Stability of high-density clinoenstatite at upper-mantle pressures
Abstract
In the absence of experimental data, orthoenstatite was long believed to be the stable polymorph of (Mg, Fe)-pyroxene over the entire upper mantle. More recently, however, petrological experiments at pressures and temperatures in excess of 8 GPa and 900 C have provided evidence for the transformation of Mg-orthopyroxene to a clinopyroxene phase. The results of a high-pressure single-crystal diffraction study are reported which confirm the stability of a high-clinopyroxene phase of MgSiO3 at high pressures. The findings allow an initial estimate to be made of the density changes associated with the transformation of the orthopyroxene component in the earth's upper mantle.
- Publication:
-
Nature
- Pub Date:
- July 1992
- DOI:
- 10.1038/358322a0
- Bibcode:
- 1992Natur.358..322A
- Keywords:
-
- Earth Mantle;
- Phase Stability (Materials);
- Pyroxenes;
- Silicates;
- Density Distribution;
- Physical Properties;
- Single Crystals;
- Thermodynamic Properties;
- Geophysics