Stratigraphy and composition of the Sharon Springs Member of the Pierre Shale in western Kansas

Abstract

The Sharon Springs Member of the Pierre Shale is a widespread unit that can be recognized readily in outcrops by its distinctive lithologic character and in the subsurface by electric and gamma-ray well-log characteristics. The Sharon Springs Member is in Kansas, Nebraska, North and South Dakota, and parts of Colorado, Wyoming, Montana, and eastern Utah. Its type locality is in Wallace County, Kans., where the member is about 215 feet thick and consists of three units: a lower dark soft shale unit 115 feet thick, a middle hard organic-rich shale unit 90 feet thick, and an upper hard slightly phosphatic shale unit about 10 feet thick. The Sharon Springs contains abundant vertebrate remains but few mollusks.