南岭成矿带大湾铀矿田铀成矿环境与找矿前景

湖南省大湾铀矿田位于南岭成矿带九嶷山杂岩体中段,有利的成矿环境使该地区成为华南重要的产铀区及稀有金属和有色金属矿集区。岩体外接触带寒武系为矿田的主要铀源层之一和成矿有利部位,已探明的铀矿床均产于九嶷山杂岩体中部金鸡岭岩体外接触带。九嶷山杂岩体分别由东、西两个完全独立的岩浆演化中心演化而来,西部岩浆演化中心的金鸡岭岩体与铀成矿作用关系密切,形成了岩浆演化中心、热流体活动中心与矿化中心三位一体的基本构造格局。深大断裂带为成矿流体循环运移提供了通道和热动力来源。铀成矿作用主要发生在晚白垩世早期地应力转向期,矿化与NW向伸展断裂及其相伴的深源热流体有关。岩体接触带为铀沉淀富集的有利地球化学障。重力、航磁及航空γ能谱异常及放射性水化学异常是找铀的重要判据之一。在区域铀成矿环境分析基础上,对该区找矿前景进行了展望。

Uranium mineralization environment and prospecting potential of Dawan ore field in Nanling metallogenic belt

Located in the middle part of Jiuyishan complex pluton,Nanling metallogenic belt,Dawan uranium ore field in Hunan Province is an important uranium-producing and rare metal,nonferrous metal cluster area due to the favourable mineralization environment.The Cambrian is the main uranium source bed and their contact zone to the pluton is the favorable part for mineralization.The uranium deposits which have been explored are all located in the exocontact zone of Jinjiling pluton in the middle part of Jiuyishan complex pluton which is composed of the independent eastern and western magma evolution centers.In the west center,Jinjiling pluton is closely related to uranium mineralization where the trinity geologic setting was formed with magma evolution,hydrothermal fluid action and mineralization.The deep sitted and large faults provide the pathway and thermodynamic source for circulating migration of mineralizing fluid.The uranium mineralization mainly occurred in crustal stress conversion period of Late Cretaceous and related to the tensive NW extending fault and deep originated fluid.The gravity,aeromagnetic,airborne gamma-ray spectrometry anomalies and radioactivity hydrochemical anomaly are important criteria for uranium prospecting.Based on the analysis of regional uranium mineralization environment,the prospecting potential is forecasted.