Collaborative Research: Elasticity Grand Challenge of the COMPRES Initiative

StixrudeEAR-0135524矿物弹性测量是地球观测到的地震速度结构与地球深部性质(如化学成分和温度)之间的桥梁。矿物物理界准备进行新一代实验，这将使我们能够准确地确定地球深处材料在新的压力和温度(P-T)条件下的性质。我们将进行协调的、多机构的努力，开发先进的实验和理论技术，以确定地球材料上的声速和弹性模数。我们将建立在目前利用光散射和超声波方法的技术基础上，并充分利用同步辐射设施来同时进行表征。我们将寻求利用非弹性x射线散射或千兆赫超声波的新方法来扩展目前的能力。我们将把理论方法和实验紧密结合起来--两者都是事实。利用多种技术，包括理论计算，我们将致力于确定橄榄石及其高压晶型在高P-T条件下的弹性性质，以及用于高P-T校准的标准材料(例如，铂、金、氧化镁、氯化钠)。样品将在中央社区设施中合成。通过实验室间的交叉验证和与理论的比较，每种技术的准确性都将得到提高。这种合作方法将极大地推动高压地球物理技术的发展，并将社区的努力集中在准确确定最重要的地幔阶段的弹性性质上。这些结果将反过来被用来澄清我们对地幔组成和热结构的看法。

StixrudeEAR-0135524Elasticity measurements on minerals are the bridge between the observed seismic velocity structure of the Earth and properties of the Earth at depth, such as chemical composition and temperature. The mineral physics community is poised to undertake a new generation of experiments, which will allow us to accurately determine the properties of deep-Earth materials under a new regime of pressure and temperature (P-T) conditions. We will undertake a coordinated, multi-institutional effort to develop advanced experimental and theoretical techniques for determining sound velocities and elastic moduli on Earth materials. We will build on the current technology that utilizes light scattering and ultrasonic methods and exploit the full use of synchrotron radiation facilities for simultaneous characterization. We will pursue new methodologies utilizing inelastic x-ray scattering or gigahertz ultrasonics to expand the current capabilities. We will closely integrate theoretical approaches with the experimental to ground-truth both. Using multiple techniques, including theoretical calculations, we will focus our efforts on determining the elastic properties of olivine and its high-pressure polymorphs under high P-T conditions, and standard materials for high P-T calibrations (e.g., Pt, Au, MgO, NACI). Samples will be synthesized at a central community facility. The accuracy of each technique will be improved through inter-laboratory cross-checks and comparison with theory. This collaborative approach will greatly advance the technology of high pressure geophysics, and focus a community effort on accurate determination of the elastic properties of the most important mantle phases. These results will, in turn, be used to clarify our view of mantle composition and thermal structure.