| Title | Latest Targeted Geoscience Initiative research results on sediment-hosted base metal sulfide deposits |
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| Author | Gadd, M G ; Peter,
J M |
| Source | AME Roundup 2019, technical sessions abstract guide; 2019 p. 10 |
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20200540 |
| Meeting | AME Roundup 2019; Vancouver, BC; CA; January 28-31, 2019 |
| Document | book |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Yukon |
| NTS | 106E; 106F; 106K; 106L; 116H; 116I |
| Area | Peel River; Nick River |
| Lat/Long WENS | -138.0000 -133.0000 67.0000 65.5000 |
| Subjects | economic geology; geochemistry; Science and Technology; Nature and Environment; ore mineral genesis; ore controls; mineral deposits; base metals; sedimentary ore deposits; sulphide deposits;
volcano-sedimentary ore deposits; nickel; molybdenum; zinc; gold; lead; silver; barium; host rocks; sedimentary rocks; shales; volcano-sedimentary strata; paleoenvironment; isotopic studies; mass spectrometer analysis; platinum group
elements |
| Program | Targeted
Geoscience Initiative (TGI-5) |
| Released | 2019 01 01 |
| Abstract | The authors present results from TGI research on hyperenriched black shale (HEBS) Ni-Mo-Zn-PGE-Au-Re deposits and sedimentary exhalative (SEDEX) Zn-Pb-(Ag-Ba) deposits.
North Yukon is host to several
occurrences of HEBS Ni-Mo-Zn-PGE-Au mineralization, including Nick and Peel River. The redox conditions of marine water columns and sediments are thought to be a primary controlling factor in HEBS formation. To evaluate the ambient paleoenvironmental
conditions, several robust lithogeochemical proxies have been applied to HEBS mineralization and host rocks. Additionally, traditional (sulphur) and non-traditional (molybdenum and thallium) stable isotopes have been measured in host rocks and
mineralization to provide insights into metal and sulphur sources. Collectively, the data reveal that water column conditions during background sedimentation were suboxic. The HEBS sulphide mineralization, however, was precipitated in anoxic to
euxinic conditions at or close to the seafloor in the sub-surface. The molybdenum and thallium isotopic values of the Peel River sedimentary rocks and HEBS mineralization, together with the other bulk paleoredox indicators and REE, indicate that the
molybdenum and thallium were both sourced from seawater. Highly negative sulphur isotope compositions show that biogenically reduced seawater sulphate was the ultimate source of reduced sulphur in the mineralization. Laser ablation-ICP-MS reveals
that pyrite within HEBS is the predominant mineral host for precious metals (palladium, platinum, gold, rhenium). Precious metals are absent in late-stage pyrite-marcasite veins, which effectively constrains the relative age of mineralization to
diagenesis.
Research on SEDEX deposits has focused on pyrite chemistry in the MacMillan Pass zinc-lead-silver-barium district. Four pyrite generations are identified in mineralized and distal, age-equivalent, unmineralized rocks: syn-sedimentary
(Py1), diagenetic (Py2), hydrothermal (Py3), and metamorphic (Py4). Significantly, a SEDEX mineralized element suite (Co-As-Ag-Bi-Tl-Pb-Zn) is recognized within Py3 in the distal (2-4 km), unmineralized samples. This recognition suggests that pyrite
chemistry in MacMillan Pass may be useful in vectoring toward concealed mineralization. |
| GEOSCAN ID | 327599 |
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