Noble gases in Yamato-793274 and -86032 lunar meteorites

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Author(s)

    • Takaoka Nobuo
    • Department of Earth Sciences,Faculty of Science, Yamagata University
    • Yoshida Yo-ichi
    • Department of Earth Sciences,Faculty of Science, Yamagata University

Abstract

Isotopic abundances of noble gases are reported for whole rock samples, mineral and grain size separates prepared from lunar meteorites Yamato-793274 and -86032. Y-793274 is rich in trapped solar gases, whereas Y-86032 is depleted in them, resembling the Y-82192 and -82193 lunar meteorites. From measurements of radiogenic Ar, the K-Ar age of Y-86032 is calculated to be 3940±240 Ma, in agreement with the K-Ar and Ar-Ar ages for Y-82192 and -82193. From measurements of cosmogenic noble gases, the total duration of cosmic-ray exposure is calculated to be 510±140 and 11±1 Ma for Y-793274 and -86032,respectively. The exposure age of Y-86032 is in good agreement with that for Y-82192/3. The agreement in the K-Ar and exposure ages as well as in the trapped gas abundances supports the earlier result that Y-86032 is paired with Y-82192 and -82193. Y-793274 experienced most of exposures to cosmic-rays in the lunar regolith because the transit time from the moon to the earth has been reported to be very short, whereas it is supposed that Y-86032 experienced a large part of cosmic-ray exposure in the interplanetary space during the flight from the moon to the earth.

Journal

  • Proceedings of the NIPR Symposium on Antarctic Meteorites

    Proceedings of the NIPR Symposium on Antarctic Meteorites 5, 36-48, 1992-03

    National Institute of Polar Research

Codes

  • NII Article ID (NAID)
    110000029946
  • NII NACSIS-CAT ID (NCID)
    AA10784627
  • Text Lang
    ENG
  • ISSN
    09145621
  • Data Source
    NII-ELS 
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