U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the GEOLOGIC INVESTIGATIONS SERIES U.S. GEOLOGICAL SURVEY ILLINOIS STATE GEOLOGICAL SURVEY MAP I–2669 (SHEET 3 OF 3) S S S S S TER TER TER TER TER 0 0 0 0 0 0 0 0 0 0 50 25 50 25 75 0 50 25 75 50 25 0 50 25 75 75 0 0 75 0 225 20 1 1 1 1 250 225 20 1 1 1 1 225 20 1 1 1 1 250 225 20 1 1 1 1 250 225 20 1 1 1 1 ME ME ME ME E' 89° 88° A' ME D' C' B'

Woodford Co.

A' B' C'

E' 150 D' Tazewell Co. E M INO 57 r L NK e WOODFORD CO. MORAINE v P i A Sibley 45 R M P MC LEAN CO. ack S CHATSWORTH MORAINE in E k a O 39 w e A EL PASO MORAINE 150 55 R M 54 e E iv O L r aw er RAINE g C n U X n ki N L i SECTION c 51 I SECTION SECTION a R r I-I' SECTION SECTION I O p I' Mackinaw River I-I' Mackinaw River M L T I I-I' E S I-I' I-I' S R 165 O 74 K L M A N A I M BLO A OM Danvers L BLOOMINGTON MORAINE IN O EUREKA MORAINE G 9 T N Mackinaw O M N 47 R E A A E O Sugar Creek M Normal F N I N R L I NE NORMAL MORAINE E I 115 40° 30' O T A CH A A 49 M E R R R I O S MO R IROQUOIS CO. A R N FLETCHERS MORAINE Iroquois Co. 9 A O M E k I I 9 FORD CO. Ford Co. r Bloomington N o N M E M B F O O ig E R E A F Paxton t I o Rankin s N N R u e E A r K E I Gibson City 9 E EUREKA MORAINE W EURE A D 9 k N i L A t e I ch L J' re A R I BLOOMINGTON MORAINE CHATSWORTH MORAINE 122 C R N P I TEM O A S M O I NORMAL MORAINE SECTION r N C X OR AL T YS a M O J-J' M N S g S u Y West Fork S 55 S S ILLIANA MORAINIC H B T M ON I LOO E

R MINGTON M O

L M O Ford Co. Ford Co. FORD CO.

E M R SHIRLEY MORAINE k R

r Y id A Champaign Co. Champaign Co. ELLIS MORAINE o k CHAMPAIGN CO. d A

F l MORAINE

e e OOMINGT 74 150 I

e re Sanga Fo I N SECTION l mo r N BL

d C n k CO. LEAN MC J-J' d R E

i i 45 E PAXTON MORAINE o M v

M o O e R 54 p A r

I V a N J k E 57 e c r

RA i m O I SECTION M N K SECTION SECTION SECTION E SECTION C i H-H' H ROY l H' H-H' LE ROY MORAINE H-H' H-H' E i H-H' L o MC LEAN CO. H n LE ROY MORAINE Middle Fork Vermilion River

I Middle Fork Kickapoo Creek M E A L R TAZEWELL CO. Le Roy ORAIN LI Heyworth A iv Tazewell Co. k M 47 N e LOGAN CO. ee h A r Logan Co. r itc Y C P D 136 SECTION O M 136 136 R A Sugar Creek HEYWORTH MORAINE J-J' H t ig O E E l B a Rantoul

L Y I R S G 40 40 40 40 40 W A

McLean Co.

I O MC LEAN CO. N McLean Co.

N LE ROY MORAINE k R E De Witt Co. E De Witt Co.

e I

T DE WITT CO. N C e I N r Atlanta H A I SHELBYVILLE MORAINE TION X 1

TION X 1 TION X 1 TION X 1 C TION X 1 L R o M A S S n O r g M M R Y a H Point Farmer City O S SECTION g E ek Cr u L e ee O O T J-J'

k GGERA B r TEM GGERA

S GGERA GGERA GGERA Y C R S E APPROXIMATE BOUNDARY VI R Salt Creek RANTOUL MORAINE L M M YS LE o A p OF WEDRON GROUP A S o o p o Kickapoo Creek a I I L n k N North Fork N r c i e U De Witt Co. ILLIANA MORAINIC v i K E E O h R R Piatt Co.

TICAL EXA c TICAL EXA

TICAL EXA TICAL EXA TICAL EXA M T i 74 n v

150 a e CHAMPAIGN CO. N r VERMILION CO.

55 r

O VER VER VER VER VER

A B

51 A

R 54 Mahomet R 49

N n A o e A m CH n a A i DE WITT CO. l I PIATT CO. g M n P B a A a N Lake Clinton I S S G R

N E Clinton Ten Mile Creek k U e E e M Lincoln r IN 48 C O 10 e A SECTION SECTION il R R SECTION SECTION SECTION M O G k A G' G-G' G-G' G-G' G-G' e M G-G' n H I re e T T R N C O E 47 E EYW r H Ogden Deer Creek ee N D 74 I 72 10 CHAMPAIGN MORAINE 121 A 10 150 Urbana Salt Creek Champaign St. Joseph R

G O o o CHAMPAIGN CO. Goose Creek se M

PIATT CO. k E C e r e e r LOGAN CO. N e C k Salt Fork I Salt Creek De Witt Co. 54 130 lt DE WITT CO. a P A Macon Co. S U Fork t OPE OF MACON CO. E al

R S

S SECTION R

Monticello E H

O k J-J' O e m Mount e I B W YVILLE MORAINE r b T

L XIMAL SL

Pulaski M C a Homer

U r

E D A r

PRO O 57 s a S SHELB M s Sangamon River d R N n r URBANA MORAINE 45 T e e 40° i D E r v R F i A

i T R v R

e H

I Tolono r A NE TUM MORAINE R O a R 49 i

E k 51 I O G s L 48 D M a M k L G s O I a T OF PESO E K 105 R

V CO. PIATT

121 72 CO. MACON A CRES Y R

SECTION SECTION SECTION SECTION SECTION I CERRO GORDO MORAINE I

F B N F' F-F' F-F' F-F' F-F' F-F' M D Lake Fork rk L r G Lake Fo e Bement E M LOGAN CO. E iv O O O E H R R Logan Co. on R R R F SANGAMON CO. S am A AR O Sangamon Co. g A M M R an E I A S Pesotum N RIDGE FARM MORAINE Lake C I E IN N Decatur E

E HILDRETH MORAINE Decatur B A E C D 0 0 0 A 0 0

E T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 D B 0 0 0 T T T C T 750 70 650 60 550 40 350 850 80 50 450 750 70 650 60 550 40 350 80 50 450 750 70 650 60 550 40 350 750 70 650 60 550 40 350 80 50 450 750 70 650 60 550 40 350 90 850 80 50 450 Base map sources: Drainage from USGS 1:100,000-scale Digital Line Graph files. County SCALE 1:250 000 90 850 80 50 450 FEE FEE FEE FEE FEE boundaries from ISGS and roads from Illinois Department of Natural Resources (IDNR); 5 0 5 10 15 20 MILES both data sets digitized from USGS 1:24,000- and 1:62,500-scale topographic maps. Municipal boundaries from IDNR, adapted from U.S. Census Bureau TIGER line files 5 0 5 10 15 20 25 KILOMETERS Universal Transverse Mercator projection Location of cross-section traverses. End moraines, a significant topographic feature on the cross sections, are shown for reference. Moraines are from a smaller scale map by Willman and Frye (1970). I E' D' Figure 17.—Cross sections along nine straight-line traverses and EXPLANATION OF STRATIGRAPHIC UNITS H along one traverse (section J–J’) that follows the Mahomet Bedrock Lake Clinton As shown in figure 17 (cross sections) and figures 18 and 19 C' Valley thalweg (the thalweg is the valley axis, connecting the deepest G J J' points along the valley). Cross sections were computed from the Wedron and Mason Groups, including Cahokia Formation BEND IN FEET SECTION ILLIANA MORAINIC SYSTEM METERS (Wisconsin and Hudson Episodes). This unit is assigned a mini- milion River

BEND IN three-dimensional model of stratigraphic units based on the elevation SECTION AIGN MORAINE 850 er eek maps shown in figure 14 (sheet 2). Difficulties were encountered in mum thickness of 15 ft F B' ON MORAINE TH MORAINE

Ford Co. 250 ermilion Co. TH MORAINE G-G' OR V mapping the stratigraphic unit comprising the Wedron and Mason CHAMP AXT P SECTION BEND IN

800 SECTION OR

TSW E ELLIS MORAINE A-A' eek Groups and Cahokia Formation, especially in the southwestern part Upper Glasford Formation (Illinois Episode) YW Ford Co. eek Piatt Co. SECTION Macon Co. eek HE CHA H-H' of the study area, where these sediments are thin or absent. To inte- Y MORAINE D-D' Champaign Co. B-B' 750 Piatt Co. SECTION Middle Fork V SECTION 225 SECTION Long Point Cr De Witt Co. McLean Co. BEND IN grate this unit with the upper Glasford Formation, which is in places SECTION Champaign Co. BEND IN CERRO GORDO MORAINE SECTION Sangamon River BEND IN G-G' SECTION Sangamon River eek LE RO BEND IN

SECTION A' BEND IN SECTION Upper Glasford basal sand SECTION North Fork

Salt Cr exposed, required assigning the Wedron and Mason Groups and D Macon Co. BEND IN BEND IN SECTION BEND IN SECTION De Witt Co. SECTION 700 C-C' Friends Cr BEND IN Kickapoo Cr SECTION SECTION H-H' Cahokia Formation a minimum thickness of 15 ft (see discussion on azewell Co. SECTION McLean Co. BEND IN E-E' SECTION T Sangamon River est Fork 200 sheet 1 under “An internally consistent geologic model and set of I' Sugar Cr SECTION 650 W Middle Fork maps,” fourth paragraph). This permitted a smooth integration of Lower Glasford Formation (Illinois Episode) the Wedron and Mason Group surface with the upper Glasford 600 Formation surface across the area. The assumption of a minimum C 175 Lower Glasford basal sand thickness also affects areas where modern streams have incised H' 550 Glasford Formation and older deposits; there, the top of the older deposits in these valleys has been effectively lowered by 15 ft, pro- Upper Banner Formation (pre-Illinois Episode) 500 150 ducing a minimum 15-foot thickness of Cahokia Formation alluvium in the riverbeds. The presence of Cahokia Formation alluvium is rea- 450 sonable and is generally supported by field observations. However, Middle Banner Formation—mostly Mahomet Sand Member (pre- B Illinois Episode) G' 125 as a consequence of the assumed minimum 15-foot thickness, thin 400 surficial deposits also are shown along valley margins where they Bedrock (undifferentiated) may not actually occur; in such places, modern erosion has locally 350 100 exposed upper Glasford Formation and older deposits. VERTICAL EXAGGERATION X 140 Figure 18.—Perspective-view fence diagram composed of cross sections F' A–A’ through I–I’ from figure 17. Stratigraphic units are the same as those A shown in the cross sections. Viewpoint is from the southeast. Vertical exag- geration approximately 85x. I I' FEET METERS TH MORAINE 900 ILLIANA MORAINIC SYSTEM OR EUREKA MORAINE TSW

850 ON MORAINE CHA AXT

SO MORAINE 250 P D-D' A SECTION FLETCHERS MORAINE

800 Ford Co. B-B' EL P McLean Co. eek ELLIS MORAINE C-C' SECTION Ford Co. Iroquois Co. SECTION

750 Mackinaw River 225 azewell Co. McLean Co. T Spring Cr Mackinaw River

700 A-A' SECTION

E-E' 200 650 SECTION

600 175 550

500 150

450

125 400 Land surface Elevation 700 ft Elevation 600 ft Elevation 500 ft

350 100 VERTICAL EXAGGERATION X 140

CREST OF LE ROY MORAINE

H ILLIANA MORAINIC SYSTEM H' AIGN eek FEET eek METERS

800 C-C' MORAINE milion River SECTION CHAMP Middle Fork er Salt Cr V McLean Co. D-D' J-J' Champaign Co.

750 SECTION B-B' 225 SECTION Kickapoo Cr ermilion Co. Elevation 400 ft SECTION eek A-A' V Sangamon River Champaign Co. SECTION 700 J-J' SECTION Sugar Cr

E-E' 200 azewell Co. est Fork

650 McLean Co. T SECTION Middle Fork W

600 175 550

500 150 Elevation 775 ft Elevation 675 ft Elevation 575 ft Elevation 475 ft 450

125 400

350 100 VERTICAL EXAGGERATION X 140

Lake Clinton Y AIGN

G AR G' Piatt Co. FEET TH METERS MORAINE B-B' CHAMP OR Elevation 375 ft 800 Champaign Co. SECTION YVILLE MORAINE eek YW TE BOUND North Fork MORAINE HE eek D-D' ermilion Co. V SECTION Champaign Co. 750 SHELB XIMA Saline Branch

WEDRON GROUP 225 Piatt Co. URBANA MORAINE C-C' J-J' De Witt Co. CERRO GORDO MORAINE J-J' OF SECTION SECTION Salt Cr SECTION en Mile Cr APPRO A-A'

700 T SECTION Salt Fork Sangamon River eek Logan Co. 200 650 De Witt Co. E-E' SECTION

600 Deer Cr 175 550 Elevation 750 ft Elevation 650 ft Elevation 550 ft Elevation 450 ft

500 150

450

125 400

350 100 VERTICAL EXAGGERATION X 140

Elevation 350 ft CERRO GORDO MORAINE F F' Y ermilion Co. AR FEET YVILLE METERS V Champaign Co. C-C' T RIDGE eek TUM MORAINE 750 ARM MORAINE B-B' SECTION 225 MORAINE MORAINE SECTION SHELB WES PESO A-A' Piatt Co. Piatt Co. TE BOUND RIDGE F Kaskaskia River Macon Co. 700 SECTION D-D' Champaign Co. Embarras River SECTION Friends Cr XIMA WEDRON GROUP

Sangamon River 200

650 OF APPRO E-E' Logan Co. Macon Co. SECTION 600 Lake Fork 175 Elevation 725 ft Elevation 625 ft Elevation 525 ft Elevation 425 ft 550

500 150

450 Figure 19.—Horizontal “slices” through the geologic materials in the map area, showing the stratigraphic units encountered 125 400 at different elevations above sea level. Viewpoint is from the south; vertical exaggeration is approximately 30x. Slices are shown from elevation 775 ft to 350 ft, in 25-foot increments. The upper left diagram shows the land surface, where ele- vations approach 950 ft; slices between 950 ft and 775 ft were omitted because they did not expose underlying units. 350 100 Stratigraphic units are the same as those shown in the cross sections. Note in particular the gradual filling of the Mahomet VERTICAL EXAGGERATION X 140 INTERIOR—GEOLOGICAL SURVEY, RESTON, VA—1999 Bedrock Valley, from pre-Illinois time into the Wisconsin Episode.

AUTHOR AFFILIATIONS THREE-DIMENSIONAL GEOLOGIC MAPS OF QUATERNARY SEDIMENTS IN EAST-CENTRAL ILLINOIS 1U.S. Geological Survey, 908 National Center, Reston, VA 20192 Email: [email protected] By 2Illinois State Geological Survey (emeritus) 1 1 2 3 3Illinois State Geological Survey, Natural Resources Building, David R. Soller, Susan D. Price, John P. Kempton, and Richard C. Berg 615 East Peabody Drive, Champaign, IL 61820 Email: [email protected] 1999