9304021 Evans This research proposal combines field work, structural measurements and interpretation, petrography, phase petrology, thermobarometry, and isotopic age determinations in the Nason Terrane of the state of Washington. The purpose of the study is to examine critically the field evidence on which the recently proposed tectonic model termed magma loading is based. The model implies coincidences in timing between plutonism, metamorphism and deformation, spatial relationships among plutons and the distribution and history or pressure and temperature, and flexuring events producing and then eliminating steep baric gradients. The proposed research has major implications for crust-building and metamorphic processes in large-volume magmatic arcs.
