40Ar-39Ar analyses of Y-74063 and ALH-78230: Consortium study onunique meteorites from Antarctica

• Main Authors: Kaneoka, Ichiro, Takaoka, Nobuo, Yanai, Keizo
• Language: English
• Published: National Institute of Polar Research 1992
• Subjects: Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/record/4578/files/KJ00000036384.pdf; https://doi.org/10.15094/00004578; https://nipr.repo.nii.ac.jp/records/4578

P(論文) As part of a consortium study on unique meteorites from Antarctica, ^<40>Ar-^<39>Ar analyses were performed for two meteorites Y-74063 and ALH-78230,which are related to lodranite and the Acapulco meteorite. Y-74063,93 shows an ^<40>Ar-^<39>Ar plateau age of 4556±53 Ma, containing about 10^<-6>cm^3STP/g trapped ^<36>Ar. ALH-78230,55 also indicates an ^<40>Ar-^<39>Ar plateau age of 4531±23 Ma in the higher temperature fractions, but the lower temperature fractions suggest the occurrence of a later degassing event around 400-500 Ma. Trapped ^<36>Ar is about 10^<-8>cm^3STP/g. These results indicate that the two meteorites Y-74063 and ALH-78230 experienced different thermal histories. departmental bulletin paper