Major Aquifers in Glacial Drift Near Mattoon, Illinois, by John W

V. MAN f.l '11 Of.lf.AI MJH'/I f 3 3051 00004 0489 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/shortfmpersongeo179fost j. 179 STATE OF ILLINOIS ADLAI E. STEVENSON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION C. HOBART ENGLE, Director DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON, Chief CIRCULAR NO. 179 SHORT PAPERS ON GEOLOGIC SUBJECTS Major Aquifers in Glacial Drift near Mattoon, Illinois By John W. Foster Notes on the Illinois "Lafayette" Gravel By J. E. Lamar and R. R. Reynolds Cambrian and Lower Ordovician Exposures in Northern Illinois By H. B. Willman and J. S. Templeton An Occurrence of Barite in the LaSalle Limestone of Illinois By Raymond S. Shrode Revision of Croixan Dikelocephalidae By Gilbert O. Raasch REPRINTED FROM THE TRANSACTIONS OF THE ILLINOIS STATE ACADEMY OF SCIENCE VOL. 44, pp. S5-128, 137-151, 1951- PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 1952 JUJNQSS GEOLOGICAL SURVEY LIBRARY JUL 16 1952 Illinois Academy of Science Transactions, Vol. 44, 1951 GEOLOGY MAJOR AQUIFERS IN GLACIAL DRIFT NEAR MATTOON, ILLINOIS* JOHN W. FOSTER State Geological Survey, Urbana Subsurface Pleistocene studies location of the areas most favorable near Mattoon recently conducted by for well field construction. The pres- the Illinois State Geological Survey ent investigation, largely a subsur- have revealed the probable origin face study by the records of 114 drift and nature of occurrence of two borings, has been designed toward gravel aquifers of major importance. not only descriptive geology but an The report describes a veneer of insight into the physical develop- sand and gravel which rests on the ment of the Mattoon aquifers. It is Sangamon interglacial surface over hoped that this insight will lead to- a wide area north of the Shelbyville ward a better understanding of the moraine which here marks the maxi- groundwater available to Mattoon, mum stage of Wisconsin glaciation. its industries and hinterland farms, A second, more restricted but more and lead also toward the discovery favorable aquifer of Shelbyville age of other still unknown aquifer de- lies immediately south of the Shelby- posits of similar rank lying in areas ville terminus and extends from the of similar Pleistocene history. ground surface to the top of Illi- General setting.—The one hun- noian drift. The relationships of dred and ninety-two square miles these gravel aquifers to the Cerro of the Mattoon investigation lie en- Gordo and Shelbyville moraines, to tirely in southwestern Coles county the undulations of the Sangamon and include Townships 12 and 13 surface, and to the topography of north, Ranges 7 and 8 east, and the the top of the bedrock are described. north four section tiers of Township The investigation is expected to lead 11 north, Range 7 and 8 east. The to the discovery of unknown aquifer terrain is largely rolling to nearly deposits of similar genesis in areas level upland prairie, shedding drain- of similar geologic conditions. age west into the Kaskaskia, south Introduction. — Geological and into the Little Wabash, and east into geophysical studies of the gravel the Embarrass systems. Relief is aquifers near Mattoon have been only 165 feet, with elevations rang- conducted by the State Geological ing from about 620 feet on the Kas- Survey at intermittent periods for kaskia River in the northwest area many years. The older surveys have and the Little Wabash River in the been directed principally toward the southwest area to about 785 feet on the highest crest of the Shelbyville moraine (fig. 2) near the southwest Illinois Academy of Science Transactions corner of T.12 N., R.8 B. Mattoon, with a population estimated at more than 18,000, lies on the gentle north or backslope of the Shelbyville moraine in the south-central area. As in most of east-central Illinois, the glacial drift near Mattoon rests on the shales, thin limestones, sand- stones, and coals of the Pennsylvan- ian system. Bedrock here is exposed at very restricted locations along the Kaskaskia A^alley north of the Cerro Gordo moraine (figs. 2 and 3). Everywhere else drift, with estimated thicknesses up to approximately 220 feet in southwestern T.12 N., R. 7 E., buries the bedrock surface and completely obscures its topography. Drift of Illinoian age is capped with younger Wisconsin deposits associated with the Shelby- ville and Cerro Gordo ice lobes (Leighton, Ekblaw, Horberg, 1948, p. 22) of Tazewell age. Each of these drift mantles shows surface expres- sion, the Illinoian as a nearly level till plain beyond the influence of Fig. 1.—Index map showing location Wisconsin ice, the Shelbyville as a of the area of investigation near Mattoon, prominent moraine, and the Cerro Illinois. Gordo as a more gentle moraine and till plain in the far north portion appear to trend westward and north- of the Mattoon area. westward as part of the buried Mid- dletown valley which in turn is in The bedrock surface.—The buried confluence bedrock surface of the Mattoon area with the ancient course ;' of the Mississippi River in eastern is principally interfluve between the pre-glacial Embarrass (Horberg, Mason County. Although Illinoian drift to a great degree obscured the 1950, p. 84) and Middletown (Hor- subdued topography of the top of' berg, 1950, p. 73) drainage systems. the bedrock, the of the The shallow sags in the bedrock southernmost west-trending bedrock valleys ap- topography in the northeast portion of the area were apparently courses pears to have influenced the building of a Wisconsin gravel aquifer, and 1 tributary to the great Embarrass influences the hydrologie bedrock valley which trends south- probably characteristics of that aquifer. erly in the eastern part of Coles County. The more prominent bed- Illinoian drift.—For the most parf rock valleys of the Mattoon area the bedrock near Mattoon is mantled Aquifers in Glacial Drift CONTOUR INTERVAL 50 FEET MILES [9 | 3 ? Fig. 2.—Surface contour and moraine configuration map. Illinois Academy of Science Transactions CONTOUR INTERVAL 25 FEET ^-60<\ APPROXIMATE ELEVATION OF TOP OF BEDROCK A = BEDROCK EXPOSURE IOI23 MILES Fig. 3.—Buried bedrock surface contour map. Aquifers in Glacial Drift with Illinoian drift. Two exceptions this fact by no means precludes such are noted: (1) Reliable samples from a history. a 1944 Mattoon City test hole lo- Aquifer material in Illinoian cated NE. SE. NE. sec. 18, T.ll N., drift, though very uncommon near R. 7 E., indicate that the basal ma- Mattoon, may be extremely impor- terial is a fine to coarse silty sand tant in its influence on the hydrology with an abundance of humus and of Wisconsin gravels immediately most likely represents a Yarmouth south of the Shelbyville moraine. In interglacial alluvial deposit. No con- sec. 18, T.ll N., R.7 E., pre-Wiscon- vincing evidence of Kansan drift sin sand deposits are as thick as 45 has been noted in this subsurface feet and occupy there a well- investigation. (2) Three borings in developed valley of the bedrock sur- T.ll N., R. 7 E., penetrated to the face, drift boring number 4, fig. 4. bedrock without apparently cutting The nature of this pre-Wisconsin pre-Wisconsin material. These sug- sand is unknown, but the deposit is gest that Sangamon erosion denuded very likely restricted to the bedrock the bedrock at numerous though valley in which it lies, and probably probably restricted locations princi- trends westward in conformity with pally along Sangamon drainage sys- the valley configuration. Samples tems and in localities where Illinoian from boring number 4 suggest that drift was originally thin. Inasmuch this sand is silty to very silty and as the top of Illinoian drift appears may not in itself be an important to have been a gently undulating direct source of groundwater. plain, at an average elevation of Sangamon soil.—Well drillers in about 625 feet, the greater Illinoian the Mattoon area are familiar with drift thicknesses occur generally the "peat" which rests largely on over the depressions of the bedrock Illinoian till. It is this remarkably surface. The greatest Illinoian drift preserved soil section that has pro- thickness in the Mattoon area is esti- vided an excellent horizon marker mated to be about 90 feet where a here. low bedrock surface is overlain by a The excellence of the Sangamon relatively high Sangamon surface in interglacial soil development as a sec. 19, T.12 N., R.8 E. marker near Mattoon has enabled Illinoian drift over wide areas the use of driller's logs where they here is exclusively a grey or grey- might otherwise be of little value green calcareous clay till which lacks in geological Pleistocene interpreta- the sandy character typical of Illi- tion. Unusual preservation of Sanga- noian drift in most of Champaign mon loam here through the over- County. The upper 5 to 10 feet of running of the later Wisconsin Illinoian till shows clearly by repre- glacier is probably due to the equally sentative samples the weathering unusual nature of the advance of during the Sangamon interglacial the Shelbyville ice. period. The general textural homo- Shelbyville ice progression and geneity of the Illinoian drift lends the spreading of gravel veneer.—The ' no support to the possibility of mul- progression of Shelbyville ice into 1 tiple Illinoian glaciation, although the Mattoon area early in Tazewell Illinois Academy of Science Transactions 5 • V- ~v= Aquifers in Glacial Drift 91 time, with a southwesterly lobate first in the sag in the Illinoian drift axis, began the key period of aquifer surface (which is apparently the re- building.

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