| Project/Area Number |
12304031
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | Tohoku University |
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Principal Investigator |
YOSHIDA Takeyoshi Tohoku University, Graduate School of Sciences, Professor, 大学院・理学研究科, 教授 (80004505)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAHASHI Yoshitaka Fukushima University, Faculty of Education Associate Professor, 教育学部, 助教授 (10292450)
KIMURA Jyunichi Shimane University, Department of Geoscience, Associate Professor, 総合理工学部, 助教授 (30241730)
EHIRO Masayuki Tohoku University, The Tohoku University Museum, Professor, 総合学術博物館, 教授 (10124554)
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| Project Period (FY) |
2000 – 2002
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| Keywords | NE Honshu arc / Crustal structure / Mantle structure / Caldera / Cretaceous granite / laccolith / Seismic velosity structure / Magma plumbing system |
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| Research Abstract |
The chemical compositions of lower crustal and upper mantle derived xenolith from Ichinomegata volcano were analyzed, and the seismic velocities were measured under high pressures. The data was compared with a seismic velocity structure of NE Honshu arc which obtained recently, and obtained a new petrological model of lower crust and upper mantle in NE Honshu arc, Japan.
The results clarified that the average chemical composition of the lower crust is much more basic than estimated before, because they were composed from amphibole gabbro.
The geochemical study of the Quaternary volcanic rocks was showed that there was a possibility of low-K tholeiites were they were composed from partial melts of such amphibole bearing lower crustal materials.
A paper conceming the emplacement model of granitic rocks was submitted now. We have developed a measuring system of composite magnetic fabric of rocks, and applied it to the Goyo granite from Kitakami mountainland. The resulted multiple magnetic fabric reveled by anisotropy of partial anhysteretic remanent magnetization in the Goyo granite represents discrete kinematic events during evolution of the granitic body.
It was clarified by seismic experiments that the magma reservoirs under large-scale collapse calderas show laccolith in its form. The comparison of seismic velocity data and the petrological models of crustal layer have done, and a new evolutional model of crustal structures related magma plumbing system was established and presicely examined in NE Honshu arc, Japan.
Many of the current results of this research were published as full papers, and other new results were submitted by several journals or under the preparation for publish.
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