40Ar-39Ar analyses of an Antarctic meteorite Yamato-791197 of probable lunar origin
^<40>Ar-^<39>Ar analyses have been applied to an Antarctic meteorite Yamato-791197 (Y-791197), an anorthositic regolith breccia of probable lunar origin (YANAI and KOJIMA, Mem. Natl Inst. Polar Res., Spec. Issue, 35,18,1984). The clast sample (Y-791197,96) shows a plateau ^<40>Ar-^...
| Main Authors: | , |
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| Format: | Report |
| Language: | English |
| Published: |
Geophysical Institute, Faculty of Science, University of Tokyo/Department of Earth Sciences, Faculty of Science, Yamagata University
1986
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| Subjects: | |
| Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1957 http://id.nii.ac.jp/1291/00001957/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1957&item_no=1&attribute_id=18&file_no=1 |
| Summary: | ^<40>Ar-^<39>Ar analyses have been applied to an Antarctic meteorite Yamato-791197 (Y-791197), an anorthositic regolith breccia of probable lunar origin (YANAI and KOJIMA, Mem. Natl Inst. Polar Res., Spec. Issue, 35,18,1984). The clast sample (Y-791197,96) shows a plateau ^<40>Ar-^<39>Ar age of 4065±93 Ma at higher temperatures, which corresponds to typical age groups obtained for lunar rocks of highland origin. The matrix sample (Y-791197,97) contains a large amount of trapped Ar (^<40>Ar : ∿9×(10)^<-4>(cm)^3STP/g) with the ^<40>Ar/^<36>Ar ratio of about 2.5 at higher temperatures, which implies that the trapped Ar is mostly of solar wind origin. This makes it difficult to estimate a reasonable ^<40>Ar-^<39>Ar age for this portion. The present result supports a presumption that Y-791197 originated from the moon's surface as a lunar highland breccia. |
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