title: An Occurrence of Metastable Cristobalite in High-Pressure Garnet Granulite
abstract: High-pressure (0.8 gigapascals) granulite facies garnet from Gore Mountain, New York, hosts multiple solid inclusions containing the low-pressure silica polymorph cristobalite along with albite and minor ilmenite. Identification of cristobalite is based on Raman spectra, electron microprobe analysis, and microthermometric measurements on the alpha/beta phase transformation. The cristobalite plus albite inclusions may have originated as small, trapped samples of hydrous sodium-aluminum-siliceous melt. Diffusive loss of water from these inclusions under isothermal, isochoric conditions may have resulted in a large enough internal pressure decrease to promote the metastable crystallization of cristobalite.
authors.affiliation: R. S. Darling, Department of Geology, State University of New York College at Cortland, Cortland, NY 13045, USA. I.-M. Chou, U.S. Geological Survey, 955 National Center, Reston, VA 20192, USA. R. J. Bodnar, Department of Geological Sciences, 4044 Derring Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.initials: RS
authors.lastname: Darling
authors.initials: IM
authors.lastname: Chou
authors.initials: RJ
authors.lastname: Bodnar