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

这项研究的目的是确定与不整合相关的铀环境中存在的不同类型的铁氧化物，并识别与铀矿化密切相关的铁氧化物。铁是造岩矿物结构中丰富的化学成分。在富U环境中，Fe和U氧化物共沉淀和/或U将被吸附在Fe氧化物表面，然后逐渐融入到Fe氧化物结构中，从而导致U的沉积。这种稳定性使它们能够保留从地层环境继承的微量元素成分。不同的地质因素，如冰川、河流等，使富铀铁氧化物从风化和侵蚀的赋存岩层中扩散开来，在铀矿床周围形成一种特征的扩散晕。探测到这些光环可以指导勘探地质学家寻找未发现的铀矿。由于铁氧化物不局限于特定的矿床类型或岩性，为了将其用作铀矿勘查的标志，本研究建议在目标富铀环境中表征铁氧化物，然后利用与铀矿化密切相关的铁氧化物的物理、化学和同位素特征来分类松散沉积物中铁氧化物的来源。为了建立在铀矿勘查中使用铁氧化物的标准，本研究建议：1)采集具有代表性的已知加拿大铀矿床(如阿萨巴斯卡盆地的雪茄湖)及其基岩和周围贫瘠岩性的样品作为背景；2)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(LA-ICPMS)等先进分析技术，表征采集样品中铁氧化物的颜色、粒度、结构、矿物组合、微量元素组成和铁、氧同位素地球化学；3)数据集成，并利用多元统计技术进行数据分析，以构建识别指示铀矿化的铁氧化物的判别模型；以及4)建立在铀矿勘查中使用铁氧化物的标准。

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.********