Basaltic volcanism of the central and western Snake River Plain:: A guide to field relations between Twin Falls and Mountain Home, Idaho
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Published:January 01, 2005
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CiteCitation
John W. Shervais, John D. Kauffman, Virginia S. Gillerman, Kurt L. Othberg, Scott K. Vetter, Ruth Hobson V., Meghan Zarnetske, Matthew F. Cooke, Scott H. Matthews, Barry B. Hanan, 2005. "Basaltic volcanism of the central and western Snake River Plain:: A guide to field relations between Twin Falls and Mountain Home, Idaho", Interior Western United States, Carol M. Dehler
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Abstract
Basaltic volcanism in the Snake River Plain of southern Idaho has long been associated with the concept of a mantle plume that was overridden by North America during the Neogene and now resides beneath the Yellowstone plateau. This concept is consistent with the time-transgressive nature of rhyolite volcanism in the plain, but the history of basaltic volcanism is more complex. In the eastern Snake River Plain, basalts erupted after the end of major silicic volcanism. The basalts typically erupt from small shield volcanoes that cover up to 680 km2 and may form elongate flows that extend 50–60 km from the central vent. The shields coalesce to form extensive plains of basalt that mantle the entire width of the plain, with the thickest accumulations of basalt forming an axial high along the length of the plain. In contrast, basaltic volcanism in the western Snake River Plain formed in two episodes: the first (ca. 7–9 Ma) immediately following the eruption of rhyolites lavas now exposed along the margins of the plain, and the second forming in the Pleistocene (≤2 Ma), long after active volcanism ceased in the adjacent eastern Snake River Plain. Pleistocene basalts of the western Snake River Plain are intercalated with, or overlie, lacustrine sediments of Pliocene-Pleistocene Lake Idaho, which filled the western Snake River Plain graben after the end of the first episode of basaltic volcanism. The contrast in occurrence and chemistry of basalt in the eastern and western plains suggest the interpretation of volcanism in the Snake River Plain is more nuanced than simple models proposed to date.
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Contents
Interior Western United States

The GSA Annual Meeting in Salt Lake City provided a large and diverse terrain for field trips—from the Basin and Range to the Rocky Mountains, from the Snake River Plain, across the Colorado Plateau, to the Mojave Desert. This volume contains 22 field trip articles, nearly all of those run at the 2005 meeting. All combine the latest research with useful road logs to spectacular and often classic geologic settings. The regional tour has a core of structure and stratigraphy-paleontology contributions, and is rounded off with volcanic, glacial, lacustrine, fluvial geomorphology, neotectonic, geologic hazard, and geoarchaeology articles.
GeoRef
- basalts
- Basin and Range Province
- Cenozoic
- Elmore County Idaho
- eruptions
- field trips
- ground water
- hydrology
- Idaho
- igneous rocks
- lava flows
- mantle
- mantle plumes
- Neogene
- North America
- Quaternary
- rhyolites
- road log
- shield volcanoes
- siliceous composition
- Snake River plain
- surface water
- Tertiary
- Twin Falls County Idaho
- United States
- volcanic rocks
- volcanism
- volcanoes
- Twin Falls Idaho
- Mountain Home Idaho