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TitleField observations, mineralogy and geochemistry of Middle Devonian Ni-Zn-Mo-PGE hyper-enriched black shale deposits, Yukon
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AuthorGadd, M G; Peter, J M
SourceTargeted Geoscience Initiative: 2017 report of activities, volume 1; by Rogers, N (ed.); Geological Survey of Canada, Open File 8358, 2018 p. 193-206, https://doi.org/10.4095/306475 (Open Access)
Year2018
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
RelatedThis publication is contained in Rogers, N; (2018). Targeted Geoscience Initiative: 2017 report of activities, volume 1, Geological Survey of Canada, Open File 8358
File formatpdf
ProvinceYukon; Northwest Territories
NTS106D/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
AreaPeel River
Lat/Long WENS-141.0000 -135.0000 66.0000 64.5000
Subjectseconomic geology; geochemistry; mineralogy; stratigraphy; paleontology; Nature and Environment; mineral deposits; mineral exploration; mineral potential; metals; nickel; zinc; molybdenum; sulphides; sedimentary ore deposits; strata-bound deposits; stratiform deposits; ore mineral genesis; mineralization; ore controls; host rocks; pyrite; bedrock geology; lithology; sedimentary rocks; shales; black shales; carbonates; limestones; cherts; concretions; barite; calcite; mass spectrometer analysis; field work; micropaleontology; microfossils; conodonts; biostratigraphy; fossil plants; paleogeography; paleoenvironment; marine environments; continental margins; depositional history; sedimentation rates; organic materials; modelling; bedding planes; diagenesis; Richardson Trough; Mackenzie Platform; Nick Deposit; Peel River Deposit; Eagle Plains Deposit; Monster River Deposit; Canol Formation; Road River Group; Selwyn Basin; ore systems approach; hyper-enriched black shale (HEBS) deposits; platinum group elements (PGE); hyper enrichment; vaesite; x-ray microcomputed tomography; remineralization; plants; Phanerozoic; Paleozoic; Devonian
Illustrationsgeoscientific sketch maps; stratigraphic charts; lithologic sections; geochemical profiles; tables; photomicrographs; 3-D models; photographs; geochemical plots
ProgramKnowledge Management Coordination, Targeted Geoscience Initiative (TGI-5)
ProgramVolcanic and sedimentary systems, Targeted Geoscience Initiative (TGI-5)
ProgramPolar Continental Shelf Program
Released2018 01 19
AbstractHyper-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.
GEOSCAN ID306475