Collaborative Research: Experimental Determination of Trace Element Distributions between Melts and Mantle Phases at P, T and X Relevant to MORB Genesis

建议的项目是继续提供三年经费，研究在非常接近洋中脊下部分地幔熔融和洋中脊玄武岩成因期间存在的温度、压力和成分的情况下，地幔相和熔体之间的耦合相平衡和微量元素分配。 这项工作将建立在以前的结果，确定矿物熔体分配在二辉橄榄岩地幔成分在1.2和3.4 Gpa之间的压力。 晶体液体分配系数将确定稀土元素（REE），Hf，Zr，Nb，U，Th和Ba使用离子微探针。 将准备尽可能接近橄榄岩固相线的分析装药，以最接近部分地幔熔融的条件。 在这项工作中，橄榄岩实验电荷形成的压力高达5.0 Gpa将进行检查，包括在较低的压力下的新研究。 还将分析代表1.0-3.0 Gpa压力的辉石岩费用，以形成关键数据集，从而允许测试假设MORB和羽流熔体来源中的石榴石辉石岩（或榴辉岩）的模型。 还将分析贫化橄榄岩（harzburgite）装药。 这些新数据将被纳入新的地幔熔融综合模型，该模型将主要元素和微量元素的组成结合起来。

Recommended project is for three years of continued funding of research on coupled phase equilibria and trace element partitioning between mantle phases and melt at temperatures, pressures and compositions which closely approximate those which exist under mid-ocean ridges during partial mantle melting and mid-ocean ridge basalt (MORB) genesis. This work will build upon previous results that determined mineral-melt partitioning at for lherzolite mantle compositions at pressures between 1.2 and 3.4 Gpa. Crystal liquid partition coefficients will be determined for the rare earth elements (REE), Hf, Zr, Nb, U, Th, and Ba using an ion microprobe. Analytical charges will be prepared that are as close as possible to the peridotite solidus to most closely approximate conditions of partial mantle melting. In this work peridotite experimental charges formed at pressures up to 5.0 Gpa will be examined, including new studies at lower pressures. Pyroxenite charges representing pressures of 1.0-3.0 Gpa will also be analyzed, to form critical datasets that will allow the testing of models hypothesizing garnet pyroxenite (or eclogite) in the source of both MORB and plume melts. Depleted peridotite (harzburgite) charges will also be analyzed. These new data will be incorporated into new integrated models of mantle melting that integrate both major and trace element compositions.***