P-V-T equation of state of MgSiO _3 perovskite based on the MgO pressure scale: A comprehensive reference for mineralogy of the lower mantle

摘要

In situ P-V-T measurements of MgSiO _3 perovskite were carried out up to 110GPa and 2500K, using a sintered-diamond multianvil apparatus and a laser-heated diamond anvil cell together with synchrotron radiation. The P-V-T data sets obtained by multianvil experiments (28-63GPa and 300-1500K) and diamond anvil cell experiments (52-108GPa and 300, 1500-2430K) are consistent with each other. The equation of state of MgSiO _3 perovskite was subsequently represented by a Mie-Grneisen-Debye model, using the equation of state of MgO as reference for pressure determination. In this study, we provide mutually consistent and precise P-V-T equations of state of MgSiO _3 perovskite and MgO applicable to the bottom of the Earth's lower mantle. These P-V-T equations of state and derivative thermodynamic and elastic properties are essential for mineralogy of the lower mantle as a comprehensive reference.