Thermoelastic parameters for six minerals at high temperature

Abstract

The complete high‐temperature data for six minerals measured in the University of California, Los Angeles, Mineral Physics Laboratory are analyzed and presented as a group. These minerals include CaO and a calcium rich garnet, grossular. We find no significant differences in the thermoelastic parameters for the calcium rich minerals when compared with the calcium deficient minerals. Evidence of anharmonicity is shown in the specific heat, C V , of corundum, forsterite, pyrope, and grossular garnet, but no evidence is found for the case of MgO and CaO. The patterns for the thermoelastic parameter γ show that in general γ decreases with temperature T and that γ at constant volume always decreases rather markedly with T . The thermoelastic parameters, δ T , δ S , and α K T tend to remain independent of T at high T (above Θ), whereas they are not independent of T near room temperature. The thermal pressure at P = 0 is quite linear with T at temperatures above Θ for all six minerals. We find no evidence of anharmonic behavoir for the thermoelastic parameters of forsterite, correcting an earlier report by Anderson and Suzuki (1983) that anharmonicity appeared in γ, δ T ;, δ S , and α K T at high T for this mineral.