The solubility of alumina in enstatite and the phase equilibria in the join MgSiO3-MgAl2SiO6 at 10 25 kbar
Abstract
The solubility of alumina in enstatite was determined in the range of 1100 1500° C and 10 25 kbar. The alumina content in enstatite coexisting with sapphirine and quartz increases with increasing temperature and pressure, while that in enstatite coexisting with sapphirine and sillimanite or with pyrope decreases with increasing pressure and decreasing temperature. Two univariant lines, pyrope = enstatitess + sillimanite + sapphiriness and enstatitess + sillimanite =sapphiriness + quartz were confirmed. The invariant point involving these phases is metastable. The alumina content of orthopyroxene can not be used either as a pressure indicator or as a temperature indicator without taking the mineral assemblage into account.
- Publication:
-
Contributions to Mineralogy and Petrology
- Pub Date:
- January 1977
- DOI:
- 10.1007/BF00376700
- Bibcode:
- 1977CoMP...61..251A