MICHIGAN BASIN ISOPACH MAPS REVEAL LOCAL VARIATIONS IN TOPOGRAPHY

The Michigan Basin is an intracratonic basin that contains sediments that originate primarily from six separate sources across North America. Our research group has obtained detrital zircon data from the Michigan Basin that shows there are four distinct sediment signals that are present within this basin in the Paleozoic stratigraphy: Craton dominated ( >50% of U-Pb ages 3.0 – 2.5 Ga), Grenville dominated ( >50% of U-Pb ages 1.3 – 0.95 Ga), Juvenile Crust dominated ( >40% of U-Pb ages 2.0 – 1.8 Ga), and Granite-Rhyolite dominated ( >40% of U-Pb ages 1.5 – 1.3 Ga) sediment signals. The detrital zircon data shows that in the Cambrian to middle Devonian strata, there are multiple sediment signals deposited at that same time that show there is little to no mixing of these different sediment sources from samples taken as little as ~ 100km apart. We see this in the Mount Simon sandstone during the Cambrian, the St. Peter sandstone during the Ordovician, and in early to middle Devonian aged formations. My project uses isopach data derived from oil and gas drill logs across Michigan and Indiana to investigate the potential existence of physical barriers within the Michigan basin that might have prevented sediments from mixing in such small distances. Furthermore, the isopach data will be used to see if these barriers could be linked to local variations in sediment thicknesses that resulted in topographic high-points that shed sediment.