Stratigraphy of the late Paleoproterozoic Manitou Falls Formation in the vicinity of the McArthur River uranium deposit, Athabasca Basin, Saskatchewan, Canada

The stratigraphy and the sedimentology of the Manitou Falls Formation in the vicinity of the McArthur River uranium deposit in the Athabasca Basin of northern Saskatchewan was investigated as part of the EXTECH IV Multidisciplinary Uranium Deposit Study.; The Manitou Falls Formation is the only unit of the Athabasca Group present in this area. The formation was previously divided into four members, informally named MFa, MFb, MFc and MFd. The present investigation indicates that these can be divided locally into 14 sub-units based on grain-size trends and facies assemblages, supplemented by petrographic and paleoflow studies. The Manitou Falls Formation is interpreted as a product of deposition from ephemeral rivers and of shallow, low to intermediate sinuosity, sand dominated braided rivers.; Thickness changes in the 14 sub-units of the Manitou Falls Formation can be used to illustrate the local kinematic evolution of synsedimentary faults within the basin. This may be important for future uranium exploration, as a close relationship is apparent between the location of re-activated syndepositional faults, permeability pathways created by these faults, and uranium deposits. It may be possible to determine if faults, indicated by geophysical could have been subject to syndeposition activity, using only limited shallow drilling. This may significantly reduce the cost of exploration in deeper parts of the basin.