Heat capacity of MgSiO3 perovskite

Heat capacity of MgSiO3 perovskite has been measured in the temperature range 140–295 K by differential scanning calorimetry. The Kieffer model approach has been used to calculate the heat capacity beyond the measured temperature range. The estimated entropy of MgSiO3 perovskite is 57.2±1.0 J/mol.K at 298 K which is higher than that of ilmenite, in accord with the negative pressure‐temperature slope for the ilmenite‐perovskite transition. From the heat capacity thermodynamic Debye temperature of MgSiO3 perovskite is evaluated to be 980±15 K at 298 K and 1030±20 K at temperatures above about 700 K. Thermodynamic Gruneisen parameter of MgSiO3 perovskite at 30 GPa and above 1000 K is also estimated as 1.45±0.15. An adiabatic temperature profile in the pyrolitic lower mantle is calculated with the average gradient of 0.32±0.04 K/km. The temperature at the top of the D″ layer is estimated to be 2500±100 K.