| Title | A Middle Devonian basin-scale precious metal enrichment event across north Yukon (Canada) |
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| Author | Gadd, M G ; Peter,
J M; Hnatyshin, D; Creaser, R A; Gouwy, S; Fraser, T |
| Source | Geology vol. 48, no. 3, 2020 p. 242-246, https://doi.org/10.1130/G46874.1  Open Access |
| Image |  |
| Year | 2020 |
| Alt Series | Natural Resources Canada, Contribution Series 20190272 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Yukon |
| NTS | 106; 116A; 116B; 116G; 116H; 116I; 116J; 116O; 116P |
| Area | Richardson Mountains; Ogilvie River; Yukon River |
| Lat/Long WENS | -140.0000 -128.0000 68.0000 64.0000 |
| Subjects | geochronology; stratigraphy; sedimentology; Middle Devonian; mineral enrichment; black shales; biostratigraphy; isochrons; mineral deposits; precious metals; nickel; molybdenum; zinc; platinum;
palladium; gold; sulphide deposits; ore mineral genesis; mineral enrichment; host rocks; bedrock geology; Canol Formation; Canadian Cordillera; Richardson Trough; Road River Group; Nick prospect; Peel River showing; Devonian; Paleozoic |
| Illustrations | location maps; stratigraphic columns; plots |
| Program | Targeted Geoscience Initiative (TGI-5) Volcanic and sedimentary systems - volcanogenic massive sulphide ore systems |
| Released | 2020 01 03 |
| Abstract | Hyper-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. |
| Summary | (Plain Language Summary, not published)
This work applies Re-Os geochronology to metal-rich shale in north Yukon in an attempt to constrain precisely the age of the metal-enriching event. The
data support the hypothesis that enrichment and sedimentation were concurrent at approximately 400 million years ago. This is the first research to constrain the age of mineralization in these deposits. The work is highly relevant to any exploration
geologists and economic geologists interested in gaining a better understanding about how and when these enigmatic deposits formed. |
| GEOSCAN ID | 314981 |
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