These were used to characterise the trace element composition of each pyrite generation and investigate how trace elements spatially vary. A representative subset of pyrite grains was analysed for trace element contents and distributions by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) using raster grids to create quantitative trace element composition maps. The timing for SEDEX Pb-Zn mineralization was syn- and/or post-late diagenesis (Py2b). characteristics: earliest diagenetic (Py1), early diagenetic (Py2a), late diagenetic Detailed petrographic analyses reveal four pyrite textural varieties, each with distinct morphological. Pyrite-bearing drill core samples were collected from seven drill holes that intersected mineralization and time-stratigraphically equivalent rocks 2 – 3 km away. The MacMillan Pass district in Yukon, Canada, hosts the Tom and Jason sedimentary exhalative (SEDEX) Pb-Zn-Ag-(Ba) deposits. Silver, Pb, Cu, Tl, Zn/Ni and Tl/Co can vector toward mineralization on the drillcore metre-scale, and only Zn can be used as a vector on a larger kilometre-scale. Trace elements in diagenetic pyrite show trends with lateral and vertical distance from intercepted mineralization. Redox sensitive elements (Mo, Ni, Se, Co, Bi) and Sb are less enriched within mineralization, and more enriched in carbonaceous and sedimentary units that likely formed in reduced, organic matter-rich, diagenetic environments. The trace element composition of Py2 within stratiform mineralization is characteristic of pyrite in SEDEX deposits globally. A hydrothermal expression of SEDEX mineralization is recognized in Py2. Py1 contains the highest abundance of trace elements (10s – 1000s ppm), followed by Py2 (10s – 100s ppm), and P圓 (1s – 100s ppm). Three time domains of pyrite growth, early diagenesis (Py1), diagenesis (Py2a, Py2b), and late stage metamorphism (P圓), precipitated pyrite with different trace element signatures. A representative subset of pyrite grains was analysed for trace element contents by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) using raster grids to create quantitative trace element composition maps, in order to characterise the trace element composition of each pyrite generation, and investigate how trace elements spatially vary. ![]() ![]() SEDEX Pb-Zn mineralization was syn and/or post late-diagenesis (Py2b), and pre-metamorphism (P圓). Pyrite-bearing samples from seven drill holes situated within and distal (in time-stratigraphically equivalent rocks, 2 – 4 km away) to mineralization were sampled, and four pyrite varieties are identified, each with distinct morphological characteristics and mineralogical associations: earliest diagenetic and/or chemical sedimentation (Py1), early diagenetic (Py2a), late diagenetic (Py2b), and metamorphic (P圓) were identified. ![]() The Tom and Jason sedimentary exhalative (SEDEX) Pb-Zn-Ag-(Ba) deposits in Yukon, Canada grade 7.4 wt% and 7.0 wt% Zn, and 6.5 wt% and 4.6 wt% Pb, with Zn + Pb tonnages of 15.7 and 10.1 Mt, respectively.
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