4-D Backstripping of the Michigan Basin and Its Implications for Intraplate Tectonics
Intracratonic Basins are features of continental interiors worldwide, including North America, which contains the Paleozoic Michigan, Illinois, Williston and Hudson’s Bay basins. While the geometry and internal structures of these basins are well known, high-resolution subsidence histories and the effects of regional tectonics during their development have not been explored in detail. The Michigan Basin was selected for this study due to an apparent lack of major internal deformation and the large amount of available well log data. A digitized set of over 57,000 well logs was subjected to quality assessment and quality control and subsequently backstripped. 3D plots of the results for each formation display the total and tectonic subsidence history of the basin during the Paleozoic. The plots confirm that the Michigan Basin was driven by a primary and long lived process characterized by a circular pattern of subsidence, which was punctuated by at least two periods of horizontal compression that were contemporaneous with the Taconic and Acadian orogenies in Eastern Laurentia. Mantle downwelling beneath the Michigan basin could account for the quasi-circular background subsidence, present in most recorded periods of sediment accumulation and generally centered to the west of Saginaw Bay. The Ordovician Taconic Orogeny tilted the basin eastwards, producing a significant increase in subsidence and a migration of the depocenter in the same direction. The effects of the Late Devonian Acadian Orogeny overprinted the dominant circular basin geometry producing a short-lived, but prominent linear region of negligible subsidence within backstripped Devonian formations. This anomalous region trends approximately northeast/southwest through the center of the basin and may represent the remnants of a failed cratonic arch, being sub-parallel to the Algonquin-Findlay and Wisconsin arches to the southeast and northwest of the basin, respectively.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009