基于ETM^+6–γ示矿信息反演的花山花岗岩铀矿预测

Uranium ore prediction based on inversion of ETM^+6-γmineral information in Huashan granite area

构成铀矿的主要元素——235U核素因衰变释放成因热,使得花岗岩侵入成因的铀矿床(体)周围具有热红外遥感异常。广西桂东花山花岗岩体具有较好的铀矿成矿地质条件,但该区地形复杂,交通不便,利用传统方法开展矿产勘查工作困难很大。为快速圈定该区成矿有利部位,采用Landsat7 ETM+6热红外波段数据,通过数字图像处理技术提取岩体遥感热异常,建立了ETM+6–γ能谱异常场反演模型;运用该模型反演得到了桂东花山花岗岩体的γ能谱异常场分布;在此基础上,根据断裂构造控矿条件及相关地质、矿产资料对γ能谱异常进行筛选,最后在花山花岗岩中圈定出一批铀矿找矿预测区。不仅为下一步实地铀矿勘查找矿工作提供了重要线索,而且再次证明了热红外遥感反演的地温异常信息在花岗岩型铀矿预测中的巨大潜力。

As the main element in the uranium ore deposit,the nuclides of 235U decay to release the factor heat, causing the formation of thermal infrared remote sensing anomalies around the uranium deposit genetically related to granite intrusive body. The Huashan granitic pluton in eastern Guangxi has good geological conditions for generating uranium ore deposits. In the inaccessible environment of harsh terrain,it is difficult to carry out field survey work with traditional methods. Using Landsat7 ETM＋ 6 thermal infrared band data, the authors extracted the remote sensing thermal anomalies of the rock through digital image processing techniques,and established the ETM＋ 6-γ spectrum anomalous inversion model to delineate the γ-spectrum abnormal field distribution of the whole granitic pluton. On such a basis, the authors screened the γ-spectroscopy anomalies according to the ore -controlling fracture structures and related geological and mineral data. At last, a number of uranium ore prospecting areas were delineated in Huashan granitic pluton. The results obtained by the authors not only provide an important clue for the further field prospecting work but also demonstrate the enormous potential of the geothermal anomalies detected through the inversion of thermal infrared remote sensing in the prediction of granite-type uranium ore deposits.