Redetermination of high-temperature heat capacity of Mg₂SiO₄ ringwoodite

Abstract

It is widely accepted that (Mg,Fe)₂SiO₄ ringwoodite is a major constituent mineral in the mantle transition zone. High-temperature heat capacity data of Mg₂SiO₄ ringwoodite measured by previous studies are not consistent with those by theoretical calculations. In this study, it was remeasured by the differential scanning calorimetry in the temperature range of 300-850 K. The present heat capacity shows 3%-5% larger value than those observed by the previous studies. Re-examination of the thermodynamic stability of Mg₂SiO₄ ringwoodite at high pressures and high temperatures will be needed.