Petrology of Amoeboid Olivine Aggregates in Antarctic CR Chondrites: Evidence for Aqueous Alteration and Shock Metamorphism

• Main Authors: Yamaguchi, A., Komatsu, M., Fagan, T. J., Yasutake, M., Mikouchi, T., Zolensky, M. E.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2017
• Subjects: Geosciences (General); Antarctic; Antarc*
• Online Access: http://hdl.handle.net/2060/20170009177

CR chondrites are the group of carbonaceous chondrites that preserve records of formation of their components in the solar nebula. Although they are affected by aqueous alteration, many chondrules and CAIs are well-preserved, suggesting they have experienced little thermal metamorphism. We have been investigating the petrologic variations among the CR chondrites in Japanese-NIPR Antarctic meteorite collection. Especially we focused on the petrology of amoeboid olivine aggregates (AOAs) in order to understand secondary alteration on CR chondrite parent body. AOAs are composed of fine-grained forsteritic olivine and refractory minerals formed by condensation from solar nebula, and can be used as sensitive indicators of secondary alteration processes.