2004 Fiscal Year Final Research Report Summary
Elements circulation within the earth deduced from the mineralogical and petrological studies of eclogites
| 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)
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| Project Period (FY) |
2002 – 2004
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| Keywords | metamorphism / eclogite / material recycling / metamorphic fluid / subduction zone / garnet-peridotite / Sr-isotope / rock-forming minerals |
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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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Research Products
(33 results)
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[Journal Article] Petrological constraints on the formation conditions and retrograde P-T path of the Kotsu eclogite unit, central Shikoku2003
Author(s)
Matsumoto, M., Wallis, S.R., Aoya, M., Enami, M., Kawano, J., Seto, Y.
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Journal Title
Journal of Metamorphic Geology 21
Pages: 363-376
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Petrological constraints on the formation conditions and retrograde P-T path of the Kotsu eclogite unit, central Shikoku.2003
Author(s)
Matsumoto, M., Wallis, S., Aoya, M., Enami, M., Kawano, J., Seto, Y., Shimobayashi, N.
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Journal Title
Journal of Metamorphic Geology 21
Pages: 363-376
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Chemical diversity of the Ueno Basalts, central Japan ; identification of mantle and crustal contributions to arc basalts2002
Author(s)
Kimura, J.-I., Manton, W.I., Sun, C.H., Iizumi, S., Yoshida, T., Stern, R.J.
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Journal Title
Journal of Petrology 43
Pages: 1923-1946
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Chemical diversity of the Ueno Basalts, central Japan ; identification of mantle and cruslal contributions to arc basalts.2002
Author(s)
Kimura, J.-L, Manton, W.I., Sun, C.H., Iizumi, S., Yoshida, T., Stem, R.J.
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Journal Title
Journal of Petrology 43
Pages: 1923-1946
Description
「研究成果報告書概要(欧文)」より
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