Noble gases and K-Ar ages of five Rumuruti chondrites Yamato(Y)-75302, Y-791827, Y-793575, Y-82002, and Asuka-881988

• Main Authors: Nagao,Keisuke, Okazaki,Ryuji, Sawada,Shinobu, Nakamura,Noboru
• Format: Report
• Language: English
• Published: Laboratory for Earthquake Chemistry, Graduate School of Science, University of Tokyo/Laboratory for Earthquake Chemistry, Graduate School of Science, University of Tokyo/Graduate School of Science and Technology, Kobe University/Graduate School of Science and Technology, Kobe University 1999
• Subjects: Antarctic; The ''Y''; Yamato; Antarc*
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5946; http://id.nii.ac.jp/1291/00005946/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5946&item_no=1&attribute_id=18&file_no=1

Noble gases and K concentrations have been determined for aliquot samples prepared from the five Antarctic R-chondrites Yamato (Y)-75302,Y-791827,Y-793575,Y-82002,and Asuka (A)-881988. K-Ar ages of about 4.2Ga were obtained for Y-75302,Y-791827,Y-793575 and A-881988,while Y-82002 showed a slightly younger age of 3.9Ga. The Y-75302,Y-791827 and Y-82002 are enriched in solar light noble gases. Four meteorites Y-75302,Y-791827,Y-82002 and A-881988 have cosmic-ray exposure ages of about 20Ma, while the age of Y-793575 is about 7Ma. Based on the noble gas compositions and K-Ar ages, Y-75302 and Y-791827 are probably paired and Y-82002 may belong to this pair. Relatively high and variable ^<129>Xe/^<132>Xe ratios between 2-3.7 as well as enrichments of heavier Xe isotopes were observed in all R-chondrites.