Cordilleran metamorphic core complexes of the western US manifest large-scale Cenozoic crustal extension. Slip along the detachment faults documents lateral displacement, but other constraints on uplift and timing are required to develop realistic models of this phenomenon. Thermochronologic data have provided the best quantitative constraints on the cooling, uplift and slip rates, however inherent in the interpretation of these data is the assumption that cooling of the footwall occurred via conduction in response to uplift. Recent work has indicated the possibility that cooling occurred from advective extraction of heat from the lower plate by surface water flowing down the detachment. This project is aimed at testing this new idea. Results have many implications related to core complexes and rates of uplift.
