Illinois Map 10 2001 George H. Ryan, Governor Department of Natural Resources Brent Manning, Director ILLINOIS STATE GEOLOGICAL SURVEY William W. Shilts, Chief Geologic Road Map of Illinois: N Natural Resources Building East Dubuque Warren 615 East Peabody South Beloit Richmond Antioch 84 CHAIN- 173 Champaign Illinois, 61820-6964 APPLE RIVER Rockton 173 O-LAKES Zion ILLINOIS CANYON LAKE BEACH LE-AQUA-NA Lake Summerset Galena 78 Durand Roscoe 94 Surface Deposits and Landscapes 26 76 132 Harvard Lena 75 2 Fox Lake 251 90 14 47 83 Machesney 173 Waukegan MCHENRY DAM E 20 Stockton 70 Park ROCK CUT & LAKE DEFIANCE W Pecatonica McHenry North Chicago Woodstock David A. Grimley, Barbara J. Stiff, and Michael J. Andrew Loves Park 23 60 73 Belvidere 12 20 Marengo 176 41 Freeport 176 Mundelein Winnebago 20 Lake Forest Surface deposits compiled from Hansel and Johnson (1996), Lineback (1979), and Willman and Frye (1970) 84 59 Rockford Cherry Valley Crystal Lake 14 22 90 Huntley Lake Zurich Highland Park S Forreston MISSISSIPPI Carpentersville PALISADES 72 Byron 68 Genoa 94 Savanna Mount Carroll Lanark Arlington 26 2 Kirkland 62 Hts. 72 Hampshire WISCONSIN glacial outwash Mount Morris Mt. Prospect Evanston lake plain 39 20 Elgin Des 64 LOWDEN Skokie Driftless 47 Schaumburg Plaines Lake Michigan 52 290 WHITE CASTLE 64 41 Area PINE ROCK Oregon Sycamore 31 Milledgeville Polo FOREST 19 Michigan 19 St. Charles 20 LOWDEN-MILLER Rochelle 43 De Kalb 64 88 38 Oak Chicago 38 Elburn 59 355 Park 290 Fulton 2 Ashton 251 88 Wheaton Chicago MORRISON- Dixon Cicero ROCKWOOD 25 294 34 88 23 Morrison Sterling Downers 30 Rock Falls Waterman Hinckley Sugar Grove Naperville Grove 50 41 A 84 78 30 Aurora IOWIOWA 55 12 90 26 Amboy SHABBONA LAKE Oak A. Grimley 34 Bolingbrook 83 Lawn r PROPHETSTOWN 172 Plano 45 Erie ive Sandwich 171 88 R Prophetstown Yorkville 30 94 k LEE COUNTY 52 Port Byron c o (GREEN RIVER) R Somonauk Orland Park photo: David 6 Earlville SILVER SPRINGS 126 7 34 Tinley 71 Fast-flowing glacial meltwater streams deposited coarse sand and Walnut Park 1 photo: Leon R. Follmer W W Mendota 47 92 92 80 gravel (known as outwash) in front of glacier margins. This photo East Sheridan Downtown Chicago is built on the bed of a former glacial lake. Moline Joliet Chicago Peoria i of outwash is from the margin of the next to last glaciation near s 82 52 Heights During the latter phases of the last glaciation, Lake Michigan's Rock MolineSilvis Park c Mt. Carroll in northwestern Illinois. Deposits such as this make Colona Minooka Island 45 Forest outlet to the northeast was blocked at times by glaciers. Thus, on 78 394 o excellent aquifers for groundwater supply when found below the 6 53 Manhattan several occasions, the level of ancestral Lake Michigan near 92 Geneseo HENNEPIN 89 50 n water table. However, such aquifers are susceptible to contam- Andalusia Coal Valley CANAL Channahon Chicago was many feet higher than today. The lake basin itself s PARKWAY 251 6 i ination if not overlain by a fine-grained till or clay deposit to 92 Milan ILLINOIS & was originally formed and deepened during several glaciations by n Ladd Morris MICHIGAN CANAL impede the infiltration of surface water contaminants. 80 DES Beecher Orion 80 the scouring of ice flowing to the south. INDIANA 94 La Salle r PLAINES 52 Wyanet Princeton De Pue 6 Marseilles ive Peotone JOHNSON- 26 Peru STARVED ROCK is R GOOSE LAKE Cambridge SAUK 88 no E Illi PRAIRIE Wilmington TRAIL Spring Ottawa ILLINI Diamond river alluvium Lakewood Shores p 81 Valley MATTHIESSEN Seneca 113 57 moraine Oglesby Coal City i Granville 113 s 71 23 Braidwood Manteno 17 o Grant Park 82 Kewanee d 17 e 67 Momence in Aledo Galva 93 Gardner KANKAKEE 102 rg 29 RIVER 114 ma 34 170 55 Bradley 91 Streator Henry 18 17 # 17 Toulon Kankakee 17 Dwight 135 26 Wyoming BIG Herscher St. Anne RIVER 74 167 179 V 17 e Chebanse Toluca r Odell 78 Lacon m 94 i 180 li o 115 IROQUOIS COUNTY DELABAR MARSHALL 117 39 n Galesburg R 23 MISSOURI COUNTY Oquawka 164 iv Princeville Chillicothe e Clifton 90 r Washburn Monmouth # Pontiac pre-Illinois 164 Minonk Knoxville 88 116 St. Louis JUBILEE Rome 116 74 COLLEGE 91 WOODFORD 52 Episode 34 COUNTY 89 47 45 I photo: Leon R. Follmer l Abingdon photo: Joel M. Dexter margin l Metamora i Roanoke 24 n Postglacial river sediments range from clayey silt to sand and 8 Peoria 251 This view looking north towardsMoraine View State Park shows Elmwood Hts. Fairbury Forrest Gilman Sheldon o Germantown Hills El Paso Grindley Chenoa Watseka gravel. Faster flowing rivers deposited coarser layers of sand and Roseville Peoria 24 an end moraine (the ridge on the horizon). End moraines, such as i gravel. During glacial times, many large, fast-flowing rivers carried 116 Chatsworth this oneeast of Bloomington-Normal, mark places where an ice s Hanna 474 Onarga 49 94 City Eureka large sediment loads. Today, the sand and gravel outwash 116 55 front has remained stationary for tens to hundreds of years. In E n 96 Farmington West Washington 117 pi i deposited by these streams lies beneath more recent, finer- 67 Peoria Illinois, end moraines contain largely unsorted sediment (till), a s g East Peoria 54 Milford o r grained alluvium in many major river valleys, and below other 78 Lexington mixture of clay, silt,sand and gravel, deposited by moving or d a Dallas City Bartonville M e m glacial deposits elsewhere. These deposits are major sources of 94 97 74 Hudson ac melting ice. These ridges, which form transverse to the ice flow PEKIN Marquette kin 57 96 LAKE Hts. aw groundwater. In Illinois, about one-third of the total population and Glasford River 1 direction, outline the shape of former ice lobes. Nauvoo La Harpe Canton 24 Morton 165 90% of the rural population rely on groundwater for drinking. Bushnell 9 Pekin NAVOO 9 Mackinaw 9 9 Tremont This digital shaded relief image of Normal 115 till plain Cuba SouthPekin Illinois (from Abert, 1996) shows the unglaciated 94 RICE Hoopeston ARGYLE Macomb 9 (Wisconsin Episode) sand dunes 95 LAKE landscape of the state. Major river LAKE 100 Gibson City 9 valleys, glacial ridges, and lake Bloomington Paxton Carthage 122 # V plains can be seen. Compare with Colchester Lewiston Manito Minier er !$ m Rossville 29 ili the map of surface deposits. Arrows Hamilton MORAINE VIEW o 55 n indicate the approximate direction of L DICKSON R KENTUCKY a SAND RIDGE Le Roy i Warsaw !$ MOUNDS Delavan v M e o r glacial ice flow. in 155 Fisher e Heyworth !$ R Havana !$ 96 iv 119 e Rantoul r Atlanta 47 Astoria Farmer City Thomasboro 101 ANDERSON 97 LAKE 74 Lake of the Woods WEINBERG-KING 24 10 Mason City 54 67 45 Danville Mahomet SAND PRAIRIE- Clinton KICKAPOO SCRUB OAK Lincoln 61 10 48 !$ Rushville 74 10 # SANGANOIS 94 29 WELDON Champaign Urbana St Joseph Oakwood Catlin Tilton 100 RAILSPLITTER SPRINGS 72 Savoy 99 LOUIS H. Homer BARKHAUSEN 78 Maroa Sidney Westville Petersburg Monticello Camp Point 103 Mount 45 Philo 24 Beardstown Pulaski photo: Leon R. Follmer photo: Joel M. Dexter Tolono Quincy 24 Georgetown Mount Sterling 121 ROBERT This aerial view of a till plain of the last glaciation (Wisconsin Sand dunes in Illinois occur primarily where sandy glacial melt- 125 Williamsville Virginia 54 ALLERTON Warrensburg PARK Episode) is from Champaign County, east-central Illinois. Erosion water deposits were reworked by wind action. These dunes SITE M 123 Athens # SILOAM 124 Forsyth Bement SPRINGS of former hills by glaciers and filling in of valleys with glacial formed mainly towards the end of the last glaciation. Dune shape Ashland 29 Cerro Gordo 130 99 97 105 deposits contributed to the flatness of this landscape. Washing of and orientation indicate prevailing winds from the west and north- 104 Sherman Decatur Villa Grove sediment into former lakes and low areas during permafrost west, just as the Midwest currently experiences during the late fall, Riverton Harristown 172 Meredosia 125 105 conditions also contributed to the flatness. The landscape has winter, and early spring. This photo is from a dune field in north- Payson 72 104 Long Creek Atwood Tuscola Chrisman 123 iver remained virtually unchanged because, from a geological eastern Illinois near Kankakee; however, many dunes also occur R 36 96 on 36 standpoint, there has been little time for erosion (only 18,000 in the western part of the state such as at Sand Ridge State Park. Springfield am LINCOLN TRAIL SPITLER Rochester ng HOMESTEAD 48 WOODS 100 Jacksonville Sa Mount Zion 49 years since glaciation here). Agricultural fields in these areas generally require irrigation 107 36 Lovington Arthur WALNUT 106 Griggsville 72 because the sandy soils are porous and thus do not retain water Barry Blue Mound 133 POINT Macon Arcola well. 72 South Jacksonville 121 ridged drift 104 SANGCHRIS Chatham LAKE Stonington Bethany Winchester 29 32 133 Paris dissected till plain # 106 Moweaqua Sullivan (pre-Illinois Episode) Pittsfield Waverly Pawnee Kinkaid 128 Auburn 104 267 45 130 16 67 Divernon 1 Taylorville 100 EAGLE 106 Assumption CREEK WOLF Mattoon 54 55 CREEK Roodhouse Virden 48 96 Pleasant Hill 16 111 29 Charleston White Hall Girard Windsor Morrisonville 16 FOX RIDGE 4 Shelbyville Marshall 40 A timetable of glacial and interglacial episodes Pana during the last 1 million years in Illinois Greenfield 4124)2 HIDDEN Neoga LINCOLN Martinsville (modified from Killey, 1998). SPRINGS 121 TRAIL 108 Casey 96 Carlinville Nokomis Toledo Carrollton 70 108 32 Greenup BEAVER DAM 127 16 100 photo: Leon R.