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Rumuruti chondrites: Noble gases, exposure ages, pairing, and parent body history
Author(s) -
SCHULTZ Ludolf,
WEBER Hartwig W.,
FRANKE Luitgard
Publication year - 2005
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2005.tb00963.x
Subject(s) - chondrite , regolith , meteorite , parent body , astrobiology , breccia , noble gas , geochemistry , geology , chemistry , physics , organic chemistry
— In this paper, we present concentration and isotopic composition of the light noble gases He, Ne, and Ar as well as of 84 Kr, 132 Xe, and 129 Xe in bulk samples of 33 Rumuruti (R) chondrites. Together with previously published data of six R chondrites, exposure ages are calculated and compared with those of ordinary chondrites. A number of pairings, especially between those from Northwest Africa (NWA), are suggested, so that only 23 individual falls are represented by the 39 R chondrites discussed here. Eleven of these meteorites, or almost 50%, contain solar gases and are thus regolithic breccias. This percentage is higher than that of ordinary chondrites, howardites, or aubrites. This may imply that the parent body of R chondrites has a relatively thick regolith. Concentrations of heavy noble gases, especially of Kr, are affected by the terrestrial atmospheric component, which resides in weathering products. Compared to ordinary chondrites, 129 Xe/ 132 Xe ratios of R chondrites are high.