Element partitioning at ultrahigh pressure and chemical evolution of the Earth's interi

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In this work, we determined the partition coefficients of lithophile and siderophile elements between Mg-perovskite and magma, Mg-perovskite and molten iron, magma and molten iron, and magnesiowustite and molten iron. The experiments of the partitioning between molten iron and magma indicate that the partition coefficients between magma and molten iron implies that those for Fe, Co, and Ni decrease with increasing pressure, whereas that of Mn increase with increasing pressure, and these partition coefficients increases with increasing temperature. We also studied the effect of sulfur and carbon for the partitioning between magma and molten iron. We found that the partition coefficients of Mo and W,especially W,change with existence of a small amount of sulfur in the system ; W (and Mo) n the sulfur containing system tends to enter into the silicate magma compared to those in sulfur free system. The present partitioning behavior of Mo and W implies that the present mantle abundance of W and Mo is consistent with the core-mantle equilibrium without sulfur in the system. This suggests that sulfur is not likely to be a candidate for the light element in the core.We also conducted the melting and phase transition experiments of the mantle minerals, such as the Mg_2SiO_4-Fe_2SiO_4, Mg_2SiO_4-Mg_3Al_2Si_3O_<12>, and Mg_2SiO_4-H_2O systems. These data provide basic information on the deep seated magmatism and the amount of water in the transition zone and the upper most part of the lower mantle.