Evolution, Modification, and Deformation of Continental Lithosphere: Insights from the Eastern Margin of North America

Abstract

Continental lithosphere is deformed, destroyed, or otherwise modified in several ways. Processes that modify the lithosphere include subduction, terrane accretion, orogenesis, rifting, volcanism/magmatism, lithospheric loss or delamination, small-scale or edge-driven convection, and plume-lithosphere interaction. The eastern North American margin (ENAM) provides an exceptional locale to study this broad suite of processes, having undergone multiple complete Wilson cycles of supercontinent formation and dispersal, along with ∼200 Ma of postrift evolution. Moreover, recent data collection efforts associated with EarthScope, GeoPRISMS, and related projects have led to a wealth of new observations in eastern North America. Here I highlight recent advances in our understanding of the structure of the continental lithosphere beneath eastern North America and the processes that have modified it through geologic time, with a focus on recent geophysical imaging that has illuminated the lithosphere in unprecedented detail. ▪Eastern North America experienced a range of processes that deform, destroy, or modify continental lithosphere, providing new insights into how lithosphere evolves through time.▪Subduction and terrane accretion, continental rifting, and postrift evolution have all played a role in shaping lithospheric structure beneath eastern North America.▪Relict structures from past tectonic events are well-preserved in ENAM lithosphere; however, lithospheric modification that postdates the breakup of Pangea has also been significant.