Chikyukagaku
Online ISSN : 2188-5923
Print ISSN : 0386-4073
ISSN-L : 0386-4073
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Volume 31, Issue 4
Displaying 1-5 of 5 articles from this issue
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Review in series “New Approaches to Geochemistry”
The Shibata Award
  • Study on carbonate materials in earth's environment
    Yasushi KITANO
    1997 Volume 31 Issue 4 Pages 211-226
    Published: December 10, 1997
    Released on J-STAGE: December 22, 2016
    DOIhttps://doi.org/10.14934/chikyukagaku.31.211
    JOURNAL FREE ACCESS
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    The major component of carbonate materials distributing in the earth's environment is calcium carbonate. Calcium carbonate has interesting characteristics, that is, it has three different crystal forms such as calcite, vaterite and aragonite. Thus, the distribution of minor chemical species between parent solution and calcium carbonate precipitate is delicate but interesting. Since the influences of various cations, anions and organic materials dissolved in a parent solution on the polymorphic crystallization and the distribution of minor elements were clarified by the present author, the synthesis of (Ca, Mg) CO3 at low temperatures and pressures was first succeeded. It is also important that the amount of carbonate materials existing in the earth is very large and the greatest reservoir of carbon dioxide is carbonate materials. The present author estimated the sedimentation rate of marine carbonate through the geochemical balance of calcium ions after the careful examination on water-rock interaction on continent. He has tried to discuss the birth and evolution of air and sea through the discussion on those of carbon dioxide. Also the role of carbonate sedimentation in the sea on global warming has been clarified.
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Original Paper
  • Radioisotopic study on the ground waters of Okinawa Island, Japan
    Nobutaka TOMOYOSE, Akira TANAHARA, Morihisa TAKEMURA, Akira TOGUCHI, H ...
    1997 Volume 31 Issue 4 Pages 227-233
    Published: December 10, 1997
    Released on J-STAGE: December 22, 2016
    DOIhttps://doi.org/10.14934/chikyukagaku.31.227
    JOURNAL FREE ACCESS
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    The activities of natural radionuclides, 238U, 234U, 226Ra, 228Ra, 222Rn, 210Pb and 210Po in ground waters collected from Okinawa Island were measured. The 234U/238U activity ratios in most samples showed more or less unity, whereas, relatively high values of 2.0-4.0 were obtained in samples from Motobu area. 222Rn activities in the ground waters were much higher than the other uranium series nuclides. The 222Rn/226Ra activity ratios ranged from 3000 to 29000, and those for 210Po/210Pb were from 0.08 to 0.82. On the whole, activities of the nuclides in the ground waters at the studied points showed higher in the order of 222Rn≫210Pb>234U>238U>226Ra>210Po. In addition to α_recoil dissolution, the selective absorption and/or desorption by some organic or inorganic substances in the aquifer may be happening.
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  • Origin of sulfur and nitrogen oxides in acid precipitation at Nagoya and Matsue
    Koichiro NAGAMINE, Keiji SEKI, Kenichiro MAEDA, Katsuhiro YOSHIOKA, Yu ...
    1997 Volume 31 Issue 4 Pages 235-243
    Published: December 10, 1997
    Released on J-STAGE: December 22, 2016
    DOIhttps://doi.org/10.14934/chikyukagaku.31.235
    JOURNAL FREE ACCESS
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    Sulfur and nitrogen oxides in acid precipitation were observed at Nagoya and Matsue by collecting rainwater in each rainfall. The observation results using trajectory analysis show that these oxides mainly came from urban area at Nagoya, and their mass did not change much with season and the route of trajectories. In contrast, sulfur oxide mainly came from biological origin rather than urban one at Matsue inferred from nssδ34S data, and its mass increased in winter. The seasonal and trajectorical variation in nssSO42-/NO3- ratio and nssδ34S implies that the contribution of continental and/or maritime biogenic sulfur to sulfur oxide in acid precipitation increased in winter at Matsue due to the seasonal wind.
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Abstract of doctoral thesis
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