Summary:

The presence of circa 0.95–1.3 billion-year-old and circa 300–480 million-year-old detrital zircon grains in Upper Mississippian and younger strata of the Grand Canyon (Arizona), and the absence of these populations in older strata, mark the arrival of Appalachian Mountains–derived detritus in the western United States. This observation led to an interpretation that Appalachian-derived material was transported westward via large rivers, coastal currents, and trade winds. While it is not difficult to envision delivery of Appalachian detritus hundreds of kilometers to the west via clastic wedges and documented paleoriver systems, numerous intervening basins, paleotopographic highs, and inland seas would have presented significant obstacles to westward sediment transport. Hence, tracing the specific Appalachian-to-Grand-Canyon sediment dispersal path is a necessary step in evaluating the transcontinental transport hypothesis and ruling out alternate sources. 

This work tests possible transcontinental sediment pathways using existing detrital zircon uranium-lead data from Ordovician to Pennsylvanian strata exposed across North America and filling gaps in coverage with new data from the Black Hills (South Dakota); the Ozark Dome and Illinois Basin (Missouri); the Madison, Bridger, and Big Snowy ranges (Montana); and drill core from Kansas.

Biography:

I study the tectonics of continental margins, focusing on the North American Cordillera and the Central Andes.  My professional preparation includes B.S. degrees in Geology and Geophysics from the University of Minnesota (2005) and a Ph.D. from the California Institute of Technology (2011).  I have held postdoctoral positions at the University of Arizona (2011-2013) and Stanford University (2013-2015), and assistant professor positions at Missouri S&T (2013-2015) and Macalester College (2015- ).