Constraints on the P-V-T equation of state of MgSiO3 perovskite
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Sang-Heon Shim
und
Thomas S. Duffy
Abstract
Equation of state fits to experimental P,V,T data were examined by the inversion of synthetic data sets using the thermoelastic parameters of MgSiO3 perovskite. Our results show that by extending the pressure and temperature range to 130 GPa and 2500 K, the volume dependence of the Grüneisen parameter, q (∂lng/∂lnV), could be resolved to ~10% under the best circumstances. However, simulations also showed strong correlation between the bulk modulus, KT0, and its pressure derivative, K'T0, and q within the currently accepted uncertainty of elastic parameters for MgSiO3 perovskite. We considered the effect of random error based on the reported uncertainty for different measurement techniques. Even though the laser heated diamond-anvil cell (LHDAC) technique has significantly larger temperature uncertainty, the ability to extend the pressure and temperature ranges allows for improved resolution of higher order thermodynamic parameters. However, systematic error from temperature inhomogeneity in the LHDAC sample could result in overestimation of q. We also performed Birch-Murhanghan-Debye (BMD) equation of state (EOS) fits for currently available data sets. Consistent with the simulation results, combining recent LHDAC (Fiquet et al. 1998) and resistance heated diamond-anvil cell (RHDAC) (Saxena et al. 1999) with lower P-T measurements (Ross and Hazen 1989; Wang et al. 1994; Utsumi et al. 1995; Funamori et al. 1996) we obtained q = 2.0(3) and γ0 = 1.42(4). The difference between q = 2.0(3) and the normally assumed value of q =1 strongly affects calculated values for higher order thermoelastic parameters [e.g., a, (∂KT/∂T)P] as well as first order parameters, such as density and bulk modulus at lower mantle conditions. However, possible systematic error sources need to be further investigated and measurements at higher P-T conditions promise to yield better constraints on the thermoelastic parameters of MgSiO3 perovskite
© 2015 by Walter de Gruyter Berlin/Boston
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- Ab initio structure of MgSiO3 ilmenite at high pressure
- Thermoelasticity of silicate perovskites and magnesiowüstite and its implications for the Earth’s lower mantle
- Thermodynamic functions at zero pressure and their relation to equations of state of minerals
- Accuracy of equation-of-state formulations
- Extrapolation of lower mantle properties to zero pressure: Constraints on composition and temperature
- Constraints on the P-V-T equation of state of MgSiO3 perovskite
- Structure analysis and stability field of β-iron at high P and T
- Iron phases at high pressures and temperatures: Phase transition and melting
- Calculated melting curves for phases of iron
- Grüneisen parameter of e-iron up to 300 GPa from in-situ X-ray study
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Artikel in diesem Heft
- Thermal expansivity of mantle relevant magnesium silicates derived from vibrational spectroscopy at high pressure
- Differential laser-interferometer for thermal expansion measurements
- New diamond anvil cells for gigahertz ultrasonic interferometry and X-ray diffraction
- Elasticity measurement of silica glass under gas pressure
- Sound velocities of wadsleyite b-(Mg0.88Fe0.12)2SiO4 to 10 GPa
- Sound velocities and elastic properties of g-Mg2SiO4 to 873 K by Brillouin spectroscopy
- Harmonic and anharmonic properties of spinel MgAl2O4
- The MD simulation of the equation of state of MgO: Application as a pressure calibration standard at high temperature and high pressure
- Ab initio structure of MgSiO3 ilmenite at high pressure
- Thermoelasticity of silicate perovskites and magnesiowüstite and its implications for the Earth’s lower mantle
- Thermodynamic functions at zero pressure and their relation to equations of state of minerals
- Accuracy of equation-of-state formulations
- Extrapolation of lower mantle properties to zero pressure: Constraints on composition and temperature
- Constraints on the P-V-T equation of state of MgSiO3 perovskite
- Structure analysis and stability field of β-iron at high P and T
- Iron phases at high pressures and temperatures: Phase transition and melting
- Calculated melting curves for phases of iron
- Grüneisen parameter of e-iron up to 300 GPa from in-situ X-ray study
- Grüneisen parameters and isothermal equations of state
