K-Ar Ages of Yamato-74 Meteorites

• Main Authors: Akeji Kamaguchi, Jun Okano
• Format: Report
• Language: English
• Published: Department of Chemistry, Faculty of Science, Osaka University/ 1979
• Subjects: Yamato; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=967; http://id.nii.ac.jp/1291/00000967/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=967&item_no=1&attribute_id=18&file_no=1

Measurements have been carried out on the isotopic compositions and contents of helium, neon and argon for three kinds of Yamato meteorites, which were petrologically classified into (a) L-chondrite (Yamato-74190-01), (b) H-chondrite (Yamato-74640-02) and (c) eucrite (Yamato-74159-01). K-Ar age for each sample was calculated to be (a) ~2.1 b.y., (b) ~4.5 b.y. and (c) ~4.3 b.y. From the isotopic correlation diagram for neon, it has been suggested that the neon of each sample consisted of a mixture of spallogenic neon and trapped one. ^3(He) exposure ages for the samples (a), (b) and (c) were calculated to be 25,12 and 27 m.y. and ^<21>(Ne) exposure ages to be 25,11 and 32 m.y., respectively.