CaltechAUTHORS
  A Caltech Library Service

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

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

[img] PDF - Published Version
See Usage Policy.

1945Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20160406-131055238

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
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.
Funders:
Funding AgencyGrant Number
NSFEAR 76-20410
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

Repository Staff Only: item control page