Jingui Xu

P-V-T equation of state of Ca3Cr2Si3O12 uvarovite garnet by 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 synthetic uvarovite has been measured at high temperatures up to 900 K and high pressures up to 16.20 GPa, by 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 yielded: V0 = 1736.9 ± 0.5 Å3, K0 = 162 ± 2 GPa, and K′0 = 4.5 ± 0.3. With K′0 fixed to 4.0, we obtained: V0 = 1736.5 ± 0.3 Å3 and K0 = 164 ± 1 GPa. Fitting of our PV- T data by means of the high-temperature third-order Birch-Murnaghan equations of state, given the thermoelastic parameters: V0 = 1736.8 ± 0.8 Å3, K0 = 162 ± 3 GPa, K′0 = 4.3 ± 0.4, (∂K/∂T)P = -0.021 ± 0.004 GPa/K, and α0 = (2.72 ± 0.14)×10-5 K-1. We compared our elastic parameters to the results from the previous studies for uvarovite. From the comparison of these fittings, we propose to constrain the bulk modulus and its pressure derivative to K0 = 162 GPa and K′0 = 4.0-4.5 for uvarovite. Present results were also compared with previous studies for other ugrandite garnets, grossular and andradite, which indicated that the compression mechanism of uvarovite might be similar with grossular and andradite. Furthermore, a systematic relationship, K0 (GPa) = 398.1(7)-0.136(8) V0 (Å3) with a correlation coefficient R2 of 0.9999, has been established based on these isostructural analogs. Combining these results with previous studies for pyralspite garnets-pyrope, almandine, and spessartine-the compositional dependence of the thermoelastic parameters (bulk modulus, thermal expansion, and the temperature derivative of the bulk modulus) were discussed.

Compressional behavior of natural eclogitic zoisite by synchrotron X-ray single-crystal diffraction to 34 GPa

Zoisite is a typical accessory mineral of eclogite; understanding its compressional behavior is important for the knowledge of the properties and processes within subduction zones. In this study, the compressional behavior of a natural eclogitic zoisite Ca1.99(Al2.87Fe0.11)Si3.00O12OH was investigated at ambient temperature and high pressure to 34 GPa, using a diamond anvil cell (DAC) combined with synchrotron-based single-crystal X-ray diffraction (XRD) method. Our results indicate that zoisite is stable over the experimental pressure range. The pressure–volume (P–V) data were fitted to a third-order Birch–Murnaghan equation of state (BM3 EoS), and the equation of state coefficients including zero-pressure unit-cell volume (V0), isothermal bulk modulus (KT0), and its pressure derivative (

Compressibility and equation of state of beryl (Be3Al2Si6O18) by using a diamond anvil cell and in situ synchrotron X-ray diffraction

K_{{T0}}^{\prime }

Equation of state of adamite up to 11 GPa: a synchrotron X-ray diffraction study

KT0′) were obtained as: V0 = 904.77(8) Å3, KT0 = 118(1) GPa, and

P-V-T equation of state of spessartine-almandine solid solution measured using a diamond anvil cell and in situ synchrotron X-ray diffraction

K_{{T0}}^{\prime }

Phase transition and thermoelastic behavior of cadmium sulfide at high pressure and high temperature

KT0′ = 6.3(2), respectively. The axial compressibilities (β) for a-, b-, and c-axes were also obtained using a parameterized form of the BM3 EoS, and the results show βa0 < βb0 < βc0 with βa0:βb0:βc0 = 1:1.28:1.50. In addition, the bulk modulus of this study is very consistent with previously studied zoisite with similar Fe content. However, the axial compressibility is significantly different with the previous study and the compression of zoisite in this study is more isotropic, which may result from the difference in the pressure-transmitting medium.