GSA Connects 2021 in Portland, Oregon

Paper No. 202-1
Presentation Time: 8:05 AM


VAN DER PLUIJM, Ben, Dept of Earth & Environmental Sciences, Univ of Michigan, 1100 N University Ave, Ann Arbor, MI 48109 and MARSHAK, Stephen, Department of Geology, University of Illinois at Urbana-Champaign, 3081 Natural History Building, 1301 W. Green St., Urbana, IL 61801

The Continental Interior of the United States lies east of the Cordilleran Orogen, west of the Appalachian Orogen, and north of the Ouachita Orogen. The region comprises the southern third of North America's craton, the relatively cold and strong portion of the continent that assembled during multiple crust-forming and collisional events between about 4.3 and 0.9 Ga. Since that time, the interior has not undergone mountain building or regional dynamothermal metamorphism, in contrast to the continent's marginal Phanerozoic orogens. But the North American plate interior was not ‘dead’ during the Phanerozoic; instead, the area preserves a distinct style of regional deformation. Specifically, we observe km-scale vertical displacements that led to the formation of regional-scale basins and domes, Great Unconformity topography, fault systems that cut and displace Phanerozoic strata and locally warp them into monoclinal folds, and fluid flow that triggered pulses of regional diagenesis. This signature of vertical tectonics in the continental interior differs from that of plate margin deformation, where lateral tectonics along plate boundaries dominates. The US continental interior provides important insight into the evolution and stabilization of the lithosphere over time and challenges the plate tectonics simplification of plate rigidity.