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TitreGeology, U-Pb geochronology, and geochemistry of the Miocene Pheno Mountain complex, Hoodoo Mountain area, British Columbia
AuteurZagorevski, A; Dziawa, C; Friedman, R M; Mihalynuk, M G
SourceGeological Fieldwork 2012; British Columbia Ministry of Energy, Mines and Petroleum Resources, Paper 2013-1, 2013 p. 115-126
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120328
Documentpublication en série
Lat/Long OENS-131.5000 -131.3333 56.9667 56.8667
Sujetsroches ignées; roches volcaniques; magmatisme; rhyolites; trachytes; Miocène; géochronologie; géochimie; pétrologie ignée et métamorphique; Cénozoïque; Tertiaire
Illustrationslocation maps; photographs; tables; plots
ProgrammeGisements polymétalliques - nord-ouest de la Cordillère canadienne (Yukon et Colombie-Britannique), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
The Pheno Mountain complex comprises rhyolite, trachyte and intrusive quartz feldspar porphyry that form extrusive and hypabyssal
portions of a volcanic complex. A subvolcanic quartz feldspar porphyry with columnar jointing and brecciated margins underlies
petrographically identical volcanic rocks. It yielded a 7.78 ±0.01 Ma U-Pb zircon crystallization age, which is interpreted to constrain
the age of the Pheno Mountain complex. Both the volcanic and hypabyssal rocks are characterized by high Nb/Y, Nb, Y, and Zr
suggesting that they formed in a within-plate setting by fractional crystallization from an alkali basalt parent. These data support
correlation of the Pheno Mountain complex with the Neogene to Quaternary Northern Cordilleran Volcanic Province. However, in
contrast to the coeval Mount Edziza and Level Mountain volcanic centres, magmatism in the Pheno Mountain complex does not appear
to be preceded by construction of a basaltic shield.