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.
