics Norvegica. 4, Oslo. /Htori.-Compte-Rendus, Section IV, 

Holmes, A., 1944, Principles of Physical Geology. Fasc. IV, Alger. 



164 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



CRATOGENIC AND OROGENIC VOLCANISM 



H. A. BROUWER 

Stadionweg 90, Amsterdam, Netherlands. 

(Abstract) 



Cratons and orogens are two contrasted tecto- 
nic elements of the earth's crust, which are con- 
nected by transitions in space and time. The 
available energy of the magma and the resistance 
of the crust, which both change continually, 
determine the birth and the lifetime of a volcano. 
Displacements between adjacent parts of the 
crust may be caused by horizontal tension, by 
horizontal compression, and by the action of 
vertical forces. Magma will naturally flow 
toward the place of lowest pressure and volcanic 
activity will mostly go along with crustal tension 
and normal faulting, premising that the faults 
extend downward sufficiently. 

In the cratons the balance of evidende with 
regard to the much debated origin of some con- 
spicuous fault troughs accompanied by volcanic 
activity (e.g., Rhine Valley, East-Africa) is in 
favour of the predominance of crustal tension in 
broad swells, uplifted by more or less vertical 
forces. The location of volcanic activity shows 
dependence upon the form of the uplifted swell. 
Strong and long-lasting volcanic activity may be 
expected in regions of maximal tension. 

The more mobile orogens show a great variety 
of types with regard to their tectonic and volcanic 
evolution. Their history shows successive phases 
of simultaneous or alternate horizontal and 
vertical movements. There may be phases of 
predominant uplift without folding or shortening. 
In the Andean chains of South America the 
folding is not very intensive. A principally 



neritic sedimentation and repeated block-faulting 
were accompanied by great outpourings of 
volcanic products and volcanoes occur on the 
top of the present mountain range. In the Alps a 
wide composite geosyncline was the site of 
magma ascent before the orogenic paroxysm. 
Later strong shortening of the cross-section of 
the original geosyncline and the thickening of 
the curst by the superposition of overthrust sheets 
may have hampered the ascent of magma to the 
surface and volcanoes do not occur on the top 
of the present mountain chain. In a number of 
arcuate orogens there is a striking manifestation 
of diagonal and transverse volcanic lines, while 
more or less longitudinal volcanic lines are often 
prominent in straight orogens. Diagonal volca- 
nic lines are, e.g., found in the northern row of 
Lesser Sunda Islands near Australia. They are 
possibly connected with tangential push and rela- 
tive tension during elongation of the moving 
island arc. This region affords an example of a 
relationship between tectonic evolution and 
extinction of volcanism. Volcanoes are now 
wanting on the southern or Timor row of islands. 
On the northern row they are wanting near the 
place where this row is nearest to the Australian 
continental shelf. Volcanic action was more 
prolonged in proportion as the distance between 
the mobile belt and the Australian craton 
increases. These examples illustrate the influence 
of the varying structural evolution upon the 
carying volcanicity of the mobile belts. 



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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



ON THE IMPORTANCE OF SUBMARINE VOLCANIC FORMATIONS 

INTERCALATED IN THE FOLDED FORMATIONS OF 

THE GREAT OROGENS 

J. AVIAS 

Montpellier, France. 



(Abstract) 



Among the volcanic deposits linked up with the 
final premonitory phases of the folding of a 
geosynclinal series, the eruption and the discharge 
of pyroclastics and andesitic or basaltic lavas, 
mainly under water, and often associated in that 
case with red argillites and radiolarites, are to be 
noticed. During the folding proper these volcanic 
formations are strongly dislocated and accom- 
modated in the upper section of the orogen. 

As with all the other geosynclinal deposits, 
they are subjected to metamorphism, with this 
peculiarity that, being the last of the formations 
formed, they will be often in "reduced cover" 
conditions and will be subjected in general to a 
phase of weak metamorphism only. Stress 
conditions and tension may, however, remain 
intense. 

According to the author's view, based on 
studies and observations in the alpine chain of 
New Caledonia and Corsica, these volcanic 
formations would form deposits rich in magne- 
sium, nickel, etc. The metasomatic concentration 
of these elements would form in a first phase 
chlorites and serpentines, and in a second phase 
peridotites and pyroxenes of ultrabasic rocks. 1 
We would then have a coherent explanation for 
the existence of uitrabasic masses of rocks and 
of the "serpentine belts" which are known in the 
upper part of the alpine mountain ranges. Ac- - 
cording to the author, the spilites, dolerites, 



chlorite-schists, and other associated green rocks, 
would then represent only the "complementary" 
products of a real metamorphic differentiation 
which took place. Moreover some exact observa- 
tions have shown (cf. J. Avias 1955 2 ) that if we 
calculate the composition of the rock which is 
supposed to give birth to the metasomatic rocks 
on one side (containing more magnesium, iron, 
nickel, etc.) and the associated green rocks on the 
other side (containing more SiO 2 , Na, Ca, etc.), 
we obtain the composition of a normal oceanic 
basalt. Apart from the field observations of 
contact and transitional enclaves, which the 
author investigated, this theory explains also the 
fact that "serpentine belts" are developed in 
recent mountain ranges, such as the alpine chains. 
In older chains, such as e.g., the hercynian, the 
corresponding upper part of the orogen has 
disappeared by denudation and only the root of 
the orogen, more or less granitized, remains. 

The above proposed theory throws a new 
light on a set of facts which the classical theories 
were not able to explain, and draws attention to 
the considerable importance which the geoche- 
mical material, represented by the submarine 
volcanic formations of the pre-orogenic period 
in the geosynclinal series, had during the later 
stages in the development of the orogens, 
particularly in the formation of the ultrabasic 
rocks in the orogens. 



1 Under the conditions which correspond with outcrops, these minerals would give birth to classical secondary serpentine. 

2 Colloque International de P6trographie (Nancy, C.N.R.S. LXVI1I): Les ^changes de matieres au cours de la genese 
des roches grenues, (pp. 213-237, 12 figs., 3 tab), Paris 1955). 



166 



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GEOLOGY AND GEOPHYSICS 



THE BLOCK STRUCTURE OF THE CRUST AND ITS BEARING 
ON ORE DEPOSITS AND VULCANICITY 

E. HERBON HILLS 

University of Melbourne, Carlton, Australia. 



THE BLOCK STRUCTURE OF THE CRUST 

The existence in the earth's crust of relatively 
rigid blocks that act as distinct tectonic units 
is a tenet of many theories of earth structure 
although these blocks are conceived by different 
tectonicians to behave in different ways and thus 
to perform different tectonic functions. The 
geosynclinal theory, as developed by Deecke, 
Obrutschev and others from 1910 to 1930 clearly 
introduced the notion of mobile belts and stable 
blocks. These latter, although of continental or 
sub-continental dimensions, were nevertheless, 
at least in part, subdivisions of existing continents 
and thus of somewhat smaller dimensions than 
the continents. The geosynclinal theory itself 
implied no corollary of a permanent distinctive- 
ness of the rigid blocks, but such a notion had 
independently been proposed by the recognition 
of the pre-Cambrian shields and tables, the 
"coigns" of the continents, about and between 
which the mobile belts are to be found. By 
folding and igneous buttressing, old mobile belts 
of geosynclinal type were conceived to be welded, 
according to one school of thought, onto the 
ancient shields. 

It followed naturally from such ideas that the 
folding of geosynclinal deposits should be 
conceived to have been caused in most instances 
by a movement together of the rigid blocks 
on either side the "jaws of a vise" mechanism, 
and where, as is so common, the folding is 
marginal to a continent and facing the ocean, 
Kober's Orogentheorie implied that from a tec- 
tonic point of view the ocean floors might be 
considered as the analogues of these continental 
blocks, and both continental and oceanic types 
of rigid masses were united by him as cratogenes 
(now cratons). Trans-oceanic as well as continen- 
tal orogens were likewise recognized in Kober's 
synthesis, but the oceans will not be discussed 
further in this present account. 

To return to the continents, and setting aside 
for the moment certain alternative hypotheses, 
advances in knowledge of most shield areas 
required the further subdivision of these great 
tectonic units, as more mobile zones especially 



of Palaeozoic geosynclinal sedimentation and 
folding were discovered within them. Thus for 
Bryan, Andrews and Cotton the Australian shield 
virtually disintegrated into a series of smaller 
"blocks", and much the same happened with 
Southeast Asia, Siberia and Africa. In no case, 
sofar as I am aware, was any structural basis for 
the existence of these smaller blocks proposed. 
Their margins were accidents unrelated to struc- 
ture, and in Bucher's theory, concerning the 
origin of mobile belts by regional tension due to 
expansion of the body of the earth, it is clear 
that the pattern, if any, is a fracture pattern 
dictated by stress-distribution in a more or less 
uniform brittle crust, and Wegener's Drift Theory 
has, I suppose, much the same attribute in rela- 
tion to the outline and size of the fragements 
of Pangea, the Urkontinent, which are supposed 
to have drifted in late Mesozoic and Tertiary 
times to their present positions. 

At the same time as this group of theories 
involving rigid masses was being promulgated, 
other ideas were also expressed which were 
fundamentally different. Argand's notion of 
pits de fond and pits de converture involves, so 
far as I can see, no fundamental distinction 
between rigid blocks and mobile belts, and does 
not account for the localization of these belts. 
The theory has, however, not been widely ac- 
cepted although the assumption of a plastic 
softening of a crystalline basement has been 
assumed especially in relation to Saxonian Bruch- 
fallen. Theories that postulate crustal down- 
buckling have, especially of late years, relied 
largely on convention currents in the mantle to 
develop tectogenes, and presumably the pattern 
of tectogenes is therefore related to the outlines 
of the convection cells. The cells in Arthur 
Holmes' hypothesis are actually determined by the 
blanketing effect of pre-existing continental 
blocks on the escape of radio-genie heat, and the 
action of the currents is to dismember these 
blocks. This theory is difficult of application to 
the origination of pre-Cambrian shields and 
blocks, and has also not gained much support, 
nor indeed do Holmes' later writings themselves 
on topics such as the structure of Africa make 
reference to it. 

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PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



This brief review indicates that from one lineage 
of geological thought, block tectonics emerged 
from the geosynclinal theory, but did not progress 
far along this line in relation to the structure of 
blocks or the pattern of mobile belts. The 
pattern of folded zones has been a matter that 
certainly has received much attention in a de- 
scriptive way from the time of Suess, but perhaps 
it might be truly said that the folded belts, how- 
ever important they may be, have unduly over- 
shadowed the significance and interest of the other 
lineaments of the globe, to such an extent that 
workers on lineaments (other than orogens) 
have been regarded as more than a little unscien- 
tific and subject to hallucinations 1 . As one who 
has frankly been interested in the major lines of 
a continent that completely lacks mountain 
chains of the Alpine Revolution, I would venture 
to say that lineament tectonicians have given 
greater thought to the precise details of geologi- 
cal lines than have the alpinists; that the Jura 
arcs are, for instance, better represented as a 
series of linked lineaments than as flowing curves, 
and that, broadly speaking, tectonic geology has 
for many years experienced a serious lacuna due 
to overemphasis of orogenic-type structures. 

Lineament tectonics, which, as we shall see, 
links with block tectonics at a later stage, virtually 
commenced with W.H. Hobbs, it has had 
few notable contributors over several decades, 
but received a great stimulus from the work 
of Hans Cloos ever eclectic and global in his 
thinking, and also from the more detailed analyses 
of European structures by Sonder. Cloos' 
theory of basement blocks included an analysis 
of Alpine tectonics which was the more valuable 
since others working independently on somewhat 
similar lines at the same time were more concerned 
with shield areas. His notion reduces the strate- 
gic plan of the Alps to a series of almost accidental 
tectical exercises, to the slipping and sliding of 
relatively small basement blocks, in contrast to 
the broad frontal movement previously envisaged 
in the action of the traineau ecraseur by 
which Africa overrides Europe. According to 
Cloos, the basement blocks are ancient units, 
relatively resistant and rigid, between which are 
weak zones that in places become the sites of 
geosynclines, and elsewhere are represented as 
fault or warp zones, very like the lineaments of 
Hobbs. 

Those others who, about this time, were 
working on related topics each had a slightly 



different and independent viewpoint. Vening 
Meinesz on geophysical grounds and considering 
also the trends of coastlines and oceanic features 
as corroborative evidence, suggested that many 
major lineaments are elements of a global 
network of shears, the pattern of which he calcu- 
lated (on one assumption) according to a polar 
shift over 70 of latitude along the meridian of 
90 longitude. The actual lineaments included 
in the study are of a variety of different geological 
types, some coastal flexures, other great faults, 
others volcanic lineaments such as the Hawaiian 
Islands. However, since so many were found to 
be of pre-Cambrian age, Vening Meinesz con- 
cluded that the global shear pattern was formed 
very early and that later movements have often 
taken place on the old trends. 

A similar conclusions began independently to 
grow out of work in Africa, chiefly in the Rift 
Valleys, and in Australia on the Shield, but like 
so many geological notions, a similar idea has 
often been expressed by individuals working in 
every continent, and later work has very largely 
tended to emphasize that resurgent tectonics, 
as I have termed it, is a geological principle. 
My own analysis of Australia has led me to recog- 
nize the existence of both a systematic network 
of lineaments including some that are over 1000 
miles long, and of resurgent tectonics. It has 
also indicated that certain lineaments are the 
boundaries of earth-blocks that have acted as 
nuclei or core-regions, like Cloos' basement 
blocks, since late pre-Cambrian time. 

Quite recently, Moodie and Hill have made the 
suggestion that wrench fault tectonics governs 
many if not all of the main fault lineaments of 
the world. They have extended their ideas from 
known wrench faults such as the Great Glen 
Fault of Scotland, the San Andreas fault, and the 
Alpine Fault of New Zealand, to other great 
fault systems where the evidence for lateral dis- 
placement is not so certain and where there is 
likewise very notable vertical displacement. 
Their work stimulates anew an interest in linea- 
ment tectonics, but perhaps enough has been 
said to indicate some of the major issues involved. 

ORE ZONES AND THE INNER 
STRUCTURE OF BASEMENT BLOCKS 

In 1946, I made an analysis of the tectonics 
of Australia from which it appears that the shield 
area is itself subdivided, as had been postulated 



1 Sec for example the critical remarks of Bucher, in the Crust of the Earth: Special Paper Geol. Soc. Amer., No. 62, 1955, 
pp. 343-68, "Deformation in Orogenic Belts". 

168 



by earlier Australian authors notably Andrews, 
Cotton and Bryan. My own analysis went 
further, however, in several ways. Firstly, it 
indicated that the smaller nuclei within the shield 
are "framed" by sweeping tectonic lines, some of 
which represent geosynclines ; secondly it sug- 
gested that the nuclei or cores themselves pos- 
sessed a tendency to concentric fold lineaments 
in the oldest pre-Cambrian; thirdly it indicated 
continued rejuvenation of the frames or weak 
zones, and equally continued cratonic charac- 
teristics for the nuclei; fourthly it suggested 
that a network of major fractures, more or less 
orthogonal, is represented in the Shield, i.e. for 
at least two thirds of the Australian Continent. 
These fractures are lower Palaeozoic, but are 
governed by older pre-Cambrian lineaments. 
Later, I was able to show that the major structural 
network for Australia fits that proposed by 
Vening Meinesz almost precisely a conclusion 
that I had previously myself denied. This corres- 
pondence is seen particularly in what I have called 
megalineaments and what Sonder calls linears 
lines that may be traced across the continent for 
distances of the order of 1,000 miles, and it is of 
interest to note that, as is also recognized by 
Sonder in his notion of equidistance of linears, 
these megalineaments are, indeed, spaced at 
regular intervals of about 4-500 miles (and, by 
chance, approximate to the arbitrary lines of 
shear drawn by V. Meinesz). 

PRE-CAMBRIAN NUCLEI AND 
GEOSYNCL1NAL FRAMES 

In my first analysis of the Australian shield it 
was pointed out that the nuclei of the shield arc 
bounded by zones of sweeping geological trends 
which are structurally weak and correspond in 
part with younger geosynclines. Since that time 
it has been demonstrated particularly in researches 
by the Commonwealth Bureau of Mineral Re- 
sources, Geology and Geophysics, as well as by 
the work of company geologists, that the zones 
marginal to the Sturtian Nucleus of the Northern 
Territory correspond with Lower Proterozoic 
geosynclines. What I have seen of rocks older 
than LIpper Proterozoic in many parts of Aus- 
tralia indicates that the extent and intensity of 
metamorphism of these old rocks has been greatly 
over-stated, chiefly because the earlier workers 
were especially concerned with mining fields such as 
Broken Hill, where very extensive metamorphism 
is found. As surveys have been extended into less 
highly mineralized belts the surprising fact emerges 
that rocks at least as old as the Lower Proterozoic 



VOLUMEJL2 GEOLOGY AND GEOPHYSICS 

(of the order of 1250 million years) are very little 
metamorphosed, excepting locally. It has thus 
been possible to map belts of sedimentation, to 
effect stratigraphic correlation within geosyn- 
clinal zones, and to provide an astonishingly 
clear picture of such zones, which, with their 
Collenia reefs and detrital sediments, afford a 
very clear analogy with younger intracratonic 
geosynclinal zones. This is now best known 
from the Pine Creek geosyncline. On the eastern 
margin of the Sturtian Nucleus the Mount Isa 
pre-Cambrian belt also exhibits features of geo- 
synclinal deposition especially in the north, but 
as the belt is traced southwards, increasing 
metamorphism produces, in places, Archaean- 
type lithology. At Broken Hill, an analogous 
gradation from Archaean-type gneisses in the 
vicinity of the mining centre, to much less strongly 
metamorphosed rocks a few miles distant has 
been known for several years, and is confirmed 
by later mapping. Recent work by Edwards on 
the amphibolites of Broken Hill shows that certain 
of these rocks are transformed limestones. 
Thus the whole regime in this district also begins 
to suggest geosynclinal deposition, the age being 
generally regarded as Archaean. 

For our present consideration of the relation- 
ship of ore deposition to block structures in the 
crust, it can be said that what is now, I believe, 
emerging for Australia is a subdivision of the 
Australian shield into ancient, truly Archaean 
nuclei, framed with younger geosynclinal zones 
from the Lower Proterozoic, and, in the Shield, 
a partial immobilization of these as a result of 
orogeny, igneous action and ore genesis of pre- 
Upper Proterozoic date. Within the shield, 
then, ore zones, especially such as would be 
commonly regarded as hydrothermal in origin 
and somewhat closely restricted to the locus of 
their mobilization, correspond with the framing 
zones, and likewise with the Lower Proterozoic 
geosynclines, and perhaps also with older geo- 
synclines still to be mapped. This idea is clearly 
set out by Noakes in a recent review for the 
Northern Territory. 

The broad picture may be affected by two 
further considerations. Firstly, ore deposits 
related genetically to dyke rocks younger than 
the last geosynclinal phase of ore genesis might 
exist. This is the case, for instance, with lead 
ores related to Lower Palaeozoic dyke rocks in 
the Northampton district, Western Australia. 
But, so far as is known, dykes of such an age, in 
the shield area, are limited to rather restricted 
zones of fracturing near the edge of the shield. 

169 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Secondly, highly soluble elements such as ura- 
nium and lead may be remobilizcd by quite small 
rises of temperature under hydrothermal condi- 
tions or even by weathering. Thus such elements 
may be expected to occur rather widely dissemi- 
nated and also in quite young rocks. Only rarely, 
as for example in the case that low concentrations 
are sufficient to afford a usable ore-deposit, are 
such effects likely to be economically important, 
as is true for uranium. The lead deposits in 
Tertiary limestones along the Red Sea in Egypt 
do, however, indicate that such effects may be 
significant for this element also. 

The study of the distribution of ore deposits 
is, in fact, much influenced by the grade of con- 
centration necessary to constitute an ore. This 
is well shown by the records of gold, which is 
sought in quantities so low as to be measured 
in parts per million, and consequently is one of 
the most widely recorded of minerals. 

The Palaeozoic and later hydrothermal ore 
deposits of Australia are very clearly related to 
geosynclinal zones, as is almost universally true. 
What interests us for the moment is, in how far 
do these young geosynclines lie marginal to 
pre-Cambrian nuclei, either hidden or exposed, 
or, on the other hand, in how far do they lie in 
newly created zones of crustal mobility. 

To solve this is not, at present, possible, but 
at least it is clear that the Australian geosyn- 
clines of later date follow in places trends of 
pre-Cambrian age nearly (e.g. Westralian Geosyn- 
cline, Tasman Geosyncline in north-Queensland) 
and that two dominant orthogonal networks, 
the one according to Vening Meinesz, the other 
a bisecting network (the importance of which was 
also recognized by that author) account for most 
of the major features, young and old, of Aus- 
tralia. 

VULCANICITY 

In Australia, Cainozoic vulcanicity is limited 
to the Eastern Highlands and nearby regions, to 
the south-west of Western Australia, and to the 
Fitzroy Valley in the northwest of Western 
Australia, where a series of remarkable leucite 
plugs has been discovered by Wade and Prider. 
The major structural lines of the Eastern Highlands 
are very clearly fractures indeed it is a great 
difficulty in engineering geology to find sites over 
100 yards square that are not traversed by faults 
or shear zones, and "jointing" is ubiquitous. It 
is in this millieu that the Cainozoic vulcanicity 
occurs. 

170 



A map showing the distribution of the major 
volcanic centres reveals very clearly a relation- 
ship between several of these and known mega- 
lineaments, whereby the volcanic centres occur 
at the intersection of the major fractures. This 
is particularly notable for the great alkaline com- 
plexes of New South Wales, two of which lie on 
the major boundary fault of the Highlands, where 
this is intersected by NNW lineaments; a third 
lies on a NNW lineament projected into the 
Highlands. 

Relationships such as these have so often been 
described for volcanic phenomena that the interest 
in relation to Australia is rather local than gener- 
al, but in another way the results are of interest 
in that they afford supporting evidence for the 
existence of the major fractures delineated in 
Eastern Australia, where the dyke intrusions of 
Cainozoic age also give clear evidence of strong 
NW-SE, E-W, and NNE fractures in the Eastern 
Highlands. 

Moreover a further significant point emerges, 
which is that these Cainozoic dykes are limited 
in their distribution to a zone that has been geo- 
synclinal since the Cambrian the Tasman Geo- 
synclinal Zone. Thus, although the vulcanicity 
represents an effect of fracturing, it is clearly 
influenced by much more ancient geotectonic 
structures, and more than that, all Palaeozoic 
and Mesozoic vulcanicity in Australia, after the 
Lower Cambrian which is related to Upper 
Proterozoic tectonics, is likewise strictly limited, 
and in fact is known only in the mobile belt of 
the east the Tasman Geosyncline. 

Thus, despite the obvious youthfulness of the 
highland uplifts, faulting and vulcanicity of 
Eastern Australia, which suggests that a new 
fracture pattern is involved, we are forced to 
recognize that the belt so affected has been mobile 
throughout Palaeozoic and later time. Such a 
* result which could equally apply to the Wes- 
tralian Geosyncline except that this is affected 
by vulcanicity only to a very minor degree in 
Cainozoic times only shows either a persistent 
structural inhomogeneity that has determined 
where mobility will be in evidence, or a continu- 
ing continent-wide stress and strain pattern that 
has, in its fundamentals, remained the same 
since the Upper Proterozoic. The former seems 
the more probable explanation. 

GLOBAL TECTONIC 

This is no place to review such a topic on a 
global scale, but I will venture one or two 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



comments. The great scarp that flanks the 
Dead Sea Rift on the east is a major fault which 
appears to have been already in existence in the 
Cambrian. In this, and in its persistent down- 
throw on one flank, it resembles the Darling 
Scarp which flanks the Westralian Geosyncline. 
The Dead Sea Rift is, of course, only one element 
of the great rift system of the Africo-Arabian 
block, and it is now becoming clear that the age 
of these faults is much greater than was formerly 
believed; they are known to be at least Jurassic 
and probably older still, even Pre-Cambrian. 

Evidence for the antiquity of major crustal 
structures is best got in cratonic areas because of 
their relative geological simplicity. But we know 
that the European Alpine tectonics can be traced 
back at least as far as the Middle Carboniferous, 
a fact which although well known is surely not 
sufficiently emphasized, for it means that the 
stress pattern, or at least the strain pattern and 
dynamics of the Alps are by no means only part 
of the Alpine Revolution of the Oligocene, but 
vastly older. 

WRENCH FAULT TECTONICS 

Like all geological notions the idea of major 
transcurrcnt or wrench faulting has its roots far 
back, but of recent years has come into promi- 
nence through the work of Sonder in Europe, 
Kennedy for the Great Glen Fault, Hill and 
Dibble for the San Andreas, and many other 
workers. It is inherent in general theories of 
folding such as those of H. Cloos. While the 
notion of basement blocks lends itself readily to 
lateral displacements, it is true it is much more 
the physics of the process that is fundamental, 
for movements of 60, or even 300 miles have been 
postulated since Jurassic times in New Zealand 
and in California. A global stress pattern is a 
sine qua non for movements such as this, a pattern 
not young, and, if not yet known to be entirely 
old, then at least geologically middle aged. 



While there is some evidence for wrench fault- 
ing in the megalineaments of Australia it cannot 
be said that the obvious evidence for great dis- 
placements is strong. Moody and Hill's linea- 
ments can account geometrically for all the lines 
of the world; it will be a major task of geology to 
prove or disprove their proposition that most if 
not all lineaments are wrench faults. 

That there is still the opportunity, despite a 
plethora of points of view, for some new way of 
regarding global tectonics is shown by Brock's 
work based on Africa. This, however, is so new 
to me that 1 must confess I have not yet assimi- 
lated the notions in it. 

To conclude, we may say that several lines of 
geological work, on lineament tectonics, geo- 
physics and pre-Cambrian stratigraphy, have 
begun to converge to reveal the existence of a 
block structure in the crust that major geosyn- 
clines, igneous action and related or genesis are 
controlled by such blocks and their framework; 
and that this is revealed as far back as the Lower 
Proterozoic. A fundamental issue of a gep- 
chemical and practical nature remains. That is, 
are there major and persistent geochemical 
differences between the different ore zones, 
recognizable throughout geological time? Or 
are such differences as do exist related to the 
type and intensity or ore-generating processes at 
any time modified by later erosion to expose the 
depth zones in different ways ? 

An answer may be indicated from a mobile 
belt that has been active at many times since the 
Cambrian the Tasman Geosynclinal Zones of 
eastern Australia. Here the evidence, which has 
been admirably summarized in a recent work, 
points clearly to the omnipresence of elements, 
and to the control of ore-deposition at any time 
by the geochemistry of the processes of differen- 
tiation and ore deposition within a wide range 
of structural and lithological environments. 



171 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



CONTINENTAL RIFTING AND IGNEOUS ACTIVITIES IN 
THE NEOGENE MARGINAL GEOSYNCLINES OF TAIWAN 

V. C. JUAN 

National Taiwan University, Taipei, Taiwan, Republic of China. 



INTRODUCTION 

The concept of geosynclines, first set forth by 
Dana in 1873, has been developed into a great 
unifying principle in geologic science. Geosyn- 
clines, as noted, are troughs of long continued 
subsidence upon accumulation of sediments. 
Great thickness of sediments, generally considered 
as one of the important characters of geosyn- 
clines, is the result of time as well as rate of depres- 
sion and deposition. However, the magnitude of 
subsidence and time limits of a geosyncline are 
ill defined. Insofar as structure is concerned, a 
geosyncline is a basin, trough, or furrow whose, 
base subsided deeply under extensive surficial 
rocks during their deposition and accumulation. 

Based on the form, origin of contained rocks 
and the associated tectonic environments, the 
geosynclines are classified by Kay (1947) into 
orthogeosynclines and geosynclines within the 
hedreocraton. The orthogeosynclines designated 
by Stille (1936) are linear or arcuate mobile belt 
bordering the comparatively stable continents 
or craton. An ancient craton which had persist- 
ing influence on continental development and 
has close correlation with present structures is a 
hedreocraton. The orthogeosynclines are sub- 
divided into eugeosynclines and miogeosynclines 
on a volcanic basis of distinction. An eugeosyn- 
cline is a structure that has subsided deeply in a 
belt having active volcanism, while a miogeosyn- 
cline lies in a non-volcanic belt. The area of 
craton separating the geosynclines are relatively 
more stable. They commonly have been called 
geanticlines, uplifts, tectonic lands or platforms. 

The concept of geosyncline has been extensively 
developed and greatly expanded into a geosyn- 
clinal theory (Knopf, 1948) through immense 
number of detailed studies. A remarkable store 
of facts and interpretations is on hand concerning 
the geosynclinal sedimentation, the igneous 
activities during the evolution and revolution of 
the geosyncline, orogenic phases that comprise the 
revolution, regional metamorphism and metal- 
logenetic epochs related to intrusives during the 
successive orogenies. Thus, any site of deposition 
of any geologic age that deems to be in the nature 

172 



of a geosyncline can be tested thoroughly with 
the above phases. 

The Neogene stratigraphy in Taiwan shows that 
there were thick sediments in belts on each side of 
the Central Mountain. These belts have been 
depressed into downfolds and are considered 
to be geosynclines in being linear and in having 
few volcanic rocks. It is the aim of this paper 
to examine critically the elements of these geosyn- 
clines, with emphasis on the role of igneous acti- 
vity. The relation of geosyncline to volcanism 
will be discussed with stresses on the great out- 
pouring of lava in the form of fissure eruption 
through the process of continental rifting at the 
initial stage of geosynclinal evolution. 

NEOGENE GEOSYNCLINES OF 
TAIWAN AS MARGINAL GEOSYNCLINES 

The origin of the island of Taiwan has been 
a subject of hypotheses and theories. The hypo- 
thesis of a coastal range of the Asiatic continent 
was expressed by Juan (1956) in contrast to the 
common modern origin of an island arc. He 
discussed the problem from various angles such 
as the structural correlation between continent 
and the island, the ill comparison with Riukiu arc 
and Philippine Archipelago, the origin of Formosa 
Channel, the cause of present simple shore 
line and the submarine topography around the 
island, and concluded that the island of Taiwan 
has long been in exislance and is actually a part 
" of the old land of Fukien province. 

The Asiatic continent in the Palaeozoic time 
had an interior platform, the hedreocraton, and 
the continent was bordered by belts of depres- 
sion, the miogeosynclines, well shown in the 
paleogeographical maps prepared by Grabau 
(1928, pt. II. pi. 10). There have been various 
interpretations suggested in the past for the 
paleogeography of continental borders. In the 
course of his study of the North American conti- 
nent, Stille preceived the existance of a Pacific plio- 
magmatic belt and a Rocky Mountain magmatic 
belt on the continental border of western North 
America. Kay differentiated these marginal 
geosynclines as eugeosynclines and miogeosyn- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



STRUCTURAL MAP OF NEOCENE GEOSYNCLINES OF TAIWAN 
SHOWING STRUCTURAL ZONES AND THEIR RELATION TO RIFTING 
PREPARED BY VC JUAN IQ57 



TLO Moo-t'alm^o T,r+o., Lan 

^LY Palaeogene Tc-on, Land 

EGA Mobile 7onc Nroq<?np fuqpo. 

EGB D<?cp 7 one NK^VK LiXJP^ 

MGA Mob.lc /Op Ncoqn* Mn^o- 

MGB ~~ Deep none Ncrxjen* M.oqco 

CP Pler.tocenc Lraton 

Wc<il Cod-,* Fault 

Alishn Foull 

@ Vusha 



// 

// 

^? 7 

/ 



0^* 

*&> 



CP -V Penghu Island- 



B-,. 

A .. 



LEGEND 



Lower Miocent 



Mid- Miorunc UHr* 
basics Gobbojs* Serparfint 

Pl.o-Plei^occne 
Andvsitc f low> 




Fig. 1. 



173 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



clines, divisions of compound orthogeosynclines 
and considered that regions beyond the miogeo- 
syncline were deep- sinking belts of sediments 
and marine volcanic rocks. These regions are in 
unit geosynclines lying between and among 
tectonic swells or grading craton-ward into mio- 
geosynclinal belts. 

That the island of Taiwan can not be com- 
pared with any existing island arcs is evidenced 
by the significant fact that no satisfactory account 
has been given for the reverse direction of the 
arc which has a convexity facing the continent. 
No less significant is the fact that Taiwan is not 
situated on the rim of the continental shelf areas, 
the rightful locations generally agreed upon for 
the formation of island arcs. Due to the process 
of continental rifting, which is very important 
in connection with marginal geosynclines, con- 
tinental shelves are absent in this part of the 
Asiatic landmass. 

Viewed as a part of the Asiatic continent, the 
island has been a belt of marginal geosynclines 
and that the major structural units constituting 
the framework of the island are the various com- 
ponents of a composite orthogeosynclinc. These 
involve (1) volcanic Ncogene eugeosyncline of 
the East Coastal Range; (2) a tectonic land 
forming the Central Mountain in the middle; 
and (3) non-volcanic Neogenc miogeosyncline 
occupying the western part of the island. In 
addition, an intracratonal gcosyncline exogeo- 
syncline at the site of Taiwan Strait is in its 
embroyic stage of formation. 

The geologic history of this orthogeosynchne 
can be traced back as far as the Palaeozoic. The 
metamorphic complex (TLO) including schist 
and gneisses represents the fossil sedimentation 
in troughs filled up one after another in the 
periods of the Palaeozoic era. The regional meta- 
morphism that it suffered and the subsequent 
intrusion of acidic rocks indicate the closing 
phase of the ancient geosynclinal evolution. A 
great cordillera was thus formed nearly at the 
present site of the island, a geologic expression 
of the so-called Palaeo-Taiwanian revolution. 

The late Mesozoic (Upper Jurassic and Creta- 
ceous) and early Tertiary transgressions which 
invaded the geosynclinal depression broadly 
downwarped on the flanks of the cordillera 
were not very extensive, their deposits occupying 
only limited areas (TLY) west of the Central 
Mountain. Regional metamorphism of much 
less degree set in at the end of Eocene, represent- 
ing the Neo-Taiwanian revolution. 

174 



The fossil sedimentations of both the Meso- 
Palaeozoic and the Paleogene geosynclines appear 
now as tightly compressed assemblages of a 
tectonic land in the midst of Neogene geosyn- 
clines. 

Throughout the period of younger Tertiary, 
a new ortho-geosyncline was in existance and 
the island incorporated a new structural unit to 
its framework. This was the Neogene orthogeo- 
synclinc completely surrounded the old tectonic 
land at the southern tip and occupied both eastern 
and the western parts of the island, as we see it 
now. Considered as a marginal geosyncline at the 
border of the Asiatic continent, it consists of two 
components, an outer eugeosyncline situated at 
the present site of the East Coastal Range and an 
inner mio-geosyncline located west of the Central 
Mountain. Thus they were separated by a welt 
of pre-lMeogene rocks along the greater part of 
their length but merged together at the peninsula 
of Hengchun ; and they were not pairs of con- 
tinuously expanding troughs, but linear arcuate 
depressions along the border of the continent. 

The sediments in the East Coastal Range with 
and estimated thickness of 6,000 meters (Hsu, 
1956) are typically eugeosynclinal. The earliest 
phase occurring at Lower Miocene time was 
andesitic lava, which was followed by accumula- 
tion of volcanic detritus and fragmental rocks. 
After the formation of lava agglomerate a trans- 
gression set in at the consequence of downwarp- 
ing and marine environment prevailed and the 
volcanic materials that formed the argillites were 
adequately sorted and well stratified Although 
terrigeneous and volcanic detrital sediments 
were abundant, great areas were covered with 
carbonatite, commonly calcitites, of 5 to 25 meters. 
From this bathymetric extreme, rocks in the eugeo- 
syncline passed on one hand in the northeast to 
lava, tuff and coarser fragmental rocks and the 
derivatives of weathered volcanic materials, and 
on the other in the southwest into terrigeneous 
sediments eroded from tectonic lands. Thus 
about 1,400 m. of conglomerate accumulated 
near Taitung close to the margin of the sea. 
The presence of metamorphic pebbles suggests 
vigorous erosion on the exposed old rocks. 

In the middle and upper Miocene time, the 
water depths in the geosyncline tended to increase 
rapidly, a great sequence of argillite, graywacke 
and conglomerate reaching a thickness of 2,700 m. 
were deposited. Since lands were immature, 
sediments were poorly sorted, graded bedding 
and slump structures of contemporaneous defor- 
mation are generally found. The predominance 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



DIAGRAMMATIC SKETCH SHOWING THE STRUCTURAL UNITS OF TAIWAN 



PLH 



(Possible Pleistocene 
G cosy nc I me) 




of a graywacke suite indicates that tectonic uplift 
interrupted subsidence, though the sum of 
movement was downward; and that the belt was 
commonly quite mobile with steep submarine 
slopes and high relief land. The absence of 
orthoquartzite and arkpse must be interpreted 
as reflecting the tectonic mobility that did not 
permit sorting of rock constituents exposed. 

Contemporaneous with the graywacke sequence 
in the northern part of the geosyncline, sedimen- 
tation of massive clayey beds containing exotic 
blocks of various rocks under condition of mass 
mud-flow took place in the southwestern part. 
Such lithologies characterized the deeper part 
of a physiographic trough with gentle slopes that 
the mode of transportation of detritus was more 
of creeping than rolling and promixal to the 
active recurrent uplifting along the East Longitu- 
dinal Fault that dates back as far as the beginning 
of the Pliocene. 

The third cycle of sedimentation in this geosyn- 
cline from upper Miocene to Pliocene was typified 
by alternating beds of graywacke and argillite 
topped with impure limestone of shallow water 
origin. 

This eugeosyncline extended southward far 
beyond Taitung and merged into the miogeosyn- 
cline of western Taiwan at Hengchun; where 
spilitic basalt, which is closely related with eugeo- 
synclinal vplcanism, has been found (Wang, 1951). 
The deposits in the eugeosynclinal belt were not 
continuous into the miogeosynclinal belt. The 



sediments in the two belts, though not mutually 
exclusive, are contrasted sharply. These persist- 
ing contrast in facies reflects constant differences 
in sedimentation condition through the periods 
of Miocene to Pliocene. Curiously, the zone of 
juncture of the two belts, as invariably verified 
by Kay (1951) the world over, is one of great 
deformation; the extensive East Longitudinal 
Thrust Fault brought the outer eugeosynclinal 
side as an allochthone over the passage into 
the inner, miogeosynclinal autochthone. 

The sediments in the miogeosyncline of western 
Taiwan appear in a quite different situation. 
The intermediate position of miogeosyncline 
between eugeosyncline and hedreocraton had 
great influences on deposition which was effected 
by the peripheral mobile tectonic land and 
meanwhile received well sorted detritus from 
relatively stable hedreocraton. Thus argillite 
and carbonatite, the formation of which were 
encouraged by more uniform and gradual sub- 
sidence, are relatively abundant. Volcanic rocks 
are rarely present in the northern part and 
virtually absent in the greater part of the geosyn- 
cline. The great sequence of sediments, which 
has an estimated thickness of more than 7,000 
meters, represent also three cycles of sedimentation. 
Such rhythmic deposition began with weak volca- 
nism as evidenced by the Kungkuan pyroclastics in 
the first cycle of Lower Miocene age and succeeded 
with a long period of accumulation of argillite and 
low grade graywacke (Wang, 1954) and sandstones 

175 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



belonging to the orthoquartzite clan and followed 
by organic deposition of coal and carbonatite. 
This has been termed as foreland facies (Pettijohn, 
1957, p. 633-636) in opposition to the geosyn- 
clinal facies which is typical in the eugeosyncline. 
Although the distinction of facies depends prima- 
rily on the stability of source areas and the avail- 
ability of transport to the sedimentation trough, 
the foreland facies, a product of accumulation 
of shallow seas, has its greatest thickness and 
volume in the miogeosyncline. However, locally 
coarse rudites have been found in the late cycle 
of sedimentation of the Late Miocene to Pliocene, 
but owing to the shifting of direction of trangres- 
sion in different cycles of sedimentation and the 
orogenic movement recurrent before the time of 
Pliocene, distinctions between distal, axial, and 
proximal facies can not clearly be made, though 
a foreland facies has been noted in association 
with a geosynclinal facies in the same geosyn- 
cline at different times and places. 

IGNEOUS ACTIVITIES IN 
THE MARGINAL GEOSYNCL1NES 

Daly (1912) was the first one who had the idea 
that the geosynclinal evolution and the orogenic 
revolution controlled by it are marked by a 
definite cycle of igneous activity. This hypothesis 
was later elaborated and extended by both 
Kossmat (1921) and Scheumann (1924) into 
prototectonic, syntectonic and apotectonic stages 
characterized by submarine basalts and associated 
"ophiolites" ; granitic intrusions; and stocks 
and batholiths of massive granite respectively. 
These ideas had become a full-fledged theory by 
1932 (Knopf, p. 568) when they were applied to 
explain the igneous activity during the Variscan 
period in Saxony and thus offered a possibility 
of shedding some light on a major problem of 
geology in other regions. 

In the eugeosyncline of the East Coastal Range, 
several series of igneous rocks have been noted. 
Volcanism was active at the begining of the evolu- 
tion of the geosyncline early in Miocene time. 
800 meters of andesites were erupted in the earliest 
time, but later 1 ,500 m. of andesitic pyroclastics 
were deposited. As the deepening of the sedimen- 
tary trough continued as a consequence of the 
subsequent accumulation of nearly 1 ,400 meters 
of sediments, the Middle Miocene Lichi formation 
(Hsu, 1956), plutonic intrusions of the type of 
serpentinized peridotite and gabbro came in 
during the first great deformation that folded 
the sediments in the geosyncline. Somewhat 
later several chonoliths of dolerite and basaltic 

176 



glassy rocks (Juan et al, 1953) intruded probably 
at the height of the tectonic revolution between 
Middle and Upper Miocene time. However, 
true "geosynclinal basalts" have not been found, 
a small submarine body of spilite (albite basalt) 
was extruded before the geosyncline was extin- 
guished at the end of the Pliocene. 

In the miogeosyncline of western Taiwan, 
corresponding igneous activities in the different 
stages of evolution of the geosyncline have also 
been found, though somewhat different in petro- 
graphy and strikingly contrast in magnitude and 
intensity. The earliest phase was the volcanism of 
early Miocene, well represented by the Kungkuan 
tuff beds in the northern part of the island. The 
thickest accumulation is reported about230meters, 
where four beds of tuff have been observed. 
Except for the lowest bed which is represented by 
volcanic agglomerate and breccia, the upper three 
beds are well bedded tuff intercalated with marine 
shale and siliceous limestone. When the floor of 
the geosyncline, upon receiving thick accumula- 
tion of cyclic depositions of marine strata and 
coal beds brought about by alternate transgres- 
sions and regressions, sank into considerable 
depth at the end of Middle Miocene, igneous 
activity of the second phase appeared as intrusions 
of alkaline basalt, analcite dolerite and basanite 
(Yen, 1949 a & b). The unstable nature of the 
floor of the deepening geosyncline, as indicated 
by the greatly differing rate of subsidence, more 
rapid in the southern portion, perhaps made 
possible the rise of the molten magma. However, 
the problem is much more complex petrographi- 
cally, for it involves a change of nature of magma 
from subalkalic to alkalic between Lower Miocene 
to Middle Miocene. The last phase of igneous 
activity with a corresponding age of Pliocene 
was formerly held as nonexistant in this province. 
But careful structural research seems to have 
validated the thought that the Tatun volcanism of 
mainly andesite flows may be taken to account 
for this epitectonic stage. Structurally, the group 
of Tatun volcanoes, though situated at the 
northern tip of the island, lies well within the 
boundary of the province of the miogeosyncline. 
The volcanoes are evidently localized on open 
spots along faults and their eruptions were not 
vigorous nor explosive but characterized by a slow 
escape of emanations, thus resulting in hydrother- 
mal concentration of ore-forming solutions. Sul- 
phur deposits occur within the andesites and gold- 
copper ores in the dacite bodies. 

From the evidences for the Neogene geosyn- 
clines in Taiwan that have been briefly sketched 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



here, it can be seen that a series of happenings 
seem to have only partially confirmed to the 
systematic cycle of igneous activity outlines by 
Kossmat. According to Kossmat, the submarine 
eruption of basalts and other ophiolites began 
when the geosyncline was nearly filled. In the 
Neogene miogeosynclines of Taiwan, like the 
Appalachian geosyncline of Palaeozoic age 
south of New York, no extrusion of basalt has 
been found, but basalt pyroclastics were erupted 
and in the eugeosyncline, the highly differentiated 
lavas of andesite, similar to the Tasman geo- 
syncline of Queensland (Sussmilch, 1935) were 
extruded at the inception of the geosyncline early 
in Miocene time. Thus true geosynclinal 
basalts witnessed by Tyrrell (1937) in the Cale- 
donian geosyncline are not present here at the 
stage of geosynclinal sedimentation. Basaltic 
rocks such as gabbro, serpentinized peridotite, do- 
lerite and basalitc glassy rocks occurred in the 
eugeosyncline at a time when the geosyncline was 
almost filled. However, since these rocks have 
suffered no metamorphism and thereby become 
altered into well known green rocks collectively 
called "ophiolites\ they are not considered to be 
the prototectonic phase but concomitant with the 
folding at the syntectonic phase of the crustal 
revolution as illustrated by Hess (1940) in his 
study on the Appalachian peridotite belt. 

In the Neogene geosynclines of Taiwan, no 
granite is known to have been emplaced during 
the syntectonic stages. It is doubtful whether 
such granite intrusions have ever occurred in 
depth. For the ultrabasic and basic, the latter 
ones have been named Taiwanite by Juan (1953) 
as representing a kind of parental magma type, 
occurred instead. This fact invalidates the theory 
that the granite magma was generated at the 
stage of folding by disolving the sialic roots of 
the folds that had subsided deeply into the sima 
in restoring equilibrium, and that the Intrusion of 
granite is a mark of isostatic subsidence. It 
seems that the intrusions of the basic rocks at this 
stage were guided rather by rifting that initiated 
the growth of the geosyncline near the contact of 
the Asiatic continent and the Pacific Ocean. 

In the apotectonic phase, the situation of the 
Neogene geosynclines was quite similar to what 
has been outlined by Kossmat. The crust, which 
became greatly stiffened and rigidified by folding 
and by the masses of basic rocks intruded 
into it, was no longer foldable. Further tectonic 
disturbances appeared in the form of faulting. 
The geosynclines were pinched in between fault 
slices of an imbricate thrust system at the end of 



Pliocene. It is remarkable to note that this 
diastrophic pulse thus regarded as paroxysmal 
was accompanied by the eruption of andesitic 
lavas representing a definite concentration of the 
erupted material around open spots, thus indi- 
vidual volcanoes were built up. This concen- 
tration itself is the final stage in the history of the 
eruption which started as fissure eruption at the 
stage of the nascency of the geosynclines. 

In summerizing the above, it is clear that the 
Neogene marginal geosynclines began their 
formation as a result of volcanism and the history 
of the geosynclines is definitely marked by 
eruption of submarine andesitic or basaltic 
pyroclastics at the initial stage or prototectonic 
stage, intrusions of ultrabasic rocks at the 
syntectonic stage or stage of folding and eruption 
of andesitic lavas in the form of volcanoes 
accompanied by hydrothermal concentration of 
ore-forming solutions at the epitectonic stage. 

CONTINENTAL RIFTING AND 
GROWTH OF THE CONTINENT 

The geosynclinal belts have long been recog- 
nized as technically mobile and magmatically 
active. The destruction of geosynclines by com- 
pressional deformation has been analysed by 
Rich (1951) to appear in a consistant cycle of 
events comprising (1) upwarping caused by the 
rising of magma, (2) thrusting and crumpling at 
the geosynclinal margins, (3) overriding and fold- 
ing of sedimentary rocks near the upwarp, (4) the 
repeated thrusting from the same direction after a 
period of halts, (5) development of tension in the 
upwarped area after thrusting has ceased, and 
(6) final sinking of the upwarped area accom- 
panied by outpouring of lava. 

The sequence of events in the life cycle of the 
prthogeosyncline of Taiwan, though not conform 
in detail to the above, is essentially the same as 
outlined. The tectonic land within the Neogene 
orthogeosyncline consists of two parts, the Meso- 
Palaeozoic (TLO) and the Paleogene (TLY) 
tectonic land, representing probably the ancient 
marginal geosynclines. The Meso-Palaeozoic 
tectonic land is occupied by granite gneisses 
and amphibolites and crystalline schists of 
Palaeozoic age injected by pegmatite and quartz 
dykes of possibly Cretaceous age. This mountain 
range forming the nucleus of the cordillera has 
thus been in existence since the Mesozoic era. The 
Paleogene tectonic land was a geosynclinal depres- 
sion broadly downwarped on the flanks of the 
cordillera during the Paleogene, and was region- 

177 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



ally metamorphosed into slates and phyllite 
formations by the Neo-Taiwanian revolution at the 
end of the Eocene and also dislocated at the close 
of Oligocene. Jt is the writer's conviction that the 
dislocations like the Alishan fault and the East 
Coast fault among other recurrent faults origi- 
nated far back during this period in the nature of 
rifts, initiated in the Neogene geosynclines on 
both flanks of the cordillera. When the orogenic 
deformations occurred in the Neogene geosyn- 
clines are traced in detail, we realize that the 
events of development of tension and final 
sinking of the upwarped areas accompanied by 
outpouring of lavas enumerated by Rich were 
actually continental rifting of the foreland areas 
of the ancient geosynclines at least in this particu- 
lar region. 

Geologists have been cognizant of the fact that 
the island of Taiwan is situated at the intersec- 
tion of two mighty island arcs, the Riukiu islands 
and the Philippines and that it has a curvature 
looped in a reverse direction instead of being the 
same as its neighbours which show convex fronts 
facing the Pacific Ocean. It is also generally held 
that the mechanism responsible for the formation 
of island arcs is mainly of underthrusting of a sima- 
tic layer of the crust under the ocean and its coun- 
terpart overthrusting and overriding the sial layer 
from the direction of the broad epicontinental 
seas behind the arc. Thus repeated low-angle 
thrusting dipping landward occurred in all arc 
structures. When we examine the directions of 
compression in the neighbouring arcs which 
are about N 35-50W in the Riukiu arc and 
about N 60-75E in the Philippine arc, it is 
not surprising to find that the resultant tension 
should be in the direction of N 5-20E and it 
should be manifested best at Taiwan, the location 
of intersection. This explains well the fact why 
continental riftings of the above mentioned 
direction were developed in this particular region 
where, owing to lack of epicontinental seas be- 
tween the Asiatic continent and the marginal 
geosynclines, the repeated thrustings in the cycle 
of congressional deformation came all from 
the southeast and were dipping oceanward, and 
final sinking of the foreland area of the Paleogene 
geosyncline accompanied by fissure eruption 
became the new site of a Neogene geosyncline. 
This working hypothesis seems to fit the require- 
ments of the Neogene geosynclines and to explain 
logically also the fissure eruption displayed 
at the beginning of the Pleistocene in the Taiwan 
Strait, the foreland area of the Neogene miogeo- 
syncline ; and the fact that a new geosyncline has 
178 



started and is still in its stage of geosynclinal 
sedimentation. 

There are different views about the origin of the 
islands in the western Pacific. The old idea of 
continental fragmentation is generally regarded 
as untenable. For the advances in knowledge of 
the nature of continents and ocean beds have 
gravely raised a question whether a continent 
would under any condition break up and sink. 
Theory has also been advanced that the islands 
bordering the continent are formal marginal 
orthogeosynclinal belts and that the original 
continent was a small craton that grew as oro- 
genies consolidated such marginal geosynclinal 
belts (Lawson, 1932; Stille, 1934). The growth of a 
continent must be considered from two aspects, 
the present physical constitution and the past 
geologic record of the earth. Thus the history 
of the island of Taiwan is significant in these 
considerations. 

Responding to the isostatical adjustment caused 
by the denudation of the Asiatic continent, the 
island of Taiwan has been a marginal geosynclinal 
belt since Palaeozoic time. With the invasion of 
sialic materials at the end of the Mesozoic, as repre- 
sented by pegmatite bodies in the Central Moun- 
tain area, the belt was consolidated and a coastal 
range was added to the continent at the expense 
of simatic ocean basins. By the same process, 
an eugeosynclinal belt was formed as a new 
subsiding area outside the range at Neogene time. 
The geologic history of the island thus strongly 
suggests that the continent has been expanding 
and all evidences point toward a theory of con- 
tinental accretion. 

However, the process of continental accretion 
exerted by the Neogene eugcosyncline has been 
incompletely executed, for the latter was imma- 
turely extinguished when viewed from the fact 
that batholithic intrusions, as required in the 
normal geosynclinal cycle of events, were lacking. 
It is the writer's belief that the growth of this 
marginal geosyncline must have been interrupted 
by recurrent continental rifting, an inevitable 
result consequent to the wave of powerful com- 
pression affected by the inflow of heavy subcrustal 
materials toward the neighbouring island arcs, 
as already stated before. Since the continental 
rifting is held as the initial mechanism of develop- 
ment of an eugeosyncline, the continent must have 
been expended more rapidly through the frequent 
occurrence of vast outpouring of lava in the form 
of fissure eruption than through an intermediate 
"island arc" stage. It is therefore reasonable to 
assume on the strength of the above considera- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



tions, that where continental rifting is absent, 
the growth of the continent has reached a limit, and 
paraliageosynclines without adjoining volcanic 
belts will be developed along the border of the 
continent. 

REFERENCES 

Daly, R.A., 1912, Geology of the North Ameri- 
can Cordillera at the Forty-Ninth 
Parallel. Canada Geol. Surv. Mem. 38: 
(481), 489-490. 

Dana, J.D., 1873, On the Origin of Mountains. 
Am. Jour. Sri., 5: 347-350. 

Grabau, A.W., 1928, Stratigraphy of China. 
Pt. II, Mesozoic, GeoL Surv. China, 
Peking, pp. 744. 

Hess, H.H., 1940, Appalachian Peridotite Belt; 
its Significance in Sequence of Events 
in Mountain Building. GeoL Soc. Am. 
Bull. 57: 1996. 

Hsu, T.L., 1956, Geology of Coastal Range, 
Eastern Taiwan. Bull. GeoL Surv. 
Taiwan, 8: 39-63. 

Juan, V.C. et al, 1953, Taiwanite, a New Basaltic 
glassy Rock of East Coastal Range, 
Taiwan, and its Bearing on the Parental 
Magma-type. Ada Gcol. Taiwanica, 
5: 1-25. 

Juan, V.C., 1956, Physiography and Geology of 
Taiwan. Proc. 8th Pacific Sci. Congress. 
2:281-312. 

Kay, Marshall, 1947, Geosynclinal Nomenclature 
and the Craton. Am. Assoc. Petrol 
GeoL Bull., 31: 1289-1293. 

Kay, Marshall, 1951, North American Geosyn- 
clines. Am. Geol. Soc. Mem. 48: 143. 

Knopf, Adolph, 1948, The Geosynclinal Theory. 
Am. GeoL Soc. Bull. 59: 649-670. 

Kossmat, R, 1921, Die Mediterranen Kettenge- 
birge in Ihre Beziehung zum Gleichge- 
wichtzustande der Erdrinde. Sach- 
sischen Akad. IViss., Math-phys. Kl. 
38: (2), 46-48. As quoted by A. Knopf. 



Lawson, A.C., 1932, Insular Arcs, Foredeeps, 
and Geosynclinal Seas of the Asiatic 
Coast, Bull. GeoL Soc. Am. 43: 353-382. 

Pettijohn, F.J., 1957, Sedimentary Rocks. 2nd 
ed., Harper & Brothers, New York, 
p. 633-636. 

Rich, J.L., 1951, Origin of Compressional Moun- 
tains and Associated Phenomena. Bull. 
GeoL Soc. Am. 62: (10), 1179-1222. 

Scheumann, K.H., 1924, Pray ari ski sche Gliedcr 
der Sachisch-Fichtelgebirgischen Kris- 
tallinen I, Die Magmatische Orogene- 
tische Stellung der Fronkcnberger 
Gneisgcsteine. Sdchsischen Akad. Wiss., 
Math-Nat. Kl. Abh., 37: 7-61, 1927. 
As quoted by A. Knopf. 

Stille, Hans, 1934, The Growth and Decay of 
Continents. Research and Progress. 
1: 91-14. As quoted by A. Knopf. 

Stille, Hans, 1936, Die Entwicklung des Ameri- 
kanischen Kordillerensystems in Zeit 
und Raum. Preuss. Akad. Wiss. Phys.- 
Math. Kl. Sitzungsber. 15: 134-155. 
As quoted by a Knopf. 

Sussmilch, C.A., 1935, The Carboniferous Period 
in Eastern Australia. Austr. & New 
Zealand Assoc. Adv. Sci. 22: 83-118. 

Tyrrell, G.W., 1937, Flood Basalts and Fissure 
Eruption. Bull. Volcanologique, 1 : 90-9 1 . 

Wang, Y., 1951, A Preliminary Study on the 
so-called Dolerite of Chienshan, Heng- 
chun, Taiwan. The Formosan Science, 
5: 1-2, 39-51. 

Wang, Y., 1954, Graywacke from Nankangshan 
and its Vicinity East of Taipei City. 
Acta GeoL Taiwanica, 6: 125-131. 

Yen, T.P., 1949a, Analcite Dolerite and Analcite 
Basanite in Taiwan. Bull. GeoL Surv. 
Taiwan, 2: 25-50. 

Yen, T.P., 1949b, A Preliminary Study on the 
Alkaline Basalt of Tsaolingshan, Tachi, 
Sinchu, Taiwan. Bull. GeoL Surv. 
Taiwan, 2: 1-23. 



179 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



TECTONICS AND VULCANISM IN NORTHEASTERN MELANESIA 

RHODES N. FAIRBRIDGE 

Columbia University, New York, N. >% U.S.A. 

(Abstract) 



Several oceanographic traverses in the Fiji- 
Tonga region of the South- West Pacific by Expe- 
dition CAPRICORM of the Scripps Institution of 
Oceanography, on research vessels Spencer F. 
Baird and Horizon provided some geomorphic 
data for an interpretation of the submarine geo- 
logy. Combined with this information, careful 
contouring of other bathymetric data from exis- 
ting charts (admittedly rather meagre and imper- 
fect) permit some indication of a tectonic pattern. 

Possible short echelon ridges (WSW-ENE) 
crossing the Hunter Island Ridge, S.W. of Fiji, 
seem to confirm the theory of Hess that a dextral 
transcurrent fault (right lateral strike-slip) bisects 
the northeast part of Melanesia. A similar but 
more pronounced belt of little horst and graben 
type ridges en echelon (WNW-ESE) marks the 
E-W northern border of Melanesia, suggesting a 
second dextral transcurrent line. Here the north- 
ern Melanesian border slopes gently down to the 
Central Pacific Basin. 

In contrast, the eastern Melanesian border is 
marked by a double island "arc" with a volcanic 
inner row in the Falcon Ridge and a non-volcanic 
outer row, the Tonga Ridge (NNE-SSW). These 
are separated from the South Pacific Basin by the 
very deep Tonga Trench. This feature is non- 
arcuate but rectilinear, and may also represent a 
dextral transcurrent fault extending to New Zea- 
land. Mechanically, this spoke-like arrangement 
of strike-slips offers no ready explanation, but . 
great lateral displacements of the order of hun- 
dreds of miles seem improbable. 

In the whole regions, active vulcanicity is 
limited to the Falcon Ridge and vicinity. Isolated 
plugs of late Tertiary age occur on or near the 
Hunter and North Melanesian echelon fracture 
zones, while the central mass of Fiji, standing like 



a keystone in the center, is composed mainly of 
older Tertiary (and even Cretaceous) volcanics. 
All are dominated by the andesite series, with 
basalts playing a quite subsidiary role. No typical 
"continental" sediments or granite-type rocks are 
known in the entire area. 

The character of the sea floor of the Efate Basin 
and the Fiji Basin suggests a great complexity of 
block faulting and small volcanic cones (but no 
large seamounts ; the latter arc found only east of 
the "Andesite Line"). Numerous truncated plat- 
forms throughout the area suggest planed-ofT 
andesite complexes locally surmounted by coral 
reefs. In some cases, the reefs have been drowned 
completely, and in others they are elevated, indi- 
cating continued tectonism in the region. 

Deep focus earthquakes are restricted to the 
Tonga trend. Shallow seismicity is common 
around Fiji. Crustal structure south of Fiji is in- 
dicated by CAPRICORN'S seismic refraction 
surveys (Raitt) to be intermediate in character 
between typical oceanic and typical continental. 
Gravity surveys by submarine (HMS. Telemachus) 
are still under study by Worzel, who (personal 
communication) indicates a similar picture. 

The writer interprets N.E. Melanesia as a semi- 
continental segment of the earth's crust, in the 
process of incorporation into the continental 
mass of Australasia, but still in part foundering 
back into unsupported crustal areas "regenera- 
tion". This picture does not conform in any way 
to the standard pattern of a circum-continental 
orthogeosyncline or an epicontinental parageo- 
syncline ; on the contrary, it may provide an insight 
into the evolutions of a differentiated crust in the 
earliest history of a well-established continent. 
However, in this case, the history of volcanicity 
and differentiation began possibly no earlier than 
the Cretaceous. 



180 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



ON THE RELATIONS BETWEEN SEISMIC AND 

VOLCANIC PHENOMENA AND THE ENERGY BALANCE OF 

THE BEZYMIANNY VOLCANO ERUPTION 

G.S. GORSHKOV 

Laboratory of Volcanology, Academy of Sciences of the USSR, USSR. 



On the 22nd of October 1955, f6r the first time 
in history, an eruption of the Bezymianny Vol- 
cano on Kamchatka began, which lasted for over 
a year and proved to be very interesting. 

The eruption can be divided into five stages: 

I. Pre-eruption stage from the first volcanic 
earthquake to the first gas-explosion of the 
volcano, from September 29 to October 
22, 1955. 

II. Stage of strong ash eruptions of a volcanian 
type: from October 22 to the end of No- 
vember 1955. 

III. Stage of a moderate activity, from Decem- 
ber 1955 to March 1956. 

IV. Gigantic paroxysmal explosion on March 
30, 1956. 

V. Growth and development of the extrusive 
dome in the newly formed crater: from 
April to the end of 1956. 

I. PRE-ERUPTION STAGE 

The eruption was preceded by numerous earth- 
quakes, the total number before the eruption 
being 1285. The first shock of this swarm of 
earthquakes was recorded on September 29, 1955; 
the displacement at the Volcanological Station 
in Klyuchi (45 km from the volcano) reached II \i. 
The number of shocks and their energy increased 
every day. From October 9, the earthquakes 
were already counted in one-two hundred per 
24 hours. 

On October llth, the ground displacement in 
Klyuchi exceeded lOOji; for the first time the 
epicentre (the region of the Bezymianny) and the 
focal depth were determined. From October 
18 shocks were registered with amplitudes of 
1000 ji and more. The nature of this earthquake 
swarm enabled us to be very confident of an 
eruption to follow soon and indeed the eruption 
point was determined quite correctly. 

II. STAGE OF STRONG ASH 
ERUPTIONS 

The eruption began at about 6.30 a.m. on the 




OctNovDec Jan FebMarAprN^ Yun 
1953 1956 

Fig. 1. Diagram showing changes in number (1) and 
energy of earthquakes (2) in the course of the 
eruption. Roman figures indicate periods of 
eruption. 



22nd of October. During the first days the erup- 
tion was moderate, an ash-gas cloud not exceeding 
1 or 2 km. rose above the crater. However, the 
energy of the explosions grew daily. From Octo- 
ber 26 on, ever-growing ash-falls were taking 
place in a radius of 40-60 km. from the volcano. 
Judging from the starting points of the ash streams 

181 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



the diameter of the new crater did not exceed 
250m. 

On November 7, the activity increased consider- 
ably. On the night of November 13 the ash cloud 
reached a height of 5 km. above the crater. All 
night long giant bright lightnings flashed in the 
eruptive clouds, the ash cloud moved to the East, 
reached the Pacific Coast, and moved further 
into the open ocean. On November 14 the ash 
column reached a height of 7.5 km. above the 
crater (10.5 km. above sea level). Violent ash 
falls passed in Klyuchi on November 16-20. On 
the 17th of November twy light reigned all day 
long, light was lit in houses and streets, automo- 
biles moved with switched-on headlights. All 
street work was stopped. Sometimes the ash-fall 
intensified to such an extent that no lit windows 
and street lanterns were seen at a distance of 
1 50-200 m. 

In 24 hours the ash layer accumulated to 11.5 
mm or 7.5 kg/m 2 , reaching about 25 mm or 16 
kg/m 2 by the end of November in Klyuchi. 
During November strong ash- falls occurred with- 
in a radius of 250 km. from the volcano. The 
explosions expanded the crater, its diameter 
became 700 -800m. 

III. STAGE OF MODERATE ACTIVITY 

From early December 1955 ash eruptions 
became weaker and rare. On January 25, 1956 
the crater was thoroughly inspected by aircraft. 
The depth turned to be small with a bottom in the 
form of a sloping convex shield covered with 
pyroclastics. Evidently the November explosions 
expanded the crater and a dome began to grow. 
In February frequent, but weak, explosions were 
observed which gave rise to small incandescent 
avalanches. Comparing the earlier and late 
photographs it was found that the SW part of the 
volcano had risen. The height of the rise was * 
established to be 100 m. Such a considerable 
rise suggests an extremely powerful magmatic 
pressure which could not have discharged itself 
by pressing up but one dome inside the crater. 

IV. PAROXYSMAL EXPLOSION 

Indeed, on March 30, 1956 the eruption reached 
its culmination. An enormous explosion 
occurred on that day and destroyed the top of 
the volcano and changed not only its shape but 
also the surrounding relief completely. This 
explosion and the accompanying phenomena are 
treated in a separate report ("Kamchatka Valley 
of Ten Thousand Smokes"). 

182 



V. FINAL STAGE OF THE ERUPTION 

Following the explosion on March 30 was the 
upheaval of an extrusive (endogenous) dome in 
the new crater. The growth of the dome was as 
usual followed by weak and moderate explo- 
sions and the formation of incandescent ava- 
lanches. At the end of July 1956 the formation 
of the dome was completed, its height reaching 
320 m. above the crater bottom. 

In late autumn 1956, the eruption ended entirely 
and in December, the dome, except the very 
summit, was already covered with snow. 

EARTHQUAKES RELATED 
TO THE ERUPTION 

The Bezymianny eruption was preceded and 
followed by numerous earthquakes. Their re- 
gistration was made at the Klyuchi Volcanolog- 
ical Station, 45 km. from the volcano, with Kirnos 
seismographs with equal magnification 500 and 
intervals from 0.2 to 10 sec., as well as with Kharin 
seismographs with "peak" characteristics (mag- 
nification 10,000 at the period of 0.2 sec.). In 
both cases the registration was galvanometric 
on photographic paper. 

The total number of shocks in Klyuchi for 9 
months (from October 1955 to June 1956) was 
33,150. The number of earthquakes and their 
energy are graphically expressed in fig. 1. The 
lower curve gives the summary figure of earth- 
quakes for each decade in months, the upper 
the logarithm of seismic energy expressed in ergs 
for the same periods of time. As can be seen 
from the graph the number of earthquakes and 
their energy do not coincide. In the course of 
the eruption the number of earthquakes drasti- 
cally changed, its energy being approximately on 
the same level for a long period of time. 

In the pre-eruption stage the number of earth- 
quakes and their energy rapidly increased and; 
by the end of that period the earthquake energy 
reached a constant value of the order of 10 19 ergs 
per 24 hours whereas the number of earthquakes 
did not yet reached the maximum, being 200-220 
shocks per 24 hours at the end of the period. 

At the beginning of the eruptive stage the 
number of earthquakes rapidly reached maximum 
values of 350-400 per 24 hours. The drastic rise 
in number of earthquakes during that period was 
mainly due to very weak shocks which had prac- 
tically no reflections on the energy balance. 
Corresponding computations showed that the 
drastic increase in the number of earthquakes 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



could be stipulated by intensity rise of the explo- 
sions. By the end of the stage of intense ash 
eruptions a decrease of explosions occurred simul- 
taneously with no less rapid lessening of the num- 
ber of shocks. On November 24, 303 shocks 
were registered, while next day the number was 
down to 100 per 24 hours. 

Later, such high values as in the middle of 
November were no longer observed. 

Despite the fact that in December 1955 and 
January 1956 the number of earthquakes drasti- 
cally dropped and the visible volcanic activity 
decreased considerably, the energy of earthquakes 
retained its former level and a further eruption 
progress was expected. 

In February 1956 a certain rise in the number 
of shocks took place which is likely to be related 
to movements of the dome and explosions giving 
rise to incandescent avalanches. 

From the end of February there was a steady 
decrease of earthquake energy. It seemed that 
the eruption had been exhausted and came to an 
end. But precisely at the moment of seismic 
energy drop a giant explosion took place on 
March 30 which produced a sharp "peak" on the 
energy curve. Following this "peak" the seismic 
energy dropped down to 10 14 ergs per 24 hours 
by late June 1956. 

Despite a general drop of seismic energy during 
the growing phase of the dome the number of 
shocks in April and May 1956 noticeably 
increased reaching 300 per 24 hours on some days 
of April. This rise of shocks was likely to be 
related to the processes of the dome growth. 
By the end of June 1956 the number of earth- 
quakes lowered down to 1 per 24 hours. By this 
time the dome was already mainly shaped. Ex- 
tremely weak seismic activity continued gradually 
decreasing till the end of 1956. 

All earthquakes connected with the eruption 
of the Bezymianny Volcano differ much from the 
usual local tectonic and volcano-tectonic earth- 
quakes by their large period (2.5 to 3.0 sec. 
instead of 0.2) and peculiar maximum phase 
after the arrival of S waves. All more or less 
large earthquakes were analogous in every 
detail and had the same source and cause; they 
had an increased depth (about 50 km.) and were 
likely to occur in the zone of a volcanic hearth 
or in the lower part of the volcanic chimney. 

The number of earthquakes and partly their 
intensity are directly related to the course of the 
eruption but as has been mentioned already, the 
curve of the earthquake number and their energy 



did not coincided. The reason for this discrepancy 
is that in the computation of shocks all oscilla- 
tions are taken into consideration including very 
weak earthquakes connected with volcanic explo- 
sions and other separate surface phenomena. As 
to the energetic characteristics it primarily de- 
pended on stronger shocks which all without 
exception had an enhanced depth and were caused 
by deeper volcanic processes determining the 
general variation of the eruption. Thus, a tho- 
rough analysis of the variations of seismic phe- 
nomena can not only help in predicting time and 
place of the forthcoming eruption but also helps 
to a certain extent to forecast the variations of 
the eruption underway. 

ENERGETIC BALANCE 
OF THE ERUPTION 

The energy of several separate earthquakes was 
computed from Galitzin-and-Jeffreys formulae 
and so far as the record nature and periods of all 
the shocks were completely analogous, the basis 
was assumed to deduce the empirical energy 
formula for that group of earthquakes by the 
seismographs of the Klyuchi Station : 

Ig E=lg A 2 + 13.45, 

where E is the earthquake energy in ergs, A- 
ground displacements in micrones. From that 
formula the energy of all the earthquakes was 
determined. The summary energy of all the earth- 
quakes proved to be E x = 2.3 x 10 21 ergs. 

So far as during earthquakes in the form of 
seismic oscillations about 1/300 of the total 
energy is spent, the total tectonic energy released 
during the Bezymianny eruption is equal to ap- 
proximately 7 x 10 2 3 ergs. 

Proceeding from the volume (ab. 3 km. 3 ) and 
mass (5.5 x 10 9 grams) of the agglomerate flow, 
from the thermal capacity of rocks (1.1 x 10 7 ergs) 
and original temperature of the eruptive substance 
(minimum of 600), the thermal energy of the 
eruption is determined to be 3. 6 x 10 25 ergs. 

Thus, the tectonic energy of the eruption makes 
for no more than 2 per cent of the thermal energy. 
Hence it follows that magmatic energy should be 
considered as the primary factor, and the seismic 
effects as the secondary factor of the eruptions. 

The energy of the explosion on March 30, 1956 
can be estimated in several ways : 

1 . Calculations were made of the energy of the 
earthquakes connected with the explosion. The 
mean energy from data of five seismic stations in 

183 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



the Far East was found to be E = 10 20 ergs. 
Counting that about 0.1 percent of the total 
energy of the eruption is emitted as seismic oscil- 
lations, it was determined to be 10 23 ergs. 

2. The explosion energy can be estimated by 
the air wave of the explosion (Taylor's formula) 



E = 



2n RH sin y 
" 



I 



where R is the Earth's radius, H - the height of a 
homogeneous layer of the atmosphere (13,000 m.), 
v - sound velocity, p - air density at the Earth's 
surface, y - distance from the explosion source in 
degrees, P - pressure, t - time. 

The average value of the air wave from records 
of eight meteorological stations located at a dis- 
tance of 45-780 km. from the volcano made for 
3 x 10 22 ergs. During the volcanic explosions 
about 10 per cent of the total energy transforms 
into the air waves. Hence the explosion energy 
is about 3 x 10 23 ergs. 

3. The explosion energy can be also determined 



by the mass and velocity of the material ejected 
by the explosion. 

E = 

The mass of the material ejected by the explo- 
sion is estimated to be 1.2 x 10 9 tons, the average 
initial velocity of the explosion is equally 360m/ 
sec. Hence kinetic energy of the explosion is 
about 8 x 10 23 ergs. 

The mean value of the explosive energy on 
March 30 is equal to 4 x 10 23 ergs. Thus, the 
explosion energy makes for only one per cent 
from the total thermal energy of the eruption. 
As it can be seen the share of gaseous energy is 
more than modest. From this point of view the 
known state by F. Ferret: "gas is the active agent 
and the magma is vehicle" is not correct. It is 
evident that the main active force of the eruption 
is thermal energy of the magma while gas is only 
a transformer of that energy into an explosive one 
and the efficiency of a volcano as a heat engine 
is very low. 



184 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



VOLCANIC ZONE OF THE KURILE ISLANDS 

G. S. GORSHKOV 

Laboratory of Volcanology, Academy of Sciences of the USSR, USSR. 



The volcanic zone of the Kurile Islands was 
until recent one of the least studied volcanic zones 
of the Globe. The first information on some vol- 
canoes was brought to Moscow by Cossack 
Kozyrevsky in 1713. A thorough description of 
several volcanoes was compiled in 1769 by I. 
Cherny. These data were published in German 
by P.S. Pallas in 1783 and have become widely 
known. After the transfer of the islands to Japan 
special volcanological investigations were con- 
ducted by J. Milne in 1878 and 1885. All further 
summaries repeated the data obtained by I. Cherny 
and J. Milne. The latter author reports 52 vol- 
canoes from the Kurile Islands, of which 17 are 
active. 

Japanese scientists (Tanakadate, etc.) published 
new data in European languages but only for the 
Taketomi crater, an adventive crater of the Alaid 
Volcano, which originated in 1934. Our own 
investigations started in 1946 and were contin- 
ued in 1951-1954. These investigations embrace, 
to a certain extent, all the islands of the archi- 
pelago, and permitted to get a general idea of 
nearly all active and of several extinct volcanoes 
of the Kurile Island arc. At least 89 volcanoes, 
including 39 active ones, were found. 

The Kurile arc, like some other island arcs, 
is a double one. The outer arc forms the Small 
Kurile Ridge, the greater part of which is hidden 
under the ocean waters forming a submarine 
ridge, called the Paleokuriles in 1947 by the 
author, and thoroughly investigated by the Insti- 
tute of Oceanology of the USSR Academy of 
Sciences in 1950-1951, with the expeditionary 
ship "Vityaz". The internal arc forms the Big 
Kurile Ridge, the place of concentration of recent 
volcanic activity. 

The islands of the outer arc are composed 
of Cretaceous and Lower Tertiary sedimentary 
and volcano-sedimentary rocks with intrusions 
of gabbro-diorites. 

The foundation of the internal arc is composed 
of sedimento-volcanogeneous rocks and intru- 
sions of leucocratic plagio-granites and grano- 
diorites of Upper Tertiary. 

The map shows the location of active and extinct 
volcanoes. The numbers of the volcanoes are 
corresponding to those in table I. First of all, 



the eye is caught by a linear arrangement of the 
majority of the volcanoes along definite lines 
following in general the trend of the arc with, a NE 
direction. Nevertheless, the rows of volcanoes 
do not follow exactly the direction of the arc but 
intersect it somewhat obliquely forming compara- 
tively short echelon sections, deviating north- 
wards from the general trend of the arc. Espe- 
cially distinct is the echelon structure of the vol- 
canic rows in the northern part of the arc; in the 
larger southern islands, where much space is 
occupied by Tertiary rocks, the echelons are only 
expressed vaguely. It is interesting to note that 
tne chains of Tertiary volcanoes have different 
directions, deviating form the trend of the 
Quaternary volcanoes eastwards by approximate- 
ly 20. 

Besides the volcanic chains longitudinal to the 
trend of the arc, there are also transversal rows 
in north-western direction. There are reasons 
to believe that the transversal rows are younger 
that the longitudinal ones. 

The most active recent volcanoes are usually 
situated in the transversal rows, especially at the 
intersection of longitudinal and transversal rows. 
In addition the "intersections" are the locations 
of the longest active volcanoes, from Early 
Quaternary, sometimes from the Late Tertiary 
epoch till Recent. 

Table I gives the list of volcanoes of the Kurile 
Arc, geographical position and altitude, short 
characteristics of each volcano and date of the 
last eruption. The active volcanoes are under- 
lined. Further investigations may lead to the 
discovery of more extinct volcanoes on the large 
islands of the arc, but the number of active vol- 
canoes will hardly be changed. 

From the table we see that form and structure 
of the volcanoes are very different. Stratovol- 
canoes are predominating, pure lava volcanoes 
are rare. The role of endogeneous (extrusive) 
domes is very significant. The prevailing form 
of the volcanoes is the Somma-Vesuvius-type, 
sometimes developed in such an excellent form 
as the Krenitsyn Peak or Tyatya; occasionally 
this type is complicated by erosion or tectonic 
disturbances. 

185 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




" V 




186 



Ideal single cones (Alaid, Prevost Peak, etc.) 
and well-developed calderas (Karpinsky, Lvinaya 
Past, etc) occur frequently. Caldera-walls are 
usually incomplete. Many active volcanoes have 
crater lakes (Ebeko, Pallas, etc). 

The type of the latest eruptions is rather dif- 
ferent. The prevailing type is Volcanian (Ebeko, 
Cherny, etc.), or Strombolian (Alaid, Chikurachki, 
Nemo Peak, etc.). Also violent eruptions of the 
Plinian type (Severgin, Raikoke, etc.) occur. 
Outpourings of extensive lava flows occur less 
frequently (Goryashchaya Sopka in 1881, Snow, 
Menshoy Brat in the Medvezhi Caldera). Widely 
spread are upheavals of endogeneous domes 
(Sinarka in 1878, Goryashchaya Sopka in 1883, 
etc.). Very often destructive incandescent ava- 
lanches come down along the slopes of volca- 
noes (Sinarka, Sarychev Peak, etc.). 

Three big eruptions occurred since 1945: the 
Sarychev Peak erupted on Matua Is. in 1946, the 
eruption was characterized by strong incandescent 
avalanches the deposition of which changed the 
contours of the coastal line. In 1952 Krenitsyn 
Peak, the central cone of the big Caldera Tao- 
Rusyr on Onekotan Is., became active; at first a 
lateral explosive crater originated, then at the 
foot of the cone a submarine one was formed in 
which an endogeneous dome developed. In 1957 
an eruption took place in the crater lake of Zava- 
ritsky Caldera on Simushir Is., which resulted in 
considerable changes of the contours of the north- 
ern part of the lake. 

The petrographical and chemical composition 
of recent lavas is rather different. The dominant 
part of it belongs to pyroxenic andesites with 
rhombic and monoclinal pyroxene. Biotitic 
andesites can be encountered on Fuss Peak. 
Many volcanoes, especially those with pumiceous 
pyroclastics, produce acid hornblende andesites 
which are often transformed into dacites. Among 
lavas and slags frequently occur andesite-basalts 
and even basalts. Table II gives a few analyses of 
recent lavas. 

The geological history of the Kurile arc before 
the Upper Mesozoic is not known. The Lower 
Cretaceous was accompanied by folding move- 
ments with intensive volcanic activity. The Upper 
Cretaceous was characterized by sea transgres- 
sion and decrease of volcanism. In Late Mesozoic 
and Early Cenozoic orogenic movements, ac- 
companied by basic intrusions took place, at the 
same time the Little Kurile arc was completed. 
In the Tertiary the area of the Big Kurile arc was 
a region of shoal water and intensive submarine 
and subareal volcanic activity. Between Miocene 



VOLUME 12 



and Pliocene folding and intruslions of granite 
occurred, followed by a general upheaval and 
intensive erosion. During the Late Tertiary 
volcanism renewed its activity and continued till 
recent times. In the Quaternary upheaval and 
depression of land formed a number of submarine 
and subareal terraces. At present the region of 
the Big Kurile Ridge is lifted up, while the Little 
Kurile Ridge is submerging. 

At the beginning of the glacial period all 
modern calderas and sommas of complex vol- 
canoes were formed. Two stages of congelation 
with weak volcanic activity during the interglacial 
were known on the northern islands. Jn post- 
glacial, and partly in interglacial time, modern 
central cones of the complex volcanoes and some 
simple volcanoes (Alaid, Fuss Peak, tentatively 
also Chirinkotan) originated. The Recent vol- 
canic activity is but a weak remainder of that 
during the early part of the Quaternary. 

Table 1 

List of Volcanoes 
on the Kurile Islands 1 

Name of volcano Geographic position Height 

ALAID IS. 

1. Alaid 5051'5 155 C 34 / 2339 

Isolated cone with adventive cones. 
Top eruption- 1894, lateral- 1934. 
PARAMUSHIR IS. 

2. Vetrovoy 50 C 43' 15603' 1088 

Much destroyed, pre-glacial. 

3. Ebeko (Jo Ruko) 5041' 15601' 1138 

The pre-glacial somma destroyed, 
central cone with 3 craters, in one of 
which there is a warm lake. Erup- 
tions in 1934/35. 

4. Neozhidanny. 5040'8 15601 f 7 1066 
(Fusikei) 

Post-glacial cone with lava-flows. 

5. Slag cone. 5040'5 156 C 01'3 900 

The same. 

6. Nasedkin. 5039' 15600' 1152 

Pre-glacial, destroyed. 

7. Bogdanovich. 5037' 15559'5 1056 

Maar with a fresh lake. 

8. Kozyrevsky. 5036' 15600' 1161 

Post-glacial cone with lava bocca. 

9. Krasheninnikov. 5036' 156W5 950 

Post-glacial cone with a large lava-flow. 



Name of volcano 
10. Bilibin 



GEOLOGY AND GEOPHYSICS 

Geographic position Height 

5033'5 15558' 1080 



857 



1052 



894 



The same. 

11. Vernadsky. 5033' 15557'5 1184 
(Taise) 

Destroyed volcano with traces of post- 
glacial activity. 

12. Levashov. 5031' 15604' 
(Mitsuga) 

Pre-glacial, partly destroyed. 

13. Fersman. 5030'5 15550' 
(Aragava) 

Pre-glacial cone in a caldera. 

14. Arseniev. 5023' 15548' 
(Takahiza) 

Tertiary caldera- volcano, destroyed. 

15. Levinson- 5017' 15541'5 818 
Lessing. (Komaga) 

Tertiary, much destroyed. 

16. Chikurachki 5019'5 15527'5 1817 

Post-glacial cone, on the edge of an 
ancient volcano. Erupted in 1853/59. 

17. Tatarinov. 5018'5 15526'5 1593 
(Oruka) 

Pre-glacial caldera-volcano. Explo- 
sions in the post-glacial time. Solfa- 
tara activity. 

18. Lomonosov. 5015' 15526' 1682 
(Kamuri) 

Complex volcano with post-glacial 
flows and domes. 

19. Arkhangelsky. 5013' 155 U 25' 1463 

Destroyed, pre-glacial. 

20. Karpinsky. 5009' 15522' 1377 
(Hakuen) 

Pre-glacial caldera, with post-glacial 
effusion and explosions. Solfatara 
activity. 

21. Fuss Peak. 5016' 15515' 

Single cone. Erupted in 1854. 
SHIRINKA IS. 

22. Shirinka. 5012' 15459' 

Isolated strato-volcano. 
MAKANRUSHI IS. 

23. Makanrushi. 4947' 15426' 

Destroyed caldera-volcano. 

AVOS ROCK 

24. Avos. 4943' 15406'5 34 

Top of the ancient submarine volcano. 
ONEKOTAN IS. 



1772 



748 



1169 



Active Volcanoes are italicized; notes refer to last eruption; height in meters. 



187 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Name of volcano Geographic position Height 

25. Asyrmintar. 4936' 15454 / 570 

Single strato- volcano. Erupted in 1938. 

26. Nemo Peak. 4934' 15448'5 1019 

Central cone in a large destroyed cal- 
dera Amka-Usy. Erupted in 1906. 

27. Shestakov. 4928'5 15444' 708 
(Encio) 

Ancient destroyed massive. 

28. Kryzhanovsky. 49 25' 15442' 551 

Ancient caldera-volcano. 

29. Krenitsyn Peak. 4921'5 15442 / 5 1325 

Central cone in the form of an island 
in the caldera lake of the Tao-Rusyr 
Caldera. Erupted in 1952. 

KHARIMKOTAN IS. 

30. Severgin. 4907' 15431' 1145 

Low cone plugged up by the dome in 
a destroyed E somma. Erupted in 
1933. 

SHIASHKOTAN IS. 



31. Sinarka. 



4852'5 154 10'5 934 



The somma destroyed by sector trough 
faults. A dome in the crater of the 
central cone. Erupted in 1878. 

32. Kuntomintar. 484V5 154 '01' 828 

Semi-caldera with a small central cone. 
Erupted in 1872. 

ECARMA IS. 

33. Eastern Ecarma. 4857' 15358 / 796 

Destroyed volcano. 

34. Ecarma. 4857' 15356'5 1171 

Single strato- volcano. Erupted in the 
1760-ies. 

CHIRINKOTAN IS. 

35. Chirinkotan. 4859' 15329' 742 

Post-glacial caldera-volcano. Erupted 
in the 1880-ies. 

LOVUSHKI ROCKS 

36. Stone Lovushki. 4832' 15351' 42 

Top of an ancient submarine volcano. 
RAIKOKE IS. 

37. Raikoke. 48 15' 153 15' 551 

Single cone. Erupted in 1924. 
MATUA IS. 

38. Sarychev Peak. 4805'5 15312' 1498 

Central cone with destroyed somma. 
Erupted in 1946. 

39. Submarine. 4805' 15320' 

Two submarine eruptions in 1924. 

188 



Name of volcano Geographic position Height 
RASSHUA IS. 

40. Rasshua. 4746' 15301' 956 

Destroyed somma with 4 cones. 
Erupted in 1846. 

SREDNY STRAIT 

41. Karlic. (Dwarf) 4739' 15257' 1 

Summit of a submarine volcano. 

SREDNY ISLETS 

42. Sredny. 4735' 15252 / 27 

Summit of an ancient submarine vol- 
cano. 

USHISHIR ISLES 

43. Ushishir. 4731' 15249' 401 

Somma divided into two small isles, 
a crater bay with residues of the cen- 
tral cone and domes-in a caldera. 
Phreatic eruption in 1884. Solfataras. 

KETOY IS. 

44. PallacePeak. 4721' 15228'5 993 

Excentric cone with a hot lake in the 
crater on the edge of the Ketoy Cal- 
dera (1172 m). Erupted in 1924. 

SIMUSHIR IS. 

45. Uratman. 4707'5 15214' 679 

Partly destroyed cone in a caldera oc- 
cupied by a crater bay down to 266 m 
in depth. 

46. Prevost Peak. 4701' 15207' 1361 

Isolated cone, Erupted early in the 
XIX century. 

47. Ikanmikot. 46 C 58' 15204' 645 

Destroyed cone. 

48. Zavaritsky. 4655'5 15157' 625 
(Midori-Ko) 

Two inside caldera- volcanoes. In the 
inner caldera a lake with slag cone 
and two domes. Erupted in 1957. 

49. Milne. 4649' 151 47' 1539 

Somma destroyed from SE, the central 
cone plugged up with a dome. 

50. Goryashchaya 4650' 15145' 890 

Sopka. 
(Glowing Mountain) 

Strongly destroyed somma, the central 
cone crater plugged up with a dome; 
large lava-flows. Erupted in 1944. 

BROUGTON IS. 

51. Brougton. 4643' 15044' 800 

Destroyed strato volcano. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Name of volcano Geographic position Height 
BLACK BROTHERS ISLES 

52. Chirpoi. (Daiho) 4632' 15052'5 691 

Destroyed double strato-volcano. 

53. Cherny (Io-san) 4631'5 15052'5 624 

Single cone with adventive craterlets. 
Erupted in 1857. 

54. Snow. 4631' 15052'5 400 

Single lava cone with, abundant lava- 
flows. Erupted in 1879. 

55. Chirpoev Brat. 4628' 15048'5 752 

Much destroyed somma with a central 
cone. Fumarolic activity in the XVIII 
century. 

URUP IS. 

56. Desantny. 46 IT 15023' 866 
(Daisanto) 

Tertiary volcanic massive. 

57. Antipin. 4609' 15014' 1222 
(Zurigane) 

Cone destroyed from the south. 

58. Trezuhets. 4604' 15007' 1018 
(Trident) 

Somma destroyed in N (1222 m.). 
The central cone a dome with an ex- 
plosive crater. Erupted in 1845/46. 

59. Berg. 4604' 15005' 900 

Somma in N destroyed (1108). The 
central cone a dome with small flows. 
Erupted in 1951/52. 

60. Caldera. 4604' 15003' 1100 

Ancient caldera with NW destruction. 

61. Kolokol (Bell) 4603' 15003'5 1326 

Single cone with a destroyed crater. 
Erupted in 1894(7). 

62. Borzov. 4603' 15003' 1120 

Destroyed single cone. 

63. Kavraisky. 4557'5 15003'5 842 

Tertiary cone. 

64. Tri Sestry. 4555'5 14954' 999 
(Three Sisters) 

Much destroyed volcano with traces 
of recent fumarolic activity. 

65. Rudakov. 45 C 52' 14949' 543 
(Daiba) 

Single cone with a freshwater lake. 

66. Ivao. 5444' 14940' 1426 

Complex volcano with a lake in the 
destroyed crater. Post-glacial lava 
flows. 

ITURUP IS. 

67. Kamui. 4531' 14849' 1323 

Ancient caldera-volcano, destroyed 
from NE. 



Name of volcano Geographic position Height 

68. Medvezhiy. 4523' 14848' 1125 

Partly destroyed somma. Three cen- 
tral cones: Kudryavy (988), erupted 
in 1883; Menshoi Brat (563 m) violent 
lava-flows. 

69. Caldera. 4521' 14847 / 854 

Ancient, nearly completely closed. 

70. Chirip. 4523' 14755' 1564 

Single cone on the ancient caldera 
edge. Erupted in 1860. 

71. Bogdan 4520' 14755' 1589 
Khmelnitsky 

Partly destroyed strato-volcano. 

72. Baransky. 4506' 14802' 1126 
(Jiusu) 

Single cone with a lava plug in the 
crater. Erupted in 1951. 

73. Tebenkov. 4501' 04755' 1212 
(Kotamo!) 

Extinct central cone, with a large ex- 
plosive crater Machekha with fuma- 
rolic activity on the somma slope. 

74. Ivan Grozny. 4500'5 14752' 1158 
(Sio) 

Very complex volcano, much des- 
troyed somma. At the summit of the 
central cone three domes. In the 
atrio endogeneous and exogeneous 
domes. Solfataras. 

75. Motonopuri. 4459'5 14750' 953 

Ancient strato-volcano. 

76. Rebunshiri. 4458'5 14748' 782 

Ancient strato-volcano. 

77. Burevestnik. 4452'5 14727'5 1427 
(Onneto) 

Ancient destroyed volcano. 

78. Stokap. 4450' 14720' 1566 

Ancient strato-volcano with traces 
of post-glacial activity. 

79. Atsonupugri. 2449'5 14707'5 1205 

Isolated cone with residues of somma 
on its slope. Erupted in 1932. 

80. Urbich. 4438' 14712' 907 

Ancient caldera-volcano with a lake. 

81. LvinayaPast. 4437' 14700' 403 
(Moikesi) 

Ancient caldera-volcano with a bay 
down to 460 m in depth. 

82. Berutarube. 4428' 14656' 1222 

Destroyed shield volcano with post- 
glacial flows. Solfataras. 

189 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Height 



86. 



Name of volcano Geographic position 
KUNASHIR IS. 

83. Rurui. 4427' 14608' 1486 

Single strato-volcano with a destroyed 
crater. 

84. Tyatya. 4421' 14615' 1822 

Somma with well-preserved fine cal- 
dera. A small central cone with lava 
flows into the caldera mouth. Erupted 
in 1812. 

85. Otdelny. 4402' 14546'5 476 

Destroyed volcano. 

Mendeleev. 43 U 59' 14542' 890 

(Ratisu) 

Somma and central cone partly des- 
troyed. A dome in the crater, des- 
troyed lateral craterlets on the slopes. 
Erupted in 1880. 

Gohvnin. 4353' 14532' 547 

(Tomari) 

Caldera- volcano with a deep freshwater 
lake. Two domes and explosive cra- 
ters in the caldera, a hot lake in one 
crater. Erupted in the XIX cent. 

SHIKOTAN IS. 

88. Notoro. 4346'5 14641' 358 

Ancient destroyed cone. 
Tomari. 4346' 14644' 356 

Ancient destroyed cone. 

Table 2. 

Chemical Analysis of Lavas of the Kurile 
Volcanoes. 



87. 



89. 



Samples 1 


2 


3 


4 


5 


6 


7 


SiO 2 


50.29 


51.75 


53.33 


54.80 


58.07 


61.91 


65.30 


Ti0 2 


1.28 


1.20 


0.95 


0.73 


0.68 


0.75 


1.22 


AI 2 3 


18.96 


17.20 


18.60 


18.84 


17.21 


16.89 


15.84 


Fe 2 3 


3.44 


3.95 


4.21 


5.79 


3.61 


3.14 


3.08 


FeO 


6.75 


7.58 


4.63 


2.30 


4.23 


3.89 


2.40 


MnO 


0.33 


0.22 


0.18 


0.16 


0.16 


0.21 


0.14 


MgO 


4.14 


4.02 


4.00 


3.70 


3.()4 


2.20 


1.70 


CaO 


10.25 


10.32 


9.34 


8.60 


7.41 


5.96 


5.12 


Na 2 O 


2.85 


2.12 


3.38 


2.67 


3.19 


3.21 


3.70 


K 2 


1.25 


0.96 


1.09 


2.22 


2.02 


1.01 


1.65 


H 2 


0.20 




0.21 


0.10 


0.10 


0.32 


0.13 


H 2 


0.09 


0.51 





0.30 


0.28 


0.62 


0.11 


P20 5 


0.40 


0.50 


n.d. 


0.05 


0.02 


n.d. 


0.09 


S 


0.02 


n.d. 


n.d. 


0.06 


0.05 


n.d. 


n.d. 



No. 1 Andesite-basalt, Vole. Alaid, Crater 
Taketomi, eruption 1934. Coll. Tana- 
kadate, anal. Jap. Geol. Survey. 

No. 2 Andesite-basalt, Vole. Tiatia, eruption 
1812? Coll. Zhelubovsky. 

No. 3 Andesite-basalt, Peak Sarychev, erup- 
tion 1946, Coll. Gorshkov, anal. 
Tovarova. 

No. 4 Biotite-andesite, Peak Fuss, coll. Gor- 
shkov, anal. Posnikova. 

No. 5 Andesite, bread-crust bomb, Vole. 
Ebeko, eruption 1935. Coll. Gorshkov, 
anal. Tovarova. 

No. 6 Andesite, Peak Krenitsyn, ash, erup- 
tion 1952. Coll. Piip, anal. Tovarova. 

No. 7 Dacite, dome, vole. Mendeleev, coll. 
Gorshkov, anal. Tovarova. 



Total 100.25 100.33 99.92 100.32 100.07 99.75 100.48 



REFERENCES 

Gorshkov, G.S., Catalogue of the active vol- 
canoes of the World, Part VII Kurile 
Islands. Jnt. Vole. Ass. Napoli (in press). 

Kuno, H., 1935, Petrology of Alaid volcano. 
Jap. Journ. Geol. Geogr. 12 : (3-4), 
Tokyo. 

Milne, J., 1886, The volcanoes of Japan. Trans. 
Seism. Soc. Japan, 9, (2), Yokohama. 

Tatarinov, M., 1783, Neue Beschreibung der 
Kurilischen Inseln. Neue Nordische 
Beitrage, Bd. 4. SPb. 



190 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



TO THE QUESTION OF CAINOZOIC VOLCANISM IN 
SOUTHERN SAKHALIN 

V. N. SHILOV 
Sakhalin Complex Scientific Research Institute, USSR. 

(Abstract) 



In the thick section of Tertiary deposits of 
Southern Sakhalin a substantial place is occupied 
by volcanic rocks. Their presence is associated 
with manifestations of three independent phases 
of effusive volcanism on the island. The main 
manifestations of the first phase relate to Lower 
Miocene; of the second, to Middle Miocene and 
the third, to the second half of Pliocene. 

Intrusive manifestations were associated with 
all three phases of volcanic activity. On a limited 
part of Southern Sakhalin without an apparent 
relation to effusive volcanism an injection of 
basic magmas of an increased alkalinity into 



the subsurface parts of the crust took place with 
a formation of hypabyssal bodies. The age of 
the subalkaline intrusions is approximately 
Lower Pliocene. Manifestations of volcanicity on 
Southern Sakhalin took place on the background 
of its geosynclinal development during the Tertiary 
period. 

From the chemical point of view the products 
of all phases of effusive volcanism form a normal 
calcareous-alkaline series, while the products of 
independent hypabyssal injections form a subal- 
kaline series. 



191 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



A PRELIMINARY ACCOUNT OF CRETACEOUS TO RECENT 

VOLCANIC ACTIVITY IN RELATION TO THE GEOLOGICAL 

STRUCTURE OF BRITISH BORNEO 

H. J. C. KIRK 

Geological Survey Department, British Territories of Borneo, Sarawak. 



INTRODUCTION 

This preliminary account summarizes infor- 
mation gained to-date from the systematic region- 
al geological survey of British Borneo now in 
progress under the direction of F.W. Roe, Director, 
Geological Survey Department. Information on 
the volcanic rocks of east Sarawak is mainly 
from surveys by the author; work published on 
other parts of British Borneo which has been 
referred to is given in the list of references. A 
more comprehensive account, including further 
work on the volcanic rocks of North Borneo, 
will be given when the writer has completed his 
regional study of the igneous rocks of British 
Borneo, and regional surveys now in progress 
have been completed. 

British Borneo is built mostly of Upper Meso- 
zoic and Cainozoic sedimentary rocks laid down 
during the development of the Cretaceous to 
Recent geosyncline, and most fully developed in 
the central and northern region. The main 
events in the history of the geosyncline are 
summarized in table 1, and figure 1 shows the 
distribution of volcanic rocks in relation to the 
Cretaceous and Tertiary sediments. The Palaeo- 
zoic and Mesozoic rocks of west Sarawak, west of 
the Lupar Valley, belong to the stable block of 
the Sunda Shelf which extends over much of 
western Kalimantan, the South China Sea, and - 
the Malayan Peninsula. Extensive subsidence 
during Cretaceous times in the central and north- 
ern area initiated the development of the geosyn- 
cline when it was marked by the deposition of 
great thicknesses of Cretaceous and Lower tertiary 
sediments in the resulting, wide, trough-shaped 
depression. These sediments, the Rajang Group, 
which are at least 45,000 feet thick in southern 
Sarawak, were strongly folded and uplifted during 
Upper Eocene times in Sarawak, and in the 
Lower Eocene and Oligocene times in North 
Borneo. They form a zone of highly folded 
sedimentary rocks which is one of the main 
structural features of the region. The thick 
Upper Tertiary and later sediments have accu- 

192 



mulated in basins along the margins of the up- 
lifted older sediments. 

VOLCANIC ROCKS 

Two main periods of volcanic activity, associ- 
ated with the structural development of the geo- 
syncline, have occurred as follows : 

(i) Basalt- spilite association consisting of pre- 
tectonic extrusive occurrences of basalt and 
spilite, interbedded with the Cretaceous and 
Eocene sediments of the first, and main, 
phase of sedimentation. A little rhyolite 
also occurs but is relatively rare. 

(ii) Basalt-andesite-dacite association formed 
during widespread eruptions of volcanic 
rocks during Upper Tertiary and Quater- 
nary times which took place from volcanic 
centres situated on the areas of folded 
Cretaceous and Lower Tertiary sedimentary 
rocks. 

BASALT-SPILITE ASSOCIATION IN 
SARAWAK 

In the Lupar Valley, in southwestern Sarawak, 
an outcrop of Danau Formation, about ten 
miles wide, comprising mainly shale, chert, marl 
and limestone, with associated basalt and spilitic 
lavas and pyroclastic rocks, extends westwards 
from the Lakes (lake = Danau in Malay and this 
is the type locality for the Danau formation) 
area of Kalimantan. The formation which has 
been dated by foraminifera to be mainly Creta- 
ceous and partly Paleocene and Lower Eocene, 
is contemporaneous with the lower part of the 
thick geosynclinal facies of the Rajang Group 
lying to the northeast of the Danau Formation 
outcrop. West of the Lupar Valley, sediments 
of similar age are restricted to the Kuching-Bau 
area where a relatively thin sequence of Creta- 
ceous sediments of calcareous shelf-facies occurs. 
It therefore appears that the volcanic activity 
in the Lupar area occurred at the southwestern 



VOLUME \2 



GEOLOGY AND GEOPHYSICS 



8 
o 



1 






I 



_L 



Il ill 



if *5 
': * 55 



S3 



ii 



ick c 
Sara 



t 

% 



S5 

ill 



lillllill 



O*er 6,000 feet of das 
sediments in central 
Sarawak ( Buan Group 



c 

I 



, 






193 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



edge of the geosyncline. The regional strike of 
the volcanic rocks is west-northwest and this 
marginal volcanic zone may extend as far as the 
Natuna Islands where basic volcanic and intrusive 
rocks associated with radiolarian cherts occur 
(van Bemmelen, 1949. p. 303). In the Northern 
Usun Apau area a narrow faulted outcrop of 
Cretaceous rocks of Danau Formation fades, 
containing flows of basalt and spilite, is present 
along the northern edge of the steeply folded belt 
of the Rajang Group. These volcanic rocks 
appear to occupy an analogous position on the 
northern side of the Cretaceous to Eocene belt of 
geosynclinal sedimentation, to those on the 
southern side in the Lupar area. 

At Bukit Mersing, in central Sarawak, basic 
volcanic rocks, mainly basalt lavas, some show- 
ing pillow structure and spilitic composition, and 
thick beds of tuff and agglomerate, form a lens 
with a maximum thickness of over 5,000 feet. 
The volcanic rocks are intercalated in steeply 
dipping Upper Eocene sediments on the northern 
margin of the geosynclinal facies of the Rajang 



Group, and were evidently extruded from a 
volcano of central type situated on the northern 
margin of the geosyncline in the closing phases of 
this period of sedimentation, before the strong 
folding movements in the Upper Eocene occurred. 
Thin flows of rhyolite are intercalated in later 
Eocene sediments of the Arip Valley and were 
deposited after the main orogeny. 

BASALT - ANDESITE - D ACITE 
ASSOCIATION IN SARAWAK 

Eruptions of basalt-andesite-dacite, and rhyo- 
lite have occurred from widespread volcanic 
centres active from the Miocene to the Quaternary. 
The main volcanic districts (see fig. 1) arc in the 
Hose Mountains, Nieuwenhuis Mountains, Linau- 
Balui and Usun Apau areas of eastern Sarawak, 
and in numerous localities in central and south- 
ern Kalimantan. The distribution of the volcanic 
activity in British Borneo shows a close relationship 
to the structural history of the geosyncline; 
without exception the volcanic centres lie on, 



-Hi. 



JJL. 



Sketch-mop showing the 
VOLCANIC ROCKS AND GEOLOGICAL STRUCTURE IN BRITISH BORNEO 



SOUTH CHINA 




_ Crttoosout ond oltftr rockj in Sorowok. 

^1 Chtrt-Splltt Formation and associated 

~"~" rockt of North Bornto 

JH Volcanic rockt 

Struetvrol trtndt 

Political boundary 



KALtMANTA N 



SARAWAK eeOLOOlCAL OFFICE MAP I 



ur . 



Fig. 1. 



194 



or near, uplifted areas of folded Cretaceous and 
Lower Tertiary sediments, around which the 
sedimentation basins, of the Upper Tertiary and 
Quaternary rocks were formed. The volcanic 
belt is a continuation of the Tertiary to Recent 
volcanic arcs of the Philippines, the vulcanicity 
in eastern North Borneo being an extension to 
the chain of young volcanic centres along the 
Sulu arc. 



JOLUME 12 GEOLOGY AND GEOPHYSICS 

In the upper Rajang Valley of eastern Sarawak 
eruption of great thicknesses of mainly pyroclastic 
dacitic and andcsitic volcanic rocks occurred 
during the Pliocene, and continued until Qua- 
ternary times in the Usun Apau area. In the 
closing stages of the volcanicity basalt lava of 
late Pliocene and Quaternary age was erupted 
from several centres in the Usun Apau and 
Linau-Balui areas. In the Usun Apau, Linau- 



NORTH 

CHINA SCA 



UPPCH RAJA** 



wmitu AHCA 



SOUTH 

CfNTRAlBOftNCO 
LUPAHARCA 






SEDIMENTS BEFORE STRONG FOLDING 



SEDIMENTS AFTER OROGENESIS 



VOLCANIC ROCKS 




FEEDERS OF VOLCANIC CENTRES 
ZONES OF CRYSTAL UPLIFT 

MAJOR FAULT 

CRETACEOUS -EOCENE BOUNDARY 



SARAWAK GEOLOGICAL OFFICE DIAGRAM l6 BY H J.C. KIRK, 1937 



Fig. 2. 



195 



PROCEEDINGS OF THh NINTH PACIFIC SCIFNCE CONGRESS 



Balui area, and the Nieuwcnhuis Mountains, the 
positions of the volcanic centres show possible 
relationships to the structure of the steeply folded 
underlying sedimentary rocks; they are located 
in areas where marked changes occur in the 
regional strike (see fig. 2). From the Usun 
Apau vents it is estimated that about SO cubic 
miles of dacitic pyroclastic rocks were erupted. 
These vents are situated where the regional strike 
of the underlying sediments changes from west- 
northwest to cast-northeast and northeast; in 
addition, to the north and east of the vents there 
are marked local changes in strike of the sedi- 
ments. The basalt lavas of the Linau-Balui area 
he across the hinge region of a change in regional 
strike of the isochmilly folded Eocene sediments; 
on the western side of the basalt outcrop the 
regional strike is to the northeast, whereas on 
the eastern side the strike has changed to east- 
southeast. The volcanic centres of the Nieuwcn- 
huis Mountains are situated where the regional 
strike of the underlying folded Cretaceous sedi- 
ments changes from east-northeast in the upper 
Balch Valley, to between northeast and north- 
northeast to the north of the areas. 

TECTONIC EVOLUTION AND 
VOLCAN1C1TY IN SARAWAK 

higure 2 illustrates the tectonic evolution and 
mode of occurrence of volcanic rocks associated 
with the geosyncline in Sarawak. Early in Cre- 
taceous times an uplift of the stable block of 
Mesozoic and older rocks forming western Borneo, 
and a subsidence of the sialic layer adjoining its 
northern margin, started the development of a 
tectogcne in which over 45,000 feet of Cretaceous 
and Eocene sediments were deposited. The 
deposits were thickest along the steep southern 
limb of the tectogene, nearest the main source of 
sediment, and thinned towards the northern side 
of the geosyncline. Intense distortion of the sialic 
crust occurred at the northern margin of the thick 
sialic layer of the Sunda Shelf area of western 
Borneo, where it joined the sialic layer forming 
the southern limb of the tectogcne, and, to a 
lesser extent, in the zone of bending of the sial 
in the incipient geanticline on the northern limb 
of the tectogene. Crustal flexures in these areas 
formed zones along which the magma could 
move and gave rise to the Cretaceous and Eocene 
volcanic activity of the basalt-spilite association 
in the Lupar, northern Usun Apau, and Bukit 
Mersing areas. 

During the Upper Eocene period of orogenesis 
Eocene and Cretaceous sediments were strongly 

196 



folded and thereafter behaved as an extension to 
the core of older Sunda Shelf rocks. During the 
orogenesis, a new downfold of the crust was 
created north of the belt of folded Cretaceous 
and Palaeogene sediments, and became the subsid- 
ing basin in which the Miocene sediments accum- 
ulated. The sialic crust, thickened immensely 
by the layer of Cretaceous and Eocene sediment, 
because the site of isostatic uplift, causing major 
faulting south of the Miocene basin (in the Usun 
Apau and Belaga area) along lines of weakness 
at the crest of the now fully developed geantic- 
line. During tiie Upper Tertiary orogeny, the 
southerly directed compressional movements 
strongly folded the Miocene rocks, and forced 
large quantities of basalt, andesite, and dacite 
magma through the weakened portion of the 
crust to cause the widespread Miocene-Quater- 
nary volcanic activity. 

VOLCANIC ACTIVITY IN NORTH BORNEO 

In North Borneo, Cretaceous to Eocene volca- 
nic activity which led to the formation of the 
basalt-spilite association was more widespread 
than in Sarawak. It may be inferred that this 
is a basement formation on which the younger 
Tertiary formations were deposited. Large and 
scattered outcrops of these Cretaceous and 
Lower Eocene deposits containing volcanic rocks 
occur in eastern North Borneo, the Labuk area, 
Kudat Peninsula, and on Banggi Island (sec 
fig. 1). Unlike Sarawak, the volcanic activity 
of the basalt-spilite association appears to have 
been along a broad belt occupying the major 
part of the geosyncline in which the rocks of the 
Chert-Spilite Formation were deposited. The 
volcanic rocks appear to be associated with a 
peridotite-gabbro-diorite association of Lower 
Tertiary plutonic rocks which occur abundantly 
in eastern North Borneo. 

Upper Tertiary and Quaternary volcanic rocks 
occurring in the Semporna and Dent Peninsula 
area have been described by Reinhard and Wenk 
(1951, pp. 31-47) and Fitch (1955, pp. 50-54) 
who considered the volcanic centres to be a 
continuation of the chain of young volcanoes 
along the Sulu arc. At the beginning of the 
Lower Miocene, small volcanic eruptions produced 
andesitic tufTite and agglomerate, interbedded 
among marine Aquitanian sediments, exposed in 
the lower River Segama, and in an outlier of 
Aquitanian rocks west of Darvel Bay. More 
extensive volcanic activity occurred in Quater- 
nary times in the Segama Valley and on Semporna 
Peninsula where olivine basalt, basalt, andesite, 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



dacite and rhyolite lavas and pyroclastic rocks 
were extruded in subaerial eruptions to form 
widely distributed plateaux, terrace features and 
valley infillings. Gaya Island east of the Sempor- 
na Peninsula, is a partially eroded volcano built 
of andesitic pyroclastic material, probably ejected 
in Quaternary times. 

REFERENCES 

Campbell, C.J., 1956, Geology of the Usun Apau 

area. Brit. Borneo Geol. Survey Ann. 

Kept., 86-120. 
van Bemmclen, R.W., 1949, The Geology of 

Indonesia, Government Printing Office, 

The Hague. 
Fitch, F.H., 1955, The Geology and Mineral 

Resources of part of the Segama Valley 

and Darvel Bay area, North Borneo. 

Brit. Borneo Geol. Survev Men}. 4. 

Government Printing Office, Kuching, 

Sarawak. 
Hailc, N.S., 1954, The Geology and Mineral 

Resources of the Strap and Sadong 



valleys, West Sarawak, including the 
Klingkang Range coal. Brit. Borneo 
Geol. Survey Mem. 1. Government 
Printing Office, Kuching, Sarawak. 

Reinhard, M. and Wenk E., 1951, The Geology 
of the Colony of North Borneo. Brit. 
Borneo Geol. Survey Bull. 1, (H.M.S.O., 
London). 

Roe, F.W., 1954, An outline of the geology of 
British Borneo. Brit. Borneo Geol. 
Survey Ann. Kept., 6-22. 

Stephens, E.A., 1956, The geology and mineral 
resources of the Kota Belud and 
Kudat area, North Borneo : Brit. Borneo 
Geol. Survey Mem. 5, Government 
Printing Office, Kuching, Sarawak. 

Wilford, G.E., 1955, The geology and mineral 
resources of the Kuching- Lund u area, 
West Sarawak, including the Bau min- 
ing district: Brit. Borneo Geol. Survey 
Mem. 3, Government Printing Office, 
Kuchinc, Sarawak. 



197 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LATE TERTIARY AND QUATERNARY VOLCANICITY 
AND STRUCTURE IN NEW ZEALAND 



G. W. GRINDLEY and H. J. HARRINGTON 

Geological Survey, Wellington, New Zealand. 

(Abstract) 



In New Zealand, two regions of upper Tertiary 
and Quaternary volcanism are separated by a 
non-volcanic region. The volcanic regions are 
comparatively stable and characterised by high- 
angle normal faulting. The non-volcanic region is 
more mobile and characterised by steep clockwise 
transcurrent faulting. 

One volcanic region occupies the north-west 
half of North Island, and is divided into three 
petrographic and structural belts striking north- 
west, and a fourth striking north-east. In the 
north-west a central basalt province is bordered 
by andesite and andesite-rhyolitc provinces. The 
western province, ranging from hypersthene to 
hornblende andesite, reached a maximum in the 
Miocene and became extinct in the Pliocene. The 
central basalt province began in the Miocene, 
culminated in the Pliocene with immense sheets 
and central-volcanoes of flood basalt, and is still 
active around Auckland city with young volca- 
noes of picritic and basanitic olivine-basalt. The 
eastern province was continuously active through 
the Miocene and Pliocene, passing through, 
probably at least two andesite-dacite rhyolite 
cycles, culminating in great sheets of ignimbrite 
and rhyolite. 

In the late Pliocene or early Quaternary, the 
north-east volcanic belt became active across the 
centre of the island, overlapping slightly the 
southeast ends of the earlier north-west belts. 
Activity has been continuous with further ignim- 
brite eruptions, rhyolite, dacite and central 
andesite-volcanocs. North-east trending graben 



structures formed between Lake Taupo and the 
Bay of Plenty by subsidence along innumerable 
active faults. These grabcns have since filled 
with pumice flows and pumiceous sediments. 
Three andesite and one rhyolite volcano are still 
active, thermal springs abound, and catastrophic 
pumice eruptions have occurred up until modern 
times. 

The north-west volcanic belts arc now tccto- 
nically and scismically stable and align with an 
older trend joining New Zealand to New Caledo- 
nia. The north-cast volcanic belt aligns with 
the Kermadec-Tonga volcanic arc and parallels 
major tectonic features developing since the 
Miocene. It is bordered on the south-east by a 
major negative gravity anomaly and coincides 
with a zone of intermediate-focus earthquakes, 
the near- vertical boundary of the deep seismicity 
coinciding with the western boundary of the 
active volcanism. Tensional-transcurrent faulting 
and post-Oligocene basins of thick marine sedi- 
mentation characterise the negative-gravity belt. 
To the south-cast a wide belt of compressional- 
transcurrcnt faulting includes most of the young 
mountain ranges of New Zealand. In the South 
Island, the volcanicity ranges from late Miocene 
to early Quaternary and lies east of the high 
mountains in the stable coastal area. The volca- 
noes are basaltic with trachytes and phonolites. 
In Foveaux Strait, the Solander Islands are 
hornblende-andesite volcanic remnants and lie 
close to the edge of the compressional belt in a 
zone of moderate seismicity. 



198 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



LEGEND 
Basaltic ^$M Andesit.c 

I Monakau Andesite Province 

I Auckland Basalt Province 

HL Coromandcl Andesite Province 

Otaqo Basalt Province 
1-8 Volcanic concentrations referred 



Axis of Kermadec Trench 




Fig. 2. Quaternary volcanics. 



199 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LEGEND 

Basaltic HI Andcsitic [JjJJ Rhyohhc 
IE Auckland Basalt Province 
IT Coromandcl Andesite Province 
TV Otaqo Basalt Province 
IT Tongariro Rhyolite-andesite Province 
21 Solander Andesite Province 



I 12 Volcanic concentrations referred 
to in text 



Axis of Kermadec Trench 




200 



Fig. 1 . Upper Tertiary volcanics. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Stresj Alignment 

Direction of PHS as indicated by 
active fault displacements 



Important faults and aliqnmcnts of 
active cones m volcanic district 



Active volcanic Zone 



Non Volcanic Reqion of 
Tronscurrent Faultmq 



Axis of Kermadec Trench 



FAULTS 
Clockwise 
Anticlockwise 



so 2s o 50 too iso 




Fig. 3. Principle horizontal stress near ground surface at present day and quaternary transcurrent faults. 



201 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Non volcomc Rtqion of 
Tronjcurrent Faulting 




202 



Fig. 4. Gravity Bouguer anomalies (Data by E.I. Robertson). 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Active Volcanic Belt 



Non Volcanic Region of 
Transcurrent Faulting 



lOOkm Average Depfn of 

IntermedJate Shocks 



Axis of Kermadec Trench 



Scale 

SO 25 O SO 100 ISO 



K>0 SO O 100 200 




Fig. 5. Seismicity (Data by G.A. Eiby). 



203 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LATE PALEOZOIC-EARLY MESOZOIC VOLCANIC ACTIVITY IN 

THE SUNDA LAND AREA 

TH. H. F. KLOMPE, J. KATILI, JOHANNAS and SOEKENDAR 

Geological Institute, Faculty of Science, University of Indonesia, Bandung , Indonesia. 



Recent fieldwork in West Central Sumatra 
has revealed that in late paleozoic-early meso- 
zoic time a volcanic -sedimentary sequence of 
strata was deposited, which was given the name 
of Silungkang Formation. 

This stratigraphic sequence is compared with 
similar volcanic-sedimentary series in Djambi, 
Malaya (Pahang Volcanic Series) and West and 
Central Borneo (Bojan and Danau Series). 

This correlation led to the assumption that the 
volcanic series of Malaya and West and Central 
Borneo and those of West Central Sumatra and 
Djambi can be grouped in two different zones of 
volcanic activity, a northern, more acid zone in 
Malaya and Central Borneo, and a southern, 
more basic zone in Sumatra. 

On account of the similarity of the Sumatra 
volcanics and their differences with those of the 
northern zone, the conclusion is drawn that the 
Djambi volcanites do not originate from Malaya, 
but they form part of an authochthonous series. 

This and the fact that nowhere in West Central 
Sumatra have any indications for thrustmove- 
ments been observed, make the occurrence of 
sheetstructures in Djambi and other parts of 
West Central Sumatra rather doubtful. 



and in the following pages J. Katili and Johannas 
give a preliminary description of this interesting 
series, which has been given the name Silungkang 
Formation. 

In his description of the Pahang Volcanic 
Series of Malaya in "The Geology of Malaya" 
Scrivenor (1931, pp. 93 and 94) concludes with 
the words: "the Pahang Volcanic Series is only 
a part of widespread volcanic rocks that are 
found in Sumatra and Borneo" and that all 
these occurrences have to be considered as 
remnants of an even greater volcanic activity in 
the late paleozoic and early mesozoic than the 
tertiary and quaternary period of volcanic activity 
in Sumatra, Borneo and Java. 

In connection with this, short surveys on the 
occurrences of the sedimentary-volcanic series 
of similar age and character of Djambi (Sumatra), 
Malaya, and Borneo (fig. 1) are given to see 
whether it is possible to come to some general 
conclusions in regard to this appearance of late 
paleozoic- early mesozoic volcanic activity in 
the Sun da Land Area. 



THE SEDIMENTARY-VOLCANIC 

SEQUENCE OF WEST CENTRAL 

SUMATRA AND DJAMBI 



GENERAL INTRODUCTION 

This paper deals with some results of recent 
field investigations in West Central Sumatra, 
where for a few years (1953-1957) students of 
the Geological Institute of the Faculty of Science 
have been preparing a geological map on a scale 
1 : 25,000 of a part of West Sumatra, known as 
the Padang Highlands. 

The fieldwork, carried out under the supervi- 
sion of the first author, has revealed the occur- 
rence of an important and extensive sedimentary- 
volcanic sequence of strata in these Highlands, 

204 



~ Introduction 

The Lasi granite mass, between Sawahlunto 
and Solok, in the Padang Highlands (West 
Central Sumatra) is bordered in the East by a 
series of sediments which are of permo-carboni- 
ferous and triassic age and which was given the 
name of Silungkang Formation, after the village 
of Silungkang where this sequence is best deve- 
loped and exposed (fig. 2). This series of strata 
is characterized by a considerable amount of 
interbedded lavas and pyroclastics, showing that 
in this area occurred in late paleozoic-early 
mesozoic time a fair amount of spasmodic 
volcanic activity. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



LATE PALEOZOIC- EARLY MESOZOIC 
VOLCANIC ACTIVITY 

IN THE 
SUNDA LAND AREA 




JT Occurrence m Sumatra 

a Padang Highlands 

b Balang Sangir 

c Djamb" 



Occurrence m Borneo 
A Tnassic 

A Permo- Carboniferous 
A Pcrmo - Tnassic 
D Type localily 



r ** Occurrence of Pahang Volcanic Series 
in Malaya 

[] Richardson's area of investigation 



Fig. 1. 



Also further southeast, in Djambi, occurs a 
series of permo-carboniferous and triassic sedi- 
ments rich in intercalations of effusives and tuffs. 

In this short account the authors will try to 
correlate the Silungkang Formation with the 
Djambi deposits of similar age and character. 
The information regarding the Silungkang For- 
mation should be considered as a preliminary 
account. It is the result of detailed geological 
mapping in the Padang Highlands and will be 
more extensively dealt with in two theses describ- 
ing the complete results of this mapping. The 
information on Djambi is obtained from publica- 



tions by Tobler (1919), Kugler (1921) and Zwier- 
zycki(1930). 

Development in the Padang Highlands 

a. Silungkang Formation. 

Though there exists no sharp boundary between 
the two sections, the Silungkang Formation can 
clearly be subdivided in two series, a lower vol- 
canic series and an upper calcareous series. 

The Silungkang Volcanic Series is mainly 

205 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



GEOLOGICAL SKETCHMAP 

OF THE 

LAS! GRANITE MASS 
Scale 1 : 250.000 





Triassic 

Pcrmo - Carboniferous 
Silungkang Formation 

Limestone intercalations 

Pyroclastics, lavas. 

Shale, marl, limestone, chert 

Slate Formation 



* * a * J Quaternary volcanic products 



Andesite (-fuff), 

Dioriteporphyrite, microdiorite, diorite 

Granite and diorite 
Migmatites 




206 



Fig. 2. 



built up of lavas and pyroclastics with interbedded 
limestones, shales, sandstones, some chert and 
silicified shales. The greenishgray to black 
volcanic rocks are hard and locally silicified, 
they are often chloritized and brittle. Also the 
interbedded normal sediments contain some 
pyroclastic material demonstrating that the vol- 
canic activity, though less intensive, was con- 
tinuing all the time. The occurrences of chert 
and silicified shales should also be ascribed to 
this occurrence of volcanic activity. During the 
paroxysmal stages mainly lavas and pyroclastics 
were deposited. 

The tuffs are fairly well cemented. They show 
a distinct porphyric structure. Towards the top 
they become lighter in colour and their porphyric 
character becomes clearer because the phenocrysts 
of plagioclase become better distinguishable. 
The tuffs are predominating the lavas and can be 
classified as hornblende dacite tuffs. 

The lavas are hornblende dacites, and micro- 
scopic examination shows that the main com- 
ponents arc hornblende and plagioclase, repre- 
sented as well by phenocrysts, as in the matrix. 
The plagioclases are of the oligoclase-andcsine 
type; epidote and chlorite occur as weathering 
products of the hornblende. 

The Silungkang Calcareous Series is chiefly 
composed of massive, fossiliferous limestones, 
sandy limestones, calcareous sandstones, marls 
and shales with interbedded agglomerates, tuffs 
and lavas. In contrast with the normal sediments 
of the Silungkang Volcanic Series those of the 
Silungkang Calcareous Series are not containing 
any pyroclastic material. Locally, e.g. South of 
Siberambang, the limestone alternates with 
agglomerates and tuffs, in other places, however, 
the tuffaceous material is considerably less. 

The effusive rocks of this Silungkang Cal- 
careous Series are represented by rather compact, 
dark coloured lavas. Microscopic examination 
shows that they are porphyric plagioclase rocks 
with phenocrysts of augite. Some plagioclases 
are of the oligoclase-andesine, some of the 
labrador type. Primary quartz is not found 
in these lavas which are augite andesites and 
-basalts. 

Regarding the volcanic activity we see that in 
the upper section of the Silungkang Formation 
more limestones were deposited and that the 
volcanic activity was far less than in the lower 
section of this formation. 



VOLUMEJ2 GEOLOGY AND GEOPHYSICS 

In the upper part more lavas were produced 
and lack of tuffaceous material in the sediments 
of this part shows that the volcanic activity was 
no longer continuous but periodic. It is also clear 
that the products of the volcanic activity changed 
from the intermediate (hornblende dacite) to a 
more basic type (augite andesite and augite 
basalt). 

As far as the age of the Silungkang Formation 
is concerned we are entirely dependent from the 
fossils of the intercalated limestones. The 
limestones in the lower section arc few and are 
in general recrystallized or silicified so that no 
fossils were preserved. Only in the upper part 
of the Silungkang Volcanic Series intercalations 
of a thin fossiliferous limestone occur. 

The limestones of the Silungkang Calcareous 
Series are very rich in fusilinids, corals, crinoids, 
gastropods, brachiopods and ammonites. Some 
of the fusilinids were determined by Umbgrove 
(van Bemmelen, 1949) who considered them to be 
characteristic for the Permian and Carboniferous. 
Marks is of the opinion that they are indicating 
an upper permian age. Until further determina- 
tions have been made the formation should be 
considered as a representative of the Permo- 
Carboniferous. 



b. Triassic. 

The Silungkang Formation is conformably 
overlain by the Triassic and also this formation 
can be subdivided in two different parts. The 
lower section is built up of a clayshale-marl 
series. The shales are locally silicified. Intercala- 
tions of andesitic tuffs and intrusions of diorite 
porphyrite, microdiorite and diorite in dykes 
and sills occur frequently. 

The upper part consists mainly of fossiliferous 
calcareous marls and marly limestones and the 
uppermost part is formed by a limestone breccia. 



J A * 

Fossils prove that these layers are of triassic 

;e. 



age 



Conditions of Deposition 

The following table shows the development of 
the Silungkang Formation and the Triassic in 
the area between Sawahlunto and Solok in the 
Padang Highlands : 

207 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



AGE 



u 

53 
in 



& 
H 



o Igz 
SS ! <2 

Sill 

AW 5:5 



SUBDIVISION 

Calcareous Section 

Shale-marl Section 



Silungkang Calcareous Series 



Silungkang Volcanic Series 



LITHOLOGY 



Fossiliferous limestones, marly limestones, calcareous 
marls, limestone breccia. 

Clayshales, locally silicified and marls. Intercalations 
of andesitic tuffs. Dykes and sills of diorite porphy- 
rite, microdiorite and diorite. 

Massive fossiliferous limestones with fusulinids, sandy 
limestones, calcareous sandstones and some clay- 
shales. 

Few intercalations of agglomerate and tuffs of the 
augite andesitic and-basaltic type. 
Several flows of augite andesite and-basalt. 

Volcanic rocks represented by hornblende dacites 
and their tuffs. Few thin intercalations of lime- 
stones, shales and sandstones, mixed with tuffaceous 
material and silicified. 



From this table we see that the sedimentation 
was accompanied by a sometimes continuous, 
sometimes periodic volcanic activity. 

In general the activity was strongest in the time 
interval of the Silungkang Volcanic Series and 
came to an end in the lower section of the Trias- 
sic. Effusive and pyroclastic rocks of resp. 
dacitic, andesitic and basaltic composition were 
the result of this activity. The conclusion can be 
drawn that sedimentation took place in the shal- 
low part of a seabasin, all sediments show a 
neritic-bathyal facies, bordered by one or more 
landareas (islands), crowned by active volcanoes. 
From time to time paroxysmal eruptions pro- 
duced enormous quantities of pyroclastics, while 
in times of normal activity normal sedimentation 
predominated. No definite proof is found that 
submarine volcanic activity occurred. 

During the period of sedimentation of the 
Silungkang Calcareous Series andesitic and basal- 
tic lavaflows were produced and predominated 
the agglomerates and pyroclastics of similar 
composition. This phenomenon and the devel- 
opment of massive reeflimestones, possibly 
bioherms, indicate that the sediments were depo- 
sited closer to the land. 

Also the sediments of the Triassic, clayshales, 
marls and wellbedded limestones, have a neritic 
to bathyal facies. The volcanic activity decreased 
considerably during the Triassic and came to a 
complete standstill in the upper section. 

During the period of deposition of the Silung- 
kang Volcanic Series the products were of a more 
acid nature (dacites) which turned more basic 

208 



during the upper part of the Silungkang Forma- 
tion and the lower part of the Triassic (andesites 
and basalts). 

Development in Djambi 
a. Pcrmo-Carboniferous 

Tobler subdivided in 1919 the Permo-Carboni- 
ferous of Djambi (fig. 1 ), more on a petrographic 
than on a stratigraphic base, in two sections and 
in 1930 Zwierzycki made a stratigraphic subdi- 
vision in three parts which were given the names: 
Karing-, Salamuku-, and Air Kuning layers. 

According to Zwierzycki the Permo-Carbonife- 
rous forms an undisturbed sequence of strata. 
The main part of it is built up of volcanic pro- 
ducts of dacitic, liparitic and andesitic composi- 
tion which were deposited during periods of 
volcanic paroxysm or as denudation products 
along a descending coast. Lavaflows are rare 
and are only found in the upper part of the 
section. 

The volcanic layers are interbcdded with 
limestones, shales and conglomerates, and parti- 
cularly the occurrence of foraminifera-limestones 
in various places points to a marine environment 
of deposition. Frequently occurring plant 
remains, bad layering and cross bedding indicate 
a littoral facies of the sediments. 

The fossil flora and fauna put the age of these 
deposits as permo-carboniferous. The fusilinids 
reach till in the upper part of the section and are, 
according to Gerth, species characteristic for the 
Permian, so that the upper part of the series is 
of permian age. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



The results of the volcanic activity are in the 
Karing layers represented by dacitic tuffs; in the 
Salamuku layers, during the deposition of which 
there was an increased activity, we find the disin- 
tegration products of liparites, silicificd dacite 
tuffs and propylized hornblende andesites; and 
in the Air Kuning layers andesitic pyroclastics 
and lavas come to the front. During this time 
interval not only the character of the products 
changed but apparently the vents were shifted in 
the direction of the sedimentary basin. The 
lavas are chiefly augite andesites, though silicified 
dacitic tuffs also occurs. 



b. Triassic 



The Triassic is well exposed in the Batang 
Sangir Area (fig. 1) and was described by Kugler 
(1931). It is represented by a complex of massive 
rccflimestones and well bedded fossilifcrous 
limestones. Thin intercalations of hornblende 
porphyrites indicate that the volcanic activity had 
decreased considerably in triassic time but was 
not yet completely extinct. 

The stratigraphy of the Permo-Carboniferous 
and Triassic in Djambi and the Batang Sangir 
Area is given in the following table: 



AGE 



SUBDIVISION 



TRIASSIC 



1 



Air Kuning layers. 



Salamuku layers. 



w Karing layers. 

CL 



So 



LITHOLOGY 

Massive reeflimestones and wellbedded fossiliferous 

limestones. 

Thin intercalations of hornblende porphyrite. 

Limestones withfusilinids. 
Augite andesitic tuffs and lavas 
Dacitic conglomerates. 

Conglomerates, breccias, sandstones; few shales and 
limestones with fusulinids. Desintegration products 
of dacites, silicified dacitic tuffs, propylized horn- 
blende prophyrite or-andesite. Upper Carboni- 
ferous flora. 

Shales, sandstones, few conglomerates, thin coallenses 
and in the upper part some limestones with fusulinids. 
Dacitic and liparitic tuffs. 
Upper Carboniferous flora. 



Conclusions 

This preliminary description of the Silungkang 
Formation and the review of the development of 
the Permo-Carboniferous in Djambi make it 
possible to draw the following conclusions: 

1. The Silungkang Volcanic Series of the Padang 
Highlands shows a great similarity with the 
Karing and Salamuku layers of Djambi. In 
both regions the sequences are chiefly built 
up of volcanic products, dacitic and andesitic 
in composition, in Djambi some volcanites of 
the liparitic type occur. Pyroclastics are more 
common than lavas. Limestones remain 
entirely in the background. 

2. The Silungkang Calcareous Series of the same 
area shows a very good correlation with the 
Air Kuning layers of Djambi. In both areas 
fusulinid-bearing limestones are predominat- 
ing. Although tuffs are not entirely absent; 



far more lavas of the augite-andesitic and 
-basaltic type were produced. 

3. Conglomerates in the Salamuku layers and the 
occurrence of plant-remains and stigmarias 
in the Karing and Salamuku layers of Djambi 
make it acceptable that at least part of these 
layers were deposited closer to, or even on the 
land, than their equivalents in the Padang 
Highlands. 

4. Also the development of the Triassic in both 
areas shows a great similarity. The Triassic is 
characterized by volcanites of andesitic com- 
position. 

5. The Silungkang Formation and the Triassic 
of the Padang Highlands are developed with 
all the same characteristics as the permo-car- 
boniferous- triassic sequence in Djambi and 
both series can very well be correlated with 
each other. 

209 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



RECENT INVESTIGATIONS ON THE 
PAHANG VOLCANIC SERIES IN MALAYA 

Introduction 

In Malaya, spasmodic volcanic activity oc- 
curred in carboniferous to triassic time and the 
name Pahang Volcanic Series was first given by 
Scrivenor (1911) to the eruptive and intrusive 
rocks of the Malaya Peninsula, which were older 
than the mesozoic granite. The Pahang Vol- 
canic Series can best be studied in Pahang, 
where good exposures are found along the Pahang 
River and its tributaries. The series is best devel- 
oped East of the Main Range; West of this range 
these rocks are only found in few small outcrops 
(fig. 1). 

The first detailed description was given by 
Scrivenor (1911). Later, Wilbourn (1917) pub- 
lished a fuller account and the same author 
contributed an article on this subject to Verbeek's 
"Gedenkboek", published in 1925. 

Towards the close of the Carboniferous a very 
thick and widespread series of limestones had 
been laid down in the area of the Malaya Penin- 
sula, accompanied by a strong volcanic activity. 
This series of limestones (Calcareous Series) 
was followed by an Arenaceous Series which was 
believed to be of triassic age. These rocks may 
represent the whole sequence from Lower 
Carboniferous to Rhaetic and the volcanic 
components represent undoubtedly an important 
manifestation of late paleozoic-early mesozoic 
volcanic activity. 

According to Scrivenor and Wilbourn the types 
of rocks belonging to the Pahang Volcanic 
Series, interbedded with the various sediments 
of the Calcareous and Arenaceous Series, can 
be grouped in: 

a. Lavas, represented by rhyolites, trachytes, 
dacites an andesites. 

b. Tuffs, represented by rhyolite-, andesite- 
rhyolite-, and andesite tuffs. 

c. Hypabyssal rocks, such as quartzporphyry 
and granophyre, porphyry, porphyrite, quartz- 
dolerite and dolerite. 

Results of recent Investigations in Pahang 

In recent time more detailed work has been 
done in areas where the Pahang Volcanic Series 
is well developed and the results of these inves- 
tigations have made it necessary to make certain 
alterations in the original conceptions on the 
Series made by Scrivenor and Wilbourn. 

210 



GEOLOGICAL SKETCHMAP OF THE AREA NORTH OF KUALA LIPIS 
(RICHARDSON 1950) 




Milts 4 3210 



U| Granite 

| | | | | Shle *d tuff (*) 




*, luff nd I.mesooel3) 
Ltmeilonr, shale *rd luff 13) 



5hle nd tuff 12) 




Tuff ID 

Shale U) 

Tuff nd >hlr (I) 



Fig. 3. 



One of these areas lies North of Kuala Lipis 
(fig. 3) and the following information is obtained 
from Richardson's Memoir on: "The Geology 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



and Mineral Resources of the Neighbourhood of 
Chegar Perah and Merapah, Pahang" (Geol. 
Surv. Dept. Memoir No. 4, Kuala Lumpur 1950). 

The stratified sediments of the mapped area 
are referred to two groups, the Calcareous Series 
and the Arenaceous Series (fig. 3). Interbedded 
tuffs, agglomerates and lavas of the Pahang 
Volcanic Series are interbedded with all the rocks 
of the Calcareous Series and are virtually absent 
from the Arenaceous Series. 

The Calcareous Series is considered to be of 
carboniferous- (?) permian age; the Arenaceous 
Scries is provisionally referred to the Triassic, 
The sedimentary rocks belong to the neritic 
environment, except some of the coarsest con- 
glomerates of the Arenaceous Series which were 
probably laid down in the littoral zone. 

Up to 1939 little was known about the strati- 
graphy of the Calcareous Series but now we know 
that three lithological facies occur in the area 
under report: an argillaceous facies, predomi- 



nantly shale; a calcareous facies, mainly lime- 
stone; and a "mixed" or "transitional" facies 
comprising of interbedded limestone and shale. 
Whereas the calcareous and argillaceous facies 
are widely developed, the "mixed" facies is 
restricted. The thickness of the Calcareous Series 
may be less than 3000-4500 meters. 

In the Arenaceous Series, also three facies can 
be distinguished: a pebbly facies, comprising 
quartzite-conglomerate; an arenaceous facies, 
including quartzite, grit and quartz schists; 
and an argillaceous facies, containing shale, 
phyllite and micaschists ; in addition there is a 
little chert. The thickness of the Arenaceous 
Series is of the order of 600-700 meters. 

In the following table the stratigraphy of the 
Calcareous Series and the various interbedded 
elements of the Pahang Volcanic Series are given 
for the area North of Kuala Lipis (The numbers 
1, 2, 3, and 4 correspond with the legend of 
% 3): 



Stratigraphy of the Calcareous Series and the Pahang Volcanic Series in the area North of Kuala Lipis 

(Richardson 1950). 

Group Lithology of the Calcareous Series and of the interbedded elements of the Pahang 
number ' Volcanic Series. 

j Shales and green, chloritic tuffs of intermediate composition. Some of them coarse 
| grained, together with subordinate agglomerates. They contain abundant fragments of 

trachyte, trachy-andesite and andesite, and in addition some rhyolite. Some types 

are predominantly andesitic. 

Massively joined, white, grey and black upper limestone, intercalated with shales and 
pyroclastic rocks, largely of intermediate composition. They are more basic than those 
of group 2. 

Shales and tuffs, and a few bands of limestone. The tuffs are rhyolite tuffs, medium to 
coarse grained; some contain fragments of trachyte, trachy-andesite and andesite. 
These tuffs are more basic than those of earlier age and form together with groups 3 a 
transitional series between basal dominantly rhyolitic tuffs (group 1) and the later 
chloritic rocks of intermediate composition of the upper group (4). 

A variable group of rocks. In the northern part of the area predominantly rhyolitic 
tuffs with a few bands of shale and limestone. Further South shales are most abundant 
and only a few bands of rhyolite tuff and limestone are present. 



There is some evidence that the Calcareous 
Series and the Arenaceous Series are not conform- 
able as was originally supposed, for the change 
in lithology from quartzites, shales and con- 
glomerates to shales and limestones containing 
interbedded volcanic rocks of the Pahang Vol- 
canic Rocks is in general abrupt. "Passage 
beds" leading from the "Older" Arenaceous 
Series into the pelitic and calcareous rocks of 



the Calcareous Series have been found in few 
places. This marked lithological break from 
coarse-grained sediments, virtually devoid of 
bedded pyroclastic rocks, to shales and lime- 
stones with many stratified tuffbeds and agglo- 
merates, indicates that important changes must 
have occurred in the area from where the sedi- 
mentary and volcanic detritus was derived, or 
in the marine basin where sedimentation was in 

211 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



progress, or in both areas. 

Richardson (1950, pp. 40-46) proposes the 
following alterations in the classical conceptions 
on the Pahang Volcanic Series as given by Scrive- 
nor and Wilbourn. The study of innumerable 
sections in which tuffs and lavas are interbedded 
with shales of the Calcareous Series is enough 
conclusive proof of the contemporaneity of 
pyroclastic and extrusive rocks with shales, 
limestones and cherts of the Calcareous Series, 
believed to be of carboniferous and ( ?) permian 
age in this region. 

In the Arenaceous Series intercalations of 
volcanic rocks are very rare. Until recently 
this series has been referred to the Triassic. 
Nowadays there exists a growing tendency to 
consider some of the series, hitherto mapped 
as Trias, as belonging to the Calcareous Series, 
which is of carboniferous and (?) permian age. 
Based on structural, and lithological evidence the 
opinion is strengthened, that the Arenaceous 



than the Calcare- 
it may be Lower 
of fossil evidence 
settled. The two 
definite data are 
Newer and Older 



Series is really more ancient 
ous Series; it is though that 
Carboniferous, but the lack 
prevents this question being 
occurrences are, until more 
obtained, indicated as resp. 
Arenaceous Series. 

There is conclusive evidence enough that the 
volcanic rocks are pre-granite, but there is not 
equally strong proof that the hypabyssal rocks 
are older than the granite. On the contrary there 
are indications that certain occurrences in other 
parts of Malaya are dated as contemporaneous 
with the granite. For this reason Richardson 
(1950) proposes that the term Pahang Volcanic 
Series should be restricted so as to include only 
those rocks which are indubitably of volcanic 
origin and also contemporaneous with the sedi- 
mentary rocks with which they are interstratified. 
So the following revised classification of the 
Pahang Volcanic Series is proposed by Richard- 
son: 



LAVAS 

Acid Rhyolite 

Intermediate Trachyte, Trachyandesite, Andesite. 



PYROCLASTIC ROCKS 

Rhyolite tuff, felspar tuff. 

Trachyte-rhyolite tuff, Trachyandesite- 

rhyolite tuff. 

Andesite-rhyolite tuff and agglomerate. 



No basic volcanic rocks are represented, for it 
is not known whether the outcrops of serpentine 
should be classed as lavas or intrusions. Accord- 
ing to the authors it is likely that these serpentines 
are representatives of an initial phase of the 
magmatic cycle connected with the formation of 
the Malayan Geosyncline out of which in meso- 
zoic time the Malayan Mountain System was 
arched up. In that case, these serpentines, 
though more or less contemporaneous with the 
Pahang Volcanic Series do not belong to this 
series. According to Stille's nomenclature (1950) 
the Pahang Volcanic Series should be considered 
as the result of subsequent volcanic activity 
in a quasi-consolidated area in connection with 
the variscian cycle of orogeny of which the 
paroxysmal zone lies further Northeast in 
Indochina and submerged in the Gulf of Siam. 

Conditions of Deposition 

As well the lithology of the layers, as the 
nature of the scanty fossils obtained from them, 
indicate, that the Calcareous Series was laid 

212 



down in a neritic environment located between 
the low-tide mark and the 100 fathom isobath ; 
the shales and mudstones in water continuously 
charged with silt; and the limestones in water 
into which relatively little terrigenous material 
was present. The alternation of argillaceous 
and calcareous rocks is a clear indication that the 
^conditions, controlling their deposition, were 
subject to rhythmic variations. The sediments 
of the Older Arenaceous Scries are also charac- 
teristic of the neritic environment with quartzites 
and conglomerates deposited in shallow water 
near the coast, and the shales in deeper water 
off-shore. 

These two series may be imconformable but 
the structure is so complex that evidence obtained 
so far is inconclusive. 

The Pahang Volcanic Series consists largely 
of rhyolite tuffs, subordinate andesite-rhyolite 
tuffs and agglomerates together with rhyolite 
and andesite lavas in a few localities. 

Although beds of contemporaneous volcanic 
rocks are confined to the Calcareous Series, 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



fragments of volcanic material occur in the quart- 
zites, grits, and conglomerates of the Arenaceous 
Series. The occurrence of such small percentages 
of volcanic material in the coarse sediments of 
the Arenaceous Series and the virtual absence 
of interbedded pyroclastic and extrusive rocks 
may be explained in two ways. Firstly, volca- 
nicity may have occurred contemporaneously with 
the deposition of the Arenaceous Series, but so 
far away, that only small quantities of volcanic 
detritus reached the basin in which it was being 
laid down; or, secondly, the volcanic detritus 
may have been derived largely from pre-existing 
volcanic rocks older than the Arenaceous Series. 
The first supposition implies that volcanicity 
was contemporaneous with the Arenaceous 
Series, the second that it was even older. Richard- 
son is of the opinion that the Arenaceous Series 
may be older than the Calcareous Series, so it is 
probable that volcanism may have been active 
at least as early as the Lower Carboniferous. 

The paucity of volcanic material in the Arenace- 
ous Series may be explained as due to the inter- 
mittent and feeble nature of the volcanicity 
characterizing the beginning during the Lower 
Carboniferous. All lavas are associated with 
neritic sediments, mainly shales and marine 
deposited pyroclastics. It seems therefore that 
some of the volcanoes from which they were 
extruded were probably located in part below 
water-level on the sea-floor, some little way off- 
shore, but the main part of them were located 
above the sea-level on smaller or larger islands 
not too far from the coast. The lavas were either 
poured out directly on to the seafloor, or flowed 
over short distances down the slopes of subaerial 
volcanoes and thence into the sea. The outpour- 
ing of lavas directly on to the seabed would 
explain why none of them is scoriaceous, why 
the enclosing sediments show no signs of contact 
metamorphism, and why the extrusive and 
stratified rocks are conformably interbedded. 
Also all pyroclastics are interstratified with 
shales and limestones of the Calcareous Series. 

The conditions of deposition of these strata 
further East, e.g. in the Kuantan Area (Eastcoast 
of Pahang) are similar to those just described. 
Here (Fitch 1952), the tuffs are bedded like normal 
submarine deposits but the rhyolitic rocks are 
in general very massive and uniform in texture. 
Several cases of banding, believed to be bedding, 
have been observed. This might have been due 
to deposition below the sea or to the falling of 
volcanic ash upon the surfaces of lava flows. 
In any case the deposition was on or near a shore 



line. Radiolarian cherts are in various places 
associated with rocks of the Pahang Volcanic 
Series and it is possible that the silica in the 
sea-water, necessary for the building up of 
Radiolarian tests, was supplied by pneumatolitic 
emanations from these eruptions. 

Conclusions 

From this synopsis the following conclusions 
can be drawn: 

1. During the Permo-Carboniferous a series of 
sediments and volcanic products were con- 
temporaneously laid down in a shallow sea 
basin. 

2. This sea basin was situated either close to 
an extensive land area or from the floor of 
this sea basin rose several smaller and larger 
islands. The land area or the islands were 
crowned with volcanoes which supplied the 
volcanic material of the sequence. 

3. In case it were islands, it is very likely that 
these were arranged in the shape of an arc. 

4. The volcanic activity was continuous but 
of a spasmodic nature; periods of paroxys- 
mal eruptions alternated with periods of low 
activity. 

5. There are lithological changes as well from 
lower to higher horizons, but also in a lateral 
sense. In the lower group rhyolitic pyro- 
clastic rocks are predominant, increasing in 
abundance northward and dying out south- 
ward. The middle group, containing a 
transitional series of rhyolitic and more 
basic tuffs and agglomerates, led on to the 
upper group which consists essentially of 
tuffs and some agglomerates of intermediate 
composition. Both groups increase in impor- 
tance southwards and die out northwards. 

6. It is clear that there was a marked decline 
in the activity of the volcanoes producing 
material dominantly of rhyolitic composition, 
and another group, producing more basic 
material (trachytic to andesitic) became 
increasingly important. 

7. In case Richardson's interpretation is correct 
that the Arenaceous Series is really older 
than the Calcareous Series, then it follows 
that the volcanicity, producing rhyolitic 
lavas and fragmental material, commenced 
feebly before deposition of the Calcareous 
Series and reached its acme during the 
Upper Carboniferous or Permian. 

8. There are no basic volcanic rocks in the 
series. The outcrops of serpentine which 

213 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



occur in several localities have to be considered 
as the representatives of the initial (ophio- 
litic) phase of a magmatic cycle connected 
with the formation of the Malayan Geosyn- 
cline out of which in mesozoic time the 
Malayan Mountain System was formed. 

9. The hypabyssal rocks, formerly included in the 
Pahang Volcanic Series, are younger than 
these volcanic products and are eventually 
related to the younger, possibly Jurassic, 
granitic invasion occurring during the forma- 
tion of the Malayan Mountain System. 

10. The permo carboniferous-triassic volcanic 
products should be considered as the result 
of subsequent volcanic activity in a quasi- 
consolidated area connected with the varis- 
cian cycle of orogeny of which the diastrophic 
zone lies furher to the Northeast in Indochina. 



DEVELOPMENT OF THE PERMO-CAR- 
BONIFEROUS TRIASSIC SEDIMENTARY- 
VOLCANIC STRATA IN WEST AND 
CENTRAL BORNEO 

Introduction 

A sedimentary and a volcanic facies can be 
distinguished in the development of the Permo- 
Carboniferous and Triassic of West and Central 
Borneo. Both are inter bedded with each other 
and are strongly dislocated by a mesozoic phase 
of orogeny. 

The volcanic components of the Permo-Car- 
boniferous are basic to intermediate in composi- 
tion, while the triassic products are of a more 
acid type. Representatives of the permo-car- 
boniferous sequence occur in the southern part 
of the area, while the triassic sequence is much 
better developed in the northern part of the area 
(fig. 1). In between lies a complicated mixture 
of both series as a result of strong structural 
movements, which Zeylmans van Emmichoven 
(1938) indicates on his map as Permo-Carbonife- 
rous-Upper Triassic. 

The basic volcanic products can very well be 
correlated with the Pulu Melaju Series of the 
Danau Formation, and the triassic sequence of 
sediments including more acid volcanics with the 
Bojan Series. 

In various localities the deposits contain 
sufficient well preserved fossils to allow an accu- 
rate age determination. 

214 



Development of the strata 

a. Permo-Carboniferous. 

Though a sedimentary and a volcanic facies 
can be distinguished in these deposits, it is not 
clear whether the sedimentary, or the volcanic 
complex forms the lower part. It is very likely, 
however, that both were deposited contempora- 
neously because basic volcanites were found as 
intercalations in the sediments. The sedimentary 
facies is represented by limestones, slates and 
phyllites, and silicified rocks such as hornstones, 
slates and jaspis. Apparently the original sedi- 
ments of the permo-carboniferous were clays. 
They contain fusulinids and plantremains, such 
as Catamites and Pecopteris. The volcanic 
products are basic intermediate to basic lavas, 
pyroclastics and breccias, usually strongly decom- 
posed. They are completely identical to the 
effusives of the Pulu Melaju Series of the Danau 
Formation. Because they are interbedded bet- 
ween the fossiliferous sediments, we know that 
they are also of permo-carboniferous age. 

b. Triassic. 

Again two different facies can be distinguished, 
but in West Borneo the proper succession of 
these is not yet known. From Central Borneo, 
however, Zeylmans van Emmichoven (1938) 
describes triassic deposits of which the lower 
section has a typical flysch facies and the upper 
part a volcanic facies. He gave this formation 
the name of Bojan Formation. Up to now no 
fossils were found but lithologically they are very 
similar to the Triassic of the Sanggau-Sarawak 
region. 

The sediments of the lower part consist of 
arkosic sandstones, coarse grained polymict 
sandstones and shales. Their facies is littoral 
Jo neritic. 

The composition of the volcanic series is 
trachytic to dacitic and consists of tuffs and 
agglomerates. Clayey and sandy tuffs, and 
tuffaceous slates show that the volcanic activity 
was continuous with, from time to time, paroxys- 
mal stages. 

Beside tuffs, also dykes, sills and lavaflows 
occur. The lavas are augite andesites, trachytes 
and granosyenite prophyries, the dykes are dacites 
and hornblende andesites. 

c. Basic intrusives. 

In the Kembajan Mts, in West Borneo, and in 
the middle Kapuas region of Central Borneo 
basic plutonic rocks occur, among which gabbro, 



VOLUME 12 



olivine gabbro, norite and gabbrodiorite can be 
distinguished. 

These basic intrusives were strongly influenced 
by the invading tonalitic intrusion in West 
Borneo, which is supposed to have taken place 
in post permo-carboniferous and prae upper 
triassic time. Fragments of these acid rocks 
are found in the clastic sediments of the Upper 
Triassic. The Permo-Carboniferous might be 
suggested as a possible age for these basic, 
ophiolitic intrusions. 

d. Triassic in Sanggau-Sarawak. 

This terrigenous series of strata consists of 
sandy claystones and finegrained claysandstones. 



GEOLOGY AND GEOPHYSICS 

and 



Conglomerates form the basal part ana are 
very widespread. Monotis and Halobia charac- 
terize these layers as Upper Triassic. The 
intercalated volcanic components of the series 
are represented by lavas, pyroclastics and agglo- 
merates of acid to acid-intermediate composition. 
Transitions into alkali-rocks (trachytes) occur 
locally. The volcanites are usually in such a 
state of decomposition that it becomes impossible 
to make out whether they have an acid or basic 
character. 

The following table gives the various rocktypcs 
of both facies of these permo-carboniferous- 
triassic strata : 



AGE 



Triassic 



Permo-Carbo- 
niferous 



SEDIMENTARY FACIES 



Flyschfacies : sandstones 
shales, tuffagglomerates. 
Fossils: Monotis, Halobia 



clay- 



Limestones, claystones, slates, 
phyllites. Silicified rocks: horn- 
stones, slates, jaspis. 
Fauna: fusulinids 
Flora : Catamites, Pecopteris. 



VOLCANIC FACIES 



Pyroclastics, locally alternating with sedi- 
j ments. Lavaflows, sills and dykes of 

acid-intermediate composition (dacite- 
I trachyte) 

j Basic intermediate to basic lavas, tuffs 
and breccias, usually completely decom- 
| posed 



Conclusions 

From this short survey the following conclu- 
sions can be drawn : 

1. During the Permo-Carboniferous a series of 
sedimentary-volcanic strata was deposited 
in which intrusions of the ophiolitic type 
occurred. 

2. In triassic time a series of strata with a flysch 
facies was deposited. This sedimentary 
series is overlain by a series of volcanic 
products of intermediate-acid to interme- 
diate composition interbedded with sediments. 

3. The basic plutonics (ophiolities) of permo- 
carboniferous age are supposed to represent 
the initial phase of an orogenic magmatic 
cycle (Pacific cycle), intruded in the basal 
permo-carboniferous strata in a subsiding 
geosyncline. 

GENERAL CONCLUSIONS 

A comparison of these synopses on the occur- 
rence of a late paleozoic-early mesozoic volca- 
nic activity in various parts of the Sunda Land 



Area and a correlation of the conclusions of 
these reviews lead to the following general 
conclusions: 

1. A permo-carboniferous-triassic period of 
strong volcanic activity occurred in various 
parts of the Sunda Land Area and resulted 
in the formation of a contemporaneously 
deposited sedimentary-volcanic sequence of 
strata. In Malaya this activity was probably 
started in the Lower Carboniferous, in 
Sumatra and Borneo in the Upper Carbonif- 
erous and lasted, though on a smaller scale, 
until the Triassic. In all described areas 
the volcanic paroxysm took place in upper 
carboniferous-permian time. 

2. The various volcanic products were supplied 
by volcanoes close to the coast of an exten- 
sive land area or on small or large islands. 
These products, their distribution, and the 
facies of the contemporaneous sediments 
suggest that at least a large part of the Sunda 
Land Area was during that period covered 
by a shallow sea in which an island archipe- 
lago existed. 

215 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



3. It is, according to the distribution of the 
various types of volcanic deposits and their 
chemical composition, not unlikely that these 
islands were grouped in two arcs, a northern 
one passing through the areas of Malaya 
and Central Borneo, characterized by acid to 
intermediate products, and a southern one 
passing through Sumatra of which the pro- 
ducts are intermediate to basic in composi- 
tion. 

4. Jn all examined areas the first volcanic 
products are the most acid ones. During 
their further development more basic rocks, 
in the northern zone of the intermediate and 
in the southern zone of a basic type, were 
produced. 

5. The late paleozoic early mesozoic volcanic 
activity in the Sunda Land Area can be 
considered as the result of a subsequent 
magmatic activity in the quasi-consolidated 
foreland of the variscian cycle of orogeny 
of which the diastrophic zone lies further to 
the Northeast in Indochina. 

6. The serpentines occurring at the base of the 
Pahang Volcanic Series and the intrusions 
of the ophiolitic rock types in the Permo- 
Carboniferous of West and Central Borneo 
are to be considered as the representatives 
of the initial phase of the magmatic cycle 
accompanying the Pacific cycle of orogeny. 
They were intruded in the base part of the 
permo-carboniferous section of the subsid- 
ing Malayan Geosyncline. Occurrences of 
ophiolites are not reported from the southern 
zone of volcanic activity in Sumatra. 

7. The hypabyssal rocks of Malaya, formerly 
included into the Pahang Volcanic Series, 
and similar occurrences of dykes and sills 
of hypabyssal rocks in the Triassic of Borneo 
and Sumatra are the result of a younger 
intrusive activity which is probably a fore- 
runner of the late mesozoic granitic invasions 
(Jurassic and cretaceous) in the Sunda Land 
Area. 

8. It was formerly accepted that the volcanic 
series in Djambi were not only similar to 
those of the Pahang Volcanic Series in Malaya 
but that they also originated from that area. 
Extensive thrust-movements were accepted 
to explain the transportation of these volca- 
nic complexes. This correlation was one 
of Tobler's reasons to accept a sheetstructure 
for a part of Djambi. 

A close comparison of the Djambi volcan- 
216 



ites with those of the Pahang Volcanic Series 
shows that this correlation is petrographi- 
cally and chemically incorrect, but that 
there exists a perfect correlation between the 
Djambi volcanics and those of the Silungkang 
Formation. 

9. Based on the differences between the Djambi 
volcanics and those of the Pahang Volcanic 
Series, the good correlation between the 
last and the Silungkang Formation, and the 
fact that during the years of fieldwork in the 
Padang Highlands not the slightest indica- 
tion was found to accept thrustmovements 
on a small or large scale, as suggested by 
Tobler, Zwierzycki, de Haan and Osberger, 
make it rather uncertain that such structures 
exist. 

10. The products of the late paleozoic-early 
mesozoic volcanic activity together with 
their contemporaneous normal sediments 
represent an autochthonous sequence of 
strata. This makes the occurrence of over- 
thrustmasses in Djambi and in other parts 
of West Central Sumatra rather doubtful. 

REFERENCES 

Alexander, J.B., 1956, Lexique Stratigraphique 
International Vol. Ill; Asie; Fascicule 
7, Malayan Archipelago; Malaya, pp. 
285-315, Paris. 

Bemmclen, R.W. van, 1939, De geologic van 
het centrale en oostelijke deel van de 
Wester Afdeling van Borneo. Jaarb. 
mijnw. Verh. 68. 

, 1949, The Geology of Indonesia, 

Vol. 1 A, Government Printing Office, 
The Hague. 

Fitch, F.H., 1952, The Geology and Mineral 
Resources of the Neighbourhood of 
Kuantan, Pahang. Geol. Surv. Dep. 
Fed. of Malaya, Memoir 6, (New) 
Series), Kuala Lumpur. 

Kugler, H., 1931, Geologic des Sangir Batang- 
hari Gebieles (Mittel Sumatra). Verh. 
Geol. Mijnb. Gen. Geol. Serie 5. 

Marks, P., 1956, Lexique Stratigraphique Interna- 
tional, Vol. Ill, Asie, Fascicle 7, Malayan 
Archipelago, Indonesia pp. 6-242, Paris. 

Molengraaff, G.A.F., 1900, Geologische verken- 
ningstochtcn in Centraal Borneo. Ams- 
terdam. 

Richardson, J.A., 1950, The Geology and Mineral 
Resources of the Neighbourhood of 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Chegar Perah and Merapoh, Pahang. 
Geol. Surv. Dept. Fed. of Malaya, 
Memoir 4, (New Series), Kuala Lumpur. 

Scrivenor, J.B., 1911, The Geology and Mining 
Industries of Ulu Pahang. Kuala 
Lumpur 1911. 

, 1925, Summary of the geological 

History of British Malaya and British 
Borneo. Gedenkboek, Verbeek, pp. 
441-447. The Hague. 



., 1931, The Geology of Malaya. 
Millan and Co., London. 



Mac 



Stille, H., 1950, Der "subsequente" Magmatis- 
mus. Abhandlung zur Geotektonik 
No. 3, Akademie Verlag Berlin. 

Tobler, A., 1919, Djambi verslag. Uikomsten 
van Geol. Mijnb. onderzoek in de 



Residentie Djambi, 1909-1912. Jaarb. 
Mijnw. Verh. Ill, met atlas. 

Wilbourn, E.S., 1917, The Pahang Volcanic 
Series. Geological Magazine, pp. 447- 
462 and pp. 503-514. 

_ , 1925, The volcanic Rocks of the 

Malay Peninsula and a comparison with 
their equivalents in the surrounding 
countries. Gedenkboek Verbeek pp. 
601-616. The Hague. 

Zeylmans van Emmichoven, C.P.A., 1938, Korte 
schets van de geologic van Centraal 
Borneo. De Ingenieur v. Ned. Jnd. 
5: (9). 

Zwierzycki, J., 1930, Die geologischen Ergeb- 
nisse der palaeobotanischcn Djambi- 
Expedition 1925. Jaarboek Mijnw. Ned. 
Ind. 1930, Verh. II. 



217 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



THE TECTONIC SETTING OF THE TONGARIRO VOLCANOES, 

NEW ZEALAND 

D. R. GREGG 

New Zealand Geological Survey, Department of Scientific and Industrial Research, Christchurch, New Zealand. 



The Tongariro volcanoes, which form the Ton- 
gariro National Park, lie at the southern end of 
the volcanic belt that extends north-east through 
the centre of the North Island of New Zealand. 
The central part of the volcanic belt was described 
by Grange (1937). All the active volcanoes, 
boiling springs, and geysers of New Zealand are 
found along this line, which was described by 
Dieffenbach (1843: p. 358) as 'one connected 
hearth of volcanic action', and called by von 
Hochstetter (1864: p. 92) the Taupo Zone. Active 
faulting is widespread in the Zone, and earth- 
quakes of intermediate focal depth are common. 
If this line of volcanic activity is projected to the 
north beyond White Island, the active volcano 
in the Bay of Plenty, it will pass through the 
volcanoes of the Tonga and Kermadec Islands. 
The Tongariro volcanoes, which include the three 
main volcanic edifices, Tongariro, Ngauruhoe, 
and Ruapehu, stand at the southern end of this 
belt of volcanism that stretches for a thousand 
miles across the south-west Pacific (Fig. 1). 

The lavas of the Tongariro volcanoes have been 
described as predominantly hypersthene-andesites 
and basalts (Grange and Williamson, 1930, 1933; 
Battey, 1949: p. 393-4). The few chemical ana- 
lyses available show, however, that on the classi- 
fication proposed by Rittmann (1952) they may 
be closer to dacite and labradorite-dacite. In- 
clusions of older rocks are very abundant in the 
recent lavas of Ngauruhoe (Battey, 1949: p. 
394-5). 

The basement rocks in the Tongariro area are 
Mesozoic greywackes and argillites of Wellman's 
(1952) alpine fades. They form the high Kai- 
manawa Mountains to the east of the volcanoes 
and lower mountains to the west. The basement 
rocks are overlain in places by pre-volcanic 
Tertiary marine sediments. The Quaternary 
volcanics rest on either the Mesozoic or Tertiary 
sediments. Generalised contours have been 
drawn on the basement surface (Fig. 2). These 
are based on observed heights of basement out- 
crops and on estimated depths to basement de- 
rived from gravity measurements made by the New 
Zealand Geophysical Survey. The estimates 
are preliminary and are based on approximations 

218 



involving uncertainties in the heights of the 
stations, in the densities of the rocks, and in the 
regional gravity values. Density values of 2.62 
for basement and 2. 1 5 for covering strata have 
been used. The estimates are considered to be 
minimum values. There is little evidence for the 
basement contours in the areas covered by thick 
volcanics, and the low near Roto Aira has been 
tentatively connected with that to the south of 
Ruapehu. 

Ruapehu erupted last in 1945, when Crater 
Lake was displaced by lava (Cotton, 1946). 
Ngauruhoe is the most continuously active vol- 
cano in New Zealand, and in its last major erup- 
tion, in 1954-55, discharged some 6,000,000 cubic 
metres of lava (Gregg, 1956). Te Mari, a crater 
on the northern slopes of Tongariro, was last 
active in 1896 when it threw out large quantities 
of ash and rock (Friedlaender, 1899: 500-2). 
Red Crater, another vent on Tongariro, was 
probably in eruption in 1855 (Hochstetter, 1864: 
100). Great rhyolitic ash eruptions have origi- 
nated near Lake Taupo, some 20 miles north of 
Tongariro, during the last few thousand years 
(Baumgart, 1954). 

The main volcanic vents of the Tongariro 
volcanoes lie in a straight line running north- 
north-east (Figs. 2, 3, 4). This remarkable line- 
arity was first pointed out by A.P.W. Thomas 
(1889: 346-7). On both sides of this line, and 
running parallel to it, are many faults showing 
fc recent displacements of small amplitude (Fig. 5). 
Some of these faults were mapped by Grange, 
Williamson, and Hurst (1938), and more have 
been found by the examination of air photo- 
graphs. Many must have been buried by recent 
eruptions. Most of the fault traces do not extend 
for more than a few miles, and almost all are 
downthrown towards the volcanoes. In the few 
cases where the dip of the fault plane has been 
determined, the faults are normal. No definite 
horizontal displacement has been detected. 

The Tongariro area thus forms the southern 
end of the Taupo Graben (Fleming, 1952). 
Fleming (1953: 298) has postulated that the 
Wanganui Basin, a region of thick late Tertiary 
and Quaternary marine sedimentation, is a 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




Fig. 1. 



219 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



175 3O'E 



39 S 



Hot springs 

o Gravimetric station* 



() Recently active volcanic vents 



Recent fault Traces 



Mesozoic greywocke at surface 

Generalised contours on qreywocice basement at lOOOft intervals 



Heiqhts ore in relation to sea level 
Scale 




220 



Fig. 2. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



N ; 




Fig 3 The Tongariro volcanoes from the north, showing the alignment of volcanic vents. Snow-capped Ruapehu is 
in the background with the prominent cone of Ngauruhoe in the centre of the photograph. Te Man craters are in 
left foreground with a recent lava flow reaching down to forest in right foreground. On the right the white scar 
of Ketetahi hot springs shows on the slopes of the North Cone of Tongariro. 

Photo. V.C. Browne. 



continuation of this graben, as was first suggested 
by Rev. Richard Taylor (1855: 223). Normal faults 
striking north-cast have been found near Wanga- 
nui (Fleming, 1953: 90), and Wellman (1955) 
pointed out that the well-defined active normal 
faults of the North Island are confined to a narrow 
belt from Wanganui to the Bay of Plenty. Park 
(1910: 262) drew his rather hypothetical 



EXPLANATION 

Fig. 1. Map of South-west Pacific, showing active vol- 
canoes. Bathymetry from N.Z. Oceanographic 
Institute; Raitt, Fisher, and Mason (1955); and Ad- 
miralty Chart No. 780. Volcanoes from Thomson 
(1926), and Gutenberg and Richter (1949). 

Pig. 2. Map of Tongariro area, showing volcanic vents, 
fault traces, and basement contours. 



Whakatane Fault along the same line. 

The linearity of the vents of the Tongariro 
volcanoes suggests that they are underlain by 
some kind of deep-seated fracture. To explain 
the petrogenetic relationship of the rocks of the 
Taupo Zone, Professor R.H. Clark, Victoria 
University College, Wellington, has postulated 
a clockwise transcurrent fault underlying the 
Zone (in a paper presented to Section C of the 
32nd Meeting of the Australian and New Zealand 
Association for the Advancement of Science, 
Dunedin, January 1957). The direction of great- 
est horizontal stress in the Taupo Zone has been 
considered to be north-east and parallel to the 
normal faults (Wellman, 1954, 1955), but if Clark's 
suggestion is correct, the stress pattern at depth 

221 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Pi g> 4. Ngauruhoe and Tonganro from the south-west. Ngauruhoe in the cone near the centre 01 pnorograpn, wnich 
is taken from above Ruapehu. Young lava flows from a vent on the north flank of Ruapehu are in the right fore- 
ground. Lake Taupo is in background. 

Photo. Whites Aviation Ltd. 



would be the same as in Wellmarf s transcurrent 
zone with the direction of greatest horizontal 
stress running east-west. 

It had early been suggested that subsidence in 
the Taupo area was a direct result of the discharge 
of large volumes of volcanic ash (Taylor, 1855: 
226). The weight of the volcanoes themselves 
would add to the effect of the withdrawal of 
material from below and the stress pattern at the 
surface would be modified by this increased 
vertical stress. There is evidence, however, that 
a tectonic basin was in existence before the main 
eruptions took place (Grange, 1937: 47), and 
certainly the co-axial Wanganui Basin was form- 
ing long before the most intense volcanism. 
Fleming (1953: 298-300) discussed the relation 
of the Taupo Zone to the Wanganui Basin and 

222 



concluded that the South Island alpine geanticline, 
the Wanganui Basin, and the Taupo Zone were 
segments in a single zone of crustal weakness. 

ACKNOWLEDGMENTS 

Thanks are expressed to the Superintendent of 
New Zealand Oceanographic Institute for pro- 
viding bathymetric data, to the Director, Geo- 
physics Division, for permission to use the pre- 
liminary estimates of depths to basement, and to 
Mr. F.E. Studt for discussion of these estimates. 

REFERENCES 



Battey, M.H., 1949, 
Ngauruhoe. 
3: 387-95. 



The Recent Eruption of 
Rec. Auck. Inst. Mus., 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



J*. 




Fig. 5. Ngauruhoe, on right, and Tongariro, viewed from the north-west. Several fault traces can be seen on the side 
of Tongariro. Ketetahi hot springs are at extreme left. Young lava flows show clearly on the cone of Ngauruhoe. 

Photo. Whites Aviation Ltd. 



Baumgart, I.L., 1954, Some Ash Showers of the 

Central North Island. N.ZJ. Scf. 

Tech. 35: 456-67. 
Cotton, C.A., 1946, The 1945 Eruption of Rua- 

pehu. Geogr. /., 107: 140-3. 
Dieffenbach, E., 1943, "Travels in New Zealand." 

John Murray, London. 

Fleming, C.A., 1952, White Island Trench, a 
Submarine Graben North-east of New 
Zealand. Proc. 7th Padf. ScL Congr., 
3:209-11. 

._ , 1953, The Geology of the Wanganui 

Subdivision. N.Z. Geol. Surv. Bull, 
n. s. 52. 

Friedlaender, B., 1899, Some Notes on the Vol- 
canoes of the Taupo District. Trans. 
N.Z. Inst., 31:498-510. 



Grange, L.T., 1 937, The Geology of the Rotorua- 
Taupo Subdivision. N.Z. geol. Surv. 
Bull.\ n.s. 37: 138 pp. 

Grange, L.I., Williamson, J.H., 1930, Tongariro 
Subdivision. N.Z. geol. Surv. 24th 
annu. Rep. n.s.: 10(3). 

, 1933, Tongariro District. N.Z. geol. 

Surv. 27th annu. Rep. n.s.: 18-21. 

Grange, L.T., Williamson, J.H., Hurst, J.A., 1938, 
Geological Maps of Tongariro Subdivi- 
sion, to accompany N.Z. geol. Surv. 
Bull n.s., 40 (text not published). 

Gregg, D.R., 1956, Eruption of Ngauruhoe 
1954-55. N.ZJ. ScL Tech., 37: 675-88. 

Gutenberg, G., Richter, C.F., 1949, "Seismicity 
of the Earth and Associated Phenome- 

223 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



na." Princeton University Press, 

Princeton. 
Hochstetter, F. von, 1864, Geologic von Neu 

Seeland. Novara-Exped., Geol. theil, J 

(1): 
Park. J., 1910, 'The Geology of New Zealand." 

Whitcombe and Tombs, Christchurch. 

488 pp. 

Raitt, R.W., Fisher, R.I., Mason, R.G., 1955, 
Tonga Trench. Geo. Soc. Amer. spec. 
Pap. 62:237-54. 

Rittmann, A., 1952, Nomenclature of Volcanic 
Rocks. Bull volcan. ser. II. 12: 75-102. 

Taylor, R., 1855, "Te Ika a Maui or New Zea- 
land and its Inhabitants." 1st ed. Wer- 
theim and Macintosh, London. 

Thomas, A.P.W., 1889, Notes on the Geology 



of Tongariro and the Taupo District. 
Trans. N.Z. Inst'21: 338-53. 
Thomson, J.A., 1926, Volcanoes of the New Zea- 
land-Tonga Volcanic Zone. A Record 
of Eruptions. N.Z.J. Sci. Tech., 8: 
354-71. 

Wellman, H.W., 1952, The Permian- Jurassic 
Stratified Rocks (of New Zealand). 
Proc. 19th Int. Geol. Congr. Symp. Gond- 
wana Ser. : 1 3-24. 

, 1954, Stress Pattern controlling Lode 

Formation and Faulting at Waihi Mine 
and Notes on the Stress Pattern in the 
North-western part of the North Island 
of New Zealand. N.ZJ. Sci. Tech., 36: 
201-6. 

, 1955, New Zealand Quaternary Tec- 
tonics. Geol. Rdsch. 43: 248-57. 



224 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



SOME CONSIDERATIONS ON THE RELATION BETWEEN CHEMICAL 

CHARACTER AND GEOGRAPHICAL POSITION OF 

THE VOLCANIC ZONES IN JAPAN 

TOSHIO ISHIKAWA and YOSH1O KATSUI 

Department of Geology and Mineralogy, Faculty of Science, Hokkaido University, Sapporo, Japan 



Pleistocene and recent volcanoes in Japan 
and Kurile Islands have been generally classified 
geographically into those of the Tisima (Chishi- 
ma), Daisetu, Nasu, Tyokai (Chokai), Huzi 
(Fuji), Norikura, Daisen and Ryukyu volcanic 
zones from the northeast to the southwest. (Fig. 1 .) 

Volcanoes which are arranged on the Kurile arc 
from Alaid at the northeastern end of the Kurile 
Islands to Daisetu and Tokati in the central part 
of Hokkaido, were formerly included in the Tisima 
zone. The western part of the above zone or the 
volcanic range running in NNE direction in 
central Hokkaido was called the Daisetu volcanic 
zone from the petrological viewpoint by the 
authors (Ishikawa T., Katsui, Y. and Suzuki Y., 
1952) since 1950, though it had been already dis- 
tinguished as the Tokati volcanic chain geograph- 
ically by some geologists. The lavas contain 
often hornblende as well as pyroxene and olivine, 
and are chemically more alkalic than those of 
most other volcanoes of the Tisima zone, which 
are petrographically pyroxene andesite and dacite 
or basalt of tholeiitic magma origin. Only Alaid 
and its parasitic volcano, Taketomi arc made up 
of slightly alkaline olivine basalt comparatively 
rich in K 2 O (Kuno, 1935) and locate distinctly 
at the west or inner side of the Tisima zone. 

The Nasu volcanic zone which starts from west- 
ern Hokkaido and extends to central Honsyu 
comprises volcanoes mostly made up of pyroxene 
andesite and dacite, and rarely basalt or tholeiitic 
magma origin. But the lavas from several vol- 
canoes at its south part contain often hornblende 
and are slightly more alkalic than those from 
other volcanoes of this zone. Risiri, a volcanic 
islet off the most northwestern coast of Hokkaido 
is built of pyroxene andesite and slightly alkaline 
basalt comparatively rich in Na 2 O. Shokanbetsu, 
a large dissected strato- volcano on the coast of 
Japan Sea, to the south of the just-mentioned 
volcano, is made up of hornblende pyroxene 
andesite and olivine basalt comparatively rich in 
alkalies. These volcanoes lie both on the 
extension Line of the Nasu zone to the north and 
have been included in it by some researchers. 
But they seem not to belong to the Nasu proper 



zone from the petrological viewpoint. The 
authors will indicate them here as volcanoes of 
the northern subzone of the Nasu zone. 

Volcanoes arranged parallel to the Nasu zone 
at the west or inner side of Honsyu arc are in- 
cluded in the Tyokai zone. It starts from Oshima- 
oshima, a volcanic islet off the most southwestern 
coast of Hokkaido and runs near the coast of Japan 
Sea to central Honsyu. The lavas from volcanoes 
belonging to it are hornblende andesite, pyroxene 
andesite and olivine basalt of alkalic olivine 
basalt magma origin, being far different petrolog- 
ically from those of the Nasu zone. 

The Huzi zone which comprises the volcanoes 
within the Fossa Magna region and those on the 
Izu Islands, running in NNW direction, is divided 
into two subzones by Kuno (1952). The southern 
subzone comprises the volcanoes south of Hakone, 
which are made up of tholeiitic basalt and pyro- 
xene andesite. While the northern subzone, 
which starts from Kozu-sima among the Izu 
Islands, and extends to the Japan Sea coast 
passing the west side of the north end of the south- 
ern subzone, comprises volcanoes built of horn- 
blende andesite, hornblende dacite and horn- 
blende or hornblende biotite rhyolite as well as 
pyroxene andesite and basalt. The basalt is 
slightly more alkaline and less siliceous than that 
from the southern subzone. I6-zima Islands 
located near the south end of the Huzi zone are 
built of trachy-andesite, and run nearly parallel 
to it at its west-side, constituting I6-zima zone 
independent of the Huzi. 

To the west of the Fossa Magna region, several 
volcanoes capping the so-called Japan Alps 
constructs the Norikura zone running in NNE 
direction. Their lavas are mostly hornblende 
andesite, biotite andesite and pyroxene andesite. 
This zone seems to be geographically the inner 
zone of the Huzi. 

The Daisen zone which runs along the Japan 
Sea coast in southwestern Japan and extends 
to Unzen at the west part of Kytisyu, is petro- 
graphically characterized by biotite hornblende 
andesite and dacite. 

225 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



\ti^Tisima(-Chi3hima) volcanic zone 



Ib western subzone of 
volcanic zone 
(Doi&etiu volcanic zone) 




FORMOSA 



lutth Jiruj/y*.fa[ td( 



'olcanic zone 

]J C South port of Nasu volconic 
zone 

lid A Tyokoi(ChokJai) volcanic zone 

ffl a Northern sub*one of 

Huzi(Fuji) volcanic zone 

JUb O Southern subzone of Hvzi ""* 
volcanic zone 

Tile. A lo-zime volcanic rone 
IVa A Norikuro volcanic zonm 
fVb Doisan volcanic zone 

IV C Northern frt of the Ry&yj 
volconic zone 

IVd* Southern part of the Ryukyu 
volcanic zone 

J-firr/f-, and ofh.fr nafk^ show volcanoes 



Fig. 1. 



The Rytikyti zone starts from Aso lying in the 
middle of Kyusyti and runs to the SSW including 
Sakura-zima and volcanoes arranged at the inner 
or west side of the main arc of Ryukyu. Volca- 
noes belonging to this zone are mostly built of 
pyroxene andesite, but the lavas from those at 
its northern part contain sometimes hornblende. 
Volcanoes lying at the north end of Formosa, 
on the extension line of this zone to the south, 
are made up of pyroxene andesite and biotite 
226 



hornblende andesite, and are located on the inner 
or west side of this zone. 

Volcanic rocks from Japan were chemically 
examined early by Yamada (1930), and the aver- 
age chemical compositions of rhyolite, rhyolite- 
andesite, andesite, andesite-basalt and basalt were 
calculated respectively. Tomita (1935) studied 
on the chemical compositions of the Cenozoic 
alkaline suite of the circum Japan Sea region and 
cleared chemical characters of alkalic rocks in 



Japan. Iwasaki collected 603 analysis of volcanic 
rocks from Japan and calculated the average 
chemical compositions of rock groups classified 
according to SiO 2 contents respectively (Iwasaki, 
1937a). Furthermore he studied the lavas of each 
volcanic zone in Japan in detail (Iwasaki, 1937b). 
Taneda (1951) examined particularly the chemical 
compositions of the lavas from volcanoes in Japan 
and discussed on the chemical characteristics of 
every volcanic zone. Ishikawa (1952), one of the 
authors, compared the chemical compositions of 
the lavas in Niggli's value calculated from them, 
especially al-alk, qz, alj al-alk and c-(al-alk) values 
corresponding to si and k-mg relation. 

According to him the lavas from volcanoes of 
Tisima, Nasu and Huzi zones are mostly higher 
in al-alk and qz values than the average of the 
young volcanic rocks of the Pelee Lassen-Peak 
type which is the highest in the above values 
among all types of the North American Cordillera. 
(Burri, 1926). As the more alkalic rocks are the 
lower in (al-alk) and qz values, the above three 
zones in Japan are considered to be of the most 
calcic type in the world. It is interesting also that 
large crystals of anorthite have often been found 
in the lavas or as crystal lapillis from the above 
zones or in Tertiary volcanic rocks constituting 
their basement and never reported from other 
districts. Ishikawa (1951) suggested from the 
above occurrence that the formation of the large 
anorthite may be due to magmatic assimilation of 
sedimentary rocks rich in A1 2 C>3. The lavas 
from the Daisen and Ryukyu zones are generally 
lower in al-alk and qz values than the average of 
volcanic rocks of the Pelee Lassen-Peak type, 
proving to be more alkalic. Katsui (1953, 1954 
and unpublished) analyzed some lavas from 
Tyokai and Daisetsu zones and from Rishiri 
and Syokan volcanoes, and studied the chemi- 
cal characteristics of the above zones or vol- 
canoes. 

Comparing the chemical compositions of the 
lavas from all the volcanic zones in Japan in Nig- 
gli's values, the authors (Ishikawa and Katsui, 
1955) noticed that the lavas of the inner most 
zone or subzone are the most alkalic. Ac- 
cordingly the authors now classify the volcanoes 
in Japan and the Kuriles into the following zones 
and subzones ; 

I. Volcanoes on the Kurile arc 
la. Tisima volcanic zone 
Ib. Western subzone of the Tisima vol- 
canic zone or Daisetu volcanic zone 



12 GEOLOGY AND GEOPHYSICS 

Ic. Inner subzone of the Tisima volcanic 

zone 
II. Volcanoes on the northern HonsyQ arc 

Ila. Northern subzone of the Nasu vol- 
canic zone 

lib. Nasu volcanic zone 
lie. South part of the Nasu volcanic zone 
lid. Tyokai volcanic zone 

III. Volcanoes within the Fossa Magna region 
and on the Izu, Bonin and I6-zima islands. 
Ilia. Northern subzone of Huzi volcanic 

zone 
I lib. Southern subzone of Huzi volcanic 

zone 
I He. Id-zima volcanic zone 

IV. Volcanoes of southwestern Japan 

IVa. Norikura volcanic zone 

IVb. Daisen volcanic zone 

I Vc. Northern part of Ryukyu volcanic zone 

IVd. Southern part of Ryukyu volcanic zone 

The above zones and subzones distribute geo- 
graphically as shown in Figure 1. The available 
chemical analysis of the lavas from volcanoes in 
Japan, selected by the authors for the present 
study totalled 441 ; their numbers from each 
volcano and zone are shown in Table I. 

The chemical compositions represented in 
oxide form were calculated into Niggli's value 
and compared with one another in qz, al-alk and 
c- (al-alk) corresponding to si and mg-k relation 
as shown in figures 2 to 5. For comparison, 
also average values of young volcanic rocks in 
Japan (Taneda, 1951) and alkalic volcanic rocks 
in circum Japan Sea region (Tomita, 1936) are 
shown in each figure. 

In figures 2 and 3, numbers of the lavas plotted 
above and on the line showing the average of 
volcanic rocks in Japan were counted in every 
zones or subzones, as shown in Table II. 

As shown in figure 2 and Table II, the lavas 
from the la, lib and II Ib zones are mostly higher 
in qz than the average value of volcanic rocks in 
Japan. He, Ilia and IVd zones are next to above 
three inqz. While the lavas from lllc, lid, Ila, IVa, 
Ic, Ib, IVb and IVc zones are generally lower in 
qz than the average. Especially IIIc or I6-zima 
zone is exceptionally low in qz and very near to 
the average of alkalic volcanic rocks in the circum 
Japan Sea region. Also in comparison of 
(al-alk) value, la, lib and Illbz ones are higher 
than the average of volcanic rocks in Japan. The 
third zone is not very much higher than the average, 
but it is distinctly higher than the Pelee Lassen- 
Peak type (Ishikawa, 1952). He, Ilia, IVc, IVd 

227 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



IbMfa/r/> sutuomot Tisima x** 
A Ic Inner StAtont of Tisim* goat 




ID a Norton subrone of Hun rone 
O IHb Southern auiuor* of Htai am 
iVSic, 16-zimo zone 




DaAbrflbm sulaene of New torn 
oDb#s** 

flc&M/M part of Nasu zot 




We Northern pert of KyukS font 
9 IVd Southern pert of Ryuku nnt 




Fig. 2. Variation diagrams of qz values corresponding to 51. The full line shows the average value of young volcanic 
rocks in Japan, and the dashed line that of alkalic volcanic rocks in the circum Japan Sea region. 



and IVb zones are next to the above three and 
near to the average. While IIIc, lid, Ha, IVa, Ib 
and Ic zones are lower in (al-alk) value than the 
average. Especially IIIc is remarkably low in 
(al-alk) as such in qz. 

As the more alkalic rock group is the lower 
either in qz or in (al-alk), as already stated by 
Ishikawa (1952), the descending order of zones 
in the above values may represent gradual change 
from more calcic to less calcic characters. Among 
volcanoes on the Kurile arcs, the Tisima zone is 
the most calcic, and the more inner and western 
zones are rather alkalic. On the northern Honsyti 
arc, the Nasu zone is the most calcic in chemical 
character, and the Tyokai zone and the northern 
subzone of the Nasu are more alkalic. Volcanoes 
at the southern part of the Nasu zone are more 
alkalic than the Nasu and near to the northern 

228 



subzone of the Huzi zone, with which they join 
geographically at the southern end. Of volcanoes 
within the Fossa Magna region and on the Izu, 
Bonin and I6-zima Islands, the southern subzone 
is the most calcic, and the northern subzone run- 
ning at its inner side is rather alkalic. The lavas from 
the I6-zima Islands are remarkably alkalic, and 
seem to constitute the inner subzone of the Huzi. 

In general the above three geographical units, 
the volcanoes of the outer side are more calcic 
than those of the inner side in chemical character, 
and thus the zonal arrangement of volcanoes with 
calcic to more alkalic lavas from the southeast 
to the north-west is well shown. To the outside 
of the most calcic zone, Japan trench, more than 
8,000 m in depth, lies as shown in figure 1, and 
seems to suggest that the magmatic character of the 
volcano is closely related to its tectonic position. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 




-ate- 






pi g> 3. Variation diagrams ot al-alk values correspond- 
ing to ji. The full line shows the average value of 
young volcanic rocks in Japan, and the dashed line 
that of alkalic volcanic rocks in the circum Japan 
Sea region. 

High qz value corresponding to si suggests the 
existence of free silica as quartz, tridymite and 
cristobalite in mode. In andesite and basalt of 
calc-alkalic type in Japan, richness in qz or Norm 
Q is generally represented in the form of silica 
minerals in the groundmass or as glass containing 
excess silica. 

al-alk Value is related to anorthite content of 
plagioclase in mode. Plagioclases in calc-alkalic 
volcanic rocks in Japan are mostly more calcic 
than those from other countries in the world. 
Large anorthite crystals which have been often 



D CSovUi p*t of /W54/ r 



n 



ID AbwW iJuow of Hug,* 




IV 



Fig. 4. Variation diagrams of c-( al-alk) values corre- 
sponding to 5i. The full line shows the average value 
of young volcanic rocks in Japan, and the dashed line 
that of alkalic volcanic rocks in the circum Japan 
Sea region. 

found in volcanites of the Tisima and Nasu 
zones and the southern subzone of the Huzizone, 
whose lavas are rich in (al-alk), are genetically 
related to the magmatic character. The more 
calcic type is generally the higher in qz or (al-alk) 
value. 

C- (al-alk) value is related to the lime content 
in pyroxene in mode. Accordingly the low value 
of c- (al-alk) suggests richness in rhombic pyro- 
xene in mode. Pyroxene andesite and basalt 
rich in hypersthene are considered to be very low 
in c- (al-alk) value. Numbers of the lavas below 

229 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



and on the lines show the average value of 
volcanic rocks in Japan and that in the circum 
Japan Sea region are shown in Table III. The lavas 
from la and lib zones of most calcic type are 
mostly plotted below the average line of volcanic 
rocks in Japan. And IIIb, Ilia, lie and IVc 
zones are low in c-(al-alk) value next to them. 
While the lavas of IIIc, Ila and IVa are mostly 
higher than the average line or more alkalic in 



O la7/5/me Jone 

I bUbstern suteot* of Tisimo zone 
\ A I tl**r *A*or* of TtSimo font 



- \N 



magmatic character, lid, Ic, Ib and IVd zones 
are comparatively high in c(al-alk) value next to 
the above three. 

From the k-rng relation diagrams (figure 5), 
numbers of the lavas plotted below and on the 
lines representing the average values of volcanic 
rocks in Japan and in the circum Japan Sea region 
were counted as in Table IV. Most lavas of la. 
lib and Illb zones are below or at the left side of 



^ 

^ 



III 3 Norhmsuhzofte fl/ Hufi Jfanf 
O ffl bSw/Mam subont of Hu*tor* 
A ID C 16 -lime zone 



\ : l. 

\ v 



m 



K ' 





. A IV aAbr/^//w AMT 


-r " '. 


* * V 7 






" 

\ 


j ^^UdS^^/r#</^a<i/2*ir 


.x ~| ' \\ 

- OcjS,*, , .!' 


\ ) 
*_>-J * 




* x I* 


/^^""Ss v i* 


Vui> is./ . 


c- * *|otfff \> * ' ^ 


.*v\ . 




t V V 


\ 0\V 


i *NW ^x* 


* o\. *"". 




oo \ ^ 


^w X 

^^W M 1 


^ ' % * * \ mEaMrttxmstjkoneoftosu*** J 


"1 
1 


1 II \yNasu zone 




1 


af c 1 11 CSWA par I of Nosu zone 


Q.? 


1 


* 1 AU CJ 7/o4<?/ /o/)/> 




M 


L 




K 


\ 




\ 


a/- \ 

n 


Of 


w * V 


...,,, ,_ , 


' V; 1 / ' ' ' 'd'>' ' ' ' a*' ' ' ' ^ a* 1 ' ' '' 



Fig. 5. Variation diagrams of mg-k relation. The full line shows the average value of young volcanic rocks in Japan, 
and the dashed line that of alkalic volcanic rocks in the circum Japan Sea region. 

230 



VOLUME 12 



the average line of volcanic rocks in Japan. 
Especially I lib zone show the lowest value ranging 
from 0.02 to 0.17 in k, though mg is variable 
between 0.07 and 0.60. The above three zones 
are of the most calcic type also from qz or (al-alk) 
value. The lavas from lllc and Jc zones are 
mostly plotted below the average line, but the 
former zone comprises volcanoes made up of 
alkalic rocks rich in Na2O and the latter consists 
of slightly alkalic basalt. Ilia, IVd and lie zones 
include more lavas above the average line than 
those below it respectively. 

While the lavas from lid, IVb, IVc, IVa and Ib 
zones are mostly above or at the right side of the 
average line of volcanic rocks in Japan, and not 
a few lavas from the former three are even above 
the average line of volcanic rocks in circum Japan 
Sea region. Accordingly each zone is chemically 
characterized by k-mg relation, and concentration 
area and arrangement are also significant to 
consider the trend of magmatic differentiation. 

Structurally, the geological units arc distributed 
zonally in the Kurile arc or in the northern 
Honsyti arc from the west or the inner to the east 
or the outer sides as follows (Minato, M, Yagi, 
K, and Hunahashi, M., 1956); 

(1) Japan Sea basin or Okhotsk Sea basin 

(2) Inner zone with volcanic belt 

(3) Outer zone 

(4) Pacific ocean basin surrounded by the 
Japan trough. 

Quaternary volcanoes arc distributed only in 
the inner zones of the above arcs where the so- 
called green tuffs are distributed widely. Minato 
and his collaborators stated that Quaternary 
volcanoes have been formed upon uplifted 
green tuff regions. 

From the result obtained by the authors, it is 
concluded that, among Quaternary volcanoes 
formed in the inner zone, those made up of more 
calc-alkalic lavas are arranged on the outer side. 
Rittmann (1953) studied already the magmatic 
character and tectonic position of the Indonesian 
volcanoes, and stated that the calc alkaline char- 
acter of the magmas of the volcanoes decreases 
regularly from the foredeep to the hinterland. 
It is interesting that a similar zonal arrangement 
of volcanoes is shown in the Japanese islands 
and their environs. 

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GEOLOGY AND GEOPHYSICS 

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VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Table I. 

Numbers of the available chemical 
analyses from each volcano and zone 
with their sources or analysts. 

I Volcanoes on the Kurile Arc 
la, Tisima (Chishima) volcanic zone; 16 



lie, South part of Nasu volcanic zone; 33 
Nyoho-Akanagi 

8: M. Yamasaki (1954) 
R. Ota (1953) 



Akagi 5 : 

Kusatu-sirane 

5: 
Asama 1 5 : 



Praramusiru 

Harimkotan 

Urup 

Etorohu 

Kunasiri 

Siretoko-Io- 

zan 
Masyu 
Me-akan 



J. Suzuki&Y.Sasa(1932) 
1:T. Nemoto(1934) 
4:T. Nemotb(1935) 
1 : Y. Katsui (unpublished) 
1 : S. Kozu (1909) 



1: S. Kozu (1909) 

5: Y. Katsui (1955) 

1 : Y. Katsui (unpublished) 



Ib, Western subzone of Tisima volcanic zone 
(Daisetu volcanic zone) ; 9 
Daisetu 5: Y. Katsui (unpublished) 

Takanegahara 1 : Y. Katsui (unpublished) 
Tokati 2: F. Taba & H. Tsuya 

(1927) 

Furanodake 1 : Y. Katsui&T. Takahashi 
(unpublished) 

Ic, Inner subzone of Tisima volcanic zone; 3 
Alaid 1 : J. Suzuki & Y. Sasa 

(1932) 
Taketomi 2: H. Kuno (1935) 

II Volcanoes on the Northern Honsyu Arc 

Ila, Northern subzone of Nasu volcanic zone; 
10 

Risiri 9: Y. Katsui (1953) 

Syokan 1 : Y. Katsui (unpublished) 

lib, Nasu volcanic zone; 68 

Yotei (Ezo-huzi) 4: Y. Katsui (1956) 
Tarumai 18: T. Ishikawa (1952) 
Usu 5: K. Yagi(1953) 

Komaga-take 

14: S. Kozu (1 909), H. Tsuya 

(1930), 

K. Seto&T. Yagi(1931) 

and K. Seto (1931) 
Hakkoda 1 : Y. Kawano (1939) 
Towada 6: Y. Kawano (1939) 
Iwate 2: S. Yamane (1915) 

Kurikoma 1 : Y. Katsui (unpublished) 
Onikobe 1 : Y. Katsui (1955) 
Naruko 6: Y. Shiga (1929) 
Zao-san 2: S. Nishiyama (1887) and 

T. Kochide 1889 

Azuma-san 2: S. Nishiyama (1887) 
Adatara 1 : S. Nishiyama (1887) 
Bandai 5: S. Nishiyama (1887) 



H. Tsuya (1934a) 
S. Kozu (1932), H. Tsuya 
(1933), K. Kani (1935) 
and I. Iwasaki (1936) 
lid, Tyokai (Chokai) volcanic zone; 16 

Iwaonupuri 2: O. Hirokawa & M. 
Murayama (1955) and 
S. Kozu (1909) 

Osima-osima 4: Y. Katsui (1954) 
Oshima-Kozima 

: Y. Katsui (unpublished) 
Iwaki-san : Y. Katsui (1954) 
Kanpu : Y. Katsui (1954) 

Ichinomegata : H. Havashi (1955) 
Tyokai-san : Y. Katsui (1954) 
Sumon : F. Honma (1922) 

III Volcanoes within Fossa Magna region and on 

the Izu, Bonin and Id-zima Island 
Ilia, Northern subzone of Huzi (Fuji) volcanic 
zone; 82 

Kurohime 3 : H. Tsuya (1937) 
lizuna 3 : H. Tsuya (1937) 

Kayaga-take 2:M. Ichiki (1929) 
Kurohuzi 1:H. Tsuya (1937) 
Huzi (Fuji) 

&Asitaka 14 : H. Tsuya (1934 & 1937) 
Amagi & 
Omuro-yama 51 :D. Sato (1925), H. Tsuya 

(1937), (1954), H. Kuno 

(1954) and H. Kurasawa 

(1956) 
Nii-zima 3 : H. Tsuya (1929), K. Kani 

(1935) and S. Nagai 

(1936) 
Kozu-sima 5 : H. Tsuya (1929) 

Illb, Southern subzone of Huzi volcanic zone; 
66 
Hakone 8: R. Inoue (1913) and H. 

Kuno (1950) 

Taga 12: H. Kuno (1950) 

Usami 8 : H. Tsuya (1937) 

6-sima 12 : S. Tsuboi (1920), S. Kozu 
(1927), K. Kani (1934), 
H. Kuno (1950) and 
R. Morimoto et al (1953) 
To-sima 1:S. Kozu (1927) 
Utone-zima 1:S. Kozu (1927) 
Miyake-zima 6: H. Tsuya (1929 & 1937) 

and S. Kozu (1928) 
Mikura-zima 1 : H. Tsuya (1937) 

233 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Hatizyo-zima 1 
Aoga-sima 4 

Myozin-syo 6 



Tori-sima 
Ogasawara 
(Bonin) 



1 



H.Tsuya(1937) 

H. Tsuya (1937) and 

N. Isshiki(1955) 

H. Tsuya et al (1953), 

H. Hamaguchi and M. 

Tasumoto (1953) and 

R. Morimoto (1954) 

H. Tsuya (1937) 



IIIc. 



Y. Kikuchi (1890), W.H. 
Hobbs & W.F. Hunt 
(1926), K.Tsuboya (1932) 
and H. Tsuya (1937) 

I6-zima volcanic zone; 14 

I6-zima Islands 



14: H. Tsuya (1936) 
I. Iwasaki (1937) 

IV Volcanoes of South-Western Japan 
IVa. Norikura volcanic zone; 8 



and 



16-dake 

Yakeyama 

Norikura 



Ontake 



1:T. Kato (1913) 
2:D. Sato (1925) 
4: S. Kozu (1911), 
Washington (1917) 
D. Sato (1925) 
l:J.P.Iddings(1913) 



H.S. 

and 



IVb. Daisen volcanic zone; 31 



Sambe 



4: S. Kozu & B. Yoshiki 



(1929) 

KuzyQ 1: D. Sato (1925) 

One-zima 1 : E. Sakai (1939) 
Hutago 13 :K. Komada (1916) and 

Y. Kawano (1937) 
Unzen 1 1 : Vole. Soc. Japan (1936), 

K. Kani(1935)T.Ogawa 

(1924) and D.Sato (1925) 
IVc, Northern part of Ryukyu volcanic zone: 

32 
Aso 16: F. Honma & M. Mukae 

(1938), K. Yamaguchi 

(1938) and I. Sugano & 

G. Arimura (1957) 
Kirisima 16: D. Sato (1925) and 

K. Takahashi & K. Sawa- 

mura (1957) 
IVd, Southern part of RyukyQ volcanic zone; 

33 

Sakurazima 16: Vole. Soc. Japan (1936) 
J6-zima 2: H. Tanakabate (1935) 
Kuchinoerabu 

2:F. Honma (1944) 
Suwanose-zima 

13 :S. Murauchi (1954) and 



H. Matsumoto (1956) 



Table II. 

Numbers of the lavas plotted above and on the 
line showing the average of volcanic rocks in Japan 
respectively in figures 2 and 3. 



Zone 


Total 
numbers 


gz \ 
above 


'alue (al-alk, 
on above 


) value 
on 


la 
Ib 
Ic 


16 
9 

3 


14 






2 


1 

5 
4 


8 
3 



6 
5 
6 


13 

1 
1 


1 





4 
2 


" 5 

2 

2 


3 
1 

5 


Ha 
lib 
lie 
lid 


10 
68 
33 
16 



55 
19 
1 


1 
50 
16 

3 


Ilia 
Illb 
IIIc 

IVa 
IVb 
IVc 
IVd 


82 
66 
14 

~ 8 
31 

32 , 
33 i 


24 
58 


1 

5 

2 
18 , 


28 
33 

2 
10 
13 
8 



Table III. 

Number of the lavas below and on the lines 
showing the average values of volcanic rocks in 
Japan (Average J) and in circum Japan Sea region 
(Average JS) in c-(al-alk) values in figure 4, 
counted in every zones. 



Zones 

la 
Ib 
Ic 


Total 
numbers 


Average JS 


Average J 


below 


on 


below 


or 


16 14 

9 j 6 

3 I 3 


1 




5 
3 
1 





Ila 
lib 
He 
lid 


10 
68 
33 
16 


4 
59 

23 
8 


1 

! 

1 
1 




44 
11 
5 




2 
2 



Ilia 
Illb 
IIIc 


82 
66 
14 


64 
56 

4 


1 
1 


25 
28 
1 
f 

9 

12 

7 


7 
1 


1 
2 
2 



IVa 
IVb 
IVc 
IVd 


8 2 
31 i 13 
32 1 27 
33 11 




3 
3 




234 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Table IV. 



Numbers of the lavas below and on the lines 
showing the averages of volcanic rocks in Japan 
(Average J.) and in circum Japan Sea region 
(Average J.S.) in k-mg relation in figure 5, 
counted in every zone. 



Zones 


Total 
numbers 


Average J. 
below ! on . j 


Average 
below 


J.S. 

on 









i i 


i 




la 


T6 




i ~2~ 


16 





Ib 


9 





1 , 


9 





Ic 3 


2 


j 


3 ! 





lla 


10 


4 


' 


10 





lib 


68 


61 


1 


67 


1 


He 


33 


12 





24 


1 


lid 


16 


3 


I 


7 


1 


Ilia 


- - g2 ~ 


39 


3~ l 


75 


1 


Illb 


66 


60 


2 


66 





Illc 


14 


12 


, 


13 





_ - . | _ 


, 


i 


__. ; _ 




IVa I 8 


3 





5 ' 





IVb 31 


6 


1 


22 





IVc 


32 


5 


1 


15 





IVd 33 


10 


2 


31 






235 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



RELATIONS BETWEEN THERMAL SPRINGS AND STRUCTURE 

IN VIET-NAM 

H. FONTAINE 

Universite Nationale du Viet-Nam, Faculte des Sciences, Saigon, Viet-Nam. 

(Abstract) 

The 85 thermal-mineral springs of Viet-Nam Though they almost never emerge in the basalts 

are for the largest part related to large faults of the same geological period, they are neverthe- 

formed during block-movements at the end of less related to these and are situated on the 

the Tertiary and during the Quaternary. same lines of weakness. 



236 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



THE KAMCHATKA VALLEY OF TEN THOUSAND SMOKES 

G. S. GORSHKOV 

Laboratory of Volcanology, Academy of Sciences of the USSR, USSR. 



For the first time in history an eruption of the 
Bezymianny Volcano of the Klyuchevskaya 
group of volcanoes on Kamchatka- took place in 
1955-1956. The most important event of the 
eruption was a giant explosion on March 30, 
1956, which occurred at 5.11 p.m. local time 
(0.6. 1 1 a.m. G.M.T.). In a few minutes a colossal 
fan-shaped cloud of ashes had risen above the 
volcano. The lower border of the newly-formed 
giant "fan" was at 6-8 km, and the upper one at 
about 36 km. An extremely intense ash-fall 
stretched NNE from the volcano. Thus in the 
Klyuchi settlement (45 km distant from the 
volcano) the ashes fell for 3.5 hours and reached 
20 mm in thickness or 24.5 kg/m 2 in weight (the 
total from the beginning of the eruption being 
45 mm or 40 kg/m 2 ). Impenetrable darkness 
reigned in the area of the ash-fall; people were 
walking in the streets in search of their homes. 
Deafening rumblings of a thunderstorm followed 
one another. The air was charged with electri- 
city, telephones rang spontaneously, broadcasting 
loud-speakers fused, lead-ins of antennas sparkled. 
Ashes blown into the stratosphere by the explo- 
sion were caught by currents and passed over the 
North Pole, they were observed in England 3 or 
4 days later. 

It is interesting to note that the explosion on 
March 30 was not heard either near or at a 
distance. Nevertheless all the meteorological 
stations in the radius of over 1 ,000 km. registered 
the blast wave on barogramms. Thus, in Klyuchi 
(45 km. distant from the volcano) pressure changed 
to 23.5 millibar while in Markovo on Chukot- 
ka Js. (1,100 km. from the Bezymianny), to 1 
millibar. 

Sensitive microbarographs recorded the explo- 
sion wave everywhere which ran one and a half 
time round the Globe. 

As a result of the explosion the Bezymianny 
Volcano changed beyond recognition: from a 
slightly truncated cone it was transformed into a 
semi-circular caldera-volcano. The newly formed, 
immense crater embraced not only the summit 
but also the whole south-eastern slope to the 
foot, stretching 1.5 x 2 km. The top of the 
volcano became 150-180 m, lower its absolute 



height being reduced to about 2900 m, instead of 
the former 3085 m. 

The Sukhaya (Dry) Khapitsa Valley situated 
on the eastern slope of the volcano was found to 
be buried over a distance of 18 km. by an agglom- 
eratic flow of a chaotic mixture of ash, sand and 
Java blocks of all possible sizes. Thousands of 
secondary fumaroles were rising from the surface 
of this flow. 

The eastern surroundings of the volcano were 
covered with a layer of volcanic sand up to 0.5 
m in thickness till a distance of 10-13 km. Fur- 
ther East, at a distance of 27-29 km, the thick- 
ness of the sand rapidly decreased to a few cm 
only. During the explosion ashes were blown 
out of the crater with a colossal energy, like a 
stream out of a giant sand ejecting apparatus. 
The strength of the explosion broke and cut big 
trees with diameters up to 25-30 cm. at a distance 
of 25 km. 

The ash which fall on the ground still contained 
a certain amount of gases and was very mobile 
("flowing"). It moved down the hills and steep 
slopes filling all the river valleys in the neigh- 
bourhood of the volcano with sandflows several 
meters thick. 

At the moment of the explosion the ash was so 
hot that it burned the bark of trees and bushes 
at distances of 27-29 km from the erupsion centre, 
while some trunks were burned completely. Rapid 
melting of snow took place, under the cover of 
hot ashes, over an area of about 500 km 2 . 

In the Sukhaya Khapitsa and on the slopes of 
the Zimina and Klyuchevskaya Volcanoes mud 
flows (lahars) developed which rushed down, 
transporting big stones and destroying everything 
on its way. 

The mud flows ran eastward to the B. Khapitsa 
River turned north following the valley and 
discharged themselves into the valley of the 
Kamchatka River. Two large lakes were found 
burned under mud flow deposits. 

The most interesting consequence of the explo- 
sion on March 30 was the formation of a large 
agglomerate flow with thousands of secondary 
fumaroles in the Valley of the Sukhaya Khaiiitsa 
River. This picture so much resembled the 

237 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Sketchmap of the area influenced by the explosion of Bezymianny on March 30, 1956, 1 . boundary of the area ruined 
by the explosion, 2. agglomerate flow, 3. mud deposits, 4. routes of mud flows (lahars), 5. expedition camps. (Compiled 
by the author). 



description of the famous Katmai flow in Alaska 
that the Sukhaya Khapitsa valley was given 
the name: "Kamchatka Valley of Ten Thousand 
Smokes". 

The agglomerate flow has been investigated 
three weeks after the explosion and more tho- 
roughly in the summer of 1956. The contours of 
the flow were found to be rather complex (see 
sketchmap) 

In many parts of the agglomerate flow explosive 
craterlets were scattered. The explosions occur- 
red after the flow stopped and judging from all 
data were caused by the ejection of incandescent 
masses on thick concentrations of ice or snow. 

At the moment of the eruption the agglomerate 
saturated with gases had a strong fluidity and 
could not stay on steep slopes of the volcano. 
Due to this, agglomerates practically lack on the 
volcanic slopes and the agglomerate flow starts, if 

238 



not from the crater, from the foot of the volcano 
where the angle of the slope does not exceed 4 
or 5. 

The length of the agglomerate flow is 18 km, 
-its max. width is 4 km. The area covered by the 
flow is 55-60 km 2 . The thickness of the flow 
in the marginal part amounts to 20-30 m, in the 
central part it is, doubtless, higher and probably, 
reaches 70-80 m. If we accept an average thick- 
ness of 50m, the volume of the agglomerate flow 
is about 3 km 3 . 

The overwhelming majority of the fumaroles are 
found on the walls and beds of constant and 
temporary water ways. The temperature of the 
fumarole gases sometimes rises to 200 but is in 
the main about 100. According to composition 
the fumaroles represent steam flows with ad- 
mixtures of air and acid gases (CO 2 , H 2 S, SO 2 ). 
The air lacks oxygen: the ratio of oxygen to 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



nitrogen is 1 :48 instead of 1 :4 in the atmosphere. 
It is evident that in the thickness of the 
agglomerate flow vigorous oxidizing processes 
take place. 

On clear and hot days when mountain glaciers 
melt more vigorously and water rapidly arrives at 
the bed of the Sukhaya Khapitsa the banks 
composed of hot agglomerates soon wash away 
and fall into the water. Every crumbling of 
caused a steam eruption, a kind of a "secondary 
eruption", with ash clouds rising to 200-300 m. 
Especially strong explosions took place on 
days when rain fell in the mountains. 

Then, hundreds, even thousands of secondary 
eruptions occurred at the surface of this agglom- 
erate flow. 

Ash clouds rose to 0.5 km. and drifted off 2 or 
3 km., dispersing ashes. 

The waters of the Sukhaya Khapitsa were 
overfilled with loose materials forming a dense 
but rather mobile mud in which large rocks were 
easily transported. Enormous quantities of hot 
material crumbled down into the water and 



caused a noticeable rise of temperature in these 
cold glacial waters (up to 35-45 in the Sukhaya 
Khapitsa). Throughout the winter of 1956/1957 
the agglomerate flow remained warm and was 
not covered with snow. Fumarolic activity on 
the flow was still observed in 1957. 

The strength of the 1956 eruption of the Bezy- 
mianny Volcano can be compared with that of 
the eruptions of Krakatao in 1883, Katmai in 
1912 and Pelee in 1902. The nature of the eruption 
resembles that of Mt. Katmai. 

The first preliminary results of a comparative 
study of the eruption of the Bezymianny volcano 
with that of the Katmai Volcano in Alaska, ena- 
bles, us to reveal some erroneous conceptions on 
the eruptive conditions of the Katmai and the 
origin of the Valley of Ten Thousand Smokes. 

We think the source of tuffs in the Katmai 
valley not to be fissures under the valley, but 
central craters of the Katmai and Novarupta, 
besides it is very doubtful to speak of an assimilat- 
ion of moraine material by rhyolite magma in 
the by-surface conditions. 



239 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



A REPORT ON THE PUNA RIFT ERUPTION OF KILAUEA VOLCANO, 

FEBRUARY 28 -MAY 26, 1955 

GEORGE C. RUHLE 

Hawaii National Park, National Park Service , U.S. Department of Interior, Hawaii. 



(As an eye-witness throughout the eruption, 
the reporter has relied heavily on the assistance 
of Drs. Gordon A. Macdonald and Jerry P. 
Eaton of the U.S. Geological Survey. Ref. The 
Volcano Letters 529530; July-December, 1955.) 

The volcano Kilauea (4,090 feet), which does not 
need introductory description to geologists any- 
where, rests against the southern flanks of the 
greater shield volcano, Mauna Loa (13,680 feet) 
on the island of Hawaii. At the present time, 
its principal vent, Halemaumau, is located within 
a summit caldera, 2,800 acres in area. Hale- 
maumau marks the junction of the two major and 
one minor rift zones that radiate outward and 
have been the scenes of ten eruptions recorded 
since 1823 when visit and observation of the 
volcano was first recorded in print. Of the three 
rifts, the Puna extends southeasterly from 
Halemaumau, curves easterly, and with a trend 
of NO/65/E disappears beneath the sea at Cape 
Kumukahi, the easternmost point of the island 
as well as of the triangularly shaped Puna District 
which has been built from flows from the rift. 
Some 70 vents, a dozen pit craters, and long, 
deep fissures extend throughout the surface 
trace. An eruption of Heiheiahulu Crater is 
dated 1750, just before the discovery of the 
Hawaiian Islands by Captain Cook in 1778. 
Subsequent activity along the rift has occurred 
in 1790 (?), 1840, 1922, and 1923. The rift was 
site for swarms of earthquakes in 1924 whose 
epicenters extended outward from twelve miles 
east of the summit caldera. These preceded the 
celebrated 1924 steam-blast eruption of Hale- 
maumau. Two strong earthquakes with foci 
twelve miles deep were registered south of Pahoa 
on March 30, 1954. These and the spectacular 
though short-lived summit activity on May 31, 
1954 might be considered premonitory and pre- 
lude to the 1955 eruption. 

The 1955 acivity was the first flank eruption of 
Kilauea since 1923 and the first in East Puna 
since 1840, the interval of quiet being 115 years. 
It had aspects of three separate eruptions, each 
of which being accompanied by premonitory 
seismic disturbance. Activity shifted irregularly 
over twenty miles of the rift, in part progressing 
240 



up the slope of the volcano. Scientists observed 
and photographed at close range the entire 
sequence of activity from the initial opening of 
cracks and fissures, the first appearance of fume, 
then lava, the progressive development of foun- 
tains, vents, cones, and flows, to the final cessa- 
tion of activity. The actual formation of a pit 
crater was also observed. 

The 1955 eruption occurred in what for the 
island of Hawaii is a relatively heavily populated 
and cultivated area. It is a region of limited 
access and mobility by road, which presented 
problems of evacuation and relief that were 
aggravated by clamor of tourists and locals wishing 
to see the spectacle at close range. Because of 
the threats of danger it was necessary to evacuate 
numbers of people with all of their moveable 
possessions. Attempts, in part successful, were 
made to throw up barriers to divert the course 
of advancing lava streams. 

In the latter part of 1954 and in early 1955 
hundreds of earthquakes with foci in the Puna 
area grew in number and intensity. Activity 
broke out on the east rift twenty miles below 
Halemaumau within a few minutes of 8 a.m. on 
February 28. First cracks opened in the ground. 
Soon milky-white fume, mostly water vapor 
and sulfur oxides, appeared in increasing volume 
to be followed by the first lava either as red hot 
lapilli or as a viscous swelling bulb. 

A chronological, detailed discussion accompa- 
jiies presentation of the film. It starts with 
"scenes of cultivated and forested land and Kapoho 
village, later threatened by flows. The first 
activity scenes, taken later in the morning 
from an airplane, shows fume pouring densely 
from long fissures arranged en echelon. The 
first extrusions of viscous lava are shown which 
move slowly into adjacent caneland. A small 
cone of welded spatter is built up. Close views 
taken at night looking directly into the vents show 
seething activity and the rapidity with which the 
incandescent blobs of lava are tossed out to 
darken as they are plastered on the lip and sides of 
the cone. A typical flow of the opening days is 
shown and a lava fall of hot liquid plunges into 
an earthquake crack fifty feet deep. The phreatic 



explosions at noon of March 1 ended this early 
phase. All external evidence of extrusion ceased, 
but great seismic disturbance continued and 
wide cracks were torn open in the ground. Ex- 
trusive activity was renewed on the afternoon of 
March 2 with rows of fountains playing 100 to 
150 feet high. Flows from these endangered 
Kapoho. By March 4, one fountain with a 
temperature of 1100-1 120 C. as measured with 
optical pyrometer, grew to a height of 800 feet and 
played hour after hour through the long night. 

The intense activity of March 13 is shown at 
length with the opening of the fissures, first in 
cleared land, then across the Kalapana Road from 
which wisps of dark brown volatilized asphalt 
show against the milky background. The first 
blob of lava appears that grows into a cone thirty 
feet high by noon of next day. Scenes of the Ha- 
yashi homestead nearby are shown which, though 
not covered by lava flow, later caught fire from the 
intense heat and burned to the ground. Nearby 
trees are plastered with lava. A day later an- 
other great fountain appeared a mile downslope 
which afforded artistic views through the sparse 
branches of trees. A turbulent flow develops 
from this fountain. Great blocks of incandes- 
cent lava, some of them weighing twenty or more 
tons, are rafted with case down the molten 
stream. Heat waves dance above the rapidly 
flowing stream. This was the first flow eventually 
to reach the ocean. 

Close views are taken from the top of a cone 
which show the great force with which the stream 
of lava is ejected and the manner in which spatter 
cones are built. The vents are shown during 
an interval of quiet, blue flames of burning sulfur 
playing above them. When fountain! ng is re- 
sumed, a succession of scenes shows the spatter 
developing into a flow which grows to a mighty 
flood moving across the Kalapana Road next 



VOLUME 12_ _ GEOLOGY AND^ GEOPHYSICS 

day. A deep channel is melted by the mobile, 
hotter lava as it moves down earh'er expansive 
flow already chilled. The camera is pointed into 
the channel to register the surface of the stream 
in detail. The forward front of the flows have 
cooled to a slow advance of a wall about ten 
feet high. Chunks of solid matter on the surface 
tumble over the face with a melodious tinkling 
sound. Burning gases, derived from organic 
matter picked up along the course, play along the 
edge and top. Aa lava is characterized by a 
rough, clinkery surface. The aa flow pushes 
slowly, irresistably ahead pushing over pandanus 
and coconut trees in its path. Air views are 
shown of braided pahoehoe streams rushing over 
chilled, blackened earlier flows. The source 
fountains are shown as a new stream develops 
and moves rapidly into an ohia forest, the burn- 
ing trees appearing as scintillations on the 
orange-yellow stream. 

At last the streams reach the sea from which 
a column of steam ascends thousands of feet into 
the air. Occasional littoral explosions occur as 
the lava plunges over the thirty foot wave-cut 
cliff into the cold water. These appear as black 
jets of finely divided, black, glassy material which 
is reworked by wave action to form black sand 
beaches for which Hawaii is famous. These are 
luminous at night, as can be seen on the screen. 

The intense fountaining and mighty pahoehoe 
rivers of May 25 and 26 are especially interesting. 
Fountaining and extrusion of lava came to an 
abrupt close at 11:15 a.m. on May 26. 

The film closes with scenes taken from a heli- 
copter to show cones, sulfur-yellow and white 
incrusted vents, the great new pit crater, the 
widespread destruction and desolation. It ends 
with a rapid recapitulation of a half dozen 
highlights of the eruption as a summary. 



241 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



VOLCANISM IN NORTHERN AND CENTRAL SUMATRA 

GEORGE A. DE NEVE 

Department of Geology, Andalas University, Bukittinggi, Central Sumatra. 

(Abstract) 



Geological and volcanological investigations 
were carried out in 1 952- 1 953 in the eastern part of 
Northern Sumatra (Lake Toba and immediate 
surroundings) and in Central Sumatra (Lake 
Manindjau, Lake Singkarak, the surroundings of 
Muara Labuh and Lake Korintji). 

The longitudinal fault-troughs extending from 
the area south of lake Toba to the volcano Talang 
in Central Sumatra with the two lakes Danau di 
Atas and Danau di Bawah were studied in detail. 
During the early Quaternary and also more recent- 
ly this area was the scene of violent eruptions of 



acid pumice tuffs. The existence of long lines of 
fumaroles and mofettes and occurrence of many 
earthquakes along the Tarutung-Angkola-Gadis 
rift valley, and further to the south show that the 
bordering faults are still active. 

Of volcanism in the areas of Northern and 
Central Sumatra could be said that really active 
volcanoes seem to be concentrated in the last 
mentioned region. With the exception of the 
Marapi volcano in the neighbourhood of Bukit- 
tinggi no other Sumatran volcanoes have poured 
out lava in recent historical time. 



242 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



VOLCANISM ON THE ISLAND OF FLORES AND THE GEOLOGICAL 
HISTORY OF THE COLOURED LAKES OF THE KELI MUTU VOLCANO 

GEORGE A. DE NEVE 

Department oj Geology, Andalas University, Bukittinggi, Central Sumatra. 

(Abstract) 



One of the Lesser Sunda Islands is Flores 
which has 17 active volcanoes on a relatively 
small area of 15.000 sq. kms. The western and 
central parts of the island of Flores consist of 
older (Tertiary) volcanic rocks and igneous 
intrusions. 

The young Quaternary volcanoes occur along 
the southcoast of West Flores. In the Central 
part of the island they are present not only along 
the southcoast but on the northern shore too 
(Paluweh volcano). On Eastern Flores the gean- 
ticline shows an axial plunge, older volcanic 
rock and granodioritic intrusions are not exposed, 
and only young volcanoes are found. 



Aerial reconnaissances above the volcanoes 
of the island of Flores were first made in 1953 by 
the Volcanological Survey of Indonesia, followed 
afterwards by volcanological and geological 
investigations carried out in detail by three 
different field-parties. 

An outline is given concerning the geological 
history of the Keli Mutu volcano in Central 
Flores. The three coloured lakes discussed are 
the showpieces of Flores and of Indonesia: blue- 
ish-green (Tiwu Atu Mbupu^Lake of the Aged 
People), troubled-green (Tiwu Nua Muri Kooh 
Fai = Lake of the Young Men and Virgins) and 
red (Tiwu Ata Polo = Lake of the Bewitched). 



243 



PROCEEDINGS OF THh NINTH PACIFIC SCIENCE CONGRESS 



GEOCHEMICAL EFFECT OF 
THE BEZYMIANNY VOLCANO ERUPTION 

G. S. GORSHKOV and I. I. TOVAROVA 

Laboratory of Volcanolog\\ Academy of Sciences of the USSR, USSR. 



During the eruption of the Bezymianny Volca- 
no an immense quantity of pyroclastic material 
was ejected. 

As a result of the rains and still more of the 
intensive melting of snow, great quantitives of 
water passed through the agglomerate flow and 
the ashes, carrying away considerable quantities 
of dissolved matter to the ocean. 

To determine the potential quantity of mineral 
matter carried away by the surface water into the 
Pacific an extraction of easily dissolved substances 
from fresh pyroclastic material was made. The 
extraction was carried out from a loose fraction 
with a diameter of less than 1 mm. The analysis 
was made from water drawings obtained by four- 
time extraction of samples in equal amounts of 
water, at room temperature, during 48 hours. 

These conditions of extraction resemble a 
miniature process of the washing of eruptive 
products by surface water and are able to give an 
idea about the quantity of matter carried away 
by the water. 

The water extracts were used to determine 
the contents of CI', SiO 2 , Fe, Ca", Mg", Na, K 
and SO" 4 . 

The results obtained are given in Table 1, 
where : 

I = water extract from ashes fallen in the 
neighbourhood of the volcano during the initial 
period of eruption. 



II = water extract from ashes fallen during the 
main explosion. 

III - water extract from the material of the 
agglomerate flow. 

(mean values from the analysis of five samples). 

Table 1. 
Samples Contents in mgr/100 g. of the material 





; cr 


1 SO/ 


SiO 2 


Fe 


iMg" 


Ca" 


JNa 




K 


I 


195^88 


J40O4 


2.95 


10.57 


21.5 


151 ~ 


,8.r 


3 


.11 


li 


155.04 


il98.4 


2.71 


8.83 


iJO.2 


81.2 


'5.15 


i 


.68 


HI 


122.7 


1165 


2.4 


5.6 


! 3.11 


54 


15.5 


1 


.7 



During the main explosion on March 30,1956 
about 0.5 km 3 of ashes was ejected and the same 
quantity during the initial period of the erup- 
tion. The volume of the agglomerate flow is 
about 3 km 3 . The specific weight of loose rock 
is assumed to be 1.8. Hence the weight of the 
eruption products is: 0.9. 10 9 tons for ashes of the 
first and the main phases and 5.5.10 9 tons for the 
agglomerate flow. 

Considering that the fine fraction of the agglom- 
erate flow is but about 80 per cent of the 
whole mass we obtain the following values of 
easily-dissolved components of pyroclastics : 



Table 2. 



Contents in to 




cr 


SO/ 


SiO 2 


Fe 


I 


8.6x105 


3.6x106 


2.7x10^ 


1.0x105 


11 


5.0x105 


1.8x106 


2.4x104 


0.8x105 


III 


10.0x105 


7.4x106 


10.0x104 


2.5x105 


Total 23.6x105 


12.8x106 


15.1x104 


4.3x105 



Mg" 


Ca' 


Na 


K 


1.9x105 


1.4x106 


7.2x104 


2,7x104 


0.9x105 


0.7x106 


4.5x104 


1.5x104 


1.4x105 


2.4x106 


29.5x104 


7.6x104 


4.2x105 


4.5x106 


41 xl04 


11.8x104 



Thus, the total quantity of dissolved material is found to be 21. 10 6 tons. 



244 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



GEOLOGICAL SKETCH OF EL SALVADOR, C.A. 

FRITZ DURR 

Scrvicio Geologico National de El Salvador, El Salvador, C.A. 

(Abstract) 



Reconnaissance geology of the Republic of 
El Salvador, C.A. is presented. 95% of the 
territory is covered by volcanic rocks. They 
distinguish the following topographic units: coast- 
al plain, coastal mountains, young volcanic 
chain, interior mountains, interior valley and 
northern mountains. The coastal plain is covered 
by alluvial sediments. The volcanic coastal 
mountains as well as the interior mountains are 
considered to be of Pliocene age. The young 
volcanic chain belongs to the Pleistocene and 
volcanism is still active. The interior valley 
partly is covered by alluvial sediments, its base- 
mentrock consists of tertiary volcanic rocks. 
The northern mountains are build up by tertiary 



volcanic rocks, in their western part exist creta- 
ceous sedimentary rocks as well as granitic 
intrusions of probably miocene age. 

There are three prevailing tectonic trends: 
NNW, NNE and WNW. The last mentioned 
tectonic element partly forms two parallel graben, 
occupied by the young volcanic chain and the 
interior valley. 

Mineral deposits are connected with the men- 
tioned granitic intrusions (Fe, Cu, Pb, Zn, 
Mo) as well as with probably younger protru- 
sions (Au, Ag). None of these deposits is consid- 
ered to be of great value. Along the coast 
there are placer deposits of magnetite and 
ilmenite. 



245 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Symposium: Stratigraphic Correlation for the Pacific Area 

Convener: Teiichi Kobayashi (Japan) 

CIRCUM- OR TRANS-PACIFIC CORRELATION 
OF PALAEOZOIC CORAL FAUNAS 

DOROTHY HILL 

University of Queensland, Australia. 



Taking the Ordovician faunas first. When 
these were reviewed recently (Hill, 1951) nothing 
was known of the Pacific faunas. But Hill 
(1955) has since described a fauna from Tasmania 
and referred to another from New South Wales, 
and Duncan (1956) has discussed those of the 
western U.S.A.; these latter are largely unde- 
scribed, but Duncan indicates that a 'Chazy' 
faunule is present, comparable with that of the 
Appalachian province, and that the late Ordovi- 
cian fauna is related to that of western Canada 
(Wilson, 1926) and the Arctic. No E. Asiatic 
Ordovician coral faunas are known. The S.E. 
Australian fauna includes one that is either of or 
below the Zone of Nemagraptus gracilis; two of 
its five genera are unknown so early elsewhere 
in the world, and had the graptolites not been 
found, 1 would have thought the coral fauna 
Trenton at earliest. It appears then, that we 
know at present too little of the ranges of the 
earliest coral genera to use them safely in correla- 
tion by stages from continent to continent: for 
the Ordovician close circum- or trans-Pacific 
correlation of coral faunas is not yet possible, due 
mainly to paucity of knowledge. 

Silurian corals are known in more Pacific 
countries. Only in eastern Australia are Valen- 
tian corals reported, and these are not yet de- 
scribed. Horizons for the Wenlock and Ludlow 
Pacific faunas have been determined by refer- 
rence to the standard N. European sequences, 
where the middle and upper Silurian and Gedin- 
nian faunas form a well-marked unit that reaches 
its acme at the top of the Wenlockian and then 
declines. In E. Australia a fauna less rich than 
the European has been correlated with the top 
of the Wenlockian and possibly the base of the 
Ludlovian (Hill, 1940). In Japan (Sugiyama, 
1940) a fauna more similar to the Australian than 
to the European indicates approximately the same 
horizon, and in China (Lindstrom, 1883; Grabau, 
1925, 1930; Wang, 1947) and Korea (Ozaki, 
1934) a similar fauna appears more European 

246 



than Australian. On the eastern Pacific margin, 
the Silurian coral faunas are ill-described. 
Duncan (1956) compares those of the U.S.A. 
with the Niagaran faunules of eastern N. America 
which are indeed quite similar to those of Europe. 
Hume (1954) and Laudon and Chronic (1949) 
list names of genera for West Canada, and 
compare them with Niagaran faunas. 

Thus present knowledge of American Silurian 
forms is too slight for trans- or circum-Pacific 
correlation, but on the western side of the Ocean, 
the Japanese and N.S. Wales faunas are more 
similar to each other than either is to the Euro- 
pean faunas from which their equivalent horizon 
was deduced. 

Devonian Pacific corals are better known and 
the faunal sequences have been reviewed recently 
(Hill, 1957). Gedinnian Pacific faunas are 
known only in E. Australia. Emsian faunas 
occur in Indochina (Fontaine, 1954) and in E. 
Australia, Couvinian in Burma (Reed, 1908), 
Indochina (Fontaine, 1954), China (Wang, 1948), 
E. Australia and New Zealand (Hill, 1956). The 
New Zealand and East Australian faunas have in 
common at least one genus not known in Europe 
or Asia. Givetian faunas occur in Yunnan 
-(Fontaine, 1954) China (Yoh, 1937; Wang 1948) 
and E. Australia, remarkably similar to those of 
Europe and Asia, and for these there is no 
greater similarity of Chinese to Australian 
faunas than there is of either to European 
faunas. 

Indeed the Western Pacific Devonian coral 
faunas seem to form one zoogeographic unit with 
those of Europe. Frasnian faunas are not known 
in E. Australia, but occur in Burma (Reed, 1908), 
and China (Smith, 1945) where again they are 
remarkably like those of W. Europe. Smith 
however has shown that two phillipsastraeid 
species are very similar to and another is iden- 
tical with species of similar age from W. Canada. 
This is a remarkable instance, suggesting circum- 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



or trans-Pacific migration, and though the age of 
the deposits on each side of the Pacific was 
determined by reference to European sequences, 
it seems that further study of the Chinese faunas 
is desirable to show whether more species common 
to China and Canada can be found, and close 
trans-Pacific correlation established. 

In the Western Pacific all the European 
Devonian stages can be recognised by the genera 
present. There is in general however a difficulty 
in correlating to a smaller unit than the stage and 
correlation by identity of species is not yet 
possible. There are variations in the relative 
abundance of genera apparently both with 
time and with place, and we cannot yet distinguish 
the time variation from the place variation; 
subgeneric differentiation may help in this 
problem; and the discovery of deposits in inter- 
vening regions may permit some correlations by 
assemblages of identical species over limited 
areas. 

In the eastern Pacific, the oldest known Devo- 
nian coral fauna is in the basal 500 ft. of the 
Nevada limestone. Many of its genera are 
endemic, but it has some links with the Atlantic 
Onandagan, regarded as Emsian or early Couvi- 
nian. It has little resemblance to that of the W. 
Pacific. In the Nevada limestone between 500 
and 1800 feet above the base, three species 
show remarkable resemblance to three Australian 
early Couvinian species, and HcUolites makes 
its first known Devonian appearance in N. Ameri- 
ca; this is possibly evidence of trans-Pacific 
migration; whether it can be used in trans-Pacific 
correlation is not yet clear, as there is still some 
controversy in America about the horizon of 
this section of the Nevada limestone in terms of 
both the European and east American standards. 

Givetian and Frasnian faunas are widespread 
in western N. America, and are of European and 
hence west Pacific type, rather than eastern 
American, Hill (1957) concluding that the W. 
Pacific and European and Australian regions 
then formed one zoogeographical province. 
Indentity of Canadian and Chinese Givetian 
species has been noted above. 

During Famennian times coral faunas probably 
occurred in Canada, but have not been clearly 
distinguished from Frasnian faunas. 

The Carboniferous coral fauna seems to have 
begun in Famennian times. In Tournaisian 
faunas, in the West Pacific, except perhaps in 
China (Yii, 1933) corals are too rare for use in 
stage correlation. In the eastern Pacific, a dis- 
tinctive fauna of colonial Rugosa is present 



(Hill, 1948), but its age is best established by the 
non-coral elements. In the Visean and Namu- 
rian, coral faunas in E. Australia, China and 
Japan may be correlated with the European 
stages largely on their colonial Rugose genera, 
the solitary Rugosa tending to be distinctive in 
each region; the resemblance between Australian 
and Sino- Japanese faunas is less striking than in 
the Silurian. East Pacific Vis6an and Nanutrian 
faunas are rather distinctive, even in their colo- 
nial Rugosa, but contain one genus (Lithostro- 
tionella) known elsewhere at the time only in 
China. This may indicate some degree of migra- 
tion and hence possibilities of direct circum- 
Pacific correlation. 

In the Bashkirian and Moscovian, reasonably 
rich Pacific coral faunas are known only in 
Southeast Asia, and are closely correctable with 
those of Russia. In N. America the equivalent 
early Pennsylvanian coral faunas are rather 
scanty. Post-Moscovian and pre-Sakmarian 
corals are not known in sufficient numbers in 
Pacific countries for reliable correlations. 

The east Asiatic Sakmarian coral fauna is 
quite rich in colonial corals and is directly corre- 
latable with east European Tethys (not with the 
Urals). In Indonesia and Australia however, 
only solitary, non-dissepimented corals are known, 
but are of universal, long-ranging genera, simi- 
lar to those of the eastern Pacific Wolfcampian, 
where however some colonial Rugosa in British 
Columbia and Texas do permit correlation with 
the Asiatic fauna. 

In the Artinskian, this Tethyan colonial fauna 
continues in cast Asia, but only solitary, long- 
ranging, universal genera (and some endemic 
genera) occur in Indonesia, E. Australia, New 
Zealand, and in the Eastern Pacific in the Leo- 
nardian of U.S.A., so that we have no good 
grounds here for trans- or ci re urn-Pacific correla- 
tion. 

In the Kungurian this Tethyan colonial fauna 
reaches the height of its development in China 
and Japan (in the Neoschwagerina-Verbeekina 
Zone with Leptodus = Lyttonid) but in Australia 
and on the eastern side of the Pacific (Ward) 
only small solitary Rugosa and long-ranging 
Tabulata are known, of no great value for 
trans-Pacific correlation. 

In the Kazanian, in Japan ( Yabeina Zone) and 
also in the Lepidolina Zone which however may be 
younger than Kazanian, the Tethyan 'colonial' 
fauna is still rich, and has spread to New Zealand, 
where representatives occur at the northern tip, 
so that a New Zealand - Japan correlation is 

247 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



possible. But in China, Indonesia and Australia 
only small solitary Rugosa (some endemic) occur, 
of no great value for correlation. On the eastern 
side of the Pacific in the Capitanian, a few colonial 
Rugosa permit correlation with Tethys and East 
Asia. 

In the highest Permian, corals are so rare in the 
Pacific region that they are at present of no value 
for correlation. 

REFERENCES 

The coral literature on which this review is 
based is too extensive for listing here, but may be 
found in the following compilations or review 
papers : 
Bassler, R.A., 1950, Faunal lists and descrip- 



tions of Palaeozoic Corals. Mem. 

GeoL Soc. Amer. 44. 
Duncan, H., 1956, Ordovician and Silurian Coral 

Faunas of Western United States. Bull. 

U.S. GeoL Surv. 1021-F. 
Hill, D., 1948, The distribution and sequence of 

Carboniferous Coral Faunas. GeoL 

Mag. 85: 121-148. 
, 1951, The Ordovician corals. Proc. 

roy. Soc. Qld. 62: 1-27. 
1955, Ordovician corals from Ida 

Bay, Queenstown and Zechan, Tasma- 
nia. Pap. Proc. rov. Soc. Tas. 89:237- 

254. 
-_, 1957, The sequence and distribution 

of upper Palaeozoic coral faunas. Aust. 

J. ScL 19, (3a, ANZAAS): 42-61. 



248 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

CORRELATION OF FUSULINID ROCKS FROM" SOUTHERN 

SUMATRA, BANGKA AND BORNEO, WITH SIMILAR ROCKS FROM 

MALAYA, THAILAND AND BURMA 

GEORGE A. DE NEVE 

Department of Geology, Andalas University, Bukittinggi, Central Sumatra. 

(Abstract) 



Four occurrences of Upper Palaeozoic rocks 
containing fusulinids are described. 

The first record of Upper Palaeozoic from 
Borneo comes from J.G.H. IJbaghs who disco- 
vered pebbles with Fusulina spp., determined by 
Tan Sin Hok in a Lower Tertiary conglomerate in 
Kutai, East Borneo (1930). 

The Permo-Carboniferous Fusulinidae in limes- 
tones, marbles, jasperoids and combustible clay 
shales silicified into cherts from various loca- 
lities in West Borneo were found by F. Krekeler 
(1932, 1933). 

Two localities of limestone, containing Neo- 
schwagerina and Fusulina spp. in the Palembang 
area, South Sumatra (East of Bukit Pendopo) 
were discovered by K.F.G. Keil. Probably these 
limestones could be considered as continuations 



of the Tebo-Tabir facies of A. Tobler occurring 
in the Djambi area. Little is known concerning 
their geology, it may be probable that they are 
relics of overthrust sheets. 

About 18 kms. west of Palembang, in the 
Sekaju area pebbles with Radiolaria, Crinoidea 
and Fusulinids were found in a conglomerate of 
Old Neogene age by J. Van Tuyn (1931). 

From the island of Banka fusulinid foramini- 
fera were determined by the author in cavernous 
silicified limestones and fine crystalline quarlzites 
of the Sungailiat area near Aerduren collected by 
W.P. de Roever. 

Straligraphic correlation is discussed of the 
above fusulinids containing rocks with those of 
the Perlis area in Malaya, the Ban Ta-kli area in 
Thailand and the Shan States and Tcnasserim 
Yomas in Burma. 



249 



PROCEEDINGS OF THb NINTH PACIFIC SCIENCE CONGRESS 

FUSULINID ZONES OF EAST ASIA 

RYUZO TORIYAMA 

Kyushu University, Fukuoka, Japan. 



During the last decade, our knowledge concern- 
ing the Upper Paleozoic stratigraphy and paleon- 
tology have been much increased, and many new 
genera and species of fusulinids have been dis- 
covered and described in Japan. However, it is 
not much of an advancement in some regions in 
East Asia. 

It is generally accepted to divide the Middle- 
Upper Carboniferous (Pennsylvanian) and Per- 
mian rocks into nine fusulinid zones, namely, 
the Millerella, Profusulinella, Fusulinella, Pusulina* 
Triticites, Pseudoschwagerina, Parafusulina, NCOS- 
chwagerina-Verheekina, and Yabeina-Lepidolina 
zones in ascending order, all of which are now 
recognized in Japan. This paper briefly summa- 
rizes the recent advancements concerning the 
fusulinid zones of East Asia. 

7. Mlllcrella zone: In Japan the Millcrclla 
zone was first recognized in the Kitakami massif 
by Yabe (1 ) who confirmed that it is of 
Onimaruan age. Kanmera (2) described four 
species of Millerella with several species of 
Visean corals from the Kakisako formation of 
Kyushu, which was also correlated with the 
Onimaruan series of the Kitakami massif. Igo 
(3) recently reported the Millerella zone in the 
Ichinotani formation of the Hida massif, the 
lower subzone of which contains exclusively 
species of Millerella and is of Onimaruan 
age. In the Akiyoshi limestone the Millcrella 
zone has also been found recently, although its 
paleontological work has not been completed yet. 

Outside of Japan, the Onimaruan rocks are 
known to occur in North and South China and 
Indo-china, and probably in Thailand and 
Burma, but no species of Millerella of the Oni- 
maruan age has been reported nor described, 
except M. sp. from Minchen, Chilin of North 
Manchuria (4). 

2. Profusulinella zone: The Profusulinella 
zone is most poorly known in East Asia. In Japan 
it was first found in the Akiyoshi limestone with 
typical species of Profusulinella and two species 
of Akiyoshiella (5, 6). Igo (3) recently confirmed 
the existence of ihe Profusulinella zone in the Hida 
massif with undescribed species of Profusulinella 
and Paramillerella. It is in conformable relation 
to the underlying Millerella and overlying Fusu- 

250 



Imella zones. Except the above, Profusulinella 
zone has not been reported in any place in Japan. 
As I (5) already pointed out, however, it is highly 
possible thai the Moscovian rocks hitherto re- 
ferred to "Fusulinella bocki or F. biconica zone" 
may, if not always, comprise Profusulinella zone, 
and even Millerella zone in some case, in their 
lower part. In fact Onuki and Yamade (7) clarified 
that even the upper part of the Nagaiwa series 
of the Kitakami massif, which has long been 
regarded the standard of the Fusulinella zone 
in Japan, is not referrable to the Fusulinella zone 
but to the Profusulinella zone. 

In South China the lower part of the Huang- 
lung limestone (Ma. zone of Lee, Chen, and Chu) 
is seemingly referable to the Profusulinella zone, 
although it contains a mixed fauna of Profusuli- 
nella and Fusulinella. The stratigraphical range 
of the genus Profusulinella seems to be consider- 
ably wider in the Tethys region than in North 
America. 

3. Fusulinella zone: Rocks referred to the 
Fusulinella zone arc widely developed in East 
Asia. Most of them are characterized by F. bocki 
M oiler or F. biconica (Hayasaka) and their allied 
forms. Recent studies of Japanese geologists 
have shown that most, if not all, of the Fusulinella 
zone in the Moscovian formations is divisible 
into two parts, the lower part of which is charac- 
terized by rather primitive species of Fusulinella 
and the upper one by more advanced forms of 
Fusulinella and primitive forms of Fusulina. 

The Penchi series of North China and the 
upper part of the Huanglung limestone of South 
China are also characterized by nearly the same 
faunal assemblage as that in Japan. 

4. Fusulina zone : Paleontologically well-defined 
Fusulina zone is only known in Southwest Japan. 
Quite different from the typical fauna of the 
Moscovian Fusulinella zone, a characteristic 
fusulinid fauna was described by Kanmera (8) 
from the Yayamadake limestone of Kyushu, 
and recently reported by Igo (3) from the Hida 
massif of Central Japan. The fauna comprises 
certain advanced species of Fusulina and Wede- 
kindellina and most advanced forms of Fusulinella. 
Hidaella, an aberrant descendant of Fusulinella, 
also occurs in the Fusulina zone of the Hida 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 











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251 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



massif. It should be noted that the rocks of the 
Fusulina zone are unconformably overlain by the 
limestone of Triticites zone in Kyushu. 

5. Triticiies zone: The Carboniferous-Per- 
mian boundary problem has long been discussed 
in Japan, and Japanese geologists' efforts have 
born fruit of discovering the Uralian Triticites 
fauna in several places in Central and Southwest 
Japan in 1951 and later (10, 11, 72, 13). Kan- 
mera (12, 14) pointed out that the Triticites fauna 
of the Yayamadame limestone contains more 
primitive species than any form hitherto found 
in the lower Permian formations which associates 
with species of Pseudoschwagerina and Parasch- 
wagerina. 

At present our knowledge concerning the 
Carboniferous-Permian boundary will be summa- 
rized as follows: (1) A clear unconformity exists 
below the base of the Lower Permian Sakamo- 
tozawan formation, and the Uralian formation is 
missing Kitakami massif of Northeast Japan, 
Penchi and Huangchi series of North China, and 
Huanglung and Chuanshan limestones of South 
China. (2) No physical hiatus is recognizable in 
spite of the fact that the rocks of the Pseudoschwa- 
gerina zone directly overly those of Fusulinella 
or lower zones. Akiyoshi and Taishaku lime- 
stones in Japan, Koten and Jido series in Korea. 
(3) Although the Uralian Triticites zone is present, 
the Pseudoschwagerina and Triticites zones are 
still presumed to be an unconformable relation 
Yayamadake limestone in Kyushu. (4) Pseudo- 
schwagerina zone directly follows the Uralian 
Triticites zone without any physical break Omi 
limestone and Ichinotani formation in the Hida 
massif. 

6. Pseudoschwagerina zone : Among the Permian 
fusulinid zones, the Pseudoschwagerina zone is 
most widely developed in East Asia, and is flour- 
ished by extremely abundant species of schwager- 
inids including Pseudoschwagerina, Paraschwa- 
gerina, Pseudofusulina, Schwagerina, Dunbarinella, 
Triticites and smaller fusulinids. It must be 
remembered that the zone fossil, Pseudosch- 
wagerina, does not occur in the very basal part of 
the Sakamotozawan rocks, and that part of the 
Akiyoshi limestone, for example, is charac- 
terized by the predominance of species of Triti- 
cites (5). Careful comparative studies on the 
Lower Permian and Uralian Triticites faunas 
seem to be necessary. 

The similarity of the fauna of the Pseudoschwa- 
gerina zone found in Japan, North and South 
China, Indochina (15, 16) and Thailand (17) 
indicates that all these areas belonged to one 

252 



and the same faunal province in the Early 
Permian time. Minojapanella (18), Hayasakaina 
(19) and Toriyamaia (20 ) , recently described new 
genera in the Pseudoschwagerina zone, have not 
been found outside of Japan. 

7. Parafusulina zone: Not likewise in the Mid- 
continent region of North America, the Parafu- 
sulina zone of East Asia is sometimes hard to 
define paleontologically, and the stratigraphical 
range of the genus seemingly wider in East 
Asia than in North America, ranging up to the 
Yabeina-Lepidolina zone. So far as known, the 
best displays of the Parafusulina zone are seen in 
the Nabeyama region of the Kwanto massif, near 
Tokyo, and, hence, the Nabeyaman series and 
epoch are here proposed respectively for the time- 
rock and time units of the Parafusulina zone in 
Japan. 

Limestone conglomerates and conglomerates 
containing various kinds of rocks as pebbles have 
been found in many places in Japan, many of 
which are considered to be equivalent in age to 
the Parafusulina zone. Because of their stra- 
tigraphical and tectonical significance future 
studies on these conglomerates seem to be very 
important. 

8. Neoschwagerina-Verbeekina zone: Correla- 
tion of the Neoschwagerina-Verbeekina zone 
of East Asia with the Russian divisions of the 
type Permian has not been satisfactorily estab- 
lished. Quoting from Kahler's result (21), 
Minato (22) recently distinguished the Neosch- 
wagerina facies of Southeast Asia and the non- 
Neoschwagerina facies of the Mongolian geosyn- 
cline. Southwest Japan is considered to be the 
boundary area between these two facies. 

The Akasaka limestone of Central Japan forms 
ihebesiexposureofiheNeoschwagerina-Verbeekina 
zone in East Asia, which was divided by Ozawa 
* into four subzones. It is probable that the 
Ozawa's Nn subzone is equivalent in age to a 
part of the Parafusulina zone of Nabeyama and 
other places. 

The terms Akasakan scries and epoch are also 
proposed respectively for the timerock and time 
units of the Neoschwagerina-Verbeekina zone of 
Japan. 

9. Yabeina-Lepidolina zone : Correlation of the 
Yabeina-Lepidolina zone has been still uncertain 
even in the Japanese islands. Kanmera (23) 
emphasized the stratigraphical and paleontolo- 
gical significance of the Kuma series of Kyushu, 
fusulinid fauna of which is characterized by the 
advanced forms of Yabeina and Lepidolina. Simi- 
lar conglomerate-bearing formations have been 



reported from many localities in Japan. Outside 
of Japan, the Upper Permian formation of Cam- 
bodge (24) and the Toman Formation (25) of 
Northern Manchuria are certainly correlated 
with the Kuman scries, and the Palcofusulina 
zone of Changhsing limestone (26) and Codono- 
fusiella zone of Wuchiaping limestone (27) are 
seemingly referable to the Kuman series. 



REFERENCES 

(1) Yabe, H., 1949, Proc. Japan Acad., 24: 

165-167. 

(2) Kanmera, K., 1952, Mem. Fac. Sci. , Kvushu 

Univ., Ser. D., 3 (4): 157- 177. 

(3) Igo, H., 1956, Jour. Geol Soc. Japan, 62 

(278): 2 17-240. 

(4) Minato, M., 1950, Ditto., 56(658):379-382. 

(5) Toriyama, R., 1954, Mem. Fac. Sci., Kvushu 

Univ., Scr.D., 4(l):39-97. 

(6) Toriyama, R., 1953, Jour. Paleont., 27 (2): 

251-256. 

(7) Onuki, Y. and Yamada, Y., 1955, Jour. 

Geol. Soc. Japan, 61 (718) : 305. 

(8) Kanmera, K., 1954, Japan. Jour. Geol. 

Geogr. 25(1-2) : 117- 144. 

(9) Kanuma, M., 1951, Jour. Geol. Soc. Japan, 

57 (670) : 266. 

(10) Fujimoto, H. and Igo, H., 1955, Trans. Proc. 

Paleont. Soc. Japan, N.S. 18 : 45-48. 

(11) Fujimoto, H. and Kawada, S., 1951, Jour. 

Geol. Soc. Japan, 57 (670) : 266. 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

(12) Kanmera, K., 1952, Ditto., 58 (676): 17-37. 

(13) Morikawa, R., 1953, Sci. Rep. Saitama 

Univ., Ser.B, 1 (2) : 115- 122. 

(14) Kanmera, K., 1955, Japan. Jour. Geol. 

Geogr. 27(3-4) : 177-192. 

(15) Saurin, E., 1950, Bull. Serv. Geol. Indochina, 

29(5). 

(16) Saurin, E., 1954, Archives %eol. Viet-nam, 

1:1-30. 

(17) Konishi, K., 1953, Trans. Proc. Paleont. 

Soc. Japan, N.S., 12:103-110. 

(18) Fujimoto, H. and Kanuma, M., 1953, Jour. 

Paleont. 27(1): 150-152. 

(19) Fujimoto, H. and Kawada, S., 1953, Sci. 

Rep. Tokvo Bunrika Daigaku, Sec.C, 2 
(13): 207-209. 

(20) Kanmera, K., 1956, Trans. Proc. Paleont. 

Soc. Japan, N.S., 24:251-257. 

(21) Kahler, K, 1939. Senckenbergiana. 21: 

169-215. 

(22) Minato, M., 1956, Earth Science 28: 1-13. 

(23) Kanmera, K., 1954, Mem. Fac. Sci. Kvushu 

Univ., Scr. D, 4 (1): 1-38. 

(24) Gubler, J., 1935, Mem. Soc. Geol. France, 

N.S. (4): 1-171. 

(25) Moda, M., 1956, Rep. Earth Sci. Dep. 

General Educ. Kyushu Univ., 2: 1-22. 

(26) Sheng, J., 1956, Acta Paleont. Sinica, 4(2): 

175-228. 

(27) Sheng, J., 1955, Acta Paleont. Sinica, 3 (4): 

287-308. 



253 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



FORAM1NIFERA IN AUSTRALIAN PERMIAN STRATIGRAPHY 

I. CRESPIN 

Canberra, Australia. 

(Abstract) 



During the last few years Permian stratigraphy 
in Australia has received considerable attention 
from geologists engaged in the search for oil and 
coal. Many lithological units have been recog- 
nised, the majority of them containing charac- 
teristic foraminiferal assemblages. 

Investigations in Western Australia have 
proved the record of Fusulinids (Chapman and 
Parr, 1 937) in the deposits of the Fitzroy Basin 
to be incorrect. The beds are Triassic, not 
Permian, in age and the "Fusulinids" probably 
fish remains. 

Publications on Australian Permian foramini- 
fera are few; the most recent contribution is by 
Crespin and Belford (1957) in which two new 
genera of the family Opthalmidiidae, Streblospira 
and Electospira, have been described from Western 
Australia. 

With the detailed geological work, changes in 
stratigraphical nomenclature in Australian Per- 
mian deposits have been necessary. Old names 
such as "Lower Marine Series" and "Upper 
Marine Series" of New South Wales stratigraphy 
have been superseded by rock-unit names in 
conformity with the Australian Code of Strati- 
graphic Nomenclature. 

Extensive deposits of Permian marine rocks 
are known from all parts of Australia except 
Victoria and South Australia. Recently Permian 
foraminifera were found in a bore on Yorke 
Peninsula, South Australia (Ludbrook, 1957), 
but so far none have been discovered in Victoria. 
The present paper gives a summary of Permian 
stratigraphy in Queensland, New South Wales, 
Tasmania and Western Australia. The formations 



are listed in stratigraphical sequence and charac- 
teristic foraminifera are noted from those for- 
mations in which they have been recorded. New 
genera arid species are listed as manuscript 
names; these will be described shortly in a 
Bureau Bulletin by the writer. Comments are 
given on genera and species found. The assem- 
blages in subsurface deposits are characterised 
by numerous tests of the family Lagenidae, 
including Nodosaria, Dentalina, Frondicularia, 
Lingulina, Geinitzina and Lenticulina (Astacolus}. 
Arenaceous species dominate all outcrop de- 
posits, except those in the Mantuan Productus 
Bed, Springsure area, Queensland and in the 
Fossil Cliff Formation, Irwin Basin, and Cally- 
tharra Formation, Carnarvon Basin, Western 
Australia. Calcareous imperforate forms are 
common in the last two formations. Some 
species from the Pennsylvanian and Permian 
deposits of United States and from the upper 
Carboniferous and Permian of Europe have been 
determined. Eight foraminiferal assemblages 
have been recognised in the Australian Permian 
deposits; these should be useful in stratigraphical 
work. 

Australian stratigraphers and palaeontologists 
are not agreed on the basis for the division of the 
Permian System into lower, middle and upper 
Permian and whether the Sakmarian Stage of 
Europe should be included in the lower Permian 
~or in the upper Carboniferous. With the absence 
of Fusulinids in Australia, little evidence is given 
by the foraminifera for correlation with Euro- 
pean Stages. However, the larger fossils have 
yielded certain reliable data. 



254 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



RECENT ADVANCES IN THE CORRELATION OF NEW ZEALAND 
PALEOZOIC AND LOWER MESOZOIC SEDIMENTS 

C. A. FLEMING 

M J M- Zealand Geological Survey* Wellington, New Zealand. 



This paper summarises some of the knowledge 
gained since the Eighth Pacific Science Congress 
(1953) on the correlation of New Zealand Paleo- 
zoic, Triassic and Jurassic rocks. 



PALEOZOIC 



CAMBRIAN 



The discovery of the first Cambrian fossils 
in New Zealand was briefly announced by Ben- 
son (1952) at the 7th. Pacific Science Congress. 
Benson has subsequently (1956) published a 
preliminary note listing agnostid trilobites of the 
genera Peronopsis, Hypagnostus, Plychagnostus, 
Phoidagnostus, and Oidalagnostus, identified by 
Dr. O.P. Singleton, and non-agnostids Dorypyge, 
"Amphoton'\ Solenoparia, ? Solenopleura, ? 
Anomocare, and a Koptura-likc genus, identified 
by Dr. Singleton and Dr. A.A.Opik. The tri- 
lobites have affinities with those of Manchuria, 
the Baltic region and especially western Queen- 
sland, and are dated as late Middle Cambrian. 
Benson also listed a rich microfauna obtained by 
Dr. F.H.T. Rhodes by acetic acid digestion, 
including sponges, brachiopods, gastropods, 
brachiopods and ostracods. 

ORDOVICIAN 

Field work in the Cobb River Mount Arthur 
region (Nelson) and in the Preservation Inlet 
Cape Providence area (Fiordland) has resulted in 
new collections of Ordovician graptolites, but no 
results are yet available. Decker (1952) has 
recorded many New Zealand species of grap- 
tolites from the Athens Shale of U.S.A. 

DEVONIAN 

The standard section of New Zealand Middle 
and Lower Devonian sediments at Reefton has 
been remapped and the structure of the Devonian 
outliers re-interpreted by Suggate (1957). The 
Lower Devonian Reefton mudstone (about 
Coblenzian) of which the brachiopod fauna was 
revised by Allan (1947) has yielded further fos- 
sils, including a carpoid echinoderm and a new 
genus of Solenomorph lamellibranch, Paleodora 



Fleming (1957). Gill (1953) has discussed the 
relationship of Australian, New Zealand and 
North African Lower Devonian faunas. 

Devonian corals of the Reefton area have been 
revised by D. Hill (1956). A new genus Tiphe- 
ophyllum (type species, EridophyUum hart rum i 
Allan) and two new species (Hexagonaria allanl 
and Thatnnopora reeftonensis) were described. 
Two species (T. bartrumi and Favosites murrum- 
bidgeensis Allan) are common to Reefton and 
Australia. The age of the Reefton Limestone is 
assessed as early Couvinian or perhaps topmost 
Emsian. 

Poorly preserved brachiopods above the Middle 
Devonian coral horizon have long been known to 
include "Megantcris" (\.z. Beachia)cf. neozelanica 
Allan, suggesting Lower Devonian age. Recently 
E.D. Gill (in Suggate 1957) recognised Fascicos- 
tella aff. gcrvillei (Defrancc), a Lower Devonian 
species of a genus unknown in the Australian 
Middle Devonian (but ranging up to Couvinian 
elsewhere), from a horizon 40-50 ft. above the 
Middle Devonian coral limestone at Reefton. 
Further collecting and study is necessary to 
resolve such conflict of evidence. 



CARBONIFEROUS 

In several recent discussions of the mighty 
pile of Upper Paleozoic sediments overlying the 
Otago Schist in the New Zealand Geosyncline, 
the terms "? Carboniferous" (Wood, 1956:17), 
"probably Carboniferous" (Wellman, 1956:24) 
or "Carboniferous" (Mutch, 1957 :502) are applied 
to rocks underlying the Lower Permian Maitai 
Series. It is important to emphasize that no 
Carboniferous fossils have yet been determined 
from New Zealand, and what little fossil evidence 
is available from the pre-Maitai rocks (Maitai 
from the Waipahi Group; Euryphyllum(l) from 
the Takitimu Group) favours Permian rather 
than Carboniferous age. New collections made 
by A.R. Mutch from the Takitimu Group are 
being studied by J.B. Waterhouse in Cambridge, 
but no results are yet available. 

255 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



PERMIAN 

New fossil collections have been made from 
the beds in Southland (Productus Creek Group) 
and Nelson which provided faunas determined as 
Artinskian, closely related to those of the Upper 
Marine Series (Branxton Stage) of New South 
Wales (Fletcher, Hill & Willett, 1952), and are 
being studied by J.B. Waterhouse; this work, as 
yet incomplete, will greatly increase the list of 
Lower Permian fossils (particularly Brachiopoda) 
known from New Zealand. McQueen (1954) has 
described the first Permian fossil plants from 
New Zealand, which include Noeggerraihiopsis 
hislopii (Bunbury) and resemble those of the 
Bowen Series, Queensland. 

Leed (1956) has fully described Upper Per- 
main Reef-building corals which accompany the 
fusulines Neoschwagcrina margaritac Deprat, N. 
mtthisepta Deprat, Verbeckina sp. and Gahcina 
sp. (Hornibrook, 1951) in certain North Auck- 
land limestones. Two coral species are recog- 
nised, Waagenophyllwn novaezelandiae Leed and 
Wentzelella maoria Leed, the former closely 
related to a form from the Capitanian of Texas, 
the latter species from the Salt Range of Kashmir. 
They represent a strong and previously unsus- 
pected Tethyan element in New Zealand Permian 
and from their affinities indicate Capitanian- 
Ochoan age. 

MESOZO1C 

TRIASSIC 

The stimulus provided by Marwick's (1953a) 
revision of faunas and divisions of the Hokonui 
System (Triassic and Jurassic) has led to much 
new work in field and laboratory on Triassic 
geology and fossils. Field studies of important 
Triassic sections have been contributed by 
Coombs (1950, 1954), Watters (1952), Campbell 
(1955, 1956) and Campbell & McKellar (1956), 
the last three papers being detailed descriptions of 
sequence and fauna in the Oretian and Otapirian 
Stages (approximately Lower Carnian & Rhae- 
tian) throughout New Zealand. The thick poorly 
fossiliferous greywacke-argillite rocks that form 
the Southern Alps have provided Norian Monotis 
at several new localities (Wellman, Grindley & 
Munden, 1952) and a Carnian (?) Palaeoneilo 
(Fleming, Munden & Suggate, 1954). Campbell 
& Warren (1955) relocated and described Norian 
limestones from Okuku, North Canterbury, 
containing abundant Monotis richmondiana Zit- 
tel & M. Calvata Marwick, also brachiopods and 
polyzoans. Wood (1953, and 1956) and Mutch 

256 



(1957) have contributed descriptions and dis- 
cussions of the stratigraphy and structure of the 
southern end of the New Zealand geosyncline, in 
which thick Trinssic sediments accumulated. 
J.D. Campbell is working on the systematics of 
the Oishintive N.Z. Triassic Brachiopod fauna. 

The most notable recent advance in correlation 
of the New Zealand Trias has been the identifica- 
tion by Dr. B. Kummel, Harvard (pers. conim.) 
of several ammonites, collected by Mr. A.R. 
Mutch from the Lower Gore Series of Western 
Southland, as mid Scythian forms of the Owenites 
Zone. Hitherto, the Anision, represented by 
Parapopanoceras ( =Becwmontites Browne, sec 
Kummel, 1955) and other ammonites of the 
New Zealand Etalian Stage, has been the oldest 
Triassic known in this country. 

Kummel (1953) has also described the New 
Zealand Carnian nautiloid Bisyphyies trcchnmnni 
(^Grypoceras cf. mcsodicum (Hauer), of Trech- 
mann) and discussed its significance in nautiloid 
evolution. Comparisons of Triassic Mollusca of 
Japan and New Zealand are found in papers by 
Kobayashi (1954), Ichikawa (1954) and Kobayashi 
& Ichikawa (1952). Marwick (1953 b) analysed 
Triassic and Jurassic faunas from the point of 
view of faunal migration and routes, endemism 
and isolation. "At no age, from Anisian to Titho- 
nian, was ammonite immigration barred from 
New Zealand seas, though it was evidently limited 
by geographic factors." 

Routhier (1953) and Avias (1953) have greatly 
strengthened the paleontological links between 
the Trias of New Zealand and New Caledonia, 
the latter recording such distinctive New Zealand 
Brachiopods as Clavigera* Mentzeliopsis, Spin'- 
ferina laihikuana Trechmann, and Rastelligera 
from the New Caledonian Trias (described by 
Mile. J. Drot, in Avias, 1953). 

JURASSIC 

Several of the papers cited in the preceding 
section deal with Jurassic as well as Triassic 
problems (Marwick, 1952 a, b.; Watters, 1952; 
Wood, 1956; Routhier, 1953; Avias, 1953). As 
with the Triassic, Marwick's revision (1953 a) 
has greatly stimulated further work on important 
sections, especially in the Kawhia region (Kear 
& Fleming, unpublished) and in Southland 
(I.C.McKellar; I.G. Speden, in prep.). Ammo- 
nites found in the course of these projects will 
greatly improve Jurassic correlations, but few 
determinations are available for citation at 
present. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



From the Hokonui Hills, Southland, Arkell 
(1953) has identified Ectocentrites cf. peter si 
Hauer (Hettangian) from a horizon now known 
to be higher than that ofPsiloceras spp. previously 
recorded from that area. In 1956, G.R.Stevens 
identified the first New Zealand specimens of the 
Upper Hettangian zonal ammonite Schlotheimia 
cf. angulata from the well known Flag Hill section, 
and recognised in old collections a specimen of 
Coroniceras from the same area the first ammo- 
nite evidence of Sinemurian in the Lias of the 
Hokonui Hills (Anon. 1957). 

From beds at Totara Peninsula, Kawhia, which 
Marwick (1951) first included in his Heterian 
Stage, but later (1953) in the underlying Temaikan, 
Arkell (1956, p. 455) has determined Idoceras 
cf. humboldti Burchkardt, Epicephalites cf. epigo- 
nus Burckhardt, and Subneumayria, Lower Ki- 
meridgian forms of strongly Mexican affinity. 
The indications of Himalayan and European 
Bajocian-Bathonian affinity which Marwick found 
in the Pelecypoda and Brachiopoda from this 
(or, in fact, a slightly higher) horizon are thus 
deceptive. Arkell (1953) has also demonstrated 
the presence of the Mexican genus Idoceras in 
the South Island. Field work has recently 
clarified the relationship between the thick 
Kimeridgian sequence on the north shore of 
Kawhia and the ammonite horizon at Puti 
Point on the north shore which has yielded an 
ammonite assemblage (Aulacosphinctoides, Uhligi- 
tes, etc.) reminiscent of the Middle Spiti Shales 
(Lower Tithonian). Dr. Arkell is undertaking 
study of the ammonite succession in the Kawhia 
section, which promises to contribute to the 
solution of zonal correlations elsewhere in the 
Tethyan region. 

Hornibrook (1953) has described a small 
Jurassic foraminiferal fauna from an oil pros- 
pecting well in North Taranaki, including Lingu- 
lina evansi Hornibrook, closely related to L. 
lenera Bornemann (Jurassic of Europe). Fell 
(1954) has described the first known New Zealand 
Jurassic Asterozoan, Odont aster prescies Fell 
from the Temaikan stage. Couper (1953) has 
recorded the pollen grains and spores from 
certain non-marine beds, attributed to Upper 
Jurassic, in Westland and southwest Nelson, 
west of the areas of marine Jurassic sedimenta- 
tion. 

REFERENCES 

Allan, R.S., 1947, A Revision of the Brachio- 
poda of the Lower Devonian Strata of 



Reefton, New Zealand. J. Paleont. 

21(5):436-452. 
Anon., 1957, McKay Hammer Award, 1956, 

GeoL Soc. N.Z. Newsletter, 4:8. 
Arkell, W.J., 1953, Two Jurassic Ammonites 

from South Island, New Zealand, and 

a Note on the Pacific Ocean in the 

Jurassic. N.Z. J. Sci. Tech. B 35(3): 

259-64. 

----- ^ 1956, Jurassic Geology of the 
World (Oliver & Boyd, Edinburgh and 
London). 

Avias, J., 1953, Contribution a FEtude Strati- 
graphique et Paleontologique des 
formations Antecretacees de la Nou- 
velle Caledonie Centrale. Science de 
la Terre. \ (1-2). 

Benson, W.N., 1952, Meeting of the Geological 
Division of the Pacific Science Congress 
in New Zealand, February, 1949. In- 
terim Proc. %eol, Soc. America, 1950 1: 
11-13. 

Benson, W.N., 1956, Cambrian Rocks and 
Fossils in New Zealand (Preliminary 
Note). In: El Sy sterna Cambrico, su 
Paleogeographia y el Problema de su 
Base, XX. Congr. GeoL Intern. 2 (2): 
285-8. 

Campbell, J.D., 1955, The Oretian Stage of the 
New Zealand Triassic System. Trans. 
roy. Soc. N.Z. 82 (5) : 1033-47. 



? 1957 ? The Otapirian State of the 
Triassic System of New Zealand. Part II. 
Ibid., 84(1) : 45-50. 

Campbell, J.D. and McKellar, I.C., 1956, The 
Otapirian Stage of the Triassic System 
of New Zealand. Part I. Ibid., 83 (4): 
695-704. 

Campbell, J.D. and Warren, G., 1955, A Note on 
Upper Triassic Limestone from the 
Okuku Valley, North Canterbury. N.Z. 
J. Scl. Tech. B36(5) : 531-2. 

Coombs, D.S., 1950, The Geology of the 
Northern Taringatara Hills, South- 
land. Trans, rov. Soc. N.Z. 78 (4): 
426-48. 

-- , 1954, The Nature and Alteration 
of Some Triassic Sediments from South- 
land, New Zealand. Ibid., 82: 65-109. 

Couper, R.A., 1953, Upper Mesozoic and Cai- 
nozoic Spores and Pollen Grains from 
New Zealand. N.Z. GeoL Surv. Pal., 
Bull. 22. 

257 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Decker, C.E., 1952, Stratigraphic Significance of 

Graptolites of Athens Shale. Amer. 

Assoc. Petr. Gcol. 36 (1): 1-145. 
Fell, H.B., 1954, New Zealand Fossil Asterozoa. 

3. Odontaster prescies sp. nov. from 

the Jurassic. Trans, roy. Soc. N.Z. 82: 

817-19. 
Fleming, C.A., 1957, A New Devonian Lamel- 

libranch from Reefton, New Zealand. 

Ibid. 



Fleming, C.A., Munden, F.W. and Suggate, R.P., 

1954, An Upper Triassic Lamelli- 

branch from the Southern Alps of North 

Westland, New Zealand. Ibid. 82 (1): 

111-114. 
Fletcher, H.O.; Hill, D.; Willett, R.W., 1952, 

Permian Fossils from Southland. N.Z. 

Geol. Surv. Pal. Bull. 19. 
Gill, E.D., 1953, Relationship of the Australa- 

sian and North African Devonian 

Faunas. Proc. 19th. Internal, geol. Congr. 

Sec. 2(2): 87-92. 
Hill, D., 1956, The Devonian Corals of Reefton, 

New Zealand. N.Z. geol. Surv. Pal, 

Bull. 25: 1-14. 
Hornibrook, N. de B., 1951, Permian Fusulinid 

Foraminifera from North Auckland 

Peninsula, New Zealand. Trans, roy. 

Soc. N.Z. 79: 319-21. 
____ . ___ , 1953, Jurassic Foraminifera from 

New Zealand. Ibid 81: 375-8. 
Ichikawa, K., 1954, Late Triassic Pelecypods 

from the Kochigatani Group . . . .II. 

/. Inst. Polyt. Osaka, Ser. G. 2:53-75. 
Kobayashi, T., 1954, Studies on the Jurassic 

Trigonias in Japan. Part I. Jap J. Geol. 

Geog. 25:61-80. 
Kobayashi, T. and Ichikawa, K., 1952, Triassic 

Fauna of the Heki Formation. . . Ibid. 

22:55-84. 
Kummel, B., 1953a, The Ancestry of the Family 

Nautilidae. Breviora, Mus. Comp Zool. 

21, 7 pp. 
__ , 1953b, Middle Triassic Ammonites 



from Peary Land. Med. om Gronland 
127(1): 1-21. 

Leed, H., 1956, Permian Reef-building Corals 
from North Auckland Peninsula, New 
Zealand. N.Z. geol. Surv. Pal. Bull. 25: 
15-23. 

McQueen, D.R., 1954, Upper Paleozoic Plant 
Fossils from South Island, New Zea- 
land. Trans, roy. Soc. N.Z. 82: 231-6. 

Marwick, J., 1951, Series and Stage Divisions of 
New Zealand Triassic and Jurassic 
Rocks. N.Z. J. Sci. Tech. 32 (3): 8-10. 

__, 1953a, Divisions and Faunas of the 

Hokonui System (Triassic and Jurassic). 
N.Z. geol. Surv. Pal., Bull. 21. 

__ , 1953b, Faunal Migrations in New 

Zealand During the Triassic and Juras- 
sic. N.ZJ. Sci. Tech. 34: 317-21. 

Mutch, A.R., 1957, Facies and Thickness of the 
Upper Paleozoic and Triassic Sedi- 
ments of Southland. Trans, rov. Soc. 
N.Z. 84(3): 499-511. 

Routhier, P., 1953, Etude Geologique du Versant 
Occidental de la Nouvelle Caledonie ... 
Mem. Soc. geol. Fr. 67 (n.s.). 

Suggate, R.P., 1957, The Geology of Reefton 
Subdivision. N.Z. geol. Surv. 56. 

Watters, W.A., 1952, The Geology of the Eastern 
Hokonui Hills, Southland. Trans, rov. 
Soc. N.Z. 79: 467-84. 

Wellman, H.W., 1956, Structural Outline of 
New Zealand. N.Z. Dep. Sci. ind. Res. 
121. 

Wellman, H.W., Grindley, G.W. and Munden, 
F.W., 1952, The Alpine Schists and the 
Upper Triassic of Harpers Pass (S52), 
South Island, New Zealand. Trans, 
roy. Soc. N.Z. 80: 213-27. 

Wood, B.L., 1953, Paleozoic and Mesozoic 
Stratigraphy and Structure in Southland. 
Roy. Soc. N.Z. Rep. 7th Sci. Congr.: 
106-14. 

, 1956, The Geology of the Gore Sub- 
division. N.Z. geol. Surv. 53. 



258 



VOLUME 



GEOLOGY AND GEOPHYSICS 



THE OCCURRENCE OF A JURASSIC AMMONITE, 
RECENTLY FOUND IN TAIWAN, CHINA 



C. C. LIN 

Department of Geology, National Taiwan University, Taipei, Taiwan, Republic of China. 



A Phylloceratinid Ammonite was obtained 
from the bore hole of PK No. 2 well sunk by the 
China Petroleum Corporation (CPC) at about 
two km. south of Ssuhu near Peikang. Chiayih- 
sien, Taiwan. The fossil Phylloceratina was 
found preserved in the hard, compact fine- 
grained, carbonaceous sandstone of the boring 
core from the depth of 1692.8 m. This phyllo- 
ceratinid fossil was lent to me for study by 
CPC along with some illpreserved Belemnites, 
Pelecypods, Brachiopods, plants and a few frag- 
ments of another kind of Ammonite from differ- 
ent depths of the same well. The occurrence of 
Jurassic fossils is quite new to science in Taiwan. 

DESCRIPTION 

Family : Phylloceratidae Zittel 
Subfamily: Calliphylloceratinac Spath 
Genus: Holcophylloceras Spath, 1927 

Holcophylloceras aff. mediterraneum 

(Neumayr) 
(Plate 1, Figures 1-5.) 

MATERIAL 

Only a single specimen was obtained in the 
boring core; it is relatively well preserved, but 
the shell is compressed, and partly broken or 
deformed. The specimen is stained with a black 
color by carbonaceous materials. As some of the 
inner parts are cemented by hematite, we find the 
shape of the suture lines relatively clear from its 
reddish color. The apertural part and outer 
margin of its body chamber were damaged by the 
boring bit. 

DESCRIPTION 

The shell is involute and flattened, with a 
sharp, angular siphonal part due to compression. 
The shell itself is provided with six constrictions 
on each whorl, which are deeply cut in at the 
siphonal part, and continue as a straight or 
slightly curved or indistinctly line. These con- 
strictions are somewhat broad and shallow at the 
middle of the height of each whorl. Most part of 



the surface of the shell is smooth, but there exist 
fine filiform ribs on the siphonal side of the shell 
between the constrictions. The umbilicus is 
narrow. 

The suture lines are generally similar in shape 
to those of most specimens of //. mediterraneum 
figured by Waagen and some of H. aff. poly- 
oleum (Beneck), figured by Spath. The external 
saddle is diphyllitic and the first lateral saddle 
triphyllitic, and every branch of these has a 
round apex. I am sorry I have not seen the 
figure of Neumayer's in his original paper, but 
according to Waagen, the lobes of his Indian 
specimen seems a little more finely divided on the 
whole than those in Neumayr's figure; I can only 
say that relative to the Indian specimen, the 
lobes of the Taiwan specimen seems a little more 
coarsely (and simply) divided. 

DIMENSIONS 

The specimen is not complete; but from the 
restored figure, we know the diameter of last 
whorl that is preserved is about 47 mm.; the 
diameter of the umbilicus is 7-8 mm. (17%); the 
height off the last whorl is 1 5 mm. ; the width of 
the last whorl about 5-6 mm. The diameter of 
Neumayr's holotype is 115 mm., of his other 
specimens 129 mm, and 102 mm.; of Waagen's 
Cutch specimens 70 mm., 1 10 mm. and 165 mm. ; 
of Lemoine's specimen 70 mm., of Spath's spec- 
imens 197 mm. The Taiwan specimen is small 
compared to these. 

REMARKS 

"Phylloceras" mediterraneum is a well 
founded and easily recognizable species. Spath 
established the genus Holcophylloceras in 1927, 
and selected this species as its genotype. The 
surface character of the Taiwan specimen is 
quite similar to E. Koken's figure (fig. 52) of 
"Phylloceras" mediterraneum, in his "Die Leit- 
fossilien" p. 73, except for the number and shape 
of constrictions. But the character of the con- 
strictions may not be the dicidedly important 
character in this species. Spath said: "It should 
be mentioned that a compressed example of 
the present species (H. mediterraneum), with only 
five constrictions at 125 mm. diameter has now 
been found by Mr. J.H. Smith in the Katrol 

259 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Plate 1. Jurassic Ammonite from Taiwan. 



260 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Beds of Fakirwadi. Since there occur transitions 
to H. polyolcum already in the Callovian, it will 
be seen that a new specific name for the forms 
intermediate between H. mediterraneum and 
H. polyolcum (in the number of constrictions) 
would not even be of stratigraphical value." 
And it is difficult to separate immature examples 
of H. polyolcum from H. mediterraneum only 
by their constrictions. Anyway the number and 
shape of constrictions of the Taiwan specimen 
are somewhat different with the others, and more 
similar to the constrictions of Calliphylloceras 
aff. demidorffi (Rousseau) from bed No. 6 of 
Khera Hill, and of the immature specimen of 
H. aff. polyolcum from Katrol Beds, Kimmerid- 
gian, of Fakirwadi ; both were figured by Spath. 

The suture lines of the Taiwan specimen agree 
typically with those of H. mediterraneum figured 
by Waagen and some of H. aff. polyolcum, figured 
by Spath, the external saddle being diphyllitic, 
the first lateral saddle triphyllitic and the second 
and third (?) ones also diphyllitic. Suture lines 
of//, aff. polyolcum of PI. VI, fig. 2e and PI. VII, 
fig. 5 in Spath's monograph agree most with those 
of our specimen. 

Although Spath gave the name "H. aff. polyol- 
cum" to the thirty-five specimens of Hocophyl- 
loceras from the Kimmeridgian Katrol Series of 
Cutch, I believe some of them should be included 
in H. mediterraneum from his description and 
figures. So my specific range of //. mediterra- 
neum is somewhat wider than according to the 
opinion of Spath and includes Spath's H. medi- 
terraneum from Callovian Chari Series and some 
of his //. aff. polyolcum from Kimmeridgian 
Katrol Series of the Cutch Region. 

As there remain some questions: such as, 
number and shape of constrictions or separation 
of mediterraneum and aff. polyolcum, etc. I 
propose temporarily the name of H. aff. mediter- 
raneum for the Taiwan specimen. 

LOCALITY 

As already mentioned in the introduction, 
this Holcophylloceras aff. mediterraneum was 



obtained from a depth of 1691.8 m from the 
boring core of PK No. 2 Well, sunk by China 
Pepteleum Corporation, during Feb. 14 to June 
13 this year (1957), at two kilometer south of 
Ssuhu near Peikang town, Chiayihsien. 

GEOLOGICAL AGE 

H. mediterraneum is one of the most common 
Ammonites in the Tethys province including 
Uhlig's "Mediterran-Kaukasisches Reich" and 
"Himalajisches Reich", etc., in Jurassic Paleo- 
geography. In Europe this species has a very 
large vertical distribution, and ranges from 
Bathonian up to the uppermost Jurassic. (Prinz, 
1904, said this species begins already in the 
Lower Bajocian.) 

In the "Himalajisches Reich" this species 
occurs abundantly in the Callovian anceps zone 
of the Chari Group and the Kimmeridgian 
Katrol Beds. 

ACKNOWLEDGEMENT 

Thanks are due to the authorities of the 
China Petroleum Corporation for giving me the 
opportunity to study the first specimen of a 
Jurassic fossil from Taiwan. 

REFERENCES 

Koken, Ernst, 1896, Die Leitfossilien, Leipzig. 
Spath, L.H., 1927, Revision of the Jurassic 

Cephalopod Fauna off Katch (Kachh), 

Pal Ind., New Ser. 9 (2): 60. 
Op. Cit. (2), PI. VII, fig. 8 (Calliphylloceras aff. 

demidoffi) and Fig. 5 (Holcophylloceras 

aff. polyolcum). 
Waagen, William, 1937, Jurassic Fauna of 

Cutch, vol. I, The Cephalopoda, Pal 

lnd. 9 9: (1-4). 
Uhlig, I, 1911, Die marine Reiche des Jura und 

der Unterkreide, Mitt. Wien GeoL 

Ges. 4. 



EXPLANATION OF PLATE 

Holcophylloceras aff. mediterraneum (Neumayr) 

Figures 1 and 2. Deformed specimen, preserved in boring 

core. Side view 1/1. 
Figure 3. Front view. 1/1. 
Figure 4. Restored figure. 1/1. 
Figure 5. Suture line, largely magnified. 



261 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



THE JURASSIC OF JAPAN AND ITS BEARING 
ON THE CORRELATION 

TEIICHI KOBAYASHI 

Geological Institute, University of Tokyo, Tokyo, Japan. 



In Japan the Jurassic was the transitional 
period between the Triassic Akiyoshi and Cretace- 
ous Sakawa orogeny, and her palaeogeography 
is highly complicated. In the Akiyoshi folded 
mountains on the continental side there was a 
series of basins along the boundary between the 
Sangun metamorphosed zone and the Yamaguchi 
folded zone (See map). These basins were 
separated from the Pacific Ocean by the so- 
called Eo-Nippon Cordillera which is the embryo- 
nic geanticline of the growing Sakawa moun- 
tains. Such a great variability of geographic 
import is indicated by the tremendous variation 
of sediments in facies and thickness and the 
fossils therein. The Jurassic stratigraphy and 
paleontology of Japan were greatly improved 
in recent years with the result that the Jurassic 
areas are now classifiable as follows : 

I. The chain of basins in the Akiyoshi hinterland, 
where the nerito-paralic sediments were accumu- 
lated to a great thickness. 

la. The Kuruma, Iwamuro and Yamaoku basins 
(8,9 and 3 in map respectively) prolific in Rhaeto- 
Liassic plants and various pelecypods of which the 
latter show that the three basins were confluent. 
The Kuruma series measures several thousand 
meters in thickness and yields Liassic ammonites 
in three beds. (According to Kobayashi, Ko- 
nishi, Ta. Kimura, Sato, Hayami.). 

Ib. The Tetori, Kuzuryu, Jinzu and Furukawa 
areas (4, 5, 6, 7). The Tetori series there has 
been considered Upper or Middle Jurassic, but 
with the find of the Omichidani flora containing 
Dicotyledonous plants it is known now to con- 
sist of the Limnic Akaiwa formation of Middle 
Cretaceous age, the paralic Itoshiro formation of 
Upper Jurassic to Lower Cretaceous and the 
Middle (?) and Upper Jurassic Kuzuryu forma- 
tion, mostly neritic. They are separated by 
local disconformities. The so-called Tetori 
flora is contained in the Itoshiro and Kuzuryu 
formations. The thickness of the Jurassic part is 
about 1,000 m. (Kobayashi, Kawai, Maeda, 
et al.) 

Ic. The Toy or a and Toyonishi basins (2, 1). 
The Toyora series of the former basin consists 
of marine sediments of about 1,000 meters 

262 



thickness in an embayment which reveals a cycle 
of sedimentation from Hettangian to Callovian. 
It is unconformably overlain by the paralic Toyo- 
nishi series on the west side which is an orogenic 
type of sediment (Matsumoto and Ono.) 

II. The northern marginal depressions of the 
Bo-Nippon Cordillera. In the southern Kitakami 
mountains are two synclines which were narrow 
parallel embayments. The Jurassic strip of 
Soma on the eastern foothills of the Abukuma 
mountains belong to the epiric sea of the Pacific 
Ocean. 

Ila. The Shtzukawa embayment comprising the 
Shizukawa, Hashiura and Mizunuma areas (11, 
12, 13). There exist most stages from Hettangian 
to Tithonian, but the sequence is interrupted by 
one or two disconformities. The total thickness is 
about 1,000 m. where the Lias occupies only 
150 m. or so. (Matsumoto, Ono, Mori, and Sato). 

lib. TV Ojika embayment including the Ojika 
peninsula and Karakuwa area (14, 15) where the 
sedimentation was commenced after Aelenian. 
Nevertheless the thickness attains more than 
1,500m. (Onuki, Oyama, Fukada, Sato). 

He. The Jurassic strip of Soma (16). Although 
the base is unexposed, the Middle and Upper 
Jurassic formations attain more than 1,500 m. 
The major part belongs to the shallow open-sea 
facies and a reef-limestone layer is intercalated. 
(To. Kimura, Masatani, Tamura). 

III. Geosynclines. While there was vigorous 
"Volcanism in the Yezo geosyncline in Hokkaido 

in the Jurassic and early Cretaceous periods, it 
is imperceptible in the Shimanto geosyncline 
from the Kwanto region to South Kyushu. 

Ilia. The near-shore zone of the Shimanto 
geosyncline where the Torinosu series containing 
bioherms is extensive and disconformably over- 
lies the Sambosan group which is mostly Permo- 
Triassic. At a few places, however, Lower or 
Middle Jurassic brachiopods are found near the 
top. The Torinosu series is about 500 m. thick 
at the type locality in the Sakawa basin. (18, To. 
Kimura). 

Illb. The off-shore zone of the Shimanto geosyn- 
cline. The Shimanto group is an unbroken series 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



from Lower Cretaceous to Triassic or Permian. 
It is mostly composed of unfossiliferous bathyal 
sediments. The Nishigawa division containing 
the Torinosu limestone is undoubtedly Upper 
Jurassic. (Kobayashi, To. Kimura, Ichikawa). 

IIIc. The marginal zone of the Yezo geosyn- 
cline. The Iwaizumi formation (10) in the 
northern Kitakami mountains is 570 m. thick and 
composed of conglomerate, sandstone, clayslate, 
schalstein and biohermic limestone containing 
the Torinosu limestone fauna. (Onuki). 

11 Id. The axial zone of the Yezo geosyncline 
in Central Hokkaido where the Sorachi forma- 
tion with the Albio-Aptian Orbitolina limestone 
in the lower part. As it is called "Schalstein 
formation" its leading components are andesitic 
and basaltic tuffs, tuffaceous sandstone, siliceous 
slate and Radiolarian chert. The inclusion of the 
Torinosu limestone warrants that a part is Upper 
Jurassic. 



If the Sorachi, Shimanto and Sambosan groups 
are excluded, the base of the Jurassic is well 
marked. On the contrary there are some passage 
beds toward the Cretaceous. 

Because the meta-orogeny of the Akiyoshi 
cycle did not cease, the Lias of the Kuruma basin 
is astonishingly thick. Subsequently the Liassic 
basins (la) were emerged and new ones (Ib) 
brought to being in Central Japan by the Hida 
disturbance. Its influence was reduced in the 
western area (Ic) where, however, the Toyora 
and Toyonishi series are separated by the dis- 
cordance of the early Oga phase. In marked 
contrast to the Toyora cycle of sedimentation, 
the facies is changeable vertically as well as 
horizontally and sometimes local discordances 
are met with in the paralic Toyonishi series. 
These aspects on the hole demonstrate the crustal 
unstability in the Oga prelude of the Sakawa 
orogeny. 




Index Map to the Jurassic Areas in Japan. 

I. Chains of basins in Akiyoshi hinterland. 

Broken line: Boundary between Sangun 
metamorphosed zone and Yamaguchi 
folded zone of Akiyoshi folded mountains, 
la. Kuruma(8), Iwamuro(4), and Yamaoku 

(3) basins. 
Ib. Tetori (4), Kuzuryu (5), Jinzu (6) and 

Furukawa (7) areas. 
Ic. Toyora (2) and Toyonishi (1) basins. 

II. Marginal depressions of Eo-Nippon Cordil- 
lera. 

Black : Eo-Nippon Cordillera. 
Ila. Shizukawa embayment of South Kita- 
kami; Shizukawa (11), Hashiura (12) 



and Mizunuma (13) areas. 
lib. Ojika embayment of South Kitakami; 
Karakuwa (14) and Ojika (15) areas. 

He. Jurassic strip of Soma (16). 
III. Yezo-Shimanto geosyncline. 

Ilia. Near-shore zone of Shimanto geosyn- 
cline; Sakawa (18) and Sakuradani 
(17) areas. 

II Ib. Off-shore zone of Shimanto geosyn- 
cline (Vertical lines). 

IIIc. Marginal zone of Yezo geosyncline; 
Iwaizumi area (10). 

Hid. Azial zone of Yezo geosyncline (Hori- 
zontal lines). 

263 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



The growth of the depressions in the southern 
Kitakami and Soma areas (II) and the increase 
in the rate of sedimentation from Lias to Malm 
indicate that the axial culmination of Eo-Nippon 
was accelerated and its embryonic folding was 
developing through the Jurassic period. The 
Torinosu series is comparatively thin, because 
the Torinosu zone (Ilia) was distant from the 
Eo-Nippon Cordillera. If the Radiolarian cherts 
in the Sichota Alins and the lower Amur valley 
are really in part Jurassic and their development 
is related to submarine volcanism, they may be 
allied to the Sorachi fades in Hokkaido (III). 

The normal marine Jurassic is extensive in the 
maritime province of USSR, but the Dogger is 
limited, probably due to the Hida emergence or 
disturbance. In the Sichota Alines the Middle 
and Upper Jurassic containing Trigonia costata 
and Myophorella imbricata is said to overly the 
Lias clino-unconformably. Because various 
inocerami occur commonly and extensively in the 
province and also in the Akiyoshi basins and the 
southern Kitakami region (I, Ila-b), their com- 
parative study is of prime importance for the 
stratigraphic correlation. 

Recently the Lias of Japan was zonated as 
shown in the table. Each basin or column bears 
its own individuality, but in Japan the Aalenian is 
more properly combined with the subjacent 
than the superjacent formation. No ammonite 
represents lower Hettangian, lower Sinemurian 
or lower Pliensbachian. Broadly speaking, 
the Liassic fauna is intimately related to those of 
the southwestern Pacific, but boreal Amaltheus 
is coexistent with the Tethyran Canavaria in the 
Domerian of the Kunuma basin. The Aalenian 
of the Mae-Sot region, West Thailand, is linked 
with that of Alaska through the southern Kita- 
kami by common occurrences of Tmetoceras. 
(Sato). 

Bajocian Stephanoceras cfr. plicatissimum from 
the Karakuwa series (lib) is one of the a few 
Middle Jurassic ammonites in Japan (Sato). 
Her Upper Jurassic fauna comprises quite a 
variety of Perisphinctids in addition to some 
oppelids and others. It is noteworthy that the 
inflow of cold water into the Kuzuryu and 
Shizukawa basins in the Callovian epoch is proven 
by the discovery of Kepplerites (Seymourites) 
(Kobayashi). 

The Liassic pelecypod fauna in Japan com- 
prises about 145 forms (or species plus varieties) 
in 54 genera, of which 37 forms in 24 genera 
occur in the Shizukawa series (1), 68 forms in 
32 genera in the Kuruma series (2) and 46 forms 

264 



in 29 genera in the Toyora series. Among them 
2 forms and 14 genera are common between 
(1) and (2), 4 forms and 11 genera between (2) 
and (3) and 0.5 form and 6 genera between (3) 
and (1) where aff. or cfr. is counted 0.5. The 
weak affinity among these faunas depends more 
on ecology and endemism than time-difference. 
While certain species in the Toyora fauna are 
almost identical with lower Liassic ones in Europe 
serveral new genera indicate strong individual- 
ities of the Shizukawa and Kuruma faunas. 
Cyrenoids common in the Shizukawa and 
Kuruma series have attracted attention of con- 
chologists because of their archaeism. They 
are, however, probably not true cyrenids, but 
marine members of the Cyprinidae (Hayami). 
The corbiculid fauna of the Tetori series may be 
the oldest non-marine one in Japan (Kobayashi 
and Suzuki). 

Some 35 Trigonian species in 11 genera are 
known from the Jurassic of Japan (Kobayashi, 
Mori and Tamura). Geratrigonia, for example, 
is a Liassic indigenous genus. Nipponitrigonia 
is another in the Jurassic and Lower Cretaceous, 
but distributed as far as the Philippines. Vau- 
gonia as a genus is cosmopolitan in the Jurassic, 
reaching its acme in Dogger, but in Japan it 
flourished more in the Lias than later. Oistotrigonia 
was considered a Cretaceous member of the 
Myophorellinae, but its progenitor appears in 
Japan already in Malm. In the southern Pacific 
on the contrary it occurs in Senonian. Thus one 
must be cautious for distant correlation by means 
of Trigonian genera. 

Many Trigonian species in Japan are limited 
to one or a few closely set areas. There are, 
however, some having wide distribution. Lino- 
trigpnia toyamai is a guide fossil of the Torinosu 
series. Myophorella obsolete* occurs in the Malm 
of the South Kitakami and in the middle Shi- 
~manto formation of Shikoku. M. orientalis 
(i.e., Trigonia formosa by Shimizu, non Lycett) 
is described from the upper Malm of the south 
Kitakami, Soma and Kuzuryu in Japan and 
reported to occur also in Ussuri. In Mindoro, 
Philippines, it is found associated with Latitri- 
gonia, Nipponitrigonia and Rutitrlgonia, the 
generic assemblage suggesting the Jurasso-Cre- 
taceous passage for the Trigonian sandstone of 
Amaga, Mindoro. Trigonia molengraffi from 
West Borneo is probably Upper Jurassic, instead 
of Cretaceous, because it is intimately related 
to Myophorella crenulata from the Malm of 
Soma (Kobayashi). 

Jurassic brachiopids from Shikoku island 
comprise 16 species in 10 genera including 



VOLUME ]2_ GEOLOGY AN^jGEOPHYSICjS 

CORRELATION OF THE LIASSIC FORMATIONS IN JAPAN 



Toyora Series (Matsumoto & Ono) 



Uh 



Hammatoceras 
Dumortieria 



Ub Haugia 

Up Pseudolioceras, Chartronia 

Ni Dactylioceras 



Hildoceras, Dactylioceras 
Nh Harpoceras, Peronoceras 

Brodceras, Protogrammoceras 

Protogrammoceras 
Murleyiceras, Harpoceras 
Ng Harpoceratoides, Brodieia 
Dactylioceras, Hildoceras 

Fontanelliceras, Arieticeras 
Nf Fuciniceras, Paltarpites 
Protogrammoceras 



Hiatus 



Upper Higashi-Nagano Beds 
Arietites 



Rhacophyllites 

Lower Higashi-Nagano Beds 

Up, b,h: Lower Utano Beds 
Nf-i : Nishi-Nakayama Beds 



Hi, a and HI, h: Lower and Upper Hosoura Beds 
Nsh, ss : Niranohama Beds 



Kuruma Series 


Shizukawa Series 


Age 




Mizukami-dani 


Hammatoceras 
Hh Hyperlioceras 


.2 

<D 




Beds 


Tmetoceras 


CS 
< 




Otaki-dani Beds 


Leioceras ? 






Crammoceratid 


HI Tmetoceras 






Hammatoceratid 


Harpoceras 










Ctf 




Shina-dani 




o 

l_* 

a 






Beds 










Hiatus 






Teradani Beds 






C3 


Amaltheus 
Canavaria 




.c 


1 

O 

Q 


(Deroceras) 
Negoya-dani 




C/3 


a 

R 


Beds 






VH 

cd 

U 


Kitamata-dani 






c 


Beds 


Ha Arnioceras 
















Jodogani 


Hi 




5 


Beds 


Nss Yebisites 


t 






Nsh 


ffi 





265 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Burmirhynchia, Kallirhynchia, Parmirhynchia, 
Zeilleria, Terebratulina and so forth. The 
Miyakodani, Naradani and Torinosu faunules 
in the table can be dated respectively as Lias, 



Dogger and Malm. They are on the whole 
related to the faunas in the Tethyan province, 
especially of the Shan State, Cutch and Attock 
districts (Tokuyama). 



Genera/Species 
Torinosu; Malm 



Naradani; Dogger 
Miyakodani; Lias 



Total (n. gen. or n.sp.) 



Rhynchonelloids 


Terebratulloids 


Total 


2/2(3) 


4(l)/5(5) 


6 (l)/8(8) 


2/2(1) 


4 (0/4(4) 


6 (l)/6(5) 


2/2 


2/2 


4/4 



The Torinosu series is in the time-range from 
Callovian to Tithonian as determined by the 
following fossils: 

1. Horioceras mitodense, Hecticoceras sp, Siga- 

loceras sp. Properisphinctes aff. bernensis 

Callovian and lower Oxfordian 

2. Lithacoceras tarodense Uppermost Oxfor- 
dian to lower Kimmeridgian 

3. Ataxioceras kurisakense, Aulacosphinctoides 
steigeri Kimmeridgian 

4. Pseudosaccocoma japonica Tithonian 

Beside these there are Pseudocydamina, Millep- 
oridium and many other warm water inhabitants 
(Hanzawa, Eguchi), showing affinities to the 
Tethyan fauna. In view of not only the deve- 
lopment of the southern members, but also the 
inclusion of the definitely northern elements, 
the Jurassic of Japan is found to be a key point 
for interprovincial correlation. 

Finally, it is noted that all marine faunas in 
Japan are so similar in the late Triassic period 
that no barrier is recognizable between the 
inner and outer side, while the Jurassic ones are 
quite different between the two sides, the facts 
showing the appearance of the Eo-Nippon 
Cordillera. Due to the development by the Sakawa 
orogeny, the difference became by far greater in 
the Cretaceous period when the non-marine red 
formation was extensively developed on the inner 
side. 



For the recent advancements in the stratigra- 
phy of the other systems, see the following 
papers : 

Fujimoto, H., 1952, The fusulinid Zones in 

the Japanese Carboniferous. Cr. 3e 

Congr. Strat. Geol. Carbon. Heerlen, 
7957, Vol. 1. 

Hayasaka, I. and Minato, M., 1952, Carbo- 
niferous Formations in the Japanese 
Islands. Ibid. Vol. 1. 

Ichikawa, K., 1956, Triassic Biochronology 
of Japan. Eight Pacif. Sci. Congr. 
Philippines, 1953, Proc. Vol. 2. 

Ikebe, N., 1956, Cenozoic Geohistory of 
Japan. Ibid. Vol. 2. 

Kobayashi, T., 1952, Late Palaeozoic and 
Triassic Palaeogeography of Eastern 
Asia and its Relation to the Floral 
Evolution. C. R. 3e Congr. Strat. 
Geol. Carbon. Heerlen, 1951, Vol. 1. 

. 9 1956, The Triassic Akiyoshi Oro- 
geny. Geotektonisches Symposium zu 
Ehren von Hans Stille. 

Matsumoto, T., et al, 1954, The Cretaceous 
System in the Japanese Islands. Japan. 
Soc. for Prom. Sci. Tokyo. 

Asano and Toriyama's papers in this publica- 
tion. 



266 



VOLUME 12 



RECENT ADVANCES IN THE CORRELATION 
NEW ZEALAND CRETACEOUS SEDIMENTS 



GEOLOGY AND GEOPHYSICS 
OF 



H. W. WELLMAN 

BP Shell and Todd Petroleum Development Limited, Gisborne, New Zealand. 



This paper summarizes the main advances in 
Cretaceous stratigraphy made in New Zealand 
since 1953. Inoceramus has been found to be 
widespread in New Zealand upper and middle 
Cretaceous sediments. Many of the species have 
short ranges and are useful for local and overseas 
correlation. The existing stratigraphy has been 
revised and several new stage divisions proposed. 
The section at Coverham Clarence Valley, 
previously considered the type for the middle 
Cretaceous, proved to be complexly deformed and 
stratigraphically misleading. New type sections 
have been proposed. The new divisions probably 
provide a substantially continuous sequence from 
the base of the Tertiary down to the Aptian or 
Neocomian. In the Raukumara Peninsula the 
Taitai Sandstone was considered to have been 
thrust over upper Cretaceous sediments for many 
miles, but the supposed upper Cretaceous sedi- 
ments are actually lower Cretaceous and probably 
older than the Taitai Sandstone, and there is no 
stratigraphic evidence for the overthrust. 

HISTORY OF RECENT STUDIES 

During the last five years many New Zealand 
Cretaceous sections have been re-examined and 
considerable stratigraphic changes made. A 
preliminary chart showing the proposed new 
divisions was published in the abstracts of the 
XX International Geological Congress (Wellman, 
1956) and full descriptions of the proposed new 
divisions are in the press. 

Correlation is mainly based on Inoceramus 
which is widely distributed and occurs in a variety 
of sediments. Ammonites are so rare as to be 
useless for local correlation. Foraminifera are 
most important in the uppermost Cretaceous. 
Four of the five Inoceramus species already 
described /. porrectus, I. pacificus, and /. aus- 
tralis, all of Woods, 1917, and /. bicorrugatus 
Marwick 1926 are widespread in New Zealand. 
/. concentricus Park, is known in New Zealand 
from Coverham in the lower Clarence Valley 
only. Ten new species have been recognized of 
which seven are widely distributed. The new 
species are being described and will be referred 



to here by the initial letter of their proposed 
specific name. 

The stratigraphic revision started on the east 
coast of the North Island where the following 
Inoceramus sequence was established in several 
sections :- 

/. australis and /. pacificus 

L sp. O 

/. bicorrugalus 

L sp. R. 

The two species that occur together at the top 
of the sequence were originally described from 
Amuri Bluff (Woods 1917) in the lower part 
of the type section of the Piripauan Stage (Thom- 
son 1917), and date the upper part of the east 
coast sections as Piripauan. The species below 
had been collected at various times from or near 
what was considered to be the type section for 
the New Zealand middle Cretaceous at Cover- 
ham in the Clarence Valley, South Island (Thom- 
son, 1919), but the succession at Coverham did 
not match that established on the east coast of 
the North Island. 

This was found (Wellman 1955) to be due to 
complex folding and faulting that had produced 
an extremely misleading section considered by 
Thomson (1919) to be stratigraphically conti- 
nuous. The true sequence at Coverham is identical 
with that established on the east coast, but with 
the addition of older fossiliferous beds with 
Inoceramus porrectus Woods, Aucellina euglypha 
Woods, Turrilites^ and Inoceramus concentricus 
Park, on which the whole section had been 
dated as Albian to Cenomanian by Woods in 1917. 
Finlay and Marwick based their Clarence Series 
on the Coverham section and considered it 
Albian in 1947. 

The Clarence Series was restricted by Wellman 
in 1955 to the older beds with the fossils described 
by Woods, and a new time-stratigraphic division 
the Raukumara Series proposed for the beds 
between the base of the Piripauan and the top of 
the restricted Clarence Series. The Raukumara 
Series is divided into three stages Arowhanan, 
Mangaotanean, and Teratan on the basis of 
Inoceramus. 

267 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRLSS 



It was found by Mr. N. de B. Hornibrook of 
the New Zealand Geological Survey (in Wellman, 
1955) that the east coast beds with /. pacificus 
contain foraminifera that more closely resemble 
those of the Raukumara Series than they do those 
that had been considered typical of the Piripauan 
through South Island correlation from Amuri 
Bluff to Waipara River. 

The importance of Foraminifera for the 
division of the uppermost Cretaceous and basal 
Tertiary had been established by Finlay on the 
east coast of the North Island (Finlay and 
Marwick, 1947), but the virtual absence of 
foraminifera from the type Piripauan had made 
it difficult for him to relate the deeper water 
foraminiferal sediments of the cast coast with the 
shelf sandstones with abundant Mollusca, on 
which the Piripauan had been based. Correla- 
tion was indirect and partly based on lithologic 
correlation. The discovery of the deeper water 
east coast sequence with /. pacificus and /. aus- 
tralis made correlation with the type Piripauan 
possible. As it was known that /. pacificus and 
/. aust rails are confined to the older part of the 
type Piripauan section at Amuri Bluff, the fora- 
miniferal fauna on which correlation with the 
Piripauan had been based evidently represents 
the younger part of the Piripauan only. Subdivi- 
sion of the Piripauan became necessary. "Piri- 
pauan" was retained as the stage name for the 
lower part with the key fossils /. australis and 
/. pacificus and "Haumurian" proposed as the 
stage name for the upper part. The type section 
at Amuri Bluff was retained as the type for the 
two stages, the boundary being taken at the bottom 
of the Black Grit of McKay (1877 p. 178) 

The difficulty of correlating stages defined on 
Mollusca with those defined on Foraminifera 
has recently caused a further modification of the 
New Zealand uppermost Cretaceous time-strati- 
graphic divisions. The Mata Series was intro- 
duced by Finlay and Marwick in 1947 to include 
the Piripauan (now Piripauan and Haumurian) 
and the younger Teurian, and Wangaloan stages. 
The type locality for the Teurian, at Te Uri 
Stream in Hawkes Bay, North Island, is part of a 
sequence that extends up from the Haumurian 
through the Teurian to include the type localities 
of the four stages of the Dannevirke Series (Pale- 
ocene and lower Eocene). These stages are 
without Mollusca and the divisions are based 
entirely on Foraminifera. The Wangaloan 
(Finlay and Marwick, 1937) is a geographically 
isolated stage based on shallow water Mollusca 
and is without Foraminifera, the type locality 
being in the South Island 20 miles south of 

268 



Dunedin. It has recently been suggested by 
Harrington and Hornibrook (1957) that the 
Wangaloan is probably the equivalent of either 
the Teurian stage or of one of the lower stages of 
the Dannevirke Series, and that it should be 
abandoned as part of the New Zealand stage 
sequence because of its poor stratigraphic defini- 
tion as compared with the continuous sequence 
of stages based on the Te Uri Stream section. 

With the additions and modifications outlined 
above, the New Zealand Cretaceous succession 
is now well established down to the base of the 
Raukumara Series, that is, down to about the 
base of the Senonian. 

The pre-Senonian succession is somewhat less 
certain. The Coverham section, although mod- 
erately fossiliferous, is too strongly deformed 
to be useful. Better sections are known from the 
east coast of the North Island, several of which 
extend down to dark massive sandstone of 
probable Aptian age and are overlain by Rauku- 
mara beds. The best section at present known is 
in the upper valley of Motu River and extends 
eastwards for one mile from Motu Falls. It has 
been made the type for three of the four stage 
divisions of the Clarence Series. 

Dark unfossiliferous sandstone at the base of 
the Motu Section can be correlated with reason- 
able certainty with sandstone 15 miles south-west 
at Koranga from which Aptian fossils were 
described by Marwick in 1939. The Koranga 
Sandstone underlies fossiliferous Clarence beds 
and overlies greywacke that unfortunately is 
unfossiliferous. The inferior position of the 
Aptian Koranga Sandstone to Clarence Series 
is thus reasonably well established, but it is 
difficult to determine the exact stratigraphic 
position of the Inoceramus concentricus bearing 
beds of Coverham on which the Covenan Stage 
is based, because /. concentricus appears to be 
absent from Koranga and Motu Falls and the 
lowest diagnostic fossils in the Motu Section 
/ sp. K -appears to be absent from Coverham. 

The pre-Clarence sequence is even less certain. 
At Coverham the Coverian Stage overlies the 
Wharfe Sandstone which in turn overlies dark 
crushed mudstone with a poorly preserved flat 
Inoceramus (L sp. W). At Pahaoa River in the 
southern part of the east coast of the North Island 
dark massive sandstone similar to that at Motu 
Falls and Koranga overlies dark crushed mud- 
stone with an Inoceramus that is poorly preserved 
but apparently identical with that below the 
Wharfe Sandstone (per. comm. Mr. J.B. Water- 
house). At Tapuwaeroa Valley in the northern 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



part of the east coast a dark massive unfossil- 
iferous sandstone named the Taitai Sandstone 
by Ongley and Macpherson in 1926 forms pro- 
minent cliffs at the top of Mt. Taitai and at the 
top of several nearby mountains. The sandstone 
is surrounded and probably underlain by dark 
crushed mudstone with a flat Inoceramus similar 
to that at Covcrham and Pahaoa River. The 
dark crushed mudstone- named Mokoiwi Mud- 
stone from Mokoiwi Stream in Tapuwaeroa 
Valley is unfortunately not present below the 
fossilifcrous sandstone at Koranga with which 
the Taitai Sandstone had been correlated by 
Finlay and Marwick (1940). The slratigraphic 
relation between the two pre-Clarence fossili- 
ferous formations the Mokoiwi Mudstone and 
the Koranga Sandstone is probably not yet 
clearly enough established to warrant their being 
used as the basis of stage divisions as was proposed 
by Wellman in 1956. The two stages were 
grouped together under the Urewera Series 
(Wellman, 1956). Dr. C.A. Fleming has since 
drawn the attention of the wntcr to the original 
use of Taitai by McKay in 1887 as a formation 
name that in terms of the present day nomen- 
clature includes both Mokoiwi Mudstone and 
Taitai Sandstone. It thus seems best to abandon 
the Urewera Series and to replace it by Taitai 
Scries, the name being used in a time-strati gra- 
phic sense for Cretaceous beds of pre-Clarence 
age, and in particular for the Koranga Sandstone, 
the Mokoiwi Mudstone, and their fossiliferous 
correlatives. 

DESCRIPTION OF STAGES 

The revised list of the stages and series for the 
Cretaceous of New Zealand, and their probable 
relation to the International Divisions, is shown 
by the table on page 271. The mapping symbols 
shown below the stage names are based on the 
initial letter of the series and stage name, and 
follow the system used by Finlay and Marwick in 
their revision of the Cretaceous and Tertiary stages 
in 1947. The symbol "U" is proposed for the 
Taitai Scries to distinguish it from the upper 
Miocene Taranaki Series. The table also shows 
the sequence of Inoceramus species, and the stages 
in which Ammonites and some of the more 
important of the other Mollusca are found. 

By far the greatest number of New Zealand 
Ammonites are from the upper Cretaceous of 
Northland and were described by Marshall in 
1926. All Marshall's specimens were found in 
loose concretions on coastal beaches, and are 
considered to have been derived from concre- 



tions in alternating sandstones and shales (Mason 
1953: 350) that are now classed as Haumurian. 
Ammonite-bearing concretions were found by 
Mason (1953) within a conglomerate of Haumu- 
rian or Teurian age near Hokianga. The Hokianga 
ammonites are evidently older than the conglom- 
erate in which they are found and it is possible 
that some of the Northland Ammonites described 
by Marshall arc derived from conglomerate and 
that some may be older than Haumurian. Only 
two of the Northland Ammonites are shown in the 
table. Concretions with Ammonites and Inocera- 
mus are known at a few places on the East Coast 
of the North Island in conglomerate of about 
the same age as that at Hokianga. The con- 
cretions contain Clarence and Raukumara as well 
as Haumurian fossils and the east coast conglom- 
erate must represent an important erosion 
interval. 

Most of the pre-Pinpauan Ammonites were 
recently identified by Mr. C. W. Wright of 
London, full descriptions being in the press. 

A brief description of the lithology and thick- 
ness of the Cretaceous stages, and of the more 
important fossils used for overseas correlation 
is given below. 

MATA SERIES (Daman to Campanian). 

The Mata Scries is now considered to contain 
three stages, the Teurian, the Haumurian, and the 
Piripauan. 

The upper Mata stage the Teurian was 
originally defined by Finlay and Marwick in 
1947 and has recently been redefined by Horni- 
brook and Harrington (1957) to include beds 
that were previously considered Wangaloan. 
It contains a high Cretaceous micro-fauna, is 
overlain by the Waipawan Stage with a Palcocene 
micro-fauna, and is considered to be Danian 
in age. As originally defined at Te Uri Stream, 
Hawkes Bay, it consists of 175 feet of dark 
calcareous siltstone; as redefined by Hornibrook 
and Harrington at Waipawa it included 250 ft 
of dark siltstone overlain by 100 ft of black silt- 
stone. The stage is widely distributed and 
occurs in all the New Zealand Cretaceous dis- 
tricts. The Teurian contains foraminifera that 
are considered to be Danian (Hornibrook and 
Harrington, p. 666). 

The type Haumurian includes the Sulphur 
Sand (500 ft) and the Black Grit (25 ft) of the 
Amuri Bluff Section. Haumurian sediments 
are widely distributed and include the Sulphur 
Sand, Whangai Shale, and Tapuwaeroa Beds 
facies that range from shelf sands to redeposited 

269 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



sediments. The shelf sands are up to 600 ft thick 
and the redeposited sediments as much as 5,000 ft 
thick. The Whangai Shale contains Maestrich- 
tian foraminifera (Hornibrook and Harriang- 
ton, 1957). The Haumurian contains the 
youngest Ammonites, Belemnites, and Inoceramus 
known in New Zealand. Some of the Ammonites 
are widely distributed Maestrichtian forms, and 
the Haumurian is considered to be Maestrichtian 
in age. 

The type Piripauan includes 400 ft of richly 
fossiliferous concretionary sandstone in the 
lower part of the Amuri Bluff Section (Woods 
1917). At most other places it is well sorted 
carbonaceous medium grained sandstone with 
few fossils except the two key species of Inocera- 
mus /. pacificus, and 7. australis. Its thickness 
ranges from 10 ft to 1 ,000 ft. Inoceramus australis 
appears to be related to /. balticus Joh. Bohm, 
that is widely distributed in the Campanian of 
Europe. 

RAUKUMARA SERIES (Santonian and Coniacian). 

The three stages of the Raukumara Series, the 
Teratan, Mangaotanean, and Arowhanan are 
exposed in sequence at their type localities at 
Mangaotane River and its tributary Te Reta 
Stream, Raukumara Peninsula. 

The Teratan the upper stage consists of 
about 2,000 ft. of massive siltstone with calcareous 
concretions that contain the key Inoceramus 
species 7. sp. N and 7. sp. O. It is overlain by 
Piripauan sandstone whith 7. pacificus and 7. 
australis. 

The Mangaotanean Stage consists of massive 
siltstone about 700 ft. thick with the key fossil 
7. bicorrugatus (Marwick). 

The Arowhanan consists of similar siltstone 
with interbedded bands of redeposited sandstone 
in its lower part. It is marked by the presence of 
the Inoceramus sp. R., an extremely large form, 
and rests conformably on the upper stage of the 
Clarence Series. 

The three Raukumara Stages are widely dis- 
tributed and occur in Northland, in the north- 
east of the South Island, and in the East Coast of 
the North Island. At Raukumara Peninsula 
the north-eastern part of the North Island east 
coast the three stages progressively change 
northwards from thin shelf deposits through 
massive siltstone to redeposited sediments at 
least 5,000 ft. thick. Macrofossils, except Inocera- 
mus, are extremely rare except in coarse shelf 
sediments at a few places and have not yet been 

270 



described. The two Inoceramus species of the 
upper stage 7. sp. N and 7. sp. O. are probably 
related to 7. lobatus and 7. lingua Goldf. 7. lingua 
is recorded by Seitz (1956) from the upper 
Santonian and lower Campanian of Germany. 
No related overseas forms are known for the 
key species of the Mangaotanean and Arowhanan 
stages. 

The ages of the three Raukumara Stages are 
largely based on their stratigraphic relations to 
the better dated stages above and below. 

CLARENCE SERIES (Turonian to Albian). 

The type section for the upper three stages of 
the Clarence Series the Ngaterian, Motuan and 
Urutawan is a continuous sequence near the 
Motu Falls in the upper Valley of Motu River 
at Raukumara Peninsula. 

The Ngaterian, the upper of the three stages, 
consists of about 2,000 ft of dark mudstone with 
numerous bands of redeposited sandstone. The 
key fossils 7. porrectus I. sp. H. and 7. sp. F. 
occur in the upper part of the stage directly below 
Arowhanan siltstone with 7. sp. R. 

The Motuan is about 1,500 ft thick and is 
lithologically similar to the Ngaterian. It con- 
tains 7. sp. I. in its upper part and 7. sp. U. and 
Aucellina euglypha in its lower part. 

The Urutawan is about 3,000 ft thick and is 
composed of compacted mudstone with thin 
bands of Inoceramus limestone. Bands of 
redeposited sandstone occur near the top. It 
contains three bands with the key fossil 7. sp. K. 

The lowest and fourth stage of the Clarence 
Series is known with certainty only at Coverham 
in the lower Clarence Valley. It consists of 
blue-grey mustone with many concretionary 
bands and contains moderately abundant 7. 
concentricus and rare Turrilites. 

The Clarence Series is known from a single 
locality in Northland and from many places in 
the east coast of the North Island and in the 
north-east of the South Island. It is more com- 
pacted than the Raukumara Series and at most 
places is thicker, more strongly deformed, and 
with fewer fossils. 

The fossils of the Clarence Series are more 
easily correlated with those outside New 
Zealand than are those of the Raukumara Series. 
At Port Awanui 7. porrectus was found in a 
derived boulder with an Otoscaphites that suggests 
correlation with the upper Turonian of England 
(Wright, in press). 7. sp. I. of the Motuan resem- 
bles the widespread lower Turonian 7. labiatus. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



The Ngaterian and upper Motuan are thus 
considered to be Turonian in age. The lower 
Motuan contains a few ammonites that suggest 
a Cenomanian age (Wright, in press). The key 



fossil of the Urutawan resembles /. crippsi Mant. 
of the English Cenomanian. The Coverian is 
considered Albian on the basis of Inoceramus 
concentricus and Tusrilites. 





ea 


Q 


Q 










^ 




CO 






OTHER FOSSILS 


Defined by foraminifer 


Lahillia 
Ostrea lapillicola 
Conchothyra parasitic 


Trigonia pseutfocaudat 
Trigonia hanetiana 




j 
1 

O 

z 


Trigonia meridiana 
Trigonia glyptica 


Aucellina sp. 
Aucellina euglypha 
Aucellina cf. gryphaeoide 




1 Aucellina cf.gryphaeoidt 


Macoyella magnata 
Aucellina aff. pavlom 
Dicranodonta sp. 
Aucellina cf. aptiensis 








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"^5 Sj 


1 








1 
* 








s 






c^> 




. .S S 


a 








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JS 




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f 


^ ,o 




JJJ 






ViMONIT 


c 
o 


es murdocl 
ceras cf. c> 
cumshewG 


it 

i 2 

fc-3 


d 

i 






li* 

?|l 


sp. 
moceras s] 
ites zeland 




circumtae 
ras sp. 






< 




Vertebrit 
Diploma 
Maorites 


Kossmatl 
Baculites 


I 






u S-s: 

HI 

<ss 


Puzosia 
Pachydes 
Wellman 




Turrilites 
IMylocei 






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S 

CO 

N 


TEURIAN 

Mt 


HAUMURIAN 

Mh 


PIRIPAUAN 
Mp 


TERATAN 
Rt 


ANGAOTANEAN 
Rm 


AROWHANAN 
Ra 


NGATERIAN 
Cn 


MOTUAN 
Cm 


URUTAWAN 
Cu 


COVERIAN 
Cc 


(KORANGA- 
SANDSTONE) 
Uk 


(MOKOIWI 
MUDSTONE) 

Urn 


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V1VW 


rovwn^nv* 


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INTERNATIO> 
DIVISIONS 


DANIAN 


MAESTRICHT1 


i i *< 

I I 1 

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H 


CENOMANIA 


ALBIAN 


APTIAN 


NEOCOMIAf 




snoaroro 3 ddn 


H3MO1 



271 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



TAITAI SERIES (Aptian and ?Neocomian). 

The Taitai Series is extremely thick and 
fossils are rare. At most places it is strongly 
compacted and highly deformed. It is repre- 
sented by two fossiliferous formations, the 
Koranga Sandstone and the Mokoiwi Mudstone. 
The Koranga Sandstone contains a moderately 
large fauna but with fragments of Inoceramus 
only. An Aptian age is suggested by Maccoyella 
magnata, and by the occurrence together of 
AuceUina and Dicronodonta (per. comm. Dr. 
C.A. Fleming). The Koranga Sandstone is a 
fairly distinctive formation composed of massive 
dark sandstone with interbedded bands of 
igneous conglomerate. Similar but unfossilife- 
rous sandstone and conglomerate that have long 
been correlated with the Koranga Sandstone are 
best described as Taitai Sandstone (Ongley and 
Macpherson, 1926), the type locality being at 
Tapuwaeroa Valley 60 miles north-east of 
Koranga. The Mokoiwi mudstone probably 
underlies the Taitai Sandstone and contains 
Inoceramus sp. W. for which no overseas correla- 
tive is known. The reported presence of Globige- 
rina makes it likely that the Mokoiwi Mudstone 
is not older than upper Neocomian. 

The Mokoiwi Mudstone is crushed and easily 
eroded and appears to be less compacted and 
younger than it actually is. It was confused by 
Ongley and Macpherson (1928) with much 
younger mudstone and grits that they named the 
Tapuwaeroa Series and which are now known to 
be part of the Haumurian Stage. A major 
thrust was postulated by Ongley (1930) to explain 
the position of the Taitai Sandstone above the 
supposedly younger mudstone. Although the 
relation of the Taitai Sandstone to the Mokoiwi 
mudstone is not definitely established there is 
no evidence for the thrust. 

The Taitai Sandstone and Mokoiwi Mudstone . 
crop out at several places on the east coast of 
the North Island. They appear to grade west- 
ward into thick undifferentiated "greywacke and 
argillite" that possibly includes the Neocomian 
and may pass down without major unconformity 
into the upper Jurassic. 

REFERENCES 

Finlay, H.J. and Marwick, J., 1937, The Wanga- 
loan and Associated Molluscan Faunas 
of Kaitangata Green Island Subdivision. 
N.Z. Geol. Surv. Pal. Bull. 15. 

Finlay, H.J. and Marwick, J., 1940, The Divisions 
of the Upper Cretaceous and Tertiary 

272 



in New Zealand. Trans. Roy. Soc. N.Z. 
70: 77-135. 

Finlay, H.J. and Marwick, J., 1947, New Divi- 
sions of the New Zealand Upper Cre- 
taceous and Tertiary. N.Z. J. Sci. 
Tech. B 28(4): 22Z-36. 

Hornibrook, N. de B. and Harrington, H.J., 1957, 
The Status of the Wangaloan Stage. 
N.Z. J. Sci. Tech. B 38 (6): 655-70. 

McKay, A., 1887, On the Geology of East 
Auckland and the Northern District of 
Hawkes Bay. N.Z. Geol. Surv. Rep. 
Geol. Explor. 1886-87, 18: 182-219. 

Marshall, P., 1924, The Upper Cretaceous 
Ammonites of New Zealand. Trans. 
N.Z. Inst. 56: 129-210. 

Marwick, J., 1926, Cretaceous Fossils from 
Waiapu Subdivision. N. Z. J. Sci. 
Tech. 8: 379-82. 

Marwick, J., 1939, Maccoyella and AuceUina 
in the Taitai Series. Trans. Roy. Soc. 
N.Z. 68 (4). 

Ongley, M., 1930, Taitai Overthrust, Raukumara 
Peninsula. N.Z. J. Sci. Tech. 11: 376-82. 

Ongley, M. and Macpherson, E.O., 1928, The 
Geology of the Waiapu Subdivision, 
Raukumara Division. N.Z. Geol. Surv. 
Bull, (n.s.) 30. 

Thomson, J.A., 1917, Diastrophic and other 
Considerations in Classification. Trans. 
Z.N.Inst.49: 337-413. 

Thomson, J.A. 1919, The Geology of the Middle 
Clarence and the Ure Valleys, East 
Maryborough, New Zealand. Trans. 
N.Z. Inst. 51 : 289-349. 

Wellman, H.W., 1955, A Revision of the Type 
Clarentian Section at Coverham, Cla- 
rence Valley, S. 35. Trans, roy. Soc. 
N.Z. 83(1): 93-1 18. 

Wellman, H.W., 1956, The Cretaceous of New 
Zealand. XX Congreso Geol. Internac., 
Mexico, 1956. Resumenes de los Traba- 
jos Presentados, 351-2. 

Woods, H., 1917, The Cretaceous Faunas of the 
North-eastern Part of the South Island 
of New Zealand. N.Z. Geol. Surv. 
Pal. Bull. 4. 

Wright, C.W. (in press), Some Cretaceous 
Ammonites from New Zealand. Trans. 
Roy. Soc. N.Z. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



A COMPARISON OF TERTIARY FLORAL DEVELOPMENT IN 
JAPAN AND WESTERN NORTH AMERICA 

RALPH W. CHANEY 

University of California, Berkeley, California, U.S.A. 

and 

YASUO SASA 

Department oj Geology and Mineralogy^ Kokkaido University, Sapporo, Japan. 



The older Tertiary floras of Japan have a more 
temperate aspect than those of western North 
America at the same latitude. Along with the 
common conifers, Metasequoia, Glyptostrobus 
and Sequoia, there is a large and varied group of 
deciduous angiosperms in such families as 
Juglandaceae, Betulaceae, Fagaceae. Ulmaceae 
and Aceraccae, whose modern members are now 
characteristic of middle latitudes in the northern 
hemisphere. This assemblage, both of the past 
and the present, is known as the Arcto-Tertiary 
Geoflora (1). By contrast the Eocene floras of 
Oregon and northern California are made up 
largely of broad-leafed evergreens in the Dille- 
niaceae, Euphorbiaceac, Lauraccae, Moraceae 
and Sabfaceae; a palm, Sabalites, is locally 
abundant, and cycads are recorded though not 
common; conifers are rare or absent. Living 
forests of similar composition are restricted to 
lower latitudes, where the climate is free from 
frost. They and their Tertiary predecessors are 
known as the Neotropical-Tertiary Geoflora in 
America, and as the Paleotropical-Tertiary Geo- 
flora in Eurasia (1). Although palms and mem- 
bers of the tropical families above listed may be 
present in the Eocene floras of Hokkaido and 
northern Honshu, as recently listed by Endo, 
Huzicka and Tanai (2) representation of the 
Paleotropical - Tertiary Geoflora in northern 
Japan is always in a minority. Only when we 
study an Eocene flora from the Takashima coal 
field of northwestern Kyushu, at the latitude of 
San Diego, California, do we find an assemblage 
which suggests subtropical climate. To the 
ferns, Sabal and Nelumbtum reported by Kry- 
shtofovich (3) may be added Glyptostrobus and 
leaves of evergreen oaks and laurels recently 
collected by Endo and the senior author, which 
suggest a forest with the same climatic require- 
ments as those from the Oregon Eocene. There 
is indicated a latitudinal zoning of vegetation 



from Hokkaido to Kyushu, similar to that on the 
western coast of North America during Early 
Tertiary time; but in America the corresponding 
forests were more than 10 degrees farther north, 
between southeastern Alaska and Oregon. Such 
differences in position of major climatic zones 
and vegetation on opposite sides of the Pacific 
are to be expected if air and water circulation 
during the Eocene was like that of today, and if 
the continents had essentially their present 
positions. This type of evidence appears to 
refute hypotheses involving continental drift or 
changes in the axis of rotation of the earth 
during later geologic time, as previously pointed 
out (4). 

Little change in generic composition is appa- 
rent between the Eocene and Oligocene floras of 
Japan as listed by Yabe and Endo (4), and more 
recently studied by the senior author (see Table 
1). This stability is in marked contrast to modi- 
fications in floristic composition which may be 
noted in western North America during this 
interval, involving a southward migration of the 
Neotropical-Tertiary Geoflora and the incoming 
from the north of the Arcto-Tertiary Geoflora. 
While the same Holarctic center must have been 
the source of this geoflora on both sides of the 
Pacific (5), its arrival in Oregon and northern 
California was delayed until the end of the 
Oligocene because of milder climate there during 
Early Tertiary time. These southward shifts of 
geofloras were in response to a general trend 
toward lower temperature which is apparent 
throughout the world during the Tertiary period. 
Their more pronounced expression in western 
America than in eastern Asia appears to have 
resulted from fundamental differences in the 
tectonic history of the two continents, as will be 
discussed below. By the end of the Oligocene, 
the vegetation of Oregon was much like that of 
Japan, as shown in Table 1 . 

273 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Table 1. 
Occurrence of Common Tertiary Genera in Japan and Western North America. 



Japan 


Oregon and northern California 


Eocene Oligocene 


Miocene 


Pliocene 


Eocene 


Oligocene 


Miocene 


Pliocene 


Aecto-Tertiary 


Genera 
















Glyptostrobus 


X 


X 


X 


X 


X 




X 




Metasequoia 


X 


X 


X 


X 




X 


X 




Taxodium 


X 


X 








X 


X 




Salix 


X 


X 


X 


X 


X 


X 


X 


X 


Juglans 


X 


X 


X 


X 




X 


X 


X 


Alnus 


X 


X 


X 


X 




X 


X 


X 


Betula 


X 


X 


X 


X 




X 


X 




Carpinus 


X 


X 


X 


X 




X 


X 


X 


Castancea 


X 


X 


X 


X 




X 


X 


X 


Fagus 


X 


X 


X 


X 




X 


X 




Quercus 


X 


X 


X 


X 


X 


X 


X 


X 


Ulmus 


X 


X 


X 


X 




X 


X 


X 


Zelkova 


X 


X 


X 


X 




X 


X 


X 


Cercidiphyllum 


X 


X 


X 


X 




X 


X 




Liquidambar 


X 




X 


X 


X 


X 


X 


X 


Platanus 


X 


X 


X 




X 


X 


X 


X 


Acer 


X 


X 


X 


X 


X 


X 


X 


X 


Paleotropical and Neotropical-Tertiary Genera 










Sabalites 


X 


X 


X 




X 








Ficus 


X 


X 


X 




X 








Magnolia 


X 


X 


X 


X 


X 


X 


X 




Cinnamomum 


X 


X 


X 


X 


X 








Meliosma 


X 


X 


X 


X 


X 








Marlea 


X 


X 


X 


X 


X 


X 







Almost the same degree of conservatism may be 
noted in the Miocene vegetation on the western 
side of the Pacific, with close generic and even 
some specific resemblance to the conifers and 
hardwoods which dominated the Eocene and 
Oligocene forests there. Close similarity in 
composition between floras of this age in Japan 
and western North America continued. By 
Pliocene time however, differences again appear 
as a result of greater climatic changes in America. 
It is not correct to indicate that the Pliocene 
floras of Japan, so fully known from the studies 
of Miki (6) and Okutsu (7) remained unchanged, 
for they lost most of their Paleotropical-Tertiary 
members, and several Arcto-Tertiary genera 
including Taxodium and Platanus became extinct. 
There is evidence of climatic fluctuations which 
temporarily restricted this forest, as was also the 
case in California. But Metasequoia and its 
typical associates continued to be common, and 
a majority of these Arcto-Tertiary trees are still 
living in Japan though Metasequoia did not 
survive the epoch. By contrast, many members 

274 



of the Arcto-Tertiary Geoflora, including Metas- 
equoia, disappeared from western North America 
at the end of the Miocene, and Pliocene forests 
were greatly restricted except along the coastal 
borders. In addition to some hardier genera of 
the Arcto-Tertiary Geoflora, there were small 
trees and shrubs of the Madro-Tertiary Geoflora 
which came in from the south and east. This 
Pliocene type of vegetation, as studied by Axelrod 
(8) 9 still characterizes wide areas covered by 
chaparral and grassland. 

Our comparison of Tertiary vegetation on 
opposite sides of the northern Pacific Basin has 
shown wide differences in composition, succes- 
sion and distribution which can best be explained 
by referring to the geologic history of the con- 
tinents involved. Assuming that North America 
had its present position on the eastern side of 
the Pacific Basin during Eocene time, it would 
be expected that the forests from California 
northward would have been more affected by 
marine climatic influences than those at the same 
latitude on the western side; their more tropical 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



character is therefore consistent with the assump- 
tion that Asia and North America have 
through the Tertiary held essentially the same 
position with reference to the Pacific Ocean that 
they hold today. Gradual emergence of North 
America since the Eocene has accentuated the 
effects of a world-wide trend toward lower 
temperature. With the southward shifting of the 
Neotropical-Tertiary Geoflora, the Arcto-Tertia- 
ry Geoflora became dominant iri Oregon at the 
end of the Oligocene. Orogeny which culminated 
in the up-building of the Cascade Range and the 
Sierra Nevada during the Miocene and Pliocene 
has brought continental climate to the Columbia 
Plateau and the Great Basin; Late Tertiary 
changes in ocean circulation, not necessarily re- 
lated to diastrophism, have shifted the rainfall 
regime from summer to winter, and have greatly 
reduced the area in which the summer-wet Arcto- 
Tertiary Geoflora can survive, resulting in a wide 
expansion of the Madro-Tertiary Geoflora which 
is well suited to a cool, dry climate. The history of 
Tertiary vegetation in North America is a record 
of progressive change on an emerging continent. 

By contrast, the post-Eocene history of eastern 
Asia has been one of submergence, as shown by 
the paleogeographic maps of Watanabe (9) and 
Otuka (10), and by the field observations of the 
junior author. Here the moderating influence of 
the sea appears to have offset the trend toward 
climatic extremes so manifest in some other 
parts of the world, for the vegetation of Japan 
changed much less during post-Eocene time 
than in western North America. A majority of 
the characteristic Arcto-Tertiary genera lived 
throughout the Tertiary in northern Japan, but 
only during the middle of the period is there 
comparable stability in the forests of Oregon 
and California. Even in the Pliocene, when 
many of their Paleotropical-Tertiary members 
disappeared, the temperate forests of Japan 
remained largely unaltered. This conservatism 
was long ago noted by Kryshtofovich (11). 

Although the major changes which charac- 
terize the Tertiary floras of North America are 
lacking in Japan, there are many detailed dif- 
ferences in floral composition which make possi- 
ble the separation of Japanese floras on the basis 
of their age. But for the reason above suggested, 
and doubtless as a result of other geographic 
causes, the living forests of Japan and adjacent 



China have retained their Tertiary aspect, and 
may be supposed to reflect the climate and other 
environmental features of the past. This region 
will continue to provide information essential 
to any sound interpretation of the history of 
plants, and to our understanding of modern 
forest distribution in the northern hemisphere. 

REFERENCES 

(1) Chaney, R.W., Miocene floras of the 

Columbia Plateau. Carnegie Inst. Wash. 
Pub. In press. 

(2) Endo, S.K. Huzi ka and T. Tanai, 1956, 

Palaeogene floras in Japan. Issued in 
mimeographed form. 

(3) Kryshtofovich, A., 1918, Two forms and a 

palm from the Tertiary of the Takashi- 
ma coal mines in the Province of Hizen. 
Jour. Geol Soc. Tokyo, 25: 1-5. 

(4) Chaney, R.W., 1940, Tertiary forests and 

continental history. Bull. Geol. Soc. 
Am. 51: 481-486. 

(5) Chaney, R.W., 1947, Tertiary centers and 

migration routes. Encl. Mon. 17: 
144-146. 

(6) Miki, S., 1941, The clay or lignite beds 

flora in Japan with special reference to 
the Pinus trifolia beds in Central 
Hondo. Jap. Jour. Bot. 11 : 237-303. 

(7) Okutsu, H., 1955, On the stratigraphy and 

paleobotany of the Cenozoic plant 
beds of the Sendai area. Sci. Repts. 
Tohoku Univ., 2nd ser., 26: 1-114. 

(8) Axelrod, D.I., 1950, Studies in Late Tertiary 

paleobotany. Carnegie Inst. Wash. Pub. 
590: 1-323/ 

(9) Watanabe, K., 1938, Tertiary palaeogeo- 

graphy of Japan. Jour. Geog. 50 (594) : 
351-372 (an abstract in English). 

(10) Otuka, Y., 1939, Tertiary crustal deforma- 

tions in Japan (with short remarks on 
Tertiary palaeogeography). Jubilee Pub. 
in Commemoration of Prof. H. Yabe's 
60th Birthday. : 481-519. 

(11) Kryshtofovich, A., 1920, A new fossil palm 

and some other plants of the Tertiary 
Japan. Jour. Geol. Soc. Tokyo, 37: 1-20. 



275 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



A COMPARISON OF THE FAUNA OF THE PORONAI FORMATION 
OF JAPAN WITH WEST AMERICAN MIDDLE TERTIARY FAUNAS 



J. WYATT DURHAM 

Museum of Paleontology, University of California, Berkeley, California, U.S.A. 

YASUO SASA 

Department of Geology and Mineralogy, Hokkaido University, Sapporo, Japan. 



Comparison of specimens of marine mollusca 
(twenty three species) from the Poronai forma- 
tion of Hokkaido, Japan, with specimens of 
West American Tertiary species shows the 
greatest similarity to be with species from the 
Blakeley formation of Washington and Poul 
Creek formation of Alaska. Over half of these 
species vary from very close to moderately close 
to the American species. Whether or not this 
relationship indicates a like age or similarity of 
depositional facies cannot be certainly deter- 
mined at present. Because the Japanese species 
show little resemblance to species of West Ameri- 
can formations younger than the Blakeley and 
the Poul Creek, it is suggested that the relation- 
ship may indicate similar age. 

The Japanese and the most similar West 
American species are: Acila piclurata (Yokoya- 
ma) and A. gettysburgensis var. alaskensis (Clark) 
from the Poul Creek formation; Yoldia lauda- 
bilis Yokoyama and Y. olympiana Clark from 
the Blakeley formation; Y. tokunagai Yokoyama 
and Y. blakeleyensis Durham from the Blakeley 



formation; Y. watasei Kanehara and Y. cheha- 
lisensis Tegland (not Arnold) from the Blakeley 
formation; Y. cf. thraciaeformis Storer and Y. cf. 
olympiana Clark of Tegland from the Blakeley 
formation; Nemocardium ezoense Takeda and 
N. griphus Keen from the Astoria formation; 
Thyasira bisecta Conrad of Takeda and T. bisecta 
Conrad from the Blakeley formation; Macoma 
asagaiensis Makiyama and M. lorenzocnsis var. 
arnoldi Tegland from the Blakeley formation 
M. sejugata (Yokoyama) and M. cf, secta Clark 
from the Poul Creek formation; Turritella poro- 
naiensis Takeda with T. porterensis from the 
Lincoln formation and T. cf. porterensis Clark 
from the Poul Creek formation (according to 
F.S. MacNeil, 1957); Neptunea ezoana Takeda 
and Ancistrolepis teglandae Weaver (= /4. clarki 
Tegland, non Meek) from the Blackeley forma- 
tion. 

No specimens of the other species of Takeda's 
1953 list of seventy species have been available 
for comparison. 



Suggested Correlation of the Middle Tertiary Formations of the Selected Areas of the North Pacific. 



Geologic 
^ ge Hokkaido 


Alaska 


Washington Oregon 


West 
American 
Standards 
(Megafossil) 


Miocene 


low. 


Kawabata frn. 
(lower) 


t? 

Yakataga fm. 
^ 


Astoria fm. 


Astoria fm. 


Temblor 






Vaqueros 


Takino-u fm. 

Momijiyama fm. 
Poronai fm. 

/x.' r**> r>* f^/ *\*> <"v ix^ f^s 

Ishikari gr. 

(upper and 
middle) 


Nye fm. 


Oligocene 


up. 


Poul Creek fm. 


Blakeley fm. 


Yaquina fm. 


Blakeley 


low. 


Kulthieth fm. 


Lincoln fm. 


Toledo fm. 

9 


Lincoln 


Keasey fm. 


Keasey 


Eocene 


up. 


Cowlitz fm. 


Tejon 




276 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



FORAMINIFERAL CORRELATION IN THE JAPANESE PALEOGENE 

KIYOSHI ASANO 

Institute of Geology and Paleontology, Tohoku University, Sendai, Japan. 



INTRODUCTION 

During the past several years, many Fpramin- 
ifera samples from the Tertiary formations of 
Japan were studied by K. Asano and S. Murata. 
The study has arrived at the point able to sum- 
marize the sequences of Foraminifera assemblages 
in the Paleogene formations of Hokkaido, 
Kyushu and the Joban coal-field, the three main 
areas of the Japanese Paleogene deposits. 

To ascertain the geographical extent to which 
Japanese Paleogene sequences here described 
can be traced, more knowledge should be accu- 
mulated, inasmuch as a little is known about 
succession of Paieogene Foraminifera assem- 
blages in the Circum-Pacific region, except the West 
Coast of North America where numbers of for- 
aminiferal zones and stages have been proposed 
to classify the Eocene and Oligocene formations. 
Nevertheless, presence of several characteristic 
elements which are common to both Japanese 
and American sequences inclines the writer to 
believe the possibility of trans-Pacific correlation 
of Paleogene formations by means of Foramini- 
fera. 

ISHIKARI AND KUSHIRO 
COAL-FIELDS, HOKKAIDO 

The Poronai shale is the typical marine Paleo- 
gene formation of the Ishikari Coal-field, 
Hokkaido. The shale unconformably overlies 
the Ishikari group which is mainly composed of 
the coal bearing formations, and includes other 
fresh, brackish or marine deposits. The Poronai 
shale predominantly consists of grey coloured, 
massive, compact mudstone from its base to top 
with a thickness of more than 1,200 m. Being 
monotonous in lithology, the formation is diffi- 
cult to subdivide by Uthologic criteria, despite 
that subdivision is needed for exploration of the 
underlying coal-measures of the Ishikari group. 
Attempts to subdivide the formation by macro- 
fossil zones have only been successful in limited 
areas; and an Oligocene age of the formation has 
been suggested by many authors chiefly upon 
molluscan evidence. 

Foraminifera are the most common fossils in the 
Poronai shale, and the writer has proposed the 



following four foraminiferal zonules in the forma- 
tion from studies of three type sections, Hobetsu, 
Ikushunbetsu and Sorachi. They are, in des- 
cending order: 

Plectofrondicularia packardi zonule 
Bulimina ezoensis zonule 
Cornuspiroides oinomikadoi zonule 
Nonion sorachiense-Ammobaculites akab- 
iraensis zonule 

The N. sorachiense - A. akabiraensis zonule 
occupies the lower part of the Poronai of the 
southern district (Hobetsu) of the Ishikari coal- 
field, and is also found in the marine members of 
the Ishikari group. 

The Cornuspiroides oinomikadoi zonule occupies 
the lower part of the Poronai of the central 
district (Miruto) of the Ishikari coal-field; and the 
Shitakara formation of the Kushiro coal-field. 

The Bulimina ezoensis, and Plectofrondicularia 
packardi zonules are developed in the upper part 
of the Poronai of the Ishikari coal-field; and the 
Charo and Nuibetsu formations of the Kushiro 
coal-field. 

It is therefore considered that the Poronai 
must have been accumulated by successive trans- 
gressions from the south to the north of the field 
from the sequence of the foraminiferal zonules. 

Plectofrondicularia packardi, and Bulimina 
ezoensis zonules may be correlated partly, if not 
completely, with the Gaviota, Tumey and Wagon- 
wheel formations of California, and with the 
Keasey and Bastendorf formations of Oregon, 
because of the occurrences of the following 
characteristic species: 

Plectofrondicularia packardi Cushman 

and Schenck 
PL packardi multilineata Cushman 

and Simonson 
PL gracilis Smith 

Bulimina schwageri Yokoyama 
Cassidulina globosa Hantken 
Hence, the geologic age of these two zonules 
is unquestionably equivalent to that of the 
Refugian stage of California, lower Oligocene. 

The Cornuspiroides oinomikadoi zonule, which 
is characterized by the larger specimens of C. 

277 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



oinomikadoi Hanzawa and Asano (attaining up 
lo 5 mm in diameter), is a good index horizon 
of the Ishikari and Kushiro coal-fields. 

The N onion sorachiense - Ammobaculites aha- 
biraensis zonule is characterized by A. Akabiraen- 
sis Asano, Nonion sorachiense Asano, Plectina 
poronaiensis Asano, and Cyclammina paciftca 
Beck. The zonule may be correlated with the 
parts of Cowlitz formation of Oregon (upper 
Eocene) from the foraminiferal evidence. 

AMAKUSA, TAKASHIMA, KARATSU, 
CHIKUHO COAL-FIELDS, KYUSHU 

Paleogene formations of Kyushu are developed 
successively from Amakusa in the south to the 
Chikuho coal-field in the north. They are, in 
descending order (after T. Nagao) : 

Ashiya group 

Otsuji group 

Sakasegawa group 

Hondo group 

Miroku group 

The Fukami and Shiratake formations of the 
Miroku group are characterized by Nummulites 
amakusaensis Yabe and Hanzawa. According 
to Hanzawa, N. amakusaensis is more primitive 
in shell structure than a Lutetian species TV. 
boninensis Hanzawa from the Ogasawara (Bonin) 
islands; therefore the Miroku group is older than 
Lutetian in age. 

The Kyoragi formation of the Hondo group 
overlies conformably the Shiratake formation of 
Miroku group, and contains, the following charac- 
teristic species: 

Globorotalia cf. wilcoxensis Cushman 

and Ponton 

Globigerina triloculinoides Plummer 
Cyclammina tani Ishizaki 
Quinqueloculina cf. imperialis Hanna and- 

Hanna 
Q. cf. weaveri Rau 

Occurrences of numbers of new species are 
also noticeable. The Globorotalia wilcoxensis zone 
has been widely known in the lower Eocene of the 
Gulf Coast of North America; and in the Middle 
East of Asia, the zone ranges from the Ypresian 
to Lutetian. Considering the planktonic nature 
of the characteristic species of this zone, the 
Kyoragi formation can be correlated with the 
Wilcox stage of the Gulf Coast. 

The overlying Sakasegawa shale, a typical 
formation of the Sakasegawa group, contains 
many characteristic Foraminifera. The following 

278 



four zonules are at present distinguished in the 
formation : 

Plectofrondicularia packardi zonule 
Plectina poronaiensis zonule 
Plectofrondicularia nogataensis zonule 
Hemicristellaria sandersi zonule 
The Plectofrondicularia packardi zonule corres- 
ponds to that of the Poronai shale, Hokkaido 
and is believed to be equivalent of the Refugian 
stage in California. 

Characteristics of the Hemicristellaria sandersi 
zonule show similarities with those of the Eocene 
Cowlitz formation of Oregon and Washington. 
Hence, it is safe to believe that the Sakasegawa 
shale ranges in time from the late Eocene to the 
early Oligocene. 

Planktonic Foraminifera are fairly common 
throughout the Sakasegawa shale, and are appa- 
rently different from those of the Kyoragi. They 
are: 

Globigerina eocenica Terquem 
Globigerina ouachitaensis sensilis Bandy 
Globigerina cf. dissimilis Cushman and 

Bermudez. 

For the Otsuji group, the Jojima Foraminifera 
faunule from the Takashima coal-field is most 
typical. In the faunule, following new species 
(MS) are common: Elphidium iojimaense, Gau~ 
dryina kishimaensis, Pseudononion kishimaense, 
Gyroidina iojimaensis, Hanzawaia sumitomoi, 
Bulimina yabei and Vaginulina karatsuensis. 

Elphidium iojimaense and Bulimina yabei are 
known to occur in the Shimokine formation of 
the Rumoi coal-field, Hokkaido, and the Shi- 
mokine is in turn correlated with the Asagai for- 
mation of the Joban coal-field by the common 
occurrences of Trochammina asagaiensis Asano 
and Elphidium yumotoense Asano. Thus, the 
lojima formation may be correlated with the 
Shimokine and the Asagai formations, the 
geologic age of the latter was once discussed by 
Asano, referring to the Zemorrian stage of Cali- 
fornia. 

The Ashiya group, the uppermost Paleogene 
of Kyushu, is subdivided in two foraminiferal 
zonules containing the Kishima faunule and the 
Sari faunule. Most of the species of the Kishima 
faunule, the lower one, extend their ranges from 
the lojima faunule and is considered to be upper 
Oligocene. But Miocene elements of Foramini- 
fera of Japan, such as Nonion pompilioides (Fichtel 
and Moll), Planulina nipponica Asano, Trocham- 
mina nobensis Asano, Nodosaria longiscata d'Or- 
bigny and Glandulina laevigata d'Ornigny first 
appear in the Sari faunule of the Ahsiya formation. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



JOBAN COAL-FIELD, 
FUKUSHIMA PREFECTURE 

As it was previously reported by Asano, the 
Asagai formation, a typical Paleogene marine 
member of the Joban Coal-field, is characterized 
by the common occurrences of Trochammina 
asagaiensis Asano, Elphidium asagaiense Asano 



and Elphidium yumotoense Asano. With the 
close relation of these Foraminifera species to 
those of the Vaqueros formation in the Simi 
Valley, California, age equivalence of the Asagai 
to the Zemorrian stage of California was inferred. 

The above statements are summarized in the 
following table. 



Foraminiferal Correlation of the Japanese Paleogene. 



Kyushu 


Fukushima 


Hokkaido 


Amakusa 


Takashima 


Karatsu 


Chikuho 


Joban 


Ishikari 


Kushiro 


Rumoi 












Poronai 
(Ishikari) 


Nuibetsu 
Charo 
(Shiakubet- 
su) 
Shitakara 
(Yubetsu) 


/**> /v r**' /*/ f^ 

Tappu 
Shimokine 

"""""' P 



Hatatsu 
^ Yukiaino 
jg Honeishi 
4g Sari 


^ Jimbara 
2 Honeishi 
4jj Norimatsu 






Kishima 


Orio 


Shirasaka 
Asagai 
(Iwaki) 


lojima 


(Kyuragi) 


(Otsuji) 
(Nogata) 




Sakasega- 
wa 


Okinoshima 


Hondo 


(Takashima) 


Miroku 



Non-marine or no Foraminifera. 
Unconformity. 



279 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



LOWER EOCENE PHOSPHAT1ZED GLOBJGERTNA OOZE FROM 
SYLVANIA GUYOT, MARSHALL ISLANDS 

EDWIN L. HAMILTON 

U.S. Navy Electronics Laboratory, San Diego, California, U.S.A. 

and 

ROBERT W. REX 

University oj California, Scripps Institution of Oceanography, La Jolla, California, U.S.A. 

(Abstract) 



The Scripps Institution of Oceanography- 
U.S. Navy Electronics Laboratory Mid-Pacific 
Expeditions of 1950 took a number of dredge 
hauls on the top of Sylvania Guyot, the seamount 
adjacent to Bikini Atoll, Marshall Islands. Syl- 
vania has a very flat top at about 705 fathoms and 
is connected to Bikini by a saddle at a depth of 
790 fathoms ; the adjacent sea floor is deeper than 
2500 fathoms. 

In three of these dredge hauls fossil Foramini- 
fera have been found in the cracks and pockets 
inside tuff breccia or altered lava boulders which 
were convered on the outside by ferromanganese 
crusts. In all of these deposits the material was 
an ancient calcareous ooze formed by the plank- 
tonic foraminiferal fauna of the time; in two 
deposits the calcareous material was almost 
completely phosphatized. 

In the dredge haul from Mid-Pacific Station 
43-A the tuff breccia contained cracks filled with 
a phosphatized fauna of earliest Eocene age 
dominated by Globorotalia velascoensis and G. 
aragonensis; the nearest faunal affinity of this 
assemblage, the oldest in the Northern Marshall 
Islands, is with similar occurring faunas from the, 
Mid-Pacific Mountains about 1000 miles to the" 
east and with faunas from the Paleocene and 



Eocene deposits of the Tampico Embayment 
region of Mexico. 

In the dredge haul from Mid-Pacific Station 
MP 43-D and MP 43-DD the fossil planktonic 
fauna was from the Miocene. The material 
from MP 43-D is correlated with the Globigeri- 
natella insueta zone of the Carribbean; the 
material is of about the same age as that found on 
Saipan. 

The new evidence from Sylvania fits well into 
that previously determined and indicates the 
probability that in Late Cretaceous or earliest 
Tertiary time Sylvania was eroded to a flat bank; 
Bikini at this time was probably a younger and 
higher feature which had been little eroded. 
Fast subsidence in Late Cretaceous or Early Ter- 
tiary left Sylvania as a relatively deeply submerged 
flat bank while Bikini was at or above the surface. 
Subsequent submergence was relatively slow so 
that a great reef grew on Bikini while planktonic 
Foraminifera were being deposited on the top of 
Sylvania. 

It may be very significant in the geologic history 
of north-central Pacific Basin that roughly the 
same events were transpiring at about the same 
time in the Bikini-Sylvania area, in the Mid-Pacific 
Mountains to the east, and at Eniwetok to the west. 



280 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



EVIDENCE OF TERTIARY IN THE ISLAND OF BANGKA 

(INDONESIA) 

GEORGE A. DE NEVE 

Department of Geology. Andalas University* Bukittinggi, Central Sumatra. 

(Abstract) 



During the author's stay in Bangka as Head 
and Chief-geologist of the Exploration Depart- 
ment of the "Bangka Tin Mines" (Perusahaan 
Negara Tambang Timah Bangka) investigations 
and screening was carried out of pre-war rock- 
material and lists of borings drilled for the 
"Bangka Tin Mines" in order to come to a re- 
valuation of ore-reserves for the Company. An 
important geological fact hitherto unpublished 
was found and it is worth to be mentioned here 
because it is for the first time that definite evidence 
of a Tertiary sediment in the Indonesian part of 
the Tin-Belt has been delivered. 

In samples of borings drilled on the righthand 
bank of the river Menduk, 1, 5 kms. south and 
0,5 km. east of the hamlet of Airpandan (West- 
coast of Bangka) pebbles of fossiliferous marly 
clay in layers of fine sand were found at a depth 



of 15 to 20 metres by the mining-engineer A. van 
der Burg in January 1939. 

Determination of the smaller foraminifera by 
the micropalaeontologist H.E. Thalmann proved 
an approximately Pliocene age and the pebbles 
are certainly not older than Late-Neogene. The 
following foraminifera were recognized: 

Rotalia conoides d'Orb. 

Spiroloculina cf. striata d'Orb. 

Triloculina rotundata d'Orb. 

Textularia cf. gibbosa d'Orb. 
The pebbles of fossiliferous marly clay were 
found in layers of fine sand containing small 
quantities of tin-ore and deposited discordant on 
the sandstone-bedrock of presumably Upper 
Triassic age. Stratigraphic correlation with 
similar deposits from Southern Sumatra is 
discussed. 



281 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



THE USE OF CALCAREOUS ALGAE IN CORRELATING CENOZOIC 
DEPOSITS OF THE WESTERN PACIFIC AREAt 

J. HARLAN JOHNSON 

U. S. Geological Survey and Colorado School of 'Mines ; Golden, Colorado, U.S.A. 



Fossil calcareous algae occur abundantly in 
many of the marine Cenozoic deposits of the 
tropical Pacific region. They are especially 
abundant in reefs and associated deposits but 
occur also in other shallow water marine sedi- 
ments. 

Mention is made of the occurrence of algae, 
"Nullipores", "Lithothamnia", and Halimeda 
in many geological reports and papers, but 
relatively few are actually described. 

During the last 10 years the author has collected 
and studied fossil and Recent calcareous algae 
from numerous islands of the western Pacific 
and has studied collections from the East Indies, 
Japan, and Hawaii. He has also studied the 
algae obtained in the deep cores drilled in the 
reefs of Funafuti, Kita-Daito-Jima, Bikini, and 
Eniwetok. These studies have given him an 
opportunity to become acquainted with algal 
floras ranging in age from Eocene to Recent and 
from a number of quite widely separated locali- 
ties. It has been found that in general the 
ancient floras of calcareous algae resembled the 
Recent ones in several respects: (1) the floras 
consist mainly of a relatively small number of 
widely distributed forms, (2) all the calcareous 
algae have belonged to the green or red groups, 
and (3) a majority of the genera have been the 
same from the Eocene to the Recent. 1 

Throughout the Cenozoic calcareous algae 
have been locally abundant, and have contributed 
considerably in building limestones and reefs. 

CALCAREOUS ALGAE 

The calcareous algae are those algae which have 
developed the ability to secrete or deposit cal- 
cium carbonate within and around the plant 
tissue. This may be accomplished in a number 
of ways: (1) lime may be secreted within and 
between the cell walls (as among the red coralline 
algae), (2) a calcification of the tissue may start 
at the outside and gradually progress inward 
until some of the older parts of the plant are well 



calcified (as in the Recent Halimeda and among 
many ancient members of the family Codiaceae), 

(3) lime may be precipitated around the plant 
or portions of it, forming a more or less complete 
mold (as with many of the Dasycladaceae), 

(4) lime may be precipitated in and around a 
plant, colony, or felt-like growth of fine algal 
threads, forming quite solid but very porous 
calcareous masses (particularly among some of 
the lower types of green and blue-green algae). 

Calcareous algae appear in the geologic record 
far back in geologic time (middle Proterozoic) 
and have been at least locally important at various 
times and places ever since. 

CLASSIFICATION OF 
CALCAREOUS ALGAE 

Algae have been separated by botanists into 
a number of major divisions or phyla on the 
basis of the color (pigmentation) of the living 
plants. Some members of four of these phyla have 
developed the ability to secrete or deposit lime. 

Table 1 shows a classification for fossil algae 
and the basic characteristics of the most important 
groups. 

Only three of these groups occur in any abun- 
dance in the Cenozoic rocks of the Western 
Pacific. These are the red Coralline algae, and 
members of two families of green algae the 
Halimeda among the Codiaceae and some of the 
Dasycladaceae. The classification of these is 
shown on Table 2, and the names of the more 
common genera are given. 

All of these algae can be useful to the geologist 
in supplying ecological data, but the crustose 
corallines are the only ones which can be used 
for correlating and dating rocks at the present 
time. The dasycladaceans have good possibilities 
and have been used in central Europe and the 
Mediterranean region. For the Pacific area we 
do not yet have sufficient data on them. Hali- 
meda probably could be used where entire loose 



t Publication authorized by the Director, U.S. Geological Survey. 

i However, the common widespread Recent genera Porolithon and Goniolithon have not been found in rocks older than 
Tertiary g. and are not abundantly represented before the Pleistocene. 

282 



segments are available. The genus is easily 
recognized in thin sections, but species can rarely 
be differentiated, hence cannot be used for dating 
rocks. 

DISTRIBUTION 

The coralline algae of the tropical Pacific form 
a small group of rather highly specialized plants. 
At a given locality they are usually represented 
by a large number of individuals belonging to a 
small number of genera and species. The com- 
mon species have a wide geographic distribution, 
extending from the Red Sea, across the Indian 
Ocean, through the East Indies and widely over 
the western Pacific, some extending over to Ha- 
waii. The greatest variety appears to occur in 
and around the East Indies. 

The fossil assemblages studied to date appear 
to belong to two quite typical groups apparently 
separated largely by latitude (and water tempera- 



VQLUME 12 GEOLOGY AND GEOPHYSICS 

ture): (1) a temperate flora from Japan and 
Okinawa (material studied mainly Pliocene to 
Recent), and (2) the tropical flora from the 
Marshalls, Mariannas, Carolines, Palau, Fiji 
and the East Indies. Taiwan and the southern 
Ryukyus are in between as far as the fossils of 
the late Tertiary and Pleistocene indicate, but 
had the tropical flora during the Eocene. 

POSSIBILITIES OF ALGAE FOR 
CORRELATION 

So far the author's work on fossil algae from 
the western Pacific has been largely identification 
and description of material from beds of known 
age (dated by Foraminifera). Collections have 
been studied from a number of widely separated 
islands. No material of Oligocene age has been 
received, and the only Pliocene specimens studied 
came from Okinawa (see Table 3). Each collec- 
tion studied has revealed some new species, but 
a pattern is beginning to appear. No Eocene 



Class 



Rhodophyta 
(red algae) 



Phaeophyta 
(brown algae) 



Chlorophyta 
(green algae) 



Cyanophyta 

(possibly 

Chlorophyta) 



Table 1. 
Classification of Fossil Algae. 



Family or order 



Characteristic Structures 



Corallinaceae 

Solenoporaceae 

Laminar idles 
and others (?) 

Codiaceae 
Dasycladaceae 

Charophyta 



Rows of closely packed cells rectangular in section. 
Spore cases or conceptacles. 



Cyanophyta 
(blue-green algae) 



Porostromata 



Spongiostromata 



Rows of closely packed cells with polygonal cross 
section. Cross partitions present though frequently 
very thin. 

Corded strands of parallel threads (as in framework 
of Archimedes Hall). Frondese types. 



Small tubes loosely arranged so as to form segmented 
stems. Tubes round in cross section and branching. 

A central stalk, preserved as a tube or bulb, sur- 
rounded by tufts of stems or branches, preserved as 
knobs or brushlike protuberances. 

Highly developed small bushy plants. Fossils usually 
consist of calcified, heavily ribbed, spherical oogonia 
and the whorled branches which bear them. 



Small tubes so loosely arranged as not to compress 
each other. No cross partitions visible. 



Cellular structure seldom preserved. The CaCO 3 
is deposited as crusts on the outside of the colony or 
cell, or between the tissues, not in the cell wall. 
Classified on the basis of growth habit and form of 
the colony. 

283 



Phylum 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 

__ _ 

Classification of Cenozoic Calcareous Algae of the Western Pacific. 

Common Genera 



Rhodophyceae 
(Red algae) 



Chlorophyceae 
(Green algae) 



Family & Subfamily 

Corallinaceae 

\-Crustose Corallines 
( Melobesieae ) 



2- Articulated Corallines 
(Corallineae) 

Codiaceae 



Dasycladaceae 



Archaeolithothamnium 

Lithothamnium 

Mesophyllum 

Lithophyllum 

Porolithon 

Goniolithon 

Lithoporella 

Melobesia 

Dermatolithon 



Corallina 
Amphiroa 
Jania 
Arthrocardia 

Halimeda 



Bornetella 
Cymapolia 
Acetabularia 



Table 3. 
Age and Geographic Distribution of Collections Studied. 



^o 
C 



a 

03 
C 



O 



c 

cd 

.& 

"S3 



. 
12 

S 



w 



* 

i 



C3 



o 



Recent 

Pleistocene 

Pliocene 

Miocene 

Oligocene 

Eocene 



x 

9 



x 

9 



species have been found in the Miocene, and only 
two questionably determined Miocene forms 
extend up into the Pleistocene. Pleistocene 
and Recent cannot be separated, and the one 
Pliocene collection studied is very similar to 
Pleistocene and Recent. 

It is interesting to note that the Eocene flora 
is surprisingly homogeneous in all the areas 
studied, and it contains a number of forms which 
are specifically identical or very closely related to 
species which have been described from the 

284 



Mediterranean Region. The composition and 
known distribution of this flora is shown graph- 
ically as Table 4. Future work probably will add 
to the area in which the flora is known to occur. 
The Miocene flora also has links with the Medi- 
terranean, but it is not so closely connected as 
the Eocene flora. Charts showing the known 
distribution of fossil species described from the 
Western Pacific will be published in the author's 
forthcoming report on the algae from the 
Eniwetok, Funafuti, and Kita-Daito-Jima cores. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Table 4. 
Geographical Distribution of Eocene Coralline Algae Found in the Western Pacific. 



Genus and Species 



A rchaeolithothamniwn 

A, cf. A. chamorrosum Johnson 

A. dalloni Lemoine 

A. cf. A. hemchandri Rao 

A. nummuliticum (Giimbel) Rothpletz 

A. oulianovi Pfender 

A. aff. A. saipanensum Johnson 

A. cf, A. sodabile Lemoine 
Lithophyllum 

L. cf. lingusticum Airoldi 
Lithothamnium 

L. cf. L. abraidi Lemoine 

L. crisputhallum Johnson 

L. kumbecrustum Johnson 

L. cf. moreti Lemoine 

L. tapachaum Johnson 
Mesophyllum 

M. robustus Johnson 

M. vaughanii (Howe) Lemoine 
Corallina 

C. prisca Johnson 






w 



ctf 
O 

C/3 



l.f 



I 



03 



Madame Lemoine's work (1939) has shown 
that the crustose coralline algae can be used in 
correlating strata in the region around the 
western Mediterranean. The studies completed 
and in progress have convinced the author that 
they have similar possibilities for use in strati- 
graphic correlation, not only in the Western 
Pacific region, but over a much more extensive 
area embracing much of southeastern Asia. 

REFERENCES 

Foslie, M.H. and Printz, H., 1929, contributions 
to a Monograph of the Lithothamnia. 
Del Kongl. Norske Vid. Selsk. Museet. 
Monograph 60 pp., 75 pi. 

Ishijima, W., 1954, Cenozoic Coralline Algae 
from the Western Pacific. Tokyo, 
Yuhodo Company, Tokyo, 87 pp., 69 p). 

Johnson, J. Harlan, 1954, An Introduction to the 
Study of Rock Building Algae and Algal 
Limestones. Colorado School of Mines 
Quart. 49 (2): 117 pp., 62 pi. (April). 



, 1954, Fossil Calcareous Algae from 

Bikini Atoll. U.S. Geol Survey Prof. 
Paper 260-M, 537-545. 

, 1957, Fossil Calcareous Algae from 

Saipan, U.S. Geol. Survey Prof. Paper 
280-E pi. 25 (in press). 

__, 1958, Fossil Calcareous Algae from 

the Eniwetok, Funafuti and Kita-Daito- 
Jima Drill Holes. U.S. Geol. Survey 
Prof. Paper 260-W (in press). 

Johnson, J. Harlan and Ferris, B.J., 1949, Tertiary 
Coralline Algae from the Dutch East 
Indies, Jour. Paleontology, 23 (2) : 
193-198, pis, 37-39, March). 
._, 1950, Tertiary and Pleistocene Coral- 
line Algae from Lau, Fiji, Bernice P. 
Bishop Museum Bulletin 201 : 27 pp. 
9 pis. 

Lemoine, Mme. P., 1939, Les Algues Calcaires 
Fossiles de L' Algerie. Mat. Carte 
Geol. de L" Algerie, Imc Series, 9: 128 
pp., 3 pis., 80 figs. 

285 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Lignac-Crutterink, L.H., 1943, Some Tertiary Assam: 1-The Corallinaceae. Proc. 

Corallinaceae of the Malaysian Archipe- Nat. UAcad. Sciences, India, 13 (5): 

lago. Verh. Geohgisch-Mijnbouwkundig 265-299. 

Genootschap voor Nederland en Kolo- Weber van Bosse, Mrs. and Foslie, M.H., 1904, 

men. Geol. Ser., 13:283-297, 2 pi. The Corallinaceae of the Siboga Expedi- 

(Dec.). tion. Siboga Exp. Mono. 61: 110pp., 

Sripada, Rao K., 1943, Fossil Algae from 16 pi., Leyden, Holland. 



286 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



A REVISION OF THE STRATIGRAPHICAL SEQUENCE OF 
THE LANGKAWI ISLANDS, FEDERATION OF MALAYAt 

C. R. JONES 

Field Mapping Division, Department of Geological Survey, Ministry of Natural Resources, Ipoh, Federation of Malaya. 



INTRODUCTION 

The Langkawi Islands lie some 20 miles off the 
coast of Perils, in northwest Malaya and were 
first visited by Mr. J.B. Scrivenor, then Director 
of the Geological Survey, F.M.S., in 1919 and 
again in 1920. In 1922 Mr. E.S. Willbourn, 
Assistant Geologist, obtained further information. 
In all approximately 6 weeks were spent on field 
investigations. Scrivenor and Willbourn pub- 
lished, in a joint paper (1923), a preliminary ac- 
count of the geology together with a sketch geo- 
logical map. 

Scrivenor was faced with the difficult task of 
plotting his data on a poorly surveyed outline of 
the islands: many of the place names were wrong- 
ly sited. Nevertheless, a relatively accurate 
sketch map indicating the distribution and struc- 
ture of the rocks was produced on the scale of 
half an inch to a mile. Most of the geological 
details were obtained from the superbly exposed 
coastal sections, but some of the inland geological 
boundaries proved to be less accurate. During 
the latter half of 1956 more detailed mapping of 
the Islands was carried out on a scale of 2.56 
inches to a mile, using a United States Army map 
prepared from aerial photographs. 

In revising the original map by Scrivenor and 
Willbourn the geology of the area has been more 
closely studied and a number of interesting fossil 
localities have been discovered. As well as the 
information that has come to light in re-mapping 
the Langkawi Islands, other material has been 
collected in 1955 and 1956 during the course of 
field-work carried out by the writer in Perlis and 
northern Kedah and as a member of the joint 
team of Thai and Malayan geologists responsible 
for the reconnaissance survey of the Thai Islands 
which lie to the north of the Langkawi Group. 
The evidence now accumulated shows that the 
conclusions of Scrivenor and Willbourn cannot 
be upheld regarding, firstly, the age assignments 
given to the sedimentary rocks and, secondly, 
some of the stratigraphical detail. Sufficient evi- 
dence has now been obtained to make a revision 



of the stratigraphy imperative. Such a reassess- 
ment will also call for a review of the probable 
evolution of the Malayan Arc and the general 
palaeogeography of the region. 

ORIGINAL INTERPRETATION 

This section discusses briefly the findings of 
Scrivenor and Willbourn, and their interpretation 
of the geology of Langkawi in the light of what 
was known at the time about the geology of other 
parts of Malaya. The main stratigraphical suc- 
cession is set out in their paper (1923, p. 339). 
Apart from an attempt to correlate them with 
beds of known age established on the mainland, 
little information is given about the age of the 
rocks. Scrivenor (1931) suggested that more 
accurate determinations could be made as the 
identification of fossil collections from Perlis 
and other parts of Malaya progressed. 

The stratigraphical sequence given by Scrivenor 
and Willbourn is as follows: 



Group A 
Youngest : 



Group B 



Group C 
Oldest: 



quartzite and shale 



5,000 feet of limestone with a 
middle series of shale and a 
little quartzite. 

5,000 feet of quartzite and shale 
with a few thin beds of siliceous 
limestone. 



Additional information given is that 'the lime- 
stone of group B is very clearly distinguished 
from the quartzite and shale of A and C but 
no unconformity has been noted between the 
three groups .... B is conformable to C and some 
evidence has been seen that A is conformable 
toB'. 

This succession has been confirmed except for 
the quartzite and shale formation (Group A) 
said to be lying conformably above the limestone 
group. It has now been established that the beds 



t Published by permission of the Director Geological Survey with the authority of the Minister of Natural Resources. 
Government copyright is reserved. 

287 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



at Tanjong Timun, and on Pulau Tebuyi, Pulau 
Tuba, and nearby islands which on Scrivenor and 
Willbourn's map appear as Triassic, are, in fact, 
a southwesterly continuation of a formation of 
shale, phyllite, and quartzite interbedded with 
the main limestone on Pulau Timun and extend- 
ing from Tanjong Timun to the north coast of 
that island. With the removal of Scrivenor's 
group A the revised sequence, using carefully 
measured, selected sections, can be summarized 
briefly as follows : 



Younger: ! 

Setul Forma- j 

tion* I 



7,500 feet or more of massively 
bedded limestone and marble. 
At least two thin lenses of quart- 
zite and shale occupy some 600 
feet of the upper part of the 
sequence. 



Older: j 

Machinchang j 

Formation* | 

* New name 



4,300 feet or more of well-bedded 
guartzite, siltstone, and shale. 



The accompanying map (Fig. 1) shows the dis- 
tribution of these rock types, while the diagram- 
matic section (Fig. 2) shows the general structure 
of the islands. The lower quartzite and shale 
occupy in general the western half of the islands 
and dip to the east at gentle angle under the 
limestone ; the limestone forms the rugged tracts 
of land in the eastern part of the group. The 
sediments are disturbed and metamorphosed by 
a number of granite bosses on Pulau Langkawi, 
Pulau Dayang Bunting, and Pulau Tuba. When 
comparing the revised map with the old it will be 
noticed that, adjoining the limestone exposures 
near the south point of Pulau Dayang Bunting, 
Scrivenor and Willbourn mapped an isolated area 
of quatzite and shale, an extension of which 
forms the little island of Pulau Batang a mile 
off-shore. In view of the lithology and structure 
of these beds they are now believed to belong to " 
the thick lower quartzite and shale sequence. 
Their presence so far to the east of the main 
outcrop is explained by an anticlinal flexure 
affecting the rocks at this point. 

Considering again Scrivenor and Willbourn's 
original succession, it is instructive to trace the 
evidence that led to the age allocations given to 
the groups A, B, and C. The only fossils recorded 
during the early investigations were found in the 
quartzite and sha^ of group C, and in the lime- 
stone lying immediately over the passage beds 
between B and C. The quartzite and shale in 
places showed some obscure markings which were 
thought to represent the casts of worm burrows. 
288 



Univalve molluscan shells, bryozoans and other 
remains were noted on Pulau Jong (Pulau Kora), 
and crinoid stems were seen on Pulau Singha 
Kechil. No collection was made for purposes of 
identification on account of the relatively poor 
state of preservation of the specimens. Scrivenor 
and Willbourn wrote : 

'Although the limestone is almost certainly 
Carboniferous, judging from the age of the 
limestone on the mainland not very far 
removed, and although the fossils found do 
not afford evidence against this view there 
seems little prospect of obtaining a large fauna 
from these rocks. 

There can be little or no doubt that the lime- 
stone is part of the Carboniferous Limestone 
Formation that is found in Sumatra, the Malay 
Peninsula, Indo-China and Burma. 

'The shale and quartzite underlying the lime- 
stone conformably may be equivalent to the 
sandy lower beds of the Middle Carboniferous 
of Eastern Yunnan, where this period began 
with shallow water conditions. There is no 
evidence that they are older than Carboniferous 
(Devonian). 

The shale and quartzite overlying the lime- 
stone conformably is also a shallow water phase 
of the Carboniferous. On the mainland chert 
is found with quartzite above limestone and in 
younger strata still (Triassic to Jurassic).' 

In 1926 Willbourn published an account of the 
geology of Kedah and Perlis. In Perlis he 
recognized a limestone with a thick sequence of 
quartzite and shale lying conformably under it. 
The limestone here and on Langkawi was 
regarded as equivalent, the underlying quartzite 
and shale in Perlis being correlated with the rocks 
of group C on Langkawi. Fossil remains were 
found in the passage beds between quartzite and 
limestone on the Perlis-Thailand Frontier near 
Bukit Mata Ayer. A collection was described 
by R.B. Newton (1926) and the assemblage found 
to include : 

Fusulina cf. granum-avenae (Roemer) 

Doliolina cf. lepida (Schwager) 

Myropora ( ?) 

Chaetetes sp. 

Stenopora sp. 

A Cyathophylloid coral 

Cyathocrinus 

Fenestella cf. retiformis (Schlotheim) 

Schizodus sp. 

Pleurophorus sp. 



VOLUME 12 



P. TERUTAU 




SETUL 
FORMATION: 

MACHINCHANG 
FORMATION: 



GEOLOGY AND GEOPHYSICS 

LEGEND 



Alluvium 
Granite 

Ordovician-Silurian limestone with 
bands of shale and quartzite 

Upper Cambrian 
quartzite and shale 



SELAT CHIN CHIN 



P. Langgon 




Scale in Miles 6 

Fig. 1. Sketch map illustrating the revised geology of the Langkawi Islands. 



289 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Machinchang Hills 



Ayer Hangat 



P. Langgon 




WEST 



EAST 



P.Singa Besar 



P. Dayang 
Bunting 



P. Tuba 




S.W. 



N.E. 



LEGEND 



SETUL 
FORMATION: 

MACHINCHANG 
FORMATION: 




Granite 

Ordovktan-Siiurian limestone with 
bands of shale and quartzite 

Upper Cambrian 
quartzite and shale 



Fig. 2. Diagrammatic sections across the Langkawi Islands illustrating the structure. 



Due to the abundance of Fusulina the age was 
put at late Carboniferous or Permo-Carboniferous 
(Ouralian). Small lamellibranch valves were 
also found in shale near Kuala Nerang in Kedah. 
These were described by Newton (1925) as 
Halobia and given a Triassic age. It was therefore 
concluded that a quartzite and shale formation 
overlay as well as underlay the limestone, and 
that the upper formation extended into the 
Triassic. 

Scrivenor (1931) summarized the picture in his 
'Geology of Malaya*. He considered further 
evidence arising from the discovery of fossiliferous 
silty beds outcropping near Phattalung in Thai- 

290 



land. These beds bear some resemblance to the 
sediments underlying the limestone in Perlis and 
in fact would appear to represent a northerly 
continuation along the strike of the Perlis beds. 
Cowper-Reed (1920) described the fauna and 
lists the following fossils: 

Pronorites aff. cyclolobus (Phill) 
Pleurotomaria aff. conica (Phill) 
Euomphalus cf. subcircularis (Mansuy) 
Helminthochiton cf. priscus (Munster) 
Parallelodon aff. corrugatus (De Kon) 
Edmondia sp. 

Posidonomya Becheri var. siamensis 
(Bronn Sp. nov.) 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Pseudomusium cf . pratense (Von Koenen) 
Aviculopecten cf. denistria (Sandb) 
Athyris subtilita (Hall) 
Camarophoria 

Productus concentricus (Sarres-Kays) 
Productus laevipunctatus (Sarres) 
Chonetes rectispina (Von Kuenen) 
Chonetes buchiana (De Kon) 
Proetus cf. coddonensis (Woods) 
Phillipsia aff. silesiaca (Scupin) 
Cladochonus michelini (Edw. & Haime) 
It was concluded that the fauna was closely 
related to the Culm Fauna (Lower Carboniferous) 
of Europe to the extent that some of the species 
seemed identical or closely comparable with 
types occurring in Southwest England. The 
sequence at Langkawi was therefore regarded as:- 

Group A Quartzite and shale : age 

Trias. 
Group B Limestone: age Permo- 

Carboniferous. 
Group C Quartzite and shale: age 

Carboniferous. 

REASSESSMENT 

It became necessary to review the early work 
of correlation when the existence of two limestone 
formations of different ages in Perlis was recog- 
nized. Detailed investigations in that state by 
the writer in 1955 and 1956 showed two widely 
separated limestone formations divided by a 
sequence of quartzite, siltstone, and mudstone. 
The upper one of these is the limestone established 
as Permo-Carboniferous by Willbourn; but it is 
only the lower and much older formation which 
is represented in Langkawi. It is a remarkable 
coincidence that both limestone formations are 
underlain conformably by closely similar se- 
quences of arenaceous and argillaceous deposits. 
Fossil collections made in Perlis, Langkawi, and 
on some Thai Islands to the north of the Langkawi 
group, have shown that the lower limestone is, 
in fact, of general Ordovician age extending in 
time probably as late as Middle Silurian. The 
underlying quartzite and shale of western Lang- 
kawi represent deposition which took place late 
in the Cambrian period. 

The older limestone of western Perlis extends 
north into Thailand, and one of the few fossils 
which so far has been identified from this series, 
is an Orthoceratid-like cephalopod from Thung 
Song. It has been recognized as belonging to the 
genus Armenoceras of Middle Ordovician age by 
G.A. Cooper of the Smithsonian Institute. 



ORDOVICIAN AND SILURIAN LINESTONE ON LANG- 
KAWI (SETUL FORMATION) 

The limestone on Langkawi has yielded a 
plentiful and varied suite of often well-preserved 
organisms. On the islands of Pulau Langgon 
and Palau Tanjong Tembus Dendang, along the 
northwest and adjoining stretches of the coast, 
the limestone cliffs are continually being attacked 
by the sea, and this wave action has often etched 
the less resistant calcareous matrix surrounding 
the purer crystalline material which replaces the 
organisms and has revealed beautifully preserved 
specimens. The fossiliferous horizons are 
restricted and indeed great thicknesses of rock 
are barren of remains. Southwards towards 
Pulau Timun fossils become more rare. Here 
closer folding and proximity to granite intrusion 
have transformed the limestone into a soft and 
sometimes sugary marble. Distorted fossil re- 
mains can occasionally be recognized on the 
roofs of sea-caves, while, at intervals along the 
east coast of Pulau Dayang Bunting, marble 
formations carrying fibrous-looking diopside and 
tremolite also show bodies with indistinct outlines 
which can only be interpreted as the remnants 
of organic structures. The limestone lying imme- 
diately above the lower quartzite and shale on 
Pulau Singha Besar, on Pulau Singha Kechil, 
and on the nearby island stack of Pulau Jong, is 
dark and finely crystalline; it frequently yields 
moderately preserved remains. 

A large selection of the limestone fauna is at 
present under identification and should, after 
detailed inspection, provide a long list of Ordo- 
vician and probably Silurian fossils. The com- 
monest organism in the northeast Langkawi 
Islands around Pulau Tanjong Tembus Dendang 
and, in fact, throughout most of the limestone 
succession, is a plani-spiralled gastropod varying 
from a minute size to as large as 3 or 4 inches in 
diameter. There appear to be several different 
varieties of this creature depending on shell orna- 
mentation and structure. Long, helicoidally- 
spiralled gastropods are also common on Pulau 
Langgon and these are well seen in association 
with horn-shaped, coral-like structures on the 
craggy southern tip of the island. Brachiopods 
of varying genera and two or three different types 
of primitive, orthoconic cephalopods, one of 
which is probably the Armenoceras already iden- 
tified from the limestone at Thung Song, occur in 
profusion at certain points. A preliminary report 
on the brachiopods by the British Museum names 
the following organisms : 

291 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 




Fig. 3. Fragmentary Saukid Trilobites from the late Upper Cambrian Quartzites of Pulau Terutau. 



A strophomenoid 
Schizophoria sp. 
An orthid 

These are said to represent a general Ordovician 
or Silurian age. The discoid gastropods seem 
to be the forms which most strongly resist the 
forces of metamorphism and usually it is only 
the distorted remains of these creatures which 
can be seen in the Pulau Timun region. Bryo- 
zoans, crinoid ossicles and brachiopods appear 
to be the commonest kind of organisms in the 
lowest horizons of the limestone around Pulau 

292 



Singha Besar. Other fossils collected from the 
limestone of Langkawi are of a problematical 
nature and possibly belong to the phylum Porifera 
and others to the class Stromatoporoidea of the 
Coelenterata. 

ORDOVICIAN AND SILURIAN ARGILLACEOUS AND 
ARENACEOUS BEDS ON LANGKAWI (SETUL FORMA- 
TION) 

It is within the sandy and muddy phases which 
spanned the intervals between the main stages 
of calcareous deposition that the most inter- 
esting fossils and most important time indices 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



appear. Black flagstone occurs interbedded with 
dark, fine-grained, and thinly-bedded siliceous 
material represent the non-calcareous phase of 
deposition on Pulau Tanjpng Tembus Dendang 
in the northeast Langkawi Islands. These beds 
occupy a low saddle between hills of limestone 
and reach some 200 feet in thickness. Super- 
ficially they appear to have a complicated rela- 
tionship with the limestone that lies above them 
to the north and below them to the south of the 
island: the limestone is thickly bedded and dips 
constantly at a gentle angle to the northeast; in 
contrast the flaggy and cherty beds are tightly 
folded into a series of sharp anticlines and syn- 
clines. However, close examination shows that 
the sequence is wholly conformable, the zone of 
folding probably arising by virtue of non- 
competence of the closely bedded non-calcareous 
deposits between the more competent limestone. 
The flagstone on the east shore near the bottom 
of the sequence has yielded numerous biserial 
and other graptolites. Although the material 
is in a comparatively poor state of preservation, 
some very useful information has been obtained 
from an examination of the fauna. A represen- 
tative collection has been inspected by Dr. H.W. 
Ball of the British Museum in co-operation with 
Dr. I. Strachan of Birmingham University and 
Professor O.M.B. Bulman of the Sedgwick 
Museum, Cambridge. The following organisms 
are listed: 

A diplograptid 
Climacograptus sp. 
Climacograptus cf. rectangularis 
Monograptus 2 spp. 

Dr. Ball in his report comments that although 
the material is poorly preserved the assemblage 
indicates at least a Lower Silurian (Llandovery) 
age. The diplograptid in the opinion of Professor 
Bulman is either Glyptograptus or an Orthograp- 
tus of calcaratus type. He adds that the Glyp- 
tograptus which has rather an Ordovician 'look' 
about it is probably a new species; nothing in 
the Lower Silurian being comparable with it. 
Of the two species of Monograptus one has a 
small curved rhabdosome while the other, ac- 
cording to Professor Bulman, has long slender 
stipes and may be something in the nature of 
concinnus or regularis. 

In late 1956 further graptolite -bearing strata 
were discovered on Pulau Langgon about a mile 
and a half to the west of the Pulau Tanjong 
Tembus Dendang locality. Pulau Langgon is 
composed mainly of limestone, but the section 
exposed along the west coast reveals two shaly 



and sandy bands in the limestone sequence. The 
lower band, possibly 200 feet thick, is composed 
of closely bedded black brittle shaly material. 
Graptolites occur, often profusely, along lamina- 
tion planes and appear to be similar to those on 
Pulau Tanjong Tembus Dendang so that the two 
horizons are possibly equivalent. Fortunately, 
the Langgon specimens are better preserved than 
the others. Dr. Ball has provided the following 
list of genera: 

Climacograptus spp. 
Orthograptus sp. 

He adds that the material is again top poorly 
preserved to allow specific identification, and 
both the genera recorded range from Middle 
Ordovician to Lower Silurian. That this horizon 
is indeed Lower Silurian is proved by the presence 
of a further thickness of shaly beds with subsi- 
diary quartzite lying conformably above and 
separated from it by possibly 200 ft. of grey lime- 
stone. The colours of these upper beds are dis- 
tinct from the lower shaly band in that they are 
generally buff, light-grey, brown or red. One 
horizon appearing about the middle of the suc- 
cession has yielded a single but well-preserved 
monograptid identified by Drs. Ball and Strachan 
as M . clingani from the Middle Llandovery. The 
specimen was found in association with abundant 
casts of small, triangular-shaped scaphopods 
determined as cf. conularids. The age of these 
two argillaceous bands is therefore fixed with 
some precision as Lower to Middle Llandovery. 
The big thickness of limestone overlying these 
beds and forming the northern tip of Pulau 
Langgon must therefore extend well into the 
Silurian. 

The discovery of graptolites on Langkawi is of 
considerable interest since these organisms have 
not been recorded previously from this part of the 
world. The nearest other known locality to 
Malaya is in the northern Shan States of Burma 
where a suite of Llandovery graptolites has been 
mentioned by Chhibber (1934). The Burmese 
locality lies approximately 1,300 miles north of 
Langkawi. 

Bands of argillaceous and arenaceous rocks 
occurring interbedded with the limestone are met 
with again on Pulau Timun, Pulau Tebuyi, Pulau 
Tuba, and the group of six small islands lying to 
the east and southeast of Tanjong Peluru on Pulau 
Tuba. The rocks are usually in the form of 
phyllite, slate, and hard metaquartzite, their 
metamorphism being due to the effects of folding 
and the nearby granite intrusion. Although a 
careful search has been made in the less altered 

293 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



sediments no organisms have been found, and it 
is probable that, even if they had been present 
originally, they would have been destroyed by 
diastrophism. 

The age of the base of the limestone has not so 
far been ascertained, but the few fossils which 
have been collected from the rocks lying just 
above the passage beds on Pulau Singha Besar, 
and from rocks slightly higher up in the succes- 
sion on Pulau Jong, should give some indication 
when the main change from detrital to calcareous 
deposition took place. 

CAMBRIAN QUARTZITE AND SHALE ON LANGKAWI 
(MACHINCHANG FORMATION) 

Passing down into the underlying thick se- 
quence of quartzite, siltstone, flaggy rocks, and 
shale, the passage beds are conspicuous by their 
lack of preserved organic matter. The flaggy 



beds and siltstone forming the shore of Pulau 
Singha Kechil often show indistinct fucoidal 
impressions. Similar markings can frequently 
be seen on the shores of islands formed of rocks 
from the higher parts of the succession both in 
the southwest Langkawi Islands and on the 
north shore of Pulau Langkawi near Pulau Jemu- 
rok where, again, these beds can be seen passing 
up into the limestone. In addition to fucoids 
other material collected from these rocks include 
a cylindrical organism resembling a crinoid stem 
from Pulau Lallang and some small, poorly 
preserved brachiopod casts from Pulau Singha 
Besar and Pulau Jemurok. These latter remains 
have been examined and described by the British 
Museum as of Linguloid form but with a median 
ridge on the internal cast running from the umbo 
to the anterior of the shell. Although distinctive, 
these structures do not resemble any known form 
and they are thought to represent Inarticulate 







Fig. 4. Discoid Gastropods and a Cephalopod from the Ordovician Limestone of Langkawi. 



294 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



Brachiopods or primitive Terebratulids of a 
general Palaeozoic age. Fucoid markings similar 
to those on Langkawi have been described by 
Thai Geologists (1953) from shaly rocks exposed 
on Phuket Island some 100 miles to the northwest 
of Langkawi. Such markings have tentatively 
been referred to the genus Eophyton with a sug- 
gested Cambrian age. 

The massive quartzite and shale culminate in 
an anticline to form the rugged Machinchang 
Hills of west Pulau Langkawi, and the strike of 
these beds can be followed northwards over Selat 
Chinchin to the Thai island of Pulau Terutau 
about 4 miles from Langkawi. There the quart- 
zite is predominant; it is softer and coarser, and 
shows well-developed cross-bedding features 
indicating a shallow environment of deposition. 
The sandy beds can be seen passing up into lime- 
stone on the south and east shores of Pulau 
Terutau as on Langkawi. At two localities on 
West Terutau speckled red and yellow, thickly 
bedded sandstone yielded an abundance of quite 
well-preserved, though very fragmentary trilobites 
and associated brachiopod casts. On the 
southern coastal section some passage beds rich 
in a similar suite of remains were also found. 
Professor Teiichi Kobayashi of the Geological 
Institute, University of Tokyo has made an exami- 
nation of the fauna at the request of the Royal 
Thai Department of Mines. He names the 
following list of organisms: 

Apheoorthis (?) Sp. 
Brachiopod gen. et sp. indt. 
Pagodia thaiensis Kobayashi, sp. nov. 
'Eosaukia* buravasi Kobayshi, sp. nov. 
Coosia-likQ cranidium, gen. et sp. indt. 
3 kinds of free cheek, gen. et sp. indt. 
2 kinds of pygidia, gen. et sp. indt. 

Due to the fragmentary nature of the remains 
Professor Kobayashi remarks that most of the 
forms are not suitable for accurate taxonomy, 
but the three trilobites and the brachiopod to 
which names have been applied prove that the 
beds are of Upper Cambrian age. The presence 
of Saukid trilobites permits a still further nar- 
rowing of the limits to the late Upper Cambrian, 
since with the sole exception of one Eosaukid 
from Kueichou, Saukids are all late Upper Cam- 
brian. A report on the material from the same 
localities by the British Museum mentions that 
the brachiopods include forms similar to Eoorthis 
and Billingsella. With this information a reliable 
date can now be inferred for the lower formation 



of sediments on Langkawi. The bottom of the 
succession does not appear and the lowest beds 
exposed are probably those forming the southern 
point of Pulau Singha Besar. No fossils have 
been found there, and similarly the fauna from 
Terutau is more or less restricted to the upper 
parts of the exposed sequence; consequently it 
is not known whether the beds are entirely of late 
Upper Cambrian age or whether the lower parts 
of the succession include earlier parts of the 
Cambrian. However, on lithological and struc- 
tural grounds the sediments appear to have ac- 
cumulated very rapidly, so that the age defined 
by the Terutau fauna probably covers the whole 
of the exposed sequence. 

CARBONIFEROUS QUARTZITE AND SHALE EAST OF 
LANGKAWI 

Before concluding it is of interest to note that 
an assemblage of Carboniferous fossils was col- 
lected from Pulau Panjang, a Thai island lying 
between Langkawi and the mainland. The fos- 
siliferous strata are exposed on the shore and 
include brown and grey shale, mudstone, and 
quartzite. They occupy a position in a synclinal 
trough trending north-south between the limestone 
of Langkawi and the Setul Boundary Range of 
Perlis. Dark-grey siltstone is present on the 
island of Pulau Tengah to the west of Pulau 
Terutau and the Langkawi Group and appears to 
occupy a corresponding position to the Pulau 
Panjang beds in a syncline on the west side of the 
Machinchang anticline. These beds have pro- 
vided an interesting fauna determined by the 
British Museum as: 

cf. Marginirugus 

A spiriferid 

Dielasma sp. 

Worthenia aff. orientalis (Roemer) 

The age is considered as probably Carboniferous. 
The report adds that the spiriferid is a member 
of the subfamily Reticularinae and is reminis- 
cent of both Reticularia and Phricodothyris. 
The productid is comparable to productellids 
and is possibly a new genus. Scrivenor was 
therefore correct in placing a quartzite and shale 
formation on top of the limestone. The presence 
of these beds on the Langkawi group proper can- 
not be confirmed, but it is probable that they 
form the sea-floor at no great distance to the east 
of the islands. Their age is not Triassic but 
Carboniferous and they are equivalent to the beds 
underlying the upper limestone of Perlis. 

295 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



REVISED STRATIGRAPHICAL TABLE FOR LANGKAWI 

The revised form of the stratigraphical table 
representing the generalized sequence of the sedi- 
mentary rocks of Langkawi can now be sum- 
marized as follows : 



Formation 



Setul 
Formation 



Age 



Ordovician 



extending 
into the 
Middle 
Silurian or 
even later 



Description 



7,500 feet plus of mas- 
sively bedded limestone 
and marble. The rock 
is richly fossiliferous at 
certain levels, the fau- 
na being an assem- 
blage of Ordovician 
and Silurian organisms 
including the cepha- 
jlopod Armenoceras, 
I discoidally and heli- 
icoidally-spiralled 
gastropods, corals, 
brachiopods, and bry- 
ozoans. The forma- 
tion can be divided in- 
to two main calcar- 
eous phases separated 
by small thicknesses of 
shale and quartzite. A 
lower flaggy band has 
yielded Climacograp- 
tus in association 
with Monograptus in- 
dicating a lower Silu- 
I rian (Llandovery) age. 
! An upper shaly band 
i contains Monograp- 
\ tus clingani of Middle 
Llandovery age: this 
is capped by a further 
big thickness of lime- 
stone. 



Machin- 

chang 

Formation 



Late 

Upper 

Cambrian 



4,500 feet or more of 
well-bedded quartzite, 
siltstone, shale and 
flaggy rocks showing 
little variation in their 
development. A shal- 
low-water formation 
containing few fossils 
| on Langkawi, but with 
j Eosaukids and other 
I related trilobites oc- 
curring in association 
I with primitive Orthids 
i on Pulau Terutau. 



CORRELATION OF THE LANGKAWI 

SEQUENCE WITH THE LOWER 

PALAEOZOIC OF NEIGHBOURING 

COUNTRIES AND ITS IMPLICATIONS 

ON PALAEOGEOGRAPHICAL 

RECONSTRUCTION 

With the establishment of Cambrian, Ordovi- 
cian, and Silurian strata in Malaya it becomes 
necessary to discuss the relationship of these 
beds with deposits in neighbouring countries 
which are known to contain definite Lower Palae- 
ozoic fossils. Previous work has necessarily had 
to commence with the Lower Carboniferous or 
late Devonian which, until now, represented the 
oldest known period to which the rocks of Malaya 
were thought to belong. Scrivenor in an appen- 
dix in Chhibber (1934) remarks on the conspic- 
uous gap then apparently existing between the 
stratigraphical records of Malaya and Burma. 
The absence of any beds older than carboniferous 
was explained by the presence of land in Malaya 
during those times, with the consequence that no 
record remained. 

Brief descriptions follow regarding the deposits 
of Lower Palaeozoic age which to date have been 
described in the countries adjacent to and in close 
proximity to Malaya. First though, with regard 
to Malaya, it should be noted that no Lower 
Palaeozoic deposits apart from the Langkawi 
occurrences have so far been discovered, and it 
seems true to say that the possibility of doing so 
in the future is remote. 

INDONESIA 

Van Bemmelen (1949) has dealt with the geo- 
logical record of the East Indies in some detail. 
The oldest known sediments which have been 
conclusively dated come from the Snow Mountain 
Range of New Guinea where limestone boulders 
have yielded Halysites wallichii Reed proving an 
Upper Silurian age. It is certain though that 
these beds are related to the circum-Australia 
mountain system and not to the Himalaya-Penin- 
sula belt. 

The oldest known rocks of the Sunda region 
are of Lower Devonian age. The Danau forma- 
tion of east-central Borneo has yielded Clathro- 
diction and Heliolites. 

THAILAND 

Until very recently only sparse geological 
information has been forthcoming from Thailand. 
In a publication by the Royal Thai Department 



296 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



of Mines, Brown, Buravas, and others (1953) give 
a short summary of the stratigraphy of the coun- 
try. It appears that the Lower Palaeozoic is well 
represented in the Peninsula. The chronological 
column starts with a sequence of disputable 
Cambrian strata the Phuket Series of the western 
coast and associated islands. The presence of 
the problematical organism Eophyton in slates 
from Phuket Island prompted the remark 'In the 
absence of other fossils a Cambrian age cannot 
be contradicted'. Recent work by the joint Thai- 
Malayan team has shown that the Phuket Series 
may well be the northerly extension of the Upper 
Cambrian beds of Pulau Terutau, so that the 
previous temporary assignment is probably 
correct. However, the proof is not yet conclusive 
and one -difficulty which remains to be overcome 
is that the Phuket Series in several places has been 
traced up to the Burmese frontier, where the 
equivalent beds on the further side of the border 
are the Mergui Series of doubtful age, but re- 
garded as probably Carboniferous. 

The Ordovician limestone of Perlis passes into 
Thailand as the Thung Song Series, which extends 
north in a broken chain of rugged hills and passes 
out into the Gulf of Siam near Surat on the east 
coast. The beds have not been definitely recog- 
nized beyond that point. 

The Kanchanaburi Series of Thailand is an ex- 
tensively out-cropping sequence of shale and 
quartzite running north from the Malayan border 
in Perlis through Peninsula Thailand to the north- 
west tip of the country. Jt includes beds of Silu- 
rian to Carboniferous age, although breaks in 
deposition possibly occur. On the island of 
Ko Lanta Yai, south east of Krabi, it is seen lying 
over the Thung Song limestone. Pteropods 
similar to Tentaculites elegans Barrande have been 
recovered from shale near Kanchanaburi town 
and suggest a Silurian age. No Devonian fossils 
have been found up to the present time, but the 
Series extends into the Carboniferous, the 
Phattalung fossils already referred to on page 4 
coming from slate and shale of this Series. 

BURMA 

The Lower Palaeozoic is quite well represented 
in Burma and is described by Chhibber (1934). 
No indisputable Cambrian sediments have been 
mapped, but the extensive Mergui Series of 
Tenasserim has been favoured from time to time 
with a Cambrian assignment, although it is now 
generally regarded as Carboniferous (see pp. 
184-186). From a palaeogeographical point of 
view it seems very likely that Cambrian rocks 
should exist in Burma. 



The Ordovician is represented by the Naung- 
kangyi Series and Hwe Maung Series of shale, 
mudstone, and limestone, both of which present 
a varied selection of trilobites (Asaphus, Ampyx, 
Harpes), brachiopods (Orthis, Rafinisquina, Plec- 
tambonites) and cystids (Arystocystis etc.). 

Silurian strata occur in the northern and south- 
ern Shan States. The Panghsa-pye calcareous 
shale and mudstone yield Llandovery graptolites 
(Monograptus, Orthograptus, Climacograptus) 
and other fossils (Acidaspis, Orthis, etc.). Above 
them come sandstone with Bilohites, Pentamerus, 
Phacops, Calymene, etc. followed by the Zebingyi 
beds of limestone and shale with Monograptus 
and Tentaculites. This sequence can be recognized 
in the southern Shan States where the Zebingyi 
beds at Loilem yield a fauna the top of which 
may be Lower Devonian. 

INDIA 

It is sufficient to say here that extensive Cam- 
brian, Ordovician and Silurian deposits are known 
from the Central Himalayas and further west 
from the Salt Range and Kashmir. 

CONCLUSIONS ON THL PALAEOGEOGRAPHY OF THE 
PERIOD 

The problem then is to find the equivalents of 
the Langkawi beds in Peninsular Thailand and to 
trace them northwestwards into Burma and fur- 
ther into Extra-peninsular India. The Upper 
Cambrian of Langkawi can be followed to Teru- 
tau with little change as described on page 294. 
The Terutau beds are probably represented north- 
wards by the Phuket Series which passes laterally 
into the Mergui Series of Tenasserim. Ordovi- 
cian limestones of the Malay-Thai Peninsula are 
represented in Burma by more muddy deposits, 
although thin bands of limestone are present. 
The graptolitic facies extends southwards from 
Burma in a number of phases of which at least 
two in the early Silurian reached as far south as 
Langkawi. The local type of deposition is re- 
versed in the late Silurian and Devonian, with 
predominantly muddy beds in the south, and 
thick limestone deposits in Burma. The relation- 
ship of the Himalayan Palaeozoic to that of the 
Burmese region has not been demonstrated, but 
there is little doubt that they both represent 
manifestations of the same Tethyan cycle, 

Such a correlation provides a guide to a revised 
palaeogeographical reconstruction of Southeast 
Asia. The presence of an immense ocean, the 
forerunner of the Tethys, occupying a region of the 
earth's surface which probably extended east 

297 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



INDIA 



l\ 

Pre-Cambrian\ \ 
Block of 

Peninsular India^ 



SHAN STATES 



A 




o 



Oo 



BURMA 



V 






\ 






\ 






/ 00 uo % 
^THAILAND Oo 

| J 0?0 Oo 
|0 O^CIOO^O 
* A o A 

\0o o o o 
\ o o J o o ! o 

\ooo A - - 





LEGEND 

Land throughout 
Lower Palaeozoic times 

Probable distribution 

of sea during 

Upper Cambrian times 

Further Areas 
transgressed by sea in 
Ordovician times 

Further Areas 
transgressed by sea in 
Silurian times 



APPROXIMATE SCALE I : 15,000,000 

Fig. 5. Sketch plan showing the probable distribution of land and sea during Lower Palaeozoic times. 



Cathaysia 



298 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



from Europe to where the Himalayas now stand, 
has been well established in North India. This 
marine environment first became an important 
feature in the early Palaeozoic, and the nearly 
complete sequence of Cambrian, Ordovician and 
Silurian rocks reported from Kashmir and the 
Himalayas represent the deposits laid down near 
the southern margin of this sea. The Lower 
Palaeozoic cycle in Northern India shows close 
similarities to that of Burma, 'and it seems prob- 
able that the embryo-Tethys continued east in an 
unbroken swing to cover Upper Burma. The 
lateral continuity of beds which can be traced 
from Burma through Thailand to Malaya can be 
explained conveniently by a further extension of 
the embryo-Tethys in the form of an arm exten- 
ding south to the Langkawi area. 

A tentative interpretation of the palaeogeo- 
graphy of the peninsula during Lower Palaeozoic 
times is summarized on the accompanying dia- 
gram (Fig. 5). This indicates the southerly ex- 
tending arm of the embryo-Tethys and demon- 
strates its probable growth from the time of its 
apparent initiation in the late Cambrian to the 
end of the Silurian period when drastic changes 
in its relative position began to take place. 

The marine trough lay between two stable 
blocks of land to east and west. Of these the 
westerly block was the Pre-Cambrian mass of 
Peninsular India which later constituted part of 
the continent which has come to be termed Gond- 
wanaland; the easterly block was the western 
limit of the continent of Cathaysia. The exact 
position of the coastline in late Cambrian times 
is hard to define with any precision, except in the 
south near Terutau where there is some evidence 
in the form of cross-bedding which suggests that 
the Cambrian sediments were derived from a 
landmass immediately to the northeast. The 
absence of further Cambrian deposits in that 
direction tends to confirm this hypothesis. The 
western limit of the sea must have been a con- 
siderable distance away from Langkawi but, as 
the late Cambrian of Langkawi represents the 
most southerly outcrop known to occur, the 
shore lines appear to have joined somewhere to 
the south of these islands. 

During Ordovician and Silurian times the 
marine trough widened, giving rise to deposits 
which now occupy areas reaching far over towards 
the east coast of the Peninsula. A geological 
map of Thailand shows the Ordovician and Lower 
Silurian limestone extending north and east from 
the localities in Malaya to near Surat Thani in 
Thailand. The ensuing deposits of Upper Silu- 



rian and Devonian sediments cover even greater 
expanses of country to the east and north exten- 
ding to near the Indo-Chinese frontier. This 
continued encroachment of Tethys produced, by 
the end of the Upper Palaeozoic, an extensive sea 
passing south over most of Malaya; with this 
event the palaeogeography becomes easier to 
define more clearly. 

The Lower Palaeozoic sea can thus be visualized 
as forming the earliest stage in the evolution of 
the Malayan geosyncline. This stage is repre- 
sented by the period late Cambrian to Devonian 
when the sea proceeded no further south than 
Langkawi, and most development took place 
towards the east. The deep geosynclinal trough 
proposed by Fitch (1951) became well established 
in the time-span Carboniferous to Trias, and 
represents the second stage. The final stage 
culminated in late Cretaceous or early Tertiary 
times with the rise of extensive mountain chains 
to form the Malaya-Indonesia Arc. 

REFERENCES 

Brown, G.F., Buravas, S., et al, 1953, Geologic 
Reconnaissance of the Mineral Deposits 
of Thailand. Geological Survey Memoir 
1. Royal Thai Department of Mines, 
Bangkok. 

Chhibber, H.L., 1934, The Geology of Burma. 
Macmillan & Co., Ltd., London. 

Cowper-Reed, F.R., 1920, Carboniferous Fossils 
from Siam. Geological Magazine, 57: 
1 13-120 & 172-178. 

Fitch, F.H., 1951, The Geology and Mineral 
Resources of the neighbourhood of 
Kuantan. Pahang. Geological Survey 
Memoir 6, Geological Survey, Federa- 
tion of Malaya. 

Newton, R.B., 1925, On Marine Triassic Fossils 
from the Malayan Provinces of Kedah 
and Perak. Geological Magazine, 62: 
76-85. 

, 1926, On Fusulina and other Organ- 
isms in partially Calcareous Quartzite 
from near the Malayan-Siamese Fron- 
tier; Annals and Magazine of Natural 
History 17: 49-66. 

Scrivenor, J.B., 1931, The Geology of Malaya. 
Macmillan and Co., Ltd., London. 

,, and Willbourn, E.S., 1923, The Geo- 
logy of the Langkawi Islands. Journal 
Malayan Branch, Royal Asiatic Society, 
1: 338-347. 

299 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



Van Bemmelen, R.W., 1949, The Geology of Industries of Kedah and Perils. Journal 

Indonesia, la. The Hague. Malayan Branch, Royal Asiatic Society, 

Willbourn, E.S., 1926, The Geology and Mining 4 : 289-232. 



300 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



STRATIGRAPHY OF THAILAND 



SAMAN BURAVAS 
Royal Department of Mines, Ministry of Industry, Bangkok, Thailand. 



Owing to lack of reliable topographical maps of 
Thailand the stratigraphy presented hereafter 
is almost entirely based upon fossil evidences 
backed up by occasional superpositions where- 
ever exposed. A tentative correlation with 
neighbouring countries' formations is also at- 
tempted, so that it may serve as a basis for future 
discussions and final recommendations. 

CAMBRIAN 

A recent discovery of Saukid trilobites and Or- 
thid brachiopods at Tarutao Island (Cambrians in 
map) finally proved that there exists a definite late 
Upper Cambrian formation (1) in the western 
part of the peninsula. The fossils are imbedded 
in a massive brown fine micaceous sandstone 
which has been traced to Langawi Island (Cam- 
brian 2 in map) on the Malay side of the border. 
Trilobites are unfortunately absent over there but 
at Pulao Singha Besar Eophyton or Planolites 
with some casts of a still unidentified brachio- 
pod were found in indurated sandy shale, enclos- 
ing occasional granite pebbles. 

In every respect, the rocks are similar to rocks 
of the Phuket Series (Cambrian i in map) formerly 
described as of tentative Cambrian age (2). This 
formation extends northward along the coast 
right into the southernmost tip of Burma. Eophy- 
ton or Planolites were also found in the Cambrian 
of southwest Yunnan (Mansuy, 1912). Thus it 
seems that the Upper Cambrian system of this 
part of the world extended down from the Yunnan 
Cambrian of China becoming the Chaung Magyi 
Series of Upper Shan States of north Burma, the 
Mergui Series of Lowermost Burma, the Phuket 
Series of Thailand, the Tarutao sandstone of 
south Thailand and the Langawi sandstone and 
shale of Malaya. At present, this Cambrian 
belt has not been discovered further south. 

ORDOVICIAN 

Lower Palaeozoic black limestone known as 
the Thungsong Limestone was found extending 
south from the mountain range east of Nakhon 
Si Thammarat (Oi in map) to Satun (0 3 in map) 
and ending in Perlis of Malaya (0 2 in map). Cep- 
halopods and early corals were discovered (Oi 



in map) and identified as of Middle Ordovician 
age (3). Similar layers (0 ? and0 2 in Tarutao and 
Langawi Islands respectively) with gastropods, 
brachiopods, and a few trilobites, are lying discon 
formably over the Cambrian formation. 

This Ordovician massive limestone formation 
disappears under the sea at both extremities and 
could not be traced anywhere inside Thailand. 
It is doubtful whether this can be correlated with 
the Mawson series of the Southern Shan States. 
The Ordovician of Indochina is more closely 
related to it. 

SILURIAN 

The only occurrence in Thailand is at Sisawat 
(Si in map) NW of Kanchana Bun where Tenta- 
cuiites, Styliolina and some unidentifiable pelecy- 
pods were found in a pinkish fine sandy shale 
underlying Permian limestone. The age was set 
as Silurian (4) owing to similarity with a shaly 
layer of the Burmese Zebingyi series although in 
Indochina a Tentaculites-bearing shale was 
ascribed a Devonian age. 

It is very interesting to note here that the 
apparently continuous black Ordovician lime- 
stone, already mentioned, does include some 
shale beds (north-east tip of Langawi Island of 
Malaya) containing graptolites. These grap- 
tolites were originally thought to be of Caradoc 
age but finally reassigned a possible Lower 
Silurian age (5). Therefore a continuous depo- 
sitional period from Middle Ordovician to Middle 
Silurian age is indicated. The bottom of the 
sea during that time could have been confined 
to the present Thai-Malay border area because in 
Burma and Indochina, the Ordovician and Silu- 
rian formations were definitely differentiated. 

CARBONIFEROUS 

No definite Devonian fossils (except the 
controversial Tentaculites) have been found in 
Thailand. As there are several instances showing a 
disconformity between the Ordovician (possibly 
including Silurian) and the Carboniferous for- 
mation, there must have been a long period of 

301 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



r.,/,v, Siun 

Qrdov 
Camfrrwn 




VOLUME 12 



GEOLOGY AND GEOPHYSICS 



denudation during that period. 



The first Carboniferous fossil collection was 
discovered at a small quarry on the Phatthalung- 
Trang roadside (C 1 in map) and the faunal 
assemblage (trilobites, ammonites, brachiopods 
etc.) suggested a Lower Carboniferous age (6) : 
The second locality (fusulinids etc.) in the Perils 
(Malaya) Padang Besar (Thailand) border area, 
(C 2 in map) is designated ,a Permo-Carboni- 
ferous, probably an Upper Carboniferous 
a e (7)- Fenestella was found in black shale 
below Permian limestone at Prachuap Khiri 
Khan (C 3 ) and the same set-up repeated itself 
(C 9 ) north of Phet Buri. These faunas suggest 
an Upper Carboniferous age (Pennsylvanian). 
Posidonomya and a few trilobites occur in 
Perlis of Malaya (C 4 ), Posidonomya was found 
on an island in the Songkhla inland sea (C 5 ), 
trilobite pygidiums were enclosed in a red fine 
sandstone of Ko Yao (Pulao Panyang) south- 
west of Satun (C 6 ), Argentiproductus (8) abounds 
in dark gray shale of Ko Klang (Pulao Ta Nga) 
west of Tarutao Island (C 7 ), and a gastropod 
horizon cropped out at a district about half-way 
on the Songkhla-Perlis Highway (C g ). These 
are believed to be of Lower Carboniferous age 
(Visean). 

At Wang Saphung 20 kilometers south of Loei 
(C 10 ) a faunal assemblage consisting of fusu- 
linids, gastropods, single corals, crinoid head, 
etc. was discovered and thought to be of Upper 
Carboniferous age. 

These undifferentiated beds have been named 
the "Kanchana Buri Series" and comprise of 
quartzite, quartzitic sandstone, slate, indurated 
shale and calcareous shale with at least two 
bands of non-fossiliferous limestone some of 
which run up to 200 meters in thickness. Corre- 
lation between Thailand and Malaya is definite 
but although the Carboniferous at Loei con- 
tinues into the Laos State and a similar bed 
NW of Chiang Mai continues into the Shan 
States in the north, correlation is quite un- 
certain because of the diversified nature of the 
Plateau Limestone of Burma and the Carboni- 
ferous beds of NW Indochina. 

PERMIAN 

There were numerous places in Thailand and 
quite a few places in Malaya where a massive 
limestone formation (designated "Ratburi Lime- 
stone") of considerable thickness lies above the 
Carboniferous beds, sometimes disconformably 



(southern Thailand) and sometimes unconfor- 
mably (northern Thailand). Shale intercalation 
is found in only one place NE of Bangkok, the 
rest is exclusively limestone. 



The lower part of this limestone (all designated 
P in map because of proficiency of fossil occur- 
rences) contains Fusulinella, Pseudofusulina, Para- 
fusulina, Pseudoschwagertna, Schwagerina, Ne- 
oschwagerina, Verbeekina etc. genera of forams, 
beside Productus, Leptodus (or Oldhamid) and 
various Permian corals especially Sinophyllwn, 
and Wentzelella. These indicate a Lower Per- 
mian age (Sakmarian stage) (9). The top limit of 
this limestone has not yet been defined, but at 
some localities Middle Permian fossils are 
present. Therefore this rock unit is assigned a 
Lower to Middle Permian age. 

Consistency of lithologic nature suggests an 
extensive Permian sea covering Thailand com- 
pletely. The Younger Plateau Limestone of 
Burma, the Makou Limestone of China, the 
Ouralo-Permian Limestone of Indochina and 
part of the Calcareous Series of Malaya may 
have been deposited at the same time. 

TRIASSIC AND JURASSIC 

This formation lies unconformably on top of 
the Permian limestone and is known as the 
Khorat Series. It consists mainly of arenaceous 
sediments in the lower part. The middle part 
varies; in some parts of the country it occurs 
as sandstone and shale with or without salt and 
in other parts it occurs as limestone and shale. 
The top part is limestone, rather isolated and 
confined and its relation with the middle part is 
still not clear. 

Although this formation is most extensive espec- 
ially in the Khorat Plateau (Northeast Thailand), 
where it underlies one third of the country's area, 
fossils are rare. Unidentifiable fragmental bones 
were found in situ while silicified wood and 
occasional Dicotyledones of definite Triassic age 
were collected from the present land surface and 
river gravels on the Plateau itself. Therefore, 
differentiation has not been possible. However, 
outside of the Plateau area, some occurrences of 
Triassic faunas were discovered intermittently and 
more or less definitely identified. 

Myophoria, Trigonodus and other gastropods 
were the first finds (TR^ in a road cutting 
eight kilometers south of Chiang Rai identified 
as definitely Triassic probably Middle Trias- 
sic (10) and the sandstone formation is 

303 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



believed to be the lowest Triassic member in 
Thailand. Lithologically similar sandstone beds 
containing Astarte sp. (11) occur at Chumphon's 
river mouth (TR 3 ). In the north Halobia or 
Daonella (TR 2 ) was found in shale further south 
on the same road from Chiang Rai to Lampang 
and the age was generally set as Triassic but 
later on, its presence with other index fossils 
(Joannites, Balatonites etc.) in shale and lime- 
stone at a nearby locality suggested a late Middle 
to Upper Triassic age ( 12) Daonella is also found 
in a green shale at Na Thawi south of Songkhla 
(TR 4 ). 

A little south of Lampang (TR 5 ) and also at 
Mae Sot west of Tak (TR 6 A.) corals identified as 
Thecosmilia, Margarosmilia, Montivaltfa, Cono- 
phyllia, etc. were discovered and the age is set as 
late Middle to Upper Triassic (13), 

The foregoing beds are similar to the Napeng 
beds of Burma, the Trias of Yunnan, the Trias of 
Indochina and the Trias of Malaya. Daonella 
or Halobia is the common fossil. 

At Mae Sot (TR 6 e.), ammonites (Erycites, 
Tmetoceras and Ludwigia) were present in a lime- 
stone seemingly continuous with TR 6A . As this 
fauna suggests an early Middle Jurassic age 
(14) there is a possibility that the Upper Triassic 
limestone, already mentioned, continues into 
Middle Jurassic time. However, as this is the 
only occurrence of Jurassic fossils in Thailand, 
more work has to be done to ascertain its 
position with regard to the lower two Triassic 
units. At present, only the Namyau beds of 
Burma can be considered related. Other occur- 
rences of Jurassic beds in surrounding countries 
seem to be younger and greatly isolated. 

TERTIARY 

Except at Krabi in Peninsular Thailand the 
Tertiary formations are found in completely ~ 
isolated intermontane basins in the northern 
half of the country. All fossils collected implied 
a late Tertiary age not older than Miocene and 
probably including Lower Pleistocene as well. 

From north to south, the layers of the Fang basin 
oil prospect (TO 150 Km. north of Chiang Mai 
contain small vertebrate bones and teeth, leaves, 
turtle's back plates, insects and a doubtful naticoid 
or viviparus gastropod suggesting a lake deposit of 
fresh or brackish water environment. At Pai 
(T 2 ) east of Mae Hongson, a similar viviparus 
specimen was found. In the present lignite mine 
near Lampang (T 6 ) insects, turtle's back plates, 
viviparus etc. were present and therefore the 

304 



period of deposition here is considered the same 
as at Fang and Pai. 

From the Tertiary bed of Mae Sot (oilshale 
bearing and named the 'Mae Sot Series' T 5 ) 
fresh water mollusks including Viviparus, Taia, 
Margarya, Oncomelania, Hydrobia and Steno- 
thyra (15) were found together with Cyprinid 
fishes, leaves and insects. These indicate a 
Pliocene or Pleistocene age. 

At Phet Buri (TJ southwest of Bangkok, three 
species of terrestrial gastropods of the same age 
f 16) were discovered in a very limited deposit on 
top of a small hill. 

At Krabi (T 3 ) marine gastropods of late 
Tertiary or possibly Pleistocene age are found in a 
lignite bearing formation. It is believed that at 
one time the Tertiary sea may have cut the 
Peninsular in two i.e. extending from Krabi 
northward to and beyond Surat Thani. 

Correlation with the Tertiary of surrounding 
countries is difficult because of lack of definite 
index fossils. Perhaps the Tertiary deposits of 
Shan Plateau and Tenasserim of Burma and the 
Batu Arang Coal deposit of Malaya could be 
considered the same age as the various scattered 
deposits in Thailand because Viviparus or Mar- 
garya and fossil leaves seem to be of common 
occurrence. 

PLEISTOCENE 

Unconsolidated gravel, sand and clay forma- 
tion was found resting unconformably upon 
older rocks in many places, sometimes several 
hundred meters above the general land surface. 
The bed dips only gently with occasional warping. 
Fossil wood and leaves are present but they 
are indeterminable. During construction of a 
bridge at Nakhon Sawan (Pi) fossil mammals 
were scooped up from a depth of 10 meters 
below water level. They were identified (17) as 
being parts of hippopotamus, buffalo, and 
elephant of Lower Pleistocene age not unlike 
those from the Siwaliks of India. The nature 
of the containing beds is not known but quartz 
and quartzite gravel fills the cavities of the fossils. 

At present, correlation with surrounding coun- 
tries is impossible. 

ANCIENT MAN'S IMPLEMENTS 

Paleolithic chopping tools and other primitive 
implements made from river gravel of quartz, 
quartzite and hard siliceous slate were found in 



elevated river terraces just north of Chiang Mai, 
a little north of Lop Buri and 44 kilometers 
northwest of Kanchana Buri. Neolithic finds 
were present in at least 40 localities. They are 
rather scattered in the north from Phet Buri up, 
but in Peninsular Thailand there are two definite 
trends, one starting at Chaiya south to Krabi and 
the other south from Nakhon Si Thammarat to 
Satun. Southeast of those the neolithic artifacts 
are rather scattered but extend southward into 
Malaya and a communistic mode of living upon 
stream or river banks is apparent. 

Only animal bones are met with because in 
every place where human or human-like remains 
were discovered, they were all cremated so that 
the owner's spirit will be able to re-incarnate 
somewhere #nd somehow! This is quite a set 
back to the tracing of migration routes of pre- 
historic man in this part of the world. 

There is a definite gap between Phet Buri and 
Surat Thani and further south in which no record 
of either Paleolithic or Neolithic artifacts were 
ever recorded. It is believed that the migration 
route could have been effected either southward 
or northward along that stretch of rising sandy 
beach east of the Peninsula. 

Animal bones had been found with the arti- 
facts at a place about halfway between Sukho 
Thai and Tak (foreleg bone of a mountain goat) 
and also at a place a little south of Surat (un- 
identifiable). 

There is still a great controversy between 
historians and archeologists whether migration 
of ancient man in Thailand was from south to 
north, from north to south, or both. 

LIST OF EXAMINERS OF FOSSILS 

(All personal communications except when 
publications are mentioned). 

(1) Prof. T. Kobayashi, 1956, Geological Insti- 

tute, University of Tokyo, Japan. 

(2) Dr. H. Duncan, 1949, U.S. Geological 

Survey, U.S.A. 

(3) Dr. G.A. Cooper, 1956, Smithsonian Insti- 

tution, U.S. National Museum, U.S.A. 

(4) Dr. G.A. Cooper, 1946, 
Dr. H. Duncan, 1949, 

(5) Dr. R. J. Ross, Jr., 1956, U.S. Geological 

Survey, U.S.A. 



VOLUME 12 GEOLOGY AND GEOPHYSICS 

Prof. O. M. B. Bulman, 1956-1957, Sedgwick 
Museum, University of Cambridge, 
England. 

Dr. H.W. Ball, 1957, British Museum (Nat- 
ural History), England. 

Dr. I. Strachan, 1957, Birmingham Universi- 
ty, England. 

(6) Dr. F.R. Cowper Reed, 1920, Carboniferous 

fossils from Siam: Geol. Mag., 57: 
113-120, 172-178. 

(7) Dr. R.B. Newton, 1926, Annals and Mag. 

Nat. History, 9th ser., 17 : 49-64. 

(8) Dr. Mackenzie Gordon, Jr., 1956, U.S. 

Geological Survey, U.S.A. 

(9) Prof. Carl. O. Dunber, 1939, Personal 

report on A Heim and H. Hirschi's 

collection. 
Prof. R. Toriyama, 1944, On some Fusuli- 

nids from northern Tai: Japan Journ. 

Geol. Geogr., 19: nos. 1-4, pp. 243-248. 
Dr. M. Minato, 1944, An Occurrences of 

Wentzella Subtimorica in northern Tai, 

Proc. Imp. Acad. Tokyo ; XX. 
Dr. L.G. Henbest, 1949, U.S. Geological 

Survey, U.S.A. 
Dr. H. Duncan, 1949. 
Dr. G.A. Cooper, 1949. 
Dr. K. Konishi, 1953, Trans. Proc. Palaeont. 

Sec. Japan, New Series, 12 : 103-1 10. 

(10) Dr. T.W. Stanton, 1923, Personal report 

on W. M. Lee's collection. 

(11) Dr. R.W. Imlay, 1956, U.S. Geological 

Survey, U.S.A. 

(12) Dr. B. Kummel, 1952 and 1954, Museum of 

Comparative Zoology. Harvard Univer- 
sity, Cambridge, Mass., U.S.A. 

(13) Dr. J. Wells, 1956, Cornell University, 

Ithaca, N.Y., U.S.A. 

(14) Dr. R.W. Imlay, 1949. 

(15) Dr. T.C. Yen, 1949, Smithsonian Institu- 

tion, U.S. National Museum, U.S.A. 

(16) Dr. T.C. Yen, 1949, Smithsonian Institu- 

tion, U.S. National Museum, U.S.A. 

(17) , , 1941 , British Museum of Natural 



History, England. 



305 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



THE SUCCESSION OF NAPPES IN THE WESTERN MIOMAFFO AREA 

OF THE ISLAND OF TIMOR: A POSSIBLE KEY TO THE 

STRUCTURE OF TIMOR 



P. MARKS 

Geological Institute -, Faculty of Science, University of Indonesia, Bandung, Indonesia. 



During an expedition made for the Faculty of 
Science of the University of Indonesia in Ban- 
dung to the Western Miomaffo area in the North 
Central part of the Indonesian half of the island 
(Fig. 1), a clear picture was obtained of the 
succession of the overthrust units for which this 
island is so justly renowned. In the area, re- 
markable for the number and excellence of 
outcrops, most of the rockunits known from 
other parts of Timor have been recognized, vis. 
the: 

Kekneno Formation, represented here as elsewhere 
by claystones and shales, often of a vivid 
lightblue colour, locally with intercalations of 



red and green coloured shales and thin bedded 
limestones in its upper parts; well bedded 
graywackes and graywacke shales, sometimes 
containing Halobia in more calcareous layers; 
limestones and shales in regular alternation. 
From top to bottom the following members have 
been recognized (Fig. 2) : 

Blue clay of varying thickness, sometimes marly, 
locally absent; limestones and shales, often 
darkcoloured, strongly folded, sometimes varie- 
gated and cherty varicoloured shales; 

Well bedded graywackes, with tuffaceous com- 
ponents and even occasional agglomerates of 
volcanic origin forming the most competent 




- -- Route of |57 expedition 



nAr 
I9 



mapped by 
I9S7 expedition 

O IP 20 40 6O 8Q lOOKm. 



Fig. 1. 



306 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



SUCCESSION OF ROCK FORMATIONS IN WESTERN MIOMAFFO AREA, NW TIMOR 



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RHYOLITIC AND QUARTZ KERATORHYRlC 
TUFFITES AND TUFFACEOUS MARLS 
WITH OUTFLOWS OF DIABASE 
PILLOW LAVAS AND ROPE LAVAS 

ITES AT CONTACT OFTEN 
SILICIFIED 
BLACK SHALE LOCALLY DEVELOPED 



BASA,L CONCLOME R j AJ E_. 
ANGULAR FRAGMENTS OF SCHIST IN DETRITALSCHIST MATRIX 




AMP HIB OL I TE, GREEN SCHIST, MUSCOVITE - 
GARNET SCHIST, PHYLLITE ETC 
IN NOIL BESI INTRUSION OF GRANODIORITE 
BODY AND APLITE DIKES 



UPPER THRUSTPLANE 



THICKBEDDED FOSSILIFEROUS LIMESTONE 
WITH LOVgENlPORA VINASSAI LATERALLY PASSING 
INTO RED THIN-BEDDED LIMESTONE AND CHERT, 
LOCAL LENSSHAPED MASSES OF LIMONITE -HAtMA 
TITE. BASAL CONGLOMERATE LOCALLY DEVELOPED 



MICACEOUS SANDSTONE AND CLAY WITH - 

TUTEN MERGEL" ZONE OF LANDSLIDES 



T_RQCHITE LIMESTONE MEMBER. 
THICKBEDDED RED LIMESTONE S W PERMIAN POSSIU 



PILLOW LAVA MEMBER. 

OJ-CANICS AND SERPENTINES, SO 



lOOm- 

to - 

BO 

7O 
O 

SO 
4O 
90 

ao 

10 

k o 



.^ .IT . > ^ vy 



". .* ? ? F t r 



I I I I I I I I I I 



1 I I I I I I I I 1^ 



I I 



I I I I 1 I 1 I _J_ 



1 . ' 



-ii I I i i I ._ 



I ' I I I I I I 7 I I 1 



LOWER THRUSTPLANE 



ii Jffil 



THINBEO 
VARIEGA 



UP 

J5TH 



A ,MtI 



GRAYWACKE MEMBER 

THICKBED. GRAYWACKES,SILTftTOMIS,SHALtS- 
AND CONGLOMERATES^OFTEN TUFFACIOUS, 
WITH OCCASIONAL INTERCALATIONS OF AGGLO - 
MCRATCS 
GRAYWACKES USUALLY MUCH OIACLASCO 



HAUQDIA In^LL M6MP6B 

SILTSTONES AND SH ALE S, BROWNISH - G RE EN 
IN COLOUR WITH ABUNDANT 



LOWER C AL CAR CPUS MEMBER. 
WELL BEDDED FINEGRAINED LIMESTONE 
ALTERNATING WITH SHALE AND MARL. 
THIS MEMBER USUALLY WITH COMPLICATED 
DETAIL-FOLDING 




BRECCIA CONGLOMERATE 



PLASTIC 

CLAY 



DRAFTED BY OR P MARKS 
DRAWN BY E SUDARMA 
OKT 1*57 BANDUNG 



Fig. 2. 



307 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



member; Khakicol cured shales with calcareous 
intercalations, often containing zones with 
Halobia; 

Well bedded limestones alternating with shales, 
usually strongly folded. 

The Sonnebait Formation, in which the following 
succession could be recognized : at the base pillow 
lavas of basaltic composition, very often with a 
pronounced vesicular or amygdaloidal texture, 
only locally developed ; 

Thickbedded limestones with numerous fragments 
of Echinoderms, alternating with beds of con- 
glomerates, often reddish in colour, probably 
Pemian in age. 

Bluegray clay with intercalations of marls and 
muscovitic sandstone [the latter often shows 
curious surface markings ("Rill-marks" caused by 
back flowing water on wave-swept beach) while 
the marls are often characterized by cone-in-cone 
structures ("Tiitenmergel")]. The clay very often 
contains gypsum in beautiful crystals ("swallow- 
tails"). Fossils have not been encountered in this 
member. 

The upper part of the Sonnebait formation is 
represented by thinly bedded wine -red and 
variegated limestones with Halobia sp., which are 
very often siliceous (chert) and have been 
observed to pass laterally into almost purely 
ferriferous deposits on the one hand (limonite or 
haematite) and on the other hand into thick 
bedded corraligene limestones in which the chert 
bands of the red limestones may be recognized 
as layers of flint or chert, usually strongly broken 
and deformed. The latter development is known 
as the Fatu Limestone, as the limestone masses 
have often been isolated by selective erosion to 
form towering masses in the Timorese landscape 
called "Fatu" in the local language. They 
represent typical bioherms in a surroundings of . 
therwise mainly clastic deposition. Fossils in 
the Fatu (Lovcenipora vinassai) indicate a Trias- 
sic age. 

The entire Sonnebait Formation is at best a 
few hundreds of meters thick, and does not 
represent a typical geosynclinal deposit. The 
depositional surroundings suggest an offshore 
basin with recurrent lagoonal conditions, possibly 
separated from the open sea by a fringe of reefs 
or biocherms formed by tabulate corals and 
hexacorals, as well as sponges and brachiopda. 

This lagoon deposition was strongly influenced 



by the adjoining landmass, on which during 
triassic times a wet tropical climate and lateritic 
weathering may account for the red colour of 
the upper Sonnebait deposits, as well as for the 
deposition of chert and limonite which charac- 
terize this member. 1 This possibility is rein- 
forced by the presence in one place of an alter- 
nation of coarsely crystalline pure limestones 
with sandstone containing silicified plantremains, 
which may be explained as chemical deposition 
in evaporating waters of a lagoon, alternating 
with windblown sands and plant fragments. 

The Tertiary is represented in this area by 
black shales containing large Rotalia, intercalated 
in lightcoloured tuffites of probably rhyolitic 
composition. Locally intercalated in this suc- 
cession are numerous flows of diabase often 
with excellent pillow -and rope structures. The 
texture of the flows varies from coarsely crystal- 
line to glassy and vesicular. 

The tuffites-clays are often silicified in the 
proximity of the diabase flows. The Tertiary 
(Burdigalian) age is assumed because of the 
similarity to fossiliferous formations known 
from adjoining areas (Marks, 1955). The Miocene 
formation sometimes disconformably overlies a 
formation of highly metamorphic rocks, consist- 
ing of amphibolites, greenschists, phyllonites, 
biotite-garnet schists, etc. and is usually separated 
from this formation by a distinct basal conglom- 
erate composed of large and rather angular 
fragments of metamorphic rock. The discon- 
formity, however marked, is a normal strati- 
graphic one, and the schist-tertiary succession 
has to be considered as composing a single 
unit. 

Last but not least there occur in numerous 
places seemingly disconnected masses of ser- 
pentine, in close association with a usually strong- 
ly weathered and crushed basic volcanic rock. 
Together they form the ophiolite-spillite asso- 
ciation of Brouwer et al. 

In the Western Miomaffo area the following 
succession could be established (Fig. 3) : 

The Kekneno Formation forms the lowermost 
unit and quite probably represents the para- 
autochthonous; 

Overlying this formation, and always separating 
it from the Sonnebait Formation, is the Ophiolite- 
spillite Formation (0-S), which is not represented 



i Twenhofel, W.H., 1939 Principles of Sedimentation, First edition p. 372, 373, 381, 382, 387. 
308 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



sw 



IDEALIZED SECTION SHOWING THE SUCCESSION OP TECTONIC UNITS IN THE MIOMAFFU AREA 
NORTH CENTRAL INDONESIAN TIMOR 



FATU 
1 




SONNEBAIT 
FORMATION 
WITH FATU LIMESTONE 



DIABASE FLOWS 

AND TUFFITES OF MIOCENE 

WITH BASAL CONGLOMERATE 



PARAAUTOCHTMONOUi 



LOV'R NAPPE 



Fig. 3. 



everywhere and may have been squeezed out to 
form a number of lense-shaped masses; 

The O - S formation is always overlain by the 
Sonnebait Formation of which the Fatu Formation 
forms an integral part, in fact only represents 
a facies-member of the Sonnebait (Fig. 2), 
laterally passing into thinbedded red or variegated 
limestones and cherts. Together with the O - S 
formation the Sonnebait-Fatu Formation forms 
the lowermost overthrust unit or nappe. Over- 
thrusted on this nappe is a unit composed of the 
metamorphic rocks, disconformably overlain by 
Tertiary rock, either Eocene (not represented 
in the Miomaffo area) or Lower Miocene, and 
almost invariably divided from the Sonnebait by 
a mylonite zone. 

This schist-tertiary unit forms the second and 
uppermost overthrust unit in the Timor nappes, 
and is only represented by isolated "Klippen" or 
rootless masses, localized usually in steeply 
infolded synclines. In some areas intricate 
"Schuppen" structures have been formed of the 
schist-miocene and the sonnebait units. 

The structure of the area is characterized by 
the occurrence of a great many parallel steeply 
folded, sometimes even overturned, synclines and 
anticlines. The synclines are characterized by the 
presence of upper Sonnebait, often in Fatu 
Fades, or even remnants of the overlying schist 
tertiary nappe. The anticlines often have Kek- 
neno exposed in the core, or if erosion has not 
reached this formation, are characterized by 
ophiolite spillite, lower Sonnebait volcanics or 
permian limestone. The quick succession of the 
extremely narrow folds has given rise to the 
impression of a "Mega Breccia" as the true 
succession of the formations was not always 
clearly understood. 



Much of the mix-up is due to the following 
circumstances : 

1). The diabases and basalts, which in the 
Northwestern part of Timor occupy much of 
the Miocene succession, and which, especial- 
ly to the North of the Mutis and in Oicusi, 
strongly resemble the igneous rocks of the 
Ophiolite spillite formation, and especially 
when crushed and mylonized are almost 
undistinguishable. 

They may be separated only by their 
association with the lightcoloured acid 
tuffaceous rocks of the Miocene. Thus 
the "Ophiolite spillite Complex" is some- 
times described as underlying the schists 
(although no sections have been published in 
which the schist is actually in direct contact 
with the serpentines and spillites, while 
numerous sections, show that the formations 
are separated by Fatu Limestone and/or 
Sonnebait) in the case of the "true" 
Ophiolite-spillite Formation, and as over- 
lying the schist when in reality Miocene lavas. 
Especially in the Fatu Kaslioe area this 
succession may be observed in the maps and 
sections provided by De Roever. 

2). A second reason is the uncritical attribution 
of the calcareous-cherty upper part of the 
Kekneno to the Sonnebait Formation. In 
this way the Ophiolite spillite Formation is 
sometimes described as overlying the Sonne- 
bait, sometimes as being overlain by the 
latter formation. 

A correct evaluation of the (Cretaceous?) 
cherts and limestones as the upper part of 
the Kekneno greatly reduces the number of 
seemingly complicated tectonic situations. 

309 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



3). In the third place, the suppostion that the 
Fatu Limestones form a separate tectonic or 
stratigraphic unit has also unneccessarily 
complicated the tectonic interpretation. 

In the area studied by the 1957 expedition, 
the Fatu limestones are clearly the upper 
member of the Sonnebait, their topographic 
high position often being due to their defor- 
mation into narrowly pinched anticlines, 
together with their greater resistance to 
erosion (Fig. 3, SW part of section). In fact, 
the schists and their autochthonous covering 
of Tertiary are often lying in narrow syn- 
clines completely surrounded by Fatu Lime- 
stone which distinctly dips away underneath 
the metamorphics. A clear example is 
given in fig. 15 of De Roevers publica- 
tion. 

Thus, the possibilities indicated by Brou- 
wer (1942) and Van Bemmelen (1949, 
p. 517) are entirely confirmed, except that 
these authors have assumed the Fatu 
Limestone to overlie the metamorphie for- 



mations. The final results of the 1957 
expeditions will be published in the course 
of 1958, and it is hoped that a more extensive 
application of the above described results 
to earlier work in Timor can be given. 

REFERENCES 

Roever, W.P. de, 1940, Geological Investigations 
in the Southwestern Moetis Region 
(Neth. Timor) in Geological Exped. to 
the lesser Sunda Islands, etc. pp. 240 ff. 

Brouwer, H.A., 1942, Summary of the results 
of the expedition Geological Exped. 
to the lesser Sunda Islands etc. 4: 
345-402. 

Marks, P., 1955, An occurrence of Miogyp- 
sina complanation Schlumberger in the 
Lalan Asu area, Timor. Ind. Journ. 
Nat. Sc. 1955:78-80. 

Waard, D. de, 1954, The second geological 
Timor expedition, preliminary results. 
Ind. Journ. Nat. Sc. 1954: 154-160. 



310 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



STRATIGRAPHY OF WESTERN AUSTRALIA A SUMMARY OF 

RECENT DISCOVERIES 

J. R. H. McWHAE 

Perth, West Australia. 



INTRODUCTION 

Excellent reviews of the stratigraphy of Western 
Australia have been published by Teichert 
(1947, 1950) and Fairbridge (1953). More 
recently, a review that includes all the important 
advances in the stratigraphical knowledge of this 
State has been compiled by McWhae ef al (1957 
ms.). The present summary deals particularly 
with the more important additions to this know- 
ledge since 1950, and is based on the work of 
McWhae and his co-authors. Precambrian 
stratigraphy is not discussed. 

The new discoveries are indicated in Fig. 1, 
in which the present knowledge of the strati- 
graphy of the intracratonic basins of the State is 
illustrated. The locations of these intracratonic 
basins are shown in Fig. 2. High-angle faults 
are more strongly developed than folds in 
the basins, as no major orogeny has affected 
Western Australia since Precambrian times. 

The author wishes to thank the Management of 
West Australian Petroleum Pty. Ltd. for per- 
mission to publish this paper. Recent ad- 
vances in the knowledge of the State's strati- 
graphy have resulted mainly from the explora- 
tion activities of this company, the Bureau of 
Mineral Resources (Canberra) and students and 
staff of the Geology Department of the University 
of Western Australia. The writer is deeply 
indebted to the geologists of these organizations 
for their contributions to this summary. Specific 
acknowledgements are given in McWhae et al. 
(1957 ms.). 

STRATIGRAPHY 

CAMBRIAN 

Cambrian marine sediments have been known 
from the Bonaparte Gulf and Ord Basins for a 
considerable time. Both Teichert (1947, 1950) 
and Fairbridge (1953) have described the se- 
quences, and more recently a comprehensive 
paper has been published by Traves (1955). 

Marine Cambrian rocks are not known in 
other Western Australian basins, but an exten- 



sive development of tholeiitic basalts, agglomer- 
ates, tuffs and associated dykes occurs discon- 
formably below the Cambrian sediments in the 
Bonaparte Gulf and Ord Basins. These are 
generally considered to be Lower Cambrian in 
age. They reach a thickness of 3,300 feet in the 
Ord Basin (Traves, 1955) and are correlated, 
tentatively, with similar volcanic rocks in the 
King Leopold Range immediately north of the 
Canning Basin (Guppy et aL 9 1957). 

The extensive dolerite dykes that intrude the 
older rocks of the State have been related to this 
taphrogenic period by most authors. However, 
recent advances in stratigraphical knowledge 
have shown that there are three other periods 
when similar suites of basic igneous rocks were 
formed. The first of these is probably Ordovi- 
cian or Silurian in age and affects the Moora 
Group rocks of the Perth Basin; the second 
occurred probably in Triassic or Jurassic times in 
the northern part of the Canning Basin (the 
Fitzroy Basin); the third is known in the southern 
part of the Perth Basin where tholeiitic basalt 
flows are interbedded with sediments of Lower 
Cretaceous or uppermost Jurassic age (McWhae 
et al, 1957 ms.). 

ORDOVICIAN 

Ordovician rocks were positively identified in 
Western Australia in 1949. Some sections are 
described in Fairbridge (1953), but a more de- 
tailed account is given in McWhae et al. (1957 
ms.) 

A Lower Ordovician greensand formation, 
the Pander Greensand, is known in the Bona- 
parte Gulf Basin (Traves, 1955). In the northern 
part of the Canning Basin a marine sequence, 
over 2,600 feet thick, is exposed in a very 
restricted area (Guppy & Opik, 1950). It is 
considered to be Lower and early Middle Ordo- 
vician in age. 

Logan and Chase (1956 ms.) discovered 
problematical fossils, which Dr. D. Hill and 
Dr. A.A. Opik consider to be older Palaeozoic, 
in rocks formerly considered Precambrian in 
age, in the northern part of the Perth Basin. 

311 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



SEDIMENTARY BASINS 

WESTERN AUSTRALIA 




312 



Fig. 1. 



VOLUME 12 



GEOLOGY AND GEOPHYSICS 



ERA 


PCRIOD 


BONAPARTE 
GULF 
BASIN 


ORD 
BASIN 


CANNING 
BASIN 


CARNARVON PERT 
BASIN BASIN 


H COLLIE, 
1 MUJA, 
WILGA 
BASINS 


EUCLA 

BASIN 


LEGEND 


C 
A 
1 
N 

Z 

1 
C 


Quaternary 


c 
c 








c 
c 
c 








c 

c 








c 




C 


c 
c 

c 




c 








cm 


Pliocene 




















J. 

IS 


\~ 


















J? 

': 


5O' 




Miocene 










c 

37 


1 






















I4O 


O 


j 


em 
" 


Oligocene 


















Jon 
C 








J3 




_ 7 _ 








7 


cm 


Eocene 




















50 








450+ I.OOO 

1 i )7 






T 


200 
_ 7 


M 


Palcocene 




























IbO + 






? 








xxxx 


M 
E 
S 
O 
Z 
O 
1 
C 


Cretaceous 




























8-50 ?00 








J 7 

M5C 



4- 








D.tcovtrtd smct 
Tfichft (I95O) 

Diicovrrcd iinc* 


2500 *25 


Jurassic 




















2.000 +- 


T* 


50C 

^ 


,+.c - 
eooc 


>+ 
















ISC 
I,OC 

ix 








c 






Triassic 












^ 

0* 
3O + 

TD 

14,0 

-j 


_ 

7 
00 

a 

3 
? 
6O 


-f 

" 
7 




















I nnr.'f 


-f ' 


p 

A 
L 
A 
E 
O 
Z 

1 
C 


Permian 


L, 
soo 


^x 


^ 














~T 
i 


400 

1 

73C 


T 
6500 


* 3OOO 












5OO 


^ 


Carboni- 
ferous 


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^ 

-L 


J7L. 

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140 

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Devonian 














































i 


Silurian 
































_ | "" 






4- 

PALAEOZOIC AND 
YOUNGER SEDIMENTS 
IN 
WESTERN AUSTRALIA. 


6000 
c IOOOC 


3OOO 

T 


Ordovician 






















I 










2600* t" 


Cambrian 


2*00-^ 

3OOO 








































35OO 


1957. 




^^^^^^^^H 3 3OO+^^^^ft* l T llll t^ P r 










APPROXIMATE MAXIMUM 
THICKNESSES FEET 


I4,OOO 


3,500 


34,OOO 


47OOO 5O,OC 


O* 3,OOO 


2,50O* 


-*-*..- 



Fig. 2. 



313 



PROCEEDINGS OF THE NINTH PACIFIC SCIENCE CONGRESS 



This sequence, known as the Moora Group, is 
approximately 4,500 feet thick and consists of 
cherts, siltstones, sandstones and arkoses. It 
may be correlated in part with an extremely 
thick sequence of unfossiliferous siltstones, sand- 
stones and conglomerates known as the Yanda- 
nooka Group. This group is developed in a 
huge syncline east of Yandanooka, where it 
attains a thickness of approximately 30,000 feet 
(McWhae et al, 1957 ms.). 

SILURIAN 

Silurian rocks were unknown in Western 
Australia prior to 1957, when West Australian 
Petroleum Pty. Ltd. drilled a test well (No. 
17 B) on Dirk Hartog Island in the western part of 
the Carnarvon Basin. Dr. B.F. and Mrs. Glen- 
ister discovered Silurian conodonts in a cal- 
careous sequence 2,425 feet thick penetrated by 
this bore (McWhae et al, 1957 ms.). The se- 
quence is overlain unconformably by Cretaceous 
sediments, and passes downwards conformably 
into an arenite succession correlated with the 
Tumblagooda Sandstone. Besides conodonts, 
the fauna of the calcareous section includes 
nautiloids and brachiopods with Silurian affinities. 
The unit is considered Silurian in age by Dr. and 
Mrs. Glenister, and also by Dr. Opik. 

The Tumblagooda Sandstone (Clarke & Tei- 
chert, 1948) is over 3,500 feet thick in the type 
section in the lower part of the Murchison River, 
but exceeds 6,000 feet in other sections. It is 
regarded, tentatively, as possibly Lower Silurian 
in age as beds correlated with the Tumblagooda 
Sandstone interdigitate with the lower part of the 
fossiliferous, calcareous sequence in the Dirk 
Hartog bore. The unit consists of various 
sandstones, sometimes arkosic and conglomeratic, 
and red s