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Development of age determination method using U-Th isotope disequilibrium for the prediction of volcanic eruption

Research Project

Project/Area Number 11554021
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section展開研究
Research Field Petrology/Mineralogy/Science of ore deposit
Research InstitutionOKAYAMA UNIVERSITY

Principal Investigator

NAKAMURA Eizo  Institute for Study of the Earth's Interior, Okayama University Professor, 固体地球研究センター, 教授 (80201672)

Co-Investigator(Kenkyū-buntansha) MORIGUTI Takuya  Institute for Study of the Earth's Interior, Okayama University Assistant Professor, 固体地球研究センター, 助手 (70304342)
MAKISHIMA Akio  Institute for Study of the Earth's Interior, Okayama University Associate Professor, 固体地球研究センター, 助教授 (70219301)
Project Period (FY) 1999 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥11,700,000 (Direct Cost: ¥11,700,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2000: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1999: ¥6,600,000 (Direct Cost: ¥6,600,000)
KeywordsU-Th isotope disequilibrium / Th-Ra isotope disequilibrium / Magma process / Miyakejima / Isochron / TIMS / Analytical precision / Half-life / 火山噴火予知 / ウラン / トリウム / 固位体非平衡 / アイスランド / 表面電離型質量分析計 / スパイク / 噴火予知 / 放射非平衡 / 同位体 / 火山岩斑晶鉱物 / 火山層序 / ICP-MS / 三宅島火山 / マグマ分化プロセス / U-Th同位体測定
Research Abstract

In order to estimate the time scale of magma processes beneath island arc, we have developed new chimerical separation methods and highly precise isotope analyses for U, Th and Ra. These techniques were first applied to lavas from Miyakejima Island together with comprehensive petrological and geochemical investigations using major and trace element compositions and B-Sr-Nd-Pb isotopic compositions. The inferred genesis and transportation mechanism of magma with subduction component derived from descending slab in the wedge mantle beneath Miyakejima is summarized as follows:
^<238>U-^<230>Th disequilibrium observed in Miyakejima lavas with large 238U excess implies metasomatism of depleted mantle by fluid-related processes, as also suggested by the trace element and B-Sr-Nd-Pb isotope systematics. In the equiline diagram, trends observed in Stages 1 and 2 indicate two different isochrones with common initial ^<230>Th/^<232>Th ratios. The interval of individual fluid-release is obtained a … More s 15 kyr between Stages 1 and 2, and 3 kyr between Stages 2 and 3. ^<226>Ra-^<230>Th disequilibrium observed in some lavas suggests that the minimum interval of the fluid-release is approximately 1 kyr, indicating that the fluid-release and subsequent melt generation in the wedge mantle are episodic events intermittently occurring within 1-15 kyr. The ^<226>Ra-^<230>Th disequilibrium constraints the ascending rate of slab components as >45 m/yr, leading to the existence of crack in the wedge mantle. In contrast, Stages 3 and 4 samples depict a mixing trend in the equiline diagram between old andesitic magma and newly injected primitive magma. The involvement of primitive magma generally decreases from Stage 3 towards present, implying that primitive magma system is nearly closed system. Residence time of the differentiated magma in the crust is approximately 10 kyr, which is factor of two longer than theoretically obtained result. This may be due to the continuous heat supply from neighboring magma injection. Less

Report

(4 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • 1999 Annual Research Report
  • Research Products

    (32 results)

All Other

All Publications (32 results)

  • [Publications] Yokoyama, T., Makishima, A.Nakamura, E.: "Separation of thorium and uranium from silicate rock samples using two commercial extraction chromatographic resins"Analytical chemistry. 71. 135-141 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Makishima, A.Nakamura, E.: "Evaluation of the coprecipitation of incompatible elements with fluoride during silicate rock dissolution by acid digestion"Chemical Geology. 157. 175-187 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Makishima, A., Nakamura, E.: "Precise analysis of 234U/238U ratio using UO^<2+> ion with thermal ionization mass spectrometry for natural samples"Chemical Geology. 181. 1-12 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Kobayashi, K., Nakamura, E.: "Geochemical evolution of Akagi Volcano, Northeast Japan"Journal of Petrology. 42. 2303-2331 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Makishima, A., Nakamura, E.: "Determination of total sulfur at mgg-1 levels in geological materials by oxidation of sulfur into sulfate …"Analytical chemistry. 73. 2547-2553 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Nakamura, E.: "Precise determination of ferrous iron in silicate rocks"Geochimica et Cosumochimica Acta. 66. 1085-1093 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Makishima, A. and Nakamura, E.: "Separation of thorium and uranium from silicate rock samples using two commercial extraction chromatographic resins,"Anal. Chem. 71. 135-141 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Makishima, A. and Nakamura, E.: "Evaluation of the coprecipitation of incompatible trace elements with fluoride during silicate rock dissolution by acid digestion."Chem. Geol.. 157. 175-187 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T., Makishima, A. and Nakamura, E.: "Precise analysis of 234U/238U ratio using UO2+ ion with thermal ionization mass spectrometry for natural samples."Chem. Geol.. 181. 1-12 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Kobayashi, K. and Nakamura, E., Geochemical Evolution of Akagi Volcano: "Northeast Japan: Implications for Interaction between Island Arc Magma and Lower Crust, and Generation of Isotopically"J. Petrol.. 42. 2303-2331 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Makishima, A. and Nakamura, E.: "Determination of total sulfur at mg g-1 levels in geological materials by oxidation of sulfur into sulfate with in situ generation of bromine using isotope dilution high resolution"Anal. Chem.. 73. 2547-2553 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Yokoyama, T. and Nakamura, E.: "Precise determination of ferrous iron in silicate rocks."Geochim. Cosmochim. Acta. 66. 1085-1093 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Takei, H.: "Formation and supression of Alf3 during HF digestion of rock samples in Tetlon bomb for precise trace element"Proc.Japan Acad Ser B.. 77. 13-17 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Yokoyama, T.: "Precise analysis of ^<234>u/^<238>u ratio using uo^<2+> with therinal ionization inass spectramet by for natural"chem.Geol.. 181. 1-12 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Nakano, T.: "Boron isotepe get chemistry of metasedimentary rocks and tourmalines in the sabduction subduction-zone"Phys.Earth Planet.Inter ors. 127. 233-252 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Kobayashi, K.: "Geochemical Evolution of Akagi Volcano, NE Japan: Implications for Interaction Between Island-arc Magma and Lower Crust, and Generation of Isotopically Various Magmas"J.Petrology. 42. 2303-2331 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Makishima.A: "Determination fo total sulter at μg g-1 lerels"Anal.Chem.. 73. 2547-2553 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Makishima.A: "A new group separation method of ruthenium"Anal.Chem.. 73. 5240-5246 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Yoshikawa,M.and E.Nakamara: "Geochemical evolution of the Horoman peridotite complex : Implications for melt extraction, metasomatism, and …… "Journal of Geopysical Research. 105. 2879-2901 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Hanyu,Y.and E.Nabamura: "Constraints on HIMN and EM by Sr and Nd isotopes re-examined."Earth Planets Spaces. 52. 61-70 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Yamamoto,H.and E.NaLaniura: "Timing of magmatic and metamorphic events in the Jijal Complex of the Kohistan arc deduced from Sm-Nd dating ……"The Geological Society of London. 170. 313-319 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Suzuki,T.,Akaogi,M.and E.Nakamura: "partitioning of major elements between garnet-structured minerals and silicats melts at pressure of 3-15Gpa"Physics of the Earth and Planetary Interiors. 120. 79-92 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Makishima,A,and E.Nakamara: "Determination of titanium at ugg^<-1> levels in milligram amounts of silicate materials by isotope dilution high res ……"The Royal Society of Chemistry. 15. 263-267 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Takei,H.,T.Yokayama,A.Makishima and E.Nakamura: "Formation and suppression of AlF3 during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS……"Proceedings of Japan Academy. 77. 13-17 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Nakano,T.and E.Nakamura: "Boron isotope geochemistry of metasedimentary rocks and tourmalines in a subduction-zone metamorphic suite"Physics of the Earth and Planetary Interiors. (in press). (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] Yokoyama,T.,A.Makishima and E.Nakamura: "Precise analysis of 234U/238U ratio using UO^+_2 ion with thermal ionization mass spectrometry for natural samples"Chemical Geology. (in press). (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] Yokoyama, Y., Makishima, A., and Nakamura, E.: "Separation of thorium and uranium from silicate rock samples using two commercial extraction chroma togtophic resins"Analytical Chemistry. 71. 135-141 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Yokoyama, Y., Makishima, A., and Nakamura, E.: "Evaluation of the coprecipitation of incompatible trace elements with fluoride during silicate rock dissolution by acid digestion"Chemical Geology. 157. 175-187 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Makishima, A., Nakamura, E., and Nakano, T.: "Determination of zirconium, niobium, hafnium and tantalum at nglg levels in geological materials by direct nebulization of samples HF Solution info FI-ICP-M"Geostandard Newsletters. 23. 7-20 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Makishima, A., and Nakamura, E.: "Determination of molybdenum, antimony and tungsten at sub micro-glg levels in geological materials by IO-FI-ICP-MS"Geostandard Newsletters. (印刷中). (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Hanyu, T. and Nakamura, E.: "Constraints on HIMU and EM by Sr and Nd isotopes re-examined"Earth, Planets and Space. (印刷中). (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Yoshikawa, M. and Nakamura, E.: "Geochemical evolution of the Horoman peridotite complex : Implications for melt extraction, matosomatism and compositional layering in the mantle"Journal of Geophysical Research. (印刷中). (1999)

    • Related Report
      1999 Annual Research Report

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Published: 1999-04-01   Modified: 2016-04-21  

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