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Stratigraphic And Geochemical Evolution Of The Glass Buttes Complex, Oregon, Richard Louis Roche
Stratigraphic And Geochemical Evolution Of The Glass Buttes Complex, Oregon, Richard Louis Roche
Dissertations and Theses
Glass Buttes complex lies at the northern margin of the Basin and Range province in central Oregon and is cut by the northwest-trending Brothers fault zone. An older acrystalline volcanic sequence of high-silica rhyolites (>75% SiO2) forms a broad platform composed of domes and flows with minor pyroclastic deposits. The high-silica rhyolite sequence is divided on the basis of texture into 1) zoned flows and domes, 2) obsidian flows, 3) felsite flows, and 4) biotite-phyric flows and domes.