Paleomagnetic and (40)Ar/(39)Ar Results from the Grant Intrusive Breccia andComparison to the Permian Downeys Bluff Sill. Evidence for Permian Igneous Activity at Hicks Dome, Southern Illinois Basin

摘要

Studies of igneous rocks in southern Illinois contribute to multidisciplinaryinvestigations of the thermal activity, fluid-flow history, hydrocarbon generation, and mineralizatin in and around the Illinois Basin. In this study, we apply 40Ar/39Ar dating methods, along with paleomagnetic and rock magnetic techniques, to determine the age of emplacement and the cooling history of the Grant intrusive breccia at Hicks dome.