Noble gases in Yamato-793274 and -86032 lunar meteorites

• 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

Details

• CRID: 1573950401540564224
• NII Article ID: 110000029946
• NII Book ID: AA10784627
• ISSN: 09145621
• Text Lang: en
• Data Source:
  • CiNii Articles