Presolar grain inventories of the ungrouped C3 Adelaide and the CV3 RBT 04133

Presolar grains are particularly abundant in primitive extraterrestrial materials such as IDPs [e.g. 1-3] and the matrices of the least altered chondrites [4-6]. To date, the presolar silicate and oxide inventories of the primitive chondrites Acfer 094 [4-7] and ALHA 77307 [7] have been reported extensively. More recently, the search for presolar silicates and oxides has been extended to the CR [8,9] and ungrouped chondrites [10]. Here we report the presolar grain inventories (silicates, oxides, SiC, and other C-anomalous phases) determined for Adelaide and RBT 04133 by Nano-SIMS raster ion imaging. Adelaide (an ungrouped C3)was chosen for this study because (i) it is primitive and (ii) it was previously reported to have a low presolar silicate abundance of ~41 ppm [11] in comparison to Acfer 094 and ALHA 77307; 90-175 [7,12] and 95 ppm respectively [7]. RBT 04133 (a mildly thermally altered CV3) was also analysed as part of an ongoing study [13]