Primordial rare gases in Belgica-7904 (C2) carbonaceous chondrite
Belgica-7904 (C2) carbonaceous chondrite was analyzed for rare gas isotopic compositions with stepwise heating extraction method. Primordial rare gases are dominant, whereas the concentrations of radiogenic ^4(He) and ^<40>(Ar) are lower than those to be expected from radioactive decay. Cosmic...
| Main Authors: | , , |
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| Format: | Report |
| Language: | English |
| Published: |
Okayama University of Science/Okayama University of Science/Okayama University of Science
1984
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| Subjects: | |
| Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1729 http://id.nii.ac.jp/1291/00001729/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1729&item_no=1&attribute_id=18&file_no=1 |
| Summary: | Belgica-7904 (C2) carbonaceous chondrite was analyzed for rare gas isotopic compositions with stepwise heating extraction method. Primordial rare gases are dominant, whereas the concentrations of radiogenic ^4(He) and ^<40>(Ar) are lower than those to be expected from radioactive decay. Cosmic-ray exposure age of 0.7 my was obtained with cosmogenic ^<21>(Ne). Ne-E component was found in a 900-1100℃ range and its concentration was 1.2×(10)^<-9>(cm)^3 STP/g. Excessive heavy Xe isotopes in a 900℃ fraction have CCF-Xe spectrum. ^<20>(Ne), ^<84>(Kr) and ^<132>(Xe) in the highest temperature fraction of 1800℃ are enriched. The enrichments may be due to a stellar nucleosynthesis or due to a neutron irradiation of high temperature condensates. |
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