Geology and its Relation to Ground Water, continued
Pre-Permian rocksPre-Permian rocks are not exposed in Barton and Stafford Counties, and their nearest outcrops are in the eastern part of the state, more than 100 miles east of the area under consideration. Knowledge of the character and distribution of these older rocks in central Kansas has been obtained by various geologists by studying the samples and logs of the deep oil wells that have been drilled in this area. The discussion of the Pre-Permian rocks in Barton and Stafford Counties that is given below is based mostly on data obtained from Wallace Lee (oral communication), geologist of the Federal and State Geologic Surveys, but in part on reports by Moore and Jewett (1942), Koester (1935), and Ver Wiebe (1938).
The oldest rocks encountered by deep drilling are granite, schist, gneiss, and other types of igneous and metamorphic rocks of Precambrian age. These rocks form the "basement" of Kansas, and in Barton and Stafford Counties they are encountered at depths ranging from about 3,500 feet to about 5,000 feet below the surface. Unconformably overlying the Pre-Cambrian "basement" rocks are sandstone, sandy dolomite, and dolomite (Arbuckle group and Lamotte sandstone) of Cambrian and Ordovician age, the oldest sedimentary rocks in this area. They are missing entirely in parts of west-central Barton County and attain a thickness of more than 600 feet in southern Stafford County. The Arbuckle group is one of the most important oil-producing zones in this area.
Rocks of Ordovician age include the Simpson group and the Viola limestone. The Simpson group, which consists of green shale and sandstone, occurs only in the southern half and along the eastern edge of Stafford County where it is generally less than 100 feet thick. Oil has been found in the Simpson group in northeastern and south-central Stafford County. The Viola limestone is found only in the southern two-thirds of Stafford County. It lies on the Simpson group in the southern half of the county and overlaps onto older rocks of the Arbuckle group to the north. The thickness of the Viola limestone in this area is everywhere less than 100 feet and in most places is less than 50 feet. It is an important oil-producing formation in the Stafford-Zenith area.
No strata of Silurian age have been encountered in Barton and Stafford Counties. The Chattanooga shale of Mississippian or Devonian age unconformably overlies the Viola limestone in southeastern Stafford County but is missing elsewhere. The thickness of the Chattanooga shale is 100 feet or less. Mississippian limestone and shale having a thickness of 75 feet or less are present in approximately the southeast quarter of Stafford County. These strata overlie the Chattanooga shale where it is present and overlap the older Viola limestone to the north.
Pennsylvanian rocks, consisting predominantly of limestone and shale, underlie the entire area under consideration. They range in thickness from about 1,200 feet in Barton County to 1,400 feet in southern Stafford County. Their base is marked by a prominent unconformity. In southeastern Stafford County, Pennsylvanian strata lie above Mississippian rocks; in west-central Barton County they lie on Pre-Cambrian rocks; elsewhere, they are found on Cambrian or Ordovician rocks. The Pennsylvanian System includes the important oil-producing rocks of the Kansas City and Lansing groups.
The upper part of the Permian System (Guadalupian-Leonardian Series) is chiefly nonmarine in origin and is composed of red silt-stone, shale, and sandstone with lesser amounts of salt, gypsum, anhydrite, limestone, and dolomite. The salt beds in this area are from less than 50 feet to about 200 feet thick and are encountered about 1,000 feet below the surface (Bass, 1926, p. 90). The lower part of the Permian system (Wolfcampian Series) is largely marine in origin and is composed chiefly of limestone, dolomite, and shale but also contains some sandstone and anhydrite.
No wells obtain water from Permian rocks in Barton and Stafford Counties. Adequate supplies of water are available to wells in most places from rocks overlying the Permian. Furthermore, water obtained from Permian rocks in this area probably would be too highly mineralized f or most ordinary uses. A sample of water collected from test hole 22-11-5dc3, which penetrated Permian rocks in sec. 5, T. 22 S., R. 11 W., northeastern Stafford County, contained 8,688 parts per million of dissolved solids and 4,730 parts of chloride, and had a total hardness of 1,386 parts (analysis 22-11-5dc3, Table 10).
Kansas Geological Survey, Barton and Stafford County Geohydrology|
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Web version Dec. 2001. Original publication date Dec. 1950.