Late Paleozoic Tectonostratigraphic Framework of the Western North America Continental Margin

Abstract

The late Paleozoic continental margin of western Pangea was in tectonic flux from at least the mid-Paleozoic Antler orogeny through the Late Permian–earliest Triassic Sonoma orogeny. This tectonism is registered by the periodic and apparent synchronous initiation and/or disruption of sedimentary basins and their associated paleogeographic highs along the entire length of the continental margin. The continental margin was not “passive” during the late Paleozoic, as is commonly believed. The possible tectonic drive(s) for this tectonism are problematic and include (1) terrane–continent collisions, (2) transpression and transtension along a long-lived translational margin, (3) far-field stresses related to continent–continent collision along the Appalachian–Ouachita–Marathon margins, and (4) shifts in mantle-plate interactions and resulting changes in global plate motions and intraplate stresses. Regardless of the specific tectonic driver, it must encompass the periodic and synchronous nature of these tectonic events and factor in the influence of preexisting crustal structures.