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Petrogenesis Of The Granitic Rocks Of Part Of The Upper Granite Gorge, Grand Canyon, Arizona, Michael B. Walen
Petrogenesis Of The Granitic Rocks Of Part Of The Upper Granite Gorge, Grand Canyon, Arizona, Michael B. Walen
WWU Graduate School Collection
The study area extends from Phantom Creek to Crystal Creek, a distance of approximately 10 miles along the Colorado River. The units exposed are the Precambrian Vishnu Schist granitic to granodioritic units in Phantom Canyon, Trinity Canyon, and near Crystal Creek, and pegmatites and aplites. The Vishnu Schist is composed mostly of quartzo-feldspathic schists. The assemblage quartz-oligoclase-muscovite-biotite-sillimanite-K-feldspar indicates metamorphic conditions in the upper amphibolite facies between Phantom Creek and Mile 95. Between Mile 95 and Crystal Creek, assemblages indicate lower amphibolite to greenschist facies conditions.
The Phantom Granitic Complex consists of granodioritic and quartz monzonitic units. The presence of a …