ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Economic Geology
Volume 13 - 2025 | doi: 10.3389/feart.2025.1518194
This article is part of the Research TopicExploration, Development, and Protection of Earth’s Resources and Environment: Methods, Techniques, Applications, Prospects, Insights, and ProblemsView all 49 articles
Genesis of the Bayan Obo Fe-REE Deposit: Evidence from Mg Isotope and Geochemistry of Siderite Carbonatites, Inner Mongolia, China
Provisionally accepted
- 1Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, China
- 2PetroChina Xinjiang Oilfield Company, Karamay, China
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The Bayan Obo Fe-REE deposit, a world-renowned giant polymetallic ore concentration area, is located on the northern edge of the North China Craton, which borders on the Central Asian orogenic belt. Many studies have been conducted since the primary orebody was discovered, but its genesis has always been a fiercely debated issue. In recent years, the rapid development of Mg isotope research has shown promise in tracing mantle-derived igneous rocks and carbonatites, providing a new approach to studying the formation of the Bayan Obo deposit. In this study, we conducted Mg isotope composition and whole-rock geochemical analysis on the siderite carbonatites closely associated with the formation of the Bayan Obo deposit to reveal its genesis. Results show that the siderite carbonatites have high levels of Sr (796.3-6343.1 ppm), Ba (84.8-11593.0 ppm), and Mn (8319.8-48680.8 ppm), as well as rare earth element abundance (2696.8-20763.6 ppm), distinguishing them from sedimentary carbonate rocks. The δ26Mg variation range for the siderite carbonatites is −1.31 to −0.09‰, with a mean value of −0.37‰, similar to characteristics of dolomite carbonatites in the mining area. Integrating the results of this study with previous research, we propose that the Bayan Obo deposit formed through the intrusion of carbonatitic magma and subsequent metasomatic processes. The genesis of the deposit was primarily governed by mantle-derived carbonatitic magmatism, with progressive magma differentiation and evolution likely facilitating the enrichment of Fe, REE, Sr, Ba, and Y.
Keywords: Siderite carbonatite, Mg isotope, Whole-rock geochemistry, Igneous carbonatite, Genesis of ore deposit, Bayan Obo
Received: 28 Oct 2024; Accepted: 22 Sep 2025.
Copyright: © 2025 Ren, Jia, Zhou, She, Li and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Hongxiang Jia, cugbjhx@126.com
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