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Relationships between the morphologic rates of diatom evolution and north Pacific Miocene circulation

Research Project

Project/Area Number 03640660
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Stratigraphy/Paleontology
Research InstitutionNational Science Museum

Principal Investigator

TANIMURA Yoshihiro  National Science Museum, Geology, Curator, 地学研究部, 室長 (80141985)

Co-Investigator(Kenkyū-buntansha) KOIZUMI Itaru  Hokkaido University,Geology and Mineralogy, Professor, 理学部, 教授 (20029721)
Project Period (FY) 1991 – 1992
Project Status Completed (Fiscal Year 1992)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1991: ¥1,800,000 (Direct Cost: ¥1,800,000)
KeywordsMiocene / diatom / morphologic rates of evolution / 海洋循環
Research Abstract

Several centric diatoms having plicate valve face have been reported from Pacific Neogene to Quaternary ranging in age from approximately 0 to 17 Ma ; Thalassiosira yabei group (=Thalassiosira brunii, T.flexosa, T.grunowii, T. mioplicata, T.moholensis, T.praeyabei, T.temperei, T.yabei, and others). These forms share a quite alike plication, one side convex and other side concave, of valve and intermediate forms occur fairly commonly among forms. Hence it appears that these plicated forms seem to be on the same evolutionary line.
To provide information for the relationship between the morphologic rates of evolution of T.yabei group and mid Miocene high diatom production associates with Miocene North Pacific paleoclimatic and paleoceanographic changes, measurements of valve dimensions were made on 11 morphotypes, classified in this study, from Middle to Late Miocene part of their evolutionary line.
The biometric evidence suggests that 1) the stock of this evolutionary line is T. praeyabei, 2) morphologic rates of evolution increases in Middle Miocene (15-13Ma), and 3) several descendants evolve from T.praeyabei at and around the interval. This increases in morphologic rates of evolution might have close relationship to auxospone formation which may be partly caused by intensified upwelling and high diatom production associated with mid Miocene cold events.
This lineage also will define new biozones in a diatom zonal scheme for the Pacific Neogene, and a new genus, Plicatodiscus will be proposed in a following work.

Report

(3 results)
  • 1992 Annual Research Report   Final Research Report Summary
  • 1991 Annual Research Report
  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] Yoshihiro TANIMURA: "Seasonal changes in flux and species composition of diatoms:Sediment trap results from the northwest Pacific,August 1986-November 1988." Bull.Natn.Sci.Mus.,Tokyo,Ser.C. 18. 121-154 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yoshihiro TANIMURA: "Distribution of diatom species in the surface sediments of Lutzow-Holm Bay,Antarctica." Centenary of Japanese Micropaleontology. 399-411 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yoshihiro Tanimura: "Seasonal changes in flux and species composition of diatoms : Sediment trap results from the northwest Pacific, August 1986 - November 1988" Bull.Natn.Sci.Mus., Tokyo, Ser.C. 18(4). 121-154 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yoshihiro Tanimura: "Distribution of diatom species in the surface sediments of Lutzow- Holm Bay, Antarctica" Centenary of Japanese Micropaleontology. 399-411 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary

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Published: 1991-04-01   Modified: 2016-04-21  

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