Resolving space-time strain paths of the Panamint and Cottonwood mountains, eastern California, through bedrock and detrital thermochronology

This research focuses on the history of extensional and strike-slip deformation in the Panamint Range and southern Cottonwood Mountains, west of Death Valley. Faults in these ranges are important because they accommodate a substantial portion of the Miocene to recent plate boundary strain, east of the Sierra Nevada. Although a number of field-based investigations have been completed in these ranges, published displacement paths for individual ranges are variable. Evidence for Late Cretaceous to Eocene exhumation in the footwalls of detachments in the region also suggest that strain magnitude may not be well resolved. Here we reconstruct the Neogene motion of these ranges using a combination of bedrock and detrital (U-Th)/He thermochronology. We collected 38 samples from Jurassic to Miocene plutons and stocks in three transects and at various sites in these ranges. Samples were collected from granitoids of the Skidoo, Hall Canyon, and Manly Peak plutons in footwall of the Panamint-Emigrant detachment (PED) in the Panamint Range, and from quartz monzonites of the Hunter Mountain batholith in the southern Cottonwood Mountains. Samples were also collected from three major-basin filling units of the Nova Basin that record the late Miocene to Pliocene exhumation history of the range. The bedrock (U-Th)/He ages will be used to evaluate age versus paleodepth trends and to explore likely temperature-time histories using forward and inverse modelling approaches. Age data from the Nova Basin will be compared to ages from the footwall of the PED to evaluate similarities and differences in preserved cooling histories and the robustness of basin sediments and double-dating approaches in capturing the exhumation history of a range. The results will provide new constraints on the magnitude of cooling, timing of fault initiation, fault slip rates, and geothermal gradient, and an independent test of published space-time strain paths.