Physical Sciences and Mathematics Commons^™

Brittle Deformation In An Ancient Accretionary Prism Setting: Lopez Structural Complex, San Juan Islands, Nw Washington, John R. (John Rhea) Gillaspy

WWU Graduate School Collection

Fault-bounded slices of allochthonous Paleozoic to Mesozoic bedrock of the San Juan Islands in northwest Washington provide a locality in which to study terrane translation and ductile and brittle deformation in an accretionary wedge setting, as well as the factors involved in preservation of blueschist-facies terranes. This study contributes to understanding of the tectonic evolution of the Lopez Structural Complex, a major Late Cretaceous terrane-bounding fault zone in the San Juan Thrust System. Structural study is combined with X-ray diffraction and fluid inclusion analysis to constrain the relative timing, kinematics, and P-T conditions of fabric formation and post-fabric brittle deformation …