Physical Sciences and Mathematics Commons^™

Petrology Of The Crystalline Rocks Of Vedder Mountain, British Columbia, Mitchell L. Bernardi

WWU Graduate School Collection

Vedder Mountain lies in Washington state and British Columbia on the western flank of the North Cascades. Metamorphic rocks, which comprise most of the western half of the mountain, can be divided into two separate and distinct units. The southern unit is composed of foliated and non-foliated hornblende-plagioclase gabbro with minor serpentinite and pyroxenite. Most of the gabbroic rocks are sheared and altered and exhibit a lower greenschist facies metamorphism overprinted by a subsequent prehnite-pumpellyite facies metamorphism. Whole-rock chemical analyses of the gabbros plot in and near the fields defined by oceanic gabbro (Engel and Fisher, 1969; Miyashiro et al, …