Late Paleozoic tectonism in Nevada: Timing, kinematics, and tectonic significance

Three late Paleozoic, angular unconformities, each tightly constrained in age by biostratigraphy, are exposed in Carlin Canyon, Nevada. These record deformation as well as erosion. Folding associated with these deformation events is roughly coaxial; all three sets of fold axes trend northeast. Each unconformity represents tectonic disruption of the middle part of the western North American margin between the times of the initiation of the Antler orogeny (Late Devonian-Early Mississippian) and the Permian-Triassic Sonoma orogeny. This paper focuses on one of these unconformities in the Middle Pennsylvanian-the C6 unconformity-and the deformation and age constraints associated with it. Our data from Carlin Canyon yield detailed glimpses of how the Antler foreland evolved tectonically in Mississippian and Pennsylvanian time. Middle Pennsylvanian (Desmoinesian) northwest-southeast contraction resulted in thin-skinned folding and faulting, uplift, and erosion. These data require reinterpretation of the tectonic setting at the time of the Ancestral Rocky Mountains orogeny and suggest that plate convergence on the west side of the continent played a significant role in late Paleozoic tectonics of the North American continent.