尼日尔特吉达地区砂岩型铀矿综合信息找矿模型

Comprehensive information prospecting model for sandstone uranium deposits in Teguida area,Niger

通过对特吉达地区已知矿床的铀矿找矿模型研究,为该区在矿区外围进一步开展铀矿预测工作提供依据。根据本次物探测量,结合地质、测井等资料,认为:矿体位于下白垩统阿萨乌阿组砂岩中,受区域性断裂控制,常产在古生界隆起的边缘;不同埋深矿体的地球物理场特征各异,但总体表现为车载(地面)伽马能谱测量有铀异常显示,活性炭吸附氡测量有氡浓度异常显示,土壤天然热释光测量有热释光强度异常显示,音频大地电磁(AMT)测量显示矿体位于低阻向中阻变化部位、且靠近中阻一侧。以此为基础,预测了5片铀矿找矿靶区,其中的2片经后期勘查,发现铀矿化(线索)。

Through the investigation of integrated anomalies in known deposits in Teguida,a predictive model for sandstone uranium mineralization was established,which helps to discover buried orebodies. Based on the analysis of geological anomaly,it is concluded that the uranium mineralization lies in Lower Cretaceous Assaousas Formation,controlled by regional faults,and occurs along the edge of the upper Paleozoic uplift. It is also pointed out that the different depths of the orebody have different characteristics of geophysical field,but generally show the phenomenon that uranium anomalies are detected by vehicle or ground gamma spectral survey,radon anomalies detected by activated carbon adsorption of radon,and high value anomalies detected by soil- natural themoluminescence. According to audio frequency magnetelluric sounding,the orebodies are located in the transitional part from low to middle resistivity and close to the middle resistivity. On such a basis,five uranium prospecting targets were predicted,in two of which uranium mineralization（clue） was discovered by the later exploration.