The study will involve diamond-anvil experiments coupled with laser heating, spectrographic, and synchrotron x-ray diffraction techniques to determine phase equilibrium in the mantle and core of the earth. Combination of high-pressure and synchrotron techniques provides the opportunity to improve current earth models significantly by providing experimental data on mineralogical and geochemical relations of the entire mantle-core system. It is proposed to build on current experimental results obtained at conditions equivalent to those of the transition zone to study in situ reversible phase relations. The second part of the study is to examine concepts of major element partitioning over the extensive pressure-temperature range of the lower mantle. The third part of the study will be an experimental examination of the core mantle boundary by determining the equilibrium (or the lack of equilibrium) between silicate-oxide-metal assemblages. The fourth part of the study will be a determination of the phase equilibria of core compositions.
