| Abstrakt: |
This study presents evidence that for a solid solution of MgxFex-1SiO3perovskite, the shift in volume thermal expansivity, α, is small as the index χ is changed. According to data obtained theoretically by Hama and Suito (1998), α decreases by 0.3-0.4% as χ changes from 1 to 0.9 in a temperature range of 1900 K. Furthermore, the relative shift in α for Fe substitution is -0.4% under lower mantle conditions. Hama and Suito used the Vinet equation of state to calculate thermoelastic properties. Using a thermodynamic approach applied to the properties of a Debye solid, the data show that the relative shift in a is less than the relative change in specific volume, and, as χ changes from 1 to 0.9, V increases by 0.6% and a decreases by 0.4%. |
