Noble gas record and cosmic‐ray exposure history of the new CO3 chondrite Moss––Comparison with Lancé and other CO chondrite falls |
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| Authors: | Rainer BARTOSCHEWITZ Ulrich OTT Luitgard FRANKE Siegfried HERRMANN Yukio YAMAMOTO Keisuke NAGAO Morten BILET Thomas GRAU |
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| Affiliation: | 1. Bartoschewitz Meteorite Laboratory, Lehmweg 53, D‐38518 Gifhorn, Germany;2. Abteilung Geochemie, Max‐Planck‐Institut für Chemie, Joh.‐J.‐Becher‐Weg 27, D‐55128 Mainz, Germany;3. Laboratory for Earthquake Chemistry, Graduate School of Science, University of Tokyo, Hongo, Bunkyo‐ku, Tokyo 113‐0033, Japan;4. Astronomical Society of Norway, Maltrostveien 33a, 1430??s, Norway;5. European Research Center for Fireballs and Meteorites, Puschkinstra?e 23, D‐16321 Bernau, Germany |
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| Abstract: | Abstract– The Moss meteorite is the first CO chondrite fall after a time period of 70 yr and the least terrestrially contaminated member of its group. Its cosmic‐ray exposure (CRE) age (T3 ～ 13.5 Ma; T21 ～ 14.6 Ma) is distinct among CO chondrites and, within witnessed falls is the shortest after Lancé, which we have reanalyzed. Gas retention ages are approximately 3.95 × 109 yr (U/Th‐He) and approximately 4.43 × 109 yr (K/Ar), respectively. Trapped Ar, Kr, and Xe are present in Moss in abundances typical for CO chondrites, with “planetary” elemental and isotopic compositions. Presence of HL‐xenon from presolar diamonds is observed in the stepwise release analysis of Lancé. It may also be present in Moss, but it is difficult to ascertain in single‐step bulk analyses. It follows from our new data combined with a survey of the literature that the abundance of trapped gases in CO chondrites is not a good indicator of their petrological subtype. |
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