9417711 Peacock The geology and structure of many metamorphic core complexes is reasonably well-known, however rates and duration of extension and thermal effects, particularly in the upper plate, are not well- constrained. This project will utilize the well-characterized Catalina metamorphic core complex to address these questions by determining apatite and zircon fission-track ages and track length distributions for samples collected from both the upper and lower plates. Results will help constrain the timing, duration and rate of extension, the magnitude of crustal extension and thermal effect of extension on the upper plate. A rigorous thermal modeling program will guide interpretation of the FT data and should increase our understanding of the thermal evolution of the crust during extension.
