Basin Analysis and the Evaluation of Critical Factors for Unconformity-Related Uranium Mineralization, Paleoproterozoic Western Thelon and Otish Basins, Canada
MetadataShow full item record
Two Paleoproterozoic basins, the western Thelon Basin, and the Otish Basin, Canada, were investigated using basin analysis to evaluate critical factors for the formation of unconformity-related uranium deposits. The results serve to guide ongoing exploration at two under-studied uranium prospects in each basin, and help predict whether or not these basins have the potential to host high-grade uranium deposits in other locations. Sequence stratigraphy, in combination with mineral paragenesis indicates that unmetamorphosed basinal sandstones overlying the Boomerang Lake prospect, western Thelon Basin, were compacted and occluded by kaolinite and muscovite during diagenesis, and became diagenetic aquicludes that were unable to effectively conduct uranium-bearing basinal brines. Based on the high δ18O values of basinal and basement-influenced fluids, and the preservation of pre-Thelon-Basin 40Ar/39Ar dates of poorly-crystalline phyllosilicates in the basement rocks, hydrothermal alteration and uranium mineralization must have occurred at low water/rock ratios. This produced uneconomic amounts of U-bearing phosphate that was misidentified as uraninite in a previous report. A significant uranium deposit is unprobable based on the lack of unsupported radiogenic Pb near the prospect. However, intersections of thick, stratigraphically-higher diagenetic aquifers, which are marked by abundant dickite, and structurally-reactivated basement rocks on a different exploration trend remain the most prospective locations for a uranium deposit in the area. At the Camie River prospect, Otish Basin, diagenesis of basinal sediments in thick diagenetic aquifers was associated with fluids that were isotopically similar to seawater-derived basinal brines. The 1721 ±20 Ma Pb/Pb date obtained for Camie River uraninite coincides with intrusions of the Otish Gabbro, which triggered basinal fluid flow in diagenetic aquifers and uranium mineralization throughout the basin. The effects of late hydrothermal, metamorphic, and meteoric fluid events are restricted to fractures and faults. These zones also preferentially host radiogenic Pb and pathfinder elements that dispersed from the prospect, which can be utilized to vector towards additional deposits. The unconformity-type deposit model can be extended to basins as old as 2.0 Ga, as the Otish Basin demonstrates that atmospheric oxygen contents were high enough at this time to allow the evolution of U-leaching oxidizing basinal brines.
Request an alternative formatIf you require this document in an alternate, accessible format, please contact the Queen's Adaptive Technology Centre
Showing items related by title, author, creator and subject.
Controls on lithofacies variability in Late Devonian, Cynthia Basin reefs, Nisku Formation, Western Canadian Sedimentary Basin Johns, Dylan (2012-05-11)The Late Devonian (Frasnian) Nisku Formation in the Western Canadian Sedimentary Basin is a homoclinal ramp composed of four stacked carbonate cycles with reefs in both shallow-ramp and downslope settings. Nisku Formation ...
Intertidal hydrodynamics and basin-scale sediment dynamics in the Minas Basin, Bay of Fundy, and implications for change due to tidal power extraction Ashall, Logan (2015-01-12)Minas Basin in the Bay of Fundy has the world’s largest tidal range and exchanges approximately 110 billion tonnes of water twice a day with tidal currents up to 5 ms-1 through Minas Passage, making it an ideal site for ...
Borron, E. B. (Edward Barnes). (Ontario : Warwick & Sons,, 2014-04-14)