Stability and equation of state of the post-perovskite phase in MgGeO3 to 2 Mbar
Abstract
The stability and equation of state of the post-perovskite phase in MgGeO3 were investigated to 2 Mbar by in situ x-ray diffraction experiments using the laser-heated diamond cell as well as by theoretical calculations using density functional theory. The stability of the phase was demonstrated at 92-201 GPa during laser heating. By using the Birch-Murnaghan equation of state, we obtained a zero-pressure volume (V0) of 179.2 +/- 0.7 Å3, bulk modulus (K0) of 207 +/- 5 GPa with a pressure derivative (K'0) of 4.4 from experiments at room temperatures, and V0 = 178.02 Å3, K0 = 201.9 GPa, K'0 = 4.34 from theoretical calculations at 0 K. The relative axial compressibilities of the silicate and germanate post-perovskite phases are similar although MgSiO3 is more anisotropic than MgGeO3.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- May 2006
- DOI:
- 10.1029/2006GL025686
- Bibcode:
- 2006GeoRL..3312S12K
- Keywords:
-
- Mineralogy and Petrology: Mineral and crystal chemistry (1042);
- Mineralogy and Petrology: Experimental mineralogy and petrology;
- Mineral Physics: Equations of state;
- Mineral Physics: High-pressure behavior;
- Mineral Physics: X-ray;
- neutron;
- and electron spectroscopy and diffraction