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TitleA Middle Devonian basin-scale precious metal enrichment event across northern Yukon (Canada)
AuthorGadd, M G; Peter, J M; Hnatyshin, D; Creaser, R; Gouwy, S; Fraser, T
SourceGeology vol. 48, no. 3, 2020 p. 242-246, (Open Access)
Alt SeriesNatural Resources Canada, Contribution Series 20200060
PublisherThe Geological Society of America
Mediapaper; on-line; digital
File formatpdf; html
NTS106B; 106C; 106D; 106E; 106F; 106K; 106L; 116; 117
AreaRichardson Mountains; Ogilvie River; Yukon River
Lat/Long WENS-141.0000 -130.0000 70.0000 64.0000
Subjectseconomic geology; stratigraphy; geochronology; paleontology; Nature and Environment; Science and Technology; Middle Devonian; mineral deposits; precious metals; nickel; molybdenum; zinc; platinum; palladium; gold; sulphide deposits; ore mineral genesis; mineral enrichment; host rocks; bedrock geology; lithology; sedimentary rocks; black shales; radiometric dating; geological history; depositional history; sedimentation; mineralization; paleo-sea levels; sea level changes; biostratigraphy; micropaleontology; microfossils; conodonts; fossil zones; Canadian Cordillera; Richardson Trough; Canol Formation; Road River Group; Nick prospect; Peel River showing; hyper-enriched black shale (HEBS); platinum group elements; rhenium; geological contacts; rhenium-osmium dates; Phanerozoic; Paleozoic; Devonian
Illustrationslocation maps; geoscientific sketch maps; stratigraphic sections; plots; biostratigraphic charts
Released2020 01 03
AbstractHyper-enriched black shale (HEBS) Ni-Mo-Zn-Pt-Pd-Au-Re mineralization is geographically widespread across the Richardson trough in northern Yukon (Canada), where it discontinuously outcrops at the regional contact between the Road River Group and overlying Canol Formation. Stratigraphic relationships indicate that the contact is Middle Devonian, but there are no precise age constraints for the HEBS. We apply Re-Os geochronology to HEBS mineralization from two localities that are 130 km apart, the Nick prospect and the Peel River showing, to date directly the age of sulfide mineralization. The Nick prospect yields an isochron age of 390.7 ± 5.1 (2o) Ma, whereas the Peel River showing yields an isochron age of 387.5 ± 4.4 (2o) Ma. Within error, these ages are identical and overlap with the biostratigraphically constrained age of the sedimentary host rocks, indicating that mineralization and sedimentation were coeval. Significantly, the ages of the HEBS overlap those of Middle Devonian Kacák, pumilio, and Taghanic global-scale biotic events which are characterized by eustatic sea-level rise and black shale deposition. Linkage of the Yukon HEBS to one (or more) of these bio-events indicates that sea-level rise may have been requisite to formation of basin-scale HEBS mineralization in northwestern Canada during latest Eifelian and Givetian time.