Genesis of Uranium in the Athabasca Region and Its Significance in Exploration

CIM Bulletin, 1970

L. S. BECK, Chief Geologist, Precambrian Geology Division, Saskatchewan Dept. of Mineral Resources, Regina, Saskatchewan

The Athabasca region forms part of the Churchill province of the Canadian Shield and is underlain by an Archean or Aphebian assemblage of rocks that underwent severe metamorphism and granitization during the Hudsonian orogeny (1750-1950 m.y. ago). In places, the eroded orogen is overlain by unmetamorphosed cover rocks (including the Martin and Athabasca formations) of probable Paleohelikian age. Basic dykes cut all the rocks of the region. There are innumerable vein-type pitchblende deposits and many syngenetic occurrences of uraninite in crystalline basement rocks. Evidence is presented to show that pitchblende was emplaced during the final stages of the Hudsonian granitization and followed the crystallization of syngenetic uraninite transitionally. In terms of P-T conditions, the pitchblende deposits belong essentially to Lindgren's mesothermal group. Based on the postulated uranium metallogenesis, the possibilities of finding further deposits of pitchblende and other types of uranium deposits are discussed.
Keywords: Athabasca, Deposits, Fault, Faults, gneisses, lake Athabasca, mylonite, Pegmatite Muscovite, pitchblende, mineralization, Pitchblende, Rock, Rocks