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TitleA special issue on Archean magmatism, volcanism and ore deposits: Part 2. Volcanogenic massive sulfide deposits preface
AuthorMercier-Langevin, P; Gibson, H L; Hannington, M D; Goutier, J; Monecke, T; Dubé, B; Houlé, M G
SourceEconomic geology and the bulletin of the Society of Economic Geologists vol. 109, no. 1, 2014 p. 1-9, (Open Access)
Alt SeriesEarth Sciences Sector, Contribution Series 20120428
PublisherSociety of Economic Geologists
Mediapaper; on-line; digital
File formatpdf
Lat/Long WENS-180.0000 180.0000 90.0000 -90.0000
Subjectseconomic geology; Archean; magmatism; volcanism; volcanogenic deposits; sulphides; sulphide deposits; nickel; copper; platinum; gold; craton; Precambrian
Illustrationslocation maps; pie charts
ProgramTargeted Geoscience Initiative (TGI-4), TGI-4 Program Coordination
ProgramTargeted Geoscience Initiative (TGI-4), Volcanogenic Massive Sulfide Ore Systems
ProgramTargeted Geoscience Initiative (TGI-4), Gold Ore Systems
Released2013 11 19
AbstractVolcanogenic massive sulfides (VMS) formed episodically throughout Earth's history (Huston et al., 2010) and are, amongst the most common ore deposit types, those that are perhaps the best understood in terms of large scale, geodynamic controls, and processes thanks to years of research on fossil systems and, more recently, on actively forming systems on the sea floor (Hannington et al., 2005 and references therein). The Archean was a prolific period for VMS deposits formation. Approximately eight percent of the global VMS tonnage is of Archean age (Fig. 1A). Proterozoic VMS deposits contain approximately 20 percent of the global VMS tonnage, whereas the Phanerozoic deposits contain 72 percent of the global tonnage due to giant districts such as the Iberian Pyrite Belt, the Urals, the Rudny Altai, and the Bathurst camp (Fig. 1A). The Archean deposits are however slightly richer than the younger deposits (Hutchinson, 1973) as shown by the total metal endowment (Fig. 1B). Interestingly, the Archean deposits, despite representing eight percent of the global tonnage of VMS deposits, contains 10, 12, 12 and 13 percent of the global VMS-related Cu, Zn, Au and Ag, respectively, and only 3 percent of the Pb (Fig. 1C). As suggested by those numbers, and as it is the case for Archean komatiite-associated Ni-Cu-(PGE) and greenstone Au deposits, there are major secular controls on the genesis of VMS deposit (Franklin et al., 1981, 2005; Huston et al., 2010), but there appear to be major craton and district scale controls as well: the Superior Province, the Slave craton, the Yilgarn, and the Pilbara, with 118, 16, 11 and 11 VMS deposits, respectively, host over 90 percent of all Archean VMS deposits (Fig. 2). With its 118 VMS deposits, the Superior Province has by far the largest total accumulation of Archean VMS, representing approximately 76 percent of the total Archean VMS tonnage. More importantly, the VMS deposits of the Superior Province contain over 90 percent of the VMS-related Au of Archean age (Fig. 2). The deposits of the Yilgarn and Slave cratons are comparatively poor in Au. The Slave craton VMS deposits are however strongly enriched in Ag (and Pb) relative to VMS deposits of the other cratons (Fig. 2).
Despite excellent genetic models, finding VMS deposits remains a significant challenge, especially in strongly deformed environments such as Archean greenstone belts. A number of critical factors in the genesis of VMS deposits have been identified in the litterature (Allen et al., 2002, 2011; Franklin et al., 2005; Galley et al., 2007). Among the numerous aspects of VMS deposits that need further research, some are particularly relevant to the Archean, and/or are perhaps more easily tackled in Archean terranes. Some of these aspects are discussed in the papers in this special issue through the study of some of the best examples of VMS deposits or districts, including large, well-exposed deposits, and smaller but rich deposits.
Summary(Plain Language Summary, not published)
This contribution is a preface to a special issue that regroup contributions that discuss some of the geologic controls on the formation and siting of Archean volcanogenic massive sulfide deposits that represent a major source of metals in Canada and elsewhere. The preface introduces and highlights the principal outcomes of the individual papers in the issue. Defining the processes responsible for the genesis of Archean volcanogenic massive sulfide deposits provides information on the evolution of the early Earth. It also provides key information and constraints for developing improved exploration models for this type of deposit. Three aspects are discussed in the preface based on the information presented in the papers in the special issue, including: large scale tectonic controls on the formation of deposits, the geometry and volcanic history of the host successions, and the processes responsible for the enrichment in Au in otherwise base metal-dominant deposits.