The role of transcurrent faulting during Late Cretaceous to early tertiary deformation associate with terrane accretion to northwest North America is controversial, and several different hypotheses exist to explain the evolution of the orogen from Washington north into Canada. This project will collect data on displacement history (sense of shear through time), the Pressure-Temperature conditions during deformation and the age of movements along two major basin-bounding faults, the Pasayten and Entiat faults in northwestern Washington. Results will help elucidate the relative importance of contractional and transcurrent structures in one of the major Late Mesozoic orogenic belts of North America, and more fundamental questions regarding the role of transcurrent faults near convergent margins.
