U.S.-Japan Cooperative Research: Study of Melt-Solid Segregation in the Upper Mantle as Represented by the Horoman Peridotite, Hokkaido, Japan

该奖项将促进地球科学合作 Frederick A.弗雷和清水伸道， 地球、大气和行星科学系， 马萨诸塞州理工学院，以及Masaaki教授 日本熊本大学地质学系的小幡和 几位日本同事。 科学家们将合作 在对霍罗曼橄榄岩的研究中， 位于日本北海道的一种岩层。 这是一 不寻常的形成，来自地球的上地幔， 其特征在于发育良好的层结构， 矿物成分的系统变化和暴露良好 相对没有地壳蚀变的岩石。 这些特性使其成为研究某些地球化学的理想材料 在上地幔发生的过程，特别是 部分熔体的形成、偏析和迁移。 观察到的分层被解释为反映了 部分熔融的上升地幔中的“岩浆波”。 的 因此，霍罗曼可能实际上是一块上地幔， 熔体形成和偏析过程被冻结 在原地。 合作的科学家们将联合收割机 橄榄岩建造的野外和岩石学研究， 常量和微量元素丰度的地球化学分析 以及岩石中的放射性同位素比值。 层状上地幔岩石的研究是重要的，因为它 提供了有关部分熔化和熔体偏析的信息 发生在地球的上地幔。 虽然很差 理解，这些过程似乎是根本的 地球的过去、现在和未来的演化。 这 对霍罗曼橄榄岩的研究旨在 更好地理解这些过程。

This award will facilitate cooperation in earth science between Professors Frederick A. Frey and Nobumichi Shimizu, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, and Professor Masaaki Obata, Department of Geology, Kumamoto University, Japan, and several Japanese colleagues. The scientists will collaborate in a study of the Horoman peridotite, a large, exposed igneous rock formation on the Japanese island of Hokkaido. It is an unusual formation, derived from the earth's upper mantle, and characterized by a well developed layer structure, with systematic changes in mineral composition and well-exposed rocks which are relatively free from crustal alteration. These properties make it ideal for studying certain geochemical processes that have occurred in the upper mantle, particularly the formation, segregation and migration of partial melts. The observed layering has been interpreted as reflecting "magma waves" in a partially molten, ascending mantle. The Horoman may thus actually be a piece of upper mantle where the processes of melt formation and segregation have been frozen in situ. The cooperating scientists will combine a quantitative field and petrologic study of the peridotite formation with geochemical analyses for major and trace element abundances and radiogenic isotope ratios in the rocks. A study of layered upper mantle rocks is important because it provides information on the partial melting and melt segregation occurring in the earth's upper mantle. Though poorly understood, these processes appear to be fundamental to the past, current, and future evolution of the earth. This investigation of the Horoman peridotite is aimed at contributing to a better understanding of these processes.