1987 Fiscal Year Final Research Report Summary
The sedimentary and igneous rocks from the Sanbagawa and Chichibu Zones
| Project/Area Number |
61460058
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | The University of Tokushima |
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Principal Investigator |
IWASAKI Masao Prof. Faculty of Inteqrated Arts and Sciences, Tokushima Universtiy, 総合科学部, 教授 (40035291)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Keisuke Ass. Prof., College of General Education, Tokushima Univ., 教養部, 助教授 (20116776)
SUYARI Kazumi Prof., College of General Education, Tokushima Univ., 教養部, 教授 (50035672)
SHIOTA Tsugio Ass. Prof., Faculty of Integrated Arts and Sciences, Tokushima Univ., 総合科学部, 助教授 (90035337)
KAYAMA Tokuichi Ass. Prof., Faculty of Integrated arts and Sciences, Tokushima Univ., 総合科学部, 助教授 (60035334)
KANDA Seiichi Prof. Faculty of Engineering, Tokushima Univ., 工学部, 教授 (00035586)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Sanbagawa Zone / Chichibu Zone / Greenstone / Metamorphic grade / 海溝 / オリストストローム |
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| Research Abstract |
1. Igneous rocks: Concerning to metagabbroic rocks in the Sanbagawa Zone, plagiogranites in the Mikabu Zone and trachytic rocks in the Chichibu Zone, the investigation has been made on their occurrence, mineral composition and geochemistry including the trace element contents. It has been recognized that a part of the igneous rocks from the Sanbagawa and Chichibu Zones belong to the alkaline rock series and all of the igneous rocks from the Mikabu Zone belong to the tholeiitic rock series.
2. Metamorphic grade: In the southern part of eastern Shikoku, Metamorphic grade of the crystalline schists decreases toward to the upper stratigraphic horizon, bowever, it is not clear that whether the grade also decrease or not toward to the same direction as the southern part within the spot-free crystalline schist zone. Investigation on the variation of d-spacing for graphite in pelitic schists has been made, but it was almost impossible to discrimqnate between different metamorphic grades by this method.
3. Sedimentary environment: It has reveald that most of the greenstones in the Sanbagawa, Mikabu and Chichibu Zones belong to the psammitic and pelitic rocks of basic chemical composition or olistoliths in olistostrome. Many ideas have proposed for the explanation on the environment of the sediments, however, clear evidence for this explanation is not yet at hand.
4. Genetical explanation of the igneours rocks in the Sanbagawa and Chichibu Zones are discussed. The metagabbroic rocks in the Sanbagawa Zone seems to be a kind of tectonic blocks which occur in the subducted zone.
The igneous rocks in the Chichibu Zone are derived from the sea mounts in the Paleozoic ocean.
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Research Products
(11 results)
