Stratigraphy Along Mississippian-Pennsylvanian Unconformity of Western Indiana

Abstract

The Mississippian-Pennsylvanian unconformity is the most pronounced and extensive break in the Paleozoic rocks of the Eastern Interior Basin. During the long erosional interval Mississippian beds were truncated and a topographic surface of considerable relief was developed. Pennsylvanian sediments rest on Upper Chester beds in southwestern Indiana, on Meremacian limestones in midwestern Indiana and on Osagian and upper Devonian beds in northwestern Indiana. Outcrops selected for the 1950 Field Conference show the Mississippian-Pennsylvanian unconformity and the stratigraphy along the unconformity in midwestern Indiana. Basal Pennsylvanian beds will be seen resting on Lower Chester, Ste. Genevieve, St. Louis, Salem, Harrodsburg, and Borden rocks representing a truncation approximately 260 feet of sediments. This conference was planned to observe and discuss problems associated with a portion of the Mississippian-Pennsylvanian unconformity. Mississippian stratigraphy will be emphasized, and special attention will be given to the old Mississippian topography and to the lithology of the basal Pennsylvanian beds. We hope that discussion combined with actual field observation will be of mutual benefit.