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A study of relation between undifferentiated and differentiated meteorites based on noble gas elemental and isotopic compositions

Research Project

Project/Area Number 15540464
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Geochemistry/Astrochemistry
Research InstitutionThe University of Tokyo

Principal Investigator

MIURA Yayoi  The University of Tokyo, Earthquake Research Institute, Research Associate, 地震研究所, 助手 (90282730)

Co-Investigator(Kenkyū-buntansha) NAGAO Keisuke  The University of Tokyo, Laboratory for Earthquake Chemistry, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (40131619)
Project Period (FY) 2003 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥2,100,000 (Direct Cost: ¥2,100,000)
KeywordsNoble gases / Meteorite / Differentiated meteorite / Aubrite / Chondrite / Formation age / Cosmic-ray exposure age
Research Abstract

Differentiated bodies (differentiated meteorites and planets) are thought to have been formed from materials like primitive meteorites (=chondrites). However, details about relation between them and differentiation processes are still questions. In this research project, we tried to have better understanding them based on noble gas isotope studies. For this, noble gas elemental and isotopic compositions in several classes of differentiated meteorites (aubrites, angrite, brachinite and lunar meteorites) and chondrites have been determined with a mass spectrometer. Remarkable results we obtained are as follows.
(1)Origin of aubrites : Aubrites are only achondrites that have a chondrite-pair for oxygen isotopic compositions. Therefore, it is interesting to study relation of aubrites with the chondrites (enstatite chondrites) and to clear the process of aubrite evolution. We have measured nine aubrites for noble gases and five aubrites for oxygen isotopes, from which we concluded that (i)so … More me of the measured aubrites contain chondritic primordial noble gases, but it is likely originated from chondritic clasts and not a indigenous signature. (ii)^<244>Pu-derived fission Xe has been observed in some aubrites. The Pu/U ratios range in those observed in chondrites and other achondrites, which indicates that aubrites were formed within several hundreds m.y.after the solar system formation. (iii)The distribution of comic-ray exposure ages for aubrites is different from that for enstatite chondrites, implying that orbits of these parent asteroids are probably different.
(2)Primordial noble gases in chondrites : Although the majority of primordial noble gases in chondrites are often believed to be "Q" type noble gases, we found another component that is the major component in some (or most) unequilibrated ordinary chondrites. It shows some characteristic features ; enrichments in lighter elements (Ar/Xe and Kr/Xe ratios are higher than those of Q), low release temperatures (〜1100℃ compared with〜1300℃ for Q) and trap in a HCl soluble phase.
A mini-oven system for extracting noble gases from mg or sub-mg samples has been designed and constructed. It enables to melt a sample on a Pt-wire with small power (e.g., 〜30W with φ0.6mm Pt-wire). Less

Report

(3 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • Research Products

    (16 results)

All 2004 2003 Other

All Journal Article (12 results) Publications (4 results)

  • [Journal Article] Orphan radiogenic noble gases in lunar breccias : Evidence for planet pollutin of the Sun ?2004

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A.
    • Journal Title

      ICARUS 170

      Pages: 17-23

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Noble gases in the Dhofar 489 lunar meteorite2004

    • Author(s)
      Miura Y.N., Nagao K.
    • Journal Title

      Meteoritics and Planetary Science 39

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] Early earth evolution recorded in lunar soil ?2004

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A., Seki K., Hashizume K.
    • Journal Title

      Geochimica et Cosmochimica Acta 68

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Orphan radiogenic noble gases in lunar breccias : Evidence for planet pollution of the Sun ?2004

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A.
    • Journal Title

      Icarus 170

      Pages: 17-23

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Noble gases in the Dhofar 489 lunar meteorite.2004

    • Author(s)
      Miura Y.N., Nagao K.
    • Journal Title

      Meteoritics and Planetary Science 39

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Early earth evolution recorded in lunar soil?2004

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A., Seki K., Hashizume K.
    • Journal Title

      Geochimica et Cosmochimica Acta 68

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] Trapped noble gas component and thermal histories of unequilibrated ordinary chondrites2003

    • Author(s)
      Miura Y.N., Sugiura N., Kiyota K., Nagao K.
    • Journal Title

      Meteoritics and Planetary Science 38

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Further examination of "Planet-pollution"as a source for the parentless radiogenic noble gases in lunar soils2003

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A.
    • Journal Title

      Meteoritics and Planetary Science 38

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Noble gases in two hot desert eucrites, DHO007 and DHO2752003

    • Author(s)
      Miura Y.N., Nagao K.
    • Journal Title

      Geochimica et Cosmochimica Acta 67

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Trapped noble gas component and thermal histories of unequilibrated ordinary chondrites.2003

    • Author(s)
      Miura Y.N., Sugiura N., Kiyota K., Nagao K.
    • Journal Title

      Meteoritics and Planetary Science 38

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Further examination of "Planet-pollution" as a source for the parentless radiogenic noble gases in lunar soils.2003

    • Author(s)
      Ozima M., Miura Y.N., Podosek F.A.
    • Journal Title

      Meteoritics and Planetary Science 38

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Noble gases in two hot desert eucrites, DHO007 and DH0275.2003

    • Author(s)
      Miura Y.N., Nagao K.
    • Journal Title

      Geochimica et Cosmochimica Acta 67

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Publications] Miura Y.N., Sugiura N., Kiyota K., Nagao K.: "Trapped noble gas component and thermal histories of unequilibrated ordinary chondrites"Meteoritic, Planetary Science. 38. A78 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Ozima M., Miura Y.N., Podosek F.A.: "Further examination of "Planet-pollution" as a source for the parentless radiogenic noble gases in lunar soils"Meteoritics and Planetary Science. 38. A32 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Miura Y.N., Nagao K.: "Noble gases in two hot desert eucrites, DHO007 and DHO275"Geochimica et Cosmochimica Acta. 67・18(S1). A296 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Ozima M., Miura Y.N., Podosek F.A.: "Orphan radiogenic noble gases in lunar breccias : Evidence for planet pollution of the sun?"ICARUS. (accepted). (2004)

    • Related Report
      2003 Annual Research Report

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Published: 2003-04-01   Modified: 2016-04-21  

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