Fluid compositions and P-T conditions of vein-type uranium mineralization in the Beaverlodge uranium district, northern Saskatchewan, Canada

摘要

The Beaverlodge district in northern Saskatchewan is known for "vein-type" uranium mineralization. Most of the uranium deposits are spatially related to major structures, and hosted by ca. 3.2-1.9 Ga granitic rocks (and albitite derived from them) and by ca. 233 Ga Murmac Bay Group amphibolite, all of which are unconformably overlain locally by deformed but unmetamorphosed redbeds of the ca. 1.82 Ga Martin Group, and by the flat-lying ca. 1.75-1.5 Ga Athabasca Group. The uranium mineralization is mainly hosted in fault rocks (breccias) and carbonate +/- quartz +/- albite veins, referred to as breccia-style and vein-style mineralization, respectively, with the latter being the focus of this study. Most of the mineralized veins occur in the basement rocks, although some crosscut the Martin Group. This study examines the field, petrographic, fluid inclusion and C-O isotope characteristics of mineralized and non-mineralized veins from 19 deposits/occurrences as well as from the Martin Group, with an aim to better understand the mineralizing environment and processes.