Dextral strike-slip faults play a major role in the disruption of the collage of accreted terranes in Washington and British Columbia. The major goal of this project is to place firm structural and geochronlogic constraints on one of the major fault zone in this region, the Ross Lake fault zone, which disrupts several terranes and was active during metamorphism and plutonism in the adjacent crystalline core of the North Cascades. The kinematics of mylonite belts in the fault zone will be determined through detailed mapping, study of small-scale structures and kinematic indicators, while the timing of movement will be constrained by dating plutonic bodies in the fault zone which show varying degrees of deformation and metamorphism. Results should substantially increase knowledge of the late Mesozoic - early Cenozoic history of the crystalline core of the North Cascades.
