Collaborative Research: Elasticity Grand Challenge of the COMPRES Initiative

矿物的弹性测量是观测到的地球的地震速度结构和地球的深度属性（如化学成分和温度）之间的桥梁。矿物物理学界正准备进行新一代的实验，这将使我们能够准确地确定在新的压力和温度（P-T）条件下地球深部材料的特性。我们将采取协调的、多机构的努力，发展先进的实验和理论技术，以确定地球材料的声速和弹性模量。我们将在现有技术的基础上，利用光散射和超声波方法，充分利用同步辐射设备进行同步表征。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，以扩大目前的能力。我们将把理论方法与实验方法紧密结合起来，使两者都成为事实。使用多种技术，包括理论计算，我们将集中努力确定橄榄石及其高压多晶体在高P-T条件下的弹性特性，以及高P-T校准的标准材料（例如Pt， Au, MgO， NACI）。样品将在社区中心设施合成。每个技术的准确性将通过实验室间的交叉检查和与理论的比较来提高。这种合作方法将极大地推进高压地球物理技术，并将社区的努力集中在准确确定最重要的地幔相的弹性特性上。这些结果将反过来用于澄清我们对地幔组成和热结构的看法。

Bass0135642Elasticity 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.