冷凍マイクロトーム法による現生シャコガイ殻の酸素同位体比分析より推定される詳細な水温変化  [in Japanese] High resolution reconstruction of water temperature estimated from oxygen isotopic ratios of a modern <i>Tridacna</i> shell based on freezing microtome sampling technique  [in Japanese]

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Author(s)

    • 渡邊 剛 WATANABE Tsuyoshi
    • 北海道大学大学院地球環境科学研究科 Graduate School of Environmental Earth Science, Hokkaido University
    • 大場 忠道 OBA Tadamichi
    • 北海道大学大学院地球環境科学研究科 Graduate School of Environmental Earth Science, Hokkaido University

Abstract

A modern <i>Tridacna</i> (<i>Hippopus hippopus</i>) was collected on September 5,1993 from a coral reef at Ishigaki Island in Ryukyu Archipelago, Japan, in order to investigate the environmental changes recorded in the shell. We adopted freezing microtome technique for high resolution analysis of the oxygen isotope of the shell. A portion of the inner layer, where daily growth lines are observed under a microscope, was cut out vertically from the inner surface. A stick measuring 20x1x2mm was then placed in water and frozen. Using a microtome, 50um interval samples were pealed off the stick in a room maintained at -20℃. We determined the date of the formation of each sample by measuring the distance from the inner surface of the shell and by counting the daily growth lines. The water temperatures estimated from the oxygen isotopic values at 1-2 day intervals agreed very well (correlation coefficient: 0.90) with the observed water temperatures which have a seasonal temperature range between about 20℃ and 32℃. This implies that the <i>Tridacna</i> precipitates its shell in isotopic equilibrium with the surrounding sea water and that the oxygen isotope values are mainly determined by the water temperature.

Journal

  • Chikyukagaku

    Chikyukagaku 32(2), 87-95, 1998

    The Geochemical Society of Japan

References:  20

Cited by:  3

Codes

  • NII Article ID (NAID)
    110008679948
  • NII NACSIS-CAT ID (NCID)
    AN00141280
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0386-4073
  • NDL Article ID
    4480541
  • NDL Source Classification
    ZM41(科学技術--地球科学)
  • NDL Call No.
    Z15-645
  • Data Source
    CJP  CJPref  NDL  NII-ELS  J-STAGE 
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