| Project/Area Number |
14540448
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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 |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Nagoya University |
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Principal Investigator |
ENAMI Masaki Nagoya University, Graduate School of Environmental Studies, Professor, 大学院・環境学研究科, 教授 (20168793)
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| Co-Investigator(Kenkyū-buntansha) |
KIMURA Jun-ichi Shimane Univ., Interdisciplinary Faculty of Science and Engineering, Professor, 総合理工学部, 教授 (30241730)
川嵜 智佑 愛媛大学, 理学部, 教授 (50136363)
山本 鋼志 名古屋大学, 大学院・環境学研究科, 助教授 (70183689)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | metamorphism / eclogite / material recycling / metamorphic fluid / subduction zone / garnet-peridotite / Sr-isotope / rock-forming minerals / 珪灰石 / CO2分圧 / P-T経路 / Dissakisite / Hydroxylian pseudorutile |
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| Research Abstract |
The following representative conclusions were drawn from our detailed petrological and mineralogical works on high-pressure and ultrahigh-pressure metamorphic rocks.
(1)Dissakisite is a Mg-derivative substitution of allanite. Cr203-dissakisite occurs in a garnet-lherzolite from the Su-Lu ultrahigh-pressure metamorphic belt, China. This mineral is an important reservoir of Sr and REE hi subducting ultramafic rocks, and plays a significant role in the material interaction between the crust and upper mantle.
(2)Sr-isotopic analyses were done on eclogites and their constituent minerals from the Su-Lu ultrahigh-pressure metamorphic belt, China. The Sr-isotopic zonal structure of zoisite and the estimated 87Sr/86Sr initial ratios clearly indicate widespread metamorphic fluid migration and isotopic homogenization during exhumation stage of the ultrahigh-pressure metamorphic rocks.
(3)Garnet-peridotites from the Bessi area in the Sanbagawa metamorphic belt record the P-T path with early stage of low-temperature hydrous reaction and subsequent stage of nearly adiabatic pressure increase up to 3-4 GPa, showing subduction of wedge mantle peridotites down to 100 km in depth.
(4)The eclogite and non-eclogite units are proposed in the Sanbagawa metamorphic belt mainly based upon the tectonic research. Large pressure gap of 1 GPa at peak metamorphic stage between the two units was confirmed by the phase analyses of chloritoid-bearing metamorphic rocks. This fact clearly indicates the presence of tectonic discontinuity between the two units and petrologically supports the idea of large-scale nappe structure hi the Sanbagawa belt.
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