The Mojave desert between the San Andreas and the Garlock fault zones occupies a key position in Southwestern U.S. tectonics. Recent results indicate that a previously unrecognized region of early Miocene-age rifting is present which has led to the discovery of Mesozoic tectonometamorphic events as well as to an improved understanding of present strike-slip faulting in the region and its role in accommodating Pacific- North American plate motion. This renewal will focus on the structure, timing relations, shear zone petrology and uplift history of the extensional complex, and will document the depositional history of syn-and post-tectonic sedimentary rocks in basins adjacent to the core complex. The timing and conditions of formation of the Mesozoic high-grade metamorphic rocks exhumed by Miocene detachments will also be addressed. Results will be applied to the Mesozoic and Cenozoic tectonic and paleogeographic evolution of the western United States.
