| Project/Area Number |
06640578
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Toyama University |
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Principal Investigator |
KUNUGIZA Keitaro Toyama Univ. Faculty of Education, Associate Professor, 教育学部, 助教授 (30225180)
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| Co-Investigator(Kenkyū-buntansha) |
GOTO Atsushi Himeji Institute of Technology, Faculty of Science, Research Assistant, 理学部, 助手 (50211917)
SOHMA Tsuneo Toyama Univ. Faculty of Education, Professor, 教育学部, 教授 (40019039)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1996: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | Hida marginal belt / Geochronology / Crystalline schist / Serpentinite melang / Sangun metamorphic belt / High pressure metamorphic belt / Tectonics / 放射年代 / メランジェ / テクトンクス / 変成岩 / 年代測定 / 高圧型変成作用 / 青海 / カリ長石 / テクトニクス / 飛騨外緑帯 / 構造帯 / 蛇紋岩メランジュ / オリストリス / 高圧変成岩 / 後退変成作用 / 蓮華帯 |
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| Research Abstract |
1. Anatomy of Ohmi serpentinite melange of the Hida merginal belt was discussed. 300Ma schist blocks ocur in association with other types of tectonic blocks including 450Ma garnet amphibolite. Mineral assemblage, mineral chemistry and K-Ar dating of muscovite indicate that the schist blocks in the serpentinite melage were inherited from one crystalline schist belt, and thereafter picked up with serpentinite, remaining essentially their original positions. This occurrence of schist blocks suggests that the uplift of the serpentinite melange took place at some places of extensional field rather than compressional one.
2. We found 450Ma garnet amphibolite block within 300Ma pelitic schist block. Between garnet amphibolite and pelitic schist, there occurs greenschist-like zone including both garnet amphibolite and pelitic schist mineralogy. It is considered that at the time of the extrusion of 300Ma schist blocks, 450Ma garnet amphibolite occuring as hanging wall material of subduction zone was catched up with the pelitic schist, and then suffered mechanical mixing with host pelitic schist.
3. K-Ar muscovite ages from the 21 pelitic schists of the Hida marginal belt indicate that all the pelitic schists in this belt show uniform metamorphic age of 300Ma, irrespective of their wide variation of occurrence ranging from tectonic blocks in serpentinite melange, those in pelitic rock melange and olistolis in the Mesozoic sediment of Tetori group. This uniformity in metamorphic age and the association of Permian accretionary complex suggest that the present-day occurrence of pelitic schists postdated the major process of the uplift of such a high-pressure metamorphic belt. The essential structure of the Hida marginal belt is thus considereed to be the association of Permian accretionary complex and serpentinite melange including 300Ma schist blocks.
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