Stratigraphy Along the 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 michvestern Indiana. Basal Pennsylvanian beds will be seen resting on Lower Chester, Ste. Genevieve, St. Louis, Salem, Harrodsburg, and Borden rocks representing a truncation of approximately 260 feet of sediments.