An amoeboid olivine aggregate surrounded by an igneous ferroan olivine-rich rim from CO3.0 chondrite DOM 08006.

Abstract

We have recently described type I chondrules surrounded by ferroan igneous rims in Graves Nunataks 95229 (CR2), Yamato 81020 (CO3.0) and Acfer 094 (ungrouped type 3) carbonaceous chondrites [1,2]. The mineralogy, textures, minor element and O-isotope compositions of these layered chondrules indicate that (1) the igneous rims are similar to type II chondrules, and (2) some type I chondrules were recycled in type II chondrule-forming regions. Some of the ferroan igneous rims contain 16O-rich (Δ17O < ？20‰) relict olivine grains which could be genetically related to amoeboid olivine aggregates (AOAs) that formed in the hot innermost region of the protoplanetary disk at the birth of the Solar System [e.g., 3], and were subsequently transported to chondrule-forming regions. Here we report the mineralogy, petrography, major- and minor- element abundances, and O-isotope distribution of an AOA surrounded by a ferroan igneous rim from Dominion Range (DOM) 08006 CO3.0 chondrite.