| Project/Area Number |
17540439
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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 | Waseda University |
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Principal Investigator |
TAKAGI Hideo Waseda University, Faculty of Education and Integrated Arts and Sciences, Professor (60154754)
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| Co-Investigator(Kenkyū-buntansha) |
ENJOJI Mamoru Waseda University, Faculty of Education and Integrated Arts and Sciences, Professor (70015890)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,680,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | healed microcrack / sealed microcrack / paleostress field / Ryoke Granite / collision of the Izu arc / Tanzawa Tonalite / Median Tectonic Line / 伊豆弧の衝突 / 古応力場 / 領家花崗岩 |
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| Research Abstract |
To estimate the influence of the bending of the Median Tectonic Line(MTL) by the late Miocene collision of the Izu-Ogasawara arc, we examined the 3-D orientations of healed microcracks in the Ryoke granitic rocks and the Tanzawa Tonalite and determined the paleostress field. The results are as follows :
1. δHmax directions recorded as the orientation of healed microcracks from the Nojima Granodiorite(Awaji Island), Misugi Tonalite(Mie Pref.) and Shinshiro Tonalite(Aichi Pref.)are nearly parallel to the current strike of the MTL. These results suggest that the microcrack-bearing granitic bodies along the MTL are rotated together with the MTL during the arc-arc collision. However, those from the Takato Granite(Nagano Pref.) are almost normal to that of the MTL. It is not able to be explained by the bending, and open to research more.
2. δHmax directions recorded as the orientation of both healed and sealed microcracks from the Tanzawa Tonalite which was collided at c. 5Ma are fairly constant throughout the body(NNE-SSW). Geothermometry on fluid inclusions constituting healed microcracks suggest that the formation of them was occurred at the condition of 300〜400℃. This trend was explained by the divergent δHmax trajectories at the northeastern side of colliding center which has the movement direction of NW.
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