Late Cenozoic basalts from the Basin-Range province, western United States

dc.contributor.advisorRogers, John J. W.en_US
dc.creatorLeeman, William Prescotten_US
dc.date.accessioned2016-04-22T21:59:10Zen_US
dc.date.available2016-04-22T21:59:10Zen_US
dc.date.issued1969en_US
dc.description.abstractPetrographic and chemical analyses demonstrate that late Cenozoic mafic lavas from the Basin-Range province, western United States, are predominantly alkali-olivine basalts. Associated with these lavas are lesser volumes of basaltic andesite which appear to be differentiates from the more primitive alkali basalts. Late Cenozoic basalts from adjacent regions (Columbia River Plateau, Snake River Plain, Yellowstone area, High Cascades and Sierra Nevada) are predominantly tholeiitic. This apparent petrologic provincialism is supported by complementary variations in heat flow, seismic velocities, crustal thickness, magnetic anomalies and geologic setting. Alkali-olivine basalts from Japan and eastern Australia are analogous to those from the Basin-Range province both in composition and tectonic environment. It is suggested that these lavas are the products of a unique environment characterized by high heat flow and a thin crust. Recent melting experiments on peridotites and basalts and measurements of heat flow allow limits to be placed on the depth of origin of Basin-Range alkali-olivine basalt magmas. It is proposed that these lavas are produced by partial melting (less than 20%) of peridotitic mantle material at depths between 40 and 60 km in response to an elevated geothermal gradient. The basaltic andesites may be derived from hydrous alkali basalt magma by fractionation at depths of 30 to 40 km.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent88 ppen_US
dc.identifier.callnoThesis Geol. 1969 Leemanen_US
dc.identifier.citationLeeman, William Prescott. "Late Cenozoic basalts from the Basin-Range province, western United States." (1969) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/89961">https://hdl.handle.net/1911/89961</a>.en_US
dc.identifier.digitalRICE0996en_US
dc.identifier.urihttps://hdl.handle.net/1911/89961en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.titleLate Cenozoic basalts from the Basin-Range province, western United Statesen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentEarth Scienceen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Artsen_US
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