1999 Fiscal Year Final Research Report Summary
Origin and route of the Neogene deep sea molluscan fauna in Ryukyu Islands
| Project/Area Number |
09839006
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
自然史科学
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| Research Institution | University of Tsukuba, Institute of Geoscience |
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Principal Investigator |
NODA Hiroshi Institute of Geoscience, University of Tsukuba Professor, 地球科学系, 教授 (00004341)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAGATA Shungo Institute of Geoscience, University of Tsukuba Research Associate, 地球科学系, 助手 (70302354)
KIKUCHI Yoshibumi Institute of Geoscience, University of Tsukuba Research Associate, 地球科学系, 助手 (00241787)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Okinawa / Neogene / Pliocene / Deep sea / Mollusca / Echinoid fossils / Benthic foraminifers / Shinzato Formation |
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| Research Abstract |
The stratigraphy and paleontology of the Neogene and Quarternary deposits in Okinawa and Kume-jima were examined. According to paleontological studies on the molluscs, echinoids and foraminifers from the Yonabaru and Shinzato Formations by Noda, Kikuchi and Kawagara, repectively, the dominant and characteristic deep sea faunas were recognized. Most of deep sea molluscan faunas become dominant from the Yonabaru and were disappeared at the end of the Shinzato (MacNeiL, 1961, Noda, 1980, 1988, 1991, 1998) as like the echinoid faunas (Kikuchi's research). Thatcheria shows similar biogeographical distribution with that of Teramachia. Phanerolepida shows peculiar morphological variation and shows similar distitribution with that of Teramachia on both sides of the Pacific. Most of deep sea mollsucs had been appeared from the Yonabaru and disappeared at the end of the Shinzato. A total of 112 species of benthic foraminifers from the late Miocene to Pliocene Maja and Aka Formations were identified by Kawagata and show the bathymetric changes from 100 to 50 m in their depositional depth.
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