1987 Fiscal Year Final Research Report Summary
Petrology and tectonics of Hidaka, Kamuikotan and Tokoto belts in Hokkaido, Japan
| Project/Area Number |
60302031
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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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 | Ehime University (1987)
Niigata University (1985-1986) |
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Principal Investigator |
KOMATSU Masayuki Ehime University, 理学部, 教授 (00018665)
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| Co-Investigator(Kenkyū-buntansha) |
KIMURA Gaku Kagawa University, 教育学部, 助教授 (80153188)
NIIDA Kiyoaki Hokkaido University, 理学部, 講師 (30111149)
TORIUMI Mitsuhiro University of Tokyo, 理学部, 助教授 (10013757)
BANNO Shohei Kyoto Yniversity, 理学部, 教授 (30019468)
ARITA Kazunori Hokkaido University, 理学部, 助手 (30091408)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Hidaka Metamorphic Belt / Kamuikotan tectonic belt / Tokoro belt / high pressure metamorphism / granulite facies / peraluminaous granite / 蛇紋岩メランジ / 北海道 |
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| Research Abstract |
1. A clockwise P-T path of metamorphic rocks was analyses for the Hidaka metamorphic belt, in which 4 deformational-metamorphic stages were defined;(1)tectonic thickning of accretional-forearc sediments metamorphosed under high P/T regime, (2) isobaric heating due to gabbro-diorite magmatism, giving rise to formation of an island arc metamorphic crust, (3)subhorizontal displacement of the crustal layer to form duplex structure, resulting in pressure release, and (4)dextral-reverse movement of the duplex with isobaric cooling.
2. The Kamuikotan high pressure schists were divided into 3 zones using Ca-A1 minerals;I. lawsonite-pumpellyite z.,II. lawsonite-pumpellyite-epidote z.,III. oumpellyite-epidote z. The Schreinemakers analysis of the parageneses show relatively steep P/T gradient in P-T space.
3. Na-amphibole, Na-pyroxene, lawsonite and aragonite were first found in the Tokoro belt, by which the belt was divided into 4 metamorphic zones. The fact supports a thought of two Cretaceous subductions with opposite subduction directions.
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Research Products
(22 results)
