9316916 Jacobson The Late Cretaceous-early Tertiary aged Chocolate Mountains thrust is part of a major, extensive fault zone in SE California that places Precambrian to Mesozoic gneisses over Cretaceous high pressure/low temperature schists. The transport direction is toward the NE and this has been used to help reconstruct a large part of the SW Cordillera during Cretaceous times. Recent work has shown that several sections of this major fault zone, including the Chocolate Mts. thrust, may have been reactivated and that they therefore may represent exhumation rather than subduction and burial tectonism. This project will resolve the controversy by detailed field work with structural and metamorphic petrology. The results will allow meaningful plate reconstructions for the Mesozoic to Tertiary in the SW Cordillera, and will have implications for similar tectonic settings in other major orogenic belts.
