Evidence for from Appalachian Basin Source for Oils from the Findlay-Kankakee Arch Region, Indiana and Ohio

Elisabeth L. Rowan¹, Joseph R. Hatch², Christopher S. Swezey¹, and Robert T. Ryder^1
1U.S. Geological Survey, Reston, VA
²U.S. Geological Survey, Denver, CO

Oil and gas fields of the Lima-Indiana-Trenton trend (NE Indiana and NW Ohio) occur on a structural platform at the Findlay-Kankakee arch junction, bounded by the Illinois, Michigan, and Appalachian basins. Geochemical analyses of the oils indicate that they were derived from source rocks of Ordovician age. Ordovician source rock intervals occur within the Ancell, Galena and Maquoketa Groups in the Illinois basin, the Trenton Limestone and Collingwood Shale in the Michigan basin, and the Utica Shale in the Appalachian basin. Burial/thermal history modeling, constrained by vitrinite reflectance (Ro) and conodont CAI data, indicates that Ordovician rocks are thermally immature over the arch region. Hydrocarbons must therefore have migrated from a more distant, thermally mature source. Significant areas of Ordovician rocks in the adjacent basins had entered the oil window by the time of maximum burial in the mid-Permian. From a structural viewpoint, hydrocarbons could have migrated to the Findlay-Kankakee arch from any of the three adjacent basins.

The provenance of the Findlay-Kankakee arch oils is most definitively identified by their characteristic chemical ‘signature’, based on gas chromatograms and GC-MS fragmentograms (m/z=191). The Findlay-Kankakee oils show a strong similarity to oils from central Ohio which have an Appalachian basin/Utica Shale source, and dissimilarity to oils from the Illinois and Michigan basins. The chemistry thus indicates that the Findlay-Kankakee arch oils were derived predominantly from the Appalachian basin, with possible minor contributions from the Michigan and/or Illinois basins. Alleghenian orogeny-related groundwater flow westward through the Appalachian basin, proposed in a number of studies, may have enhanced buoyancy-driven westward migration of hydrocarbons from the Appalachian basin, particularly in areas of shallow dip.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas