Publication Type:Book Chapter
Source:Targeted Geoscience Initiative 4: Contributions to the understanding of Precambrian lode gold deposits and implications for exploration, Geological Survey of Canada, Volume Open File 7852, p.1-24 (2015)
The TGI-4 Lode Gold project, which comprises numerous site-specific and thematic research activities, covers the entire spectrum of crustal settings for lode gold deposits, from orogenic banded iron formationhosted and greenstone-hosted quartz carbonate vein-type gold deposits formed deep in the crust (>5 km), to intrusion-related deposits that are formed at shallower crustal levels (~2-5 km), and to deposits formed at or near the seafloor. Herein we synthesize a number of important project contributions that have significant implications for on-going mineral exploration for hidden deposits. Among the key findings is a newly established link between major faults, their early evolution, syntectonic magmatism and synorogenic sedimentary basin evolution, and gold metallogenesis in various greenstone belts. The revised model incorporates a phase of tectonic extension-a distinct feature recognized in gold-rich settings worldwide-that is applicable to mineral exploration targeting across the Canadian Shield. Importantly, the simultaneous multidisciplinary study of a number of large banded iron formation-hosted gold deposits and districts allows for the development of a unifying genetic model for such deposits that integrates critical structural, stratigraphic, hydrothermal, and metamorphic elements. Several key features that are common to all of the studied deposits, but elements specific to dominantly banded iron formation-hosted gold deposits or to deposits that are only partly hosted in banded iron formation, were also established. The Lode Gold project also bridges a major knowledge gap by characterizing a spectrum of "unusual" or "atypical" gold deposits in the Superior Province. The new and revised models incorporate synvolcanic as well as pre-deformation and synorogenic synmagmatic or intrusion-related gold deposits that represent a large part of the newly discovered resources in the Canadian Shield in both "brownfield" and "greenfield" exploration environments.