Postdoctor YANG Kuifeng and his teacher FAN Hongrui report the occurrence and characteristics of abundant carbonatite and mafic dykes from around the Bayan Obo giant rare earth element (REE) deposit in the northern margin of the North China Craton (NCC). The field relations show that the mafic dykes cut across the carbonatite dykes and the banded REE ore body.

Their geochemical characters including major and trace elements as well as REE patterns also attest to a common tectonic environment of magma generation and emplacement within a continental margin rift. The extensive mafic and carbonatitic magmatisms are associated with an extensional event that resulted in the formation of the Bayan Obo rift in the northern margin of the NCC, which we correlate with the final stages of fragmentation of the Columbia supercontinent amalgam.

Fig. 1 The configuration of the supercontinent Columbia during 1.35–1.20 Ga as proposed in this study. (Image by YANG)

Yang et al. Mesoproterozoic mafic and carbonatitic dykes from the northern margin of the North China Craton: Implications for the final breakup of Columbia supercontinent. Tectonophysics, 2011, 498: 1-10（Download Here）