Paleogeographic reconstruction of Mississippian to Middle Pennsylvanian basins in Nevada, southwestern Laurentia

Abstract

Compilation of stratigraphic, sedimentological, and structural data on palinspastically restored maps reveals the Mississippian-Pennsylvanian paleogeography of Nevada in unprecedented detail, and has important implications for the development of the southwestern Laurentian margin. In contrast to previous interpretations of latest Devonian-earliest Mississippian tectonism, the maps show the major tectonic events to have been in late Middle Mississippian and Middle Pennsylvanian time. Regionally extensive unconformities mark both, with the deepest erosion in the northwest. Sub-unconformity structures record primarily NW-SE shortening, and synorogenic sediments were shed toward the east, southeast and south. These observations are consistent with protracted sinistral-oblique convergence in Nevada along the southwest Laurentian margin, rather than the W-E convergence invoked in previous interpretations. Terminology for late Paleozoic orogenies in Nevada must be revised accordingly. • Southwestern Laurentia experienced NW-SE shortening in the late Paleozoic. • Major tectonic evens in late Middle Mississippian and Middle Pennsylvanian. • Data consistent with sinistral-oblique margin throughout the late Paleozoic. • Data presented here are not consistent with E -W convergence in late Paleozoic.