Postdoctor YANG Kuifeng and his teacher FAN Hongrui study detailed data from the different types of carbonatite dykes occurring in a larger area around the Bayan Obo rare-earth element ( REE) deposit, as well as from the massive ore-hosting dolomite marble, to understand the mineralogical and geochemical composition of the carbonatitic magmas and their evolutionary process.

This evolutionary trend suggests the crystal fractionation of the carbonatite magma. The massive ore-hosting dolomite marbles show comparable element content and Nd isotope composition, and a Sm–Nd isochron age similar to that of the carbonatite dykes, implying a close relationship during their magmatic origin. This interpretation is also supported by the intrusive contact between the ore-hosting dolomite marble and Mesoproterozoic Bayan Obo group, as well as the presence of wall-rock xenoliths in the dolomite marble.

Yang et al. Mesoproterozoic carbonatitic magmatism in the Bayan Obo deposit, Inner Mongolia, North China: Constraints for the mechanism of super accumulation of rare earth elements. Ore Geology Reviews. 2011, 40: 122-131 （Download Here）

Fig. 1. Plot of SrO (wt.%) versus FeO (wt.%) of the carbonatite dykes, ore-hosting dolomite marble and sedimentary carbonate rocks from Bayan Obo district.(Image by YANG Kuifeng)

Fig.2. Chondrite-normalized REE abundance diagram.(Image by YANG Kuifeng)