Exploring sandstone-hosted uranium deposits in coal-bearing basins using geophysical methods: A case study of the east-central Erlian Basin

Background Sandstone-hosted uranium deposits, critical to the uranium resources growth in China, are extensively distributed in continental and marine-continental transitional sedimentary rocks. Currently, the exploration and research on these deposits in China focus primarily on the Meso-Cenozoic sedimentary basins in the northern regions. Objective and Methods‌ The Erlian Basin exhibits the coexistence of uranium, coals, and oil. This study investigated the east-central part of this basin using multiple geophysical data, including regional gravity survey, aeromagnetic survey, and airborne radioactivity survey (ARS). Furthermore, six 2D seismic profiles totaling 130 km in length were deployed, and instantaneous soil radon measurement as employed. Accordingly, this study analyzed the geological characteristics and geophysical responses of key ore-controlling factors of sandstone-hosted uranium deposits in the region and constructed a prospecting prediction model, aiming to provide technical support for uranium exploration in coal-bearing regions. Results Gravity inversion revealed the relationships of the uplift and depression structures in the basement with uranium enrichment, while aeromagnetic survey and ARS determined denudation-related provenance areas and uranium migration patterns. Specifically, the Sonid and Bayinbaolige uplifts were identified as two major provenance areas using regional gravity, magnetic, and aeroradiometric data, with the material supply boundaries delineated. Besides, uranium-bearing sand bodies and the structural skylights of denudation-related provenance areas were delineated using 2D seismic profiling. Through validation of radon anomalies by drilling, this study delineated a new uranium metallogenic belt measuring about 20 km in length and 1‒3 km in width in the southern Manite Depression. Conclusions Regional gravity, magnetic and aeroradiometric data provide an important basis for the analysis of the macroscopic metallogenic setting, while 2D seismic survey and radon measurement excel in the localization of uranium-bearing sand bodies and the identification of mineralization anomalies. This study, achieving a multi-scale fusion of geophysical methods, lays a robust foundation break through in mineral exploitation of sandstone-hosted uranium resources in coal-bearing basins.