1991 Fiscal Year Final Research Report Summary
Geologic development of Japan in the Pacific context
| Project/Area Number |
02302029
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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 |
地質学一般
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| Research Institution | Shizuoka University |
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Principal Investigator |
TUCHI Ryuichi Shizuoka University, Faculty of Science, Professor, 理学部, 教授 (60021929)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Niichi Nara University, Fact. Social Sci., Asist. Prof., 社会学部, 助教授 (00207789)
ARAMAKI Shigeo Hokkaido University, Fact, Sci., Professor, 理学部, 教授 (60012895)
MIZUTANI Shinjiro Nagoya University, Fact. Sci., Professor, 理学部, 教授 (50022538)
ICHIKAWA Koichiro Osaka University of Industry, Professor, 教授 (70046738)
KURODA Yoshimasu Shinsyu University, Fact, Sci., Professor, 理学部, 教授 (20015530)
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| Project Period (FY) |
1990 – 1991
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| Keywords | IGCP / Asian continent / Island arc / Sea of Japan / Shield / Accretion / Diatomite / Tectonic landform |
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| Research Abstract |
The purpose of the research is to summarize the geologic development of Japan in the Pacific context based upon the recent advancement of geological sciences. This is also the contribution of Japanese working group to the International Geological Correlation Program (IGCP) during 1991 and 1992.
Prior to the opening of the Sea of Japan in Neogene time, Japan was situated in the continental margin of the eastern Asia, where it was formed through a stepwise process of accretions 1) took place contemporaneously with major configuration of the ancient Asian continent, 2) happened during Jurassic-earhest Cretaceous times being correlative with a regional one from Sichote-Alin to Palawan in the Pan-Pacific context, and 3) took place during late Cretaceous-early Cenozoic times. Characters of granitic rocks of the island are are, however, quite different from those of the shield in view of the presence or absence of water containing. Studies on continental fragments in the Japanese Islands, restoring the Gondwana continent, and analyses of sedimentary petrological data are in progress.
The opening of the Sea of Japan and the Japanese island arc were established at 15 Ma in the middle Neogene. However, the island arc had been pulled apart from the Asian continent around 16 Ma, when the Mid-Neogene marine climatic optimum was prevailed in Japan and the Pacific, and major tectonic disturbances seem to took place in the SE Asia and the SE Pacific. Following climatic deteriorations made the development of the Antarctic ice sheet and caused coastal water upwelling in the East Pacific and the diatomaceous deposition in many places. Quaternary tectonic landforms are well examined along the coast of the Japanese islands.
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