Surficial Geology Map for the Freeport East 7.5 Minute Quadrangle, Stephenson County, Illinois
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Surficial Geology Map for the Freeport East 7.5 Minute Quadrangle, Stephenson County, Illinois Surficial Geology Map for the Freeport East 2013 7.5 Minute Quadrangle, Stephenson County, Illinois Cheyenne Morgan, Eric Peterson, Robert Nelson, 89 94 Qg 0 Qpr 0 0 Og Qg 0 0 94 9 Kathryn Schroeder, Dave Malone 8 7 Og 0 Qg Og 9 0 00 Qpr 4 Qg Qg Qpr Department of Geology-Geography, Illinois State University 8 Qpr 0 5 Qc Qpr 9 93 2013 940 0 92 Qg 0 Qg Qg 0 Quaternary System Qpr 2 9 950 9 2 Qg 890 0 Qpr89 0 0 Og 4 94 Og Qpr 9 0 8 Qg 3 9 0 Og Floodplain 4 910 0 95Og0 930 Qg 9 Qpr 2 950 0 Alluvium Qg 9 0 96 4 1 9 Qpr Qpr Not much is known of the large-scale geology of Stephenson County. Though numerous wells 0 0 9 30 Qg 950 9 9 have been drilled within the Freeport East Quadrangle, the geologic data provided from these wells 6 20 930 Og 0 Floodplain have not been collected, organized, and analyzed. The principal focus of this project will be to Og Qg Qg 9 Og 0 create a surficial geologic map of the Quaternary and overlying units within the region. The 2 92 930 0 8 Alluvium 8 80 surficial geology map is needed to understand the local geology and will assist in future geologic 8 Qpr Qpr Qg 0 Og 0 91 and hydrogeologic investigations within the Freeport area. Due to the composition of the partially 0 Qc Qpr 7 8 9 6 3 8 0 0 Cahokia Alluvium buried bedrock valley and the current downcutting of the Pecatonica into the surrounding geology 91 0 0 92 0 3 Qpr there is a need to assess both shallow and deep aquifer sensitivity within the region. There is also 8 91 810 Modern creek valley and river channel 0 0 0 Qpr 88 potential for aggregate resource development as there are currently eighteen small quarries within Qg Og 3 deposit that is primarily composed of stratified Og Qpr 9 91 Qpr 8 Qc silt, clay, and sand. 0 30 Qg the region. Qpr 8 4 20 The Freeport East 7.5’ Quadrangle, 1:24,000 scale, is located in the northwestern corner of Illinois 0 89 9 8 8 Qpr 0 00 8 0 Grayslake Peat within Stephenson County. Stephenson County is bounded to the north by the Wisconsin border, to 8 Qpr 0 9 2 Qg 0 Qg 8 Qpr the east by Winnebago County, and to the west by Jo Daviess County. The quadrangle is located in 8 0 0 0 2 9 900 70 8 8 0 8 8 90 Organic silt and clay. Intertongues with the area between 89°37’30W and 89°30’W longitude and 42°22’30N and 42°15’N latitude. The 8 900 8 8 8 8 Cahokia Formation. 8 50 60 0 Qg Qgp 0 Qg Freeport East Quadrangle includes the eastern portion of Freeport, Illinois, which serves as the 0 81 largest municipality in the county with a population of 24,161 individuals. The drainages in the 8 10 Qpr Qpr 0 quadrangle include the Pecatonica River, Crane Grove Creek, Silver Creek, Winneshiek Creek, and Og 8 Henry Formation 8 0 Qg Yellow Creek. The area can be accessed by US 20, Illinois Route 75, and Illinois Route 26 and 0 Qg dozens of country roads and city streets. Og 9 Stratified sands and gravels of moderate to 890 Qg 870 considerable thickness. A glaciofluvial deposit that is channelized along stream and river 780 89 Qh Much of the glacial deposits in the Freeport East Quadrangle were deposited during the late 0 valleys during glacial retreat. 89 8 0 5 0 0 0 6 7 Pleistocene (Doyle, 1965). Nearly all the valleys within the area were filled with glacial drift as the 8 8 8 L 6 Qpr 40 I 0 glacier advanced from the east on a S75°W trend. Stream diversion channels, thinness of drift 0 6 Qpr Peoria Roxana Silt 8 Qpr Peoria Roxanna Silts throughout the area, the absence of end-moraines, and the presence of kames and eskers are all 830 8 40 7 0 6 evidence that once the glacier stagnated over the Freeport East quadrangle and melted from the top Og 0 Silt (loess) with some thin lenses of sandy 0 8 0 loam. Commonly associated with ground 8 8 80 down. (Doyle, 1965). The glacial deposits that cover the area are generally referred to as the 2 Og 30 moraines. Occurs as an eolian deposit in 0 Qpr Glasford Formation. The drift is predominantly composed of glacial till, outwash sands and Qg 8 uplands, colluvium along slopes, and reworked 50 Qg alluvium within stream and river valleys. gravels, and silts. Qg 78 8 840 0 4 0 0 3 In the Freeport area there is approximately 2400ft of Paleozoic material that rest on a Precambrian 8 Qpr 0 Glasford Formation 86 6 Winnebago Formation basement (Cote et al., 1970). The bedrock geology of the area is dominated by Ordovician strata of Og 0 7 Qg 810 the Ancell, Galena, Platteville, and Maquoketa Groups (Kolata et al., 1978; Kolata and Graese, 0 Diamicton (till). Reddish-brown sandy clay 0 0 Qg 6 Qg 8 0 Og loam with distinct clay films on ped faces. 5- 1983; McGarry, 2000). The Ancell Group consists of the St. Peter and Glenwood Formations. The 7 0 4 79 toni 8 QwQg 10% gravel. Pecaton Qpr eca ca Galena and Platteville Groups are collectively more than 100 m (320 ft) in thickness and consist of ic P R a i 8 RivQc v Qh Og 40 e 760 780 e 8 7 layers of dolostone. The dolostone ranges from coarsely fossiliferous to micritic, and is locally r r 0 9 760 0 Qg 0 77Qg0 cherty and/or heavily bioturbated. Thin layers of bentonite also are present. Qh 750 0 0 Qc 9 760 6 7 ÏÎ 760 760 7 8 40 The major surface drainage feature within the Freeport region is the Pecatonica River. The 76 1 7 0 760 0 8 Ordovician System 7 770 1 6 8 0 Pecatonica River flows eastward along the northern border of Freeport, cutting through the 0 0 7 Qc Qc 0 7 P 0 northeastern portion of town. The river is approximately 30 m wide with a gradient of Qh e c 760 0 at 7 1 o 6 0 8 Maquoketa Shale approximately 0.13 m per km (Williams and Booth, 2002). The watershed associated with the n 7 7 0 ic 0 7 7 77 6 a 0 0 8 Qh 7 R 6 0 2 8 i 7 0 ve 0 8 Pecatonica River covers a total of 2,000 km in Winnebago, Stephenson, Jo Daviess, and Carroll r 0 7 7 Pe 8 5 Dolomitic silty, clayey, shale. catonica R 7 0 Qh 7 counties (Illinois Environmental Protection Agency, 2009). The watershed consists of a total 655 770 iv e 7 Lenses of dolomitic limestone are Qc 0 Om 800 r 80 km of stream (Illinois Environmental Protection Agency, 2009). Qpr 0 7 interbedded throughout. 6 7 Qc Data used to create this map were compiled from Illinois State Geological Survey water borehole 810 7 9 8 0 8 30 Qh Galena Platteville Dolomite records, field observations, seismic refraction analysis, and the United States Department of 6 8 0 84 Qh Qh 2 0 810 0 7 820 US 20 Agriculture soil survey maps. Electronic files were gathered from multiple state and federal agency 7 7 8 0 6 1 Qg Dolomitic limestone with chert 0 0 websites to determine elevation contours, roads, railroads, and water channels. 860 nodules. Partially weathered at 840 8 0 US Bus 20 800 780 7 1 8 810 85 Qh 70 0 2 Ogp 0 0 surface with evidence of karstic 8 0 Qh 840 7 5 8 features. 7 1 REFERENCES 8 0 0 0 840 Og 0 3 2 8 Berg, R. C., Kempton, J. P., Follmer, L. R., and McKenna, D. P., 1985, Illinoian and Wisconsinan stratigraphy and environments in northern Illinois: the Altonian revised, Champaign, IL, 8 Qh 0 8 0 1 0 0 7 0 Og 6 Illinois State Geological Survey Guidebook 19, Midwest Friends of the Pleistocene, 32nd Field Conference, 177 p. 9 8 9 7 0 0 7 7 0 0 Og 0 3 4 8 Cote, W., Reinertsen, D., Killey, M., 1970, Guide Leaflet: Geological Science Field Trip - Freeport area; Stephenson County (Freeport, Lena, and Pecatonica Quadrangles), Champaign, 5 800 7 6 0 8 7 90 IL, Illinois State Geological Survey Guide Leaflet 1970 C. 9 7 7 7 0 8 Og 0 8 0 8 0 7 2 8 0 5 0 4 0 Qpr Doyle, F. L., 1965. Geology of the Freeport Quadrangle, Illinois, Illinois State Geological Survey Circular 365. 6 0 7 8 6 7 0 k Frohling, D.K, Malone, D.H., and Shields, W.E. 2007, Geologic Map of the Ransom Quadrangle, LaSalle County, Illinois, Scale 1:24,000. Illinois State Geological Survey EDMAP Series 7 Water 0 e 0 Og #19.Frye, J. C., Glass, H. D., Kempton, J. P., and Willman, H. B., 1969, Glacial tills of northwestern Illinois, Survey, I. S. G., Champaign, IL, Circular 437, 47 p. 75 r e 81 llow C Og 79 Illinois Environmental Protection Agency, 2009, Source Water Assessment Program Fact Sheet: Freeport, Illinois Environmental Protection Agency.