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TitreFault-mediated melt ascent in a Neoproterozoic continental flood basalt province, the Franklin Sills, Victoria Island, Canada - implications for Ni-sulfide and PGE mineralization
AuteurBédard, J H; Naslund, H R; Steigerwaldt, K; Macdonald, W; Winpenny, A; Hryciuk, M; Hayes, B; Hadlari, T; Dewing, K; Rainbird, R; Girard, E
SourceL'Association géologique du Canada-L'Association minéralogique du Canada, Réunion annuelle conjointe, Recueil des résumés vol. 34, 2011 p. 14
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110063
RéunionGAC/AGC - MAC/AMC - SEG - SGA, Ottawa 2011; Ottawa; CA; mai 25-27, 2011
Documentpublication en série
Mediapapier; CD-ROM; numérique
ProvinceTerritoires du Nord-Ouest
Sujetsroches ignées; magmatisme; tectonique; pétrologie ignée et métamorphique; Protérozoïque; Précambrien
ProgrammeMétaux communs - Île Victoria (T.N-O. et Nunavut), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
The Neo-Proterozoic Franklin Large Igneous Province on Victoria Island, Canada, is characterized by continental flood basalts and a sill-dominated feeder system. Field relationships indicate that there were ephemeral fault-guided transfer zones that allowed magma to jump up-section to form higher-level intrusions. In the corner regions where the magmas move up-section, roof rocks are characterized by unusually wide and intense contact metamorphic haloes, implying significant magmatic throughflow, favourable for Norilsk' type Ni-S mineralization. The geometric constraints suggest that the conduits may have opened episodically, and would be ephemeral, closing when magma pressure waned. The episodic nature of conduit opening events can account for pulsed ascent of crystal slurries, and explains the rarity of exposed feeder conduits in the geological record. Residual oxide-sulfide-saturated fluids expelled from the feeder sill during roof subsidence would have been channelled by the fault, and reacted with contact-metamorphosed roof rocks to form skarns.