Experimental study of planetary materials at extreme conditions

D“层位于核幔边界以上200-300公里处，被认为是地球上最神秘的区域之一，是古代大洋板块的潜在墓地，是下地幔与外核之间的缓冲层。因此，D“层具有化学非均质性和热异常的特征。最近发现的后钙钛矿相是钙钛矿相的高压形式，可能是D”层中最丰富的相。因此，了解后钙钛矿相的物理性质和化学成分对于模拟深部地幔对流和地球动力学很重要。在这个方案中，将在下地幔P-T条件下系统地研究含Fe和Al的后钙钛矿相的结构和弹性。在另一项独立但相关的地幔研究中，将使用径向x射线衍射法和晶格强度理论来研究混合地幔相，并在高压和高温条件下提供丰富的新信息。最后，行星材料的电子结构是识别行星内部稳定相的重要关键，有助于理解极端条件下的结构变化，这是至关重要的。为了实现这些目标，将使用高压钻石砧座以及目前正在建立的加拿大第一个定制的高温激光加热钻石砧座系统来进行这些实验研究。这项提议所取得的成果将大大有助于深入了解行星材料的结构，并对地球和其他行星的结构和动力学进行建模。

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.