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GSA Field Trip: Newberry Volcano
From: Julie Donnelly-Nolan (jdnolan@xxxxxxxx)
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Pre-meeting field trip (Oct. 15-17) in conjunction with the annual meeting of the Geological Society of America to be held in Portland, Oregon (Oct. 18-21)
Brief description of trip: Newberry Volcano is located in central Oregon at the intersection of the Cascade Range and the High Lava Plains. Its lavas range in age from about 0.5 Ma to late Holocene. Erupted products range in composition from basalt through rhyolite and cover about 3,000 km2. The most recent caldera-forming eruption occurred about 80,000 yrs ago. This trip will highlight a revised understanding of the volcano’s history based on new detailed geologic work. Stops will also focus on evidence for ice and flooding on the volcano, as well as new studies of Holocene mafic eruptions. Newberry is one of the most accessible U.S. volcanoes and this trip will visit a range of lava types and compositions including tholeiitic and calcalkaline basalt flows, cinder cones, and rhyolitic domes and tuffs. Stops will include early distal basalts as well as the youngest intra-caldera obsidian flow.
Leaders: Julie Donnelly-Nolan (USGS, Menlo Park), Bob Jensen (Forest Service retired), Daniele Mckay (PhD student, U of Oregon), Tim Grove (MIT), Dave Ramsey (Cascades Volcano Observatory)
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