Gold mineralization in the Three Bluffs gold deposit, Committee Bay greenstone belt, Nunavut

The Three Bluffs gold occurrence is hosted by polydeformed and metamorphosed auriferous iron formations of the Neoarchean Prince Albert group located in the Western Churchill Province, Nunavut. The supracrustal rocks at Three Bluffs consist of a thick sequence of petite, semipelite, and psammite iron formation is variably interbedded within these metasediments.Results of U-Pb monazite dating indicate a major metamorphic event at ca. 1780 Ma. A subordinate population of monazite dates suggests a precursor event at ca. 1811 Ma. Rhenium-osmium analysis of arsenopyrite record a recrystall zation age of ca. 1780 Ma as well as a possible mineralization age of 1820 Ma. Deformation fabrics, geochronology, and the overall geometry of the mineralized zone, suggest that the gold mineralization occurred pre- to syn-1812 Ma followed by peak metamorphism and deformation at ca. 1780 Ma and was followed by a prolonged thermal cooling.