Experimental study of planetary materials at extreme conditions

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The D" layer is located at 200-300 km above core-mantle boundary and is regarded as one of the most mysterious regions in the Earth. The D" layer is a potential graveyard of ancient oceanic plates and the buffer layer between lower mantle and outer core. Hence, the D" layer is characterized by chemical heterogeneity and thermal anomalies. The recently discovered post-perovskite phase is the high-pressure form of perovskite phase and may be the most abundant phase within the D" layer. Therefore, knowledge of the physical properties and chemical compositions of the post-perovskite phase is important to model deep mantle convection and dynamics of the Earth. In this proposal, the structure and elasticity of Fe- and Al-bearing post-perovskite phase will be systematically examined at lower mantle P-T conditions. In a separate but related mantle study, the radial x-ray diffraction method, together with lattice strength theory, will be employed to study mixed mantle phases and to provide a wealth of new information under high-pressure and high temperature conditions. Finally, the electronic structures of planetary materials are an important key to identify the stable phases in planetary interiors and help to understand the structural variations under extreme condition, which is fundamentally important. To achieve those goals the high-pressure diamond-anvil cell, together with the first custom-built high-temperature laser-heating diamond-anvil cell system in Canada which is currently being set up, will be used for these experimental investigations. The results obtained in this proposal will be of great help in providing insights into the structure of planetary materials and to model the structure and dynamics of the Earth and other planets.