Revised Sub-Knox Lithostratigraphy for Ohio Indicates Complex Precambrian Paleotopography

Baranoski, Mark T.
Ohio Division of Geological Survey, Columbus, OH

During Mount Simon Sandstone depositional time, the Ohio region was not the Precambrian peneplain surface traditionally assumed by many previous workers. Preliminary mapping of revised Cambrian Sub-Knox units suggest that the Mount Simon and Conasauga Group were deposited on a complex Precambrian paleotopographic unconformity surface that included numerous monadnocks and, less commonly, incised river valleys and faulted terrain. A linear structural feature, termed the Rome Trough High, paralleled the northwestern edge of the Rome Trough failed aulacogen and provided regional tectonic control of Mount Simon and Conasauga deposition. This Rome Trough High was part of a regional paleotopographic basement high that separated the proto Illinois-Michigan Basin from the Rome Trough and proto Appalachian Basin. A Cambrian petroleum system is proposed for the region in which Conasauga Group organic-rich shales of the Rome Trough are in transitional facies contact with the interbedded dolostones and quartz arenites of the Conasauga Group of southeastern Ohio and adjacent areas of Kentucky and West Virginia. Although significant hydrocarbon production from the Conasauga has not been discovered to date outside of northern Kentucky and West Virginia, and Ontario, Canada, scattered shows within the Sub-Knox throughout the intervening region indicate the presence of a potential Cambrian petroleum system and new exploratory targets for the petroleum industry.

AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004