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TitreVolcanic architecture and precise u-pb geochronology of the Mattagami Mining Camp, Abitibi Subprovince, Quebec:Implications for VMS exploration
AuteurDebreil, J -A; Ross, P -S; McNicoll, V J
SourceAssociation géologique du Canada-Association minéralogique du Canada, Réunion annuelle, Programme et résumés vol. 34, 2011 p. 49-50
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130566
RéunionGAC-MAC-SEG-SGA Joint Annual Meeting 2011; Ottawa; CA; mai 25-27, 2011
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC32E/09; 32E/16; 32F/12; 32F/13
Lat/Long OENS-78.1833 -77.4344 49.8519 49.6083
Sujetsgîtes sulfureux; gîtes volcanogènes; datations au uranium-plomb; Archéen; datations au zircon; roches volcaniques felsiques; rhyolites; volcanisme; tufs volcaniques; datations radiométriques; analyses géochimiques; altération; corrélations stratigraphiques; Ceinture d'Abitibi Greenstone ; Groupe de Wabassee ; géochronologie; stratigraphie; minéraux métalliques; géochimie; Précambrien
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
The Matagami mining camp is located in the northern part of the Archean Abitibi Subprovince in Quebec. Some 19 zinc-rich volcanogenic massive sulphide (VMS) deposits are currently known in the camp. Ten of them have been mined, including the large Mattagami Lake deposit (25 Mt), to produce about 46 Mt of ore so far. Most of the VMS deposits occur along three felsic bands oriented NW-SE to WNW-ESE known as the South Flank, the North Flank, and the West Camp. The geology of the Matagami region is mainly composed of a bimodal volcanic sequence. A number of mafic to intermediate dykes and sills cut the lava-dominated volcanic rocks. Historically, the stratigraphy of the South Flank was divided in two major groups: the Watson Group, including the Watson Dacite and the Watson Rhyolite; and the younger Wabassee Group, composed principally of mafic rocks, with some localized felsic units near the base. These units are separated by a marker horizon called the Key Tuffite, along which most of the VMS deposits have been found. The stratigraphy of the West Camp is less understood, mainly because of a higher grade of deformation, the abundance of intrusive rocks, fewer drill holes, and a lack of outcrop. A PhD project on the reconstruction of the volcanic architecture of the camp is currently underway at INRS. Six new highprecision U-Pb zircon ages on felsic units from the South Flank and the West Camp have been obtained at the GSC. Geochronology can help clarify the relationship between the South Flank and the West Camp, and more specifically test if a time correlation between the two bands is plausible. Further, geochronology can help constrain the temporal evolution of the volcanic activity in the camp. The data shows that the felsic volcanism of the South Flank lasted at most 2.5 m.y. around 2727-2724 Ma, and gives a chronology of emplacement of felsic units along the South Flank. Two varieties of Dumagami Rhyolite from the South Flank have slightly different ages, suggesting that they should perhaps be separated into distinct stratigraphic units. The Key Tuffite, representing a hiatus of volcanic activity, was probably deposited within 0.5 m.y., as shown by the ages of the bracketing rhyolites. Finally, the rhyolite from the footwall of the Caber VMS deposit in the West Camp has an identical age to that of the Watson Rhyolite on the South Flank.