GEOSCAN, résultats de la recherche


TitreNew U-Pb geochronology from the Blake River Group, Abitibi Subprovince, Québec: implications for geological interpretations and base metal exploration
AuteurMcNicoll, V; Goutier, J; Dubé, B; Mercier-Langevin, P; Ross, P; Dion, C; Monecke, T; Legault, M; Percival, J; Gibson, H
SourceArchean volcanism, magmatism and ore deposits; par Mercier-Langevin, P (éd.); Hannington, M (éd.); Gibson, H (éd.); Houlé, M (éd.); Dubé, B (éd.); Monecke, T (éd.); Goutier, J (éd.); Economic geology and the bulletin of the Society of Economic Geologists vol. 109, no. 1, 2014 p. 27-59,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110274
ÉditeurSociety of Economic Geologists
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceQuébec; Ontario
Lat/Long OENS-80.0000 -78.5000 49.0000 48.0000
Sujetsdatations au uranium-plomb; roches volcaniques; gisements minéraux; minéralisation; Archéen; roches volcaniques; roches plutoniques; gîtes volcanogènes; gîtes sulfureux; Groupe de Blake River ; Ceinture d'Abitibi Greenstone ; Mine Horne ; Mine Millenbach ; Mine Amulet ; Formation de Bousquet ; géochronologie; minéraux métalliques; Précambrien
Illustrationsgeological sketch maps
ProgrammeAbitibi IGC-3, Initiative géoscientifique ciblée (IGC-3), 2005-2010
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)
The 2704 to 2695 Ma Blake River Group in the southern Abitibi greenstone belt comprises a well preserved submarine volcanic sequence that hosts a large number of VMS and important Au-rich VMS deposits, including the world-class Horne and LaRonde-Penna deposits. Establishing precise chronostratigraphic control on the VMS deposits within the Blake River Group is critical because numerous distinct events took place within a period of 9 m.y. Nineteen new high-precision U-Pb ages temporally constrain the host rocks of many polymetallic VMS deposits and associated synvolcanic intrusions, demonstrating that these VMS deposits formed throughout the protracted volcanic evolution of the entire group.
Ages on host rocks of the Horne (2702.2 ± 0.9 Ma), Quemont (2702.0 ± 0.8 Ma), and Fabie (2701.9 ± 0.9 Ma) deposits reveal that they are among the oldest VMS deposits in the Blake River Group. The giant Horne Au-rich VMS deposit had already formed when the Cu-Zn deposits of the Noranda mine sequence, including Millenbach and Amulet, were generated at ~2698 Ma and is thus unrelated, consistent with its different volcanological setting and metal content. Large Au-rich VMS deposits of the Bousquet Formation, including LaRonde Penna and Bousquet 2-Dumagami, were formed at 2698 to 2697 Ma and are distinctly younger than the Horne and Quemont deposits. There were, therefore, two major time-stratigraphic intervals within the Blake River Group that were favorable for the formation of Au-rich VMS deposits. Rhyolite hosting the large Bouchard-Hébert VMS deposits yielded an age of 2695.8 ± 0.8 Ma.
Important mineralizing events in the Blake River Group occur at ca. 2-m.y. intervals apart and are associated with major magmatic episodes. Recognition of specific time-stratigraphic intervals for different styles of mineralization and geologic settings is essential to improve exploration models within the Blake River Group and for similar volcanic assemblages elsewhere in the Archean.