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TitreReconnaissance thallium isotope study of zinc-lead SEDEX mineralization and host rocks in the Howard's Pass district, Selwyn Basin, Yukon: potential application to paleoredox determinations and fingerprinting of mineralization
TéléchargerTéléchargement (publication entière)
AuteurPeter, J M; Gadd, M G; Layton-Matthews, D; Voinot, A
SourceTargeted Geoscience Initiative: 2017 report of activities, volume 1; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 8358, 2018 p. 173-191, https://doi.org/10.4095/306474
Année2018
ÉditeurRessources naturelles Canada
Documentdossier public
Lang.anglais
DOIhttps://doi.org/10.4095/306474
Mediaen ligne; numérique
Référence reliéeCette publication est contenue dans Rogers, N; (2018). Targeted Geoscience Initiative: 2017 report of activities, volume 1, Commission géologique du Canada, Dossier public 8358
Formatspdf
ProvinceYukon; Territoires du Nord-Ouest
SNRC105I
Lat/Long OENS-130.0000 -128.0000 63.0000 62.0000
Sujetsgisements minéraux; prospection minière; potentiel minier; zinc; plomb; gîtes sédimentaires; zone d'éruption volcanique; gîtes volcano-sédimentaires; gisements minéraux hydrothermaux; genèse des minerais; minéralisation; contrôles des minerais; oxydation; etudes isotopiques; études des isotopes stables; système hydrothermal; milieux marins; géologie du substratum rocheux; lithologie; roches sédimentaires; mudstones; schistes; grès; chailles; carbonates; dolomites; calcaires; roches ignées; roches volcaniques; couches volcano-sédimentaires; sulfures; roches intrusives; monzonites; granites; roches mères; roches hôtes; cadre tectonique; caractéristiques structurales; failles; modèles; composition en vrac; analyses géochimiques; géochimie du thallium; analyse par spectromètre de masse; analyses de carottes de sondage; micropaléontologie; microfossiles; conodontes; biostratigraphie; Bassin de Selwyn ; Groupe de Road River ; Formation de Duo Lake ; Groupe d'Earn ; Plate-forme de Mackenzie ; géologie économique; tectonique; géochimie; stratigraphie; paléontologie; Phanérozoïque; Mésozoïque; Crétacé; Trias; Paléozoïque; Carbonifère; Dévonien; Silurien; Ordovicien; Cambrien; Précambrien; Protérozoïque
Illustrationsschematic models; bar graphs; tables; geoscientific sketch maps; stratigraphic charts; photographs; geochemical plots; geochemical profiles
Consultation
Endroit
 
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
 
ProgrammeGestion de la connaissance de IGC, Initiative géoscientifique ciblée (IGC-5)
ProgrammeSystèmes volcaniques et sédimentaires, Initiative géoscientifique ciblée (IGC-5)
Diffusé2018 01 19
Résumé(disponible en anglais seulement)
The commonly accepted genetic model for sedimentary exhalative (SEDEX) lead-zinc deposits requires a marine basin with anoxic (no oxygen) and euxinic (free H2S) conditions, in order to provide sulphur to bond with the metals. Recent work on the largest SEDEX district in Canada, the Howard's Pass district, Selwyn Basin, Yukon, has cast doubt on the universality of this model, as the water column may have been suboxic during mineralization. Paleoredox indicators based on bulk geochemical compositions can be contradictory or equivocal. Developments in non-traditional metal stable isotope analysis have shown the potential of certain isotope systems (e.g. molybdenum, uranium, thallium) as paleoredox indicators.
We have conducted a bulk geochemical and thallium isotopic traverse through a mineralized intersection (and immediate stratigraphic footwall and hanging wall) from the Anniv East vent-distal SEDEX deposit, Howard's Pass district. The epsilon-205Tl values range from -7.5 to -4.0 for unmineralized samples and -3.6 to -2.6 for mineralized ones. There is good general agreement between certain redox sensitive elements, venerable redox indicators and epsilon-205Tl for the unmineralized host rocks (reflecting suboxic or oxic conditions for the most negative values). Thus, the application of thallium isotopes as a redox indicator in seafloor hydrothermal deposits in sedimentary (or volcano-sedimentary) settings shows great promise. The heaviest values are for mineralized samples, likely reflecting contributions of isotopically heavy thallium from the mineralizing fluids. Preliminary data indicate that thallium isotopes as a redox indicator in mineralized samples is untenable, but it has the potential to fingerprint sulphides precipitated by various processes.
GEOSCAN ID306474