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Molten (Mg0.88Fe0.12)2SiO4 at lower mantle conditions - Melting products and structure of quenched glassesInfrared spectra of quenched magnesium silicate glasses synthesized by fusing olivine at pressures in excess of 50 GPa and temperatures greater than 2500 K demonstrate that silicon is dominantly present in four-fold coordination with respect to oxygen within these quenched glasses. This low coordination is attributed, by analogy with the structural behavior of glasses compressed at 300 K, to the instability of higher coordinations in glasses of these compositions on decompression. Spectra of glasses formed in a hydrous environment document that water is extensively soluble in melts at these high pressures and temperatures. Also, these results are consistent with the melting of (Mg0.88Fe0.12)2SiO4 compositions to liquids near pyroxene in stoichiometry under these conditions, with iron-rich magnesiowuestite being the liquidus phase.
Document ID
19900043990
Document Type
Reprint (Version printed in journal)
Authors
Williams, Quentin (California, University Santa Cruz, United States)
Date Acquired
August 14, 2013
Publication Date
April 1, 1990
Publication Information
Publication: Geophysical Research Letters
Volume: 17
ISSN: 0094-8276
Subject Category
GEOPHYSICS
Distribution Limits
Public
Copyright
Other