Hugoniot equation of state and sound velocity of CaSiO3 glass under shock compression

TL;DR

This study investigates the shock compression behavior of CaSiO3 glass, revealing phase transformations, deriving its equation of state and sound velocity, and providing insights into the melting temperature of davemaoite in the Earth's lower mantle.

Contribution

It provides the first experimental data on the Hugoniot equation of state and sound velocity of CaSiO3 glass under shock compression, and insights into phase transformations relevant to Earth's mantle.

Findings

CaSiO3 glass transforms into crystalline phase above 34 GPa

Complete transformation into davemaoite occurs above 120 GPa

No melting observed up to 117.6 GPa, suggesting higher melting temperature for davemaoite

Abstract

Davemaoite, as the third most abundant mineral in the lower mantle, constitutes significant amounts in pyrolite and mid-ocean ridge basalts. Due to its unquenchable nature, measurements by static compression techniques on physical properties of davemaoite at lower mantle conditions are rare and technically challenging, and those are essential to constrain compositions and properties of mineralogical models in the lower mantle. Here, we present Hugoniot equation of state and sound velocity of CaSiO3 glass under shock compression. The CaSiO3 glass transforms into the crystalline phase above 34 GPa and completely transforms into davemaoite above 120 GPa. Thermal equation of state and Hugoniot temperature of davemaoite have been derived from the shock wave data. The CaSiO3 glass under shcok compression has very high shock temperature. Shock wave experiments for sound velocity of CaSiO3 glass indicate that no melting is observed at Hugoniot pressure up to 117.6 GPa. We propose that the melting temperature of davemaoite should be higher than those reported theoretically by now.