Petrology and bulk chemistry of Yamato-82094, a new type of carbonaceous chondrite - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Meteoritics and Planetary Science Année : 2014

Petrology and bulk chemistry of Yamato-82094, a new type of carbonaceous chondrite

Résumé

Carbonaceous chondrites are classified into several groups. However, some are ungrouped. We studied one such ungrouped chondrite, Y-82094, previously classified as a CO. In this chondrite, chondrules occupy 78 vol%, and the matrix is distinctly poor in abundance (11 vol%), compared with CO and other C chondrites. The average chondrule size is 0.33 mm, different from that in C chondrites. Although these features are similar to those in ordinary chondrites, Y-82094 contains 3 vol% Ca-Al-rich inclusions and 5% amoeboid olivine aggregates (AOAs). Also, the bulk composition resembles that of CO chondrites, except for the volatile elements, which are highly depleted. The oxygen isotopic composition of Y-82094 is within the range of CO and CV chondrites. Therefore, Y-82094 is an ungrouped C chondrite, not similar to any other C chondrite previously reported. Thin FeO-rich rims on AOA olivine and the mode of occurrence of Ni-rich metal in the chondrules indicate that Y-82094 is petrologic type 3.2. The extremely low abundance of type II chondrules and high abundance of Fe-Ni metal in the chondrules suggest reducing condition during chondrule formation. The depletion of volatile elements indicates that the components formed under high-temperature conditions, and accreted to the parent body of Y-82094. Our study suggests a wider range of formation conditions than currently recorded by the major C chondrite groups. Additionally, Y-82094 may represent a new, previously unsampled, asteroidal body.
Fichier principal
Vignette du fichier
MAPS_Kimura_14.pdf (442.57 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

insu-00981582 , version 1 (22-04-2014)

Identifiants

Citer

M. Kimura, Jean-Alix J-A Barrat, M.K. Weisberg, N. Imae, A. Yamaguchi, et al.. Petrology and bulk chemistry of Yamato-82094, a new type of carbonaceous chondrite. Meteoritics and Planetary Science, 2014, 49 (3), pp.346-357. ⟨10.1111/maps.12254⟩. ⟨insu-00981582⟩
129 Consultations
382 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More