Metallogenic conditions and exploration targets of the sandstone-type uranium deposits in the Husa Basin, western Yunnan:Evidence from the “potential uranium reservoirs” in coalfields

The "potential uranium reservoirs" refer to as the sandstone and conglomerate horizons with the natural gamma-ray values of more than 50 γ (or 3.5 PA/kg, or 150 api, or 12.6 (n-C)/kg-h) in well logs from the coalfield data, which reflects, more or less, special uranium mineralization information in the deeper parts of basins. The present paper focuses on tectonic setting, palaeoclimatology, uranium sources, hydrogeology, lithology, sedimentary facies and uranium potential in the Husa Basin, western Yunnan. Although the Husa Basin is not located in the best favourable exploration area, the dual inversion of tectonics and climates in the Neogene and Quaternary, and the presence of higher natural gamma-ray values and greater thickness may facilitate to the uranium mineralization in the Basin. According to the statistical analysis of the radioactive anomalies and sedimentary characteristics of the "potential uranium reservoirs", referenced to the previous results, the exploration targets are delineated in the first and second members of the Mangbang Formation in the steep slope fan delta facies and ramp alluvial fan facies.