Abstract: The Ray Gulch tungsten skarn and the Eagle Zone intrusion-related gold deposit are associated with the Dublin Gulch intrusion, which forms part of the mid-Cretaceous Tombstone Plutonic Suite. Tungsten mineralization occurs in a roof pendant of hornfelsed Neoproterozoic to Early Cambrian Hyland Group metasedimentary rocks. Five main paragenetic stages include Stage I wollastonite-quartz skarn and later Stage II pyroxene-garnet-scheelite skarn that forms the main tungsten mineralization. Stages III (quartz-scheelite-clinopyroxene), IV (quartz-amphibole-calcite) and V (quartz-K-feldspar-pyrrhotite-molybdenite-arsenopyrite-pyrite-chalcopyrite) are vein related and are volumetrically insignificant (<10 vol. %). Geochemical analysis of the skarn and veins indicates that the deposit lacks gold and bismuth. The earliest veins in the Eagle Zone are similar to Stage V veins at Ray Gulch. Gold at the Eagle Zone occurs in a later sericite-carbonate-bismuth-sulphide vein stage; this stage is critically absent from the skarn. Thus, although tungsten is commonly associated with intrusion-related gold mineralization, it predates gold-bismuth and may occur spatially separate from it.

Authors: Brown, V.S., Baker, T., and Stephens, J.R.

Keywords: mineral potential, Tombstone Plutonic Suite

NTS Mapsheet(s): 106D

Citation: Brown, V.S., Baker, T., and Stephens, J.R., 2002. Ray Gulch tungsten skarn, Dublin Gulch, central Yukon: Gold-tungsten relationships in intrusion-related ore systems and implications for gold exploration. In: Yukon Exploration and Geology 2001, Emond, D.S., Weston, L.W., and Lewis, L.L. (eds.), Exploration and Geological Sciences Division, Yukon Region, Indian and Northern Affairs Canada, p. 259-268.

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