Abstract The Cantung, Mactung, and Lened W skarn deposits located in Northwest Territories and Yukon of Canada are part of a large metallogenic belt that contains all major tungsten deposits in western North America. In this study, we evaluate the paragenesis and mineral compositions in these deposits to determine the parameters that control the distribution of high-grade W mineralization in these skarn deposits. The mineral compositions of the Cantung, Mactung and Lened deposits are indicative of reduced fluids (grossular-rich garnet + hedenbergite-rich pyroxene + abundant pyrrhotite), which is characteristic of high-grade W deposits. Local mineral assemblages indicative of oxidizing conditions are observed at Lened, the smallest of the deposits, but are interpreted to be induced by sporadic barite-rich facies within the host rock, and not by an oxidized fluid. Therefore, the redox state of the skarn does not necessarily lessen the exploration potential for the Lened deposit. A correlation between high sulfide and scheelite (CaWO4) contents at Cantung, Mactung and Lened has been reported previously and observed in this study. However, petrographic observations from this study show that scheelite and sulfides precipitated at different times. Scheelite crystallized throughout the entire history of skarn development but peaked at different stages for each deposit. In contrast, sulfides have mainly crystallized as late stage minerals postdating the silicates and scheelite. Variations in the host rock texture and porosity, and therefore permeability, are proposed to be the main factor controlling scheelite-sulfide distribution. This control would be manifested such that areas of greater permeability focused fluid flow, which favored the precipitation of both scheelite and sulfides at different times in the history of the system.

中文翻译：

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加拿大 Cantung、Mactung 和 Lened 钨矽卡岩矿床的共生限制：对品位分布的影响

摘要 位于加拿大西北地区和育空地区的 Cantung、Mactung 和 Lened W 矽卡岩矿床是包含北美西部所有主要钨矿床的大型成矿带的一部分。在这项研究中，我们评估了这些矿床中的共生作用和矿物成分，以确定控制这些矽卡岩矿床中高品位 W 矿化分布的参数。Cantung、Mactung 和 Lened 矿床的矿物成分表明流体减少（富含钙榴石的石榴石 + 富含菱镁矿的辉石 + 丰富的磁黄铁矿），这是高品位 W 矿床的特征。在最小的矿床 Lened 观察到表明氧化条件的局部矿物组合，但被解释为是由主岩内零星的富含重晶石的相诱发的，而不是通过氧化流体。因此，矽卡岩的氧化还原状态不一定会降低Lened 矿床的勘探潜力。Cantung、Mactung 和 Lened 的高硫化物和白钨矿 (CaWO4) 含量之间的相关性先前已有报道，并在本研究中观察到。然而，这项研究的岩相观察表明白钨矿和硫化物在不同时间沉淀。白钨矿在整个矽卡岩开发历史中结晶，但在每个矿床的不同阶段达到顶峰。相比之下，硫化物主要结晶为硅酸盐和白钨矿之后的晚期矿物。主岩结构和孔隙度的变化以及渗透率的变化被认为是控制白钨矿-硫化物分布的主要因素。