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 http://archive.org/details/conservationscho1955illi 
 
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 .1 
 
 State of Illinois, Department 
 
 of Registration and Education 
 
 STATE GEOLOGICAL SURVEY, URBANA 
 
 JOHN C. FRYE, Chief 
 
 MINERAL RESOURCE 
 RECORDS DiVIS'IOiN 
 
 ^//0 3 S3 3 
 
 GEOLOGICAL 
 
 Conservation School 
 
 GUIDE LEAFLET 
 
 Fairgrounds, Springfield, Illinois 
 
 SPRINGFIED AREA SANGAMON CO 
 
 SPRINGFIELD QUADRANGLE 
 
 June 29, 1955 
 
 Leader 
 
 GEORGE M. WILSON 
 
 ILLINOIS STATE GEOLOGICAL SURVEY, URBANA 
 
 4^ 
 
FIELD TRIP FOR CONSERVATION SCHOOL 
 
 ITINERARY 
 
 Suggestion: Ask one passenger in car to 
 read itinerary aloud as trip proceeds. 
 
 Mileage 
 
 0.0 0.0 Assemble at Fairgrounds, south gate, cars headed east. 
 
 0.2 0,2 Stop . Intersection of Routes 5h and City -U.S. 66. Turn left (north) 
 on Route 66. 
 
 3.0 3.2 Sangamon River. Note the sandstone on left side of north bank. The 
 
 sandstone is the Trivoli sandstone of Pennsylvanian or Coal Measures 
 age. 
 
 0.2 3 -U CAUTION. Turn left, then right on Illinois Route 12iu 
 
 1.6 5.0 Turn left. 
 
 0.3 5.3 Turn right. We are crossing the Jacksonville till plain, deposited 
 during one of the substages of the Illinoian glaciation. Note how 
 flat the land is. 
 
 5.7 11.0 Turn right. 
 
 2.0 13.0 You are now at the outer margin of the Buffalo Hart Moraine, here 
 characterized by low hills. 
 
 1.6 lit. 6 STOP 1 . A crevasse deposit on the Buffalo Hart moraine . 
 
 Tens and hundreds of thousands of years ago most of Illinois (with 
 most of northern North America) was covered by huge ice-sheets or 
 glaciers. The glaciers expanded from centers in what is now eastern 
 Canada. They developed when, for some reason not yet known, the 
 mean annual temperatures were somewhat lower than now, so that not 
 all of the snow that fell during the winters was melted during the 
 summers. The snow residues accumulated year after year until they 
 formed a sheet of ice so thick that its own weight caused the lower- 
 most part to flow outward, carrying with it the soil and rocks on 
 which it rested and over which it moved. The process continued 
 until the glacier extended into our country as far south as Missouri 
 and Ohio rivers. 
 
 Milder temperatures halted the glacier. For a while the ice melted 
 as fast as it moved forward so that its margin remained stationary. 
 Later the ice melted faster than it moved forward and the ice front 
 gradually melted back until the glacier disappeared. 
 
 As the glacier melted, it released its load of soil and rocks, or 
 drift , which it had picked up as it advanced. Some of the material 
 was deposited in place as the ice melted. Such material is a 
 thorough mixture of all kinds and sizes of rocks and is known as till . 
 Some of the glacial drift was washed out with the melt-waters. The 
 
-2- 
 
 coarsest out wash material was deposited nearest the ice-front and 
 increasingly finer material was deposited farther away. The finest 
 clay may have been carried all the way to the ocean. Where the 
 outwash material was spread widely in front of the glacier it forms 
 an outwash-plain; where it was restricted to the river valleys it 
 forms valley -trains * 
 
 At times, especially in the winters, the outwash plains and valley- 
 trains were exposed as the melt-waters subsided. The wind picked 
 up silt and fine sand from their surfaces, blew it across the coun- 
 try, and dropped it to form deposits of what is known as loess . 
 Glacial loess mantles most of Illinois. Near the large river valleys 
 loess may be as much as 60 to 80 feet thick. Far from the valleys 
 it may be measured only in inches, if it can be identified at all. 
 
 We know there were four major periods of glaciation during the 
 Pleistocene or Great Ice Age (see accompanying table), and that 
 between each pair of glaciers there was a long interglacial period 
 in which conditions were about as they are today. During each 
 major glaciation the ice advanced and retreated a number of times, 
 particularly during the last or Wisconsin glacial stage. 
 
 We know the Springfield region, like the rest of southern and western 
 Illinois, was invaded by glaciers during the Kansan and niinoian 
 (second and third) glacial stages, for we find glacial drift of 
 these ages. Probably the region was invaded by the Nebraskan or 
 oldest glacier, although no Nebraskan materials have been identified. 
 The Wisconsin (fourth) glacial stage is represented by loess, out- 
 wash, and wind-blown sand. 
 
 The position of the ice-front at each advance of the glacier is 
 usually marked by a ridge of till or moraine . The moraine represents 
 accumulation of drift at the ice-margin while advance and melting 
 of the ice were in balance and when more and more material was being 
 brought to the edge by the advancing ice. When melting exceeded 
 advance, so that the ice-front retreated, the resulting drift de- 
 posits form a drift -plain or till -pi a in , whose surface may be almost 
 level or somewhat billowy. 
 
 This stop is on top of a crevasse deposit along the Buffalo Hart 
 moraine. The Buffalo Hart moraine is a low broad moraine with 
 numerous high hills and ridges. The moraine marks the limit of the 
 glacier during the third or youngest substage of the Illinoian stage. 
 The hills and ridges mark the positions of crevasses in the glacier, 
 in which material accumulated in excess over what was borne in the 
 glacier itself. Outside the moraine, to the southwest, is the drift- 
 plain of the Jacksonville substage, which is almost flat. Although 
 the Buffalo Hart drift-plain to the northeast is also relatively 
 flat, it is not as flat as the Jacksonville drift-plain but is 
 characterized by low swells and swales, 5 to 10 feet in relief. 
 
 0.7 15.3 Stop . Route 66. Turn right on 66. 
 
 2.0 17.3 Caution . Town of Williamsville, RR crossing. Leave Route 66 and 
 continue straight south. 
 
-3- 
 
 0.8 18.1 Outer margin of the Buffalo Hart moraine. To the south is the 
 Jacksonville till -plain. 
 
 5.6 23.7 Stop . U.S. Route 5k. Turn right on 5k. 
 
 0.6 2b. 3 STOP 2 . Sand Dunes . 
 
 During Wisconsin time the Sangamon River valley carried great quan- 
 tities of glacial melt-water which dumped outwash gravel to form a 
 valley-train. Later the river cut a new channel into the valley- 
 train. The top level of the valley -train is now marked by terraces 
 along the sides of the valley. Some of the finer sands were blown 
 from the valley and were deposited on the uplands along the valley 
 where they accumulated as sand dunes. The dunes are now covered 
 with grass. 
 
 2.0 26.3 Turn right (south) from Route 5k onto gravel road. 
 
 0.8 27.1 Stop. Turn left (east). 
 
 l.k 28,5 Stop . Intersection with U.S. Route 36. Straight ahead, then left 
 (north) on Route 36, across the valley of Sangamon River. Note the 
 numerous old channels in the river bottom. The present river mean- 
 ders over a wide flat but the valley-walls are in bedrock. 
 
 1.3 29.8 Note the sand dunes east of Riverton. 
 
 1.3 30.8 STOP 3 « Soil profile at underpass under Illinois Terminal Railroad . 
 
 The uppermost glacial deposits in the Springfield region are loesses 
 of Wisconsin age, three in number. The latest and topmost was 
 deposited principally during the Tazewell substage, and on it has 
 developed the present surficial soil or weathering profile. It is 
 generally buff in color. 
 
 The second loess was deposited during the Iowan substage and is 
 generally gray in color. The time interval between the deposition 
 of the Iowan loess and later deposits was too brief for a weathering 
 profile to be developed, but where the Iowan loess is thin it may 
 be noncalcareous, presumably because it was leached as rapidly as 
 it was deposited. 
 
 In much of Illinois the Iowan and later Wisconsin loesses cannot 
 be readily differentiated, and they are usually designated together 
 as the Peorian loess. 
 
 The first and oldest Wisconsin loess is the Farmdale . It is typical- 
 ly chocolate brown in color. It is also generally leached, presum- 
 ably because it was deposited so slowly that it was leached as it 
 was deposited. However, the time interval between the deposition 
 of the Farmdale and Iowan loesses was sufficient that some humus 
 and locally peaty or even woody material accumulated at the top of 
 the Farmdale loess. Where the Farmdale loess is only a few inches 
 thick and lies on well-developed Sangamon soil, the two cannot be 
 readily differentiated. 
 
-h- 
 
 Like many other things, rocks and minerals suffer changes when they 
 are exposed to the weather. Although these changes are relatively 
 slow, they become evident in earth deposits that are not disturbed 
 over long periods of time and develop what is known as a weathering 
 or soil profile in the surficial part of such deposits. 
 
 Following the practice established about 30 years ago by the Russian 
 Glinka, soil scientists usually consider that the soil or weathering 
 profile consists of 3 zones, designated A, B, and C from top down. 
 The A zone is the "soil" zone, which is normally black or gray in 
 color. The B zone is the "subsoil" zone, and the C zone is the 
 unaltered parent material. 
 
 The zonal effect results from the fact that the four principal 
 processes which cause soil weathering all progress with the down- 
 ward movement of groundwater but at different rates. These pro- 
 cesses, listed according to their rate of progress and beginning 
 with the most rapid, are: (1) oxidation, (2) leaching of carbonates, 
 (3) decomposition of more resistant minerals, and (h) accumulation 
 of humus. 
 
 Consequently, in the A zone, in which humus from decaying plants 
 has accumulated, the rock minerals are oxidized, leached, and de- 
 composed. In the upper part of the B zone they are oxidized and 
 leached, and in the lower part of the B zone they are only oxidized. 
 The oxidation zone is shown by the reddish or yellowish color result- 
 ing from the oxidation of iron minerals. The leached zone is deter- 
 mined by the absence of carbonates, as revealed by tests with a 
 solution of hydrochloric acid. 
 
 The typical soil profile is developed on deposits of Tazewell age 
 at this stop. The excavation for the underpass has exposed deposits 
 of the Wisconsin stage of glaciation as follows: 
 
 Thickness 
 Ft. In. 
 Recent 
 
 Soil, gray, carbonaceous (loess) 1 6 
 
 Peorian 
 
 Loess, tan to gray, weathered, noncalcareous, with 
 
 loess kindchen (concretions) 3 
 
 (Tazewell) 
 
 Lake silt, light gray, fine-grained, discontinuous, 
 
 lenticular 0-18 
 
 Sand, medium- to fine-grained, reddish (dune sand) . 3 
 Sand, light gray, fine-grained, water-bearing, 
 
 unweathered 1 
 
 Peat, earthy, black, moist 1 6 
 
 Sand, light gray, fine-grained, unweathered, 
 
 water-bearing 1 
 
 Covered interval to base of cut 
 
 1.2 32.0 Turn right (west). Sand dunes are evident on the upland here. To 
 the southwest is the Sangamon valley in which terrace deposits make 
 the "second bottom." 
 
t5- 
 
 Almost immediately after turning the corner the road drops down to 
 the terrace level. This is one of the remnants of the great deposits 
 of sand and gravel outwash dumped into Sangamon valley during the 
 Wisconsin stage of glaciation. 
 
 0.7 32.7 Turn left into parking area at gravel pit. 
 
 STOP k . Gravel pit . 
 
 The company is dredging gravel from the valley -train outwash of 
 Tazewell age. The sand and gravel is as much as 65 feet thick. 
 The gravel is washed, screened, sized, and hauled to a sand and gravel 
 yard nearer Springfield, which we will pass later. 
 
 Sand and gravel is an important mineral resource in construction work 
 of all sorts. Too heavy to bear the cost of expensive transportation, 
 sand and gravel is sought near building sites. 
 
 Leave parking area and turn left (west) on gravel road. 
 
 As you cross the bridge over Sangamon River, note the shale above the 
 No. 8 coal. This coal, seldom more than 18 inches thick, was mined 
 in the Springfield area many years ago. 
 
 1.3 3^.0 Stop. U.S. Route 36. Turn left onto Route 36. Watch on the left 
 ( east ) for the sand and gravel yard. 
 
 3.0 37.0 Stop . U.S. Route 66. Turn left onto Route 66. 
 
 1.8 38.8 Caution . Turn right (west) on road to pit of the Poston Brick Company. 
 
 0.2 39.0 STOP 5 . Shale, pit . 
 
 The section exposed here is as follows: 
 
 Thickness 
 Ft. In. 
 Peorian 
 
 Loess, gray, weathered, carbonaceous, noncalcareous 7 
 
 Loess, tan-buff, weathered, noncalcareous 1 
 
 Loess, buff -brown, with ironstain, grades down into h 9 
 Loess, gray, very fine-grained, irregular brown- 
 stained areas 1 h 
 
 Farmdale 
 
 Loess, pink to tan, denser and harder than above, 
 
 noncalcareous h 3 
 
 Loess, mottled gray and brown, noncalcareous ... k 
 Sangamon 
 
 Soil, gray, fine, carbonaceous 0-2 
 
 Jacksonville drift 
 
 Till, weathered, oxidized, brown to tan, with iron- 
 stains; small quartz pebbles in till portions, 
 
 noncalcareous h 
 
 Till, brownish-gray, with many quartz pebbles . . . h 
 Till, gray, faintly calcareous, with limestone 
 
 pebbles 1 3 
 
-6- 
 
 Thickness 
 Ft, In. 
 Pennsylvanian 
 
 Shale, medium gray, medium-grained, micaceous, car- 
 bonaceous, well laminated, heavy bedded in part 25 
 
 Pleistocene deposits 
 
 Below the Peorian loess, which was discussed at Stop 3> there are 
 exposed older deposits of Pleistocene age. The youngest is the 
 Farmdale loess, which belongs to the oldest substage of Wisconsin 
 glaciation. 
 
 Below the Farmdale deposits there is about 6 feet of niinoian till 
 greatly weathered during the succeeding Sangamon interglacial stage. 
 Geologic studies of the soil profiles developed on the older drifts 
 - Illinoian, Kansan, and Nebraskan - reveal that they can be divided 
 into 5 zones, or horizons, instead of the 3 first recognized by 
 Glinka in the soil profile developed on the Wisconsin drift. In order 
 to avoid confusion they have been designated by numbers instead of 
 by letters. 
 
 Horizon 1 is the old "soil" or humus zone. Horizon 2 is a dense 
 layer, very gummy and plastic when wet, very hard when dry. Horizon 
 3 is the leached and oxidized zone, and Horizon k is the oxidized 
 but calcareous zone. Horizon 5 is the unaltered parent material. 
 
 The development of 5 instead of 3 recognizable zones in the old drifts 
 results from the fact that they are much more weathered. The total 
 thickness of the weathering on the old drifts is much greater than on 
 the Wisconsin drift, even where they are overlain by younger drifts. 
 Oxidation, leaching, and decomposition of minerals have all progressed 
 deeper. In addition, another process, the downward transfer of clay 
 minerals derived from the decomposition of other minerals originally 
 in the drifts, has not only left Horizon 1 more silty than it was 
 originally but has made Horizon 2 much denser and more plastic than 
 it was originally. This dense, plastic "gumbo" horizon is so little 
 developed on Wisconsin drift that it is not differentiated. 
 
 Pennsylvanian formations 
 
 The formations of the Pennsylvanian (Coal Measures) system occur in 
 repeated sequences or cycles, called cyclothe ms . Each cyclothem seems 
 to record a recession and a readvance of the seas in which the sedi- 
 ments were deposited. The accompanying diagram shows the succession 
 of beds in an ideal cyclothem. Rarely are all of the beds found in 
 any one cyclothem. More than 50 cyclothems have been identified in 
 Illinois. 
 
 The Trivoli cyclothem contains No. 8 coal; the coal was mined locally 
 at an early date near Springfield. 
 
 The shale overlying the No. 8 coal is being mined here for use in 
 the manufacture of light-weight aggregate and brick. In some places 
 in Illinois loess is also used to make brick. 
 
-7- 
 
 The St. David cyclothem contains coal No. 5, also called the Spring- 
 field coal, which ranges in thickness from hz to 6 feet and occurs 
 at depths from 130 to nearly 300 feet. Much of coal No. $ has been 
 mined from below Springfield and its suburbs, for the area is one of 
 the most intensively mined areas in the State. In Sangamon County 
 more than 65 square miles of No. 3> coal have been mined, but an even 
 larger area remains unmined. 
 
 In the southern part of Sangamon County No. 6 coal has been mined and 
 is currently mined at the Peabody No. 10 mine. More than 18 square 
 miles of No, 6 coal has been removed. 
 
 Coal remains a resource of great importance to the Illinois economy. 
 
 M ,M,K 
 
 ftTK 
 
 Thanks for coming I 
 
CLASSIFICATION OF PLEISTOCENE GLACIATION 
 (After M. M. Leighton and H. B. Willman, 1950) 
 
 STAGES 
 
 SUB -STAGES 
 
 NATURE OF DEPOSITS 
 
 Recent 
 
 
 Soil (infantile to youthful profile of 
 weathering), lake and river deposits, 
 dunes , peat 
 
 
 Wisconsin 
 (4th glacial) 
 
 Mankato 
 
 1 
 
 Cary 
 Tazewell 
 
 Iowan 
 Farmdale 
 
 i No recognized deposits in Spring.-' )" 
 1 field area ) 
 
 ) ) 
 
 )Peorian 
 Outwash sand and gravel, loess, ..) ' : 
 
 duhfes, lake deposits ) 
 Loess ) 
 Loess 
 
 
 Sangamon 
 (3rd interglacial) 
 
 
 Soil (mature profile of weathering) , 
 alluvium, peat 
 
 Illinoian 
 (3rd glacial) 
 
 Buffalo Hart 
 
 Jacksonville 
 
 Pays on 
 (terminal) 
 
 Love land 
 (Pro. -111.) 
 
 Drift 
 Drift 
 Drift 
 
 Loess (in advance of glaciation) 
 
 
 Yarmouth 
 (2nd interglacial) 
 
 
 Soil (mature profile of weathering) , 
 alluvium, peat 
 
 Kansan 
 (2nd glacial) 
 
 
 Drift 
 Loess 
 
 
 Aftonian 
 (1st interglacial) 
 
 
 Soil (mature profile of weathering), 
 alluvium, peat 
 
 Nebraskan 
 (1st glacial) 
 
 .... ... 
 
 Drift 
 
GENERALIZED GEOLOGIC COLUMN 
 FOR THE SPRINGFIELD AREA 
 
 ERAS 
 
 PERIODS 
 
 EPOCHS 
 
 FORMATIONS 
 
 Cenozoic 
 
 Quaternary 
 Tertiary 
 
 Pleistocene 
 
 Pliocene 
 
 Miocene 
 
 Oligocene 
 
 Eocene 
 
 Paleocene 
 
 (See detailed classification of 
 Pleistocene) 
 
 ) 
 
 ) Present in extreme 
 ) southern Illinois 
 ) only 
 ) 
 
 
 Cretaceous 
 
 
 Present in extreme southern Illinois 
 only 
 
 Mesozoic 
 
 Jurassic 
 
 
 Not present in Illinois 
 
 
 Triassic 
 
 
 Not present in Illinois 
 
 
 Permian 
 
 
 Not present in Illinois 
 
 
 Pennsylvanian 
 
 
 Sandstone, siltstone, limestone, 
 shale, clay, coal 
 
 
 Mississippian 
 
 Chester 
 Iowa 
 
 Not present in Springfield area 
 
 St. Louis, Salem, Warsaw-Keokuk, 
 Burlington, and Kinder hook 
 
 
 Devonian 
 
 
 Limestone and sandstone 
 
 
 Silurian 
 
 
 Limestone and dolomite. Oil produc- 
 tion in Mt. Auburn area, Sangamon Co. 
 
 
 Ordovician 
 
 
 Shale, limestone, and sandstone 
 
 
 Cambrian 
 
 
 Dolomite and sandstone 
 
 Proterozoic 
 Archeozoic 
 
 Refe: 
 
 rred to as "Pre- 
 
 -Cambrian" time 
 
i ^- " '. — •■■ - — Shale, gray, sandy. 
 
 Shale, gray, sandy at top; contains marine fossils and ironstone 
 concretions especially in lower part. 
 
 Limestone ; contains marine fossils. 
 
 Shale, black, hard, laminated ; contains large spheroidal concre- 
 tions ("Niggerheads") and marine fossils. 
 Limestone ; contains marine fossils. 
 
 Shale, gray; pvritic nodules and ironstone concretions common at 
 base; plant fossils locally common at base; marine fossils rare. 
 
 Coal ; locally contains clay or shale partings. 
 
 Underclay, mostly medium to light gray except dark gray at top; 
 
 upper part noncalcareous, lower part calcareous. 
 Limestone, argillaceous; occurs in nodules or discontinuous beds; 
 usually nonfossiliferous. 
 
 Sandstone, fine-grained, micaceous, and siltstone, argillaceous; 
 variable from massive to thin-bedded ; usually with an uneven 
 lower surface. 
 
 AN IDEALLY COMPLETE CYCLOTHEM 
 
 (Reprinted from Fig. 42, Bulletin No. 66, Geology and Mineral Resources of the Marseilles, 
 Ottawa, and Streator Quadrangles, by H. B. Willman and J. Norman Payne) 
 
TILL PLAINS SECTION, 
 
 GREAT LAKE 
 
 SECTION 
 
 CENTRAL 
 LOWLAND 
 PROVINCE 
 
 ENTRAL 
 
 LOWLAND 
 
 PROVINCE 
 
 ^INTERIOR 
 LOW 
 
 PLATEAUS 
 PROVINCE 
 
 ILLINOIS STATE GEOLOGICAL SURVEY 
 
 COASTAL PLAIN 
 PROVINCE 
 
 PHYSIOGRAPHIC DIVISIONS OF ILLINOIS 
 
 (Reprinted from Report of Investigations No. 129, Physiographic Divisions of Illinois, 
 by M. M. Leighton, George E. Ekblaw, and Leland Horberg) 
 
 ' (71328) 
 
ILLINOIS STATC GEOLOGICAL SURVEY 
 
 GLACIAL GEOLOGY IN NORTHEASTERN ILLINOIS 
 
 Compiled by George E. Ekblaw from data furnished by the Survey 
 
 January 1, 1942 
 
 (71330— 5M— 5-53)