P- V- T equation of state of spessartine-almandine solid solution measured using a diamond anvil cell and in situ synchrotron X-ray diffraction
Abstract
The pressure-volume-temperature ( P- V- T) equation of state (EoS) of two natural garnet samples along spessartine-almandine (Spe-Alm) join has been measured at high temperature up to 800 K and high pressures up to 15.46 and 16.17 GPa for Spe64Alm36 and Spe38Alm62, respectively, using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P- V data to a third-order Birch-Murnaghan EoS yields: V 0 = 1,544.4 ± 0.4 Å3, K 0 = 180 ± 3 GPa and = 4.0 ± 0.4 for Spe38Alm62, and V 0 = 1,557.5 ± 0.3 Å3, K 0 = 176 ± 2 GPa and = 4.0 ± 0.3 for Spe64Alm36. Fitting of our P- V- T data by means of the high-temperature third-order Birch-Murnaghan EoS gives the thermoelastic parameters: V 0 = 1,544.6 ± 0.6 Å3, K 0 = 180 ± 4 GPa, = 4.0 ± 0.4, (∂ K/∂ T) P = -0.028 ± 0.005 GPa K-1 and α 0 = (3.16 ± 0.14) × 10-5 K-1 for Spe38Alm62, and V 0 = 1,557.7 ± 0.9 Å3, K 0 = 176 ± 4 GPa, = 4.0 ± 0.5, (∂ K/∂ T) P = -0.029 ± 0.005 GPa K-1 and α 0 = (3.04 ± 0.16) × 10-5 K-1 for Spe64Alm36. The results confirm that almandine content increases the bulk modulus of the spessartine-almandine join following a nearly ideal mixing model. The relation between bulk modulus and almandine mole fraction ( X Alm) in this garnet join is derived to be K 0(GPa) = 171.6(±2.6) + 10.9(±1.8) X Alm. Present results are also compared with previously studies determined the thermoelastic properties of other garnets.
- Publication:
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Physics and Chemistry of Minerals
- Pub Date:
- January 2015
- DOI:
- 10.1007/s00269-014-0700-2
- Bibcode:
- 2015PCM....42...63F
- Keywords:
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- Spessartine-almandine solid solution;
- Equation of state;
- High pressure and high temperature;
- X-ray diffraction;
- Diamond anvil cell