Is the Cambrian Mount Simon a Regional “Blanket Sandstone” Across Ohio?

Baranoski, Mark T.¹ (1) Ohio Division of Geological Survey, Columbus, OH

Regional correlation and mapping of Cambrian sub-Knox units in the Ohio region indicates that the Mount Simon Sandstone was deposited on the underpinning Precambrian complex (Granite Rhyolite and Grenville Provinces and the East Continent Rift Basin) unconformity surface, in an area limited to western Ohio and the adjacent proto Michigan-Illinois basin. This recent analysis illustrates that the Mt. Simon is not a regional “blanket sandstone” extending across Ohio into the Appalachian basin as traditionally mapped. The Mount Simon's eastern limit is redefined along a NNW-trending broad Precambrian paleotopographic arch (exposed Laurentian craton), extending from an area north of present day western Lake Erie southward to the northwestern Rome Trough boundary fault system. The Mount Simon subcrops along the northern portion of this NNW-trending arch. Along the southern portion of this trend the Mount Simon becomes an eastwardly-thinning carbonate-dominated facies, where a major Precambrian paleotopographic high formed another barrier to Mt.Simon deposition on the ENE-trending shoulder of the Rome Trough. These regional basement highs controlled depositional facies and basin architecture of the proto Illinois-Michigan and Appalachian basins and Rome Trough. Following Mount Simon deposition, the Eau Claire Formation of western Ohio and a redefined Conasauga Group of eastern Ohio formed a regional platform dominated by cyclical mixed clastic-carbonate sediments throughout central Ohio; eastward this interval becomes primarily carbonates. The redefined sub-Knox of the Ohio region has implications for crustal and tectonic studies, basin analysis, hydrocarbon exploration, and reservoir studies for hydrocarbons, gas storage, industrial waste disposal, and CO2 sequestration.