| Project/Area Number |
16340127
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OKINO Kyoko The University of Tokyo, Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (30313191)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Yasuyuki The University of Tokyo, Ocean Research Institute, Research Assistant, 海洋研究所, 助手 (60345056)
SHINOHARA Masanao The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (90242172)
MOCHIZUKI Kimihiro The University of Tokyo, Earthquake Research Institute, Research Assistant, 地震研究所, 助手 (80292861)
FUJIWARA Toshiya Japan Academy for Marine-Earth and Technology, Institute for Frontier Research on Earth Evolution, Researcher, 地球内部変動研究センター, 研究員 (30359129)
SATO Hiroshi Senshu University, School of Business Administration, Associate Professor, 経営学部, 助教授 (50365847)
小原 泰彦 海上保安庁, 海洋情報部, 主任研究官
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥16,300,000 (Direct Cost: ¥16,300,000)
Fiscal Year 2006: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 2004: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Keywords | crust and mantle material / tectonics / detachment fault / backarc apreading / mid-ocean ridge process / 地球観測 / 海底拡大 / 海洋コアコンプレックス / 国際情報交換 / フィリピン海 / パレスベラ海盆 / ヤップ海溝 |
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| Research Abstract |
The Parece Vela Basin is an extinct backarc basin in the Philippine Sea and has been know as a place where some oceanic core complexes (lower crust and upper mantle material exposure near/on the surface along a large detachment fault) develop. The basin is considered to have formed under magma-starved, tectonic dominant environment. One of the core complexes is the world-largest one and the spreading rate was relatively fast, so it is an important target to understand the magma-starved spreading and the development of detachment faults. The southern part of the basin has not been systematically surveyed and the extent of the core complex distribution and an initial evolutional history of the basin have remained unsolved. During this study, we conducted two geophysical and petrological survey cruises in 2005, and obtained the following results.
1. Another large core complex was found between 13-14°N, where the gabrroic rocks were recovered. Other possible core complexes were also mapped, suggesting the basin-scale, magma-starved spreading occurred in the latest stage of the basin formation.
2. Ultramylonite and mylonite were first reported on the core complex surfaces, suggesting the existence of large detachment fault developing from mantle lithosphere.
3. The structure of the southern tip of the basin was first mapped and a model of early stage of basin formation was proposed. Unique topography indicating robust magmatism was found in the southern tip of the basin, which may be a part of older crust formed before the backarc opening.
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