| Project/Area Number |
59390023
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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 |
広領域
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| Research Institution | Tokyo Metropolitan University, Faculty of Science |
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Principal Investigator |
MACHIDA Hiroshi Professor, Tokyo Metropolitan Univ., 理学部, 教授 (10087009)
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| Co-Investigator(Kenkyū-buntansha) |
KITAZATO Hiroshi Lecturer, Shizuoka Univ., 理学部, 講師 (00115445)
OHBA Tadamichi Professor, Kanazawa Univ., 教養部, 教授 (60013588)
OHTA Yoko Professor, Yokohama national Univ., 教育学部, 教授 (80017714)
OOMURA Akio Associate Professor, Kanazawa Univ., 理学部, 助教授 (70019488)
ARAI Fusao Professor, Gunma Univ., 教育学部, 教授 (80008119)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1984: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | Widespread tephra / Late Quaternary / Explosive volcanism / Age determination / The last interglacial age / Marine terrace / Tectonic movement / 深海底堆積物編年 |
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| Research Abstract |
1 In this research project eleven major volcanic ashes of the Late Quaternary age are reported in and around Japan. All of them are characterized and identified by petographic and stratigraphical methods. They are of great significance in volcanology as well as Quaternary research. The widespread vitric fine-grained ashes which originated from gigantic caldera volcanoes are all interpreted as coignimbrite ash falls. This type of tephra should be the dominant class of widespread tephra.
2 Chemical composition of volcanic glass shards analysed by EPMA proved to be a powerful tool in characterization and identification of submarine volcanic ashes around the Japanese islands.
3 The ages of four marker tephras occurring in central Honshu are estimated by the <^(230)Th> / <^(238)U> method based on the <^(230)Th> - <^(238)U> radioactive disequilibrium observed in the mafic minerals of the tephras.
4 Determinations of marker tephras in northern Japan and southern Kyushu are favorable for correlation and identification of marine terraces of the last interglacial age, resulting in revision of the chronological framework and recognition of the tectonic nature of these regions.
5 Vertical changes in oxygen isotope values of the planktonic and benthic foraminiferal tests of the two tephrochronologically dated cores from the northwestern Pacific are reported, resulting in establishment of the standard sequence of deepsea sediment chronology around Japan.
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