Ellis, David E. and Wyllie, Peter J. (1979) A model of phase relations in the system MgO-SiO_2-H_2O-CO_2 and prediction of the compositions of liquids coexisting with forsterite and enstatite. In: Kimberlites, diatremes, and diamonds: their geology, petrology, and geochemistry. Vol.1. American Geophysical Union , Washington, DC, pp. 313-318. https://resolver.caltech.edu/CaltechAUTHORS:20160406-131055238
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Abstract
A comprehensive model has been developed for the system MgO-SiO_2-H_2O-CO_2 on the basis of experimental studies, Schreinemaker's rules, and thermodynamic data. The assemblage forsterite plus enstatite is predicted to melt in the presence of vapor of any H_2O/CO_2 ratio at low pressures, in the presence of vapor whose H_2O/CO_2 ratio is buffered by the presence of magnesite at intermediate pressures, and at a vapor-absent eutectic with brucite and magnetite at high pressures. The composition of the liquid at the solidus for a bulk composition of forsterite plus enstatite plus a small amount of volatiles with a 3/1 H_2O/CO_2 ratio changes from enstatite-quartz normative at 20 kbar, to periclase- forsterite normative at 50 kbar, to forsterite-enstatite normative at 90 kbar and greater pressures. Forsterite cannot coexist with H_2O-CO_2 vapor at pressures greater than 90 kbar. Thus all melting in the earth's mantle at higher pressures must be vapor-absent.
Item Type: | Book Section | ||||
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Alternate Title: | A model of phase relations in the system MgO-SiO2-H2O-CO2 and prediction of the compositions of liquids coexisting with forsterite and enstatite | ||||
Additional Information: | © 1979 American Geophysical Union. This research was supported by the Earth Sciences Section, National Science Foundation, NSF Grant EAR 76-20410. | ||||
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Record Number: | CaltechAUTHORS:20160406-131055238 | ||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20160406-131055238 | ||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||
ID Code: | 65968 | ||||
Collection: | CaltechAUTHORS | ||||
Deposited By: | Tony Diaz | ||||
Deposited On: | 06 Apr 2016 21:47 | ||||
Last Modified: | 03 Oct 2019 09:52 |
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