| Project/Area Number |
07304040
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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 |
Geology
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| Research Institution | Shinshu University |
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Principal Investigator |
HOYANAGI Koichi Department of Science, Shinshu University, Associate Professor, 理学部, 助教授 (30202302)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Hakuyu Department of Science, Kyushu University, Professor, 理学部, 教授 (60037182)
KIMINAMI Kazuo Department of Science, Yamaguchi University, Professor, 理学部, 教授 (20127757)
MASUDA Fujio Department of Science, Kyoto University, Professor, 理学部, 教授 (30091929)
ADACHI Mamoru Department of Science, Nagano University, Professor, 理学部, 教授 (10113094)
KUMON Fujio Department of Science, Shinshu University, Associate Professor, 理学部, 助教授 (60161717)
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| Project Period (FY) |
1995 – 1997
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| Keywords | sandstone / tectonics / East Asia / mobile belt / Basicity Index / provenance / CHIME age / geochemistry |
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| Research Abstract |
The purpose of this project is to know the compositional characteristics of sandstones in the East Asia mobile belt and to clarify their general relationship to the tectonic setting, basin situation, climate and sedimentary environments in mobile belt. Al2O3/SiO2-Basicity Index diagram proposed by Kiminami et al. (1992) and its similar diagrams such as K/Al-(Fe+Mg)/Al diagram have been developed as a tool to know ancient tectonic setting of sedimentary basins. Systematic data of sandstone composition were accumulated for the Permian to Cretaceous in the Japanese Islands. 380 chemical analysis were performed under the control of this project . Heavy mineral assemblage, and chemical composition of detrital minerals such as garnet, spinel, amphibole and plagioclase have been used to detect precise information of source rocks from the key formations of various ages and tectonic setting. Isotope characterization of detrital quartz was tried for the Quaternary sediments of the Kinki district. Abundact and high quality data of sandstones were gathered and accumulated also from Sikhote-Alin, Korea, Philippine, eastern Australia and New Zealand. These data enable to clarify the Circum-Pacific tectonic movement from Paleozoic to Recent. Hydraulic fractionation was checked for turbidites of the Cretaceous Ezo Group and Paleogene Otoanshigawa Group, and concluded that compositional difference controlled by grain size is not serious within sand-size fraction but critical between sand and mud. Hydraulic fractionation is clearly shown on the Al2O3/SiO2-Basicity Index diagram. The compositional variations are also controlled by sedimentary conditions such as sedimentary environments, high stand or low stand of sea-level, and marine transgression or regression. These examples were clarified by this project. These basic researches improve the precise reconstruction of ancient tectonic setting based on sandstone composition.
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