Illinois Preliminary Geologic MapIPGM Lacon-SG

Base map compiled by Illinois State Geological Survey from digital data provided by the United States Geological Survey. Digital Line Graph data from 1994.

North American Datum of 1983 (NAD 83)Projection: Transverse Mercator10,000-foot ticks: Illinois State Plane Coordinate system, west zone (Transverse Mercator)1,000-meter ticks: Universal Transverse Mercator grid system, zone 16

Recommended citation:McKay, E.D., III, R.C. Berg, A.J. Stumpf, and C.P. Weibel, 2007, Surficial geology of Lacon

Quadrangle, Marshall County, Illinois: Illinois State Geological Survey, Illinois Prelimi-nary Geologic Map, IPGM Lacon-SG, 1:24,000.

Geology based on field work by E.D. McKay, R.C. Berg, A.J. Stumpf, and C.P. Weibel, 2001–2003.

This mapping was funded in part by the Illinois Department of Transportation to support planning for upgrade of Illinois Route 29.

Digital cartography by J. Carrell, J. Domier and Z. Golshani, Illinois State Geological Survey.GIS support by P. Johnstone, L. Smith, and B. Stiff, Illinois State Geological Survey.

This Illinois Preliminary Geologic Map (IPGM) is a lightly edited product, subject to less scientific and cartographic review than our Illinois Geological Quadrangle (IGQ) series. It will not necessarily correspond to the format of IGQ series maps, or to those of other IPGM series maps. Whether or when this map will be upgraded depends on the resources and priorities of the ISGS.

The Illinois State Geological Survey, the Illinois Department of Natural Resources, and the State 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 loca-tion, the type and quantity of data available at each location, and the scientific and technical qualifications of the data sources. Maps or cross sections in this document are not meant to be enlarged.

IPGM Lacon-SG

SURFICIAL GEOLOGY OF LACON QUADRANGLEMARSHALL COUNTY, ILLINOIS

E. Donald McKay III, Richard C. Berg, Andrew J. Stumpf, and C. Pius Weibel2007

1 / °1 2

APPROXIMATE MEANDECLINATION, 2007

MA

GN

ET

IC N

OR

TH

TR

UE

NO

RT

H

ROAD CLASSIFICATION

Primary highway,hard surface

Secondary highway,hard surface

Light-duty road, hard orimproved surface

Unimproved road

State Route

ADJOINING QUADRANGLES1 Whitefield2 Putnam3 Florid4 La Prairie Center5 Henry6 Rome7 Chillicothe8 Washburn

BASE MAP CONTOUR INTERVAL 10 FEET

NATIONAL GEODETIC VERTICAL DATUM OF 1929

For more information contact:Illinois State Geological Survey 615 East Peabody Drive Champaign, Illinois 61820-6964 (217) 244-2414 http://www.isgs.uiuc.edu

1 2 3

4 5

6 7 8

Released by the authority of the State of Illinois: 2007

7000 FEET1000 10000 2000 3000 4000 5000 6000

.5 1 KILOMETER1 0

SCALE 1:24,0001/ 21 0 1 MILE

Illinois Department of Natural ResourcesILLINOIS STATE GEOLOGICAL SURVEY

William W. Shilts, Chief

References

Hansel, A.K., and W.H. Johnson, 1996, Wedron and Mason Groups: Lithostratigraphic reclassification of deposits of the Wisconsin Episode, Lake Michigan Lobe area: Illinois State Geological Survey, Bulletin 104, 116 p.

Willman, H.B., E. Atherton, T.C. Buschbach, C. Collinson, J.C. Frye, M.E. Hopkins, J.A. Lineback, and J.A. Simon, 1975, Handbook of Illinois stratigraphy: Illinois State Geological Survey, Bulletin 95, 261 p.

¹ Stratigraphic nomenclature follows that of Hansel and Johnson (1996) for Wisconsin and younger deposits and Willman et al. (1975) for deposits older than Wisconsin Episode; within each unit, the components are listed in order of decreasing abundance.

² Diamicton is a name for a unsorted or poorly sorted, sedimentary deposit that contains a wide range of particle sizes, such as a till that contains clay, silt, sand, gravel, cobbles and boulders.

&cm

t

h(m)

l-b

h(p)

p/t

c(f)

py

c(fp)

dg

p/l-b

QUATERNARY DEPOSITS

Unit

HUDSON EPISODE (~12,000 years before present (B.P.) to today)

Disturbed ground

Cahokia Formation(floodplain facies)

Cahokia Formation(alluvial fan facies)

Peyton Formation

WISCONSIN EPISODE (~12,000–75,000 years B.P.)

Henry Formation(Parkland facies)

Henry Formation(Mackinaw facies)

Batestown Member,Lemont Formation

buried by >5 feet of Peoria Silt

Tiskilwa Formation

buried by >5 feet of Peoria Silt

PRE-QUATERNARY

Unit

PENNSYLVANIAN PERIOD (~280–315 million years B.P.)

Carbondale and Modesto Formations

Interpretation

Deposits disturbed or modified by human activity in gravel pits, coal mine spoil banks, earthen dams, other excavations, and landfills

Alluvium (river sediment); post-glacial overbank deposits on floodplains, natural levees, and in backwater lakes; coarse deposits in channels, point bars, and tributary streams

Alluvial fan deposits; post-glacial redeposited loess and till in fans where streams and ravines emerge from uplands onto low-slope valley floors; subject to flooding

Slopewash, talus, rock-fall, and slump deposits on or at base of steep slopes in small coalescing fans along bluff of Illinois River valley; post-glacial; may be poorly consolidated and unstable

Sand dunes, dune fields and sheet deposits of sand eroded from underlying outwash and redeposited locally on Illinois River terraces and uplands; proglacial and post-glacial Fluvial (riverine) and ice-marginal outwash deposits in Illinois River valley in terraces, former bars and channels and locally in terraces along tributaries to Illinois River; deposited proglacially by meltwater from distant glaciers; not consistently differentiable from Illinois Episode sand and gravel of the underlying Pearl Formation where intervening tills are absent

Till and associated sediment derived directly from glacial ice; overlain by thin covering of loess; occurs east of the western edge of the Eureka Moraine; absent in the Illinois River valley and tributary valleys, where removed by post-glacial erosion

Till and associated sediment derived directly from glacial ice; exposed in gullies, excavations and along steep slopes where overlying Peoria Silt and the Batestown Member have been eroded; occurs throughout the uplands of the area; absent in the Illinois River valley and tributary valleys, where removed by post-glacial erosion; where lower part of the unit is gray, the Delavan Member can be differentiated, and where it contains common wood fragments, the Oakland Member can be differentiated.

Interpretation

Lithified marine, estuarine, deltaic, fluvial and swamp deposits

Description1

Areas of disturbed earth and/or removed earth; grain size ranges from clay to gravel, and may include waste or other rubble

Silt and clay with local surface occurrences of sand and gravel; typically grades at depth to sand or sand and gravel, which may be indistinguishable from Henry Formation; stratified, brownish gray to gray; 5 to 50 feet thick

Silt and silty clay, interbedded with fine sand, and locally gravel and redeposited bedrock clasts; brownish soft to moderately stiff gray; calcareous or non-calcareous; typically overlies Cahokia or Henry Formations; interfingers with Cahokia floodplain facies; 5 to 30 feet thick

Silt, clay, sand, gravel and diamicton; unstratified to crudely stratified; yellowish brown to brownish gray; may include bedrock clasts; overlies Cahokia, Henry, or older glacial drift or bedrock; interfingers with Cahokia; 5 to 25 feet thick

Sand; very fine to fine, well-sorted, and loose; yellowish brown to grayish brown; calcareous in lower part; conformably overlies Henry Formation; 5 to 15 feet thick

Sand and gravel with cobbles and boulders; stratified; yellowish brown to grayish brown; calcareous; usually clean and moderately well sorted; unconformably overlies older sand and gravel deposits, glacial diamictons², or bedrock; 10 to 20 feet thick in tributary valleys and 10 to 80 feet thick in Illinois River valley

Pebbly silty clay loam diamicton; unstratified; olive (oxidized) to grayish brown (unoxidized); firm to hard; compact; calcareous; massive to jointed; some cobbles, few boulders; discontinuous beds of sand, gravel, silt, or clay; overlain in places by wind-blown silt (loess) of the Peoria silt; unconformably overlies Tiskilwa Formation or older units; 5 to 35 feet thick

Pebbly loam diamicton; unstratified, reddish brown (oxidized) to dark brownish gray with distinctive reddish cast (unoxidized); firm to hard, calcareous; some cobbles; few boulders; includes discontinuous beds of stratified sand, silt, or clay; lower 5 to 30 feet commonly more silty than upper part, usually lacks reddish cast, and may contain dispersed wood fragments and gastropod shells; unconformably overlies Ashmore Tongue (sand and gravel), Morton Tongue (silt), Roxana Silt, or older deposits; 25 to 120 feet thick

Description

Shale, clay, sandstone, limestone, coal

$T

"e

"e

"e

"e

"e

"kSG 20370

Outcrop

Stratigraphic boring

Water boring

Engineering boring

Coal boring

Hand-auger boring

Labels indicate samples (S) or geophysical log (G). Numeric labels indicate the county number. Some county numbers are not shown in areas of closely spaced boreholes.Outcrop and hand-auger boring labels indicate geologist’s field number. Dot indicates boring is to bedrock.

Contact

Crest of the Eureka Moraine

Data Type

Note: The county number is 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.

! ! ! ! ! ! ! ! ! ! ! !

460

700

650

550

470

500

650

650

670

670

650

680

500

700

700

630

550

600

600

670

680

500

650

630

650

550

650

650

550

650

700

650

550

450

700

550

650

450

680

680

500

650

600

650

640

650

650

700

450

500

700

600

680

500

450

450

650

550

600

670

650

650

500

550

500

650

500

500

500

700

500

700

500

650

500

550550

650

650

500

600

650

650

650

650

680

650

460

550

500

700

450

650

550

700

650

600

700

700

700

450

650

650

450

500

500

700

650

450

650

550

670

670

650

650

600

650

650

650

650

500

650

490

480

650

550

450

500

650

500

680

680

640

690

640

670

530

500

650

650

500

680

450

470

650

500

550

650

450

550

650

680

450

600

500

500

550

600

600

650

700

9

43

21

8

5

1 6

1816

10

15

2528

13

23

14

24

16

26

33

15

21

27

7

22

35 3634

30

21

36

22

19

25

11

14

2

23

18

31

19

30

7

24

9

17

17

32

29

20

20 20

17

31

12

88

35

1211

10

6

29

13

13

26

272829 26

24

23

6

29

17

17

29

29

26

26

17

T. 30 N.

T. 29 N.

R. 3 W. R. 2 W.

T. 30 N.

T. 29 N.

T. 13 N.

R. 9 E.

R. 9 E.

T. 12 N.

T. 13 N.

T. 13 N.

T. 12 N.

R. 3

W.

R. 2

W.

R. 10 E.

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

Eu

r ek a

Mo r a i n e

"e

"k

"k

"k

"k

"k

"k

"k

"k

"e

"k

"k

"e

"e"e

"e

"k"k

"k"k"k

"k

"k

"k

"k

"e"k

"k

"k

"e

"k

"k

"e

"k

"k

"k

"e

"k

"k

"e

"e

"e

"k

"e

"k

"k

"k

"k

"k

"e

"e

"e

"k

"k

"k"k

"k"k"k

"k

"k

"k

"e

"e

"k

"k

"k

"e

#*S

$T

$0

#*S

$T

$0

$T

#*S

$0

$0$T

$T$T

$0

$0

$T #*S #*

S #*S

$T$0

$0

$0

$0

$0

$0

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e

"e "e

"e

"e

"e

"e

"e

"e

"e"e

"e"e

"e"e

"e"e

"e

"e

"e"e

"e

"e"e"e

"e

"e"e"e"e

"e"e"e

"e

"e

"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e

"e"e"e"e"e"e

"e

"e

"e

"e"e"e"e"e"e"e"e"e"e"e"e

"e

"e

"e

"e

"e

"e

"e

"e

"kS

"kS

"kS

"eS

"eS

"k

$T

"kSG

"kSG

"kSG

"e

"e

"e

"e

"k

"k

"k

"k

"k

"k

"e

"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e"e

"e

"e"e"e"e"e

"e"e"e"e"e"e"e"e"e"e"e"e

"e

"e

21010

21009

21008

20415

20230

20731

00166

00130

00040

23454

20699

20219

00167

00098

20841

20840

20839

20838

2083720836

20835

20834

20833

20832

20831

20824

20823

20822

20820

20819

20758

20349

00170

00021

20737

20230

20696

20772

20770

20765

20502

20732

20332

20507

20697

00003

00002

20223

00096

20331

00161

00160

00001

20357

20434

20659

20287

20744

20694

20337

20534

00109

20728

20363

2034500085

20746

20348

20347

20753

20372

20286

20661

20451

20407

00156

20370

00137

20432

20369

20665

20364

00022

20327

20222

20239

20793

20787

20817

20816

2050620505

20504

20503

20762

2037120394

20406

20601

539538

537

536535

534

518

580

581

517

325324

311

310

307

306

299

298

286

575

282

276

1031

577

579

578

571

572

574

570

569

568

00043

20922

20955

20951

20947

20945

20999

20885

20985

20905

20949

20998

20888

20978

2088220964

20879

20982

20983

20849

20815

20814

00037

00097

00044

20943

20934

21000

20911

20974

20977

20918

20987

20876

20826

20782

20925

20941

20971

20912

20914

20916

20906

2091920990

20989

20877

20875

20798

20846 20843

20830

20829

20828

20827

20825

20781

c(fp)

c(fp)

c(fp)

c(fp)

c(fp)

p/l-b

p/l-b

h(m)

h(m)

p/l-b

p/l-b

t

t

t

t

t

t

t

t

&cm

c(f)

h(m)

c(f)

l-b

l-b

t

t

t

t

t

t

t

t

l-b

l-b

p/l-b

l-b

h(m)

h(m)

t

t

t

t

t

t

h(m)

t

t

l-b

c(f)

h(m)

t

tt

l-b

t

t

p/l-b

c(fp)

c(fp)

l-b

t

t

l-b

t

t

py

p/l-b

t

h(m)

t

h(p)

t

p/t

p/l-b

t

p/t

t

t

p/l-b

t

&cm

p/t

t

t

c(fp)

t

l-b

l-b

l-b

t

t

l-b

p/t

t

t

t

t

t

c(fp)

c(fp)

h(m)

p/l-b

dg/h

p/l-b

t

h(p)

l-b

t

c(fp)

t

t

l-b

c(fp)

dg/h

t

p/l-b

l-b

h(p)

l-b

t

l-b l-b

h(m)

l-b

c(fp)

c(fp)

l-b

l-b

l-b

p/t

dg/h

p/t

t

t

p/l-b

t

py

t

l-b

dg/h

t

t

py

t

l-b

p/t

t

h(p)

h(p)

p/t

l-b

l-b

l-b

l-b

t

t

h(p)

p/t

h(m)

l-b

l-b

l-b

l-b

l-b

l-b

p/t

h(m)

l-b

py

p/t

t

l-b

l-b

h(p)

t

l-b

h(m)

p/t

l-b

p/t

l-b

l-b

l-b

l-b

h(p)

tt

l-b

l-b

p/l-b

t

l-b

p/l-b

p/t

l-b

l-b

l-b

l-b

l-b

l-b

l-b

l-b

t

l-b

h(m)

t

p/t

h(m)

h(m)

p/l-b

h(m)

p/t

p/t

p/l-b

h(m)

dg/hdg/h

p/t

p/t

t

dg

l-b

c(fp)

t

&cm

&cm

&cm

c(f)

&cm

&cm

h(p)

&cm

&cm

&cm

l-b

h(p)

p/l-b

h(p)

t

l-b

p/l-b

p/l-b

p/l-b

c(f)

l-b

l-b

l-bl-b

c(fp)

c(fp)

h(m)

t

l-b

l-b

l-b

l-b

l-b

l-bl-b

l-b

l-b

l-b

t

l-b

c(fp) h(p)

&cm

&cm

l-b

l-b

h(p)

l-b

p/l-b

c(fp)

l-b

p/l-b

h(p)

l-b

l-b

l-b

p/t

l-b

p/t

l-b

c(fp)c(fp)

t

c(fp)

h(p)

p/t

h(p)

l-b

h(p)

p/l-b

c(fp)

p/t

c(fp)

l-b

p/t

p/t

h(p)

c(fp)

p/t

l-b

t

p/t

h(p)

p/l-b

h(p)

p/t

h(m)

l-b

p/l-b

l-b

l-b

p/t

l-b

p/t

l-b

p/l-b

p/t

h(m)

h(m) h(m)

h(m)

p/t

l-b p/t

p/t

p/l-b

h(p)

l-b

p/t

l-b

h(m)

h(m)

c(fp)

t

l-b

h(m)

l-b

l-b

h(p)

p/t

l-b

p/t

t

p/t

p/t

l-b

l-b

l-b

l-b

c(fp)

c(fp)

l-b

p/t

p/t

l-b

l-b

h(p)

p/l-b

p/l-b

t

t

p/t

t

l-b

p/t

p/t

p/t

dg/h

l-b

&cm

t

t

p/l-b

l-b

&cm

c(fp)

&cm

c(fp)

t

l-b

l-b

TN/B

p/l-b

t

t