by William D. Johnson, Jr., and W. L. Adkison
Originally published in 1967 as U.S. Geological Survey Bulletin 1215-A, prepared in cooperation with the State Geological Survey of Kansas as a part of a U.S. Department of the Interior program for the development of the Missouri River basin.
This is, in general, the original text as published in 1967. The information has not been updated. Volume B, Geology of Western Shawnee County, Kansas, and Vicinity, is also online.
The eastern Shawnee County and vicinity study area, encompassing about 355 square miles of northeastern Kansas, was mapped as part of a study of Upper Pennsylvanian rocks. The area includes eastern Shawnee County and parts of southeastern Jackson, southwestern Jefferson, and westernmost Douglas Counties. Topographic coverage is provided by the Elmont, Grantville, Meriden, Richland, Topeka, and Wakarusa 7 1/2-minute quadrangles and the northernmost parts of the Carbondale and Overbrook quadrangles.
The unexposed sedimentary rocks in the area range in age from Late Cambrian to Late Pennsylvanian and are as much as 2,700 feet thick. Biotite granite of the Precambrian basement complex has been penetrated in two wells.
Exposed sedimentary rocks in the area are about 725 feet thick and are in the Shawnee and Wabaunsee Groups, of Late Pennsylvanian (Virgil) age. Relatively thick shale formations of claystone, siltstone, and sandstone and alternating thinner limestone formations record a cyclic pattern of deposition. The shale formations were deposited largely under nonmarine conditions. The limestone units were deposited largely under marine conditions ranging from beach or extremely shallow water to deeper, fairly quiet water of normal salinity. The claystone and siltstone in the limestone formations were deposited in estuarine, shallow lagoonal, and normal-marine environments. The widespread Nodaway coal bed of the Howard Limestone was deposited during subaerial conditions. Local channels have eroded several formations, particularly the Topeka and Howard Limestones.
Scattered deposits of chert gravel of pre-Kansan age occur in the area but are too small to map. Kansan glacial drift, consisting mainly of unstratified and unsorted clay till, covers most of the area. Thick deposits of stratified glacial outwash occur along the Kansas and Wakarusa Rivers.
Alluvial material of Quaternary age fills the Kansas and Wakarusa River valleys and the valleys of the larger creeks. In the Kansas River valley, extensive deposits correlated with the Newman terrace of Wisconsin age occupy much of the valley floor, and a broad band of Recent alluvium borders the river In the Wakarusa River valley the alluvial fill is also correlated with the Newman terrace, but small terrace remnants, questionably correlated with the Buck Creek terrace of Illinoian age, locally occur along the valley sides.
The mapped area is in the western part of the Forest City basin. Outcropping rocks in the area strike about N. 20°-30° E. and dip northwest, generally 20-40 feet to the mile. The regional dip is interrupted by minor folds, a few of which have almost 20 feet of closure.
No oil or gas in commercial quantities has been discovered in the area, but in several test wells slight oil stains have been found in rocks in the part of the Hunton Formation that is of Devonian age and in the Simpson Group, of Middle Ordovician age. Coal was formerly mined from the Nodaway coal bed of the Howard Limestone at many localities, particularly around Topeka, but the mines are no longer in operation. Limestone and river sand and gravel are being quarried commercially.
Kansas Geological Survey, Geology
Placed on web October 2005; originally published 1967.
Comments to email@example.com
The URL for this page is http://www.kgs.ku.edu/General/Geology/Shawnee/E/index.html