Geology and U-Pb Geochronology of the Qiling Uranium Deposit in the Southern Changjiang Uranium Orefield, South China

The Changjiang uranium orefield, located within the Zhuguang pluton, is a significant granite-related uranium region in South China. However, research on the peripheral uranium deposits in this area remains limited. Enhancing our understanding of uranium deposits in the surrounding regions is essential for guiding prospecting and predictions in the deeper and peripheral parts of the orefield. This study focuses on the Qiling uranium deposit, situated in the southern portion of the Changjiang uranium orefield, through a comprehensive analysis of mineragraphy and U-Pb geochronology of pitchblende. The goal is to better understand the uranium metallogenic processes within the Changjiang uranium orefield. Our findings indicate that the Qiling deposit underwent at least two phases of hydrothermal mineralization. At the 120 m level, the mineral assemblage primarily consists of pitchblende and grayish-white microcrystalline quartz, with a U-Pb age of 76.7 ± 0.2 Ma. This assemblage shows a positive δCe anomaly and lacks a significant δEu anomaly, suggesting that the ore-forming fluids were relatively oxidizing. At the 100 m level, the mineral assemblage includes pitchblende, pyrite, and fluorite, with a U-Pb age of 65.9 ± 0.3 Ma. This level exhibits a negative δEu anomaly and no notable δCe anomaly, indicating more reducing ore-forming conditions. The Qiling uranium deposit is part of the southern extension of the SN-trending ore-bearing structural system and shares a similar genetic mechanism with the Changjiang uranium orefield, highlighting significant potential for deeper mineralization. This study provides crucial evidence for the regional uranium metallogenic model and will aid in the exploration and evaluation of uranium resources.