Abstract
Ion microprone analyses of rare earth elements (REEs) have been performed for fine-grained refractory inclusions in Efremovka meteorite (CV3-reduced type), because they are most likely of condensation origin from the hot solar nebula. The results show various REE patterns, suggesting fractionation of REEs, i.e. separation of gas and refractory dust, under variable conditions. Condensation calculation has been performed for REEs using simple assumptions and the results were compared with the observed REE patterns trying to understand formation conditions of refractory inclusions, especially those of fine-grained ones.