During deformation in accretionary complexes, sediments undergo large volume losses spawning active hydrologic systems. The consequent fluid flow affects virtually all aspects of the complex's tectonic evolution and must be understood to evaluate this process. This study will investigate a Neogene accretionary complex on the Washington State continental margin. Mapping will be conducted along cliff exposures and the tidal zone where contacts between melange zones and normal sediments are exposed. The structural petrography of associated veins and cements will be examined and fluid inclusions analyzed to characterize the nature of rock-fluid interactions that were operative. Results will address to what extent melange zones are conduits for fluids and will help define hydrologic systems in actively deforming accretionary complexes.
