Ultrasonic Velocity Measurements on Multiphase Agg

地球深部地幔的化学成分为地表的许多过程提供了重要信息，包括全球碳收支和水循环、地震和板块构造。由于没有深度超过12公里的样品可用于直接的实验室调查，该团队的方法是将候选岩石和矿物样本带回实验室设备内的深部地幔压力和温度条件下，然后进行现场实验，以了解这些矿物在地幔深度的物理和化学状态和性质。与以前的研究相比，这个项目标志着一个重大的进步，它直接测量合成岩石样本中的声速，这些岩石样本与真实地球的声速更接近。从技术和科学两方面来看，这些技术进步可以很容易地应用于非地球科学物质的研究，例如那些对工业和能源科学以及设计和发现新材料很重要的物质。pi建议使用超声干涉测量法结合同步加速器x射线辐射，对下地幔顶部的多相火成岩组成和地幔组成矿物（KLB-1辉石岩；粘石和辉石）的压缩[P]和剪切[S]波速和密度进行直接测量，直至P- t条件。这些直接测量的聚集体速度考虑了平衡试样中共存相（相分数，小元素分配）之间化学反应的影响以及小元素对弹性的影响，可以直接与地震速度-深度剖面进行比较。除了得到作为深度函数的火成岩成分模型的相平衡外，这些前所未有的结果将为解释地震衍生的速度和密度随深度剖面提供关键数据，并对地球内部的矿物成分和动态过程进行限制。

The chemical composition of the Earth's deep mantle holds important information for many processes at the surface, including the global carbon budget and water cycles, earthquakes, and plate tectonics. Since no samples from depths greater than 12 km are available for direct laboratory investigations, the team's approach is to bring candidate rock and mineral specimens back to the deep mantle pressure and temperature conditions inside a laboratory apparatus, and then conduct in-situ experiments to understand the physical and chemical states and properties of these minerals at mantle depths. In comparison with previous studies, this project marks a major advancement by measuring directly the sound velocities in synthetic rock samples which bear a closer resemblance to those in the real Earth. From both technological and scientific aspects, these technological advances can be readily applied to the study of non-geoscience substances, such as those important to industrial and energy sciences and for the designing and discovery of new materials.The PIs propose to conduct direct measurements of compressional [P] and shear [S] wave velocities and densities on multi-phase aggregates of pyrolitic composition and mantle constituent minerals (KLB-1 pyroxenes; coesite and stishovite) up to the P-T conditions of the top of the lower mantle using ultrasonic interferometry in conjunction with synchrotron X-radiation. These directly measured velocities of aggregates take into account the effects of chemical reactions among co-existing phases (phase fractions, minor element partitioning) in the equilibrated specimens as well as the effect of minor elements on elasticity and can be compared directly with seismic velocity-depth profiles. In addition to yielding phase equilibria for pyrolitic compositional model as a function of depth, these unprecedented results will provide critical data for the interpretation of seismically-derived velocity and density vs. depth profiles and place constraints on the mineralogical composition and dynamic processes of the Earth's interior.