Iron oxides/hydroxides from the Athabasca Basin (Saskatchewan) and Kiggavik Camp (Nunavut) unconformity-related deposits as indictors for uranium mineralization

本研究的目的是表征不同类型的铁氧化物存在于不整合相关的U设置，并确定那些密切相关的U矿化。铁是造岩矿物结构中含量丰富的化学成分。在富铀环境中，Fe和U氧化物共沉淀和/或U将吸附在Fe氧化物表面上，然后将逐渐并入Fe氧化物结构中，导致U的沉积。铁氧化物在很宽的氧逸度范围内是稳定的。这种稳定性使它们能够保存从地层环境继承的微量元素成分。富铀铁氧化物在风化、侵蚀围岩中的分散作用可在铀矿床周围形成特征性的分散晕。探测这些晕可以指导勘探地质学家寻找未被发现的铀矿床。由于铁氧化物不限于特定的矿物存款类型或岩性，使用它们作为指示的U勘探，本研究提出了在目标富U设置的铁氧化物的特征，然后使用物理，化学和同位素特征的那些密切相关的U矿化的分类氧化铁颗粒在松散沉积物的来源。为了建立用铁氧化物找铀矿床的标准，本研究建议：（1）从加拿大已知的铀矿床中，如阿萨巴斯卡盆地中的Mesar湖、其岩石和矿床周围的贫瘠岩性中，采集具有代表性的样品作为背景; 2）表征颜色、粒度、纹理、矿物组合、微量元素组成，利用扫描电子显微镜（SEM）、矿物解离分析（MLA）和激光烧蚀电感耦合等离子体质谱等先进分析技术，（3）数据整合，利用多元统计技术建立判别模型，识别指示铀矿化的铁氧化物;（4）建立利用铁氧化物进行铀矿床勘查的标准。

The goal of this research is to characterize different types of Fe oxides present in unconformity-related U settings, and identify those closely associated with U mineralization. Iron is an abundant chemical component in the structure of rock-forming minerals. In U-rich settings, Fe and U oxides co-precipitate and/or U will be adsorbed on the surface of Fe oxides, and then will gradually be incorporated into the Fe Oxides structure that results in deposition of U. Fe oxides are stable over a wide range of oxygen fugacity. This stability enables them to preserve their trace element compositions inherited from formation environments. Dispersion of U-rich Fe oxides from weathered and eroded host rocks by different geologic agents such as glaciers and/or rivers can form a characteristics dispersal halos around U deposits. Detecting these halos can guide exploration geologists to undiscovered U deposits. As Fe oxides are not limited to a specific mineral deposit type or lithology, to use them as indicators for U exploration, this research proposes to characterize Fe oxides in targeted U-rich settings, and then use physical, chemical, and isotopic signatures of those closely associated with U mineralization for classification of the source of Fe oxide grains in unconsolidated sediments. To establish criteria for using Fe oxides in exploration for U deposits, this study proposes 1) collecting samples from a representative number of known Canadian U deposits such as Cigar Lake in the Athabasca Basin, their bedrocks, and barren lithologies surrounding these deposits as background; 2) characterizing color, grain size, textures, mineral associations, trace element compositions, and Fe and O isotope geochemistry of Fe oxides in collected samples using state of the art analytical techniques such as scanning electron microscopy (SEM), mineral liberation analysis (MLA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS); 3) data integration, and data analysis using multivariate statistical techniques to construct discrimination models identifying Fe oxides indicating U mineralization; and 4) establish criteria for using Fe oxides in exploration for U deposits.