Mineralogy, Petrography, and Oxygen Isotopic Compositions of Ultrarefractory Inclusions from Carbonaceous Chondrites

Fine-grained CAIs with Group II rare earth element (REE) patterns condensed from a gaseous reservoir from which the ultrarefractory (UR) REEs had been removed. The carriers of UR REEs are poorly known. Here we report on the mineralogy, petrography and O-isotope compositions of 25 CAIs, presumably UR (REEs have not yet measured), from CR2, CM2, C3.0, CO3.0‒3.6, CV3.1‒3.6, and CH3.0 carbonaceous chondrites (CCs).