| Project/Area Number |
62420014
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
地質学一般
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| Research Institution | Kyushu University |
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Principal Investigator |
OGAWA Yujiro Associate Professor Kyushu Univ., 理学部, 助教授 (20060064)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIYAMA Tadao Research Associate Kyushu Univ., 理学部, 助手 (10156127)
NAKADA Setsuya Research Associate Kyushu Univ., 理学部, 助手 (60128056)
HAMAMOTO Reiko Research Assistant Kyushu Univ., 理学部, 教務員 (40089917)
SANO Hiroyoshi Research Associate Kyushi Univ., 理学部, 助手 (80136423)
SAKAI Takashi Research Associate Kyushi Univ., 理学部, 助手 (70128023)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥18,800,000 (Direct Cost: ¥18,800,000)
Fiscal Year 1988: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥16,800,000 (Direct Cost: ¥16,800,000)
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| Keywords | accretionary comples / subduction zone / MORB / hotspot / oceanic crust / 海山 / EDS化学分析 / 前弧域玄武岩 / MORB / ホットスポット起源 |
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| Research Abstract |
We defined the tectonic origin of basaltic rock blocks within several accretionary complex of Permian to Tertiary ages in Southwest Japan based on major and minor element analysis. Basalt chemistry suggests the tectonic settings, ie. within plate basalt of hotspot origin (alkalic or tholeiite), mid-oceanic basalt (MORB)(N-or T-type), and island arc basalt. The field observations, especially the mode of occurrence between the surrounding sediments, the capped limestone or chert, degree of deformation and metamorphism are intimately related to the tectonic settings of those basalts. Basalts which are of MORB are highly deformed and metamorphosed, and capped by bedded chert, indicating the underplated oceanic crust in the deeper levels during oceanic plate subduction, while basalts which are of hotspot origin are weakly deformed and metamorphosed, and capped by reef limestone, indicating the offscraped in the shallower levels or trench collapsed seamount. The former examples are in the Northern Shimanto belt, and the latter examples are in the Akiyoshi, Mino and Konose terranes.
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