557
IL6gui
1987-C
PARK RIDGE-NORTH SHORE AREA
Cook and Lake Counties
Geological Science Field Trip
David L. Reinertsen
Field Trip, 1987C October 3, 1987
Department of Energy and Natural Resources
ILLINOIS STATE GEOLOGICAL SURVEY
Champaign, IL 61820
A GUIDE TO THE GEOLOGY OF THE PARK RIDGE - NORTH SHORE AREA
By
David L. Reinertsen
3 October 1987
GEOLOGICAL SCIENCE FIELD TRIPS are free tours conducted by the Educational
Extension Unit of the Illinois State Geological Survey to acquaint the public
with the geology and mineral resources of Illinois. Each is an all-day
excursion through one or several counties in Illinois; frequent stops are made
for explorations, explanations, and collection of rocks and fossils. People
of all ages and interests are welcome. The trips are especially helpful to
teachers in preparing earth science units. Grade school students are welcome
but each must be accompanied by a parent or guardian. High school science
classes should be supervised by at least one adult for each ten students. A
list of available earlier field trip guide leaflets for planning class tours
and private outings may be obtained by contacting the Illinois State
Geological Survey, Natural Resources Building, 615 East Peabody Drive,
Champaign, IL 61820. (217) 244-2407 or 333-7372.
Digitized by the Internet Archive
in 2012 with funding from
University of Illinois Urbana-Champaign
http://archive.org/details/guidetogeologyof1987rein
A GUIDE TO THE GEOLOGY OF THE PARK RIDGE - NORTH SHORE AREA
David L. Reinertsen
AN OVERVIEW
General Setting and History
The Park Ridge-North Shore Area Geological Science Field Trip will acquaint
you with some aspects of the general geology, topography, and mineral resour-
ces of a portion of the Chicago Metropolitan Area, home to 7- to 8-million
people. The information in this guide leaflet, coupled with your own personal
observations, will show you how geology relates to regional land-use planning
and urban environmental improvement, to construction problems (structure
foundations, highways, etc.), and to locating, developing, and conserving our
mineral and water resources. The geographic location and geologic setting of
the Chicago Metropolitan Area strongly influenced its growth and development
from the early 1800s. Cheap water transportation, via the Great Lakes and the
Illinois Waterway and the availability of mineral and water resources, led to
the area's early rise to importance. A short time later, a number of rail-
roads converged on the city to strengthen further its national and inter-
national importance and influence.
Chicago's rapidly expanding populace has not adjusted easily to its environ-
ment. Although many land-use problems have been resolved, others, such as
urban sprawl and waste disposal and their interrelationships with the mineral
resources of the area, have not been understood. We trust that as awareness
and knowledge about the problems and some of their possible solutions become
better known, more problems will be resolved so that the area will retain its
desirability as a place in which to work and live.
This field trip area is located in the northern part of Cook and the south-
eastern part of Lake Counties, where most of the present villages and cities
were once known as "bedroom communities;" that is, they were ideal residential
communities within easy commuting distance of downtown Chicago. The popula-
tion of the 16 communities embraced by this field trip now totals nearly
500,000 people and the complexion of some of these communities is changing as
more offices and industries move to the suburbs, where their workers now live.
Realizing that the economic and natural assets of the metropolitan area would
be severely stressed by uncontrolled growth, the General Assembly passed
measures that led to the establishment of the Northeastern Illinois Planning
Commission to encompass the six counties in this part of the state lying east
of the Fox River. The Commission is collecting and integrating data on the
physical and environmental characteristics of the counties as a basis for
long-range planning. The Geological Survey generated and developed a con-
siderable amount of data, much of it compiled on maps, for the Commission.
Such information on the soils, rock materials, groundwater, and surface water
contributes to an awareness of the natural assets of the counties and to an
understanding of environmental limitations and problems. Development based on
such an awareness presumably enhances and protects the physical environment
rather than causes its deterioration.
Physiography and Geology
The Park Ridge-North Shore area in northeastern Illinois is situated in the
Wheaton Morainal Country and Chicago Lake Plain of the Great Lake Section,
Central Lowland Province (fig. 1). The Great Lake Section is separated from
the Till Plains Section to the south and west because of the very pronounced,
roughly concentric morainal ridges surrounding the Lake Michigan basin, more
abundant lakes, and the extent of lacustrine (lake) plains here.
The Chicago Lake Plain forms a relatively flat surface, for the most part
underlain by glacial till, that slopes gently lakeward. The numerous glacial
moraines of the Wheaton Morainal Country form a more complex topography that
contains more lakes and swamps than do the open stretches of the adjacent Till
Plains Section.
Geologically, the Park Ridge-North Shore area has undergone many changes
throughout millions of years of geologic time. Igneous and possibly meta-
morphic rocks compose the ancient Precambrian basement that lies deeply buried
beneath some 3,100 to 3,600 feet of younger sedimentary rock strata that were
deposited in shallow seas that repeatedly covered this part of our continent.
Most of these sedimentary bedrock strata are Paleozoic formations ranging in
age from Cambrian through Silurian (from about 570 to nearly 408 million years
old) (fig. 2). Younger Paleozoic bedrock strata, which are known from out-
crops just a few miles away from the field trip area, covered this area at one
time. Then, during the millions of years following the close of the Paleozoic
Era and before the Pleistocene glaciers advanced into Illinois, 1 to 2 million
years ago, an unknown thickness of these strata was eroded away. Paleozoic
bedrock strata in the Chicago area are not flat lying or "layer cake" in their
attitude. Instead they are gently warped up across the Kankakee Arch, a
broad, northwest- to southeast-trending structural arch that connects the
Wisconsin and Cincinnati Arches (fig. 3). The Kankakee Arch separates two
broad structural basins--the Illinois Basin (fig. 4) to the southwest and the
Michigan Basin to the northeast. The field trip area lies along and slightly
east of the crest of the Kankakee Arch. The bedrock strata here are tilted
slightly toward the northeast about 10 to 15 feet per mile, less than 1° dip
and not perceivable by the eye. Locally there are exceptions to these gentle
dips. Tilting of the bedrock strata took place several times during the
geologic past with the result that the bedrock strata are not parallel to each
other.
An unusual geologic feature of this area is the Des Plaines Disturbance, an
intensely faulted structure about 5.5 miles in diameter that has displacements
of as much as 600 feet (fig. 5). None of this structure, however, is visible
at the ground surface; the description and interpretation are based on the
records of more than 295 wells in this area. The center of the structure is
located about 0.75 miles northwest of the high school parking lot. The bed-
rock surface of the disturbed area is overlain by 75 to 200 feet of glacial
drift. Rocks as old as the Ordovician Oneota Dolomite (fig. 2) have been
brought to the bedrock surface near the center of the Disturbance.
Mississippi an and Pennsyl vanian strata have been thrust down and preserved in
some of the faulted blocks. These latter rocks have not been found in this
area any closer than 50 miles to the south of the Disturbance. As shown in
figure 5, strata appear to be horizontal around the periphery of the structure
and even within the individual faulted blocks, the strata appear to be only
si ightly til ted.
Figure 1.
PHYSIOGRAPHIC
DIVISIONS
OF
ILLINOIS
Reprinted 1978
! TILL PLAINS SECTION Jv
— t— r
GREAT LAKE
SECTION
Ozark Plateaus Province
Interior Low Plateaus Province
Central Lowland Province
Coastal Plain Province
System
or series
Stratigraphic
units and
thickness(f t )
Graphic
log
Rock type
Water-yielding
characteristics
PLEISTOCENE
Named in
figure 6
75 - 300
' . ° ■ • ,
Unconsolidated
glacial deposits,
loess, and alluvium
Water yields varied;
largest from thick out-
wash deposits in western
part of county
SILURIAN
Niagaran-Alex-
andrian
0 - 300
-/-/-,
Dolomite, silty at
base, locally
cherty
Yields moderate to large
supplies where creviced
and more than 50 ft. thick.
May contain oil, gas, HoS
'A/ /
1 / /
/-/A-/-
-/-/-/
ORDOVICIAN
Maquoketa
125 - 225
— ~ -
Shale, gray or brown;
argillaceous dolomite
Yields small supplies from
dolomite or fractured shale
I / 1 /
/ / / /
Galena-
Platteville
275 - 325
/ / 7 /
Dolomite, upper part
medium-grained, lower
part very fine grained
Yields small to moderate
supplies where creviced
/ / /
/ / /
/ / /
■ / / /
/ / /
Glenwood-
St. Peter
100 - 300
/ ./..-./.-.
Sandstone, fine to
coarse; thin dolomite
at top; red shale and
chert rubble at base
Yields moderate supplies
■ ~& ■
jA
CAMBRIAN
Potosi
50 - 100
/ / /
Dolomite, fine-grained
Yields small supplies
where creviced
/ / / .
1 / / f
I / / ,
/ / /
Franconia
50 - 75
J_ ■
Dolomitic sandstone
and shale
Generally not water-yield-
ing
J-
■' ^U
Ironton-
Galesville
150 - 200
-*--i.
Sandstone; upper part
dolomitic, lower part
well-sorted
Most productive bedrock
aquifer in county; yields
large supplies
Eau Claire
400 - 450
Siltstone, sandstone,
shale, and dolomite
Generally not water-yielding
1 1 1 1 1
Mt . Simon
1500 - 2200
Sandstone, coarse-to
medium-grained
Yields moderate amounts
of water; water quality
good at top but deterior-
ates with depth
PRECAMBRIAN
Granite
Not water-yielding
Figure 2. - Generalized column of geologic formations in Lake County,
Considerable discussion as to the origin of the Des Plaines Disturbance has
occurred for at least 60 years, with at least five different ideas proferred
at one time or another. The most plausible explanation suggests that the
structure was formed by a large meteorite impact during post-Pennsyl vanian
time. Following impact the rocks rebounded elastically past their initial
positions and the deformation became "frozen" by rupture of the rocks during
this recovery. Subsequently, an unknown thickness of Pennsyl vanian strata,
probably several hundred feet, and at least 700 feet of Mississippian strata
have been eroded from the area so that the current structure represents only
the "root" portion of the structure immediately after the impact. Additional
well samples collected within the last couple of years have included shatter
cones--conical , striated, fractured rock fragments generally believed to have
been formed by shock waves generated by meteorite impact.
The bedrock surface in northeastern
Illinois has been modified by the
Pleistocene glaciers that repeatedly
covered the area during the last
700,000 years. Some of the rills
and valleys in the bedrock surface
formed by pre-Pleistocene erosion
were accentuated by mel twater from
the early glaciers; however, many of
these valleys were later filled so
compl etely with glacial debris that
in many places no surface expression
of them is now visible and present-
day drainage does not, for the most
part, follow them. Bedrock
exposures show the well-developed
scratches, called striations, which
prove that the higher parts of the
bedrock surface were scraped,
rounded, and ground by the over-
riding glacial ice. Rock debris
entrained in the ice acted as a
giant piece of sandpaper. The ice
sheet itself was several thousand
feet thick and extremely heavy when
it crossed this region. Glacial
deposits, being relatively weak,
were easily eroded by each
succeeding glacier and became
incorporated into the newly forming
glacial material, called till, that
blankets the area. Till is a
mixture of rock fragments of many
types and sizes. The overall effect
of glaciation in this region has been to subdue the pre-Pleistocene topography
(also see attached "Pleistocene Glaciations in Illinois").
Figure 3. Location of the Kankakee Arch and
adjacent structures, Wisconsin Arch, Cincin-
nati Arch, Illinois Basin, and Michigan
Basin, in the north-central Midcontinent
Region. (From Reinertsen, 1979.)
Although Pleistocene glaciers have covered nearly 85 percent of Illinois at
one time or another during the past million years or so, no deposits
definitely identified as pre- 111 inoian have been found in northeastern
Illinois. Illinoian tills to the northwest, west, and southwest of the
Chicago area indicate that Illinoian glaciers did advance southward through
the Lake Michigan Basin and did cover this region. Subsequent weathering and
erosion, followed by Wisconsinan glaciation, obliterated all traces of
Illinoian glaciation from the field trip area.
Wisconsinan tills of the Woodfordian Substage deposited from about 12,000 to
14,000 years ago underlie this area; here the till of the Wedron Formation
ranges from less than 100 feet to more than 200 feet thick (fig. 6).
As the Woodfordian glacier melted, a series of lakes formed filling low areas
between the ice margin and the adjacent higher land of the end moraines
surrounding what is now the Lake Michigan Basin. Some of these lakes were
larger than present-day Lake Michigan, which was developed about 1,800 years
Chicago
Rockford
Figure4. Stylized north-south cross section shows the structure of the Illinois Basin. In order to
show detail, the thickness of the sedimentary rocks has been greatly exaggerated and the
younger, unconsolidated surface deposits have been eliminated. The oldest rocks are Pre-
cambrian (Pre-C) granites. They form a depression that is filled with layers of sedimentary
rocks of various ages: Cambrian (C), Ordovician (0), bilurian (S), Devonian (D), Mississip-
pian (M), Pennsyl vanian (P), Cretaceous (K), and Tertiary (T). The scale is approximate.
ago to its present level. The glacial deposits underlying the lakes have been
reworked by waves and currents; those deposits not inundated by the lakes have
been subjected to the wind and running water to produce the land forms seen
today.
Mineral Production
During 1984, the last year for which complete mineral production records are
available, of the 10? Illinois counties, 99 reported mineral production. The
total value of all minerals extracted from Illinois increased by 9.5 percent
to $3,138 billion. The total value of all minerals extracted, processed, and
manufactured in the state was more than $3.9 billion. Coal continued to be
the leading commodity in terms of value; oil ranked second; stone and sand and
gravel ranked third and fourth; fluorspar was fifth.
Nationally, Illinois ranked eighteenth in value of nonfuel mineral
production. It remained the principal U.S. producer of fluorspar, tripoli,
and industrial sand and led in the manufacture of iron-oxide pigments. In
stone and peat production, the state ranked fourth.
Mineral resources extracted from Cook County in order of value are: stone,
sand and gravel, peat, and groundwater. In addition, several mineral
RUE
R 12 E
500
1000
I500L
Dnft
> V>
p>s3
~Miss.f-
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-_— _r^r
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1 1
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— _ r~—
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- Moquoketo ~- —— —. — — _
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Galena -Plotteville
r
i
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Glenwood-St. Peter-
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1,1
Trempealeau -Franconia
—T~ — _
z-zTz-if'z:-
— — -
— -
11
n
r§
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j"~ Eau Claire -Mt. Simon
I
\\ 1
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1
VERTICAL EXAGGERATION: 10 X
Ft N
MILES
0
Drift
500
1000
I500L
Figure 5. - Geologic map and cross sections of the Des Plaines Disturbance (after
Emrich and Bergstrom, 1962).
materials that originate outside
the state are processed here; in
order of value they are:
expanded perlite, slag, pig iron,
and secondary slab zinc. Mineral
products manufactured here, in
order of value, are: lime, clay
products, and metallurgical
coke. Cook County mineral
extraction and processing had a
value of $111,040,000 for 1984,
which ranks 7th in the state
based on that value.
Mineral resources extracted from
Lake County in order of value
are: sand and gravel, peat, and
groundwater. In addition,
several mineral materials that
originate outside the state are
processed here; in order of value
they are: calcined gypsum, crude
iodine, and columbium. Clay
products are manufactured here.
Lake County mineral extraction
and processing had a total value
of $10,272,000 for 1984, which
ranked it 43rd based on that
val ue.
TIME
UNITS
ROCK
UNITS
SERIES
STAGE
SUBSTAGE
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Figure 6. Geological classification and field relations of surficial
materials in Lake County. Symbols for rock units are those used on
plate 1.
The close proximity of sand and gravel and peat pits to the large market area
in northeastern Illinois greatly reduces the shipping costs of these high-bulk
materials. To conserve construction materials, long-range planning is
necessary so that future pit sites having thin overburden do not become
covered and lost to housing developments and shopping centers.
Abundant groundwater and surface water supplies are readily available in the
Chicago area. It would be extremely difficult, if not impossible, to place
values on them. Thus, although they are included in the list of mineral
resources extracted for both counties, no monetary value was assigned to
them. They probably should be listed as first in value for both counties,
however.
Water Resources
Part of the precipitation striking the Earth's surface percolates downward
into the open spaces in unconsolidated earth materials and the underlying
bedrock strata. The open spaces range in size from minute pores to open
joints and cracks and large crevices. Rocks are saturated with water below a
certain depth and form the groundwater reservoir, the top of which is commonly
called the "water table." Aquifers are earth materials that contain water and
readily yield it to wells.
The aquifers of Lake and Cook Counties have supplied large quantities of water
for industrial, metropolitan, and domestic needs for many years. There are
two major water-yielding systems: the shallow system, consisting of the
glacial drift aquifers and the shallow Silurian dolomite aquifer; and the deep
sandstone system, consisting of the Ordovician Glenwood-St. Peter Sandstone
and the Cambrian Ironton-Gal esvill e Sandstone and the Mt. Simon Sandstone.
The shallow aquifer system is recharged by local rainfall; the deeper aquifer
system by precipitation seeping downward through overlying rocks in the west
and southwest in McHenry, Boone, De Kal b and Kane Counties. However, the
rapid development of the Chicago region has severely overtaxed the capacity of
the deep aquifers in the region. Water levels in deep wells in the region
have declined as much as several hundred feet, indicating that the groundwater
resource is being "mined"--extracted faster than it can be replaced by natural
recharge.
Contrary to popular myth, the groundwater reservoir in Illinois is not
recharged with water from Lake Superior.
Although groundwater resources are available throughout Lake and Cook
Counties, abundant quantities of good quality water in the field trip area
occur mainly in the deep aquifer system. However, in some parts of Kane and
westernmost Cook Counties, these deep aquifers contain naturally occurring
quantities of dissolved barium and/or radium that exceed the USEPA drinking
water standards. Geological Survey scientists are using seismic and
electrical earth resisitivity geophysical methods to locate new groundwater
resources in the shallow glacial materials to supplement and dilute the
groundwater produced from the deep aquifers for communites in these areas. It
is more imperative now than ever before that we protect our groundwater
supplies from contamination and from overuse, so that adequate supplies of
good quality water will be available in the future.
Several communities along the east edge of the county draw their water
supplies from Lake Michigan. Lake County municipalities withdraw about 50.4
million gallons of water per day (mg/d). A 1966 U.S. Supreme Court ruling set
a limit on the amount of water that Illinois communities could withdraw from
the lake 3,100 cubic feet per second (a cubic foot of water equals 7.5
gallons) for water supply and for diversion for the Chicago Sanitary and Ship
Canal. Most of the diverted water (3,100 cubic feet per second) has been
preempted by the City of Chicago and the Metropolitan Sanitary District. Only
100 cubic feet per second (64.6 mg/d) are left from the State's allotment for
other Illinois users. Lake County has filed a report with the State noting
that by the year 2000 the county will need 32.8 percent more water from Lake
Michigan than it is now diverting. Interestingly enough, the current Chicago
usage of lake water is estimated to draw down the lake level only about 0.5
inch annually!
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A GUIDE TO THE ROUTE
Line up along the north side of the parking area; not in the driveway, but in
the parking area on the east side of Main East Township High School. Mileage
figures begin at the exit from the parking lot. NOTE: You are on your own to
get to Stop 1. Obey all traffic lights, signs, and directions.
TURN LEFT (north) on Dee Road and prepare to turn
left at the stoplight.
CAUTION: STOP LIGHT - Dempster Street (U.S. 14).
TURN LEFT (west). Use EXTREME CAUTION. Stay in
the inside lane.
0.25 0.3- CAUTION: STOP LIGHT - Potter Road. CONTINUE AHEAD
(west).
Enter the City of Des Plaines.
Underpass: Tri-State Toll road (Interstate 294).
CONTINUE AHEAD.
CAUTION: STOP LIGHT - Rand Road/Northwest
Highway. CONTINUE AHEAD (west).
Des Plaines River to the right. CONTINUE AHEAD.
Prepare to turn left.
TURN LEFT (southeast) on Busse Highway. This is a
lop-sided T-road intersection: no stoplights or
stop signs. USE EXTREME CAUTION.
0.9- 2.3+ TURN LEFT with caution into Belleau Lake Forest
Preserve and park.
0.05 2.35+ STOP 1. Discussion of valley train deposits at
Belleau Lake Forest Preserve.
0.0 2.35+ Leave Stop 1.
0.05 2.4+ CAUTION: reenter Busse Highway. TURN LEFT
(southeast).
0.1 2.5+ Underpass: Tri-State Tollroad.
0.35 2.85+ CAUTION: STOP LIGHT - Potter Road. This is a T-
road and a curve. Do NOT turn onto Potter Road.
CONTINUE AHEAD with a curve on Busse Highway
(southeast).
0.2+ 3.1- CAUTION: STOP LIGHT - Oakton Street. TURN LEFT
(east).
0.1
0.4-
0.3+
0.7 +
0.15-
0.85
0.4+
1.25 +
0.15
1.4+
Explanation of letters on the
following route maps
c = Cahokia Alluvium
g = Grayslake Peat (and muck)
pi = Parkland Sand (dunes, etc.)
Ip = lake plain
ed = Dolton Member of Equality Formation
(shallow-water, near-shore sediments:
beaches, bars, spits, and deltas)
hm = Mackinaw Member of Henry Formation
(sand and gravel; valley train deposits)
Lake Border Morainic System
zi = Zion City Moraine
hp = Highland Park Moraine
b = Blodgett Moraine
d = Deerfield Moraine
pr = Park Ridge Moraine
Ibg = Lake Border Groundmoraine
tg = Tinley Groundmoraine
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Miles to
Miles from
next point
start
0.05 +
3.15 +
0.15 +
3.35
CAUTION: STOP LIGHT - Dee Road. CONTINUE AHEAD
(east) on Oakton.
CAUTION: STOP LIGHT - Rand Road/Northwest
Highway. CONTINUE AHEAD (east) and cross Tinley
Ground Moraine.
0.55+ 3.9+ CAUTION: STOP LIGHT - Greenwood Avenue. CONTINUE
AHEAD (east) and ascend gentle frontal slope of
Park Ridge Moraine.
0.55+ 4.45+ CAUTION: STOP LIGHT - Prospect Avenue. TURN LEFT
(north); near crest of Park Ridge Moraine.
0.1 4.55+ CAUTION: Y-intersection. BEAR RIGHT (northeast).
0.3 4.85+ STOP: 2-way. TURN LEFT (north) on Washington
Street.
0.2 5.05+ Park along side of Washington Street. Do NOT
block driveways. CAUTION: watch traffic.
STOP 2. Discussion of Lake Border Morainic System.
Leave Stop 2. CONTINUE AHEAD (north).
TURN RIGHT (east) on Main Street.
CAUTION: STOP LIGHT - Milwaukee Road (State Route
[SR] 21). TURN RIGHT (southeast).
0.55+ 5.95+ CAUTION: STOP LIGHT - Oakton Street. TURN LEFT
(east) and descend gentle backslope of the Park
Ridge Moraine. Stay in INSIDE LANE.
CAUTION: STOP LIGHT - Harlem Avenue (SR 43)
CONTINUE AHEAD (east) and prepare to turn left.
CAUTION: STOP LIGHT - Waukegan Road. TURN LEFT
(north) into outside lane on SR 43.
CAUTION: just beyond the left turn, TURN RIGHT
into the parking area.
STOP 3. Discussion of ancient Lake Chicago
0.0 6.6+ Leave Stop 3. TURN RIGHT (north) on Waukegan Road
and drive along the approximate position of the
Glenwood Shoreline.
0.0
5.05 +
0.05
5.1 +
0.25 +
5.35 +
0.4
6.35 +
0.2+
6.55 +
0.05-
6.6+
Miles to
Miles from
next point
start
0.5-
7.1-
0.2+
7.3
Enter Morton Grove.
CAUTION: STOP LIGHT - angle intersection with
Caldwell Avenue (U.S. 14). BEAR LEFT (north). Get
in the OUTSIDE LANE.
0.3+ 7.6+ CAUTION: STOP LIGHT - Dempster Street (SR 58).
TURN RIGHT (east).
0.1+ 7.7+ CAUTION: STOP LIGHT - Entrance to shopping center
on the right. CONTINUE AHEAD down across the lake
plain.
0.4+ 8.15- CAUTION: STOP LIGHT - Lehigh Avenue. CAUTION:
Just beyond are two guarded tracks on the S00
Railroad. CONTINUE AHEAD (east) and cross the
North Branch of the Chicago River.
Ferris Avenue. CONTINUE
0.2-
8.3+
CAUTION:
AHEAD.
STOP LIGHT
0.1 +
8.45 +
CAUTION:
AHEAD.
STOP LIGHT
0.3+
8.75 +
CAUTION: STOP LIGHT
AHEAD (east).
0.25
9.0+
CAUTION:
AHEAD.
STOP LIGHT
0.25
9.25 +
CAUTION:
STOP LIGHT
0.15 +
9.45
0.2-
9.65-
0.15
9.8-
0.25 +
10.05
Austin Avenue. CONTINUE
Menard Avenue. CONTINUE
is the interchange for Interstate 94. CONTINUE
AHEAD (east) on Dempster. This interchange is
located on one of the fingers of the Wilmette Spit.
Overpass of I 94. CONTINUE AHEAD (east).
CAUTION: STOP LIGHT - Lockwood Avenue. CONTINUE
AHEAD and prepare to turn left.
CAUTION: STOP LIGHT - Gross Point Road. TURN LEFT
(northeast).
CAUTION: Chicago and Northwestern (C & NW)
Railroad crossing, 1-track guarded. CONTINUE AHEAD
along the Wilmette Spit, a near shore lake deposit
formed during Glenwood time.
Miles to
Miles from
lext point
start
0.35 +
10.4+
0.15
10.55+
0.5 +
11.1-
CAUTION: STOP LIGHT - Church Street. CONTINUE
AHEAD (northeast) on Gross Point Road.
CAUTION: STOP LIGHT - Skokie Boulevard. CONTINUE
AHEAD (northeast) on Gross Point Road.
CAUTION: STOP LIGHT - Golf Road (Simpson). TURN
LEFT (west) and move toward the outside lane. To
the right, after the turn, is the Rush North Shore
Medical Center. This site used to be a large
gravel pit; an example of sequential land use.
CAUTION: STOP LIGHT - Skokie Road (U.S. 41). TURN
RIGHT (north).
CAUTION: STOP LIGHT. CONTINUE AHEAD (north). Old
Orchard Shopping Center to the left.
CAUTION: STOP LIGHT. CONTINUE AHEAD.
CAUTION: STOP LIGHT. CONTINUE AHEAD.
CAUTION: STOP LIGHT - Old Orchard Road (Harrison
Street). CONTINUE AHEAD (north).
Enter Wilmette.
CAUTION: STOP LIGHT - Old Glenview Road. TURN
RIGHT (east). You are ascending a gravel hill that
is capped by sand eastward.
0.3 12.45 Alongside the golf course the soil is quite
sandy. Not all of the hills to the right are
artificial; some are small dunes that have been
grassed over and stabilized.
0.45+ 12.95- CAUTION: TURN LEFT at the east entrance (third
from west) to Centennial Park of the Wilmette Park
District. Do NOT block driveways when parking,
then walk a short distance north along the east
side of the swimming pool and down a slope to a
garden area.
STOP 4. Discussion of Parkland Sand and nearby
dunes.
0.0 12.95- Leave Stop 4 and TURN LEFT (easterly) on Old
Glenview Road.
0.35
11.45-
0.1 +
11.55
0.15-
11.7-
0.15 +
11.85+
0.05 +
11.9+
0.15 +
12.1-
0.05 +
12.15 +
Miles to Miles from
next point start
0.05+ 13.0- CAUTION: STOP LIGHT - Crawford Avenue. TURN RIGHT
(southeasterly). Move to the inside lane as you go
south.
0.3+ 13.3+ CAUTION: STOP LIGHT - Gross Point Road. CONTINUE
AHEAD (southeasterly) on Crawford and prepare to
turn left just beyond Gross Point Road. Ahead is
the pronounced frontal slope of the Wilmette Spit
formed during the Glenwood II Phase (12,900-12,700
BP).
0.05- 13.35+ CAUTION: STOP LIGHT - Central Street. TURN LEFT
(east). Coming down the Glenwood Shoreline onto
the lake plain.
0.1+ 13.5- Outer lower edge of Wilmette Spit during the
Calumet Phase.
0.35+ 13.85+ CAUTION: STOP LIGHT - Central Park Avenue.
CONTINUE AHEAD across the lake bottom during the
Calumet Phase.
0.1+ 14.0- CAUTION: STOP LIGHT - Lincolnwood Drive. CONTINUE
AHEAD (east).
0.35+ 14.35+ CAUTION: STOP LIGHT - McDaniel Street. CONTINUE
AHEAD.
0.25- 14.6- CAUTION: Hartrey Avenue, T-Street. CONTINUE AHEAD
(east).
0.25- 14.8+ CAUTION: STOP LIGHT - Green Bay Road. CONTINUE
AHEAD under C & NW railroad tracks.
0.25+ 15.05+ CAUTION: STOP LIGHT - Ashland Avenue. CONTINUE
AHEAD. Dyche Stadium, Northwestern University to
the left.
0.25- 15.3+ CAUTION: STOP LIGHT - Asbury Avenue. CONTINUE
AHEAD (east).
0.1 15.4+ Cross the North Shore Channel constructed to
conduct lake water southward to augment flow in the
lower part of North Branch Chicago River.
0.1- 15.5+ CAUTION: Rapid Transit overpass and STOP LIGHT -
Gerard Avenue. CONTINUE AHEAD (east) and ascend
Rose Hill Spit formed during the Calumet Phase
(11,800-11,200 BP).
0.1
16.0+
0.1 +
16.15-
0.15 +
16.3
Miles to Miles from
next point start
0.1+ 15.6+ CAUTION: STOP LIGHT - Ridge Avenue. TURN LEFT
(northeasterly).
0.1+ 15.7+ Evanston Hospital to the left. CONTINUE AHEAD.
The side streets to the right look down to the lake
side of the Rose Hill Spit. The base is the
approximate position of the Toleston Shoreline
formed during the Nipi ssing I Phase (4,500 BP).
0.2 15.9+ CAUTION: STOP LIGHT - Isabella Street. CONTINUE
AHEAD (north) on Sheridan Road.
National College of Education to left.
Enter Wilmette.
Bahai Temple to left. CONTINUE AHEAD around the
curve and descend the back slope of the Rose Hill
Spit.
0.15 16.45 Cross the North Shore Channel.
0.05+ 16.5+ CAUTION: TURN RIGHT on Michigan Avenue. CONTINUE
TURN TO RIGHT into Gill son Park. Keep to the right
past the Coast Guard Station and the Sheridan Shore
Yacht Club.
0.05+ 16.55+ Wilmette Coast Guard Station to the right.
0.25- 16.8 STOP 5. Lunch and discussion of some of the
lakeshore features in the southern part of the
field trip area near Wilmette Harbor.
0.0 16.8 Leave Stop 5 and CONTINUE AHEAD (westerly) on the
park drive.
0.15+ 16.95+ STOP: 1-way, T-road intersection. TURN LEFT and
ascend dune. You will encounter several drives
from the left, none of which you can legally turn
into so continue winding to the right until you get
to the park exit.
0.15 17.1 STOP: 2-way, crossroad - Michigan Avenue.
CONTINUE AHEAD (southwest) on Washington Avenue.
0.05+ 17.15+ STOP: 3-way, 5-point intersection. TURN RIGHT
(northwest) on Sheridan Road.
ILUNCHI
jssO Light
Wilmette Harbor
Miles to Miles from
next point start
0.15
0.7
0.2+
0.4+
0.15 +
0.15-
0.1 +
0.25
17.3+
18.0+
18.25
18.65+
18.85+
0.05 +
18.9+
0.3+
19.25
0.15 +
19.4+
0.05
19.45+
19.6+
19.75
20.0
0.25
20.25
0.3-
20.5 +
0.5 +
21.05-
0.5
21.55-
0.3+
21.85+
0.7-
22.5 +
CAUTION: STOP LIGHT - Lake Avenue. CONTINUE AHEAD
(northwest).
CAUTION: STOP LIGHT - Westerfield Road. CONTINUE
AHEAD (northwest).
Enter Kenilworth at the stone piers
CAUTION: STOP LIGHT - Kenilworth Avenue. CONTINUE
AHEAD (northwest).
Winnetka Avenue - TURN LEFT (southwest). Not well
marked - no stoplight or stop sign.
BEAR RIGHT (west).
New Trier High School to right.
C & NW Railroad underpass. CONTINUE AHEAD.
CAUTION: STOP LIGHT - Green Bay Road. CONTINUE
AHEAD (west) ascending the rather steep sea cliff
of the Highland Park Moraine, the source of
sediment for the Wilmette Spit 0.25 miles south.
STOP: 3-way; T-road. TURN RIGHT (north) on Church
Road.
STOP: 3-way; T-road. TURN LEFT on Hill Road.
CAUTION: crossroad. BEAR LEFT at angle and
descend Hill Road across the front of the Highland
Park Moraine.
BEAR RIGHT (west) on Hill Road/Winnetka Road.
STOP: 4-way. CONTINUE AHEAD (west).
CAUTION: STOP LIGHT - Hibbard Road. TURN RIGHT
(north).
CAUTION: STOP LIGHT - Willow Road. CONTINUE AHEAD
(north).
CAUTION: STOP LIGHT - Elm Street. CONTINUE AHEAD
(north).
STOP: 3-way; T-road. TURN LEFT (west) on Tower
Road.
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Miles to Miles from
next point start
0.8- 23.3+ STOP: 4-way. TURN LEFT (south) on Forest Way.
This is the area of the Skokie Lagoons. The area
to the northwest for a short distance is underlain
by muck and peat materials.
1.05+ 24.35+ STOP 6. Skokie Lagoon and discussion of lake plain
sediments deposited during Glenwood Lake levels.
0.0 24.35+ Leave Stop 5 and CONTINUE AHEAD (south).
0.2 24.55+ STOP: 1-way; T-road intersection with Wil low
Road. TURN RIGHT (west) on Willow Road and enter
Northfield.
0.1+ 24.65+ Cross Skokie River.
0.05- 24.7+ CAUTION: STOP LIGHT - Lagoon Drive. CONTINUE
AHEAD (west).
0.4+ 25.1+ Overpass Interstate 94. CONTINUE AHEAD (west).
0.15+ 25.25+ CAUTION: STOP LIGHT - Central Avenue. CONTINUE
AHEAD.
0.05- 25.3+ CAUTION: Single C & NW railroad track. CONTINUE
AHEAD.
0.05+ 25.35+ CAUTION: STOP LIGHT - Old Willow Road. CONTINUE
AHEAD (west).
0.05+ 25.45 Cross North Branch of Chicago River.
0.35- 25.8- CAUTION: STOP LIGHT - Wagner Road. CONTINUE AHEAD
(west).
0.6- 26.4- CAUTION: STOP LIGHT - Sunset Ridge Road. CONTINUE
AHEAD (west) and ascend the back slope of the
Deerfield Moraine.
0.45 26.85- CAUTION: STOP LIGHT - Waukegan Road. This is the
crest of the Deerfield Moraine. CONTINUE AHEAD
(west) and descend the frontal slope of the
Deerfield Moraine.
0.25+ 27.1 Approximate boundary between Deerfield Moraine and
Glenwood lake plain sediments.
0.0
27.2
0.2+
27.4+
0.1 +
27.55-
0.1 +
27.65
0.2+
27.85
Miles to Miles from
next point start
0.1 27.2 CAUTION: PARK on road shoulder. DO NOT walk or
stand on Willow Road - fast traffic.
STOP 7. Discussion of sanitary landfills.
CAUTION: leave Stop 7 and reenter Willow Road.
Cross West Fork North Branch of Chicago River.
CAUTION: entrance to Lake Landfill on right.
Watch for cross traffic and CONTINUE AHEAD (west).
CAUTION: STOP LIGHT - Old Willow Road. CONTINUE
AHEAD.
S00 Railroad overpass. Glenview Naval Air Station
to left at 10 o'clock.
0.2- 28.05 CAUTION: flashing runway approach lights to left
and possibility of large, low-flying aircraft. DO
NOT STOP. CONTINUE AHEAD (west) across Park Ridge
Groundmoraine.
0.2+ 28.25+ C & NW Railroad underpass
0.1+ 28.4- CAUTION: STOP LIGHT - Shermer Road. CONTINUE
AHEAD (west) up the gentle back slope of the Park
Ridge Moraine. This is a wider moraine than the
other lake border moraines in this vicinity.
0.5+ 28.9 CAUTION: STOP LIGHT Greenwood Road. CONTINUE
AHEAD.
0.5 29.4 CAUTION: STOP LIGHT - Pfingsten Road. TURN RIGHT
(north). Note the gentle undulating swell and
swale topography for the next couple of miles--it
is partly masked by homes.
0.25 29.65 Enter Northbrook. The crest of the Park Ridge
Moraine is higher than 685 feet mean sea level
(msl ) about 0.5 miles to the west.
0.5 29.4 CAUTION: STOP LIGHT - Techny Road. CONTINUE AHEAD
(north).
0.35+ 30.5+ CAUTION: STOP LIGHT - Koepke Road. CONTINUE
AHEAD.
r/2km
Miles to
Miles from
next point
start
0.4-
30.9
0.25-
31.15-
0.5 +
31.65
0.5
32.15
CAUTION: STOP LIGHT - Walters Avenue. CONTINUE
AHEAD (north).
CAUTION: STOP LIGHT - Cherry Lane. CONTINUE AHEAD
(north).
CAUTION: STOP LIGHT - Dundee Road. CONTINUE AHEAD
(north) across Park Ridge Groundmoraine.
CAUTION: STOP LIGHT - Maria Avenue. To the right
the Underwriter's Laboratory, Inc. is situated on
the site of an old abandoned clay pit; another
example of sequential land use.
0.25+ 32.4+ Toll road feeder overpass.
0.2+ 32.65 CAUTION: STOP LIGHT - Lake/Cook Road. TURN RIGHT
(east) and cross West Fork North Branch Chicago
River.
0.05+ 32.7+ To the left, the restaurant-office building complex
is located on another abandoned clay pit site.
CAUTION: STOP LIGHT. CONTINUE AHEAD (east).
CAUTION: S00 Railroad crossing - 2 tracks.
CAUTION: STOP LIGHT entrance to Lake Cook Shopping
Plaza. We are ascending the Deerfield Moraine.
0.15+ 33.3 CAUTION: STOP LIGHT - Waukegan Road. CONTINUE
AHEAD (east).
Crest of the Deerfield Moraine, 680+ feet msl .
Enter Northbrook and descend backslope of Deerfield
Moraine.
CAUTION: STOP LIGHT. CONTINUE AHEAD.
Cross North Branch Chicago River. Note gauging
station on east side about 100 feet south of our
route.
0.05+ 34.25- CAUTION: STOP LIGHT. CONTINUE AHEAD (east) and
ascend the Blodgett Moraine.
0.1-
32.8
0.15 +
32.95+
0.15-
33.1+
0.1
33.4
0.4+
33.8+
0.2
34.0+
0.15
34.15+
Miles to Miles from
next point start
0.15 +
34.4
0.1
34.5
0.15
34.65
0.1 +
34.75+
0.1 +
34.9
0.1 +
35.0+
0.1-
35.1 +
0.05 +
35.15+
0.6
35.3+
0.1 +
35. 4 +
0.05-
35.45+
0.1
35.55+
0.3
35.85+
0.2
36.05+
Crest of the Blodgett Moraine, 660+ feet msl .
CAUTION: STOP LIGHT. CONTINUE AHEAD (east).
CAUTION: STOP LIGHT - Ridge Road/Lee Road.
CONTINUE AHEAD.
CAUTION: STOP LIGHT. CONTINUE AHEAD.
CAUTION: C & NW Railroad; 2-tracks guarded.
CONTINUE AHEAD.
CAUTION: STOP LIGHT - Skokie Boulevard. CONTINUE
AHEAD (east).
CAUTION: STOP LIGHT - entrance to Edens Expressway
(U.S. 41).
Edens Expressway overpass. Area underlain by
Glenwood lake plain sediments.
CAUTION: STOP LIGHT - exit from Edens Expressway
CONTINUE AHEAD (east) and cross muck and peat area.
Cross Skokie River.
Chicago Botanic Gardens to the right.
Cross area underlain by Glennwood lake plain
sediments.
Cross Blodgett Groundmoraine.
Ascend sharp frontal slope of Highland Park
Moraine.
0.2
0.05 +
0.2 +
0.2+
36.25+ CAUTION: STOP LIGHT - Green Bay Road. CONTINUE
AHEAD.
36.3+ Crest of Highland Park Moraine, 685+ feet msl.
36.5+ CAUTION: C & NW Railroad; 2-tracks guarded.
CONTINUE AHEAD (east).
36.75+ CAUTION: STOP LIGHT - Sheridan Road. TURN HARD
LEFT and enter Lake County. Route to north crosses
a number of stone bridges over narrow, deep
ravines.
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iles from
next point
start
0.7 +
37.45 +
0.4-
37.85+
0.1-
0.1
0.0
37.95+
38.05+
38.05 +
0.2
38.25
0.1 +
38.35+
0.1 +
38.45+
0.15-
38.6
STOP: 4-way. TURN RIGHT (north) on Sheridan Road.
TURN RIGHT (east) on Roger Williams Drive. This is
just beyond the sign pointing to the Ravinia
Business District.
Crossing a \/ery deep ravine. CONTINUE AHEAD.
TURN LEFT (north) into the Rosewood Park and Beach
Parking area. Park your car and walk west to the
bridge over the ravine.
STOP 8. Discussion of drainage problems in this
area.
Leave Stop 8 and retrace route west to Sheridan
Road.
STOP: 2-way; Sheridan Road. TURN RIGHT (north).
Descend hill and prepare to turn right.
TURN RIGHT downhill toward Rosewood Beach.
Lower Rosewood Beach parking area.
STOP 9. Discussion of the bluff geology and its
attendant problems for North Shore communities.
END OF FIELD TRIP
FIELD TRIP STOPS
NOTE: The numbers in parentheses following the topographic map name,
(42087A7), is the code assigned to that map as part of the National
Mapping Program. The state is divided into 1° blocks of latitutde and
longitude. The first pair of numbers refers to the latitude of the
southeast corner of the block and the next three numbers designates the
longitude. The blocks are divided into 64 7.5-minute quadrangles; the
letter refers to the east-west row from the bottom and the last digit
refers to the north-south row from the right.
STOP 1. Discussion of valley trains deposits along the Des Plaines River at
Belleau Lake, Cook County Forest Preserve. TParking area: N 1/2 NE
1/4 SE 1/4 Sec. 21, T. 41 N., R. 12 E., 3rd P.M., Cook County; Park
Ridge 7.5-minute Quadrangle (42087A7)!.
We are located about 0.4 miles east of the Des Plaines River, a relatively
small stream that originates in Wisconsin and flows southward roughly
paralleling the Lake Michigan shoreline. Forty miles south at the State Line,
it lies along the west side of the Park Ridge Moraine. In its joruney
southward for the next 20 miles, it cuts back and forth across low sags in the
Park Ridge and Deerfield Moraines, finally emerging along the west side of the
Park Ridge Moraine to flow across the Tinley Groundmoraine about 13 miles
north of this location. Except in its lower course, where it occupies a
channel through the Tinley Moraine and Valparaiso Morainic System, the Des
Plaines River hardly has a valley. That, is, it is not flowing in a well-
defined, entrenched valley. Its gradient, bed slope, is less than two feet
per mile from the State Line to this locality. The straight-line distance
from here to the south-southwest, where it joins the Kankakee River to form
the Illinois River, is about 50 miles.
Sometime after the Deerfield Moraine formed, large volumes of meltwater laden
with vast amounts of outwash material (gravel, sand, and silt) from the waning
glacier coursed southward through this area. As the volume of meltwater
diminished, the stream was no longer able to transport this heavy load, and
left it behind along its course as valley train deposits (see PLEISTOCENE
GLACIATIONS IN ILLINOIS in back). The deposits are mostly gravel in the
north, becoming finer-grained southward. Where mined, they have been well
sorted and well laminated. The valley train deposits are 1/3 to as much as
1.5 miles wide and are 25 to 30 feet thick. The valley train deposits end
about 7.5 miles downstream from here near Franklin Park, where the early Des
Plaines River debouched into Lake Chicago. This is the only stream in the
field trip area that contains valley train deposits and they have been the
basis for a viable construction aggregate industry. Belleau Lake was formed
when the valley train deposits here were removed for construction purposes.
STOP 2. View of surface of Lake Border Morainic System across from Mary Hill
Cemetery. TWest edge NW 1/4 NW 1/4 NW 1/4 SW 1/4 Sec. 24, T. 41 N.,
R. 12 E., 3rd P.M., Cook County; Park Ridge 7.5-minute Quadrangle
(42087A7)].
We are standing on the farthest west, the outer, Lake Border Morainic System
member, the Park Ridge Moraine. This system occurs east of the Des Plaines
River essentially in the northern part of the Metropolitan area. Five
moraines are recognized in this system: from west to east (oldest to
youngest) they are the Park Ridge, Deerfield, Blodgett, Highland Park, and
Zion City. Except for the detached segment of the Park Ridge Moraine that
forms Blue Island in the south suburban area, these moraines die out at the
lake plain, which we will see shortly. Continuations of these moraines,
however, are found in Indiana and Michigan so that the system forms a loop
around the margin of Lake Michigan. Sags between the moraines are distinct in
the field trip area, but to the north a short distance the separate moraines
are not as easily separated and recognized. Total maximum width of the Lake
Border Moraines in Illinois is about 7.5 miles.
The Park Ridge Moraine is the oldest and widest of the Lake Border Moraines,
being nearly two miles wide at a maximum. It extends the farthest south into
the lake plain, nearly 9.5 miles south from here, terminating in Elmwood
Park. For the most part, this moraine has a more suhdued surface relief and
more gentle slopes than other moraines in the Chicago region. Karnes, eskers,
and small lakes are not common across its surface. The gently undulating
surface is perhaps less disturbed and more open to view across Mary Hill
Cemetery than elsewhere nearby. Later at other localities on the field trip,
you will have the opportunity to see small areas of the moraine that are
relatively undisturbed. The large amount of construction in the region will
obscure and obliterate these small areas before long.
The moraine is made of a gray, clayey till that has a relatively low content
of pebbles, cobbles, and boulders. This is the material into which the
foundations and basements are being dug in this area. This till belongs to
the Wadsworth Member of the Wedron Formation.
STOP 3. Discussion of Lake Chicago and some of its physical features. TSW
cor SE 1/4 SE 1/4 SW 1/4 SW 1/4 Sec. 19, T. 41 N., R. 13 E., 3rd
P.M., Cook County; Park Ridge 7.5-minute Quadrangle (42087A7)].
Lake Michigan, as we know it, developed about 2500 years BP (before present).
Prior to that time, the Lake Michigan basin was occupied by a series of lakes
of different sizes and levels formed during and after late Wisconsinan
deglaciation from about 15,000 to 11,000 years BP. The record of these lakes
is found in the deposits and elevations of abandoned shoreline features (wave-
cut cliffs, beaches, spits, deltas) and abandoned outlets. We will see some
of these features on this field trip. Adjustments in the Earth's crust have
influenced the various lakes and associated features. We know that the crust
was depressed by the great weight of the overlying massive continental
glaciers; it is still slowly rebounding in some areas of the world from
Pleistocene events. The southern Lake Michigan basin, however, appears to
have been affected least by this crustal depression. The chronology of events
in the Lake Michigan basin is shown in figure 7.
Hansel and others (1985) noted that glacial and postglacial lake levels
changed because of several mechanisms: (1) advance and retreat of ice margins
that blocked or uncovered outlets, (2) downcutting of outlets, (3) major
increases and decreases in the volume of water entering the lakes, and (4)
differential isostatic changes in the altitudes of parts of the basin or
outlets. Generally, these mechanisms worked in combination to control events.
Figure 7. Chronology in the Lake Michigan basin. Shaded area indicates times inlets and outlets were used.
Radiocarbon ages are estimates (from Hansel et al., 1985).
Minor readvances of the glacier occurred between about 15,500 and 13,500 years
BP to form the Valparaiso, Tinley, and Lake Border Moraines. Following the
formation of at least the Valparaiso and the attendant ice-front melt-back,
some earlier workers felt that there may have been earlier, higher lake levels
in the southern part of the Lake Michigan basin. If this were the case,
however, much of the evidence for these events appears to have been obscured
or destroyed by the Tinley readvance.
During the formation of the Lake Border Moraines and as the ice margin melted
northward, 14,000 to 13,600 years BP, Lake Chicago formed behind the Tinley
and older moraines. Orainage for Lake Chicago was to the southwest, through a
pair of spillway channels, the Des Plaines and Sag Channels (fig. R). The
early high levels of this lake occurred during the Glenwood I phase between
14,000 and 13,600 years BP when the lake stood at about 640 feet msl (fig.
9). Following this initial high stand of Lake Chicago, the ice margin melted
northward to about the position of the Straits of Mackinac and drainage of the
lake shifted to the east. The lake was lowered considerably below present
Lake Michigan (580 feet, approximate msl) from 13,300 to 13,000 BP. With a
southward readvance of the glacier, the outlet to the east was blocked and
Lake Chicago rose to about 640 feet msl again, during the Glenwood II phase
(12,900 to 12,700 years BP) .
We are standing on the Glenwood shoreline that here was impinging on the
backslope of the Park Ridge Moraine. To the east the surface slopes down to
the flat Glenwood lake bottom. We will follow part of this shoreline to the
north then turn east across the lake plain to another feature of the Glenwood
lake level, the Wilmette Spit.
STOP 4. Examination of the Parkland Sand and discussion of the Wilmette
Spit. [Parking area: NE 1/4 SE 1/4 NE 1/4 SE 1/4 Sec. 32, T. 42 N.,
R. 13 E., 3rd P.M., Cook County; Evanston 7.5-minute Quadrangle
(42087A6)].
The area north-northeast from Morton Grove to Winnetka has the best developed
Glenwood lake level features in the Chicago region. Bretz (1955) noted that
the Glenwood shoreline shows nearly 30 miles each of sea cliffs and beaches in
this area, nineteen miles of which are spits that formed offshore. Wave
erosion at this time appears to have been more intense than any time since.
The Glenwood sea cliff intersects the Lake Michigan wave-cut cliff along the
east side of the Highland Park Moraine about three miles to the north. The
Glenwood sea cliff extends south through Winnetka for about 1.5 miles, its
southern tip located at the Indian Hills Golf Club, about 1.5 miles to the
north-northeast. During the Glenwood phases, the Highland Park Moraine
extended considerably farther east than now (fig. 10). Waves cut into the
moraine to form a cliff and currents swept the debris southward along the
cliff to build a large rounded sand and gravel deposit for about six miles off
the moraine's southern tip. The east side of the spit is a smooth arc sweep-
ing to the southwest, but the western side is digitate with nine westerly
extending "fingers" which are successively from north to south on the Glenwood
lake bottom.
Figure 8. Map of reference area (type area) for Lake Chicago and Glenwood. Calumet, and Toleston
beaches. Modified from Alden (1902), Schneider and Keller ( 1970), and Willman (1971). Numbers
refei to locations of radiocarbon dates listed in Table I. (from Hansel et al., 1985)
For the last 3.5 miles you have been travell
the crest of the Wilmette Spit or across sma
Glenwood time. Wind-blown sand mantles this
ized by the sod cover. The sand was derived
sand is exposed in garden plots along the no
You will note that it is well sorted, that i
unifomly medium-grained in size. The sand a
amount of organic material here, which gives
as the Parkland Sand, a wind-blown deposit,
age.
ing across the western slopes or
11 segments of lake bottom during
hilltop, but it is well stabil-
from nearby beach deposits. The
rth side of the swimming pool.
s, the sand grains are all fairly
ppears to contain a considerable
it a gray color. This is known
that is Wisconsinan to Holocene in
d. Glenwood II phase
g. Kirkfield phase
LAKE
SAGINAW
LAKE
CHICAGO
LEVEL Glenwood'
OUTLET Chicago
TIME Retreat from Lake Border Moraines I13.600BPI
b. Glenwood I phase
LEVEL Below todav
OUTLET indan River lowland, then Straits
TIME Twocreekan {12.000-11.800 BP)
e. Two Creeks low phase
LEVEL Chippewa Low
OUTLET Straits
TIME Marquette advance 19.800 BP)
h. Chippewa low phase
LEVEL Below todav
OUTLET Indian River lowland then Straus
TIME Cary Port Huron interval (13.300-13.000 BPI
c. Intra-Glenwood low phase
LEVEL Calumet
OUTLET Chicago
TIME Two Rivers advance and retreat II 1.800-1 1 2O0BP,
f. Calumet phase
LEVEL Toleston
OUTLET Chicago I
TIME 4.500 BP |
i. Nipissing I phase
Figure 9. Late Wisconsinan and Holocene lake phases in the Lake Michigan basin. Radiocarbon ages are
estimates, a) Early Glenwood I phase b) Glenwood I phase c) Intra-Glenwood low phase d) Glenwood II phase
e) Two Creeks low phase 0 Calumet phase g) Kirkfield phase h) Chippewa low phase i) Nipissing I phase
(from Hansel et al., 1985)
LAKE
MICHIGAN
Figure 10. Reconstruction of the vanished sea cliffs and spit connections of the North Shore
district (from Bretz, 1955).
STOP 5. Lunch and additional discussion of Lake Chicago and Lake Michigan
features, parking area in Gillson Park: S 1/2 SE 1/4 SE 1/4 SW 1/4
Sec. 26, and NE 1/4 NW 1/4 Sec. 35, T. 42 N., R. 13 E., 3rd P.M.,
Cook County; Evanston 7.5-minute Quadrangle (42087A6)].
For about the last 3.3 miles you have traversed an area that was a lake bottom
during the Glenwood phases (640 foot level) and then again later during the
Calumet phases (620 foot level) (fig. 8). The very flat Chicago Lake Plain
according to Willman (1971) is about 45 miles long and about 15 miles wide at
a maximum. It covers approximately 450 square miles, 90 percent or more of
which is covered by built-up areas of Chicago and its suburbs. The plain is
nearly uneroded by modern streams which flow almost on its surface in very
shallow channels.
Rretz (1955) and Hansel, et al (1985) note that the Calumet shoreline does not
show obvious cut terraces in the type area, which suggests that the Calumet
Phase at the close of Lake Chicago time was relatively short-lived (11,800 to
11,200 years BP). The surface elevation of Rose Hill Spit (615 to 620 feet
msl) indicates that it was formed when Lake Chicago was at the Calumet level.
The lake-side of the Rose Hill Spit is fairly steep down to about 600 feet in
elevation, the level of the Toleston shoreline. This latter feature earlier
was thought to represent a stage of Lake Chicago. Radiocarbon dates deter-
mined during the past several years show that the Toleston shoreline is
Holocene in age, formed when Lake Nipissing filled the Lake Michigan basin
from about 5000 to 4000 years RP.
The Lake Michigan level was reached about 2500 years BP. Although the
approximate average lake level is 580 feet msl, the level has fluctuated over
the years. This has become reinforced the last few years when lake levels
rose dramatically in response to climatic conditions affecting the upper Great
Lakes watershed. There is some evidence that indicates that perhaps through-
out most of historical time, the lake has been at low levels, and is now
rising to higher, more normal levels. The increase in lake levels has
resulted in much damage to property along the shoreline as well as consider-
able concern to those who live close to it.
Gillson Park covers about 30 acres nearly half of which are man-made. Much of
the area east of the driveway near the Wilmette Coast Guard Station is made
land. Sheet piling and concrete at the shoreline have given some protection
here. However, the high lake levels and storms have done considerable damage
to the shore protection devices here. The concrete pier has been damaged
too. Make good mental notes of the shoreline here and what has been done to
protect it. Later on you will have the opportunity to examine a much
different type of shoreline, a sea cliff several miles to the north.
STOP 6. Discussion of Skokie River and Skokie Lagoons, peat and muck
deposits. [West side of Forest Way: SE 1/4 NW 1/4 SW 1/4 NE 1/4
Sec. 19, T. 42 N., R. 13 E., 3rd P.M., Cook County; Park Ridge 7.5-
minute Quadrangle (42087A7)].
Skokie River occupies the sag between the Bl odgett and Highland Park Moraines.
This is the lowest sag between the Lake Border Moraines and, as a result, it
contained the longest bay of Lake Chicago. The present-day stream traverses
only four miles of groundmoraine with a gradient of about 4.5 feet per mile
before it reaches and flows across the lake plain where the gradient is a
little more than two feet per mile. Earlier maps of this area indicated a
three mile long marsh into which the river flowed at the north end and from
which it drained at the south end. Extensive alterations are apparent on new
maps which show where lagoons and artificial hills have been constructed to
produce a recreational area.
The material underlying and filling this marsh is the Grayslake Peat.
Although it is dominantly peat, it includes organic silts (muck) and contains
some interhedded silts and sands from local slopewash. It generally is less
than 20 feet thick. Peat is produced in three Illinois counties: Cook, Lake,
and Whiteside. It is used primarily as a soil conditioner to increase the
organic content of the soil and increase its ability to retain moisture.
STOP 7. View of Lake Landfill and discussion of landfills. TNear center S
edge: SE 1/4 NW 1/4 NW 1/4 Sec. 23, T. 42 N., R. 12 E., 3rd P.M.,
Cook County; Park Ridge 7.5-minute Ouadrangle (42087A7)].
The large mound just ahead on the north side of Willow Road is the Lake
Landfill which received its operating permit in January, 1970. This operation
is located on former farm land on the lake plain along the west side of West
Fork North Branch Chicago River which drains the narrow sag between the Park
Ridge and Deerfield Moraines.
The first load of refuse arrived on April 1, 1970. This trench-method
landfill rises about 80 feet above Willow Road at present with nearly 110 feet
of refuse in the center of the structure. Refuse is compacted in trenches
daily and covered with clayey glacial till before being compacted further.
There are 80 vertical wells on the mound and currently they are flaring the
methane gas generated from the decomposition of the refuse materials. The
operators plan to connect the wells through a network of 18,000 feet of pipe
to a compressor/generator plant located along the north side of Willow Road.
Two compressors will compress the collected gas so that it can be used as fuel
for the two turbines that will generate electrical power.
The landfill has 187 acres permitted to date, but it appears unlikely that
additional acreage will become available to them. The result is that this
operation has a life expectancy of only 12 to 18 months. This poses some
rather alarming questions. What will the nearby communities do for disposal
of their refuse? Will they be able to extend the life of this operation by
providing additional land? Will they have to find a new site nearby? Will
they be able to find an adequate, environmentally safe site elsewhere? Will
they be able to answer some of these questions before this operation has to
close?
The Geological Survey has been committed for more than 25 years to mapping
complex geologic and resource information data and presenting it in useful
form so that planners at all levels can make wise land-use decisions. With
detailed geologic information at hand, local officials, citizens, and
industries can avoid improper land uses that could cost millions of dollars to
correct or alleviate at a later time.
STOP 8. Discussion of drainage patterns and problems in this part of the
North Shore area. [Parking area: NW 1/4 NW 1/4 NW 1/4 Sec. 31, T.
43 N., P. 13 E., 3rd P.M., Lake County; Highland Park 7.5-minute
Quadrangle (42087R7)].
The frontal slope of the Highland Park Moraine in this area rises 25 to 40
feet above the sag separating it from the Blodgett Moraine to the west. In
several places the crest of the Highland Park Moraine is 50 to 60 feet above
the Skokie Valley to the west and more than 100 feet above Lake Michigan to
the east.
As noted earlier, a sea cliff faces the lake north of Kenilworth. This cliff
has been retreating westward by wave action ever since the early stages of
Lake Chicago more than 16,000 years BP.
The longest and most numerous ravines in the Chicago area are in the North
Shore area. However, because the area is so built up, fenced, and posted
against trespass, it is difficult to see much of the topography here. All of
the ravines occur on the east slope of the Highland Park Moraine, where the
crest is parallel to the lake shore. The ravines are a consequence of the
wave-cut lake bluff. Here are the steepest slopes in the Chicago area,
therefore, the steepest stream gradients are also here for rapid run-off. The
greatest changes by stream erosion will also occur in this area. Streams form
a dendritic or tree-like pattern with their branching tributaries. The steep
slopes, small valley floors, and moderate-sized undissected upland tracts
suggest that the area is in a youthful stage of landscape development. As the
ravines increase in number and lengthen headward, the eastern slope of the
moraine will become much more dissected and remnants of original slopes will
be reduced. On the Highland Park Quadrangle more than 18 ravines empty along
the lake shore, a number of them have several tributaries. Only one of these
ravines is more than a mile long. The crest of the moraine here is 650 to 680
feet msl . Gradients of 100 feet to the mile are common. Remember the low
gradients of the streams west of the Highland Park Moraine? The small volume,
temporary, wet -weather streams debouching on the lake shore have been able to
incise steep-sided ravines 50 to 60 feet deep. This particular ravine is
slightly more than a mile in length and its gradient is approximately 100 feet
per mile.
STOP 9. Discussion of bluff geology and some of the attendant problems for
North Shore communities. [Parking area: SE 1/4 SE 1/4 SE 1/4 Sec.
25, T. 43 N., R. 12 E., 3rd P.M., Lake County; Highland Park 7.5-
minute Quadrangle (42087B7)].
The top 1.5 inches or so of the macadam along the south side of the parking
area appears to have been ripped loose by torrential flood water coursing down
the short, narrow ravines here as a result of the devastatingly heavy rainfall
that swept the Chicago area during August, 1987.
The bluffs to the north and south of the parking area are developed in wave-
cut, over-steepened glacial till. The only place where the till appears to be
well exposed is a short distance south of the public bathhouse, but the
exposure is on private property. The till is exposed just above the rip-rap
armor that has been placed on the toe of the slope to protect it from direct
wave action. Note that the coarsest material is placed at the base of the
bluff and extends lakeward across the narrow beach developed here.
Factors encouraging erosion along the bluff here include: (1) narrow
protective beach which only partially protects the bluff from wave action,
(2) materials that will quickly slump when the slope is oversteepened, (3) the
removal of protective vegetative cover from some areas by earlier erosion, and
(4) the presence of groundwater seeps that keep the material wet and prone to
slump.
References
Bretz, J. H., 1939, Geology of the Chicago Region: Part I--General : Illinois
State Geological Survey Bulletin 65, 118 p.
Bretz, J. H., 1955, Geology of the Chicago Region: Part II--The
Pleistocene: Illinois State Geological Survey Bulletin 65, Part II,
13? p.
Emrich, G. H., and R. E. Bergstrom, 1962, The Des Plaines Oistrubance,
Northeastern Illinois: Geological Society of America Bulletin, v. 73, p.
959-968.
Hansel, A. K. , et al , 1985, Late Wisconsinan and Holocene History of the Lake
Michigan Basin j_n_ Quaternary Evolution of the Great Lakes: Geological
Association of Canada Special Paper 30, p. 39-53.
Horberg, L., 1950, Bedrock Topography of Illinois: Illinois State Geological
Survey Bulletin 73, 111 p.
Leighton, M. M., G. E. Ekblaw, and L. Horberg, 1948, Physiographic Divisions
of Illinois: Illinois State Geological Survey Report of Investigations
129, 19 p.
Lineback, J. A., et al , 1979, Quaternary Deposits of Illinois Map, 1:500,000-
scale, Illinois State Geological Survey.
Piskin, Kemal , and R. E. Bergstrom, 1975, Glacial Drift in Illinois:
Thickness and Character: Illinois State Geological Survey Circular 490,
35 p.
Reinertsen, D. L., A. K. Hansel, and R. D. Norby, 1981, A Guide to the Geology
of the Zion-Lake Bluff Area: Illinois State Geological Survey Field Trip
Guide Leaflet 1978-D, 40 p.
Willman, H. B., 1971, Summary of the Geology of the Chicago Area: Illinois
State Geological Survey Circular 460, 77 p.
Willman, H. B., and J. C. Frye, 1970, Pleistocene Stratigraphy of Illinois:
Illinois State Geological Survey Bulletin 94, 204 p.
Willman, H. B., et al , 1975, Handbook of Illinois Stratigraphy: Illinois
State Geological Survey Bulletin 95, 261 p.
PLEISTOCENE GLACIATIONS IN ILLINOIS
Origin of the Glaciers
During the past million years or so, an interval of time called the Pleistocene Epoch, most of the northern
hemisphere above the 50th parallel has been repeatedly covered by glacial ice. The cooling of the earth's
surface, a prerequisite for glaciation, began at least 2 million years ago. On the basis of evidence found in
subpolar oceans of the world (temperature-dependent fossils and oxygen-isotope ratios), a recent proposal
has been made to recognize the beginning of the Pleistocene at 1 .6 million years ago. Ice sheets formed in
sub-arctic regions many times and spread outward until they covered the northern parts of Europe and North
America. In North America, early studies of the glacial deposits led to the model that four glaciations could
explain the observed distribution of glacial deposits. The deposits of a glaciation were separated from each
other by the evidence of intervals of time during which soils formed on the land surface. In order of occurrence
from the oldest to the youngest, they were given the names Nebraskan, Kansan, lllinoian, and Wisconsinan
Stages of the Pleistocene Epoch. Work in the last 30 years has shown that there were more than four
glaciations but the actual number and correlations at this time are not known. Estimates that are gaining
credibility suggest that there may have been about 14 glaciations in the last one million years. In Illinois,
estimates range from 4 to 8 based on buried soils and glacial deposits. For practical purposes, the previous
four glacial stage model is functional, but we now know that the older stages are complex and probably
contain more than one glaciation. Until we know more, all of the older glacial deposits, including the Nebraskan
and Kansan will be classified as pre-lllinoian. The limits and times of the ice movement in Illinois are illustrated
in the following pages by several figures.
The North American ice sheets developed when the mean annual tem-
perature was perhaps 4° to 7°C (7° to 13°F) cooler than it is now and
winter snows did not completely melt during the summers. Because the
time of cooler conditions lasted tens of thousands of years, thick masses
of snow and ice accumulated to form glaciers. As the ice thickened,
the great weight of the ice and snow caused them to flow outward at
their margins, often for hundreds of miles. As the ice sheets expanded,
the areas in which snow accumulated probably also increased in extent.
Tongues of ice, called lobes, flowed southward from the Canadian cen-
ters near Hudson Bay and converged in the central lowland between
the Appalachian and Rocky Mountains. There the glaciers made their
farthest advances to the south. The sketch below shows several centers
of flow, the general directions of flow from the centers, and the southern
extent of glaciation. Because Illinois lies entirely in the central lowland,
it has been invaded by glaciers from every center.
Effects of Glaciation
Pleistocene glaciers and the waters melting from them changed the landscapes they covered. The
glaciers scraped and smeared the landforms they overrode, leveling and filling many of the minor valleys and
even some of the larger ones. Moving ice carried colossal amounts of rock and earth, for much of what the
glaciers wore off the ground was kneaded into the moving ice and carried along, often for hundreds of miles.
The continual floods released by melting ice entrenched new drainageways, deepened old ones, and
then partly refilled both with sediments as great quantities of rock and earth were carried beyond the glacier
fronts. According to some estimates, the amount of water drawn from the sea and changed into ice during
a glaciation was enough to lower the sea level from 300 to 400 feet below present level. Consequently, the
melting of a continental ice sheet provided a tremendous volume of water that eroded and transported
sediments.
In most of Illinois, then, glacial and meltwater deposits buried the old rock-ribbed, low, hill-and-valley
terrain and created the flatter landforms of our prairies. The mantle of soil material and the buried deposits
of gravel, sand, and clay left by the glaciers over about 90 percent of the state have been of incalculable
value to Illinois residents.
Glacial Deposits
The deposits of earth and rock materials moved by a glacier and deposited in the area once covered
by the glacier are collectively called drift. Drift that is ice-laid is called till. Water-laid drift is called outwash.
Till is deposited when a glacier melts and the rock material it carries is dropped. Because this sediment
is not moved much by water, a till is unsorted, containing particles of different sizes and compositions. It is
also stratified (unlayered). A till may contain materials ranging in size from microscopic clay particles to large
boulders. Most tills in Illinois are pebbly clays with only a few boulders. For descriptive purposes, a mixture
of clay, silt, sand and boulders is called diamicton. This is a term used to describe a deposit that could be
interpreted as till or a mass wasting product.
Tills may be deposited as end moraines, the arc-shaped ridges that pile up along the glacier edges
where the flowing ice is melting as fast as it moves forward. Till also may be deposited as ground moraines,
or till plains, which are gently undulating sheets deposited when the ice front melts back, or retreats. Deposits
of till identify areas once covered by glaciers. Northeastern Illinois has many alternating ridges and plains,
which are the succession of end moraines and till plains deposited by the Wisconsinan glacier.
Sorted and stratified sediment deposited by water melting from the glacier is called outwash. Outwash
is bedded, or layered, because the flow of water that deposited it varied in gradient, volume, velocity, and
direction. As a meltwater stream washes the rock materials along, it sorts them by size — the fine sands, silts,
and clays are carried farther downstream than the coarser gravels and cobbles. Typical Pleistocene outwash
in Illinois is in multilayered beds of clays, silts, sands, and gravels that look much like modern stream deposits
in some places. In general, outwash tends to be coarser and less weathered, and alluvium is most often finer
than medium sand and contains variable amounts of weathered material.
Outwash deposits are found not only in the area covered by the ice field but sometimes far beyond it.
Meltwater streams ran off the top of the glacier, in crevices in the ice, and under the ice. In some places, the
cobble-gravel-sand filling of the bed of a stream that flowed in the ice is preserved as a sinuous ridge called
an esker. Some eskers in Illinois are made up of sandy to silty deposits and contain mass wasted diamicton
material. Cone-shaped mounds of coarse outwash, called kames, were formed where meltwater plunged
through crevasses in the ice or into ponds on the glacier.
The finest outwash sediments, the clays and silts, formed bedded deposits in the ponds and lakes that
filled glacier-dammed stream valleys, the sags of the till plains, and some low, moraine-diked till plains.
Meltwater streams that entered a lake rapidly lost speed and also quickly dropped the sands and gravels
they carried, forming deltas at the edge of the lake. Very fine sand and silts were commonly redistributed on
the lake bottom by wind-generated currents, and the clays, which stayed in suspension longest, slowly settled
out and accumulated with them.
Along the ice front, meltwater ran off in innumerable shifting and short-lived streams that laid down a
broad, flat blanket of outwash that formed an outwash plain. Outwash was also carried away from the glacier
in valleys cut by floods of meltwater. The Mississiippi, Illinois, and Ohio Rivers occupy valleys that were major
channels for meltwaters and were greatly widened and deepened during times of the greatest meltwater
floods. When the floods waned, these valleys were partly filled with outwash far beyond the ice margins.
Such outwash deposits, largely sand and gravel, are known as valley trains. Valley train deposits may be
both extensive and thick. For instance, the long valley train of the Mississippi Valley is locally as much as
200 feet thick.
Loess, Eolian Sand and Soils
One of the most widespread sediments resulting from glaciation was carried not by ice or water but by
wind. Loess is the name given to windblown deposits dominated by silt. Most of the silt was derived from
wind erosion of the valley trains. Wind action also sorted out eolian sand which commonly formed sand
dunes on the valley trains or on the adjacent uplands. In places, sand dunes have migrated up to 10 miles
away from the principle source of sand. Flat areas between dunes are generally underlain by eolian sheet
sand that is commonly reworked by water action. On uplands along the major valley trains, loess and eolian
sand are commonly interbedded. With increasing distance from the valleys, the eolian sand pinches out, often
within one mile.
Eolian deposition occurred when certain climatic conditions were met, probably in a seasonal pattern.
Deposition could have occurred in the fall, winter or spring season when low precipitation rates and low
temperatures caused meltwater floods to abate, exposing the surfaces of the valley trains and permitting
them to dry out. During Pleistocene time, as now, west winds prevailed, and the loess deposits are thickest
on the east sides of the source valleys. The loess thins rapidly away from the valleys but extends over almost
all the state.
Each Pleistocene glaciation was followed by an interglacial stage that began when the climate warmed
enough to melt the glaciers and their snowfields. During these warmer intervals, when the climate was similar
to that of today, drift and loess surfaces were exposed to weather and the activities of living things. Con-
sequently, over most of the glaciated terrain, soils developed on the Pleistocene deposits and altered their
composition, color, and texture. Such soils were generally destroyed by later glacial advances, but some
were buried. Those that survive serve as "key beds," or stratigraphic markers, and are evidence of the passage
of a long interval of time.
Glaciation in a Small Illinois Region
The following diagrams show how a continental ice sheet might have looked at various stages as it
moved across a small region in Illinois. They illustrate how it could change the old terrain and create a
landscape like the one we live on. To visualize how these glaciers looked, geologists study the landforms
and materials left in the glaciated regions and also the present-day mountain glaciers and polar ice caps.
The block of land in the diagrams is several miles wide and about 10 miles long. The vertical scale is
exaggerated — layers of material are drawn thicker and landforms higher than they ought to be so that they
can be easily seen.
The Region Before Glaciation — Like most of Illinois, the region illustrated is underlain by almost flat-lying beds of
£), and shale ( =EI^)- Millions of years of erosion
1.
sedimentary rocks — layers of sandstone (■■•■••.••:■). limestone (.
have planed down the bedrock (BR), creating a terrain of low uplands and shallow valleys. A residual soil weathered
from local rock debris covers the area but is too thin to be shown in the drawing. The streams illustrated here flow
westward and the one on the right flows into the other at a point beyond the diagram.
3=C
-.? ....'.■.'.....'.■..'.. .*. r^r
2. The Glacier Advances Southward — As the Glacier (G) spreads out from its ice snowfield accumulation center, it
scours (SC) the soil and rock surface and quarries (Q) — pushes and plucks up — chunks of bedrock. The materials are
mixed into the ice and make up the glacier's "load." Where roughnesses in the terrain slow or stop flow (F), the ice
"current" slides up over the blocked ice on innumerable shear planes (S). Shearing mixes the load very thoroughly. As
the glacier spreads, long cracks called "crevasses" (C) open parallel to the direction of ice flow. The glacier melts as it
flows forward, and its meltwater erodes the terrain in front of the ice, deepening (D) some old valleys before ice covers
them. Meltwater washes away some of the load freed by melting and deposits it on the outwash plain (OP). The advancing
glacier overrides its outwash and in places scours much of it up again. The glacier may be 5000 or so feet thick, and
tapers to the margin, which was probably in the range of several hundred feet above the old terrain. The ice front advances
perhaps as much as a third of a mile per year.
3. The Glacier Deposits an End Moraine — After the glacier advances across the area, the climate warms and the
ice begins to melt as fast as it advances. The ice front (IF) is now stationary, or fluctuating in a narrow area, and the
glacier is depositing an end moraine.
As the top of the glacier melts, some of the sediment that is mixed in the ice accumulates on top of the glacier.
Some is carried by meltwater onto the sloping ice front (IF) and out onto the plain beyond. Some of the debris slips down
the ice front in a mudflow (FL). Meltwater runs through the ice in a crevasse (C). A supraglacial stream (SS) drains the
top of the ice, forming an outwash fan (OF). Moving ice has overridden an immobile part of the front on a shear plane
(S). All but the top of a block of ice (B) is buried by outwash (O).
Sediment from the melted ice of the previous advance (figure 2) remains as a till layer (T), part of which forms the
till plain (TP). A shallow, marshy lake (L) fills a low place in the plain. Although largely filled with drift, the valley (V)
remains a low spot in the terrain. As soon as the ice cover melts, meltwater drains down the valley, cutting it deeper.
Later, outwash partly refills the valley: the outwash deposit is called a valley train (VT). Wind blows dust (DT) off the dry
floodplain. The dust will form a loess deposit when it settles. Sand dunes (D) form on the south and east sides of streams.
T..; ■■'■■.■.',.■...'■■■'.'..;■'■■. ■■,.',. :.7r'..,', ■'•■'■.•'.■' ■■'■-.'.- \-^ ■' ■!^P^y^Z7^P^ .\\.^C^^. ^ ^!...\^ ^.\\^.^ .\-J
4. The Region after Giaciation — As the climate warms further, the whole ice sheet melts, and glaciation ends. The
end moraine (EM) is a low, broad ridge between the outwash plain (OP) and till plains (TP). Run-off from rains cuts
stream valleys into its slopes. A stream goes through the end moraine along the channel cut by the meltwater that ran
out of the crevasse in the glacier.
Slopewash and vegetation are filling the shallow lake. The collapse of outwash into the cavity left by the ice block's
melting has made a kettle (K). The outwash that filled a tunnel draining under the glacier is preserved in an esker (E).
The hill of outwash left where meltwater dumped sand and gravel into a crevasse or other depression in the glacier or
at its edge is a kame (KM). A few feet of loess covers the entire area but cannot be shown at this scale.
TIME TABLE OF PLEISTOCENE GLACIATION
STAGE
SUBSTAGE
NATURE OF DEPOSITS
SPECIAL FEATURES
>
<
z
cc
LU
I-
<
o
HOLOCENE
(interglacial)
WISCONSINAN w
(glacial)
■g
E
SANGAMONIAN
(interglacial)
ILLINOIAN
(glacial)
YARMOUTHIAN
(interglacial)
KANSAN*
(glacial)
AFTONIAN*
(interglacial)
NEBRASKAN*
(glacial)
Years
Before Present
10,000 -
Valderan
- 1 1 ,000 -
Twocreekan
- 12,500 -
Woodfordian
- 25,000
Farmdalian
■ 28,000 -
Altonian
75,000
125,000
Jubileean
Monican
Liman
300,000?
500,000?
700,000?
900,000?
1 ,600,000 or more
Soil, youthful profile
of weathering, lake
and river deposits,
dunes, peat
Outwash, lake deposits
Peat and alluvium
Drift, loess, dunes,
lake deposits
Soil, silt, and peat
Drift, loess
Soil, mature profile
of weathering
Drift, loess, outwash
Drift, loess, outwash
Drift, loess, outwash
Soil, mature profile
of weathering
Drift, loess
Soil, mature profile
of weathering
Drift (little known)
Outwash along
Mississippi Valley
Ice withdrawal, erosion
Glaciation; building of
many moraines as far
south as Shelbyville;
extensive valley trains,
outwash plains, and lakes
Ice withdrawal, weathering,
and erosion
Glaciation in Great Lakes
area, valley trains
along major rivers
Important stratigraphic marker
Glaciers from northeast
at maximum reached
Mississippi River and
nearly to southern tip
of Illinois
Important stratigraphic marker
Glaciers from northeast
and northwest covered
much of state
(hypothetical)
Glaciers from northwest
invaded western Illinois
*Old oversimplified concepts, now known to represent a series of glacial cycles.
(Illinois State Geological Survey, 197:
SEQUENCE OF GLACIATIONS AND INTERGLACIAL
DRAINAGE IN ILLINOIS
PRE-PLEISTOCENE
major drainage
PRE-ILLINOIAN
inferred glacial limits
YARMOUTHIAN
major drainage
LIMAN
glacial advance
MONICAN
glacial advance
JUBILEEAN
glacial advance
SANGAMONIAN
major drainage
ALTON IAN
glacial advance
WOODFORDIAN
glacial advance
WOODFORDIAN
Valparaiso ice and
Kankakee Flood
VALDERAN
drainage
(Modified from Willlman and Frye, "Pleistocene Stratigraphy of Illinois," ISGS Bull. 94, fig. 5, 1970.)
Illinois Statt Giologicai. Survly
ILLINOIS STATE GEOLOGICAL SURVEY
John 5 Frye, Chief Urbono, Illinois 61801
77T??^?'is?'rriT>EiSi^ Y\ LAKE
f-» -«!-.. »■*■«•« •'**— «■-*— -^— ' ' SNSVJ
\ CARROLL * * * * J 'OGLE ■ ■ ■ V5X"">S
'":::: j:::::^^P-
GLACIAL MAP OF ILLINOIS Mi
■I:
ALB-:-:j:y ANfv i * : coo*
H.B. WILLMAN and JOHN C. FRYE f:$
r
1970
F/'/HOCK ISLAND
'.'lirorrB . .1
Modified from mops by Leverefl (1899). YV:\
EKblow (1959), Leigh ton and Brophy (1961), Vp-'yf
Willman et ol.(l967), ond others
!::::!' :K.N?f \ : :^?> STARK
IJ/.i
^y(Ar*;At<£e
ff
l/fcr LIVlSpStON
f
EXPLANATION
HOLOCENE AND WISCONSINAN
Alluvium, sand dunes,
'•■■'•'•'•'•"'■'•'< ond gravel terraces
WISCONSINAN
Lake deposits
WOOOFOROIAN
Moraine
Front of moroinic system
Groundmoraine
ALTONIAN
Till plain
ILLINOIAN
Moraine and ridged drift
Groundmoraine
KANSAN
Till plain
DRIFTLESS
Modified from Bull- 94. -pi. 2
QUATERNARY DEPOSITS OF ILLINOIS
Jerry A. Lineback
1981
Modified from Quaternary Deposits
of Illinois (1979) by Jerry A. Lineback
AGE
rvCwXwy5
"*:oH«:t~ "T.-'.-m.
,£vIM- ''1ST'- ' 'r
I m
m^
» . ■ * •••!£• V/TtjLA
?V*Iv •VfVZP.VlV
'••>
^tn
:
•■•J«M&
•NSnJ
. 1
.1
J^>^^^
iyjy!
^SS1
;>"-
~-l
•V
&:<&<
UNIT
::::::>::*
')"i:'/
^Qs&tii%£j5&&iQ$^^^^
»**^7 s ^w^r •,> jfl
Holocene U_^-_- Cahokia Alluvium,
and > '
Wisconsinan
Parkland Sand, and
Henry Formation
combined; alluvium,
windblown sand, and
sand and gravel outwash.
Wisconsinan K*T*!*j Peoria Loess and Roxana Silt combined;
windblown silt more /[
than 6 meters (20 ft) thick
Equality Formation; silt, clay, and
sand in glacial and slack-water lakes
Moraine
Ground
moraine
Wedron and Trafalgar
Formations combined;
glacial till with some
sand, gravel, and silt.
Wisconsinan
and
lllinoian
WM
Winnebago and Glasford Formations
combined; glacial till with some sand,
gravel, and silt; age assignments of some
units is uncertain.
lllinoian kx'jiyivl Glasford Formation; glacial till with some sand,
'•■•■•'■•'.■I-J gravel, and silt.
I Teneriffe Silt, Pearl Formation, and Hagarstown Member
I of the Glasford Formation combined; lake silt and clay,
outwash sand, gravel, and silt.
Pre-lllinoian k/*v*vl Wolf Creek Formation; glacial till with gravel, sand,
CA3 and silt.
Bedrock.
ISGS 1981
rpyTT^T-^
20 000
2$ 000 FEET
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