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TitreTesting the relationship between the Llewellyn fault, Tally-Ho shear zone, and gold-mineralization in northwest British Columbia
AuteurOotes, L; Castonguay, S; Friedman, R; Devine, F; Simmonds, R
SourceGeological fieldwork 2017: a summary of field activities and current research; British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2018-1, 2018 p. 67-81
Année2018
Séries alt.Ressources naturelles Canada, Contribution externe 20170305
ÉditeurBritish Columbia Ministry of Energy, Mines and Petroleum Resources
Documentpublication en série
Lang.anglais
Mediapapier; en ligne; numérique
Formatspdf
ProvinceColombie-Britannique; Yukon
SNRC104M/07; 104M/08; 104M/09; 104M/10; 104M/11; 104M/12; 104M/13; 104M/14; 104M/15; 104M/16; 105D/01; 105D/02; 105D/03; 105D/04; 105D/05; 105D/06; 105D/07; 105D/08
Lat/Long OENS-135.5833 -134.0000 60.3667 59.2500
Sujetsgisements minéraux; prospection minière; gîtes épithermaux; gîtes mésothermaux; or; genèse des minerais; minéralisation; contrôles des minerais; contrôles structuraux; géologie du substratum rocheux; caractéristiques structurales; failles; plis; zones de cisaillement; lithologie; roches ignées; roches intrusives; granodiorites; granites; roches volcaniques; rhyolites; roches sédimentaires; roches métamorphiques; marbres; monzonites; amphibolites; mylonites; antécédents tectoniques; métamorphisme; déformation; foliation; linéations; intrusions; plutons; filons rocheux; datation radiométrique; datation au uranium-plomb; datations au zircon; structure de la croûte; gîtes minéralogiques; analyse par spectromètre de masse; Faille de Llewellyn ; Terrane de Nisling ; Suite Métamorphique de Boundary Ranges ; Groupe de Stuhini ; Groupe de Laberge ; Suite Plutonique de Whitehorse ; Terrane de Stikinia ; Terrane de Yukon-tanana; Groupe de Sloko ; Groupe de Carmacks ; Granite de Bennett ; Groupe de Lewes River ; Formation de Povoas ; géologie économique; géologie structurale; tectonique; géochronologie; Phanérozoïque; Cénozoïque; Tertiaire; Mésozoïque; Crétacé; Jurassique; Trias; Paléozoïque
Illustrationsgeoscientific sketch maps; photographs; cross-sections; Concordia diagrams; bar graphs; tables; geological time charts
ProgrammeSystèmes aurifères, Initiative géoscientifique ciblée (IGC-5)
LiensOnline - En ligne
Résumé(disponible en anglais seulement)
The Llewellyn fault represents a significant geological feature in northwest British Columbia. The fault is a southeast-striking, steeply dipping brittle dextral strike-slip structure that overprints 'early' ductile deformation, which is preserved as foliations, lineations, and folds in the host rocks. The Tally-Ho shear zone, Yukon, shares similar early ductile deformation and is overprinted by the Llewellyn fault. In general, the deformation corridor demarcates the eastern limit of metamorphic suites (Triassic and older rocks of the Nisling terrane and Boundary Ranges metamorphic suite) and the western limit of the younger Stuhini (Triassic) and Laberge (Jurassic) groups. Previous work and this study demonstrate that brittle strike-slip deformation along the Llewellyn fault occurred between ca. 56 and 50 Ma. New field observations indicate the early ductile deformation is represented by one foliation (S(main)) along the Llewellyn fault and Tally-Ho shear zone corridor. Two granodiorite intrusions crosscut the early deformation features, and new U-Pb zircon chemical abrasion ID-TIMS results indicate they crystallized at ca. 75 Ma. In the Tally-Ho shear zone, the S(main) is parallel to a foliation in an adjacent granodiorite, mapped as part of the Whitehorse plutonic complex (ca. 120 Ma). In British Columbia, a deformed rhyolite along the Llewellyn fault yielded a preliminary ca. 120 Ma age. Based on these results, we infer that the early ductile fabrics formed before ca. 75 Ma and, potentially, after ca. 120 Ma.
A goal of this study was to establish if the early ductile and late brittle structures represent a crustal-scale, ductile-brittle deformation continuum. If so, could various gold mineralization styles (epithermal, mesothermal, intrusion-related) along the structural corridor be related in time and be part of an orogenic gold mineralizing system? This study demonstrates that, although the early ductile and late brittle deformation share the same space, they developed at least ca. 20 Ma apart and are not part of a structural continuum. This result indicates the various styles of gold mineralization developed during temporally distinct tectonic events.
Résumé(Résumé en langage clair et simple, non publié)
Ce rapport présente les résultats préliminaires d'une etude des relations entre les zones de faille Llewellyn et Tally Ho dans le nord de la Colombie-Britannique et le sud du Yukon. Plusieurs style de minéralisations aurifères sont spatiallement associés à ces zones de faille. Les relations génétiques et temporelles entre ces structures, le volcanisme Eocène et les gisements et indices aurifères sont étudiées à l'aide de travaux de terrain et d'analyses géochronologiques.
GEOSCAN ID306352