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TitreA special issue on Archean magmatism, volcanism and ore deposits: Part 2. Volcanogenic massive sulfide deposits preface
AuteurMercier-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, https://doi.org/10.2113/econgeo.109.1.1
Année2014
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120428
ÉditeurEconomic Geology, Society of Economic Geologists, Inc.(SEG)
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.2113/econgeo.109.1.1
Mediapapier; en ligne; numérique
Formatspdf
Lat/Long OENS-180.0000 180.0000 90.0000 -90.0000
SujetsArchéen; magmatisme; volcanisme; gîtes volcanogènes; sulfures; gîtes sulfureux; nickel; cuivre; platine; or; craton; géologie économique; Précambrien
Illustrationslocation maps; pie charts
ProgrammeCoordination de IGC-4, Initiative géoscientifique ciblée (IGC-4)
ProgrammeÉtude des gîtes de sulfures massifs volcaniques, Initiative géoscientifique ciblée (IGC-4)
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
Volcanogenic 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.
Résumé(Résumé en langage clair et simple, non publié)
Cette contribution est un préface à un numéro spécial qui regroupe des articles discutant des contrôles géologiques dans la formation et la localisation de gisements de type sulfures massifs volcanogènes d¿âge archéen qui représentent une source de métaux au Canada et ailleurs. La préface met en lumière les principaux extrants des articles formant le numéro spécial. Une compréhension améliorée des processus responsables de la formation de sulfures massifs volcanogènes archéens apporte des informations supplémentaires sur l¿évolution de la Terre au début de son histoire. Cela permet d¿améliorer les guides d¿exploration pour ce type de dépôt. Trois aspects sont particulièrement soulignés dans la préface: les contrôles tectoniques à grande échelle sur la formation et la localisation des gisements, la géométrie et l¿histoire volcanique séquences hôtes, et les processus responsables de l¿enrichissement en or des gisements.
GEOSCAN ID292319