Title: Geophysical Extent of the Wyoming Province: Insights into Ancient Subduction and Craton Stability
Abstract: The Wyoming Province, part of the Archean core of North America, is the subject of ongoing studies of continent evolution and stability as well as recent interest into the Province’s critical mineral endowment. I will present a recent 3-D resistivity model, estimated from inversion of magnetotelluric data, which images the lithospheric structure of the Wyoming Province and adjacent areas. Prominent high-conductivity belts define the margins of the Province and are interpreted as sutures marking the remnants of Paleoproterozoic orogens. In contrast, a Neoarchean boundary internal to the province is not marked by high-conductivity, a difference speculated to reflect changes in the subduction process through time. The Wyoming Province has also been proposed to have undergone lithospheric modification that lessened its stability, however our 3-D model suggests a thick lithospheric root remains in place except along the western margin of the Province. These results suggest Archean cratons may be more resistant to lithospheric modification than previously thought, and that the influx of heat and fluids from mantle plumes or lithospheric extension do not necessarily set cratons on a path to destruction.
Biography: Paul Bedrosian is a research geophysicist at the U.S. Geological Survey within the Geology, Geophysics and Geochemistry Science Center. His expertise is in the development and application of electromagnetic geophysical methods to framework tectonics, resource assessment, natural hazards and fundamental Earth processes. His work has investigated seismic variability along the San Andreas Fault, tectonics of the Pacific Northwest and Upper Midwest, and the structure of Mount St. Helens. His current research is on regional-scale mineral-resource investigations, the magmatic/hydrothermal systems of active volcanoes and the importance of solid-earth conductivity to space-weather hazards. Paul received B.S. degrees in chemistry and physics from the University of Minnesota in 1996 and a Ph.D. in physics from the University of Washington in 2002. He was an Alexander von Humboldt fellow at the GeoForschungsZentrum-Potsdam before joining the U.S. Geological Survey in 2005.
To join virtually: Zoom
Contact: pbedrosian@usgs.gov
USGS staff profile page: https://www.usgs.gov/staff-profiles/paul-a-bedrosian
Recording: Zoom Recording (will be available within a week after the seminar)