Experimental Determination of the Thermal Equations of State of Mantle and Core Materials

EAR-0309486下地幔和地核的几个组分的状态方程将在高压和温度下确定。要研究的化合物包括(Fe，Ni)合金、(Mg，Fe)O系列、(Mg，Fe)SiO_3-钙钛矿、Fe3C和FeS。单位晶胞体积和其他结晶学信息将使用同步加速器x射线衍射法获得，同时样品在金刚石顶压室中进行压缩和激光加热。将在状态方程测量过程中检测和识别固相线下的相变。压力校准将使用内部标准。这些实验的实验方法论已经在阿贡国家实验室的高级光子源被证明是成功的。要收集的数据不仅对于理解地震学数据至关重要，因为地震学数据显示了地球内部密度和弹性的变化，而且对于开发地球化学演化模型也是至关重要的。拟议研究的结果将主要通过在科学文献上发表、参加科学会议以及在必要时通过更广泛的新闻机构传播。拟议研究的其他好处包括继续开发和改进实验高压高温技术；大学研究人员，包括学生参与者，继续接触政府资助的多用户场地的设施和人才；对学生进行与开展拟议工作有关的各种实验技术和科学规程方面的培训。

EAR-0309486The equations of state of several constituents of the lower mantle and core will be determined at high pressures and temperatures. The compounds to be studied include (Fe,Ni) alloy, the (Mg,Fe)O series, (Mg,Fe)SiO3-perovskite, Fe3C, and FeS. Unit cell volumes and other crystallographic information are to be obtained using synchrotron x-ray diffraction while the samples are compressed and laser-heated in a diamond anvil cell. Subsolidus phase transitions will be detected and identified during the course of the equation of state measurements. Internal standards will be used for pressure calibration. The experimental methodology for these experiments has been proven successful at the Advanced Photon Source, Argonne National Laboratory. The data to be collected are critical not only to understand the seismological data, which show variations in density and elasticity within the Earth, but also for developing models of chemical evolution of the Earth. Results from the proposed study will be disseminated primarily through publication in the scientific literature, by participation at scientific conferences, and when warranted, through wider-reaching news outlets. Additional benefits of the proposed research include the continued development and refinement of experimental high-pressure, high-temperature techniques; continued exposure of university researchers, including student participants, to the facilities and talent at government-funded multi-user sites; and the training of students in the wide range of experimental techniques and scientific protocols associated with performing the proposed work.