| Project/Area Number |
16340151
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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 |
Geology
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| Research Institution | Shizuoka University |
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Principal Investigator |
MICHIBAYASHI Katsuyoshi Shizuoka University, Faculty of Science, Associate Professor, 理学部, 助教授 (20270978)
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| Co-Investigator(Kenkyū-buntansha) |
LIN Aiming Shizuoka University, Graduate School of Science and Technology, Professor, 創造科学技術大学院, 教授 (90283861)
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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 |
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 2006: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2004: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Keywords | EBSD / peridotite / rheology / 地震 / マントルかんらん岩 / 結晶方位定向性 / マリアナ海溝 / チャレンジャー海淵 / ゼノリス / 静岡大学機器分析センター / 高温高圧変形実験 / マイロナイト / 中央構造線 / 目潟火山 / 高音高圧変形実験 |
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| Research Abstract |
We planned to investigate ultramylonite, which is very-fine grained fault rocks in ductile shear zones, using simultaneous EDS and EBSD in order to determine the phase distribution and the dominant deformation mechanisms. The sample had been analysed previously using both EBSD and light microscopy, but resolution limitations prevented a detailed analysis of the finer grained zones. It was suspected that diffusion creep (atomic migration along grain boundaries) was the dominant mechanism in these zones-this analysis using a FEG-SEM could verify this hypothesis. During this Scientific Research, we established a SEM-EBSD system in Shizuoka University. Although our analyses on ultramylonites are still in progress, we could get some important results on peridotite study.
Seismic anisotropy in the uppermost mantle, back-arc region of the northeast Japan arc : Petrophysical analyses of Ichinomegata peridotite xenoliths
A dense network of seismic stations has been deployed across the northeast Japan arc to investigate mantle wedge structures. To attain independent petrophysical constraints, we determined the seismic properties of Ichinomegata mantle xenoliths from the back-arc region that were brought to the surface from the mantle lithosphere by volcanic eruptions. We calculated the seismic properties of the xenoliths from olivine and pyroxene crystal-preferred orientations and single crystal elastic constants. The small magnitude of measured S-wave splitting (delay time of 0.22 s in the area where the xenoliths were entrained) can be explained by the average seismic properties of mantle xenoliths for an approximately 20-km thick horizontal anisotropic layer, indicating that the mantle lithosphere could be one of the dominant sources of seismic anisotropy; this layer is possibly related to deformation in the uppermost mantle lithosphere due to back-arc spreading along the northeast Japan arc.
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