| Project/Area Number |
62540593
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
OGASAWARA Kenshiro (1988) Institute of Geology and Paleontology, Fac. Sci., Tohoku Univ., 理学部, 助教授 (20110653)
小高 民夫 (1987) 東北大学, 理学部, 教授 (70004257)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMORI Toru Institute of Geology and Paleontology, Fac. Sci., Tohoku Univ., 理学部, 助手 (00192229)
MORI Kei Institute of Geology and Paleontology, Fac. Sci., Tohoku Univ., 理学部, 教授 (00004466)
KOTAKA Tamio Institute of Geology and Paleontology, Fac. Sci., Tohoku Univ., 理学部・東北大学, 名誉教授 (70004257)
小笠原 憲四郎 東北大学, 理学部, 助手 (20110653)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Cenozoic / Shallow-water fauna / Geohistory / Tethys / Endemism / Zoogeography / Paleogeography / (3)この暖海域の拡大は日本列島の古地理と、植物化石から推定された古気候的な背景から支持され、群集に地理的差異が生じた。 / (4)台湾・八重山地域の独自性は地理的勾配でなく、古地理的な影響により生じた可能性が高い。 / (5)中期中新世以降の日本固有種の形成は日本列島の古地理的背景に加えて、約5℃の平均気温の低下に対応して成立していった。 / 以上のような予察を踏まえ将来は本邦とテチス浅海域間で系統的な姉妹種を具体的にみい出し、平行進化的立場からの検討を加える必要があると考えられる。 / 新生代 / 底生動物群集 / 地史的変遷 / テチス海 / 固有種 / 生物地理 / 古地理 / 古気候 / 浅海動物群 / 中生代 / 古海洋事件 / 浅海底生動物群 / 古生物地理 / 古水深指標 |
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| Research Abstract |
The Japanese Cenozoic shallow-water faunas have been considered to a representative of the Indo-West Pacific element which was originated in the shallow Tethys regions. However, recent studies suggested that there are some East-Pacific element in the Japanese Cenozoic. The present study is a trial to consider the geohistorical proccess of birth of the Japanese Cenozoic shallow-water faunas from a zoogeographic oint of view. The following outlines are summerized mainly based on comparative studies on shallow-water elements between the Japanese and Tethys regions;
1. Related genera and species between the two regions are recognizable during the Mesozoic
2. There are some elements in common between the two at the Paleogene although data is insufficient
3. At the early Middle Miocene, there are some common warm-water elements in the area from Java, Philippines through Southwest Japan to southern Hokkaido
4. After the early Middle Miocene, there is no element in common between the two
5. At the early Middle Miocene, there are some. characteristic elements restricted in the Taiwan-Yaeyama region
These tentative conclusions from paleozoogeographic point of view are examined from the paleogeographic, paleoceanographic and paleoclimatic studies. Consequently, it can be said that the proto-Kuroshio Current first appeared at the early Miocene corresponding to form a zoogeographic barrier between the Indian and Westerm Pacific oceans. Such paleogeographic and paleoceanographic backgrounds maight be permitted a wide invasion of Miocene warm-water elements to the North, Succeed this event, faunal endemism of the Late Miocene Japanese shallow-water fauna maight be progressed corresponding to cooling event of about 5 ゜C mean temparature decrease which is estimated by paleobotanical studies.
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