KGS--Sumner County--General Geology

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General Geology

Summary of Stratigraphy

The classification and nomenclature of the rock units described in this report have been adopted by the State Geological Survey of Kansas. They differ somewhat from the usage adopted by the U.S. Geological Survey.

The rocks that crop out in Sumner County are sedimentary in origin and range in age from Paleozoic to Recent (Pl. 1). The oldest rocks are a part of the Wellington Formation of the Leonardian Stage, Permian System. The Wellington Formation forms the bedrock surface in approximately the eastern two-thirds of the county and crops out in local areas where it is not covered by Pleistocene deposits. The Ninnescah Shale, also of the Leonardian Stage, forms the bedrock surface in approximately the western third of the county and crops out in local areas where it is not covered by Pleistocene deposits.

Cenozoic deposits of the Pleistocene Series representing four glacial stages and possibly the interglacial stages occur in Sumner County. Deposits of Nebraskan-Aftonian age underlie the surface in the northwestern part of the county near Conway Springs. Deposits of Kansan-Yarmouthian age are most extensive in the eastern and southern parts of the county. Illinoisan-Sangamonian and Wisconsinan terrace deposits border most of the major streams of the county, and Recent deposits form the flood plains and occur also as sand dunes. Deposits of the interglacial stages were not recognized, however, and therefore in this report the deposits referred to a glacial stage include those of the subsequent interglacial stage if present. Deposits of Kansan and Illinoisan age are mapped together on Plate 1.

A generalized section of the rocks that crop out in Sumner County is given in Table 3.

Table 3--Generalized section of rocks* that crop out in Sumner County and their water-bearing characteristics.

System	Series	Subseries	Stage	Stratigraphic unit	Thickness, feet	Physical character	Water supply, Sumner County
Quaternary	Pleistocene	Upper Pleistocene	Recent	Dune sand	0-30	Sand, medium and fine, some silt	Generally above the water table, and does not yield water to wells
				Alluvium	0-75	Chiefly arkosic sand and gravel; contains discontinuous lenses of silt and clay	Yields large quantities of water to wells
				Colluvium Recent to Illinoisan	0-25	Silt and clay, minor amounts of sand and gravel, resembling the underlying bedrock material	Does not yield appreciable quantities of water to wells
			Wisconsinan	Colluvium Recent to Illinoisan	0-25		Does not yield appreciable quantities of water to wells
			Wisconsinan	Terrace deposits	0-75	Chiefly arkosic sand and gravel; contain discontinuous lenses of silt and clay. Can be differentiated from alluvium only by topographic position	Yield large quantities of water to wells
			Illinoisan	Crete Formation	0-65	Poorly sorted sand and gravel; contains considerable red-brown silt and locally derived limestone and shale fragments	Yields moderate quantities of water to wells
		Lower Pleistocene	Kansan	---	0-90	Poorly sorted sand and gravel; locally contains much silt and clay	Yields moderate quantities of water to wells
		Lower Pleistocene	Nebraskan	Terrace deposits	0-90	Chiefly medium to coarse sand; contain some silt and clay	Yield moderate quantities of water of good quality to wells
Permian	Middle Permian	---	Leonardian (Sumner Group)	Ninnescah Shale	0-250	Predominantly silty shale, mostly brownish red with gray-green spots; contains beds of dolomite, calcareous siltstone, and fine-grained sandstone	Yields small quantities of hard water to wells
Permian	Middle Permian	---	Leonardian (Sumner Group)	Wellington Formation	40-650	Chiefly shale and silty shale, mostly gray and green, some red; contains lenticular beds of gypsum, silty limestone, dolomite, and the thick Hutchinson Salt member near base	Yields small quantities of hard water to wells

* The classification is that of the State Geological Survey of Kansan

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Kansas Geological Survey, Geology
Placed on web January 2003; originally published August 1961.
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