日本海東縁ガスハイドレート調査(MD179)における間隙水の地球化学  [in Japanese] Geochemistry of pore waters from gas hydrate research in the eastern margin of the Japan Sea (MD179)  [in Japanese]

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Abstract

Pore waters collected from the eastern margin of the Japan Sea including gas hydrate fields off Joetsu were analyzed for concentrations of major and minor dissolved species in order to characterize fluid migration in high methane potential area. Rapid decreases of sulfate concentration and accompanying increases of alkalinity and hydrogen sulfide concentrations point to active diagenesis of organic matter such as anaerobic methane oxidation at the sulfate-methane interface, indicating high methane flux and subsequent gas hydrate formation near the seafloor on the Umitaka Spur and Joetsu Knoll. Gas hydrate occurrences are inferred generally by ion dilution and enrichment in <sup>18</sup>O and deuterium of pore waters, ion enrichment and depletion in <sup>18</sup>O and deuterium, to the contrary, indicate rapid growth of massive gas hydrate exceeding ion/water diffusion. Alkalinity increase also results in the precipitation of carbonates near the seafloor, corresponding to rapid decrease of Ca concentration. Pore water geochemistry changes remarkably in the shallow interval, induced mainly by active methane flux to the water column. Concentration of Cl and isotopic compositions of oxygen and hydrogen reflect inputs of deep fluids as well, deep-sourced material can be delivered to the shallow interval. Long-termed fluid migration is also evident in the research area.

Journal

  • Journal of the Japanese Association for Petroleum Technology

    Journal of the Japanese Association for Petroleum Technology 77(4), 262-267, 2012-07-01

    The Japanese Association for Petroleum Technology

References:  22

Cited by:  1

Codes

  • NII Article ID (NAID)
    10030879227
  • NII NACSIS-CAT ID (NCID)
    AN00130976
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    03709868
  • NDL Article ID
    024006572
  • NDL Call No.
    Z17-178
  • Data Source
    CJP  CJPref  NDL  IR  J-STAGE 
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