Ni ate aera i DAR irr A raf _ VTA H iD ~ Fs Va Y ' > i ¥ ia Rea jaeds Hale Oceanographic institution | \\ TECHNICAL REPORT SUBMARINE GEOLOGY OF THE TONGUE OF THE OCEAN, BAHAMAS NOVEMBER 1962 (Reprinted 1968) ; 743 NAVAL OCEANOGRAPHIC OFFICE WASHINGTON, D.C. 20390 | IU: TR-/)3 Price $1.20 a ABSTRACT Seventy-three sediment cores, 6 grab samples, and 4 stereographic camera tracks were taken on the bottom and flanks of the Tongue of the Ocean, Bahamas. The Tongue of the Ocean is a long, deep re-entrant or channel into the Great Bahama Bank. It is oriented northwest-southeast, is about 700 fathoms deep in its southern portion (cul-de-sac), and gradually descends northward to 1,300 fath- oms over a distance exceeding 100 miles. The flanks or walls of the channel are precipitous and average 15° to 20° slope above 250 to 300 fathoms depth; how- ever, the slope below this depth range to the bottom is more gradual. Incised into the flanks are deep gullies trending at right angles to the surrounding bank edges; the gullies are more prevalent in the long, narrow northern portion of the channel than in the southern cul-de-sac area. Laboratory analyses show the bottom sediment to be predominantly silt-sized skeletal and nonskeletal carbonate particles of both deep and shallow water origin. Organic carbon content of the sediment is low, averaging between 1.0 and 2.0 percent. Water content, void ratio, and porosity decrease with depth in the sedi- ment, while conversely, density and cohesion increase. Sediment accumulation in the channel can be attributed to slow, continuous particle- by- particle deposition from the overlying water column and _ turbidity current type deposition originating on the upper walls and bank edges of the channel. The latter type accumulation accounts for over 50 percent of the sedi- mentcolumn sampled. Rate of sediment accumulation is extremely high along the flanks and central reaches of the southern portion in the channel. Radiological dating shows accumulation as high as 640 cm/1,000 years at selected areas. Sediment accumulation in the northern, central area of the Tongue of the Ocean is much less and is measured at between 3 to 5 cm/1,000 years. Stereographic photographs of the channel bottom show a paucity of benthic animal or plant life, and, in general, an almost featureless unconsolidated ooze is pictured. In the central, northern portion of the channel at 1,000- fathoms depth, a limestone outcrop is present containing cavities or basins suggestive of subaerial erosion at some earlier geologic time. Adjacent to the outcrop are well-developed symmetrical ripple marks probably caused by tidal oscillations or internal waves, ‘and, on the basis of ripple form and dominant sediment grain size, bottom cur- rents of between 0.3 to 1.0 knot are calculated. ROSWELL F. BUSBY Oceanographic Development Division il WT L/w MB NA FOREWORD This report brings up-to-date all the information and observa- tions collected by this Office concerning the submarine geology of the Tongue of the Ocean, Bahamas. Reports and work of other agencies and individuals have been used where necessary in the preparation of this Technical Report. Research work on the submarine geology of the Tongue of the Ocean is continuing, but the major concentration now is on the shallow banks surrounding the channel. It is believed that the analyses contained in this report will contribute significantly toward the understanding of the complex marine environment found in the Tongue of the Ocean area. Commander mn m O 0301 PREFACE The investigations of the submarine geology of the Tongue of the Ocean reported herein were begun in 1961. The author, Roswell F. Busby, has been active in collecting the data as well as in performing the laboratory analyses and interpreting the results. The author would like to acknowledge the following personnel from the Oceanographic Office: W. E. Maloney for providing support and permission to pursue the investigations, G. H. Keller for performing the bulk of the engineering tests and for offering suggestions in the preparation of the report, and B. K. Swanson for critically reviewing the manuscript. The author would also like to express gratitude to the Marine Laboratory, University of Miami, for use of their laboratory facilities, and to Dr. Gene A. Rusnak for making available information and figures in advance of a forthcoming paper and for his many helpful suggestions and encouragement in the preparation of this report. Finally, appreciation is extended to Commander R. L. Sattler and the officers and enlisted men of the USS SAN PABLO (AGS~-30) for providing the means and assistance in collecting the samples and observations used in the report. a 1 iy TABLE OF CONTENTS Page FOREWORD tettens ste Tee Nae top, ehh lta Paka eta Way ue a De eR Sit I ili PREFAGE. yes. Eutoclee SP ow ke RGA ARE el LPCYN cuit tin Made esate Vv FIG WIRES ies aha toc Aarti cet Aten cin Fey iba AV Nh oe yey lace Ree Rb ham Vili PAB prete yan ectnte cu coronas, vey vey SES EC Hak Seppe teomnroayres Rarnuayt Newiwcmaeh Rel ren iseet <1c vill BEATTIE Sareieccre ees eessiae nee resell stoi’ etka ctohrsw cov SrammmrouurcnVenayommnise Wormueuilene ueca evel irene Rar Meueee. so ix ZNPPREINID UT XGiiitak wresecw, cavers tek Lebivcub tree venereal Rid vlc ts wants ud awa ane Sea hi ix LINTRODUGTIONE arcu SVL saR RA We hakcrptehr Sy vcaN nae Maen PINS yeaah acticin is | Purpose of the Investigation . ......-. BO Op a, Chart SOL OL Oana ] Deseniptiomof thexArea) 6 «1 « eiicl © fe 6 5) | GHLOREAIRCR Oo Vicnaemmes 1 REV Ol ERIMINIENT IUTeRVAIUWINS 5. 6666660500600 66 50506 6 The Bahama Platform ........-. Eres seilkey Meal orerowune Some SE eaehwe iow Mhetiongue ofthesOcean\ 45) Salat cr\s outa viele el « sit'ec 6 ss 6 © el, of PRESENITBIINVESTINGATIONG Ge vote ie sl re noe votes Goer deen or SECS wanes 9 Field Procedure ..... sae fein ley co lasey Oatroutel Lata) ceteeo een de) te selmi ts 9 EQDOrahOnyeAnGiySeSmmser nei nret et cunclits iiolire lier Licls tet eolbusil ou tet niet fonts) oi tarts 9 SED IMIEIN Stree eestor tice etree scjure e” Cen, ae nae ee te ce ties Ice 13 Generally site encase eave romana r ants. hace: Wa tettetire hie. okbicn art vosluey is ee ae 13 Near-flank Sediments ........e Stroh roan seiltciatl crn cavaceuttei de ays tek aaa AM Axial Sediments ...... Mpiaian Men Mesa ahices Way Ler nioh Get Gmc oer e EN oe lees 25 Gul=de=sacsSediments)) se cine ieee ene eles Sue advel Ne atattarn ot astatentee 33 RATE OF SEDIMENT ACCUMULATION ........- SRR Nal Re evra so dlaee 45 ENIGHNIEERIINGG “PROPERTIES”. ivctecnerot troy u/entyors larevorbarary Reniemmcta tna oucn'sn! « Geueetn ve 48 Shear Strength. sesvey ear < Hoereiieiy mane: cWEobre su bichascolibeigus: yeyecei ins wey cere 48 Sensi bivity. |) Jesse) ro yeen lens Pu Homa Silo ABe! OOM om OF. ORO OG 57 BOTMOMPPHOMO.GRA PHN) cree sean are its om Saar cnucry reuse uei enc kitts s 6 ps8 GamerarStathioniDctai i) wieunene sy... opremmants Wicd iednc. ueeliccee eimcwciien Sincaiiee ce 58 BiolOgyamenmenas \tottee cho de cu cl 's, ~oplctatoueel an rs. \o! <6 rec Baty LOCO OIE 60 Bottomskeattinesm cavers so totin ce eo ete Me rate” eer Us Wenel cee ce RRP Rar sie 61 BotfiomuGurnemts: woeek tetweuie he nisi ui ah eye rs deeoseugvs. WellereultenieVneumeimtoutey te ve 62 SWIMMARNG? 2 oor e eae Oe ee 8 Se oS SRS So Re eee 64 REEERENGES CITED ere te eon 5 en eee tae tens) eed RATE nate CAMO T UR! 66 eo? vil FIGURES Page UV Belnetna Petia 5 5650000500006 Siva cclee iat ots ot ch uk Seren Oe 2 Bathymetry of the TOTO (after Athern, 1962a) (fold-in) ...... 3 3 Longitudinal and Cross Sectional Profiles of the TOTO ........ 5 «2 A Sediment SampliingpStationsmintheml@Ol@mw ma) re es) ee ee outen ete 10 5 Location of Deep-sea Camera Lowerings and Vertical Profiles ...... II 6 Areal Distribution of Sediment Types inthe TOTO ......... x 4 7 Longitudinal Cross Section of Near-flank Cores (fold-in) ...... I7 8 Longitudinal Cross Section of Axial Cores (fold-in) . .......-s 27), 9 Longitudinal Cross Section of Cul-de-sac Cores (fold-in) ...... 39 10 Rate of Bulk Sediment Accumulation at Selected Locations in the TONO™ > 4 fe PCO er ee eo in fo athe imitates oN Mes kom 46 11. Frequency of Turbidity Current Flows at Various Locations in fhe TOTO! : 5.86 98S OM Pe eee ide Moe Tet ine ene’ adele 47 12 Areas of High (>1.0 psi) and Low Cohesion inthe TOTO ........ 30 13 Distribution of Surface Sediment Organic Carbon Content (%) ..... Ol IZo (lets OF Saife’s Resisicm Durie) Comers lowerlings 5665660000006 59 TABLES | Particle size analyses of near-flank sediments .... . oat cttet se) Lo. Il Near-flank sediment density, water content, void ratio, andl porosihy, Ga ay seen cetiae ote oh egmeeate cuter tel, Garteh Uses. To BAe eee Ill Particle size analyses of axial sediments . . . . 2. 2. «© «e+ eee ee 29 IV Axial sediment density, water content, void ratio, and porosity .... . 34 V Particle size analyses of cul-de-sac sediments .....-.++-+-se-e-se Al VI Cul-de=sac sediment density, water content, void ratio, and DOTOSItys coer 64 Extra quick > 98.4 Wet Unit Weight (gm/cc): The bulk density of the sediment measured to the nearest tenth by means of wet weight per known volume of sediment. Water Content (%): Ratio in percent of the weight of water to the weight of the dried solid particles in a given sediment mass. Void Ratio (e): The ratio between the volume of voids (V.) and the volume of solids V Vv e = — Vs Color: Color of sediment is based on the Geological Society of America Rock- Color Chart. Sediment Grain Size: The sediment grain size scale used is the one categorized by the classification set forth in the Wentworth grade scale (Wentworth, 1922) with one modification. The term clay has been replaced by the term lutite because of the mineralogical implications of the former. The range of grade size in millimeters diameter and phi units [o =- logs diameter (millimeters)| is shown below: Particle Particle Diameter Diameter (mm) (phi) Granules 2.0000 to 4.0000 -2 to -l Coarse sand 0.5000 to 2.0000 -l to 1 Medium sand 0.2500 to 0.5000 Il fo 2 Fine sand 0.0625 to 0.2500 2 tie Zl Silt 0.0039 to 0.0625 Ato 8 Lutite < 0.0039 > 8 SEDIMENTS General On the basis of lithology and physical properties, the sediments collected from the TOTO are divided into 3 geographic categories; 1) near flank, 2) axial, and 3) cul-de-sac (Fig 6). The bottom sediments in the TOTO display properties and relationships distinctive of these areas in the channel, but, gradational transitions from one type sediment to the other is present, and combinations of various types exist. Irrespective of lithological and physical variations in the sediments, both calcium carbonate content and specific gravity of the solids show no significant variation with depth or location, but are generally uniform throughout the bottom and vary between narrow margins. Ofa total of 315 core subsamples analyzed for calcium carbonate, the maximum value obtained was 100 percent, the minimum 82 percent, and the average 94 percent. Specific gravity determinations were run on 32 subsamples from representative cores, and the values obtained ranged from 2.68 to 2.86 with an average of 2.79. The results of a semiquantitative spectrochemical analysis by the University of Miami (1958) are given below, and may be taken to represent (+ 20 percent) other possible elements and compounds present in the TOTO sediments where CaCO3 does not comprize the entire sample. PLEPEEEBEELUEG: Vie AA PULAU M EEE Ge PUAAEMUL EE MCL th GUEBPEGUEUEL EE CATA RATA ATA CLL VA CY IIE CLUDE EEE DRYALLALAGEELLEE OAL LAA AAS LD CUGCUGEE ELD CALA, LEOUMELEEEUE CLUEUEGUPUMEECECEE Et i GCOPEECHEEE EE. ILE UEEEEEL EEL bb G. MG MMEOLELEME CELE GUUULMEEDUEE GB L447 ALL (| AXIAL [7777 7 CAGE WAG a= ae EEE OF 5 LOUUEEUMEBEELEEE GE LE SASSAASSSSAASSLSALAS NE CUGUEUEEEEEE DEE Eb AAG GUULEEMEELEMEMELE bb? YOUU EEEMUEE EE OEE EEE WO CAAEEECEUEEUEEEG EEL EG Ge GUOUEEEEEEEU ELE EU th GVO EEEOMEEEEE EG LG LF COU UYPEYEELUEE Eb LB COMME EEUULE E bb Gi? \AAEEUDEECREEED EY GE GP LAL EEELEELEEEEEE EL UME ed Lt bh bE CACBPEEEEUEEEEGE AB CUBUEEUEE EEE E ABO WAL LEE CEMUEUE EL Ns NEAR FLANK MAL LLGPEAEE EE Ae PLL LELECLEEEE WO ACALEEEEGELED CELLET OL CLEEOCLELELEE COL NY OEUEDOE: A @ ALAA CGE LO GLEE CDRA ALLELE AN AAG CAD PL EOLA E EECLEECE YG OO CULAEEL EE a OMA bo bULUELE LE CLL ROY OE CLG Ub i COOL CUL-DE-SAC FIGURE 6 AREAL DISTRIBUTION OF SEDIMENT TYPES IN THE TOTO 14 Material Amount (%) CaCO3 85.000 SiO? 7.000 oa = a A Fe2O3 0.600 MgO 0.300 Ti 0.005 K Trace Sr Trace V Trace Zn Trace Except for the CaCO3 content and the specific gravity which tend to remain constant in the sediments, other properties show a variation in magnitude which is generally dependent upon the area from which the sediment sample was obtained. These variations will be discussed below under the appropriate sedimentary category. Near-flank Sediments Sediments of the near-flank category are represented by the following samples: 625] 62-23 62537, 62-4 62-24 62-38 62-6 62525 62-39 62-9 62-26 O2S)/ 62-10 62-28 62-58 62-14 62532 Ollie O2ei5 2533 |) O>|9) 62-34 61-10 62-20 62-35 61-18 62-2] 62-36 An examination of Figure 4 shows that these samples are all located on the flanks or walls bounding the TOTO and were collected from water depths between 250 and 1,243 meters. Sediment color in the near-flank area is decidedly darker compared to other areas in the TOTO and is dominantly yellowish gray (5Y7/ 2) grading to a lighter greenish gray (SGY8/1). (Geological Society of America Rock -Color Chart code). The most striking property exhibited by these cores, except for a few from the southern flank of the cul-de-sac, is the smooth, even color and texture with depth in the sediment. Figure 7 presents a longitudinal cross section of selected near- flank cores, and, from this, the general homogenuity of particle grain size and sediment color is evident. 15 Cores 62-37 and 62-57 show a very sharp break in color at various depths in the core. Core 62-37 changes abruptly from a yellowish gray clayey silt to a pure white clayey silt with no apparent change in grain size or constituents. The white area is underlain by material similar to that above it, and the pattern is repeated within a few centimeters depth. The white area is far more cohesive than the material above and below it. Cores 62-36, 62-38, and 62-39 are similar in most respects to the normal near- flank sediments, except for one or two zones of relatively coarse particles intermixed and separated from each other by finer material. These zones do not resemble layers which might have originated through turbidity current deposition but appear more like the result of sand "falls"; however, reworking of the material by organisms may have destroyed the original bedding, although other evidence of such activity is lacking. Sample 62-6, a grab sample, consisted of very coarse reef detritus, apparently from the nearby Andros Island barrier reef, and displayed the coarsest grained material of any taken from the channel. Particle Size: Table 1 gives quartiles, median diameter, quartile deviation (QDgJ and skewness (Skq¢) values of subsamples from cores and grab samples in the near-flank area. Some general relationships are given below: Qig and Q3¢ = Ist and 3rd quartiles, respectively, Mdg = Median diameter, QD¢ = (Q3 - Ql), and Skag = (QI Q3 - 2Md). NIHN|= In all samples (except three) the median diameter is within the range of silts, and, as well be shown later, this is by far the predominant particle size of the bottom sediments throughout the channel. The average grain-size distribution of near-flank sediments is 14 percent sand, 61 percent silt, and 25 percent lutite. The quartile deviation (QD) is a measure of the average spread of points around the median (sorting), and when perfect sorting is obtained QD is equal to zero. The sorting values in Table 1 show an almost equal number of poorly-sorted and normally- sorted samples. This is in sharp contrast to Illing (1954), who found sorting values for the adjacent bank sediments to be so uniformly low that it was necessary to break down the well-sorted category into smaller increments in order for the values to be meaningful. Quartile skewness (Skqé) is a measure of the symmetry or asymmetry of the curve of particle-size distribution. If the curve is perfectly symmetrical, then Skqé is equal to zero. If the spread of particle size is greater on the fine side (positive values) of the median diameter, then Skqé is positive, or if greater on the coarse side, then the value is negative. The greater spread of particle sizes on the fine side of the median diameter in these sediments shows the dominance of fine material in the near-flank area and may be the result of sediment winnowing by waves and currents on the shallow banks adja- cent to and above this area. Water movement on the bank may stir up the bottom ma- terial and allow the coarser grains to resettle while maintaining the finer debris in suspension. The fine material is then carried to the edge of the bank, and, due toa DEPTH IN CORE (CM) g cM DEPTH IN CORE 90 110 36 30 ThowisH Guay 62-14 62-19 veowisy 62-14 FIGURE 62-20 62-21 vhiow cuay 62-34 62-57 YELLOWISH onay TT THLOWISH Chay 62-25 62-36 62.37 62-38 62-32 LONGITUDINAL CROSS SECTION OF NEAR-FLANK CORES 17 62-58 YELLOWISH onay LEGEND STATION NUMBER MEDIAN PARTICLE _ DIAMETER (MICRONS) SEDIMENT COLOR ————— COARSE-GRAINED ZONE 61-1 61-9 61-10 100 DEPTH IN CORE (CM) DEPTH IN CORE (CM) Ean a 1h. 1 iy 4 a ee i thi i 4 } ; P re ae oe decrease in current velocity over the deep channel, the material settles through the water column and is deposited in the near-flank area. Core No. 62-1 62-4 62-6 62-9 62-10 62-14 62-15 62-19 62-20 62-21 62-24 62-25 62-28 62-32 62-33 Particle size analyses of near-flank sediments Depth in Core (cm) 94 Grab BR FF SH HPF AHS HAH AGH FWOHW WKH HH HHO HWW Ann an ang arf aa anmn an Nan an ONG aAwWs TABLE | Q3¥ 7.03 Oo (oo) No Wool bao pe) Ww N N ON DO NON NOD —-OWO NN®D NOOO NN O'0SO OOO [ee) Os ON—- —$O WNN —NH ANN —H— NNN 37 18 523 .62 5) 24 62 -43 98 42 00 -66 03 63 LX) 98 90 5// 63 73 .02 29, .06 36 oo — = oO Clo (Oo oO —" Oo — eo | Olol— oo — oO Core No. 62-34 62-35 62-36 62-37 62-38 62-39 61-10 61-18 TABLE | Particle size analyses of near-flank sediments (Cont'd) Depth in Core (cm) Qlg Md Q3¢ 3 5.45 ZNO ORS2 68 5.45 7.60 10.63 146 7.54 8.70 9.86 Grab 558 6.60 9.00 3 505 6.25 Cro, 34 4,30 9525) To) 72 S\o/4l/ 7.00 Pod 3 5508) Uo) 9.18 35 4.00 6.20 P10 Oy S05) 6.70 DoT 5 4.98 Graz 8.22 35 5.04 6.70 9.10 4 4,98 6.50 8.90 1] 3088 5,52) 10.40 48 Madd 6.76 0.522 90 5.55 7.85 10.38 10 6.83 Sro2 10.25 74 4,26 6.00 11.20 145 4.93 oJ?) 8.85 3 5 6.56 9.20 91 4,74 6.06 8.85 3 512 S5oV8 9.00 47 4,83 5.95 9.50 57 4.99 6.80 ORS7 5 4,56 Oe II7/ 8.43 15 4.62 Sn) oS 48 4.7) Socks} 7/552) Sy So IZ Gril 10.20 5 5.05 6.00 8.44 25 5.24 O74) 9.00 5 S58) 6.68 8.91 45 5.44 6.76 9.26 5 5.42 7.02 10.78 82 6.78 8.52 WileZe 20 QD¢g 94 oO 16 84 nO ./8 .24 5 Hi 5S) no2 92 .03 96 a2 38 4] all 47 96 .05 07 94 34 .69 94 ofall 43 54 ./0 .88 .70 91 68 90 ND eS SS eS NS NO NNO ND HOH NNW Nm NNO NOMS AH ANA Skag O229, 0.44 0.00 leWZ 0.56 0.83 OF Os U7 0.35 0.68 0.38 0.37 0.44 1.63 0.39 0.12 0.02 73 5 Ie 0.59 0.75 1.08 ey22. 0.88 0.32 1.14 0.76 od 0.74 0.83 0.53 0.59 1.08 0.76 Constituents: All material greater than 250 microns in diameter was separated from each subsample used for size analysis and examined under a binocular microscope. This procedure was followed to determine the nature and the source of the sedimentary material and to estimate grossly the abundance of various components present. Near-flank sand-sized particles are composed predominantly of skeletal and non- skeletal calcium carbonate. The skeletal debris is represented by the tests of plank- tonic and benthonic foraminifera, pteropods, ostracods, calcareous algae, molluscs, coral debris, alcynarian spicules, and echnoid spines and plates. Nonskeletal parti- cles are oolites, casts of foraminifera, and oolith-like particles described by IIling (1954) as grains of aragonite matrix. In addition to the calcareous material, small amounts of siliceous sponge spicules were encountered. In the majority of the near-flank cores fibrous plant-like material is present and serves to aggregate numerous fine particles which ordinarily would fall into a smaller particle-size category. No visual or mineralogical examination of the material comprising the silt and lutite fraction was made; however, X-ray analysis by Rusnak and Nesteroff (1962) revealed that the finer fraction becomes more calcitic with decreasing grain size, and the less than 2 micron fraction contains about equal amounts of calcite and aragonite. Placement of this sediment into one of the existing deep-sea sediment classifica- tions after Revelle (1944) or Olausson (1961) is unwarrented as these categorizing schemes were originated for the constituents normally found in deep-sea areas away from rich sources of shallow-water material. Likewise, classification of the sediment under one of the many schemes for shallow-water sediments is not feasible due to the large quantity of deep-sea components. Consequently, the bottom material from the near-flank area will be referred to as calcareous ooze, and no generic implications are attached. Organic Carbon: Organic carbon content of the top centimeter of the near-flank sediments is high relative to samples from the central area of the TOTO. The lowest value of organic carbon content from near-flank samples was 0.21 percent, the highest 2.48 percent, and the average 1.22 percent. These values are lower than those ob- tained on the shallow banks surrounding the channels where values range from 3 to 6 percent organic content (Trask, 1955) but are higher than the average deep-sea sedi- ments which contain 0.3 to 1.5 percent total organic matter (Schott, in Trask, 1955). A strong odor of H»S was noticeable from all the near-flank cores. Over half of the cores from this group were measured for hydrogen ion concentration (pH) at the top and bottom immediately after being brought aboard ship, and in all instances the pH was between 6.0 and 7.2. In contrast, cores from the central or axial area show litho- logic features indicative of oxidizing rather than reducing conditions. Mass Physical Properties: Measurements of sediment density, water content, void ratio, and porosity were made, and the results are presented in Table Il. In some instances, cores suitable for particle size analysis were not considered suitable for mass 21 physical properties analyses; consequently, the data for a particular core may appear under one heading and not the other. TABLE II Near-flank sediment density, water content, void ratio, and porosity Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 62-1 8 1.88 89.10 1.60 61.53 737/, 99.81 47 1.54 82.62 2.30 69.69 7\ Zl oS 94 1.60 68.86 1.94 65.98 62-10 14 5 G2 .22 Poof) 69.41 42 61.34 73 1.63 68.08 1.87 65.16 108 74.06 138 16) 74.06 eZ 63.76 62-15 15 les Doll? 1.46 59.34 43 55.40 VS) 1.80 50.98 1682 57.08 98 So /x) 121 Vod7/ 46.51 e380 DOno2 62-19 1] 1.58 69.90 1eQY 66.55 30 T3604} 72 1 ay 71.62 Lo? 66.55 88 90.44 118 1.63 62.28 lov 63.89 62-20 3] 1.66 58.94 1.66 62.40 56 61.62 ne, 1.63 64.14 1.80 64.28 105 T2073 130 1.60 lad 6&9 66.55 62-21 18 1.60 67.82 leo2 OS) //) 48 66.75 78 1.64 63.33 lov 63.89 100 61.45 136 1.66 68.71 lcs 64.66 62-24 3 163 66.77 1.84 64.78 16 65.12 28 1.61 63.49 183 64.66 39 S578} 52 1.63 61.41 le6 63.76 22 TABLE II Near-flank sediment density, water content, void ratio, and porosity (Cont'd) Core No. 62-28 62-37 62-38 62-39 62-57 62-58 OY 61-18 Depth in Core (cm) 13 44 70 114 Wet Unit Weight (gm/cc) 1.64 23 Water Content (%) 63.30 60.98 61.08 60.23 66.01 IZ 08) 74.62 38.80 88.69 46.69 74.05 83.34 93.24 65.85 65.90 66.04 Void Ratio lov Wo¥Z 1.84 Ze. 1.37 Porosity (%) 63.89 63.23 64.78 Toll 57.80 66.44 64.66 Density measurements were obtained by inserting a chrome cylinder of known weight and volume into the core and extruding the core from the liner for a distance equal to the length of the cylinder. After trimming and wiping the exterior and ends of the cylinder clean of excess sediment, the weight of the sediment and its container were obtained. This procedure measured the wet unit weight of the sedimentary material. Water content of the sediment was measured by longitudinally splitting the increment used in the density measurement, extracting a sufficient quantity of the sediment from the center of the increment, weighing the sample immediately, drying at 105°C, and reweighing. The water content was calculated by the equation: Water Content, w(%), = (Wet Weight - Dry Weight) Dry Weight % Ue The void ratio was determined by the equation: , Vy Void Ratio, e, = — Vs _ Dry Bulk Density where VW = Specific Gravity and Vey = | TiN es Porosity of the sediment was obtained by the equation: V ° v e Porosity (%) = Teal Valuas NWO) 5 eo The values presented in Table II show approximately 70 percent of the cores in the near-flank area decreasing in water content, void ratio, and porosity with depth in the sediment and increasing in density with depth. However, particle grain size is strikingly similar through the sediment, and the mineralogical composition is almost wholly CaCO3. The increase in density with depth in the sediment is most likely the result of compaction and consequent loss of interstitial water. Below are the maximum, minimum, and average values of the properties tabulated in Table II: Property Maximum Minimum Average Wet Unit Weight 1.80 1.34 1.62 Water Content 129.8 47.4 70.4 Void Ratio 2.98 1.80) legs Porosity Hl o® 56.5 Gar 24 Axial Sediments Bottom samples representing axial sediments are from the relatively flat area located at the base of the flanks of the channel in the narrow, elongated portion of the TOTO north of the cul-de-sac (Fig 6). Compared to near-flank sediments, axial sediments are characterized by lighter, more varied color, a wider range of particle grain size, higher density, lower water and organic carbon content, and many abrupt changes in lithology with depth in the sediment. Cores 62-60 through 62-63, which are from Northeast Providence Channel, are included herein because of their similarity to axial sediments. Cores included within the axial category are: 6252. 62522 62-50 61-6 62-3 62=23 62-51 Ollis7i 62-5 62527, 62-52 61-8 62-7 62-29 62-60 61-21 62-8 62-30 62-61 61-22 62-13 62-31 62-62 62-16 62-47 62-63 62517 62-48 61-2 62-18 62-49 61-4 Samples from the central reaches of the channel show frequent, abrupt changes in sediment color with depth in the core (Fig 8). Colors range from dark yellowish brown (10YR6/ 6) to a pure white (N9), and, in the majority of instances, the color changes do not appear related to a change in any Bantieolee sedimentary property. Colors in the orange hue are prevalent and are believed to represent oxidation of the ferrous ions present in the sediment. As opposed to the near~flank sediments, no H2S odor was de- tected in the axial sediments, and the few pH measurements taken were always in excess of 7.0. Superimposed on the colors recorded in Figure 8 are occasional bluish-black mottles and streaks throughout the majority of the cores which are probably due to de- composition of plant debris incorporated in the sediment. Plate | compares a typical core from the axial and near-flank area. Almost all axial cores contain relatively coarse-grained layers oriented normal to the core axis. These layers are in sharp contrast with the underlying material, grade gradually into the overlying material, and show a gradation from coarse to fine sedi- ments upward in the core. Plate II is an example of this type deposit, and core 61=21 in Figure 8 shows the decrease in median grain size diameter upwards in one of the graded beds. In a few of the cores the coarse layers are only slightly coarser than the surrounding material, and, as a result, ina freshly split core the upper portion of the graded sequences are difficult to recognize. However, on drying, the decrease in particle size upwards becomes conspicuous, and, as discussed by Ericson et al (1961), the shrinkage of such sediment on drying is proportional to the ratio of lutite particles to larger grains. In effect, the differential shrinkage of the sediment when thoroughly dry produces a smoothly tapered increment where the base of the sequence (due to less contraction) is wider than the upper portion of the layer where it makes contact with the overlying sediment. 25 Cause of graded bedding similar to that present in the TOTO sediments is discussed by Kuenen (1953) and Kuenen and Menard (1952), and lithologic features of this nature are suspected to be the result of deposition by turbidity currents of high density. Such processes are of short temporal duration, and the velocity attained by the turbid flow is dependent upon the density of the flow and the slope gradient over which it is passing. As the turbidity current decreases in velocity, the coarser and gradually the finer and finer particles are deposited; hence, vertical grading results. Graded beds of this nature and the suspected mode of deposition have been designated by Kuenen (1957) as "turbidites," and this nomenclature will be used herein. Turbidites do not generally occur at the same depth level in all cores, or are they of the same vertical thickness. Since all cores except those preceded by the number 61 were taken with the same instrument and following the same method, differentially induced compaction through variation in sampling procedure or instrument type is not suspected for the lack of correlation between turbidites from one core to another. To account for the lack of horizontal continuity, extensive sheet-like turbidity currents are not theorized. Instead, localized turbidity flows within the many gullies trending at right angles to the bank edges and incising the channel walls are more likely. High velocity restricted flows of this nature are discussed by Ericson et al (1961), and such localized transporting phenomena which have originated through slumping on the upper walls or bank edges best explain the discontinuous, variable distribution of the turbidites. Rusnak and Nesteroff (1962) discussed the TOTO turbidites in detail and concluded that 70 to 90 percent of the channel deposits have been produced by turbidity currents. It is stated in a Technical Report by the University of Miami (1958) that density (turbidity) currents created by instability of sediments on the edge of the banks may contribute material to the floor of the TOTO. Many of the cores in the near-flank area were collected from within the gullies and displayed no features suggestive of turbidity current deposition. Consequently, it is expected that the turbidity currents originating on the banks above the near-flank area flow with sufficient velocity down- slope to prohibit deposition in this area. On the other hand, turbidity flows may be originating near the base of the flanks and flowing outward into the channel, thereby accounting for the absence of turbidities in the near-flank sediments. Particle Size: Silt-sized particles are the dominant size fraction in the axial sediments; however, compared to the near-flank area, there is a decrease in percentage of silts, a slight increase in sands (generally explained by the coarse turbidite layers ae ee and a fairly large increase in lutites (Table III). Average particle size distri- ution in the axial area is 17 percent sand, 49 percent silt, and 34 percent lutite. Sorting values are higher in these sediments as a result of an increase in sand and lutite. Over 75 percent of the samples analyzed are poorly sorted, and the bulk of the remaining samples show average sorting. Sorting values in the turbidites are generally high. Rusnak and Nesteroff (1962) discussed sorting coefficients and ex- plained the poor sorting in the turbidites as relating to the small size of the channel which limits the distance over which sorting can occur and to the hydraulic behavior of the variety of biological debris in the turbidity current flow. 26 DEPTH IN CORE (CM) DEPTH IN CORE (CM) 100 100 20 DARE TELOW Ces (1 Gareragy omar 62-3 62-7 very Pat mur 62-13 THLOWISH onaY CAAYGH YELOW very PALE ue 62-47 62-17 VERY PALE omnot ERY UGH caay very PALE MANGE 62-48 62-49 VERY PALE on) FIGURE 8 62-18 62-27 Veny PALE GRAYISH TRUOWISH ORANGE mown TELOWISH caay very PAUL MANGE 62-50 62-51 VERY PALE OFANGE GRAY YELLOW VERY PALE OFANoE 62-29 TEIOW Gear GRAY ORANGE YELLOWISH onay 62-60 YEUOWISH ORANGE GAY ORANGE LONGITUDINAL CROSS SECTION 27 62-30 62-31 GRAYSH OANGE YELOWISH YEUOWISH cmay YELLOWISH veRy PALE MANGE 62-63 Very PALE UE WHITE UE wniTe LEGEND STATION NUMBER — MEDIAN PARTICLE _ DIAMETER (MICRONS) SEDIMENT COLOR —————>— COARSE-GRAINED ZONE - OF AXIAL CORES 62-23 62-52 YELOwIsH YELOWISH GAY Geay 61-4 61-6 TIGHT GRAY Very Pale Oeance 62-61 62-62 YEOWwISH Gay VERY PALE OFANGE VERY rae CHANGE 61-7 61-8 VERY PALE MANGE Very PALE MANE 990 220 15 5 64 21 61-21 61-22 VERY PALE MANE 120 130 140 150 160 100 DEPTH IN CORE (CM) DEPTH IN CORE (CM) te i wow wn thy i tea We gat? ute uF ey (ae i ti i ' ‘ in iin : Ps penne ste ss il A ie fy Core No. 62-2 62-3 62-5 62-7 62-8 62-13 62-16 62-17 TABLE III Particle size analyses of axial sediments Depth in Core (cm) Qi¢g Mdg Q3¢ QD¢g 27 3.94 5.68 8.09 2.08 84 O23 792. We? 3.38 136 5.74 8.90 12688 3.30 5 6.58 8.24 10.45 1.94 43 5.01 7.64 Mleov, Dos) 65 5.43 8.30 11.67 SoZ 120 7.53 8.45 11.46 2.87 2 Vs) Dor, 4.45 liso 8 3.43 4,93 6.90 1.24 12 SEoZ SoZ 7.48 2.08 5 S58) 7.08 10.00 2.34 32 ilkZ I Pol? 2.04 44 4,28 Hoe) DY) 2.66 88 5.04 6.84 10.00 2.48 117 5.58 9.00 11.80 Soll 140 Zo, 5.95 9.44 S628) 154 4.83 7.20 9.94 2ROO 5 3.77 4.89 6.75 1.49 14 3.96 5.24 7.62 1.83 42 4.05 5.30 8.05 2.00 67 Sel S72 Soil 0.96 74 4.86 6.14 10.02 2.58 9 4.62 5.40 Ve\\Z/ ozs! 40 850) 4.12 S)ev/l 1.20 70 4.94 7.00 10.49 2S 83 3.44 205 8.25 2.41 134 5.02 6.95 10.57 xe Ths) 2 5.40 Teor 10.90 57S) 7 67S 8.13 10.91 2.58 80 5.98 8.56 11.20 Zor 156 6.41 DoZAll We 2.79 5 55 7/0) Srulte 11.01 2.66 76 Sa 75) E20 15.85 5.28 103 3.46 5.40 9.42 Packs) 29 —— © OO0CO Core No. 62-18 62-23 2527, 62-29 62-30 62-31 62-47 62-48 62-49 Particle size analyses of axial sediments (Cont'd) Depth in Core (cm) Qlig 3 6.00 46 5.66 76 a205 94 5.45 109 5.08 | 5.64 3 o200 1] So Shs) 21 5582 36 Oeil 5) Dol! 45 3.48 1s eae 108 4.79 5 S)o223} 1 4,22 38 4.79 99 2.66 106 So) 129 elie, 11 6.00 66 2.54 101 SoZ 120 585 10 5.80 78 4.98 149 Hoos) 3 4.43 19 5) 57/ 3 4.09 51 4.00 91 1.46 101 5.00 5 4.42 10 4.5] 30 TABLE III Mdo/ O—aoun anoods® 101 00 0030 © OO NH NWO ND —- RONDO ANOaG—N © WO CORO OUNAnO—W Oo 00 .O — 0 OMOIan NO ONO GOWOAOMO NOWOON NNOD NNONN COON CO 0 (ee) On OfRNW SO NNOM Oo On on GW © Oo Q3¢ 10.94 Noe Mol? 10.95 2075 Polke 9.00 10.86 10.99 10.05 7599 9.82 10.75 Bae) 11.45 6.00 10.10 5.43 11.58 10.56 10.15 I@ WZ 11.30 Mod 10.73 11.81 13.55 9.50 10.86 QD¢ -47 .06 nO oS of!) nO oD .64 84 oS/ 42 oI 76 NY oll 89 66 39 90 69 .07 Te, ./6 -80 47 42 oll 204 .65 .03 80 mle 45 NMMMDHY HMM BWHY NNWN NNAWNHNOW WNHWN NNNAN NWWWN _ 08 TABLE III Particle size analyses of axial sediments (Cont'd) Core Depth in Core No. (cm) Qlg Md¢ Q3¢ 62-50C 4 6.00 8.80 11.67 44 Uo 11.20 IDolS 62-51 3 DOS 7.74 10.59 25) 5.56 8.31 11.60 56 SoZ 7.48 9.86 62-52A 3 5.68 7.86 10.00 8 5.43 Uo 10.55 52 S)ocks) S25) 10.83 76 4,99 Oo) 9.58 62-60 5 4.91 6.54 9.44 42 5.00 6.08 7.14 62-61 6 3.55 5.05 Lod> 26 4.06 5.60 9.18 68 3.78 5.26 oI? 93 3.43 5.25 8.78 133 5.35 8.35 13.87 62-62 20 5.36 7.30 11.08 73 5.14 8.25 12.45 138 5.42 7.90 11.64 62-63 3 5.01 6.70 10.05 32 5.50 9.23 14.10 61-2 5 So NA, 3.73 5.88 15 2.66 4.07 6.65 25 2.90 4.56 7.94 61-4 5 5.42 7.13 ery, 15 5.65 7.49 9.66 75) 6.07 7.80 10.67 32 5.47 7.28 10.75 61-6 5 SoU 7.02 10.02 25 5.57 UNO 10.58 35 5.80 7.62 11.40 45 4.84 6.33 10.50 61-7 5 6.06 Los? 9.78 45 0.15 Zeal, 4.32 50 = 2S SH o7/l 5.41 3] —$OW Wsoseoem Our-a amw@d ~T®OdM AMO NWAODONWN OB CS RS ONW fBOWOA WNN®O @®OoO NW WON ADAWNO —k BRON ~—H~Nm NNNN NNMNNM NNT FN WWHN EFNNNNM AND NN TABLE III Particle size analyses of axial sediments (Cont'd) Core Depth in Core No. (cm) Qlg Mdg Q3¢ QDYg Skqg¢ 61-8 Fs) 6.89 8.52 Uolll AW 0.48 25 S07 6.55 11.55 Sol 1.74 65 5222 7.30 10.73 2.76 0.68 61-21 3 S658) 4.74 SoS Zell 680) 10 4.30 6.46 8.60 Ao IS) 0.01 15 S55) 6.01 8.93 2.49 0.03 29 3.54 6.09 8.64 DoS 0.00 40 4.90 7.31 OP 2.41 0.00 50 2.50 509) 8.88 SoM 0.00 55 0.28 So 87 7.45 SoS) 0.00 59 5 27/ 7.63 9.99 2.36 0.00 96 Doo Wood? i512 3.81 less 61-22B 4 4,99 6.20 9.00 2.01 0.80 12 2226 6.85 10,52 2ROW/, 1.08 22 5605) Voll 11.74 2.90 1.08 30 O89) 8.43 12.30 270 0.92 Skewness values are predominantly positive; however, proportionally more samples are skewed in a negative direction, and the skewness values more closely approach zero than near-flank sediments. Constituents: Ungraded sections of the axial cores are dominated by planktonic foraminifera and pteropods; although, reef-derived material is present to some degree. The turbidites are composed in equal part of pelagic and reef-derived materials. Pteropods present in the graded beds are dominated by the genera Creseis (the tapered needlelike form observable in Plate II). Core 62-8 contained a number of both clear and smoky angular quartz particles which were not encountered in any other core. Source area of the quartz is unknown but could be explained through transport by winds from a terrestrial continental source; although, wider distribution of the anomalous particles would then be expected. Siganic Carbon: Organic carbon content in the axial cores averages 0.44 per- cent and ts about percent lower than the average for near-flank sediments. The majority of cores show a sharp decrease in organic content with depth. The maximum value encountered was only 1.08 percent. Vasicek (in Ericson et al, 1961) advanced the theory that turbidity currents rushing down slope should sweep up or carry along much living or dead matter which would be deposited with the finer fraction. Previously Ericson et al (1952) reported the common 32 occurrence of plant debris and hydrotroilite (an amorphous monosulfide of iron FeS.H»O) in ungraded beds within cores from the North Atlantic. However, it can be shown that no evidence of organic entrapment fs present in the graded portions of axial sediments, and organic carbon values from turbidites in this area follow the general decrease in organic matter with depth found throughout the sediment. Mass Physical Properties: Axial cores display relationships between physical properties with depth in the sediment which are similar to the near-flank group. Sediment density generally increases with depth; conversely, water content, void ratio, and porosity values generally decrease with depth. Table IV shows the sediment from this area to be slightly denser and considerably lower in water content, void ratio, and porosity than near-flank sediments. In addi- tion, the axial group shows less magnitude of variation of these values around the mean. Below are the maximum, minimum, and average values of the properties tabulated in Table IV: Property Maximum Minimum Average Wet Unit Weight 1.76 1.53 1.66 Water Content 89.1 44.5 66.9 Void Ratio 2.58 loo lov Porosity Tae | 56.3 63.0 Cul-de-sac Sediments Bottom samples representing cul-de-sac sediments are from the flat, central area of the cul-de-sac and the flanks bounding the northern and northeastern portion of this area (Fig 6). Cores from the central portion of the cul-de-sac are differentiated from near-flank and axial cores by more frequent turbidites, poorer sorting, lower density, higher water and organic carbon content, a high void ratio, and a higher porosity. Cores included in this group are: 62-40 62-45 62-56 62-4] 62-46 2557, 62-42 62-53 61-11 62-43 62-54 OZ 62-44 62-55 61-16 Cores 62-45, 62-46, 62-44, 62-53, and 62-55 are arbitrarily included in the cul-de-sac group because of variations in color and the presence of a few recogniz~ able turbidites; however, these cores are very similar to near-flank cores and the difference between the two is slight. 33 TABLE IV Axial sediment density, water content, void ratio, and porosity Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 6252 Di, 1.71 54.90 1.62 60.31 60 94.33 85 1.64 63.94 1.78 64.02 112 S95 1172 137 1.66 Soy 1.68 62.68 62-3 20 1.69 62.13 1.67 62.54 46 58.21 65 1.66 58.54 1.65 62.26 93 58.26 120 ter 57.84 1.63 Glia 62-7 44 1.67 59.24 1.65 62.26 67 Uo) 88 lod S35115 \oa7 61.08 112 59.35 147 1.65 63.19 1.76 63.76 62-8 14 1S 59.24 1.68 62.68 26 72.23 42 1.64 B35 1S 1.70 62.96 55 59.35 74 1.64 63.19 1.76 63.76 C25 9 1.64 Dole 1.90 65.51 45 66.06 70 Le7Al 53.31 1.49 SDS) 101 64.39 134 egZ 50.68 1.43 58.84 62-16 3 1.63 68.25 Lol87/ 65.15 46 60.05 80 1662 65.29 1.83 64.66 WS 69.35 156 1.66 62-17 28 1.64 69.89 1.88 65.27 52 60.78 76 1.66 58.50 1e05 62.26 93 56.85 113 1.67 55.34 1.58 61.24 34 TABLE IV Axial sediment density, water content, void ratio, and porosity (Cont'd) Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 62-18 3 1.58 82.94 Dee 68.94 28 Vecd® 46 1.66 64.31 lowe 63.76 80 66.25 109 1.66 64.20 167 63.63 62-22 3 687 87.23 Zell 69.78 22 67.25 42 98 76.77 22 67.94 61 69.92 78 eer 48.36 1.47 e851 62-27 16 1.68 S55 24/ oH 61.08 32 69.62 56 1.68 53.54 1.54 60.62 90 S857 108 1.73 54.14 1.48 59.67 62-29 38 loa? 60.61 oo 62.26 7 69.03 104 1.56 77.24 2.16 68.35 129 167 58.02 mosh 61.97 62-30 11 1.68 WGs8 2.58 72.06 44 26.81 66 1.70 60.21 1.62 61.83 93 70.81 120 169, 61.24 | 65 62.26 62-31 10 1.60 67.90 1a?) 65.63 45 72202 78 1.70 56.22 158) 60.78 123 S858 149 1.74 49.04 1.38 57.98 62-47 3 1505 Oileo2 lev 63.36 62-48 3 1.74 Ole loll 60.15 olf 50.54 51 1.74 51.88 29, 56.33 76 60.65 101 oS7/ 54.82 oll 67.84 62-49 3 167 48.15 odd 57.44 35 TABLE IV Axial sediment density, water content, void ratio, and porosity (Cont'd) Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 62-50 3 1.58 89.17 Doss 69.96 24 62.86 44 1.64 64.75 1.79 64.14 62-51B 3 1.64 72.06 1.92 6557/5 25 1.05 ODIs 1.79 64.15 56 1.68 54.74 1.56 60.93 62=52A 3 11 oS 87.56 2.28 69.51 31 68.38 52 1.68 59.10 lees 61.97 73 W678 97 il o74 49.19 lok? B35) 62-60 16 1.70 56.71 1154 60.93 29 55.02 A] 1 o70 61.20 1.64 62.12 64 59.29 82 locZ 5x), 5/ 1.48 59.67 62-61 6 1.67 60.18 | 67 62.54 38 By Z| 68 odZ 55), ISI 60.15 100 55) 727 133 1.70 55.75 1.80 64.28 62-62 9 1.69 62.76 1.68 62.68 44 56.06 73 1.65 56.86 1.65 62.26 105 55) ,27/ 138 1005) 59.74 1.69 62.82 62-63 5) 1.64 75.41 1.98 66.44 17 59.12 32 1.66 61.75 1.71 63.09 61=2 6 1.70 60.90 1.63 61.97 15 1.68 Ol 45) 1.c@7 62.54 22 58.79 61-4 5 1.62 70.33 E92 65.75 1 1.68 61.87 1.68 62.68 25 eS 80.76 DOD 67.21 36 TABLE IV Axial sediment density, water content, void ratio, and porosity (Cont'd) Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 61-6 5) eer 62.05 1.70 62.96 16 DOy2)) 25) 05 63.58 oH 67.76 35 1608 65.08 low? 64.15 44 65.18 61-7 5 1.65 63.00 loz 63.66 25 1.66 63.68 1.74 63.50 35 44,47 61-8 5 eS Soe Deo 10) 22 25 1.66 64.94 1976 67.76 45 1.64 65.67 1.81 64.41 56 1.65 61-21 3 1.69 56.76 oaks 61.24 12 1.66 64.86 1.76 63.76 21 leo? 59.30 62 61.83 29 oy, 62°73 lov 63.54 48 eval 54.67 oS 60.15 56 1.68 55.14 1.56 60.93 68 led 59.06 1.58 61.24 76 a73 SORiZ 1682 60.31 61-22B 4 51.99 11 les 53.83 1.47 555) 20 58.36 29 60.74 Longitudinal cross sections of cul-de-sac cores are presented in Figure 9, and, from this figure, the cores collected from the central, flat reaches of this area can be seen to consist almost in equal part of turbidites and sediments laid down particle- by-particle from the water column. Turbidites in this area accounted for well over 40 percent of the sediment column sampled. In the cul-de-sac it was difficult to ascertain the upper contact of turbidites with the overlying sediment; hence, it is possible that a larger percentage of the sediment column is due to turbidity currents than the data reveals. Many of the cul-de-sac cores gave off a strong H2S odor, and the few pH meas- urements taken were less than 7.0. 37 Excluding zones of turbidite occurrences, cores from throughout the cul=de-sac are similar in texture and color to near-flank cores, and the portion of these cores attrib- utable to pelagic type sedimentation is strikingly similar to the near-flank area. The top 2 or 3 centimeters of almost all cul-de-sac cores show an orange-red hue which is indicative of oxidizing conditions at the surface and which is absent throughout the remainder of the sediment with depth. Core 62-46 contains a very coarse zone unlike a typical turbidite in that the zone shows no grading but consists of a reef detritus where both the top and bottom contact with the enclosing sediment is sharp. This particular sequence is probably the result of sand "falls" over the bank edges rather than turbidity current deposition. Particle Size: Silt is the dominant size fraction in this area as well as the remainder of the TOTO; however, the increase in turbidites compared to the axial area raises the percentage of sand by a slight amount. The graded nature of turbidites is apparent in cores 62-42 and 61-16 (Fig 9) where a decrease in median grain diameter upwards in turbidite zones in the core is observable. The average size distribution of the samples analyzed is 20 percent sand, 29 percent silt, and 51 percent lutite. Poor sorting is prevalent among these sediments, although a few of the samples analyzed from the bottom of the coarser turbidites show almost perfect sorting. Skew- ness values are not much different than the axial sediments in that the majority of samples are positively skewed with a few negative values present (Table V). Constituents: Constituents comprising the cul-de-sac sediments are not unlike the other areas of the channel. Turbidites, however, contain a greater percentage of reef-derived material, and oolites and oolith-like particles constitute a major portion of the reef detritus. Plant debris is more prevalent throughout cul-de-sac sediments than in the axial area, and several turbidites contain thin zones of this fibrous material incorporated into the sequence. Organic Carbon: Organic carbon content of the sediment in this area is the highest encountered in the channel and is probably due to the increase in plant detritus. Surface values of organic carbon are as high as 2.00 percent and decrease in the channel. Mass Physical Properties: Sediments in the cul-de-sac are less dense and contain a higher water content than any sediments in the TOTO, and, in like manner, void ratio and porosity values are also highest. Although the water content shows a de- crease from top to bottom in the cores, there are interruptions in a uniform decrease with depth which are probably due to the large amounts of coarse-grained turbidites present. The turbidites, being more pourous, are capable of holding greater water content than the fine-grained material above and below. As in the other TOTO cores, sediment density generally increases while void ratio and porosity decrease with depth in the sediment. 38 DEPTH IN CORE (CM) 90 100 110 120 130 140 150 160 62-40 62-41 YELLOWISH YELOWISH Gaay ceay iT BiUeGeay YELLOWISH Gray YELLOWISH At BLUEGeay YELLOW (7 BuUEGRAY YELLOWISH 62-42 Very ir Geay YELLOWISH Gray DUE white YELLOWISH Ghar ALUE wie yEUOW Geay very 7 ceay IE TELLOW Gray YELLOWISH Gear Bile whire YELLOW GRAY YEUOW Geay LE WHITE YEUOW GRay YELLOWISH 61-16 62-56 62-59 GRAY OFANGE pine 62-45 TELOW BROWN YELLOW GRAYISH ORANGE 387 YELLOWISH YEWLOWISH 30 7 74726850 54 LEGEND. STATION NUMBER —————>— 62-00 MEDIAN PARTICLE DIAMETER (MICRONS) SEDIMENT COLOR —————_ “tttowrs COARSE-GRAINED ZONE FIGURE 9 LONGITUDINAL CROSS SECTION OF CUL-DE-SAC CORES 39 GRAY ORANGE YELLOWISH 62-55 YELLOWISH GRay YELLOWISH 61-11 GRAY OFANGE TEWOWISH iy MUEGeaY YELLOWISH aay 61-12 GRAY ORANGE UAT mUE TELOWISH | ee 110 140 150 160 DEPTH IN CORE (CM) SESS ASS Are eee y ladies the Fi ceetten Alvin im! | kt Med 6 emit? Core No. 62-40 62-41 62-42 62-43 62-44 62-45 62-46 62-53 62-54 Particle size analysis of cul-de-sac sediments Depth in Core (cm) © Q AWWoa aan OBA HL A ANH ANAWH WWAOWH HARWNH aA SON & LOM WO NO N Oo sO ON Oso Ww NO WWOW MH-OIN NAOM aS ARW AQNOsSOsO Wwonrnann so ROAD AKO ANN SO —Ho WDOAWHKR WNHWOODW NN TABLE V 4| Mdg 94 os) pili, .00 5 1) .65 SV 2g, 98 NOOO NOD NOOOaG NN OOM ONONO AHROHOKRN POOR WHA NPWOOD Ds) Q3y 36 40 30 nom 38 59 allo 62 90 5/4) 56/ 43 96 85 .89 4 87 45 ./0 a9 10 .80 alle) 60 10 5S) wg, 528) 30 BO” 55) 73 .83 10 94 -40 OZ 14.08 _ _ N— Oanwonas NOOoMaMNO OeMNOsOd — ad feed) —OND _— _ —F ed ed —! — — NSO NOOO NOOO OO ND QD¢g SS =D ND) GO) NN) TON NO) =" NIN) (GolC)) NS) (CoyN)Go)— No) = ONG Oe —" NE NE SIN Dw) oO wn x £0) OL ooo bo-coo exo otoko) Onanrs sozw CSN) WES ON] SOON © ONWNW CONWWWH NO Ss SOO Oo] OoF]HO OOo aHoOoC OOOeEOo OOoC— TABLE V Particle size analyses of cul-de-sac sediments (Cont'd) Core Depth in Core No. (cm) Qlg Mdg Q3g QD¢g Skq¢ 62-55 3 5.48 7.44 10.13 Doo) ORS 58 5.69 8.70 12.23 So Zed 0.26 120 5.41 8.00 10.85 ool 0.13 62-56 3 Do 55) 7205 10539 2.42 0.32 47 5.40 8.50 2295) Sod 0.68 66 4,86 TM 11.96 S685 0.44 62-59 5 5.16 6.64 258 (2,780) O72 12 ral, 4,93 9.80 3.81 IO 22 5 7.50 12.95 3.67 los? 33 1.88 3.00 4,96 1.54 0.42 59 4.99 TO 10.85 2.93 0.42 61-11 1 4,85 Sas) Or LoS) lols 21 6.44 770 10.51 2.04 0.52 NAW 5) 5.05 6.11 9.40 2.18 LeilZ 75 6.40 8.07 11.14 Poi 0.70 61-16 5) 5.74 7.09 28 70 0.60 17 Gold 4,86 Pool Neves O72 19 S555) 4,64 7.24 85 0.76 21 2.83 4,16 7.34 2.26 0.92 24 ZO 4.33 Lodll ois 0.86 27 Sho IIS S692 ZollO 1.96 22 29 Zoo SoU) 7.20 2.42 1.00 35 3.08 BolT 6.39 1.64 0.94 4] Dow Uo 20 Qo? 13 0.60 51 So 5.08 LSD 2.02 0.76 The maximum, minimum, and average values of properties presented in Table VI are given below: Property Maximum Minimum Average Wet Unit Weight 5Z 1.40 Loa Moisture Content 13255 38.5 Or Void Ratio Soll 120 Zao \\| Porosity 78.3 54.5 67.0 42 TABLE VI Cul-de-sac sediment density, water content, void ratio, and porosity Wet Unit Water Core Depth in Core Weight Content Void Porosity No. (cm) (gm/cc) (%) Ratio (%) 62-40 26 655) 75.06 Del 68.25 46 OYoPH/ 64 1.62 215) 725 \\3 68.05 106 83.27 129 1.5 88.81 2.47 71.18 62-4] 3 1.40 132.54 3.61 78.30 43 103.53 15 1.58 84.50 73528) 69.23 WW 90.43 14] 1.54 70). 37 2.08 OP 62-42 3 1.45 116.87 Srl 76.01 42 116.89 79 45 87.27 2.60 Lee. Wis 54.73 137 LoS 38.46 20 54.54 62-43 13 1.64 3957/1 lol 63.09 34 84,22 50 1.63 68.78 1.88 65.27 7\ 78.09 99 1.65 O69) 1.69 62.82 62-44 8 loS7 76.43 Dole 68.05 36 T3505 67 ov, V1 o25 Deo) 68.25 104 75.34 13] 1.66 Oll o7/ o)|\ 69.78 62-45 31 Jo@2 62532 No? 64.15 47 69.77 63 lo? 69.85 ey 66.32 Ti 80.43 94 1.60 73.67 2.02 66.88 62-46 8 57.24 26 1.69 S/o ll 1.58 61.24 43 66.24 Sy/ eS 63.82 1.76 63.76 TABLE VI Cul-de-sac sediment density, water content, void ratio, and porosity (Cont'd) Core No. 62-53 62-54 62595 62-56 62-59 61-11 61-12 61-16 Depth in Core (cm) 3 26 52 78 102 19 34 oy, 3 39 58 81 83 120 Wet Unit Weight (gm/cc) ] 1 ] ] 04 66 ol 04 -66 55) 94 74 04 5 71 .65 ol Zs 48 42 49 O58) 293 .93 64 Water Content (%) 2h. OZ 67. 8] 53. 66. 68. OS. NO7e U3 90. Mc 60. 49. 87. 84, 76. Doe 8] 66. Yao 96. 67 64 105. 100. 86. 83. 98. UE 76. 90. 70. 98 85 92 70 24 38 96 86 S)// 18 74 33 87 69 26 35 89 24 ie. 44 12 07 89 51 80 05 43 SV 73 Porosity (%) D\\c 65. Wo 66. 63. 780 68. 58. 70. 68. See .02 64 ie V0 73. 68. 7\ 09 (af 67 67 63 89 35 IS 50 05 28 34 89 Wy 35 09 RATE OF SEDIMENT ACCUMULATION The following discussion is based on radiocarbon dating of the TOTO sediments by Ostlund et al (1962) and data presented by Rusnak and Nesteroff (1962). Figure 10 shows the location of a few of the cores dated and the bulk rate of sediment accumulation at these locations. Figure 11 gives the frequency of turbidity current flows at selected locations. According to Ostlund et al (1962) the rates of sediment accumulation in the TOTO are generally highest on the bank slopes. Those deeper-water cores that show a rela- tively high rate of accumulation are from the narrower sections of the channel, and, therefore, tend to show a thicker accumulation for a given volume of supplied ‘sediment than is found in the broader reaches of the basin. The oldest sediment dated by Ostlund et al (1962) in the TOTO was 26,275 years +570 years and was between 132 to 137 centimeters depth in the core. According to a time scale presented by Ericson et al (1961) this date lies within the last glaciation. Ericson et al (1952) reported that Cretaceous sediments overlain by Pleistocene and Recent sediments were encountered in a core taken at 3,383 meters just north of New Providence Island. The authors accounted for the absent series by turbidity current erosion of exposed Cretaceous sediments at a point not far from the core location. Sediments in the central area of the TOTO, apparently laid down through particle= by-particle deposition, were termed by Rusnak and Nesteroff as pelagic sediments, and they calculated a very slow rate of accumulation for this type sediment. The slow rate of pelagic sediment accumulation becomes apparent by comparing the bulk sediment accumulation per 1,000 years at various locations in Figure 10 against a range of 1.5 to 3.0 centimeters per 1,000 years accumulation attributed to pelagic type sediments. The balance of the sediments not accounted for by particle-by-particle deposition during a 1,000 year period is assigned to turbidity currents. Frequently the turbidites are considerably older than the sediments over which they lie, indicating that an accumulation of reef-derived and pelagic material builds up on the upper slopes of the near-flank area, and, through various causes, is released to flow down slope on top of the material deposited contemporaneously with the buildup of near-flank accumulations. From Figure 10 the rate of sediment accumulation can be seen to diminish north- ward along the channel axis; likewise, frequency of turbidity current occurrence also diminishes in the same direction (Fig 11). Consequently, as the present channel floor continuously slopes in a direction coinciding with decreasing sediment accumulation, it is expected that the slope of the channel floor is in large part a depositional gradient, rather than due primarily to some underlying structural mechanism. 45 @5 CM/1,000 YRS @4-I7 CM/1,000 YRS \ \ \ \ \ | | | | @ 20 CM/1,000 YRS @5 CM/1,000 YRS eee ee = \ 30 CM/1,000 YRS ® SS DATA AND CORE LOCATIONS ARE AFTER ~~ ee RUSNAK AND NESTEROFF (1962). FIGURE 10 RATE OF BULK SEDIMENT ACCUMULATION AT SELECTED LOCATIONS IN THE TOTO 46 1/6,000 YRS 1/10,000 YRS 1/600 YRSN \/6,700 YRS 1/470 YRS @1/3,600 YRS @1/2,500 YRS WHERE TWO FREQUENCIES ARE SHOWN FOR A SINGLE CORE, A DIFFERENT RATE IS EVIDENT BETWEEN THE UPPER AND LOWER SECTIONS OF THE CORE. AFTER RUSNAK, AND NESTEROFF (1962), FIGURE 11 FREQUENCY OF TURBIDITY CURRENT FLOWS AT VARIOUS LOCATIONS IN THE TOTO 47 ENGINEERING PROPERTIES Shear Strength A test for shearing strength (cohesion) was performed at the top, middle, and bottom of all cores considered to be undisturbed and to have an unaltered water content. Where obvious disturbance of the core had taken place during collection, no shear strength tests were performed; however, in some instances, water content measurements were feasible although the exterior of the core was disturbed. Shear strength measurements were poner eer on the same core increments used in the sediment density determinations by carefully extruding the sample from with in the cylinder and into the testing device. The testing procedure is decribed in detail by Richards (1961) and is only briefly discussed herein. An unconfined compression testing device with plastic platens at either end of an axial rod was used to measure the compressive strength (2 times the shear strength) on sediments of moderate firmness. A stress-strain relationship is obtained by placing an ever increasing load on the upper end of the axial rod with the sediment increment standing upright beneath. Failure of the sample was taken by subsequently plotting the stress-strain data and taking failure at the point of greatest curvature in the plotted line, or arbitrarily, at 20 percent axial strain if the point of greatest curvature was undeterminable. When the sediment was soupy or not very cohesive, a vane=shear apparatus was used in which a vane was inserted into the sediment and rotated by a constant-speed motor. Degree of vane rotation and degree of applied torque was recorded at the be- ginning and during the test. Sample failure was determined at the major inflection point of the stress-rotation curve. The results of the shear strength tests are presented in Table VII and are thought to be sufficiently accurate for most engineering work. Richards (Ibid.) discussed the sources of disturbance to the sediment during the sampling, transporting, and labora- tory analysis. Because no information was available to estimate quantitatively the reduction of in-place strength, he concluded that values of shear strength obtained through the method outlined in his report are conservative by an unknown amount compared to in-place strength. Shear strength or cohesion values were determined in order to calculate the ultimate bearing capacity of the sediment. The ultimate bearing capacity (q,,) is defined as the average load per unit area required to produce failure by rupture of a supporting sediment mass, excluding any factor of safety, and is based on the formula: q, = 1-3 cNe + wd Ngt 0.4 Bw Ny, where cohesion, buoyant unit weight of the sediment, depth to center of sample increment tested, width of structure footing, and Ne, Ng, and Ny are bearing capacity factors. woazoao lol The formula is applicable to structures where the length to width ratio of the base is less than two (square or circular loads) and is usually reduced to q, = 1.3 ¢ Ne. Bearing capacity factors are a function of the angle of internal friction. Where the angle is zero (as is assumed for cohesive soils) Nc = 5.7, Ng = 1.0, and Ny = 0 as determined by Terzaghi and Peck (1948). Results from tests of core number 62-22 will illustrate the application of this formula. If a mass of 35 tons (buoyant weight) with dimensions 12' x 12' x 6' is placed on the bottom at the location of core 62-22 and without impact velocity, the resultant pressure or stress on the sediment would be 486 Ibs/ft2, and an ultimate bearing capacity of at least the same amount is required for support of the mass. Assurning a surface load of q, = 7.4 c, the cohesion necessary for support is 0.46 psi. In core 62-22 the core interval 0 to 7 centimeters has a tested cohesion of 0.53 psi, which (neglecting time) is sufficient for support of the mass. The majority of cores tested show a large increase in cohesion with depth in the sediment, and inversions, when present, are small in magnitude. Figure 12, which delineates areas in the TOTO of high and low cohesion values, is based on the aver= age cohesion throughout the individual core. From this figure the cul-de-sac sediments, except in two instances, have an average cohesion of less than 1.0 psi, which is the lowest in the channel. Near-flank sediments show a slightly higher cohesion, and axial sediments, except for a zone of less cohesive sediments southeast of Middle Bight, greatly exceed both areas. Although the differences in cohesion values throughout the channel are slight, it might be pointed out that an increase of one unit in the measured cohesion value presented in the example used in core 62-22 above would increase the ultimate bearing strength from 565 to 2,062 Ibs/ft2. It is noteworthy that cohesion values follow a trend corresponding to the 3 sedi- mentary environments delineated in the TOTO. The near-flank and cul-de-sac areas (low cohesion) represent environments of high water content, high organics, low den- sity, and high rates of sediment accumulation, whereas, the axial area (high cohesion) is characterized by relatively low water content, low organics, high density, and low rates of sediment accumulation. Figure 13 delineates values of surface organic carbon content and demonstrates the relationship between organic content and cohesion when compared with Figure 12. 49 FIGURE 12 AREAS OF HIGH (>1.0 PSI) AND LOW COHESION IN THE TOTO 50 e05e@ On 2% @07 FIGURE 13 DISTRIBUTION OF SURFACE SEDIMENT ORGANIC CARBON CONTENT (%) 5a Core No. 61-1 Ollie, 61-10 61-18 6252 62-10 62-15 62519 62-20 62-21 62-24 62-28 Shear strength and sensitivity of the TOTO sediments TABLE VII Depth in Core (cm) Near-flank Sediments a2 Shear Strength (psi) MMO ORY —HRO NOM ORR AON OOO ANN NOV FF] AEw (2) Sensitivity TABLE VII Shear strength and sensitivity of the TOTO sediments (Cont'd) Core Depth in No. (cm) 62-37 3 62-39 11 62-57 10 62-58 3 61-2 15 61-4 5) 61-6 Fe) Ollis7, Fs) 61-8 5 61-21 3 61-228 1] 62-2 27 Core Near-flank Sediments (Cont'd) Shear Strength (psi) QoQ 2530 ECHO © Axial Sediments 33 ho e NO — ° ° Ow —ONM FWW O— ONO DOD OUNW ANB OO OMMN —NO® NY Sensitivity 11 Core No. 62-3 6257, 62-8 62-16 62517, 62-18 2522 62-277, 62-29 62-30 62-31 62-34 TABLE VII Shear strength and sensitivity of the TOTO sediments (Cont'd) Depth in Core (cm) 20 65 120 44 88 147 54 —Oak NOt DOW OOW NWO —-4aH OWH NWO HOW NIOsO OCOh WOO NWO OS] OHO WOK BAS POSE PHS OS] OOOO OV] Ses WoO Shear Strength (psi) Axial Sediments (Cont'd) Sensitivity 10 14 Core No. 62-47 62-48B 62-49 62-50C 62-51B 62-52A 62-53 62-60 62-61 62-62 62-63 Ol=1 1 TABLE VII Shear strength and sensitivity of the TOTO sediments (Cont'd) Depth in Core (cm) 101 Shear Strength (psi) Axial Sediments (Cont'd) Saoo AWYoOo WOFo HCO =] oH oOo — AOMON ONNM WON TDM AO NOL — Northeast Providence Channel OOo S33 COeEoOo Iso OH NOW ONO NWH Cul-de-sac Sediments OZ 0.4 55 Sensitivity 11 TABLE VII Shear strength and sensitivity of the TOTO sediments (Cont'd) Core Depth in Core Shear Strength No. (cm) (psi) Sensitivity Cul-de-sac Sediments (Cont'd) O\=)Z 5 OFS 25 0.4 61-16 5) ORS 28 162 51 0.7 62-40 26 0.8 129 0.5 2 62-4] 3 0.1 75 ORS 2 62-42 3 0.1 79 0.3 2 137 eo 62-43 11 0.6 50 0.8 3 62-44 8 0.8 67 Oo 6 13] 0.9 62-45 31 1.4 63 0.7 4 9A 0.6 62-46 26 Di. Sy 0.8 5 62-54 19 0.4 a, 0 5 62-55 3 0.2 58 0.8 62-56 3 0.2 47 0.8 2 66 lod 62-59 22 1.0 56 Sensitivity Sensitivities of core samples are given in Table VII. The values range from 2 to 16 (slightly insensitive to slightly quick) and show a predominance of very sensitive sediments. The cul-de-sac sediments are the least sensitive, axial sediments the greatest, and near-flank sediments intermediate between the two but tending more toward sensitivities similar to the cul-de-sac. 57 BOTTOM PHOTOGRAPHY Camera stations were located throughout the channel at predetermined positions. Although the photographs from this study cannot be considered to be representative of the entire channel bottom, the close-spaced coverage obtained along the fairly ex- tensive tracks provides excellent representation in the area photographed, and, from these photographs and the work of Armstrong (1953) and Athern (1962 b) a general idea of the microrelief can be obtained. Camera lowerings at Stations 1, 2, and 3 were occupied while the ship was at anchor, and the lowering at Station 4 was made while drifting. The ship's position was plotted and annotated during the camera lowerings on a Decca Hi-Fix plotter, and a graphic record of the ship's position, hence, the camera location (+ 10 feet), was obtained during the two-hour period while the camera was in operation off the bottom (Fig 14). Camera lowering Station 4 is represented on Figure 14 by a line trending north- northwest across the center of the TOTO off High Cay. The paths followed by the other camera stations (1, 2, and 3) are also presented in this figure, and variations in ship location while at anchor are graphically demonstrated. In the graph of station 2, the ship completed one cycle of it's swing on the anchor cable, and the camera was brought up while halfway along the return swing. The graph of Station 1 demonstrates the extreme to which the ship varied in posi- tion while anchored. In this instance, the vessel was subject to a fairly long-period pitch superimposed on the arc traversed around the anchoring point. The combination of swinging and surging produced a figure 8 pattern which the camera system followed. The procedure of plotting the ship movement, annotating the plot, and including a synchronized clock in the data chamber of the camera permits calculations to enable one to delete duplications of track coverage where present. Two out of four of the camera stations produced pairs of stereo photographs (Stations 1 and 4), while at the remaining stations malfunctioning of one of the two cameras re- sulted in only one roll of exposures during the course of the lowering. The photographs generally cover an area approximately 13.5' x 8' or 108 ft2, and overlapping of pairs exceeds one half the area photographed. Camera Station Data Station ] Depth: 1,250 meters Number of Exposures: 362 Length of Camera Track: 457 meters Track Position: 23° 27.4'N, 76° 58.8'W (Coordinates for center of track) Camera Performance: Stereographic pairs obtained from all exposures. 58 START 0855 2100 STOP 0940 1050 STOP k——— 439 M ——>| LOWERING | LOWERING 2 LOWERING 4 77°3510' 05° 77°3500' 55 50 45° 77°3440" LOWERING 3 FIGURE 14 PLOT OF SHIP'S POSITION DURING CAMERA LOWERINGS 39 Station 2 Depth: 1,390 meters Number of Exposures: 438 Length of Camera Track: 462 meters Track Position: 24° 00'N, 77° 15.9'W (Coordinates for center of track) Camera Performance: Right camera malfunctioned. Station 3 Depth: 1,500 meters Number of Exposures: 276 Length of Camera Track: 512 meters Track Position: 24° 27.5'N, 77° 31.5'W (Coordinates for center of track) Camera Performance: Left camera malfunctioned. Right camera produced 90 percent double exposures. Doubly exposed frames were, nevertheless, adequate for interpretation, and the good exposures obtained appear representative of the camera track. Station 4 Depth: 1,929 meters Number of Exposures: 572 Length of Camera Track: 1,572 meters Track Position: 24° 41.6'N, 77° 34.8'W (Coordinates at start of track) Camera Performance: Stereographic pairs obtained from all exposures. Biology Animal life and evidence of its existence is extremely sparce along the tracks traversed by the camera system, and at only one site (Station 2) was there appreciable evidence, both direct and indirect, of a significant benthic population. The majority of photographs obtained from all lowerings are devoid of animal life. A few holothurians were present to some degree in all the camera tracks (Plates III and V1), and occasional brittle stars (Plate II1) were observable. Filamentous plant debris (probably derived from the shallow surrounding banks) was present on all tracks (see Plate IV for an example). Stations 1 and 2 (Plates II] and V) show the greatest direct and indirect evidence of organic activity, while, on the other hand, Stations 3 and 4 (Plates VI and VII) show no more than a featureless, unconsolidated calcareous ooze throughout the majority of the track. 60 Relative to the other camera tracks, Station 2 shows the most evidence of organic activity. Throughout the entire length of the track the bottom is thoroughly pitted and marked by trails, tracks, mounds, and burrows. A number of the mounds present in this and the remaining plates are thought to represent pebble and cobble debris which has been covered by sediment. These mounds are differentiated from organi- cally derived iiounds by the lack of an axial hole. Some sessile forms are present in the exposures from Station 2 which are suggestive of hydroids. Armstrong (1953) reported that a very slow rate of sediment deposition prevails in the center of the TOTO, and any features on the bottom would tend to be preserved for a long tire. If this is true then a small benthic population could produce bottom features which could be mistaken for a substantial benthic community. In any event, the information from the photographs point to an extreme paucity of bottom dwelling organisms on the floor of the TOTO. The low organic carbon values (consequently insufficient nutrients) obtained from analysis of the sediments substantiates these findings. Bottom Features Relief not connected with animal activity or particle-by-particie deposition over pre-existing features is present to a limited degree in specific areas along two of the camera tracks. Photographs from Stations 2 and 3 showed no unexpected evidence of past or present constructional processes for the depth and position of the lowering, and, on the basis of the photographs, it is inferred that limited benthic faunal activity com- bined with a slow rate of sediment accumulation constitutes the dominant microrelief building processes. Station 1, in the cul-de-sac, shows an outcrop of either a well lithified calcareous material covered by a sedimentary veneer or a semilithified bottom material (Plate IV). The outcrop strikes northeast, is of undeterminable thickness, and occurs on only two exposures (the closest points to the flank of the cul-de-sac) along the entire track. A slab of the outcropping material is observable in the top left photograph of Plate IV, and it appears to have moved, or is now moving, in a southerly direction. In the bottom two photographs on the same plate, circular pits or depressions a few centimeters in di- ameter and depth are apparent. The depressions show very steep sides and are located only in the photographs taken adjacent to the walls of the cul-de-sac. The dark material enclosed by a depression may represent pebble detritus washed off the adjacent banks; however, the apparent filamentous appearance of the material somewhat negates this possibility. 61 Camera lowering Station 4, although presenting the most featureless bottom for the first 1,500 meters of track, showed the most unexpected features of all the photo- graphs. At 24° 41'49"N, 77° 35'01"W the camera system traversed a well indurated limestone outcrop approximately 24 feet across and terminating in a 3-foot vertical to concave scarp striking northeast (Plate VIII). Stereographic examination of the outcrop reveals cavities and depressions in the exposure which range from 5 to 60 centimeters in both width and depth, and, in many instances, unconsolidated sediment covers the base of the depression. A number of the cavities are interconnected to form a network of channels, and almost all display sharp angular rims (Plate 1X). A micro- topographic contour map of the edge of the outcrop is presented in Plate X. Busby (1962) discussed this outcrop and the possible origin of the features, and concluded that the depressions are solution basins of subaerial or littoral zone origin that were formed when the outcrop or the floor of the channel was at an elevation of about 1,900 meters higher than at the present. Bottom Currents Twenty-four meters northwest of the outcrop observed in the photographs from Station 4, pebble and cobble-sized debris is present, and immediately adjacent to this material are well developed oscillatory ripple marks facing northeast (Plate XI). The ripple marks at this location appear symmetrical and average 13 centimeters from crest to crest. Utilizing various sources of data, a rough estimate of the minimum current veloc- ity necessary to produce these ripples can be calculated. The average median diam~ eter of the surface sediments in the area of ripple mark formation is 15 microns, and, according to Hjulstrom (in Trask, 1955), a mean water velocity of 28 to 43 centimeters per second is required to instigate movement of particles of this diameter. Ripple marks disappear or are obliterated when water velocity exceeds a critical value, which in the instance of very coarse sands is 90 centimeters per second (Shipek, 1961). Con- sequently, a current of minimum velocity of 28 to 43 centimeters per second and maxi- mum velocity of 90 centimeters per second is necessary for formation and maintenance of the ripple marks observed in Plate Xl. The maximum velocity is probably much higher than that necessary to obliterate the ripples observed in this area; however, as no data are available concerning ripple marks in dominantly silt-sized sediments, this value is taken as the maximum in lieu of further information. Menard (1952) attributed symmetrical ripple-mark development at 4,500 feet in the Pacific Ocean to short-period water oscillations perhaps caused by tides, tsuanamis, or internal waves. Inman (1957) pointed out that symmetrical ripple marks require oscillatory currents for formation, since an unidirectional current produces asymmetrical ripples with one slope at the angle of repose of the sediment and the other more or less 62 concave. It is expected that at the depth (1,929 meters) of ripple occurrence in the TOTO, either internal waves or tidal oscillations produced the ripple marks observ- able, although the latter is more likely. As mentioned above, adjacent to and south of the ripple-marked area is pebble- and cobble-sized debris which probably has been derived from the reef areas bounding the channel. From the photograph in Plate XI the ripple marks are apparent, and close study of the photograph shows the finer material to be encroaching upon the larger debris. The distribution of pebble and gravel material around the large cobble-sized fragment in the upper right-hand half of this photograph suggests a strong southerly current which is producing a lag deposit in this area with a net movement of sediment toward the south. 63 SUMMARY The significant results and conclusions from the bottom sediment investigations in the TOTO by this Office and previous investigations by others are summarized below: 1. The TOTO is a long, narrow channel in the Great Bahama Bank which gradu- ally increases in depth from about 700 fathoms in the southern cul-de-sac area to 1,300 fathoms in the northern portion at the commencement of Northeast Providence Channel. 2. The flanks of the TOTO are steep (15 to 20°) bare rock walls to depths of 100 to 200 fathoms. Below this depth to the bottom of the channel the slope is more gentle, incised by gullies normal to the Bank edge and sediment covered. 3. The sediments on the floor of the channel are: a. Almost wholely composed of calcium carbonate, b. Dominantly silt-sized particles with a slight increase in sand in sediments collected from central reaches of the channels, c¢. Composed predominantly of the tests of planktonic foraminifera, pteropods, and reef detritus, and d. In general, poorly sorted. 4. Areducing environment prevails in the sediments on the flanks and, toa lesser degree in the cul-de-sac, while an oxidizing environment prevails in the sediments in the flat central reaches of the northern, elongated portion of the channel. 5. Sediment density is greatest in the axial region and lowest in the near-flank and cul-de-sac areas; conversely, water content, void ratio, and porosity are lowest in the axial region and highest in the near-flank and cul-de-sac areas. 6. Sediment density generally increases with depth in the sediment while water content, void ratio, and porosity decrease. 7. Over one-half of the sediment column sampled in the axial and cul-de-sac areas is the result of turbidity current deposition, while the near-flank sediments appear to be primarily the result of particle-by-particle accumulation from the over= lying water column. 64 8. Turbidity currents originate on the upper flanks of the channel, flow down slope at high velocity within the gullies, and distribute the sediment load locally on the channel floor. 9. Frequency of the turbidity flows is greatest in the cul-de-sac area and becomes less frequent northward in the channel. Rate of sediment accumulation is highest on the channel flanks and becomes less northward from the cul-de-sac along the channel axis. 10. Ultimate bearing strength of the sediment is lowest in the cul-de-sac and near-flank areas, highest in the axial area, and can be shown to follow the same trend as the organic carbon and water content of the sediments. 11. Bottom photographs show a paucity of benthic fauna, and, in general, a relatively featureless, unconsolidated ooze covers the channel floor. 12. The photographs reveal a bare rock outcrop at 1,000 fathoms in the center of the channel off Fresh Creek. Features in the outcrop indicate subaerial erosion of the exposure at some earlier geologic time. 13. Ripple marks present in some of the bottom photograph suggest a bottom current at 1,000 fathoms of at least 0.3 to 0.7 knot. 65 REFERENCES CITED Agassiz 1894 A reconnaissance of the Bahamas and of the elevated reefs of Cuba in the steam yacht "Wild Duck" January to April 1893. Bull. Mus. Comp. Zooley avenZo non, sppemlOZO3r Allison, L. E. 1935 Organic soil carbon by reduction of chromic acid. Soil Sci., v. 40, pp. 311/=320. Armstrong, J. C. 1953 Oceanography of the Tongue of the Ocean, Bahamas, B. W. 1. Office of Naval Research, Nonr-04501, 12 p. Athern, W. D. 1962a Bathymetric and sediment survey of the Tongue of the Ocean, Bahamas, Part |: Bathymetry and sediments. Woods Hole Oceanog. Inst. Ref. No. 62-25, 17 pp. - - = 1962b Bathymetric and sediment survey of the Tongue of the Ocean, Bahamas, Part Il. Bottom photographs. Woods Hole Oceanog. Inst. Ref. No. 62-27, 3 Don ZO fallo Busby, R. F. 1962 Subaerial features on the floor of the Tongue of the Ocean, Bahamas. NAVOCEANO IMR No. 0-48-62. Unpublished Manuscript. Drew, G. H. 1914 On the precipitation of calcium carbonate in the sea by marine bacteria, and on the action of denitrifying bacteria in tropical and temperate seas. Carnegie Inst. Washington, Pub. 182, v. 5, pp. 7-45. Eardley, A. J. 1951 Structural geology of North America. Harper & Bros., New York, p. 573. Ericson, D. B., M. Ewing, and B. Heezen 1952 Turbidity currents and sediments in North Atlantic. Bull. Amer. Assoc. Petrol. Geol., v. 36, pp. 489-511. ---, M. Ewing, G. Woolin, and B. Heezen 1961 Atlantic deep-sea sediment cores. Bull. Amer. Assoc. Petrol. Geol. v. 72, pp. 193-286. Field, R. M., and collaborators 1931 Geology of the Bahamas. Bull. Amer. Assoc. Petrol. Geol., v. 42. pp. 759-784. Goldmen, M. 1. 1926 Proportions of detrital organic calcareous constituents and their chemical alteration in a reef sand from the Bahamas. Carnegie Inst. Washington Pub. 344, v. 23, pp. 39-65. 66 Hess, H. H. 1933 Interpretations of geological and geophysical observations in Navy Princeton Gravity Expedition to the West Indies in 1932. U. S. Navy Hydrographic Office, Washington, D. C., pp. 27-53. Hjulstrom, F. 1955 Transportation of detritus by moving water. In recent Marine Sediments, a Symposium, Soc. Econ. Paleon. and Min., Special Pub. No. 4, Parker D. Trask, Editor, pp. 5-31. ling, L. V. 1954 Bahaman calcareous sands. Bull. Amer. Assoc. Petrol. Geol. Yo 837 [90 WV Inman, D. L. 1957 Wave generated ripples in near shore sands, Dept. of the Army Technical Mem. No. 100, 41 pp. Kuenen, Ph. H. 1953 Significant features of graded bedding. Bull. Amer. Assoc. Petrol. Geol., v. 37, pp. 1044-1066. - - -, andH. W. Menard 1952 Turbidity currents, graded and nongraded deposits. Jour. Sed. Pet., v. 22, 83-96. Marine Laboratory, University of Miami 1958 Oceanographic survey of the Tongue of the Ocean. Technical Report, 26 September 1958, v. 1. Menard, H. W. 1952 Deep ripple marks in the sea. Jour. Sed. Pet., v. 22, | )90 Sher Nelson, R. J. 1853 On the geology of the Bahamas, and on coral-format ions generally. Geol. Soc. London, Quart-Jour. v. 9, 200-215. Newell, N. D. 1955 Bahamian platforms. in: The Cruise of the Earth, A sym- posium, Geol. Soc. Amer., Special Paper 62, pp. 303-315. ---, J. K. Rigby, A. J. Whiteman, and J. S. Bradley 1951 Shoal Water geology and environments, eastern Andros Island, Bahamas, Bull. Amer. Mus. Nat. mliBlog Wo V7 Os NS. - - -, and J. K. Rigby 1957 Geologic studies on the Great Bahama Bank; in: Regional Aspects of Carbonate Deposition, a Symposium with discussions, Soc. Econ. Paleon. Min., Special Pub. No. 5, pp. 15-79. Olausson, E. 1961 Studies of deep-sea cores. Reports of the Swedish Deep-Sea Expedition 1947-1948, v. 8, fasc. 4, pp. 335-391. 67 Ostlund, H. G., A. L. Bowman, and G. A. Rusnak 1962 Miami natural radio- carbon measurements. Radiocarbon, v. 4, pp. 51-56. Richards, A. F. 1961 Investigations of deep-sea sediment cores. |. Shear strength, bearing capacity, and consolidation. U. S. Navy Hydrographic Office, Washington, D. C., Technical Report 63, 70 pp. Revelle, R. R. 1944 Marine bottom samples collected in the Pacific Ocean by the Carnegie on its seventh cruise. Carnegie Inst. of Washington Pub. 556, pp. 1-183. Rusnak, G. A., and W. D. Nesteroff 1962 Modern turbidites: terrigenous abyssal plain versus bioclastic basin. Contrib. No. 000, the Marine Lab. Univ. of Miami, (In Press) . Schuchert, C. 1934 Historical geology of North America, v. 1. Antillean- Caribbean region. John Wiley & Sons, New York, 811 pp. Shipek, C. J. 1961 Microrelief on the sea floor. Sci. Teacher, v. 28, 7 pp. Siegler, V. B. 1961 Bathymetric reconnaissance of Exuma Sound. The Marine Laboratory, Univ. of Miami Technical Report 61-4, 9 pp. Talwani, M., J. L. Worzel, and M. Ewing 1959 Gravity anomalies and structure of the Bahamas. Lamont Geol. Obs., Columbia Univ., New York, Unpubl. Bop [eo U=7o Terzaghi, K., andR. B. Peck 1948 Soil mechanics in engineering practice. John Wiley & Sons, Inc., New York, 566 pp. Thorp, E. M. 1936 Calcareous shallow-water marine deposits of Florida and the Bahamas. Carnegie Inst. Washington Pub. 452, pp. 37-143. Turkian, K. K. 1956 Rapid technique for determination of carbonate content of deep-sea cores. Bull. Amer. Assoc. Petrol. Geol, v. 40, pp. 2507-2509. Vasicek, M. 1953 Graded bedding and some sedimentary mineral deposits: Sbornik Ustredniho Ustavu Geologickeho, Svazek XX, Nakladatelstvi Ceskoslovenske Akademie, Praha, 52 pp. Vaughan, T. W. 1913 Remarks on the geology of the Bahamas Islands, and on the formation of the Floridian and Bahamian oolites. Jour. Washington Acad. Sci., v. 3, n. 10, pp. 302-304. 68 Vaughan, T. W. 1914 Preliminary remarks on the geology of the Bahamas, with special reference to the origin of the Bahaman and Floridian oolites. Carnegie Inst. Washington Pub. 182, v. 5, pp. 47-54. - - - 1918 Some shoal-water bottom samples from Murray Island, Australia, and comparisons of them with samples from Florida and the Bahamas. Carnegie Inst. Washington Pub. 213, v. 9, pp. 239-288. Wentworth, C. K. 1922 A scale of grade and class terms for clastic sediments. Jour. Geol., v. 30, pp. 377-392. Woodring, W. P. 1928 Tectonic features of the Caribbean region. Third Pan- Pacific Sci. Congr. Tokyo, 1926, Proc., pp. 401-432. Worzel, J. L., M. Ewing, and C. L. Drake 1953 Gravity observations at sea, Pt. |, the Bahama Islands region. Bull. Geol. Sco. Amer., v. 64, pp. 1494- 1495 (abstract). 69 “SadLAWILNAD NI FIVOS °~4AYOD ANV14-YVIN JH! JO YOTOD GNv JYNLXaL N3AJ “HLOOWS JHL O1 GISOddO SV 3YOD IVIXV JHL JO FYNLXAL HONOY GNv ‘SGNV4@ YO1OD “4NH YSLHOIM JLON *(WOLLO®) S1-Z9 JYOD ANV1S-YVIN GNv (dOL) 91-29 IYOD TWIXV | ALVid Tak “Sada LIWILNAD NI FIVDS *SIFSAYD SNNAO FHL AO SACOdOUALd JYV SYFLAWILNAD €6 LV SATDILYVd SNIT-JIGFIN * (14397 OL LHOIY) NI GavMdN ANId Ol ISYVOD WOU JAZIS FIDILYVd NI NOILVGVYS JLON *d87-29 FYOD NI JINOZ JLIGIGUNL JYOD FHL Il] alW1d VO PLATE II] REPRESENTATIVE BOTTOM PHOTOGRAPHS FROM CAMERA STATION 1. NOTE HOLOTHURIANS AND THEIR TRACKS IN LOWER LEFT PHOTOGRAPH, AND BRITTLE STAR JUST ABOVE CENTER IN TOP LEFT PHOTOGRAPH. THE RADIAL ARRANGEMENTS PRESENT THROUGHOUT ALL THE PHOTOGRAPHS ARE BELIEVED TO REPRESENT A SEARCH PATTERN BY SOME TYPE ANNELID. 73 PLATE 1V BOTTOM PHOTOGRAPHS FROM CAMERA STATION 1. NOTE OUTCROP IN ; TOP RIGHT PHOTOGRAPH AND BOULDER IN TOP LEFT. LOWER TWO PHOTOGRAPHS SHOW CIRCULAR PITS OR DEPRESSIONS AND SCATTERED PLANT DETRITUS. 74 | PLATE V REPRESENTATIVE BOTTOM PHOTOGRAPHS FROM CAMERA STATION 2. 75 PLATE VI REPRESENTATIVE BOTTOM PHOTOGRAPHS FROM CAMERA STATION 3. 76 PLATE Vil REPRESENTATIVE BOTTOM PHOTOGRAPHS FROM CAMERA STATION 4. NOTE CRUSTACEAN IN BOTTOM RIGHT PHOTOGRAPH. 77 PLATE VIII SCALE (FEET) 5) 4 5 6 7 MOSAIC OF THE OUTCROP AS PHOTOGRAPHED BY THE CAMERA SYSTEM 78 em AY SCALE 1:34 PLATE 1X CAVITIES AND DEPRESSIONS AT 1,000 FATHOMS IN THE TONGUE OF THE OCEAN. THE SCARP PRESENT IN THE UPPER PHOTOGRAPH IS APPROXIMATELY 3 FEET DEEP. 79 PLATE X MICROTOPOGRAPHIC CONTOUR MAP OF PLATE |X CONTOUR INTERVAL: 1 DECIMETER, SCALE: 1:17.8 80 PLATE X1 BOTTOM PHOTOGRAPHS FROM CAMERA STATION 4. OBSERVE THE STREAMING OF FINER FRAGMENTS SOUTHWARD OF THE LARGE COBBLE ON THE LOWER PORTION OF THE TOP PHOTO- GRAPH; ALSO, THE SMOOTHER, MORE PLANATED APPEARANCE OF THE RIPPLE MARKS TO THE RIGHT OF THIS PHOTOGRAPH AS OPPOSED TO THE RIPPLES ON THE BOTTOM PHOTOGRAPH. SCALE APPROXIMATELY 1:34. 81 ee Siiy SURED ft RS SFT O¢LA IAI Petey Tak ) Tie ee). aM Be My : ‘ta 475° say SR A Pe ae Ba Tse er) OT nee ee ' an a oi iil Be bane + da TAA a Core No. 62-1] 62-2 62-3 62-4 62-5 62-6 62-7 62-8 O2=9 62-10 62-11 62-13 62-14 62-15 62-16 62-17 62-18 62-19 62-20 62-21 62-22 62-23 62-24 62-25 62-26 62-27 62-28 62-29 62-30 62-31 62-32 62-33 62-34 62-35 62-36 62-37 62-38 62-39 APPENDIX | Latitude (N) 24° 58.2! 24° 57! 24° 55.2! 24° 51.9! 24° 43! 24° 40' 24° 40.1! 24° 44,1! 24° 49.2! 24° 45! 24° 41.2! 24° 35! 24° 35! 24° 24' 24° 24.2! 24° 28! 24° 24.6! 24° 27" 24° 22! 24° 16.1! 24° 17.1! 24° 17.9! 24° 19! 24° 14.2! 24° 03! 24° 04.6! 24° 01.1! 23° 58.9! 23° 55.2! 23° 57.7! 23° 57.9! 23° 53.2! 23° 44.7! 23° 39! 23° 34! 23° 28.9! 23° 27! 23° 28! Longitude (W) 71 39i53" 77° 40! 77° 45.8' 77° 50’ 77° 43! 77° Al! 71-2 SON V7? SS1\" VU? SVS! Uy? 7Ass UYU? P\o\\" 77° 30" UT? So TY? SIP 77° 34.7' 77230 77° 22.4! Hl \Oo7 UY? \\S» 77° 14.9" UW? lace Vf? 743.q\\" TM STia2s 77° 34.4! Uy? Lp Ul C508 TI NGA VY? \Vo 1" Ud? Sol" The Plo UI? ef" UU PeS\oo% TU Vp: JY? \\e UY? \ex VY? ead" 76° 59.3' The SII" 83 CORE STATION DATA Depth (m) 677 1829 1840 558 580 498 1710 1889 841 950 988 1683 640 457 1480 1868 1202 1051 525 1041 1463 148] 768 430 612 1399 1728 1353 1344 1362 805 823 1134 1234 1243 1066 WA? 1253 Length of Core (cm) 100 151 127 Grab Sample 13 Grab Sample 158 81 31 147 Grab Sample 153 27 129 175 12] 121 127, 140 148 88 40 59 13 Grab Sample 116 152 136 126 59) 12 Grab Sample 157 Grab Sample APPENDIX | Latitude (N) 232733) US? God) 23° 46' 23° 47' A” BBals} Je?) BE) ||" 23° 56' 24° 4l' 24° 4].3' 24° 41.3! 24° 28.5! 24° 30' 24° 31.6! 23° 50.8! 23° 45.1' 23° 47' 23° 39.4! 23° 34! 7° CA) ol! 2S) GoD! DammADs 73> GX 74}? \\@ots) 25° 41' 24° 46.6' 24° 49.7' 24° 30' 24° 29.6! 24° 10.3' 24° 10.5! 24° 09.3! 23° 49.7' 23 NAT 732 3) ois) 1B SoS} 23° 39.7' 24° 40,5! 24° 39! CORE STATION DATA (Cont'd) Longitude (W) Ie? OI U7? WS 77° OS! 762 53)20) Tks S858). 77° 00' Ud? Woe HL? Sis) Uf? Se) 77° 42' Ul? hy 7T° 34.9" Ul? 76° 45.8' 76° 46.2" 76° 38.3" er BP oS 76° 39' Te? BH 76° 47' 77° 47' WU? SoD Wl S018) 77° 34! 77° 44.6' VI? M8: Vo? Zo? Uy? Sey: UT? Ls Ul? Zot WO Noi" UI? os Ul? WS Td? (o7 ky? S500 77° 14.3' 7773059: VU? SS 84 Depth (m) 1326 1330 1330 1134 1244 1253 1198 1810 1300 811 1609 1573 1640 1250 1293 1262 1234 1174 871 1282 1701 1300 2800 1728 1225 1875 1280 1590 1161 1481 934 1170 1414 1390 1314 1202 1500 1774 Length of Core (cm) 138 149 [=z 801-aL Aqsng *4 ||@msoy sdoysno spwDYyog /UDeIO eYs jo enBuoy 944.40 ABojoed eujsowgns 291414 AydasBoure29 = UDE2O a4) yo enBuoy Lil @) 24s jo enBuoy — AydosBouns20 4Boj095 SUPIDWGNS — UDBIO 244 40. enBuoy UD820 ays jo enBuo} - ABojoes euysnuqns 80I-aL Aqsng *4 {jo*soy 2404IND soWDYdY /UDS2O ey) yo enBuoy 244 yo ABojoes) euysowgqns :9)41) AydosBouns2Q ~ uDe2Q 244 jo anBuoy up8209 ays yo enBuoy - AydoiBoune20 ABoj095 @UjJDWGNS - UD®20 E44 jo enBuoy UD220 ey) jo enBuo) ~ ABojoas euysowgns *UO1;OULIOJUY Jo $@9.1N0s peys};qndun pup paystiqnd yjoq Uo pesDg $1 |DJJoDyy “sDWWDYDY ‘UD2DQ OYy jo enBuo} ey) jo ABojoeB eujsnwqns ays uo yiodes BAsusYesdwod D syUesesd UO} sD21;Gnd si4yy 69 04.99 °d soouciajoy *(B01-yl) “ddo | ‘seyojd LL “°s8y v1 “°F 7B °7961 sequerony ‘Aqsng “4 119%s0y Aq ‘SwwyHWd ‘NV3D0 3H1 JO INDNOL JHL JO ADNO10IO ANINWWANS 921430 2!YdosBoun|20 jpADW) “Ss °f) “Uo |{OUUOJUY Jo $821n0s peystiqndun pup paysiiqnd yyoq Uo pasDg S| |DlJeyDyy *sDWIDYDg ‘uD220 ays jo enBuoy 944 jo ABojoe6 ouysowgns ayy Uo ysodas @A}sueyeidwos D syueseid UOJ 4D>D1;GNd siyy 69 94.99 °d seouaiajoy *(801-¥1) “ddo | ‘soyjd LL “*s8y yt “*d 9g °7961 sequiaaony ‘Aqsng “4 1yemsoy Aq ‘SywwHv@ “NVIDO 3HL JO INONOL IHL JO ANO1OIAD ANIWWaANS 22133 2!ydosBouDe90 DAD) *S *) 801-a1 Aqsng *4 |J@asoy :40ysno SpWOYDG /UD9IO eY44 yo enBuoy 24s yo AGojoas euysowqns 21415 AydosBouns29 - u022Q ey) jo enBuoy ub290 ays yo enBuo| — AydosBouna2G é ABoj0285 QujIDWgNs — UDs2Q ey) yo enBucy uD220 ey4 jo enBuoy - ABojoas eujsowgns 80I-uL Aqsng *4 |J@Msoy :soysno spwpyog /UDIIO ey4 yo enBuoy ays yo ABojoas eurspwgns :9441) AydosBoune29 - uD92Q ayj jo anBuoy up220 ays yo anBuoy ~ Aydoi5o0un92GQ, ABoj0a5 auliowqns =- uD39Q ous 4° anBuoy uD920 au; jo enBuoy ~ ABojoed aulsipwgqns * UO} ;OULOS UY Jo s824n0$ paystiqndun pup paysijqnd yyoq Uo pesng s} |OUajDyy “sDWUDYDG ‘UDE2C0 a4 JO anBuoy ays jo ABojooB auysowgns ays uo ysodas SAlsueyeidwio> D syuasosd UosyDO!;Gnd siy) 69 94.99 °d saouaiajay 2 *(801-¥) “ddo | ‘syd LL “*s8y 71 “*d yg °Z961 sequienon “Aqsng "4 112"s0y Aq ‘SwWwHVG “NV3D0 3H! 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