Bayan Obo, a rare earth element (REE)-Fe-Nb ore deposit, located in central InnerMongolia, near the contact between the North China Platform and Inner MongoliaHercynian Geosyncline, is a unique deposit with a combination of multi-sources, multi-stagesand multi-geneses. The orebodies occur comformably with the host rocks in stratoid,lenticular, lense and brush shapes within the dolomite of the Middle Proterozoic Bayan Obo