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TitleGeodynamic influences on the genesis of Archean world-class gold-rich VMS deposits: examples from the Blake River Group, Abitibi greenstone belt, Canada
AuthorMercier-Langevin, P; Hannington, P; Dubé, B; McNicoll, V; Goutier, J; Monecke, T
SourceGeological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Programs with Abstracts vol. 36, 2013 p. 144-145
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20130545
PublisherGAC MAC
MeetingGAC-MAC 2013; Joint annual meeting of Geological Association of Canada and Mineralogical Association of Canada; Winnipeg; CA; May 22-24, 2013
Mediaon-line; digital
File formatpdf
NTS32D/03NE; 32D/06; 32D/07
AreaRouyn Noranda; Lac Chassignolle; Malartic
Lat/Long WENS -79.5000 -78.5000 48.5000 48.1667
Subjectseconomic geology; igneous and metamorphic petrology; mineral occurrences; mineral deposits; mineral potential; mineralization; gold; volcanogenic deposits; sulphides; sulphide deposits; lithogeochemistry; greenstone belts; greenstones; igneous rocks; volcanic rocks; tholeiites; basalts; andesites; lithostratigraphy; Archean; Abitibi Greenstone Belt; Laronde Penna Deposit; Blake River Group; Bousquet Deposit; Doyon Deposit; Precambrian; Proterozoic
ProgramTargeted Geoscience Initiative (TGI-4), Volcanogenic Massive Sulfide Ore Systems
AbstractSix of the world's richest and largest gold-rich volcanogenic massive sulphide (VMS) deposits are located in the 2704-2695 Ma Blake River Group (BRG) of the Abitibi greenstone belt, including the two largest ever found (Horne: 54 Mt, 328 t Au, and LaRonde Penna: 80 Mt, 290 t Au), suggesting district and deposit-scale primary geological control(s) on the gold enrichment in VMS deposits. The gold-rich VMS deposits of the BRG are found in distinctly different volcanic and structural settings from other “conventional” VMS deposits in the district. The ~2701 Ma Horne gold-rich deposit is separated in time and space from the ~2698 Ma Noranda Mine Sequence Cu-Zn VMS; it is located in the southern part of the Noranda camp in fault-bounded structural blocks separated from the slightly younger Cu-Zn deposits. The Bousquet Formation, which hosts the ~2698 Ma LaRonde Penna deposit, was coeval with the volcanic rocks that host the Cu-Zn VMS of the Noranda Mine Sequence but is distinguished by its transitional to calc-alkaline affinity and dominantly felsic composition. The Bousquet Formation is thought to have been formed in a volcanic complex at the periphery of the central part of the BRG, possibly in an area characterized by a thicker crust undergoing early extension and closer to an inferred arc (immature or early arc-rift stage). Recent dating in the BRG indicates that Horne also formed during an episode of early extension-subsidence and transitional felsic volcanism at Noranda (2702-2701 Ma). Extension, VMS-related hydrothermal activity and transitional to calc-alkaline volcanism moved away from the central part of the BRG, and by 2698-2697 Ma, at which time Horne had already formed, the Cu-Zn deposits of the Noranda Mine Sequence were being deposited in the more mature, tholeiitic to transitional, mafic-dominated extensional setting. Despite obvious limitations of reconstructions of Archean volcanic complexes, analogies can be made with the architecture and evolution of modern volcanic arcs such as those formed along the western Pacific. The BRG gold-rich VMS deposits were formed during incipient extension episodes at different times and places in a setting that is thought to have been transitional between arc and back-arc regions. Specific time-stratigraphic intervals related to arc extension are viewed as an important guide to exploration for gold-rich VMS in ancient volcanic belts. The concentration of gold-rich VMS deposits in the eastern BRG highlights a region with favourable gold “heritage”, where gold deposits of multiple ages and styles are formed throughout the evolution of the belt.