Oxygen Isotope Variation of CM and Related Chondrites: Multiple Parent Bodies or a Single Heterogeneous Source?

Franchi I. A., Greenwood R. C., Howard K. T., King A. J., Lee M. R., Anand M., Findlay R.

82nd Annual Meeting of The Meteoritical Society 2019

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“CMs are the largest group of carbonaceous chondrites (CC), comprising ~35% of observed CC falls [1]. The CMs display evidence for significant aqueous alteration, with considerable variation in the nature and amount of secondary minerals reported across the group. Indeed, many CMs are complex breccias containing a range of different lithologies, often showing significant mineralogical variation [e.g. 2, 3]. Here we present the results of an extensive oxygen isotope study of a wide range of CMs and related meteorites. Our aim is to explore the diversity and linkages within and between samples in order to understand the nature of the CM parent body(s). The results of this work will have important implications for the forthcoming detailed investigation of samples returned by Hayabusa2 and OSIRIS-REx from their respective C-type target asteroids. “