Petrography and origin of refractory inclusions from the Murray and Murchison C2 chondrites

By freeze-thaw disaggregation, we have recovered a total of 47 refractory inclusions. New discoveries include the following: a hibonite-pyroxene spherule from Murray; a CaAl4O7-bearing spherule from Murchison; and a Sc-fassaite-bearing ultrarefractory inclusion from Murchison. Freeze-thaw disaggregation, combined with density separation and hand-picking as described is a proven method for recovering rare objects from carbonaceous chondrites. This method is especially effective on C2's due to their porosity and typically results in the discovery of new types of refractory inclusions. Because few refractory inclusions from Murray have been described, we studied this meteorite, although only a small amount of material (730 mg) was available for disaggregation. Many refractory inclusions from Murchison have been described, and we disaggregated a larger amount (approximately 18 g) of Murchison in an attempt to find new types of refractory inclusions, especially corundum-bearing ones.