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Boron and lithium isotopic fractionations during seawater basalt interaction.

Research Project

Project/Area Number 06640636
Research Category

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

Allocation TypeSingle-year Grants
Research Field 地球化学
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

CHIDA Hitoshi  Kyushu Univ.Dept.of Earth and Planet.Sci.Associate Prof., 理学部, 助教授 (30144736)

Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywordsseawater / basalt / hydrothermal fluid / mid-ocean ridge / boron / lithium / fractionation / 水 / 岩石相互作用 / 同位体 / 熱水変質
Research Abstract

Seawaer and basalt are reacted using the Dickson-type and the cold-seal type equipments as 150 and 300゚C.The final target of this study is to measure boron and lithium isotopic fractionation during seawater-basalt interaction. Isotopic ratios of these two elements are the potential indicator whether seawater has reacted with fresh basalt or with altered basalt. The change in seawater chemistry during the reaction was continuously monitored using the Dickson-type equipment. The cold-seal type equipment was used to make samples, which are free from contamination, especially boron contamination from ambient air. Both equipments were constructed during this study from commercial pressure vessels and electric furnaces. The results obtained by the Dickson-type equipments are summarized as follows : After the temperature of the system was elevated, Mg and SO_4 concentrations in seawater decrease. On the other hand, K concentration increases and Ca also increases after initial depletion. The pH of the seawater decreases initially, but increases later. The change in seawater chemistry were caused by the reaction of Mg in seawater and basalt. Mg in seawater is used to produce hydrous alteration mineral, which makes the seawater pH low. Ca and K are released from the altered basalt instead of Mg. Ca and SO_4 ions form anhydrite (CaSO_4) and SO_4 ion concentration decreases. The rate of the Mg decreace is linear to the logarithm of the reaction time. From the quenched solid sample, smectite was detected by XRD.Boron isotopic compositions of samples will be measured in the coming academic year.

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] Chiba, H.: "Chemical Modeling of Seawater-Rock Interaction : Effect of Rock-type on the Fluid Chemistry and Mineral Assemblage." Biogeochemical Processes and Ocean Flux in the Western Pacific. 469-486 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 益田晴恵: "TAGマウンドにおける熱水変質鉱物の分布と化学組成" JAMSTEC 深海研究. 11. 111-124 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Gamo, T.: "In situ flow-through analysis of dissolved silica over the TAG hydrothermal mound, Mid-Atlantic ridge." JAMSTEC J.Deep Sea Research. 111. 103-110 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nakashima, K.: "Hydrothermal mineralization in the Mid-Okinawa Trough." Biogeochemical Processes and Ocean Flux in the Western Pacific. 487-508 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Humpris, S.E.: "The internal structure of an active seafloor massive sulphide deposit." Nature.377. 713-716 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Gamo, T.et al.: "Mariana 1992 diving Surveys by "Shinkai 6500"(Y9204 cruise) : Revisits to the Mid-Mariana hydrothermal area and discovery of hydrothermal vents in the suouthern Mariana region." JAMSTEC J.Deep Sea Res.10. 153-162 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Humpris, S.E.et al.: "The internal structure of an active seafloor massive sulphide deposit" Nature. 377. 713-716 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Chiba, H.: "Chemical Modeling of Seawater-Rock Interaction : Effect of Rock-type on the Fluid Chemistry and Mineral Assemblage." "Biogeochemical Processes and Ocean Flux in the Western Pacific". 469-486 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nakashima, K.et al.: "Hydrothermal mineralization in the Mid-Okinawa Trough." "Biogeochemical Processes and Ocean Flux in the Western Pacific". 487-508 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Masuda, H.et al.: "Ddistribution and chemical charactersitics of hydrothermal alteration minerals recovered from the TAG active mound, MAR 26゚N." JAMSTEC J.Deep Sea Res.11. 111-124 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Gamo, T.et al.: "In situ flow-through analysis of dissolved silica over the TAG hydrothermal mound, Mid-Atlantic ridge." JAMSTEC J.Deep Sea Res.11. 103-110 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Chiba,H.: "Chemical Modeling of Seawater-Rock Interaction: Effect of Rock-type on the Fluid Chemistry and Mineral Assemblage." Biogeochmical Processes and Ocean Flux in the Western Pacific. 469-486 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 益田晴恵: "TAGマウンドにおける熱水変質鉱物の分布と化学組成" JAMSTEC深海研究. 11. 111-124 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Gamo,T.: "In situ flow-through analysis of dissolved silica over the TAG hydrothermal mound, Mid-Atlantic ridge." JAMSTEC J. Deep Sea Research. 111. 103-110 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Nakashima,K.: "Hydrothermal mineralization in the Mid-Okinawa Trough." Biogeochmical Processes and Ocean Flux in the Western Pacific. 487-508 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Humpris,S.E.: "The internal structure of an actire seafloor massive sulphide deposit." Nature.377. 713-716 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Chiba,H.: "Chemical Modeling of Seawater-Rock Interaction:Effect of Rock-type on the Fluid Chemistry and Mineral Assmblage." Biogeochemical Processes and Ocean Flux in the Western Pacific. (印刷中). (1995)

    • Related Report
      1994 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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