Renewal-Experimental Studies of Elasticity, Rheology, Volume, and Texture of Materials at Pressure-Temperature Conditions of the Earth's Mantle and Core

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。对地幔和地核的地球物理观测为我们提供了大量尚未完全理解的大规模过程和现象。构成深层内部大部分的矿物受到巨大的压力和温度的影响，这些压力和温度极大地改变了矿物的性质。该合同将支持研究人员将实验室模拟的压力-温度能力扩展到内核的极端条件。他们将开发新技术，利用国家x射线设备来调查压缩矿物的变化特性，并将使用新的数据来帮助解释地球物理观测结果。拟议中的实验还将阐明在地球形成过程中，液态铁核是如何从岩石地幔中分离出来的。除了使用团队在先前支持下开发的新可用同步加速器分析探针电池继续采集外核P-T范围内的数据外，他们还建议将矿物物理研究扩展到内核P-T条件（330-360 GPa, 5000-6000 K），并实现亚微米单晶的弹性和变形测量，非晶体材料的直接体积测定，以及对岩石复杂粒间结构的研究。这些新功能将通过钻石砧细胞与最先进的纳米聚焦硬x射线束的集成，3D x射线断层扫描与全视野纳米物镜，以及由NSF-MRI资助的新一代激光加热系统来实现。利用新的和现有的技术，研究人员建议沿着地热P-T条件研究地幔硅酸盐、氧化物和硫化物、核心金属和合金的弹性、流变学、体积和结构。这些结果将用于解决主要的地球物理问题，包括岩浆海洋之外的地幔-核分离，地幔中硅酸盐和氧化物晶界中液态铁的排水或捕获，流体的质量运输，地幔和核心深处的地震剖面和异常，外核中铁和合金的液体密度，内核矿物学，生长和流变学，以及提出的最内层内核的性质。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Geophysical observations of the Earth's mantle and core present us with a rich array of large-scale processes and phenomena that are not yet fully understood. Minerals that make up the bulk of the deep interior are subject to enormous pressures and temperatures that drastically altered the minerals properties. This award will support the investigators to extend their pressure-temperature capability of in-laboratory simulations to the extreme conditions of the inner core. They will develop new techniques using national x-ray facilities to investigate the altered properties of the compressed minerals, and will use the new data to help interpreting the geophysical observations. The proposed experiments will also shed light on how the liquid iron core separated from the rocky mantle during the Earth's formation.In addition to the continuation of data acquisition up to the P-T range of the outer core using a battery of newly available synchrotron analytical probes that the team has developed with prior support, they propose to extend mineral physics investigations to inner core P-T conditions (330-360 GPa, 5000-6000 K), and to enable elasticity and deformation measurements of sub-micron single crystals, direct volume determinations of non-crystalline materials, and investigations of complex intergranular textures of rocks. These new capabilities will be accomplished by integration of diamond-anvil cells with the state-of-the-art nano-focusing hard x-ray beam, 3D x-ray tomography with full-field nanoscope objective, and a new-generation, laser-heating system supported by a NSF-MRI grant. Using the new and existing techniques, the investigators propose to study elasticity, rheology, volume, and texture of the mantle silicates, oxides, and sulfides, and core metals and alloys along the geotherm P-T conditions. The results will be used to address major geophysical issues, including mantle-core separation beyond the magma ocean, drainage or trapping of liquid iron from silicate and oxide grain boundaries in the mantle, mass transport of fluids, seismic profiles and anomalies in the deep mantle and core, liquid density of Fe and alloys in the outer core, inner core mineralogy, growth, and rheology, and nature of the proposed innermost inner core.