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Oxygen-isotope geochemistry of quaternary rhyolite from the Mineral Mountains, Utah, USA

Technical Report ·
DOI:https://doi.org/10.2172/5350286· OSTI ID:5350286

Oxygen isotope analyses were made of phenocryst and glass separates from four Quaternary rhyolite flows and domes in the Mineral Mountains, southwest Utah. With the exception of biotite in all samples and alkali feldspar in the rhyolite domes, all minerals appear to be in close oxygen isotope exchange equilibrium. The geothermometry equations proposed by Bottinga and Javoy (1973) and Javoy (1977) for quartz, alkali feldspar and magnetite produce the best agreement with temperature results fom two-feldspar and iron-titanium oxide geothermometry for these rhyolites. If the rhyolites were generated by partial melting in the crust, their whole-rock (glass) delta/sup 18/O values (6.3 to 6.9 permil) are consistent with generation from I-type (Chappell and White, 1974, O'Neil and Chappell, 1977; O'Neil et. al., 1977) sources.

Research Organization:
Utah Univ., Salt Lake City (USA). Dept. of Geology and Geophysics
DOE Contract Number:
AC07-79ID12079
OSTI ID:
5350286
Report Number(s):
DOE/ID/12079-61; ON: DE82019951
Country of Publication:
United States
Language:
English