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TitreField observations, mineralogy and geochemistry of Middle Devonian Ni-Zn-Mo-PGE hyper-enriched black shale deposits, Yukon
TéléchargerTéléchargement (publication entière)
AuteurGadd, M G; Peter, J M
SourceTargeted Geoscience Initiative: 2017 report of activities, volume 1; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 8358, 2018 p. 193-206, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
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
ProvinceYukon; Territoires du Nord-Ouest
SNRC106D/11; 106D/12; 106D/13; 106D/14; 106E/03; 106E/04; 106E/05; 106E/06; 106E/11; 106E/12; 106E/13; 106E/14; 116C/09; 116C/10; 116C/15; 116C/16
Lat/Long OENS-141.0000 -135.0000 66.0000 64.5000
Sujetsgisements minéraux; prospection minière; potentiel minier; métaux; nickel; zinc; molybdène; sulfures; gîtes sédimentaires; gîtes stratoïdes; gisements stratiformes; genèse des minerais; minéralisation; contrôles des minerais; roches hôtes; pyrite; géologie du substratum rocheux; lithologie; roches sédimentaires; schistes; ampélites; carbonates; calcaires; chailles; concrétions; barytine; calcite; analyse par spectromètre de masse; travaux de prospection; micropaléontologie; microfossiles; conodontes; biostratigraphie; plantes fossiles; paléogéographie; paléoenvironnement; milieux marins; marges continentales; antecedents de sedimentation; débit de sedimentation; matières organiques; établissement de modèles; plans de litage; diagenèse; Plate-Forme de Mackenzie ; Formation de Canol ; Groupe de Road River ; Bassin de Selwyn ; plante; géologie économique; géochimie; minéralogie; stratigraphie; paléontologie; Nature et environnement; Phanérozoïque; Paléozoïque; Dévonien
Illustrationsgeoscientific sketch maps; stratigraphic charts; lithologic sections; geochemical profiles; tables; photomicrographs; 3-D models; photographs; geochemical plots
ProgrammeInitiative géoscientifique ciblée (IGC-5), Gestion de la connaissance de IGC
ProgrammeInitiative géoscientifique ciblée (IGC-5), Systèmes volcaniques et sédimentaires
ProgrammeProgramme du plateau continental polaire
Diffusé2018 01 19
Résumé(disponible en anglais seulement)
Hyper-enriched black shale (HEBS) deposits are a globally significant repository of base, strategic and precious metals. Some of the best examples of this deposit type are hosted within Devonian shales in northern Yukon. Hyper-accumulations of Ni-Zn-Mo-platinum group elements (PGE) occur in a thin (<10 cm) stratiform and stratabound layer that is widespread geographically (10 000s km2). Despite decades of research, basic questions surrounding the precious metal mineral host(s), age and process(es) responsible for hyper enrichment remain unresolved.
Preliminary laser ablation-inductively coupled plasma-mass spectrometry data for the various base metal sulphide minerals within the HEBS mineralization reveal that vaesite is the principal PGE host (up to 10 ppm Pd, Pt) at the Nick deposit, whereas the fine-grained pyritic matrix hosts PGE (up to 3 ppm Pd and 10 ppm Pt) at the Peel River locality. Conodont biostratigraphy, determined using x-ray microcomputed tomography, gives a Givetian (late Middle Devonian) age that compares well with the regional stratigraphic framework, and is the first ever reported for the HEBS mineralization in Yukon. Finally, recent fieldwork has revealed the occurrence of up to three discrete stacked stratigraphic HEBS layers.
Collectively, these data indicate an ambient paleoenvironment in which highly efficient scavenging of metals and metalloids from seawater operated in tandem with extremely low rates of clastic sedimentation and highly efficient organic matter remineralization. Similar topologies between continental crust-normalized PGE patterns for seawater and HEBS layers support the conclusion that metals and metalloids predominantly originated from ambient seawater.