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.