Utilizing glacial geology in uranium exploration; Dismal Lakes, Northwest Territories, Canada

A field of uraniferous boulders was discovered in a drift-covered valley west of Dismal Lakes. Glacial geological information was combined with boulder location and trace element till geochemical data to model the dispersal of the boulders; and to predict their likely bedrock source. Uraniferous bedrock was eroded by the last, westward flowing glacial ice to cover the area. The debris was englacially transported and subsequently deposited during subglacial melt-out of ice block(s) stagnating below active ice. The distribution of the boulders forms acrude, westward-opening fan centred on the easternmost boulder and oriented with the last ice-flow direction. The largest uranium values from surface till samples (-2 μm fraction) occur 6.2 km east of the main boulder concentration or 1.5 km east of the first boulder occurrence. The likely bedrock source is 6.0 to 6.6 km east of the main boulder concentration.