4:00 PM - 4:15 PM
[PCG22-09] Hugoniot measurements for silicate: Understanding silicate magma under the planetary impacts
In this study, Hugoniot equation of state (EOS) of enstatite has been determined at pressures of ~400 to 560 GPa by laser shock experiments. A coupling of both the present study and the previous data by Fratanduono et al. (2018) shows a discontinuity in the shock velocity-particle velocity at ~380-400 GPa. The measured reflectivity of shocked enstatite indicates three different trends relative to that of quartz; less steep slope at 300-345 GPa, parallel at 345-400 GPa, and a rapid increasing above ~400 GPa, suggesting different phases of enstatite melt, a mixture of metal-like liquid of SiO2and crystalline MgO, and fluid-like enstatite melt above ~380 GPa. We also calculated the release state of thin enstatite using quartz on it as a reference. These results on enstatite imply that reactions in silicate magma occur at pressures of 300-400 GPa and that they may affect the current planet formation model in terms of the stratification of interior, the mantle convection, and the formation of magnetic field in Super-Earths.