Thermal expansivity of mantle relevant magnesium silicates derived from vibrational spectroscopy at high pressure
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Anastasia Chopelas
Abstract
Thermal expansivities for the MgSiO3 phases of orthoenstatite, high clinoenstatite, ilmenite, and majorite; and for stishovite were estimated using the thermodynamic Maxwell relation (∂S/∂P)T = -(∂V/∂T)P where the entropies at high pressures were derived using a statistical method and spectroscopic data. The spectroscopically determined thermal expansivities for all minerals are in excellent agreement with previously determined volumetric data, where available. A value of 3.25(10) × 10-5K-1 for orthoenstatite at room temperature was obtained; this value is situated in the middle of the large spread of reported values and is in excellent agreement with the two latest volumetric determinations. For high clinoenstatite, α at room T is estimated as 2.56(9) × 10-5K-1. This method provides good high temperature estimates of α for the high-pressure polymorphs, where data are scanty or unavailable. Included in this report are previous data for the Mg2SiO4 phases and MgO for completeness. The following equations may be used to extrapolate a to higher temperatures at 1 atm in 10-5K-1: a(majorite) = 2.95 + 0.000521x; α(γ-Mg2SiO4) = 2.70 + 0.000648x; α(ilmenite) = 2.64+ 0.000537x; α(perovskite) = 2.51 + 0.000805x; and α(stishovite) = 2.19 + 0.000485x, where x is (T/K-750)
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- 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
Articles in the same Issue
- 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
