Thermal Equations of State of Mantle Minerals

硅酸盐钙钛矿和镁橄榄石是地球下地幔的两个主要相态。它们的热状态方程的精确确定对于制约下地幔的化学成分和矿物学研究具有重要意义。PI将建立适用于下地幔P-T条件的地幔钙钛矿和镁橄榄石的热状态方程，方法是：（1）在外部加热的金刚石单元中进行高达136 GPa和1000 K的静态压缩实验，以及（2）在多砧装置中进行高达28 GPa和2400 K的静态压缩实验。实验数据将直接与地震数据导出的地幔密度剖面进行比较，以评估下地幔是否与橄榄岩地幔模型一致。拟议的研究是PI通过实验和热力学模拟来了解下地幔化学和矿物学的持续努力的一个组成部分。这项研究的综合方法将大大提高我们获得与地球内部直接相关的P-T条件的能力，这将对高压研究产生广泛的影响。该项目将为博士后研究员提供获得高压研究经验的机会。拟议研究的结果将主要通过在科学期刊上发表文章、参加科学会议以及在必要时通过公共新闻媒体进行传播。预期结果将在地球物理、矿物物理、地球化学和地球动力学等领域产生广泛影响。

Silicate perovskite and magnesiowustite are the two dominant phases of the Earth's lower mantle. Accurate determinations of their thermal equations of state are of great importance for constraining the chemical composition and mineralogy of the lower mantle. The PI will establish thermal equations of state of mantle perovskite and magnesiowustite that are applicable to the P-T conditions of the lower mantle by performing (1) static compression experiments in the externally-heated diamond cell up to 136 GPa and 1000 K, and (2) static compression experiments in the multi-anvil apparatus up to 28 GPa and 2400 K. The experimental data will be directly compared with mantle density profile derived from seismic data to evaluate if the lower mantle is consistent with the peridotitic mantle model.The proposed research is an integral part of the PI's continuous efforts to understand the chemistry and mineralogy of the lower mantle through experimentation and thermodynamic modeling. The integrated approach in this research will greatly improve our ability to access the P-T conditions directly relevant to the Earth's interior that will have broad impact on high-pressure research. The project will provide opportunity for postdoctoral fellows to gain research experience in high-pressure research. Results from the proposed study will be disseminated primary through publications in scientific journals, by participation at scientific conferences, and when necessary, through public news media. The expected results will have broad impact in many different fields including geophysics, mineral physics, geochemistry, and geodynamics.