Methods for Verifying the Relationship Between Weak Uranium Anomaly and Uranium-Rich Geological Bodies in the Covered Areas of the Erlian Basin, Inner Mongolia

The Erlian Basin, an important research area for sandstone-type uranium deposit exploration in China, is affected by overburden layers, resulting in indistinct characteristics of uranium anomalies in airborne gamma-ray spectrometry (AGS). To harness the potential of AGS, it is imperative to develop effective verification methods that can identify the spatial relationship between weak uranium anomalies and deep uranium-rich geological bodies. This study presents a comprehensive investigation of geophysical and geochemical measurements conducted in four distinct areas. There is a significant positive correlation between the ground gamma spectrometry equivalent uranium (eUGGS) content, soil radon concentration (CRn), geoelectrochemical uranium (UGEC), and metal activity state uranium (UMAS) content directly above and at the edges of uranium-rich geological bodies. When the buried depth of the uranium-rich geological body exceeds 100 m, the eUGGS content above these deep uranium bodies increases by (0.4–1.2) × 10−6 g/g compared to background areas, while the CRn levels at the edges of these bodies increase by more than 5000 Bq/m3, which is 3–5 times higher than the regional average. Meanwhile, the UGEC and UMAS contents show sawtooth-like uranium peak anomalies on their profiles, and their peak-to-background ratio is greater than 5. The verification methods and corresponding interpretation indicators, namely GGS, CRn, GEC and MAS measurements, can quickly reveal the spatial relationship and provide a reliable basis for concealed uranium deposit exploration.