North American APW during the Jurassic: An Answer from the Black Hills

Western Washington University, Bellingham WA

Investigators

Abstract

0073891 Housen North America experienced tectonism on both east and west margins during the Mesozoic, and paleomagnetic data have been instrumental in working out past relative plate positions and relative motion. However, the apparent polar wunder path for North America, on which accurate reconstruction rely, is basically unresolved for the middle and upper Jurassic. Data from New England suggests that the APWP lies at high latitudes, but data from the Colorado Plateau indicates a significantly lower latitude APWP. This discrepancy is important, and remains unresolved because flaws exist in both data sets. This project will attempt to define the APWP for this time interval for North America by study of the Sundance and Morrison formations in the Black Hills of Wyoming and South Dakota that may have escaped the rotations and overprints affecting other regions. Results will help anchor poles of middle to upper Jurassic age for cratonic North America so that several tectonic questions can be better addressed.