Understanding the thermal and fluid flow consequences of thrust faulting is necessary to understanding heat and mass transfer processes in the earth's crust. Many thrust faults preserve an inverted metamorphic gradient in their footwall rocks, but the mechanisms to produce this are poorly understood. This study will constrain the mechanisms of metamorphism and fluid flow associated with prograde inverted metamorphic gradients in supracrustal rocks of the footwall in two ranges in western Arizona. It will also test the hypothesis that fluids released during the prograde metamorphism migrated upwards and caused retrograde metamorphism in the crystalline rocks of the hanging wall. The approach will be an integrated study of structures, petrology, stable isotopes, fluid inclusions and 40Ar/39Ar systematics. The results will constrain the mechanisms that produce inverted metamorphic gradients, and will increase the understanding of heat and mass transfer processes associated with tectonic events.
