Paleomagnetic stratigraphy, geochemistry and source areas of Miocene ash-flow tuffs and lavas of the Badger Mountain area, northwestern Nevada
AuthorPark, Steven Lynn
Geological Sciences & Engineering
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The tuffs of Badger Mountain and Alkall Flat, middle Miocene ash-flow tuffs of northwestern Nevada, are distinguished from the lithologically similar Soldier Meadow Tuff by their lover iron content, leaser cathodolumiscence of sanidine phenocrysts and, for the tuff of Badger Mountain, reversed polarity of thermoremanent magnetization (TRM). Identical TRM directions of the tuff of Alkali Flat and Soldier Meadow Tuff suggest simultaneous eruptions from separate vent areas. Coincident gravity and magnetic anomalies within the Badger Mountain area may reflect a buried caldera (Greene and Plouff. 1981), but the uniform thickness and continuity of the tuffs of Badger Mountain and Alkali Flat preclude their association with it. If present, this buried caldera may be related to the eruption of the Summit Lake Tuff. Porphyritic rhyolite lavas near Devaney Mountain, dated at 14.2 + 0.3 m.y ., exhibit petrologic and chemical evidence of the mixing of dacitic and high-silica rhyolitic magmas.
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