Thermoelastic Equation of State of Monoclinic Pyroxene : CaMgSi_2O_6 Diopside
Access this Article
Search this Article
We have conducted an in situ synchrotron x-ray diffraction study on a monoclinic pyroxene: CaMgSi<SUB>2</SUB>O<SUB>6</SUB> diopside at simultaneous high pressures and high temperatures up to 8. 2 GPa and 1280 K. A modified Rietveld profile refinement program has been applied to refine the diffraction spectra of low symmetry and multiple phases observed in energy dispersive mode. Thermoelastic parameters for diopside CaMgSi<SUB>2</SUB>O<SUB>6</SUB> are derived by fitting the P-V-T data to the high-T Birch-Murnaghan equation of state. We obtained isothermal bulk modulus K<SUB>TO</SUB> =109. 1 GPa with a pressure derivative of bulk modulus K'=∂K/∂P=4. 84, temperature derivative of bulk modulus K=∂K/∂T=-2. 05×10<SUP>-2</SUP> GPa/K, volumetric thermal expansivity α=a+ bT with values of a=2. 32×10<SUP>-5</SUP>K<SUP>-1</SUP> and b=1. 88×10<SUP>-8</SUP>K<SUP>-2</SUP>.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 25-27, 1998
The Japan Society of High Pressure Science and Technology