Chemical reaction between silicate and iron under high pressure and temperature

Abstract

Chemical reaction between silicate and iron at high pressures and high temperatures was investigated, simulating the present core-mantle boundary and the core formation process in the early history of the Earth. Starting materials were synthetic pyrope garnet and MORB glass for the mantle material, and pure iron for the core material. High pressure and high temperature experiments were performed using laser heated diamond anvil cell up to about 60 GPa and above the melting point of pure iron. The temperature quenched samples were examined by in situ X-ray diffraction method at BL-13A, Photon Factory, KEK. The identified phases after heating for several dozens of minuets were basically consistent with the results in the literature and no extra phase was observed below the melting point of iron. However, a couple of samples treated above the melting point of iron indicate a possibility of the decomposition reaction of silicate phase. These observaions suggest a possible dissolution of silicon to the core.