| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Kenji Yamaguchi Univ., Dept.Educ., Assoc.Proff., 教育学部, 助教授 (50155008)
MIYAMOTO Tkami ditto, ditto, Asst. Proff., 理学部, 講師 (00090548)
WATANABE Makoto ditto, ditto, Assoc. Proff., 理学部, 助教授 (80033900)
SAKURAI Yasuhiro ditto, ditto, ditto, 理学部, 助手 (80205814)
HAYASAKA Yasutaka ditto, ditto, Res. Assoc., 理学部, 助手 (10198830)
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| Research Abstract |
Study on movement victbres of Japanese tectonic collage is focused in this research project on the basis of analysis of microtextures of rocks and minerals under microscope and transmission electron microscope(JEM- 2000ES) and P-T-t-D paths in its constituent metamorphic belt, which are based on analysis of chemical composition of metamordhic minerals by electron probe microanalyser and of radiometric ages. The studied metamorphic belts are Hida belt, Sangun belt, Ryoke belt, Sambagawa belt, Abukuma belt and Hidaka belt. Especially, the research progress in the Sambagawa belt, Ryoke belt, Hida belt and Hidaka belt appears to be noteworthy. In the Unazuki subbelt of the Hida belt have been analyzed the tectonic history, igneous history, ages of igneous rocks and deformation styles related to igneous activity. It has been clarified that the Jurassic granitic rocks intruded into a great fracture zone during the formation process of the nappe of the Hida belt. In the Ryoke belt have been a
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nalyzed movement picture of mylonitization of the Ryoke older granitic rocks and their deformation styles with special reference to deformation styles of quartz and feldspar. It has been pointed out that the origin of ultramylonites is ascribed to microfracturing of plagioclase and K-feldspar and to recrystallization of fractured materials. In the Hidaka belt have been analyzed the tectonic history, igneous history and movement pictures and deformation style of rocks related to the igneous activity. It has been clarified that the ianeous intrusions occurred in fractured zones and that the first stage magma was derived from a subducted ridge (probably Kula-Pacific ridge) and the second stage magma was of calc-alkaline type. In the Sambagawa belt have been in great details analyzed the geological structure, thermal structure of the highest-temperature phase, tectono-metamorphic processes, movement pictures of individual deformation phases and deformation styles of rocks and minerals during individual deformation phases, clarifying P-T-t-D path. The obtained results are considered to be considerablly available for understanding of the uplifting process of the high-pressure type metamorphic rocks. Less
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