Physical Sciences and Mathematics Commons^™

Structural Geology Of The Central San Juan Islands, Northwest Washington, Todd I. Belanger

WWU Graduate School Collection

Within the Late Cretaceous San Juan thrust system, northwest Washington, tectonically juxtaposed melange separates the relatively unmetamorphosed, arc-affinity Fidalgo Complex and the high pressure-low temperature, MORB-affmity Ocean Floor terrane. Structural analysis. X-ray diffraction, and fault-slip analysis are used to constrain the relative timing, kinematics, and pressure-temperature conditions of postfabric ductile and brittle deformation in the Fidalgo Complex, Ocean Floor, and melange. Structural analysis of the melange, Fidalgo Complex, and Ocean Floor terranes help to constrain the tectonic development of the structurally highest terranes in the San Juan thrust system and provide insight into the mechanisms required for uplift of high-pressure …