Paper No. 8
Presentation Time: 10:45 AM
SOUTHEAST U.S. LITHOSPHERE EXPERIMENT – CONTINENTAL GROWTH AND MANTLE DYNAMICS (SEUSLE)
Passage of the USArray component of EarthScope across the southeastern United States is an unprecedented opportunity to investigate past tectonic events that played a major role in the growth of the North American continent. We describe an experiment involving the TA and a FlexArray deployment designed to provide an overall framework of lithospheric velocity and anisotropy structure within a major portion of the southeast U.S. while targeting several tectonic features critical to our understanding of past collisional and extensional events. Tying three FlexArray profiles in our experiment with profiles in two existing EarthScope experiments will provide the coverage needed to construct meaningful models for these critical features. Major issues we wish to address are 1) properly characterizing the basement feature associated with the New York-Alabama magnetic lineament, a pronounced magnetic gradient associated with the east Tennessee seismic zone, 2) the location of the Grenville Front, the major tectonic boundary associated with the formation of the supercontinent Rodinia, 3) the extent of rifted crust east of the Mississippi Valley Graben (host of the New Madrid seismic zone) that could pose elevated seismic hazard, 4) the crustal and mantle structure associated with the Appalachian gravity gradient, 5) the mantle expression of continental collision and subsequent rifting associated with the Suwannee-Wiggins suture zone, and 6) the presence of anisotropic fabric within the lithosphere that is indicative of past, major orogenic events and sublithospheric anisotropy that can be used to discriminate between various mantle flow models proposed for the southeastern U.S. The results of our study will help provide answers to many outstanding questions regarding the growth of the continent in the southeast U.S. and help reveal how ancient tectonic events continue to influence the present via inherited lithospheric structure and seismic activity.