AOAs isotopic composition

Another argument that the 0-rich end-member was a ubiquitous component of primitive solids is that it is found in many different chemical forms (different minerals) in many classes of meteorites CAls and amoeboid olivine aggregates (AOAs) from Efremovka (CV3) (Aleon et al., 2002 Fagan et al., 2002), AOA from a CO chondrite, Y 81020 (Itoh et al, 2002), and CAl and AOA from CM and CR chondrites (Krot et al., 2002). This isotopic composition can also serve as an end-member for the chondrule mixing line in Figure 2. 

A The relationship between chondrules, CAIs, and AOAs The contrasting mineralogy of CAIs and chondrules indicates that they formed at different nebular temperatures and perhaps in different nebular environments. This is confirmed by oxygen isotope studies which show that there are significant oxygen isotope compositional differences between chondrules and refractory CIAs and AOAs. Chondrules from C and O chondrites also have different oxygen isotope compositions and appear to have formed in different nebular environments. In contrast, CAIs from all chondrite types and AOAs are isotopically similar and share the... 

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