511
THE GLACIAL BOUNDARY
IN
H. B.
SOUTHERN
Willman and John
C.
ILLINOIS
Frye
,
-III
inoian glacial border
Probable ice-front lakes
***• Mississippi River bluffs
10
km
3
Illinois Institute
of Natural Resources
ILLINOIS STATE
GEOLOGICAL SURVEY DIVISION, URBANA, ILLINOIS
Jack A. Simon, Chief
CIRCULAR
511
1980
Willman, Harold B.
The
glacial
and John
boundary in southern Illinois / by H. B. Willman
-Urbana
Illinois State Geological Survey
C. Frye.
:
Division, 1980.
23
p.
:
figs.
;
28cm.
--
(Circular- Illinois. Geological Survey
511)
1
.
Geology-Illinois.
I.
Frye, John C.
II.
Title.
;
THE GLACIAL BOUNDARY
IN
H. B.
SOUTHERN
Willman and John
Illinois Institute
C.
ILLINOIS
Frye
of Natural Resources
ILLINOIS STATE
GEOLOGICAL SURVEY DIVISION, URBANA, ILLINOIS
Jack A. Simon, Chief
CIRCULAR
511
1980
Digitized by the Internet Archive
in
2012 with funding from
University of
Illinois
Urbana-Champaign
http://archive.org/details/glacialboundaryi511will
CONTENTS
Abstract
1
Introduction
1
Previous mapping
Present
1
mapping
2
in mapping
The Fountain Bluff Diversion Channel
Problems
4
5
Stratigraphic relations
7
Physiographic relations
7
Characteristics of the drift
8
Thickness
Lithology
8
8
8
Mineral composition
8
Topography
Weathering
Age and
origin
Characteristics of the loess
Distribution and thickness
Stratigraphy
9
9
10
10
10
10
Glacial lakes
Glacial Lake Sugar
Glacial Lake
Wagon
11
13
Glacial Lake Little Saline
15
Lake Panther Den
15
Glacial
Glacial Lake Antioch
17
Lake Indian
Glacial Lake Drury
17
Glacial
Glacial
Lake Clay Lick
19
19
APPENDIXES
1.
Clay-mineral and carbonate compositions of samples
2.
Geologic sections
REFERENCES
20
20
23
FIGURES
border and ice-front lakes
1.
Illinoian glacial
2.
Generalized southern boundary of Illinoian glaciation
in Illinois
and previous mapping
3.
Diversion of the Mississippi River at Fountain Bluff
4.
Glacial
5.
6.
7.
boundary
Glacial boundary
Glacial boundary
Glacial boundary
and ice-front lakes— eastern area
and ice-front lakes—east-central area
and ice-front lakes— west-central area
and ice-front lakes— western area
2
3
6
12
14
16
18
THE GLACIAL BOUNDARY
SOUTHERN
IN
H. B.
Willman and John
C.
ILLINOIS
Frye
ABSTRACT
Ground-water resources, the productivity of
soils,
and many engineering problems differ between the
glaci-
drift.
Continental
maximum
glaciation
Hemisphere reached
Northern
the
in
its
southern extent during the lllinoian glaciation only a few
miles north of the crest of the
Shawnee
Hills in
southern
ated and nonglaciated regions.
Illinois.
The southernmost known exposure of glacial till is near the northo
o
ern boundary line of Johnson County (37 34' 50" N., 88 56
W.). To the south of that exposure, isolated boulders in Illinois and
the present report, previous mapping of the border
In
of the drift has been modified, and the characteristics and
'
Missouri
may
lllinoian
glacier
The
represent an as yet unproven older glaciation.
appears to
have
lost
momentum and
stagnated
it mounted the northern slope of the Shawnee
The thinness of the drift and the absence of depositional
forms suggest rapid advance, perhaps a surge, which could account
almost as soon as
stratigraphic relations of the drift near the border, of lakes
formed
in
valleys
dammed by
the glacier, and of the loess
that largely mantles the border of the drift are described
(fig. 1).
Hills.
for the glacier's extending so far south. This report includes revision
boundary of the lllinoian glaciation for several areas and
maps showing many short-lived ice-front lakes that ponded in the
northward-sloping valleys. The presence of an unusually high
of the
content of expandable clay minerals
the Mississippi Valley
is
in
the outermost drift near
attributed to the deposition of loess on the
drift during ablation. The presence of
narrow channel entrenched in bedrock
along the western side of Fountain Bluff is attributed to diversion
glacier
and
mixing with the
a
the Mississippi River
by
a
in
a
lobe of the
small
lllinoian
glacier;
however, the diversion
was abandoned and reoccupied
twice before the Holocene valley-fill reached its present
channel
probably
reestablished the river in
its
at
least
level
and
present channel, probably in the
last
PREVIOUS MAPPING
The approximate position of the southern margin of the
area covered by drift in Illinois was probably known to the
pioneer geologists by 1850 or a little earlier. A. H. Worthen
(1866,
p.
27) described the distribution of the drift
southern boundary
Illinois: "Its
the mountain chain, already mentioned, which crosses the
southern portion of the State from Grand Tower on the
on the Ohio." Worthen
Shawneetown,
to
Mississippi,
thought that the drift was
one to two thousand years.
in
State appears to be
in this
a water-laid deposit
and that the
margin of the drift was determined by the "mountain
chain"
rising
the
INTRODUCTION
"mountain chain"
glacial
boundary across southern
Illinois
southernmost extent of the continental
Northern
ice
marks the
sheet
in
the
Hemisphere during the Pleistocene glaciation.
This advance of the glacier occurred during the lllinoian
Stage of glaciation. At
its
maximum
extent, the front of
two to three miles north of the crest
of the Shawnee Hills. Had it reached the crest, the glacier
would have had a downgrade slope into the Mississippi
Embaymerrt Region.
The boundary of the area covered by the glacier is
the glacier was only
significant because useful deposits of sand, gravel,
drift.
found
and clay
Wright
F.
called
the boundary
in
southern
mile of Wright's boundary
"Shawnee
Hills"
the eastern part of
glacial
at the
(fig.
2). All
maps pub-
boundary within about
a
an interval of approximately
where the boundary must be
is
Lake Saline and the Wabash Valley bottomland, and
western edge of
covered by thick
the
present
topography.
where the margin of the drift
The position where the ice front
Valley bottomland, which was lower
Illinois,
loess.
than
ILLINOIS
in
Illinois,
entered the Mississippi
SOUTHERN
boundary
projected through the broad, flat areas formerly covered by
the bedrock formations are
IN
glacial
35 miles (56 km) from central Jackson County to eastern
in mapping are greater in
association with, the glacial
THE GLACIAL BOUNDARY
the
Williamson County. Differences
in
favored by the absence of a cover of glacial
Illinois
lished since then have placed the
in
in,
traced
(1890)
or
commonly
general
through several eastern and midwestern states and mapped
Mining and quarrying
are frequently
now
is
his
adequate, although
still
is
(fig. 1).
G.
The
above the waters. Nevertheless,
of the boundary
description
floodplain,
is
not
apparent
in
the
Frank
Leverett
modified
(1899)
Wright's
mapping
across southern Illinois by extending the margin southward
about 10 miles (16 km) in western Saline County and near
the Wabash River and by retracting it about 5 miles along
the Mississippi River bluffs in Jackson County.
On the state geologic map of 1917 (De Wolf, 1917),
the glacial boundary was again modified; in this revision,
moved northward from its
southernmost extent in northern Johnson County. The
first detailed mapping of a segment of the boundary was by
Lamar (1925), who showed the intricacy of the
J. E.
the boundary was incorrectly
ern
part
Counties.
of the glacial boundary
On
the basis of
a
in Saline and Gallatin
few cobbles of igneous rocks
south of Harrisburg, he projected the
southward to the base of Cave
Hill
boundary
glacial
and Wildcat
Hills
south
mapping was shown on the state
geologic map of 1945 compiled by J. Marvin Weller.
In 1961 G. A. Desborough mapped the boundary of
of
Equality. Ekblaw's
the drift
in
the
Pomona 7.5-minute Quadrangle
western end of the area and showed
its
near the
position in greater
than had been mapped previously.
detail
On
miles (24 km). In that area, the ice front appears to have
the 1967 state geologic map, we followed the
mapping of Lamar and Desborough for the western part of
the boundary but again modified the mapping of the
developed tongues extending up the narrow valleys eroded
eastern part, returning the
boundary crossing the Carbondale Quadrangle for about 15
in
the northern slope of the Shawnee
Hills.
Lamar
also
position, largely because
boundary to
we
a
more northerly
did not find the evidence cited
high enough for overflow through the Water Valley and
by Ekblaw and because the hills south of Eldorado showed
no indications of glaciation. This mapping was shown in
Cobden Cols
more
indicated the probable existence of ice-front lakes at levels
(locations
shown
in figs.
6 and
7).
detail
by Frye and others (1972).
1930s Paul MacClintock reexamined the
entire boundary in southern Illinois and described numerthe late
In
ous exposures of drift and the position of the boundary. He
PRESENT MAPPING
prepared only a general map, and his preliminary report was
not published (MacClintock, 1940). His boundary did not
The
change the previous mapping significantly.
Saline
After extensive mapping of materials for building roads
in
southern
Figure
1
.
Illinois,
George
E.
Ekblaw remapped the
Illinoian glacial border, ice-front lakes,
east-
and areas shown
glacial
boundary
in
the eastern part of
Illinois,
in
and Gallatin Counties, was not restudied for the
present report.
The boundary along the western edge of
that area has been modified slightly, and minor changes in
in figures
4 through
7.
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GEOLOGICAL SURVEY CIRCULAR
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ISGS 1979
Figure 2. Generalized southern boundary of lllinoian glaciation in
line) includes
Illinois
and previous mapping. The boundary described
in this
report (solid
others where they are too close to differentiate.
the boundary in the central and western parts of the area
be required to demonstrate the presence or absence of
have been made, largely on the basis of a few new expo-
glacial drift.
sures of drift, the identification of minerals in the alluvium
of streams crossing or bordering the boundary, and exposures near the
boundary with evidence that that
locality
had not been glaciated. More detailed mapping of the
boundary
is
permitted by the greater topographic detail
New
roadcuts,
especially
new
those along
Interstate
57,
Highway 51 south of Carbondale gave new control on the boundary. The new cuts
along Interstate 24, 2 miles (3 km) north of Goreville
(geol. sees. 6, 7; app. 2), show the till, and about a quarter
Interstate 24, and
U.S.
shown on new 7.5-minute quadrangle topographic maps
mile farther south they expose bedrock that probably could
that cover the entire area.
not have been glaciated by the lllinoian
Exposures along most of the roads and
near the
mapping
rangle
boundary were examined for
will
maps
many
this
few ravines
study.
The
be improved when the new 7.5-minute quadare geologically
valleys, ravines,
in
in a
mapped
in detail,
and
all
the
and shorelines are carefully traversed, but
areas extensive drilling to the bedrock surface will
THE GLACIAL BOUNDARY
IN
SOUTHERN
ILLINOIS
sure of
till
glacier.
farther east and a quarter mile farther south
accepted
as
the southernmost occurrence
Hemisphere of
glacial
till
ice sheet.
This occurrence,
T. 11
R. 2 E.,
S.,
An
expo-
noted by MacClintock (1940) about 2 miles
deposited
in
the
in
is
presently
the Northern
by the continental
SW%NE%NE%
Sec. 12,
Johnson County (37° 34' 50" and 88°
shown
56' 0") (location
in fig. 5)
is
now
by
largely buried
the waters of Lake of Egypt, but four very small ridges
extending just above water
level,
shown on the
Quadrangle map, probably consist of the
Sand washed from the
silty
readily
is
drift described
alluvium along valleys that
identified
by the presence of
grains of hornblende, garnet, zircon, black opaques, feldspars,
and an abundance of chert. These and
other minerals are abundant
alluvium
much
of
common. Chert
sandstones.
rare or absent.
is
of
a variety
The sand from the
consists largely
till
secondarily enlarged like the sand
it
Pennsylvanian
the
till.
the valleys that do not have
in
of quartz,
the
in
quartz
Pink
grains
in
are
These mineral grains can
be identified readily, using only a binocular microscope,
in
the washed concentrate without the necessity of making
or
grain-size
heavy-mineral
proved particularly helpful
A
the Mississippi Valley.
a
ravine
W.
(cen.
quarter
a
in
This
separations.
northeast of
was found
till
3 for location). The sand from the alluvium
fig.
abundance of the
valley contains an
was found
till
in
Fairview Church
contains
less
than
in
Church
Fairview
1S-2W, Jackson Co., Gorham Quad; see
line 31,
in
that
No
glacial minerals.
the ravine 1/8 mile (0.2 km) southwest of
NW
(SW
a variety
SE
parts of the area.
by
and colluvial deposits and by man-made
river
25
but the steepest valley slopes.
all
m)
feet (7.6
km) and
River bluffs for about 5 miles (8
Mississippi
thinner
slightly
thickness exceeds
Its
the area extending eastward from the
in
River bluffs.
m)
thins to about 5 feet (1.5
It
in
Saline and
eastern Williamson Counties. As a result, a large proportion
of the cuts along the roads do not completely penetrate
the loess.
In Saline
many
Shawnee
Hills to
dammed by
Ohio
and
and Gallatin Counties, the Saline River and
had
tributaries
low
a
large
level that
they were effectively
in the Wabash
from the Wisconsinan
outwash
by
Valleys
square miles of the Saline drainage area were
covered by slackwater, called Lake Saline,
of
in
and clay, commonly 10 to 20 feet
silt
much
Glacial
till
is
feet,
which deposits
(3 to
6 m) thick,
accumulated (Fryeetal., 1972).
well exposed around the northern and western
boundaries of Lake Saline, and the absence of drift between
and deeply weathered bedrock on several
the
underlies the loess and the slumped loess in
lands" in the lake plain favors mapping the ice margin
heading near the Fairview School, a drainage area of
about 20 acres
(8 ha).
A
sample from a valley 0.7 mile
(1.1
km) farther southwest, in the headwaters of the Little
Grand Canyon (NE SW NW 1, 10S-3W), contained no
glacial minerals. The same relations were useful elsewhere.
The evidence that suggests a locality was not glaciated,
thus establishing a southern limit for glaciation beyond the
last drift
Silt,
exposures,
is
Silt
glaciation,
is
and
it
present.
is
found only beyond the area of
generally overlies a deep soil
by the younger Wisconsinan
suggests that the locality
lation
is
lllinoian
less
soil
was not
on the bed-
but that
It
boundary
in
gruous
that the
it
is
incon-
Wabash and
divide between the
Mississippi Valleys.
is
re-
Thinness of
late
lllinoian,
till
m)
(3
in
nearly
indicating
that the
advancing glacier
soil.
thick.
absence
this
in
In
the outer
It
is
1
to 3 miles
has a patchy distribution, as
by the
mapping of the boundary of the glacial drift
handicapped in some areas by (1) the cover of loess or
lake sediments, (2) the thinness of the drift, (3) the exten-
is
shown by
glacier.
its
North of
almost continuously present except where
topography of the
raphy
in
lllinoian
drift
only a few
till
plain.
has a recognizable glacial topog-
localities.
In
most of the area near
the margin, the bedrock topography
sharply dissected, and
much
the steep slopes,
could
where remnants of
it
are
The thinness of the
stagnation.
as
km) of
eroded along valleys, and has the normal relatively
have slumped
now
a
tered
The marginal
deposited on
if
into
the valleys,
buried beneath alluvium.
drift appears to
ice
very deeply and
is
of the drift,
related to the thinness of the ice and to
precise
to 5
thinned area, the drift averages about 35 feet (11 m)
The marginal
mapping
(1
seldom more than 10 feet
areas certainly covered
in thickness,
Sanga-
overlying bedrock, the bedrock
drift.
the glaciated area, the drift
flat
relatively
is
the Wabash
across
Indiana, but
in
advanced farthest south along the
ice
higher bedrock
slightly
soil
is
More
in
the Lake Saline areas remains
northeastward
projects
Valley to the glacial boundary
have been eroded and a strong
exposures of lllinoian
in
uncertain.
locally
all
Problems
position of the
pre-
till
monian, and early Wisconsinan time. Nevertheless,
generally eroded the
"is-
the northern part of the lake plain. Nevertheless, the exact
and the
developed on the bedrock during
fresh,
it
loesses also strongly
glaciated,
convincing because thin
could
The
lllinoian
rock surface. Deep weathering of the bedrock where
overlain
loess
most convincing where the Loveland
the basal part of the loess succession,
Loveland
its
north of the
areas
the aggrading valley trains built
Many
glaciers.
such
eroded
minerals. This indicates that at least a small
lies
is
the immediate vicinity of the Wabash
in
more than 50
amount of till
some of the gul-
areas
lakes.
Loess mantles almost the entire area, both the uplands
and
locally
of glacial minerals, proportionally
some
deposits, mostly loess and lake deposits, but in
36, 9S-3W), but the alluvium
the previous ravine and mixed with the bedrock
in
some
Sediment cover. The major obstacle to mapping the glacial
boundary accurately is burial of the boundary by younger
technique
the areas of thick loess near
small exposure of
mile
of the drift both before and after deposition of
the loess, and (4) inaccessibility of
Goreville
by MacClintock.
cut glacial drift
sive erosion
may
be
its
at least in part
dissolution by
have been unusually thin
consequence of increased resistance to flow encoun-
by the
glacier as
ILLINOIS STATE
it
advanced up the slope of the
GEOLOGICAL SURVEY CIRCULAR
511
Shawnee
more
retarding the advance of the
Hills,
heavily
laden lower part of the glacier. The general absence of a
moraine along the boundary suggests that the
terminal
glacier stagnated almost immediately
mum
in
common
extent, a
on reaching
maxi-
its
characteristic of lllinoian glaciers
through
this
Ferry.
seems
It
developed
down
The
A
principal cause for the thinness of
the drift in the marginal area
is
erosion, accelerated
Throughout
relatively high relief in that area.
and Sangamonian time and, to
by the
late lllinoian
during and
a lesser extent,
following deposition of the Wisconsinan loesses, the drift
was subject to erosion, which completely removed the
in
some
the
fine constituents
can account for those upland
till
of
level
Only erosion of the
areas.
possible
where
lakes,
localities,
unlikely because the
boundary
loess
by the
Bluff
deemed
boundary were not
lllinoian ice sheet.
Much of
in
the Shawnee National
is
in
which some roads have
Forest, in
valleys.
Therefore,
not maintain
occupy
many
valleys.
likely that the Mississippi River did
position
in
the diversion channel
its
channel to the depth of the
The mapping
River bottomland offers
a special
problem because
intervals
the Wisconsinan valley train aggraded the Missis-
higher than the present floodplain, the river could have
abandoned
the
Evidence
channels.
lllinoian
elsewhere
of what must have been
The
locality
where the
near Fairview Church
of
a
complex
is
ice
direct evidence
history.
the
50
least
present
The
defined by exposures
lllinoian glacier appears
feet (15
m) below the present floodplain
valley-fill
present channel, and
Mississippi
itself
in
its
Bake
it
is
the
have reoccupied
normally only by the Big
essentially a
floodplain.
valley east of
perhaps
in
the
last
in
Muddy
narrow valley
a
It
is
River,
(fig.
3)
meandering stream on the surface of
The floodplain
close that the Mississippi River could have
broad
at
subject to flooding by the
which enters the major valley from
the
Bluff, the
the valley was aggraded to
could
except where prevented by man-made levees.
river,
now occupied
which were then on the eastern side of Fountain Bluff
(fig. 3), and to have diverted the Mississippi River onto the
entrenched
When
river
began, and at
abandoned the channel
The broad floodplain east of Fountain Bluff is
same level as the floodplain of the river
is
it
after
essentially the
and
present narrow valley west of Fountain
the
level,
to have crossed the Mississippi Valley to the western bluffs,
margin of the upland, where
utilizing
that
diversion channel, again utilizing both channels.
its
front reached the bluff
fairly closely
as previously described.
till,
all
channel,
indicates
building the Wisconsinan valley train, the river entrenched
of widening, deepening, and aggrading of the valley since
lllinoian time appear to have destroyed
long
abandoned the new channel and returned
west of Fountain Bluff.
the Mississippi
apparently
since lllinoian time.
that time the river could again have
The Fountain Bluff Diversion Channel
and
floodplain
Valley to a level at least 20 to 30 feet (6 to 9 m)
sippi
itself at
in
essentially
on the absence of
also
before deposition of the Holocene
of the glacial boundary
based on extent of
previous broad valley east of Fountain Bluff.
its
of
that
the
river to cut
glacier, the river
encroachment
lakes
is
old channel. Consequently, following the melting of the
both
from the
fill
seems
it
its
enough for the
reoccupied
man-made
of the valley floor
deposits of Wisconsinan
valleys,
below
indicate an extensive
of old
part also results
these
In
extend
terraces
Abandonment
in
level
from the upland
Silt
modern floodplain and
the
to
been abandoned and large areas are essentially inaccessible.
roads
on bedrock, but
flowing
the broad expanse east of Fountain Bluff was probably
the loess of the Loveland
to
the area along the boundary
present course west of
its
considerably lower. This conclusion
When
Inaccessibility.
in
essentially
is
terraces of lllinoian age along the lower sections of tribu-
above the
is
River
Mississippi
tary
stratigraphy and residual soils
indicate that the areas south of the
glaciated
mapped
as
in
drift
erosion entirely removed the drift for a consider-
able distance south of the
have
shown
farther than
the valley even
during the lllinoian glaciation the
and boulders of foreign rocks have been found. The possibility that
would have
could
it
from
pebbles, cobbles,
isolated
and
Valley,
Mississippi
figure 3.
Fountain
drift.
likely that a lobe of the glacier
the
in
projected
other areas.
Erosion of the
channel to the eastern bluffs at Rattlesnake
levels
are
so
abandoned the
Fountain Bluff only very recently,
one or two thousand
years.
The
river
Oven, and the Backbone (Leighton and Brophy, 1961);
however, neither till nor erratics have been found on
seems to be prevented from returning to the valley east of
Fountain Bluff, nor elsewhere on the western bluffs of the
that
valley, to prove this interpretation.
of the floodplain and possibly
The
Walker
for
nel
if
isolation also of the
Hill,
Bake Oven, the Backbone, and
between Fountain
lllinoian
a
Bluff
and Walker
Hill,
which
in
time probably was the lower part of Brazeau
prominent tributary that follows the fracture zone
of the Ste. Genevieve Fault
THE GLACIAL BOUNDARY
in
IN
Missouri.
The
SOUTHERN
fault extends
ILLINOIS
is
a
low sandy area north of Fountain Bluff
scarcely 5 feet (1.5
m) higher than the remainder
a
is
remnant of
a slightly
older floodplain surface or a broad natural levee.
south of Fountain Bluff, could be accounted
the ice extended far enough south to block the chan-
Creek,
Fountain Bluff by
In its position
some distance
is
directed
along the western side of the valley for
to the north, the
against
the western
main current of the river
side of Fountain Bluff,
which was probably the major reason, before modern
were
built, that
the river maintained
the narrow diversion channel during
its
many
levees
position through
flood stages.
——
Q
">
Bluff line
i
2 mi
Figure 3. Diversion of the Mississippi River at Fountain Bluff.
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
not impossible that the original diversion resulted
is
It
from
a high level of the river
during Wisconsinan glaciation
would have enabled the
that
low
river to flood across a
southward-sloping surface on which a low, broad, north-
bedrock
south
ridge
diverts
Wabash Valley and westward
This surface declines to as low as
west of Fountain Bluff, or perhaps even later from be-
sea level before
heading of the tributary and capture of the river by the
However, the evidence that the
stream.
small
glacier
the
entered
Fountain Bluff
at
Valley
Mississippi
lllinoian
directly
of
east
present favors glacial diversion as the
now
cause for the narrow channel west of Fountain Bluff
occupied by the Mississippi River.
300
feet (91
top of
at the
capped by the
a
m) above
distance of only 5 to 10 miles
16 km), to the crest of the Shawnee
(8 to
is
rises, in a
the
to
the Mississippi Valley.
to
divide into a southward-flowing tributary of Brazeau Creek
it
eastward
drainage
Hills.
The
crest
prominent southward-facing escarpment
resistant sandstones
forming the lower part
of the Pennsylvanian strata. Along the crest, a few
hills
are
over 1,000 feet (305 m) in elevation, but generally the
divide
800 to 900
is
feet (244 to
274 m) with low
cols
around 700 feet (213 m).
For about 30 miles (48 km) east of the Mississippi
STRATIGRAPHIC RELATIONS
mounted the northern slope of
Shawnee Hills, rising from a level of 300 to 400 feet (91
to 122 m) at the foot of the hills to as high as 680 feet
(207 m). At its highest advance, the ice front was only
about 2 miles (3 km) from and 150 feet (46 m) lower than
Valley, the lllinoian glacier
boundary of the
The southern
drift
glacial
Illinois
in
everywhere overlies bedrock formations of Pennsylvanian
age that dip northerly into the Illinois Basin. In the western
half
of the area, the boundary overlies and
commonly
Formations, which are mostly sandstone and
cliff
forming.
northerly
younger
In
more
the eastern half, the boundary turns
the
into
roughly
is
and overlying Abbott
parallel to the strike of the Caseyville
Carbondale,
the divide between the drainage flowing northward to the
Muddy
Big
Valley and southward to the Cache Valley.
At one unusually low point
shown
Col (location
and
basin
the
successively
crosses
Bond
and
Modesto,
the
Formations,
which are more dominantly shaly formations that have
the divide, the Water Valley
the ice front was slightly
less
than 2 miles from the divide and crossed ridges about
75
m) higher than the col.
The streams on the northern
feet (23
less
The top of the bedrock is a major unconformity along which younger Pennsylvanian, Cretaceous,
in
in fig. 6),
slope of the
Shawnee
surface relief.
a
and Tertiary formations that are present
in
nearby areas
are absent.
pronounced
All of the drift near the
border of the glaciated area
is
in
and consists largely of
lenses of lacustrine
gravel.
The
and windblown
till
silt
and
local
beds or
and outwash sand
overlain
is
by
loess of Wis-
most
sediments, and
consinan
age,
South of the
lake
glacial
alluvial
and colluvial
border, lllinoian deposits
consist of few and small areas of sediments that
posited
in ice-front lakes
Loveland
Silt,
which
is
were de-
and of patchy occurrences of the
largely
colluvial deposits resting directly
and overlain by Wisconsinan
composed of loess and
on the bedrock surface
areas.
the bed-
relief
of about 400 feet
in a half
Saline
suggests a late stage of rejuvenation.
The steeper
slopes of the inner walls of the valleys, the
sected,
may
formable
The topography of the Shawnee
Hills
is
almost entirely the
stream erosion. The major features appear to have
surface
northern slope of the Shawnee
Hills
only
in
a
few
locali-
largely dis-
on which the Mounds Gravel of the
deposited. The only remnant of
in the Shawnee Hills is on the top of the
Shawneetown at the extreme eastern end of
and south of the glaciated area. The absence of
the area
Depositional glacial features are found on the
now
the gravel found
systems were diverted by glaciers, some were modified and
initiated following
surface. This surface,
Embayment Region was
ridge north of
were
of the intervalley ridges, and the
have been inherited from the major uncon-
developed before lllinoian glaciation, but some drainage
valleys
levels
of major valleys suggest upwarping of a rela-
tively flat erosion
glaciation.
in
of 100 to 200 feet (30 to 61 m)
loess.
PHYSIOGRAPHIC RELATIONS
many minor
steepness of
a mile.
parallelism
enlarged, and
relief
A maximum
roughly concordant
result of
the
County the relief is 600 feet in a little more
The valleys have narrow bottomlands which
broaden to as much as a quarter mile on the lower slopes.
The ridges between the valleys have less slope, but no flat
upland tracts remain on the northern slope of the Shawnee
Hills. The steeper slope of the inner walls of the valleys
in
than
deposits.
of
mile occurs at several places near the divide, and at Horton
Hill
lllinoian drift
because
parallelism
the slope. The streams are sharply entrenched
rock and have a local
lllinoian in age
and
have a dendritic pattern, but the major valleys have
Hills
the gravel elsewhere
tion,
may be
attributed to a lack of deposi-
but the relation to the gravel
Region suggests that
a
in
the
Embayment
prominent erosional surface was not
ties—on the flatter areas near the base of the northern slope
far
and on the floors of
gravel deposition, probably in early Pleistocene time, can
of
a
few valleys occupied by tongues
Throughout the south-central
part
of
Illinois,
the
northward-dipping Pennsylvanian strata are truncated by a
IN
SOUTHERN
ILLINOIS
this surface after
found on the northern slope
The even greater relief on the southern slope of the Shawnee Hills resulted from the truncation
well account for the relations
ice.
HE GLACIAL BOUNDARY
above the present surface. Warping of
of the
Shawnee
Hills.
of the resistant Pennsylvanian sandstones and the
easily
more
eroded Mississippian limestone and shale formations.
The occurrence of glacial features in the lower parts of
the valleys on the Shawnee Hills indicates that the valleys
had essentially reached
their
glaciated
Loveland
Silt
beyond the
topography
the
on
boundary, and the sharp
glacial
incision of the streams into the
of
drift
patchy occurrence of the
the
surfaces,
plain immediately north
till
of the Shawnee Hills indicate at
cation
depths before the
However, the absence of
lllinoian glacier arrived.
many
maximum
least
by
strong local modifi-
erosion
since
development of the topography.
of
many
It
probably smoothed the
of the ridges between the northward-
in
most exposures of the
till
suggests that there
was no great amount of plucking by the
of Cedar Lake (see
margin of the
this
In
ice.
Near the
dam
7) the presence of large blocks of
fig.
Pennsylvanian sandstone
cation).
in
ice (J.
the
till
indicates major erosion
A. Lineback, personal communi-
of drift
hill
a
may
be landslide or erosional
distinctly glacial
south of the valley, noted by Lamar
just to the
(1925,
114) and shown on the Lick Creek Quadrangle
p.
map, may be
developed
also
is
weakly
in
the
mile (1.6
km)
preserved
Drury Creek
vicinity of Creal Springs, along
1
north of Giant City State Park, and along Cedar Creek
southeast of Etherton (geol. sec. 11).
its
most exposures the till is a pebbly, sandy, clayey silt.
is sufficiently abundant to impart a sticky plasticity
when wet, and a hard compactness when dry. Pebbles are
In
Clay
abundant— less than 10 percent. Cobbles are
few are present in most exposures, and
boulders are rare. The calcareous till is gray in a few of the
thicker exposures, but most of the exposed till is strongly
generally not
scarce, although a
oxidized tan and brown.
In a
few
Petersburg
erosive power.
localities deposits of silt separate the
the bedrock. These deposits are similar
which
Silt,
is
water-laid deposits and
CHARACTERISTICS OF THE DRIFT
probably
common
The
massive
loess, equivalent to
by
side the area covered
Thickness
the outer
1
to 2 miles (2 to 3 km), the drift
occurrence and rarely over 10 feet (3 m) thick.
perceptibly at the base of the
feet of drift
is
common
Shawnee
Hills,
is
patchy
It
in
thickens
and 30 to
immediately to the north, where
includes well-bedded
It
silts,
some of which
the Loveland
are
found out-
Silt
drift.
lithology of the drift
who
from
till
position to the
in
elsewhere at the base of
the Carbondale Quad-
in
rangle has been described in detail
50
A
remnant of morainal topography.
a
morainic topography
the lllinoian drift (geol. sec. 6).
In
appearance.
the valley of Grassy Creek (geol. sec. 5)
in
and ridges
locality the plunging of the ice over the
north valley wall of a westward-flowing stream probably
enhanced
A
ridges
most have
but
insignificant factor in
flowing streams, but the scarcity of boulders of the local
at the
few of these
Lithology
was probably an
Glacial erosion
bedrock
A
lllinoian
glaciation.
surfaces
map.
features,
by Lamar (1925,
116-
p.
numerous sections having interbedded
lenses of silt and gravel. He also noted that boulders of dark
igneous rocks were relatively more abundant in the western
123),
noted
part of the area than in the east.
the lllinoian drift has a characteristic, nearly flat surface.
Near the
drift border,
of somewhat thicker
Lamar (1925,
drift,
fig.
19) noted an area
which he thought probably
dicated the presence of a terminal moraine. That area has
been
intensely
eroded
and
generally
lacks
Mineral composition
in-
topography
Two
in
clay-mineral
different
distinctly
recognized
the
tills
along
indicative of a moraine, but the thicker drift could rep-
(table
resent the lower part of a morainic tract.
relatively high in kaolinite
1 ).
expandables, 45
percent
Topography
and
glacial
and
area, the
illite;
percent
of
till
the
are
drift
samples are
12 samples average 25
illite,
and
30 percent
kaolinite and chlorite. These include samples near Galatia
on the undissected
surfaces immediately north of the Shawnee Hills, very
little evidence of morainic topography has been noted on
Although
At the eastern end of the
compositions
border
the
features are present
the ridges and valleys
in
the Shawnee
Hills.
Perhaps the best
Omaha
in
the area of Lake Saline (Frye et
al.,
table 2, p. 30). In the western part of the area, the
to the margin of the drift
in
expandables;
ables,
is
lower
in kaolinite
1972,
till
close
and higher
10 samples average 45 percent expand-
40 percent
illite,
and
15 percent kaolinite and
on the tongues of drift extending up
the valleys in the Shawnee Hills. Several of these valleys are
now partly occupied by artifical lakes. The shores of the
lakes in a few localities fall close to the tops of the drift,
and ridges on the surface of the drift form small peninsulas
chlorite.
that stand out prominently along the branches of Lake of
nearest the ice margin, are of the low-kaolinite type; those
features are preserved
Egypt
in
Creeks, as
the valleys of Anderson, Sugar, and Dry Fork
shown on the
Goreville Quadrangle topographic
In
one exposure
present; the
In
till
both compositions are
is
at the base.
exposures near the Pulleys Mill exit of Interstate 57
(geol. sees. 2, 3), the
a
(geol. sec. 5)
with higher kaolinite content
samples from the southern exposures,
mile farther north are of the high-kaolinite type. The
southern exposure
ILLINOIS STATE
is
immediately below the loess
in a
GEOLOGICAL SURVEY CIRCULAR
high
511
area,
50
whereas the northern exposure
feet (15
high-kaolinite
is
from
a
stream cut
lower, well below the upland level, and the
m)
may
till
underlie the
with the lower
till
kaolinite content. In a boring at Carbondale, the bulk of
the
till
has the high-kaolinite composition, and only the
and
ation,
till.
therefore,
till,
dominates
till
is
probably the basal
the shallow expo-
in
sures close to the margin, except east of the Pulleys Mill
exposures
tends to the margin of the
boro
where the high-kaolinite
(geol. sees. 3, 6),
m) of
resent about 7 feet (2
ex-
till
an exposure at Murphys-
drift. In
samples of the low-kaolinite
(geol. sec. 9) the
till
rep-
and along Cedar Creek
till,
near the Mississippi Valley (geol. sec. 11), directly on the
margin of the
(3 to 4.5
drift,
the samples represent 10 to 15 feet
m) of low-kaolinite
samples of low-kaolinite
to 3 feet (0.3 to
1
m) of
In all
till.
other localities the
represent only the upper
till
it
indicate
by weathering,
only the
leaving
in
the
at
60 miles (97 km) north of the
least three
senting at
present
these
(J.
tills
drift border, drifts repre-
substages of lllinoian glaciation are
as high in kaolinite as the
at
western
it
Illinois
did at
and
Iowa
eastern
evidence of weathering has been observed between
No
with different clay-mineral compositions
tills
dark
Soil
ably do
readvances of the
ice front.
horizon
overlying
high-kaolinite
is
reddish-brown,
In
many exposures
till
is
the
is
generally
samples the calcite
unusually large
till
is
(geol. sees. 3, 9, 10, 11).
till
thin and entirely leached.
strongly
oxidized.
partially leached,
amount of
secondary carbonates.
B
clayey
very
about 5 feet (1.5 m) of leached
calcareous
Sangamon
1 m)
and
In
in
a
The
few
others an
the B horizon
is
strongly
till,
prob-
sheets or even
local
much
of the earliest
glacier overrode Penn-
below the
till
The lower content of
is
lllinoian
till
is
the high-kaolinite
till.
kaolinite in the marginal drift
western-derived
is
not present
in
montmorillonite, but montmorilsignificant quantity in the
bedrock
or other drift formations overridden by the glacier. In
(geol. sec. 3).
plain
perhaps related to dilution by expandable clay minerals,
lonite
manganese and iron oxides
where the
glacial features are preserved,
by an abundance of black nodules,
and streaks of
to a
tills
The composition of the lower,
characteristic of
The
the two
regions
in
Illinois
where the
some
glacier overrode thick loess
deposits that are derived from western sources, a high con-
origin
tent of expandables occurs in the lower part of the
The
in
a high
restricted
is
drift,
till
which has
immediately north of the border region, where depositional
largely
lenses,
till
sylvanian sediments.
calcite indicates the presence of
In places
not represent separate
lllinoian drift in the area
mottled with bright red splotches, usually accompanied
Age and
margin of the
belt at the
of a
has a strongly developed
and
(Willman
Frye, 1970).
consists of 2 to 3 feet (0.6 to
till
is
maximum
its
Liman Substage, the earliest llits maximum westward extent
the
in
linoian substage, as
of
the border
no correlation between them
present
southern extent
narrow
commonly
in
till
apparent; however, the ice probably reached
in
None
A. Lineback, personal communication).
is
and
region,
State Geological
Illinois
content of expandable clay minerals,
The top of the
more
of
lag
Clinton and Marion Counties,
the border region. Because the upper
that
of that glaci-
been almost entirely washed away or
exists, has
Recent work by others
the two
Weathering
older glaciation
till
resistant boulders.
1
till.
much
a
appears that the
it
Survey has shown that
communication).
The high-kaolinite
The low-kaolinite
if
destroyed
upper few feet have the low-kaolinite composition (H. D.
Glass, personal
may
1970)
Frye,
of greater extent, but
drift marginal to the glacial
border has long been con-
sidered to be lllinoian (Leverett, 1899), largely because of
the absence of any recognized major drift border in the
region south of the border of Wisconsinan drift.
The
but
in
the Shawnee
Hills area the upper
till,
has the higher
till
content of expandable minerals.
It
seems possible, therefore, that the marginal part of
soil
the lllinoian glacier was covered by loess having a high
drift has a thickness
percentage of expandables, which was the continuation of
and characteristics comparable to those of the Sangamon
the Loveland Loess then accumulating beyond the glacier.
profile
Soil
on
on the outer margin of the
lllinoian drift
elsewhere
in
strongly developed than profiles
western
Illinois
Illinois. It is
much
on the Kansan
less
drift
in
and adjacent parts of Missouri and Iowa.
account for the complete change
Because of intense erosion during Sangamonian and
perhaps Yarmouthian time, preservation of very old drift
on the steep northern slope of the Shawnee Hills is not
likely. Kansan drift buried by lllinoian drift has not been
positively
identified
nearer than 25 to 30 miles
(40 to
48 km) north of the southern border of the drift, but
remnants of an older glaciation may yet be found beneath
lllinoian drift
in
the border area.
found south of the
The scattered boulders
lllinoian drift in
southern
Illinois
and
southeastern Missouri (Lamar, 1925; Flint, 1941; Willman
THE GLACIAL BOUNDARY
IN
SOUTHERN
ILLINOIS
The loess could have become mixed with ablation materials
on the thinning margin of the stagnant ice. This would
in
composition
at the
margin, where the loess would have been thickest and the
ice thinnest.
The
relatively small quantity of the
the expandable clay minerals and
region, farthest
sippi Valley,
absence
from the source of the
soon
after
till
with
the eastern
loess in the Missis-
lllinoian glacier dissipated
reaching
its
supported by the general absence of
maximum
glacial
the outermost part of the drift, the short
lakes,
in
support this interpretation.
The concept that the
stagnation
its
and the abrupt termination of the
life
ice
extent
by
is
landforms on
of the frontal
advance when
it
encountered the northern slope of the Shawnee
much
general smoothness of
The
Hills.
of the lllinoian surface, how-
from that of other areas of stagnation which
ever, differs
have abundant water-deposited features related to melting
ice
blocks (Jacobs and Lineback, 1969). The southernmost
may
lllinoian ice, therefore,
it
have been unusually thin, and
melted too rapidly to develop distinctive stagnation
features. This evidence favors a rapid advance, perhaps a
which would account for the
surge,
glacier's
advancing
The lower
part of the Peoria Loess
total loess
bluffs.
calcareous for roughly
than 10 to 15 feet (3 to 4.5 m)
less
is
leached from the entire loess
the carbonates are
thick,
section;
some exceptions
are near the
Mississippi
bluffs,
where the upper leached zone has been thinned by erosion.
The characteristics of the loesses are described in many of
the geologic sections (app. 2).
A
Roxana
the
Loveland
advance of the
lllinoian glacier, underlies
outside the area covered by the glacier. The
was intensely weathered to a red or reddish-
Silt
Silt
brown clayey
mon
which was deposited
third loess, the Loveland Silt,
largely during the
Distribution and thickness
is
8 to 10 miles (13 to 16 km) back from the bluffs, but
where the
unusually far south.
CHARACTERISTICS OF THE LOESS
from the
distance, generally less than a mile back
silt
with a very clayey B horizon (the Sanga-
comparable to that on the
Soil)
The
lllinoian drift.
Loveland overlies deeply weathered bedrock, generally
Except where
it
has been eroded along valleys, loess covers
the drift north of the glacial boundary and the bedrock
south of the boundary. Where deposited on relatively
back from
gressively
flat
its
source areas
Wabash, and Ohio Valleys. The
loess
is
the Mississippi,
in
as
much
as
100 feet
(30 m) thick at a few places on the Mississippi bluffs, but
50
feet
more common.
is
thins eastward to about
It
feet in 5 miles (8 km), 12 feet in 10 miles,
15 miles.
It is
(fig.
2).
as thin as
northward
ary turns
4 to 5 feet where the
in
25
and 8 feet
in
bound-
glacial
southeastern Williamson County
North of there, the
feet thick for
loess continues to
be 4 to 5
about 20 miles. Where the border of the
turns easterly, the loess begins to thicken, and
about 15 feet on the Wabash Valley bluffs
at
drift
reaches
it
New
Haven.
In
much
is
covered by the sediments of Lake Saline rather than
by
4, 6),
of the area near the Wabash Valley, the boundary
but
exposures
removed
Although
loess
slopes, sheetwash
the surface material on nearly
is
slopes.
into thick accumulations
silt
The dominant
plain sediments in the valleys
silt
is
material in the flood-
derived from erosion
Because the dominant winds are westerly,
from the
Mississippi
silt
blown
Valley forms the bulk of the loess
some
was extensively eroded and entirely
At its maximum development in
Silt
much
thinner than the Wisconsinan loesses and probably
was not over 10 to 15
may
feet (3 to 4.5
m)
thick. Therefore,
it
not have been over a foot or two thick along most of
the glacial boundary, which would account for
its
extensive
removal by erosion.
The Loveland Silt, which has a well-developed red
Sangamon profile, is about 1 .5 feet (0.5 m) thick along U.S.
Highway 51 in Union County, a short distance south of
the Jackson County line (SW SE NE 5, 11S-1W, Makanda
Quad.). About 1.5 feet of strongly weathered silt, probably
Loveland,
exposed
is
NW SW
3,
in
a
roadcut southwest of Creal
11S-5E, Johnson Co., Creal Springs
Quad.).
The
similar to those
at Gale
in
exposed
are not well
loesses
in
the Mississippi
boundary, but they probably are
bluffs near the glacial
p.
of the loess.
shale in
the Mississippi bluffs, the Loveland appears to have been
and slumping on many of the steeper
slopes has concentrated the
on the lower
all
on
areas.
large
in
Springs (SE
loess.
overlies a clayey residuum
it
(geol. sec. 1).
The Loveland
protected from erosion, the loess thins pro-
surfaces and
a
red clayey rubble of Pennsylvanian sandstone (geol. sees.
exposed
a
few miles south of the boundary
Alexander County (Frye and Willman, 1960,
13; Frye, Glass, and Willman, 1962).
composition of the
loess
in
southern
The thickness and
Illinois
been
has
described also by Fehrenbacher and others (1965).
15 to 20 miles (24 to 32 km) of the Wabash
to within
Valley, which then
becomes the major source of the
loess
(Glass etal., 1968).
GLACIAL LAKES
Stratigraphy
The
advancing southward up the slope of
lllinoian glacier
the Shawnee Hills blocked the northward-flowing streams,
Two
loesses are present in
to light-brown
silt
is
dark-brown, more clayey
dominantly
many
exposures.
An upper
silt
Roxana Silt, which is
The Roxana Silt commonly
is
loess in this area.
the
forms the lower one-fourth to one-third of the
but
it
not present
is
calcareous
but the
10
in
tan
the Peoria Loess, and the underlying
in
some
localities.
Both
Silt
becomes noncalcareous
(fig.
1).
Stratified
silt
in
the sharply incised valleys
overlain
reached
its
maximum
extent, and
indicate that the lakes extended
loesses are
ice front
in
a short
by
till
in
several
valleys
indicates the existence of lakes in the valleys before the ice
total loess,
the thick section on the Mississippi bluffs,
Roxana
and many lakes were formed
silts
over
till
the valleys as the
melted back.
Water-laid
localities
similar
down
deposits of sand,
indicate
ILLINOIS STATE
the
silt,
presence of
and clay
lakes
in
in
the
a
few
valleys
GEOLOGICAL SURVEY CIRCULAR
511
beyond
maximum
the
but such
extent of the glacier,
deposits would have been easily eroded, and they seem to
have been generally washed out of the valleys since the
ice
shown
quite as large as
areas
through
figure
in
and figures 4
1
7.
East of the glacial lakes
mapped
(fig.
1),
the ice front
Other remnants of lake sediments are probably
turned northward and the tributaries on the southern side
present but buried by the loess or by the waters of three
of the South Fork Saline River were not blocked by the
melted.
man-made
large
The
lakes.
possible
the glacier
extent of the lakes
dammed by
based on the assumption that the position of
is
the ice front
correctly
is
mapped and
that the lowest outlet
channel, either across divides or along the ice front, con-
maximum
the
trolled
of the lakes. Because of the
level
steep slopes of most of the valley walls, the lakes could
have
maximum
had
without
A
ice.
maximum
much lower than
levels
changing
significantly
the
indicated
(3
km)
Of the outlets thus predicated, only the outlet of the
easternmost lake to Maple Branch
(fig.
4) has walls that
strongly suggest erosion by water flowing through
The
it.
a
may
have existed
(fig. 4).
in
A
may
lake
have
also
the southwestward-trending
ice,
could have been blocked by glacial outwash at
it
mouth
were
the headwaters of
was not quite reached by the
valley that apparently
but
in
southern tributary to Sugar Creek, 2 miles
east of Creal Springs
later
its
the South Fork Valley. Both of these valleys
in
flooded during Wisconsinan time by Lake Saline.
West of the
glacial lakes
down Cedar Creek
extended
the lakes.
lake
existed 2 miles farther east
by
covered
areas
small
Brushy Creek,
mapped (fig. 1), the ice front
more than 2 miles (3 km)
for
before turning up the tributary of Bear Creek (Desborough,
1961).
Till
was observed by MacClintock (1940) near the
mouth of Bear Creek.
A
extension of the ice across
slight
now mapped
Water Valley and Cobden Cols could have been outlets,
Cedar Creek Valley, the area
but
would have blocked Cave Creek and formed a lake in its
valley. The lllinoian surface in the valley was probably
definitive
lack
particularly
characteristics,
erosional
from
features that should distinguish the spillway ravines
as
the normal erosional characteristics of other nearby ravines.
much lower than
The other
could have been preserved below the alluvium.
even
between
outlets, along the ice front
lakes, are
and the topography does not indicate
less distinctive,
their precise location,
which on the sloping divides would
be sensitive to the precise margin of the
may
ice
soon
stagnation,
large,
have been relatively thin and because
maximum
the
reaching
after
extent,
would have limited the contribution of water to melting
of the ice in the outer few miles of the glacier. This suggests
a brief interval
maximum
of
temporary existence of
supply of water to the lakes,
a high-level stage,
little
lakes.
The
had unstable
lakes probably
is
erosion
hundred
because
understandable
of the
the area of high relief during the
in
thousand
between
years
the
in
because no
The absence of these
shoreline features have been found.
features
levels,
the
intensity
one-third mile (0.5
(SW SE
17,
If
elevation
is
the
a lake
would
level
of a
km) southwest of Natural Bridge
10S-2W, Jackson Co., Pomona 7.5-minute
The low elevation of this col is attributed to
as mapped by Desborough (1961). Because there
fault,
a
is
no definite evidence that Cave Creek Valley was blocked by
ice, or of lake sediments to confirm its presence, no
the
lake
was mapped
in
that valley.
Very small, temporary lakes may have formed along
the southwestern tributaries of Bear Creek, but probably
no other lakes were present
(2.4
km)
in
the remaining
1.5
miles
to the Mississippi River bluffs.
Glacial
Lake Sugar
lllinoian
glaciation and deposition of the cover of Wisconsinan loess.
The
its
of
more than one
end of
Cave Creek Valley,
Quad.).
discharge
of water through the outlets, and thin sediments
in
the present surface, and lllinoian drift
not have exceeded 480 feet (146 m), which
col
ice.
The volume of meltwater may not have been
because the
was formed
alluvium,
The easternmost valley
was Sugar Creek
clearly
dammed by
the lllinoian
escaped back northward beneath the glacier. The drainage
formed Lake Sugar
in Williamson and Jackson Counties (fig. 4). Lake Sugar
would have received meltwater from about 3 miles (5 km)
from the eastern
of ice front, rainfall from about 22 square miles (57
much
of well-defined
absence
of the meltwater and
outlets
rainfall in
suggests
that
the catchment basins
would eventually have reached the
margin of the ice along the South Fork Saline River in
Williamson County and that from the western lakes would
lakes
have reached the margin of the
in
ice
along Big
the Mississippi Valley near Fountain Bluff
Some
may have
of the lakes
Muddy
glacier
of land surface, an
Valley, which
unknown
discharge from Lake
As the lowest
col
on the southern divide
(210 m), 2 miles (3 km) east of Tunnel
drained entirely through
Wagon
)
to
the west, and rainfall on the glacier.
Valley
(fig. 1).
km 2
(178 m) on the eastern divide at
New
Hill,
is
at
690
feet
and 585 feet
Burnside, the outlet
subglacial channels, particularly during the declining stages
of the lake must have been along the lower course of Sugar
when
Creek where the bedrock surface was
likely
the
level
in all
ice, at least
of
difficult,
was below any possible discharge
surrounding
occurred
by the
tence
water
the
across
lengthy
but
it
ridges.
lakes
very
the northward-flowing valleys blocked
during the advancing stage
when main-
channels would
have been
subglacial
is
Nevertheless,
doubtful that
THE GLACiAL BOUNDARY
IN
all
of them occupied
SOUTHERN
ILLINOIS
low
as
at
an elevation
about 520 feet (158 m). The boundary of the
as
lake,
drawn on the assumption that, at its maximum
its surface was as high as 510 to 520
feet (155 to 158 m). At that level, it would have been 20
to 25 feet (6 to 8 m) below the Maple Branch outlet
therefore,
level,
is
the elevation of
11
Southern border of
lllinoian glaciation
a
Till
or boulders
exposed near border
CZHD
^——^
y-
Possible glacial lake
Lake Saline
Present
.R3E|R4E
man-made
lake
Figure 4. Glacial boundary and ice-front lakes— eastern area.
12
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
channel through which water discharged from Lake
Wagon
front, and in a
is
distinctive morainal front along the border of
the ridge extending from near the outlet of Lake
boundary between Williamson and Johnson
Counties to Creal Springs, about 3 miles. Although this
ridge
may be bedrock
controlled
northwestward
the
across
part,
in
its
projection
now occupied by Cana
bedrock valley
if
Creek, a tributary of
correct, requires the existence of
with as
filled
much
100
as
At
its
maximum
ice front.
feet (30
m) of
southern extent the lllinoian glacier
The creek entrenched
channel
walled
northeastward
Pennsylvanian
in
from
about 5 miles
in
narrow, steep-
a
extending
sandstone
southeast of Creal Springs for
just
km)
(8
itself
Fork Valley. This
to the South
soil
bedrock and overlain by
in
loess,
as
developed on the
roadcut 2 miles
a
east of Creal Springs (cen. S. line
NE NE
30, 10S-
3E, Williamson County, Crab Orchard 7.5-minute Quad.).
Similar soils seem to be generally lacking on the bedrock
in
is
The
the glaciated area northwest of Sugar Creek.
relatively thin
and leached
in
loess
and the sub-
this region,
divisions cannot be differentiated readily in
many
Sangamonian or
could
not
likely
is
at an elevation of
540
feet (165 m), almost
(12 m) above the Lake of Egypt
in
(0.4 km) west of the outlet.
is only a quarter mile
The highest water level in the lake was probably not over
550 feet (168 m) and at that elevation it had a maximum
depth of about 80 feet (24 m) at the ice front.
The generalized border of the ice, as previously drawn,
although
less
than
a half mile farther
south than the present
boundary, would cover the ridges between the branches of
the lake considerably higher than 550 feet (168 m),
quiring separate lakes
and the Wagon Creek headwaters.
in
Cache Valley, and
would require the
this
to 2 miles
1
(1 .6
to 3
km)
ice front to
have
farther south along the
where no evidence of glaciation
The absence of well-defined drainage
dividing ridges in an area
has
been
found.
channels across the divides and the absence of even foreign
pebbles
0.8
exposures only a quarter to
in
km) south of the deposits of
till
a half
mile (0.4 to
noted by MacClintock
(1940) favor the continuity of the lake at the lower
with connections
ice
level
narrow channels along the tongues of
in
that extended up the valleys.
The Maple Branch
outlet
is
only about
a quarter mile
pre-lllinoian. Nevertheless, the area
wide and does not appear to have been deepened more than
10 to 15 feet (3 to 4.5 m), in part because of the low
was
gradient on the discharge side. This seems to indicate a very
have been glaciated after the
soil
low discharge even for the normal precipitation
flakes of foreign materials
and
in
the loess or
bedrock surface strongly suggests that the
soil
or on the
lllinoian glacier
did not cross the present valley of Sugar Creek.
it
seems
few years
likely that the outlet
in
the area,
was not used more than
(165-to-168-m)
Lake Wagon
level.
maximum
extent.
The
rapidity
melted back from the position
Lake Wagon
(fig.
5) existed in the headwaters of
fact that the slightly
is
further indicated by the
eroded Maple Branch outlet remained
the only outlet
Wagon Creek were blocked by the advancing lllinoian
glacier. These tributaries are now occupied in part by Lake
of Egypt, which extends 3 miles (5 km) farther northwestward within the glaciated area to a man-made dam across
the South Fork. Lake Wagon extended southward from the
ice front along Wagon Creek and up the tributaries of Dry
divide until the ice melted back about 5 miles (8
its
Such
THE GLACIAL BOUNDARY
IN
SOUTHERN
ILLINOIS
low discharge from the lake suggests the need
Evaporation would seem to have
been entirely inadequate to have lowered the lake
significant
and pre-
a
for alternative outlets.
cantly
ice front
km) from
a discharge route along
the eastward channel of the South Fork Saline River.
and the headwaters of Wagon Creek. The lake took the
km) of
the area east of the Big Muddy-Saline
maximum extent and opened
Fork Creek, Sugar Creek, Anderson Creek, Beaver Creek,
drainage from about 5 miles (8
in
its
with which the glacier
the South Fork Saline River where several long tributaries
of
a
was filled to the 540-to-550-foot
This would support other evidence
after the lake
that the ice stagnated almost immediately after reaching
Glacial
re-
each valley except Beaver Creek
in
formed, and the complete absence of even pebbles or small
Glacial
40
Wagon Creek,
which
places.
Consequently, the strong profile of weathering could be
either
outlet
extended
Exposures southeast of the diversion channel along
km)
The
feet
the lake to have discharged over the southern divide to the
of Creal Springs.
Sugar Creek show a very clayey red
km) southwest
11S-3E, Johnson County, Creal
3,
shown by
valley, as
rary diversions caused isolated bedrock knobs, the largest
a half mile east
1
that tempo-
later
in fact,
(W /2
In any case, the branches
Dry Fork Creek, Sugar Creek, and Anderson Creek
would have drained westward to the same outlet. The water
level would have to have reached over 700 feet (213 m) for
narrow channel was eroded deeply enough to be occupied
by Lake Saline (fig. 4).
The ice front was very close to the
few exposures of till; it was so close,
lake had an outlet 2.5 miles (4.0
Sugar Creek, which flows into the South Fork Saline River.
apparently diverted Sugar Creek northeastward along the
(3
The
of Creal Springs
Springs 7.5-minute Quad.) to Maple Branch, a tributary of
or just west of Creal Springs.
drift at
ice
glacier's surface impractical
position
the South Fork. Cana Creek was later occupied by Lake
Saline. This diversion,
segment of the
of Sugar
Creek blocks the probable course of Sugar Creek to the
broad valley
north of the Saline-Cache divide to the
)
to estimate.
at the
directly
an area of approximately 25 square
in
fell
The most
Wagon
a
km 2
miles (65
the drift
a
cipitation that
Lake Sugar.
into
in
the climate of that
time. The
volume of meltwater and
ward under the
ice
signifi-
possibility that a
rainfall
drained north-
along the pre-lllinoian bedrock channel
13
14
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
more
of the South Fork seems
channels to drain
glacial
trenched
A
likely.
network of sub-
the valleys, which are en-
all
bedrock, would have been needed. The drainage
in
would have taken a circuitous route of 12 to 15 miles
(19 to 24 km) as much as 4 miles behind the ice front
before discharging at the front of the glacier where it
South
crossed
Fork drainage near Palzo
in
River
about 400 feet (122 m)
is
the
in
that point, but the
at
valley
are
Wisconsinan and
Holocene (Lake Saline) deposits, and the
was somewhat lower, perhaps
is
at
the bedrock surface, which
about 375 feet (114 m). This yields
m
15 feet per mile (1.9 to 2.8
Maple Branch outlet. The
(0.9 to
m
1.3
a gradient
km) from the
per
of 10 to
level
of the
gradient of the bedrock surface
in
South Fork would be 5 to 7 feet per
this interval of the
mile
lllinoian surface
per km);
either case, the gradient
in
would have been adequate to carry
water through even
a small
volume of
a significant
As soon
as
the water
Little Saline.
feet
ice
northward, when
miles
would have connected with
of Middle Wolf Creek.
the valley
The
retreated about 2
front
possible
along the
(34 m) lower
of
outlet
is
Lake
at
km)
Saline eastward
Little
Lake Wagon
front to
ice
(3
a lake in
it
a
110
level
feet
not marked by a clearly established channel
comparable to the Maple Branch Outlet. The steep ravine
through the northwest quarter of Sec. 12, T. 11
is
S.,
R. 2 E.,
is
perhaps
along the probable margin of the ice and
adequate to account for the descent of
m/km). The
mile (21
level
of Lake
Wagon
lake
1
10 feet
in
about
a
would not have lowered to the
had retreated about
until the ice front
2 miles. Subglacial drainage from Lake Little Saline would
have required a channel
at
the base of the glacier about 3.5
km) long to connect with
carrying discharge from Lake Wagon.
miles (5.6
a subglacial
channel
channel. The pre-lllinoian valley
Lake Panther Den
through subglacial channels could have been interrupted
Glacial
Lake Panther Den
at times.
of several valleys, one
noticeably restricted by a
fill
bedrock
and
along the
below 650
fell
only outlet would have been beneath the
Its
the
until
ice
Glacial
is
level
(198 m), the lake would have been isolated from Lake
Williamson
County, only 8 miles northeast of the Maple Branch outlet
of the lake. The elevation of the present South Fork Saline
uppermost deposits
Creek.
valley,
of drift at several localities
in
these places discharge
(fig. 6)
existed in the headwaters
named Panther Den Creek, from the
divide between Wolf Creek and Middle Wolf Creek to the
Lake
Glacial
divide between branches df Little Grassy Creek a half mile
Little Saline
(0.8
Lake
Glacial
Saline
Little
Creek
Little Saline
Saline drainage
in
(fig.
5) occupied the valley of
the extreme southwestern part of the
system, separated
by prominent divides
from the Cache River drainage to the south and
from the Big Muddy drainage to the west. The
largely
ice front
which Lake
Lake
low col
relatively
of
the Saline-Cache divide
in
Goreville
21,
(center
County, Goreville, 7.5-minute Quad.),
680
in
feet (207 m),
the divide
less
is
marked by
than
a
a steep
11S-2E,
at
a
mile
Johnson
quarter mile south of the tip of
would have
required advance of the ice front about a half mile (0.8 km)
farther south than presently drawn, which does not seem
the
lake,
likely,
but discharge through
a
across Grassy Creek, and the eastern branch of Little
Grassy Lake, which was formed by a
dam
across Little
Grassy Creek.
and
Meltwater
precipitation
trapped
in
this
area
have drained westward into the western branch of Little
surface.
A
now
an elevation of
three miles of ice front and seven square miles of land
southwest
that area are
V-shaped reentrant
would have taken the drainage from
Saline
Little
feet
would have
front to Lake Wagon.
Little Saline
discharged eastward along the ice
in
Muddy-Cache Divide,
2 to 4 miles (3 to 6 km) to the south, would have come
from 10 miles (16 km) of ice front and 20 square miles
2
of land surface. The lowest points in the divide
(52 km
are at an elevation of about 700 feet (213 m) in the eastern
divide, 750 feet (229 m) in the southern divide, and 675
feet (206 m) along the ice front in the western divide.
The latter, therefore, controlled the highest level for a lake
along this part of the ice front. A lake at that level would
ward from Goreville to an elevation of about 650
a level at
and
east of the meeting of Jackson, Williamson,
occupied by Devils Kitchen Lake, which was formed by
dam
appears to have surmounted the ridge extending northeast-
(198 m),
km)
Union Counties. Several of the valleys
this outlet
between the
front and the Big
ice
)
Grassy Creek, which
1
the ice front (S /2 31, 10S-1E, Williamson County,
Makanda
7.5-minute Quad.) shows no evidence of unusual deepening
or scouring, and,
although not impossible.
had an outlet through the Water
Valley Col at 575 feet (175 m). The possible outlet along
if
the lake ever attained such
a level,
it
places along the divide near the ice border. Consequently,
At two other localities
the ice appears to have crossed divides between the valleys
at approximately the same elevation (575 feet
175 m]). If
Wolf Creek, west of the
the lake level did not reach this height, three lakes would
The
Big
elevation of the divide
Muddy
drainage
is
low
as
as
between the Saline and
650
a lake at that level in the valley of
divide,
Little
would have been continuous with the
lake could
Saline drainage. This
westward because
700
feet (198
feet
a ridge
m)
at
two
lake in the
not have drained
continuously over an elevation of
(213 m) separates Wolf Creek from Middle Wolf
THE GLACIAL BOUNDARY
IN
SOUTHERN
ILLINOIS
did so for only a very short time.
[
have existed
in
this
area at lower levels until the ice
treated from the divides and the single
level
lake formed
re-
at a
perhaps 100 feet (30 m) lower.
In
this area, also, the
possibility of a
major drainage
15
o
16
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
favored by the lack of a definite outlet
Creek 3 miles (5 km) south of the col contained none
most of the meltwater and rainfall escaped
beneath the ice, no single large lake would be required, but
of the minerals that characterize the glacial deposits; how-
beneath the
channel.
at
ice
is
If
seven lakes would have existed at a lower level
least
along the ice front
would require channels along
all
the valleys joining a major subglacial channel along Wolf,
Grassy, and
Grassy Creeks, continuing along Crab
Little
Orchard Creek to the Big Muddy, and thence to the margin
of the glacier
Mississippi Valley near Fountain Bluff, a
in
distance of at least 30 miles (48 km), but not
behind the
more than 6
front.
Because of the sharp pre-
lllinoian relief, the subglacial
channels would have to have
miles
ice
followed at or very close to the bedrock surface
pre-existing valleys. This
Almost immediately
the
in
difficult in the advancing
and could account for very brief high-level
stage
lakes.
might
after stagnation began, drainage
have become connected through widening crevasses
well
and around isolated
have acted as a
At places the pre-glaciation
ice blocks.
Grassy Creek Valley was
as
seems
dam
with
filled
until outlets
which
drift,
drift,
would scarcely be
likely
because the lake
Devils
Kitchen Lake.
have been clear. Although definite evidence that the col was
the spillway of a lake
is
may
lacking, the col
have served
by
Lamar (1925).
The existence of Lake Antioch, perhaps at a lower
level, is supported by the presence of sand and clay deposits
along the west bank of Little Grassy Creek (N /2 12, 11S1W, Union Co., Makanda 7.5-minute Quad.) at an elevation
of 540 to 550 feet (165 to 168 m) (Lamar, 1925, p. 151).
It would require a retreat from the maximum position of
the ice front of about 1.5 miles (2 km) for Lake Antioch
to have merged with the west arm of Lake Panther Den,
and about 8 miles (13 km) to have merged with the remainder of Lake Panther Den, although by that distance
that purpose for a short time, as originally suggested
1
the lake would have been reduced to a
level
of about 450
feet (137 m).
Lake Antioch and Lake Wagon seem to support more
definitely than the other lakes the presence, at least
tempo-
of high-level lakes south of the ice front. In these
rarily,
channels
areas subglacial
may
not have been adequate,
or were completely shut off for a longer time than
Lake Antioch
Glacial
Lake Antioch
6) occurs in the
(fig.
Grassy Creek,
Little
now
partly
and
rainfall
drainage
1
of land surface. Because of
low
its
level,
It
mile of ice
km 2
from about 7 square miles (18
however,
)
could
it
have received overflow from Lake Panther Den to the east
at its
maximum
possible level of
Lake Indian to the west
625
at
its
675
feet (206
maximum
m) and from
Lake Indian
Glacial
Lake Indian
ice
is
named
for the Antioch
Cemetery on
called
is
Water Valley, formerly the
named
site
for
of a
school, a mile southwest of the col. Drainage southward
Bradshaw Creek,
into
of the
a tributary
Cache River, which flows into the Ohio River.
(0.4
At the maximum advance of the
within Giant City State Park.
ance of an erosional channel, but without evidence of
less
covered with thick
related to relatively
loess,
and
Its
no bedrock outcrops,
original
low
level
may be
deep erosion of fractured rock along
projected by
The sand from
much
a
Lamar (1925).
IN
SOUTHERN
mile of ice front and
Lake
ILLINOIS
It
took meltwater from
rainfall
less
from about three
A
shallow col marks this position (SE SE
Probably very
did, drainage
little
water discharged through
must have been beneath the
surrounding divides are
much
ice,
in
to
junction with Drury Creek, 6 miles (10
the
none
Indian Creek at a
level until
maximum
If
melting of the ice opened the entire valley
lower
its
it.
because the
higher.
Lake Indian would have existed
the
NW
10S-1W, Jackson Co., Makanda 7.5-minute Quad.).
stage drainage
sample of alluvium along Bradshaw
THE GLACIAL BOUNDARY
a
Antioch.
than 20 feet (6 m). The outlet
boulders, or gravel were noted.
a fault, as
lllinoian glacier,
At the highest level, 620 feet (189 m), Lake Indian
would have drained eastward along the ice front to Lake
36,
The outlet surface is flat for nearly a quarter mile
km) and slopes slightly southeast. It has the appear-
deepening, probably
is
much
glacial material.
square miles.
the Water Valley Col by Lamar (1925),
is
about three-
material, but similar material along the creek
quarters of a mile below the boundary contained
named
col
a quarter
mile outside the glacial boundary, did not contain glacial
than
from the
lllinoian
Indian occupied only an area about a mile long, entirely
glacial lake
locality
was formed when the
Jackson County. Alluvium up the valley, only
the ridge between the two branches of the lake. The outlet,
the
(fig. 6)
blocked Indian Creek near the southeastern corner of
possible level of
feet (191 m).
The
Glacial
the
in
had an elevation of only 575 feet (175 m).
would have received meltwater from only
front
Little
gap
a
Muddy and Cache
southern divide between the Big
it
the
western branch
occupied by
Grassy Lake. Because of an outlet through
areas,
in
intervening valleys.
Glacial
of
the
at
front would have been nearly 100 feet (30 m) deep and
the 2
in
km) below the man-made dam forming
(3
may
also
were cut through the
the sharply incised segments of the valley
in
miles
ice
the water discharged through the Water Valley outlet would
the area of Lake Panther Den.
in
Subglacial drainage
ever, they
km) north of
position of the ice front, and during this
would have
to have been entirely beneath
ice.
17
Southern border of
lllinoian glaciation
Till
or boulders
exposed near border
( -
~~z
^^>ir?
Probable glacial lake
Present
man-made
lake
Figure 7. Glacial boundary and ice-front lakes— western area.
18
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
Glacial
have lowered Drury Lake to that
Lake Drury
Cobden
Lake Drury
Glacial
easternmost lake
Drury Creek Valley was the
(fig. 7) in
Muddy
the Big
in
Drainage area, and
it
appears to have been the largest of the lakes formed along
the front of the lllinoian glacier. At
600 to 605
level,
maximum
its
(183 to 184 m),
feet
projected
Cobden and about 3
the ice front to the outlet at
(5
km) wide. At the
ice front
150
have been about
from about 4 miles
carried meltwater
it would
would have
It
km) of
(6
km 2
and precipitation from 20 square miles (52
beyond the
miles
along Drury Creek,
(46 m) deep.
feet
would have been 585
)
ice front
of surface
maximum
feet (178 m), at
evidence
it
would
by
Col, deeply mantled
loess,
shows
deepening by through-flowing water,
of
was probably short and
the volume of water low. Otherwise, a more significant
channel would have been eroded in the descent of the
outlet river 185 feet (56.4 m) in about 1 .3 miles (2.1 km).
As the outlets seem inadequate for the overflow of
and the time
it
served as a spillway
such a large lake, a considerable proportion of the drainage
ice front.
The outlet at Cobden is a long shallow col with two
branches which would have isolated as an island a large part
of the area occupied now by Cobden. The overflow would
have been into the headwaters of the Cache River and
thence to the Ohio River. The col could very well have
carried discharge from the lake. The relatively low elev-
may
vation of the col, like the Water Valley Col,
in
consid-
probably was subglacial, northward along Drury Creek to
the channel of Crab Orchard Creek and thence to the Big
Muddy
Valley and the front of the ice
A
lake probably continued at a lower level in Drury
about
ice front
Creek Valley during the retreat of the
8 miles (13 km) to Crab Orchard Creek, by which time the
lower parts of Crab Orchard and Big
mapped
probably free of
due to the presence of faults, which were
that area by Lamar (1925). The thick loess
the Mississippi
in
Valley.
erable part be
in
level
level.
The Cedar Creek
little
of Lake Drury
level
which
as indicated for the
have covered nearly as large an area
600-foot (183-m)
abandoning the
level,
the ice did not block drainage through
If
the Cedar Creek outlet, the
would have
it
covered an area approximately 6.5 miles (10 km) long from
outlet.
Muddy
Valleys were
ice.
cover, thicker there than farther east, prevents examination
of the bedrock floor of the outlet. Well-bedded
silt
under-
Roxana Loess in the area of the lake a mile northeast of Cobden (center SW 20, 11S-1W, Union Co., Makanda 7.5-minute Quad.) at an elevation of 585 feet
Lake Clay Lick
Glacial
lying the
(178 m) could have been deposited
(sample P-7772)
is
much
loess (samples P-7773, P-7774), and,
Sangamon
loess
Soil
the lake, but the
in
if
lllinoian in age, the
must have been eroded from
it
before the
was deposited.
A
(0.8-m) boulder of dark igneous rock
2.5-foot
the southern bank of Cache River 3 miles (5
of the col was interpreted by Lamar (1925,
been carried across the col
Drury, glacial erratics should be
but only
p.
151) to have
ice.
common on
all
common
in
on
km) southeast
block of
a floating
in
icebergs carrying glacial debris were at
lake,
silt
weathered than the overlying
less
If
Lake
the area of the
few have been observed. An alternative
a
would
boulder in Cache Valley to
which may have transported the
igneous boulders and cobbles encountered on the upland
interpretation
a
pre-lllinoian
relate the
glacier
farther southwest, in Perry and
Missouri
Cape Girardeau Counties,
1941). Transportation of the boulder in
(Flint,
Cache Valley by man from the glaciated region about 10
miles (16
km) north seems
upland
in
ice
glacial
the
up the main creek and
Creek.
A
creek
(SW
Quad.),
12,
its
of that
(fig.
7),
valley,
thus
which extended
tributaries, including
Clay Lick
man-made dam across the
10S-2W, Jackson Co., Pomona 7.5-minute
large lake
is
headwaters
Lake Clay Lick
formed by
a
called Cedar Lake.
The elevation and extent of the lake is uncertain bewould have drained along the margin of the ice
it
against the south wall of Cedar Creek Valley. The elevations
of knobs of till on the valley floor are as high as 470 feet
(143 m) and the maximum level of the lake probably would
not have exceeded 500 feet (152 m). It could have been
cause
lower
is
if
much
of the drainage escaped beneath the
ice.
This
not too unlikely because the glacier would not have had
to occupy completely
to account for the
lake
ice
till
more than
that
still
a mile of the valley floor
remains
in
front
and about 30 square miles (78
The
km) of
the valley.
would have received drainage from 4 miles
km 2
(6
)
of land
at
600
feet
must have crossed Drury Creek to the
the southwestern part of the Carbondale Quad-
rangle (Sees.
20 or 21, 10S-1W, Jackson
Co.). Otherwise,
the lake would have had an outlet at 585 feet (178
(NW%
blocked
probably
forming
surface.
less likely.
For the elevation of the lake to have been
(183 m) the
The presence of a considerable body of till at two localities
on the floor of Cedar Creek Valley suggests that the glacier
20,
10S-1W) along the
ice front across
between Drury Creek and Poplar
Camp
m)
the divide
Creek, a tributary
of Cedar Creek, which drains directly to the Mississippi
Valley
(fig.
1).
A
slight
withdrawal of the
THE GLACIAL BOUNDARY
IN
SOUTHERN
ice front
ILLINOIS
would
19
APPENDIX
1.
Clay-mineral and carbonate compositions of samples.
Carbonates
Clay minerals (%)
(coilr its/sec)
Sample
Geologic
number
section
Expandables
lllite
kaolinite
Calcite
Dolomite
P-2519
P-2520
P-7743
P-7744
P-7746
P-7748
3
49
47
45
45
23
36
38
42
40
55
15
23
6
15
13
-
P-7749
P-7754
2
10
23
57
P-7755
P-7756
5
36
32
45
43
47
45
47
32
46
40
38
43
40
40
34
42
23
50
Chlorite and
3
3
3
2
2
7
5
P-7776
P-7777
P-7779
11
11
9
P-7787
10
P-7796
Roadcut east side of Creal Springs,
SE SE NW 25, 10S-3E, Williamson Co.,
Creal Springs Quad.
Roadcut one-fourth mile north of cross-
P-7799
roads at Dykersburg,
Analyses by H. D. Glass,
21
15
15
?
22
16
20
18
28
20
30
26
17
?
25
26
29
15
10?
17
-
17
14
13
15
19
26
27
NW NE SW 35,
10S-4E, Williamson Co., Carrier
NOTE:
74
-
25
Illinois
Mills
Quad.
State Geological Survey. Locations of geologic sections given
APPENDIX
2.
in
appendix
2.
Geologic sections.
Thickness
Thickness
in feet
in feet
SAHARA
Cutbank
NO. 5 MINE SECTION
at
edge of
strip
NW SW NW
ary road northwest of plant,
9S-5E, Saline Co., Carrier
Illinoian Stage
Glasford Formation
mine, west side secondMills
29,
Quad.
Wisconsinan Stage
light-gray
streaks
along
mine
spoil
bank
Till,
clay
and
a
brown, massive; contains
few manganese-iron pellets
(P-7803 middle)
plastic;
till
massive, compact;
tan,
(P-7747 from
inter-
1.5
silt)
cobbles to
igneous
10 inches
in
di-
5
base at creek level (P-7746 at base)
1.5
PULLEYS MILL EXIT SECTION
Roadcut
Carbondale Formation
silt,
top, relatively
ameter; streaks of small pebbles are contorted;
Pennsylvanian System
Clay and
at
at base, less
calcareous, blue-gray to tan, silty, massive;
contains
RoxanaSilt
noncalcareous,
3
brown (P-7743
3.5
calcareous,
tongued with
joints;
(P-7804 2 feet above base)
Silt,
calcareous, light
Silt,
surface soil at top overlain by
some
Till,
soft)
Peoria Loess
gray-tan,
leached, rusty brown, clayey
compact than below; P-7749
Pleistocene Series
Silt,
Till,
abundant
Illinois
Highway 148, % mile
(0.4
km)
northwest of Interstate 57, 1.5 miles (2.4 km)
red to red-brown, microblocky,
nodules and manganese-iron
northwest of Pulleys
Mill,
SW NW NE
28, 10S-
2E, Williamson Co., Goreville Quad. Described
Sangamon B horizon developed on shale
with possibly some Loveland Silt at top (P-7802
streaks;
in
1966.
middle)
3
Shale, gray-green, plastic (P-7801)
0.5
Pleistocene Series
Wisconsinan Stage
Peoria Loess
GRANGE CHURCH SECTION
Silt,
Cutbank, south side tributary to Wolf Creek, NE
NW 21, 10S-2E, Williamson Co., Marion
top in B horizon of Modern Soil; P-2525 3 feet
above base; P-2524 1 foot above base)
SE
Quad.
Pleistocene Series
Wisconsinan Stage
Peoria Loess, slumped
20
Silt,
noncalcareous, brown (P-2526 2 feet below
8.5
Roxana Silt
darker brown than above; contains strong
manganese-iron splotches; indistinct contact
top (P-2523
1
at
foot above base)
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
1
.5
511
Thickness
Thickness
in feet
in feet
lllinoian Stage
noncalcareous,
Till,
many
silty;
A
exposed and probably eroded
above base)
0.5
noncalcareous, very clayey, brown to red-
brown
with
bright
red
Petersburg
contains
splotches;
Silt,
manganese-iron nodules, pellets, and streaks; B
horizon of Sangamon Soil (P-2521)
noncalcareous, tan to
Till,
light
brown
contains igneous pebbles to 2 inches
P-2519
in
at base)
NW
in
(P-7743
P-7744
till
1.5
P-2745 leached
1.5 feet above P-7744)
7.
HICKORY GROVE SCHOOL SECTION
Quad.
Pleistocene Series
2
lllinoian Stage
Glasford Formation
Silt, noncalcareous,
massive, gray-brown, gray
and greenish tan mottled and streaked; surface
soil in upper part has a dark-brown B horizon
(P-7739 8 feet below top; P-7740 10 feet below
top)
Till,
cemented
Soil
foot below top)
at
silt;
top
from lower
Silt,
to light brown, mottled
gray-brown; indistinct platy structure; contains
1
lower part;
in
are mostly Pennsylvanian sandstone
.11
lower part (P-7741
tan to light brown, gray-tan
contains a few rotten granite pebbles but pebbles
Roxana Silt
reddish brown
is
and limonite-
red-brown B horizon of Sangamon
not completely exposed (P-7754
15
part)
Good exposures
.75 mile southeast from here
and extending for 1.5 miles (2 km) show no till
and Peoria Loess on moderately weathered
.
lllinoian Stage
sandstone
Glasford Formation
Till,
3
GOREVILLE NORTH SECTION
Peoria Loess
in
4
Pleistocene Series
Wisconsinan Stage
pebbles
non-
Roadcut Interstate 24 at underpass of Illinois
Highway 37, 2 miles north (3 km) of Goreville,
SW SE SE 3, 11S-2E, Johnson Co., Goreville
Quad. Southernmost exposure of till along I-24
Roadcut on side road west of Interstate 57,
SE NE NW 28, 10S-2E, Williamson Co., Goreville
compact,
contains a few small sandstone pebbles (P-7751
one foot above P-7750)
Pennsylvanian System
Caseyville Formation
Residuum of angular, red to red-brown sandstone
pebbles and cobbles in matrix of tan silt and
sand (Yarmouth Soil) (P-7750 from matrix)
Weathered Peoria Loess above till
till 1 mile (1.6 km) northSE NE 20, was sampled in 1976
feet below top of calcareous till;
till;
platy,
and fine sand, tan-brown, massive, compact,
noncalcareous; gradation at top and bottom;
1
top of calcareous
at
but
Silt
Another exposure of
west
10
Silt
5
top;
at
foot
1
calcareous (P-7752)
diameter;
secondary carbonates (P-2520
contains
massive
gray,
(P-7753
2.5
calcareous, gray; not very pebbly but
Till, silty,
igneous pebbles and cobbles; upper part
darker and softer; Sangamon Soil B horizon not
horizon of Sangamon
Soil (P-2522)
fill,
noncalcareous, brown, compact; contains
Till,
Glasford Formation
clayey, mottled red-brown, gray-brown, and
brown; contains numerous brown clay-skins up
mm thick; deeply weathered (P-7742) ....
to 2
8.
.0-2
Pennsylvanian System
Sandstone weathered red-tan to brownish red
COBDEN NORTHEAST SECTION
Roadcut .75 mile (1.2 km) northeast of Co Jen,
SE NW SW 20, 11S-1W, Union Co., Makanda
Quad.
1
-
Pleistocene Series
5.
CHITTY CEMETERY SECTION
Borrow
pit
in
isolated
Grassy Creek, SE SE
Co., Lick Creek
SW
Wisconsinan Stage
on north side of
hill
Peoria Loess
25, 10S-1 E, Williamson
Silt,
ous, massive compact;
Quad.
calcareous, tan to light brown,
com-
and a 1-foot
boulder (P-7755 near base; P-7756 from highest
part of exposure where weakly calcareous) ....
Soil and loess eroded at top
igneous
a
7
Roxana
Glasford Formation
contains
top has
Soil at
above base)
lllinoian Stage
pact;
Modern
clayey, tough, blocky B horizon (P-7774 4 feet
Pleistocene Series
Till, silty,
gray, mottled dark gray and tan, noncalcare-
Silt,
by
pebbles
a
Silt
brown, massive, noncalcareous; separated
slumped area from the underlying beds
2
lllinoian Stage?
Pearl
.10
Silt,
Formation?
gray, bedded, noncalcareous;
some
thin beds
are clayey, others have very fine sand; base at
6.
PULLEYS MILL SOUTHEAST
Roadcut
level
km) northSE 3, 1 mile
of bedrock nearby (P-7772 middle)
1.5
Interstate 24, 0.2 mile (0.3
Illinois Highway 37, NE SW
km) southeast of Pulleys Mill,
Johnson Co., Goreville Quad.
west of
(1.6
11S-2E,
First
roadcut
south
of
Big
Murphysboro and borrow
Pleistocene Series
south southeast of road,
pit
NW
Muddy
River
at
225 feet (69 m)
SW SE 8, 93-2W,
Jackson Co., Pomona Quad.
lllinoian Stage
Glasford Formation
THE GLACIAL BOUNDARY
MURPHYSBORO SOUTH SECTION
IN
Pleistocene Series
SOUTHERN
ILLINOIS
21
Thickness
in feet
Wisconsinan Stage
Peoria Loess
compact, noncalcareous; thick B horizon of Modern Soil at top (P-7783 5 feet above
P-7782)
Silt, tan,
Roxana
Silt,
12
Silt
brown, compact, noncalcareous; columnar
and vertical jointing; top gradational
structure
(P-7782)
3
lllinoian Stage
Glasford Formation
Till,
tan to light brown, noncalcareous, compact,
contains
massive;
chert,
quartz,
and
igneous
pit
(P-7781
top at floor of borrow
4 feet above P-7780)
pebbles;
6
some
Sand, noncalcareous, tan; contains
silt;
slumped and thickness uncertain (P-7780)
and
clayey, moderately compact; at level of bedrock
3
top exposed across the road (P-7779)
1
partly
Till,
10.
calcareous, gray to greenish gray, silty
JONES QUARRY CREEK SECTION
Roadcut
T
at
junction,
NW SW
SE
18,
9S-2W,
Jackson Co., Pomona Quad.
Pleistocene Series
lllinoian Stage
Glasford Formation
Till,
noncalcareous, red to red-brown, clayey,
microblocky; B horizon of Sangamon
Soil;
top
eroded (P-7789 3 feet above P-7788)
Till,
noncalcareous, tan to
compact,
silty
light
2
brown, massive,
and clayey (P-7788 2
feet
above
and
silty;
7787)
3
calcareous,
Till,
gray-tan,
clayey
contains few small pebbles (P-7787)
11.
1
ETHERTON SOUTHEAST SECTION
Roadcut north side Cedar Creek valley, 1.75
miles (2.8 km) southeast of Etherton, NW NE SW
11, 10S-2W, Jackson Co., Pomona Quad.
Pleistocene Series
lllinoian Stage
Glasford Formation
Till,
noncalcareous, reddish tan; blocky vertical
clevage; fewer pebbles than below; lower part of
Sangamon
B
horizon
which
is
truncated
by
sloping surface (P-7778 5 feet above P-7777)
2
compact; contains
more pebbles than below (P-7777 5 feet above
noncalcareous,
Till,
gray,
P-7776)
Till,
5
calcareous, gray, massive, compact;
clayey
more
and more pebbly than below (P-7776
10 feet above P7775)
Till,
calcareous,
compact,
8
gray
and
brown;
prominent color banding; contains small pebbles
(P-7775at base)
5
more than 15 feet thick is exposed
roadcuts northward up the valley slope
Peoria Loess
in
22
ILLINOIS STATE
GEOLOGICAL SURVEY CIRCULAR
511
.
REFERENCES
Desborough, George A., 1961, Geology of the Pomona Quadrangle,
Illinois: Illinois
State Geological Survey Circular 320, 16 p.
Wright, George Frederick, 1890, The glacial boundary
Pennsylvania,
Ohio,
Kentucky,
Geological Survey Bulletin 58,
De Wolf, Frank W., 1917, Geologic map of
12
and
in
western
Illinois:
U.S.
p.
(1:500,000):
State Geological Survey.
Illinois
Fehrenbacher,
B.,
J.
L.
J.
and R. T. Odell,
and southScience Society of America Proceedings,
White, H.
1965, Loess distribution
western Indiana: Soil
v.
Illinois
1
Indiana,
Ulrich,
P.
southeastern
in
Illinois
29, no. 5, p. 566-572.
Richard Foster, 1941, Ozark segment of Mississippi River:
Flint,
Journal of Geology,
v.
49, p. 626-640.
C, H. D. Glass, and H. B. Willman, 1962, Stratigraphy
and mineralogy of the Wisconsinan loesses of Illinois: Illinois
State Geological Survey Circular 334, 55 p.
Frye, John
Frye, John
C, A. Byron Leonard,
H. B. Willman, and H. D. Glass,
Geology and paleontology of late Pleistocene Lake
Saline, southeastern Illinois: Illinois State Geological Survey
1972,
Circular 471
44
,
p.
C, and
Frye, John
H.
Wisconsinan Stage
Willman, 1960, Classification of the
B.
in
the Lake Michigan glacial lobe:
Illinois
State Geological Survey Circular 285, 16 p.
C, and
Frye, John
B„
et al.,
Illinois
State
H. B. Willman, 1967, in Willman, H.
map
1967, Geologic
of
(1:500,000):
Illinois
Geological Survey.
John C. Frye, and H. B. Willman, 1968, Clay mineral
indicator of Midwest loess: in The
Quaternary of Illinois: University of Illinois College of Agri-
Glass, H. D.,
composition, a source
culture Special
Publication
14,
Survey Reprint 1968-W, 6
logical
35-40;
p.
Illinois
State Geo-
p.
Jacobs, Alan M., and Jerry A. Lineback, 1969, Glacial geology of
the Vandalia,
Circular 442,
Lamar,
E.,
J.
Illinois, region:
24
State Geological Survey
1925, Geology and mineral resources of the Carbon-
dale Quadrangle:
172
Illinois
p.
Illinois
State Geological Survey Bulletin 48,
p.
Leighton, M. M., and
Illinois:
J.
A. Brophy, 1961, lllinoian glaciation in
Journal of Geology,
v.
69, p.
1899, The Illinois
Survey Monograph 38, 817 p.
Leverett, Frank,
sheet
in
Illinois:
drift
State
Illinois
-31
glaciai
MacClintock, Paul, 1940, The southern
till
1
lobe:
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THE GLACIAL BOUNDARY
IN
SOUTHERN
ILLINOIS
23
ILLINOIS INSTITUTE OF
NATURAL RESOURCES
STATE OF ILLINOIS, ILLINOIS STATE GEOLOGICAL SURVEY DIVISION
Printed by authority of the state of
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