Abstract
The Bayan Obo supergiant carbonatite-related rare-earth-element-niobium-iron (REE-Nb-Fe) endogenetic deposit (thereafter as the Bayan Obo deposit), located at 150 km north of Baotou City in the Inner Mongolia Autonomous Region, is the largest rare-earth element (REE) resource in the world. Tectonically, this deposit is situated on the northern margin of the North China Craton and adjacent to the Xing’an-Mongolian orogenic belt to the south. The main strata within the mining area include the Neoarchean Se’ ertengshan Group and the Mesoproterozoic Bayan Obo Group. Generally, the rare earth, niobium, and iron mineralization within the deposit are intrinsically related to the dolomite carbonatites and the extensive alteration of the country rocks caused by the carbonatite magma intrusion. The alteration of country rocks can be categorized into three types: contact metasomatism (anti-skarn and skarn alteration), fenitization, and hornfelsic alternation. As indicated by previous studies and summarized in this review, the multi-element mineralization at Bayan Obo is closely associated with the metasomatic replacement of siliceous country rocks by carbonatite magmatic-hydrothermal fluids. The metasomatic process is comparable to the conventional skarnification that formed due to the intrusion of intermediate-acid magmatic rocks into limestone strata. However, the migration pattern of SiO2, CaO, and MgO in this novel metasomatic process is opposite to the skarn alteration. Accordingly, this review delineates, for the first time, an anti-skarn metallogenic model for the Bayan Obo deposit, revealing the enigmatic relationship between the carbonatite magmatic-hydrothermal processes and the related iron and rare earth mineralization. Moreover, this study also contributes to a better understanding of the REE-Nd-Fe metallogenetic processes and the related fluorite mineralization at the Bayan Obo deposit.©2023 China Geology Editorial Office.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
