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Kinematic Analysis Of Ductile Features Within The Northern Wenatchee Block, North Cascades, Washington, Gerald Griesel

WWU Graduate School Collection

The Cascade crystalline core of Washington State is a block of high grade metamorphic and plutonic rocks at the southeast end of the Cretaceous-Tertiary Coast Plutonic Complex. Previous workers have debated whether northwest translation or southwest-vergent thrusting was responsible for regional metamorphism and deformation. The present study finds structural evidence supporting both orogen-normal and orogen-parallel displacements, thus indicating that the regional deformation can be broadly characterized as transpressional.

Units of the study area include: 1) the Napeequa schist, derived from an ocean floor protolith, and 2) an accreted Triassic arc, which includes the Marblemount Meta Quartz-Diorite (MMQD) and metamorphosed volcanic …