1990 Fiscal Year Final Research Report Summary
Petrology, Geochemistry, and Tectonics of Tertiary Igneous Rocks from the Hidaka Belt, Central Hokkaido
| Project/Area Number |
63540605
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
代数学・幾何学
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| Research Institution | Hokkaido University |
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Principal Investigator |
MAEDA Jin'ichirou Hokkaido University, Faculty of Science, Jyosyu, 理学部, 助手 (50165643)
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| Co-Investigator(Kenkyū-buntansha) |
ARITA Kazunori Hokkaido University, Faculty of Science, Lecturer, 理学部, 講師 (30091408)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Hidaka / Hokkaido / NW Pacific / Pankenushi gabbro / Memurodake diorite / Chiroro dolerite / N-MORB / Icelandite |
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| Research Abstract |
Tertiary Hidaka magmatism occurred in a meridional zone extending for about 300 km in Central Hokkaido. The Hidaka magmatism includes tholeiitic layered olivine gabbro, heterogeneous calc-alkaline gabbro-diorite, and I- and S-type granites. Geochemical investigations of the tholeiitic Pankenushi layered gabbroic intrusion, calcalkaline Memurodake heterogeneous pluton, and primitive Chiroro meta-dolerite indicate that they were derived from N-MORB. Therefore Hidaka magmatism is easily explained as normal ridge magmatism intruding into terrigenous sediments. We can assume that the subduction of spreading ridge beneath accretion prism and/or sedimentation of terrigenous sediment on the spreading ridge.
We also found icelanditic rocks from the Hidaka belt. They are not similar in major element composition to the differentiated MORB occurred along the spreading ridge but to the tholeiitic andesite occurred on the hotspot along or near spreading ridge, e. g., andesitic rocks from the Galapagos Islands and Iceland.
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Research Products
(8 results)
