1988 Fiscal Year Final Research Report Summary
Paleozoogeographical study of Cenozoic molluscan fauna in Japan
| Project/Area Number |
62540601
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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 |
Stratigraphy/Paleontology
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| Research Institution | Nagoya University |
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Principal Investigator |
ITOIGAWA Junji School of Science, Nagoya University, 理学部, 教授 (90022566)
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| Co-Investigator(Kenkyū-buntansha) |
UJIHARA Astushi College of General Education, Nagoya University, 教養部, 助手 (50193868)
SHIBATA Hiroshi College of General Education, Nagoya University, 教養部, 教授 (50022603)
MORI Shinobu School of Science, Nagoya University, 理学部, 助手 (00089856)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Paleozoogeography / Molluscan fossil / Fossil assemblage / Oligocene / Miocene / Pliocene / 新生代 |
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| Research Abstract |
1. Distribution of tropical molluscan assemblages in Middle Miocene is analyzed. The assemblages consist of mangrove swamp elements and others. They distribute from south to Niigata-Yamagata area and are typical in Yatsuo, Toyama and Bihoku, Okayama-Hiroshima. Similar temperature condition is seen beween present Iriomote and Middle Miocene Toyama.
2. In Southwest Japan, two faunas, the lower, the Akeyo and the upper, the Kurosedani faunas, are recognized in the early to middle miocene. The ages of the two faunas ale 18 to 16 Ma and 16 to 15 Ma, respectively. The Kurosedani includes typical tropical element spement species of molluscs. The Akeyo which consists of subtropical elements differs from the Kurosedani lacking Tropical species. tropical, subtropical and temperate paleozoogeographical divisions are recognized in Middle Miocene of the Jananese Islands.
3. Molluscan faunas of the Kakegawa and Ogasa groups are studied. Remarkable change from the sublittoral fauna in northwest to the bathyal one in southwest is recognized. Temporal change of species and assemblages indicates Grade I, II and III changes of Itoigawa(1988).
4. The idea of grade in molluscan fauna distribution in time and space shown by Itoigawa(1988) is checked. Molluscan faunas of Oligocene and Miocane in various localities are compared and the grade is clearly recognized.
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Research Products
(13 results)
