Study on the material cycle through accretionary prism, boundary between ocean and continent

在四国、纪伊半岛、中部和关东的高压型变质带的典型实例--三钵川变质带中进行了地质和地质构造研究，并在那里采集了岩石学和年代学研究所需的岩石样品。通过对高压型变质岩的背散射电子像观察和成分矿物的EDS分析，揭示了高压型变质岩的P-T轨迹。利用X射线衍射仪和质谱仪分析了沉积岩中的碳质和有机质的晶体结构。对产于纪伊半岛的桑巴川片岩中的白云母精矿进行了~（40）Ar/~（39）Ar定年，并记录了75-77 Ma的高原年龄。根据本课题的研究成果，讨论了增生棱柱体及相关地区的沉积变质演化，并着重讨论了物质循环。

Research of geology and geologic structure has been done in the Sambagawa metamorphic belt, as a typical example of high-pressure type metamorphic belt, in Shikoku, Kii Peninsula, Chubu and Kanto, and rock samples for petrological and geochronological studies have been collected there. Observation of backscattered electron images and chemical analyzes of constituent minerals by the EDS,and P-T paths of the high-pressure type metamorphic rocks have been revealed. Crystal structure of carbonaceous and organic matters within the sedimentary rocks, which were derived from shallow portions of accretionary prism, were analyzed by using X-ray diffraction meter and mass spectrometer. 40Ar/39Ar dating for muscovite concentrates obtained from the Sambagawa schists in Kii Peninsula, and well-defined plateau ages of 75-77 Ma are recorded in the muscovite concentrates. According to the results obtained from this research project the sedimentation and metamorphic evolution in accretionary prism and related areas have been discussed with special reference to the material cycle.