Abstract: A New Geologic Interpretation of the Reprocessed Ohio COCORP Seismic Lines

DEAN, STUART L.
University of Toledo, Toledo, OH
JOHN L. WICKS
Red Bird Producing, Wooster, OH
MARK T. BARANOSKI
Ohio Division of Geological Survey, Columbus, OH

Reprocessed seismic data of the original (1987) Ohio Consortium for Continental Reflection Profiling (COCORP) line, to three seconds two-way time, reveal extensive Precambrian Grenville-age thrusting, with an east to west progression of thrusts extending further westward than previously reported. Grenville deformation apparently post-dated development of the East Continent Rift Basin, Precambrian Middle Run sedimentation and appears to have folded and transported some of the rift assemblages. The most striking feature on the line is the Central Ohio Platform (new term). This feature occurs in west-central Ohio and is coincident with a series of Grenville thrust sheets. A pronounced, broad, fault-bend anticline that is currently expressed as a basement high coincides with the Findlay Arch and Bellefontaine outlier and is the westernmost basement high on the Central Ohio Platform. The fundamental architecture of the Central Ohio Platform and Appalachian Basin may date from the time of Grenville deformation, although demonstrated stratigraphic effects defining the Basin date only to late Ordovician time.

A large number of extensional faults of Middle Cambrian (Mt. Simon-Rome) and older age are present from the Indiana border across the Central Ohio Platform as far east as Coshocton County. Some of these faults may be the result of re-activation and reversed (i. e. normal slip) movement on high-angle Grenville thrust faults. Well logs confirm the absence of Mt. Simon Sandstone on basement horst blocks and anomalously thick Mt. Simon and older sediments in grabens. Younger faults of Late Ordovician to Mississippian age define a series of terraces, bounded by monoclines, which step down eastward into the early Appalachian Basin and, in part, controlled facies distribution and subsequent hydrocarbon accumulation during the Paleozoic.

AAPG Search and Discovery Article #90930©1998 AAPG Eastern Section, Columbus, Ohio