Surficial Geology of Crab Orchard Lake Quadrangle, Williamson County, Illinois

              Illinois Geologic Quadrangle Map
IGQ Crab Orchard Lake-SG
Base map compiled by Illinois State Geological Survey from digital data provided by the
United States Geological Survey. Topography compiled 1963. Planimetry derived from im-agery
taken in 1993. PLSS and survey control current as of 1996. Partial field check 1996.
North American Datum of 1927 (NAD 27)
Projection: Transverse Mercator
10,000-foot ticks: Illinois State Plane Coordinate system, east zone (Transverse Mercator)
1,000-meter ticks: Universal Transverse Mercator grid system, zone 16
Recommended citation:
Follmer, L.R., and W.J. Nelson, 2010, Surficial Geology of Crab Orchard Lake Quadrangle,
Williamson County, Illinois: Illinois State Geological Survey, Illinois Geologic Quadran-gle
Map, IGQ Crab Orchard Lake-SG, 1:24,000.
Geology based on field work and data analysis by Leon R. Follmer and W. John Nelson,
2001–2004.
Natural Resource Conservation Service staff, Carbondale office, assisted with field work
and the drilling of stratigraphic test borings.
Digital cartography by Jane E. J. Domier, Jennifer E. Carrell, Amanda Tovey, Joseph B.
Magnotta, and Daniel R. Stevenson, Illinois State Geological Survey.
The Illinois State Geological Survey and the University of Illinois make no guarantee,
expressed or implied, regarding the correctness of the interpretations presented in this
document and accept no liability for the consequences of decisions made by others on the
basis of the information presented here. The geologic interpretations are based on data
that may vary with respect to accuracy of geographic location, the type and quantity of
data available at each location, and the scientific and technical qualifications of the data
sources. Maps in this document are not meant to be enlarged.
IGQ Crab Orchard Lake-SG
SURFICIAL GEOLOGY OF CRAB ORCHARD LAKE QUADRANGLE
WILLIAMSON COUNTY, ILLINOIS
Leon R. Follmer and W. John Nelson
2010
1½ °
APPROXIMATE MEAN
DECLINATION, 2010
MAGNETIC NORTH
TRUE NORTH
ROAD CLASSIFICATION
Primary highway,
hard surface
Secondary highway,
hard surface
Light-duty road, hard or
improved surface
Unimproved road
State Route
ADJOINING
QUADRANGLES
1 De Soto
2 Herrin
3 Johnston City
4 Carbondale
5 Marion
6 Makanda
7 Lick Creek
8 Goreville
BASE MAP CONTOUR INTERVAL 10 FEET
NATIONAL GEODETIC VERTICAL DATUM OF 1929
1 2 3
4 5
6 7 8
© 2010 University of Illinois Board of Trustees. All rights reserved.
For permission information, contact the Illinois State Geological Survey.
1000 0 1000 2000 3000 4000 5000 6000 7000 FEET
1 .5 0 1 KILOMETER
SCALE 1:24,000
1 1/ 2 0 1 MILE
Institute of Natural Resource Sustainability
William W. Shilts, Executive Director
ILLINOIS STATE GEOLOGICAL SURVEY
E. Donald McKay III, Director
For more information contact:
Institute of Natural Resource Sustainability
Illinois State Geological Survey
615 East Peabody Drive
Champaign, Illinois 61820-6964
(217) 244-2414
http://www.isgs.illinois.edu
Williamson County surficial geology and 7.5-minute quadrangles.
MARION
HERRIN
PITTSBURG
CRAB ORCHARD
JOHNSTON
CITY CRAB ORCHARD
LAKE
HARCO
DE SOTO
CARRIER
MILLS
GOREVILLE
LICK
CREEK
CARBONDALE
CREAL
SPRINGS
STONEFORT
MAKANDA
Equality–fine
Equality–silty
Equality–sandy
Disturbed ground
Cahokia Fm
Teneriffe Silt
Pearl Fm
Glasford Fm
Glasford Fm–
stratified
loess
bedrock
water
0 2 4 6
MILES
"e 35547 Stratigraphic boring with continuous samples of
surficial sediments examined by the authors
Contact
Data Type
Note: Numeric labels indicate the county number, a portion of
the 12-digit API number on file at the ISGS Geological Records
Unit. Online well and boring records are available from the ISGS
Web site.
c
dg
ls
&
g
g(s)
pl
Interpretation
Made land; mostly strip mines,
includes disturbed land and
reclaimed land
Alluvium; mostly formed during
post-glacial times (Holocene);
largely derived from eroded Peoria
loess; mildly weathered and
leached; weakly developed soil
profile in the upper 5 feet; underlain
by Equality clay or fine sand at
lower elevations and by bedrock at
higher elevations
Weathered loess, 4 to10 feet thick
containing well-developed modern
soil (Alfisol) overlying Pennsylva-nian
bedrock; contains three loess
units distinguishable where thick:
upper–Peoria Silt, yellowish brown
to gray with strong pedologic
structure (Modern Soil); middle-
Roxana Silt, reddish brown to
reddish gray with weak pedologic
structure (Farmdale Geosol);
lower–Loveland Silt, pale brown to
dark gray with strong pedologic
structure (Sangamon Geosol);
Peoria and Roxana occur at most
locations; Loveland is often absent;
loess units largely distinguished by
pedogenic features and cover most
upland areas of county; bedrock
exposure up to 20% of map unit
Glacial fluvial and lacustrine
deposits of Illinoian age covered by
4 to 10 feet of loess; upper part
contains Sangamon Geosol; forms
several undifferentiated terrace
levels, producing a stepped
geomorphic surface; a facies
member with Glasford stratified
deposits (g(s)); formed during the
next to the last glaciation (Illinoian)
as the result of meltwater accumu-lation
General characteristics: Glacial till
and associated water-laid and mass
wasted deposits of Illinoian age
covered by 5 to 10 feet of loess;
largely derived from Pennsylvanian
shale; forms a veneer of glacial drift
deposits across the uplands of most
of Williamson County and fills in
preglacial valleys; loess cover thins
on sloping land along the southern
border of Williamson County; upper
part contains Sangamon Geosol;
divisible into two map units:
Glasford stratified deposits (g(s))
and Glasford till (g); upland end
member facies of Illinoian glacial
sequence
Ablation deposits; water trans-ported
and glacial debris-flow
deposits with soft-sediment
deformation features; likely contains
gravel at the base and overlies
dense basal till where glacial
deposits are thick; missing in places
where loess overlies eroded
bedrock (bench); laterally grades
into till (g) or Pearl Formation sand
(pl); largely restricted to discontinu-ous
terrace levels (localized level
areas) across the uplands at
elevations from 420 up to 550 feet;
formed on the Illinoian glacier after
stagnation; temporary ice-walled
lakes accumulated sediments that
formed terraces now buried by
loess; erosional benches common
in some areas that form a continu-ous
geomorphic surface with
terraces
Till; more dense and uniform than
diamicton in g(s); underlies most of
the gently rolling hills of the county;
variable thickness ranging from a
veneer of a few feet to over 100 feet
thick in buried valleys; upland facies
end member of Illinoian glacial
sequence, made up of map units g,
g(s), pl, and tr; discontinuous in
places because of fluvial erosion or
a nondepositional mode of the
glacier (glacial erosion)
Interpretation
Pennsylvanian sedimentary rock
with less than 4 feet of weathered
loess cover, mostly Peoria loess
containing well-developed modern
soil (Alfisol); discontinuous patches
of glacial deposits are common
QUATERNARY DEPOSITS
Unit
HOLOCENE STAGE (Present to 10,000 years B.P.)
Disturbed ground
Cahokia Formation
WISCONSINAN STAGE (10,000 to 75,000 years B.P.)
Loess over bedrock
ILLINOIAN STAGE (128,000 to 180,000 years B.P.)
Pearl Formation
Glasford Formation
(divided into two units)
Glasford
stratified deposits
Glasford till
PRE-QUATERNARY (PENNSYLVANIAN) DEPOSITS
Unit
bedrock
Material
Man-made deposits; mixtures of
loess, glacial deposits, shale, and
coal mine wastes
Silt-rich deposits ranging from
silt loam to silty clay; dark gray to
brown, mottled below 3 feet, totally
gray below 10 feet; weakly bedded
in lower part; gravel lenses in lower
parts of thick intervals; noncalcare-ous
matrix but contains secondary
calcite nodules below solum of soil
in places; ranges up to 30 feet thick
Silt loam to silty clay loam, up to
10 feet thick, overlying bedrock
typically sandstone or shale;
yellowish and reddish brown to
gray; strong pedogenic features,
structure, coatings, biopores, stains,
and concretions
Fine sand to clay loam covered by
weathered silt loam to silty clay
loam; yellowish brown to mottled
brown to gray; strong pedogenic
features and clay-rich in upper 10
feet; leached to a depth of about 20
feet below the ground surface;
calcareous and bedded in lower
part; commonly thin-bedded very
fine sand, well sorted with a few thin
lenses of silty clay; secondary
calcite common in the upper part of
the calcareous zone; thickness
uncertain, may range up to 50 feet
thick; beds of coarser sand and
gravel are expected near base of
unit
General features: Silty diamicton
dominated by silt loam and silty clay
loam with variable amounts of clay,
sand, and pebbles; covered by 5 to
10 feet of weathered silty clay loam
at most locations; brown to gray
colors with common yellowish and
dark mottles; strong pedogenic
features and more sand or clay in
upper 5 feet; leached to a depth of
about 20 feet below the ground
surface; stratified in places; dark
gray, compact, and unoxidized in
lower part, which commonly
contains detrital wood, pyrite, and
other oxidizable minerals; average
thickness 20 to 30 feet and can
exceed 100 feet thick in places;
pebble content from <1 to 5%,
dominated by Pennsylvanian
lithologies, mostly sandstone,
quartz, chert, and an assortment of
crystalline rocks
Stratified clay loam, silt loam to
silty clay loam with lenses of sand
and loamy diamicton; deformed
structures and variable fabric and
textures; few fining-upward trends in
places overlying sparse pebble
bands
Silty clay loam diamicton that
varies from pebbly silty clay to silt
loam diamicton; very few pebbles in
places; typical till fabric, compact
and uniform
Material
Dominantly sandstone with
lesser amounts of siltstone,
shale, mudstone, limestone, and
coal; covered by yellowish brown to
gray, weathered, silt loam to silty
clay loam up to 4 feet thick
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24027
24020