Sound Velocity of (Mg0.92, Fe0.08)SiO3 Perovskite up to 140 Shock Pressure and its Geophysical Implications

New experimental data of compressional sound velocity VP for natural polycrystalline Enstatite (Mg0.92, Fe0.08) SiO3 initial specimens were measured using the optical analyzer techniques, and our former data were also revised. The VP showed two discontinuities in the pressure range up to 140 GPa. Combination with previous Hugoniot research, three distinct regions appear for (Mg0.92, Fe0.08) SiO3 Enstatite: a low‐pressure phase (LPP, Enstatite) exists up to shock pressures about 64 GPa, while a mixed phase (MP, Enstatite+ Perovskite ) is possible near the high pressure part of this range; perovskite phase (PvP) was found between about 68 to 83 GPa; and then a new high‐pressure perovskite phase (NPvP) occurs at shock pressures higher than 85 GPa. Between 83–85GPa, VP showed a negative jump. The solid to solid microstructure transition of (Mg0.92, Fe0.08)SiO3 Perovskite, caused by the high‐spin to low spin HS‐LS transition of iron around 83 GPa pressure region, probably is responsible for the radial anomaly ...