Contributions to Mineralogy and Petrology

, Volume 52, Issue 2, pp 147–156

The system diopside-ureyite at 20 Kb

  • J. J. Vredevoogd
  • W. C. Forbes

DOI: 10.1007/BF00395011

Cite this article as:
Vredevoogd, J.J. & Forbes, W.C. Contrib. Mineral. Petrol. (1975) 52: 147. doi:10.1007/BF00395011


The join diopside (CaMgSi2O6) — ureyite (NaCrSi2O6) was studied at pressures of 1 atm, 1 kb, 5 kb, and 20 kb using gel mixtures as starting materials. All runs except those at 1 atm were made under hydrous conditions. The data show that the solubility of ureyite in diopside decreases with increasing pressure. At 20 kb the maximum ureyite content of diopside is 13 weight percent (4.6% Cr2O3) as compared to 24 weight percent at 1 atm. It is predicted that pyroxenes that have equilibrated at depths >140 km will not contain a ureyite component; rather Cr will enter diopside in the form of a CaCr(CrSi)O6 component. Pyroxenes containing this component were found as metastable phases at 20 kb.

Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • J. J. Vredevoogd
    • 1
  • W. C. Forbes
    • 1
  1. 1.Department of Geological SciencesUniversity of Illinois at Chicago CircleChicago

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