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TitreGeology of the Warrenmac gold-rich polymetallic massive sulphide lens, Westwood deposit, Abitibi, Québec
AuteurYergeau, D; Mercier-Langevin, P; Malo, M; Dubé, B; Bernier, C; Savoie, A; Houle, N; Savard, P
SourceQuébec exploration, abstracts of oral presentations and posters ; Québec Ministère de l'énergie et des ressources, Documents divers 2011-04, 2011 p. 39
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130585
RéunionQuébec exploration; Québec; CA; Novembre 21-24, 2011
Documentpublication en série
Lat/Long OENS-78.5000 -78.0000 48.2500 48.0000
Sujetsroches volcaniques; gisements minéraux; minéralisation; Archéen; gîtes volcanogènes; gîtes sulfureux; altération hydrothermale; gisements minéraux hydrothermaux; minéraux métalliques; Précambrien
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
The Westwood deposit, located 35 km east of Rouyn- Noranda in the Abitibi Subprovince, is one of the recent major discoveries in Canada, with 3.43 million ounces of gold resources. The ore deposit is located in the Doyon- Bousquet-LaRonde mining camp, in the eastern part of the Blake River Group. More specifi cally, mineralized zones are hosted in volcanic rocks of the Bousquet Formation, which forms a thin homoclinal sub-vertical sequence trending east/ west and facing south that possibly represents the remains of a stratovolcano. The Bousquet Formation is divided into a lower member composed of tholeiitic to transitional mafi c to felsic volcanic rocks, and an upper member composed of transitional to calc-alkaline intermediate to felsic volcanic rocks. The study area is strongly deformed and metamorphosed to the upper greenschist facies. The ore deposit consists of three distinct mineralized envelopes that are, from north to south: Zone 2 Extension, the North Corridor and the Westwood Corridor. Zone 2 Extension is characterized by centimetre- to decimetre-scale pyrite-rich gold-bearing quartz veins. The North Corridor on the other hand, consists of centimetre- to decimetre-scale sulphide-rich gold-bearing quartz veins, with semi-massive to massive sulphide veins. Both of these mineralized envelopes are slightly discordant. Finally, the Westwood Corridor is composed of conformable gold-bearing massive to semimassive sulphide lenses. The Warrenmac lens, characterized by massive sulphides consisting of pyrite and sphalerite with minor amounts of chalcopyrite and galena overlain by a strongly transposed stringer zone, is a good example of the mineralized lenses in the Westwood Corridor. The footwall of the ore lens consists of fragmental dacite overlain by massive andesite, whereas the hanging wall shows a variable composition. The main alteration minerals associated with this lens are Mn-rich garnet, Mg-rich chlorite, and sericite. The main objective of this study is to characterize the formation and document the potential link between gold-rich volcanogenic massive sulphides lenses (e.g., Westwood Corridor) and mineralized zones occurring in the form of quartz and sulphide veins (e.g., Zone 2 Extension, North Corridor), based on a study of the Westwood deposit. This area also provides an opportunity to study Archean magmatic-hydrothermal systems. Knowledge derived from this study may contribute in developing better exploration vectors for this type of deposit in the Abitibi and elsewhere, in other ancient greenstone belts.