The Atlin Goldfields property is underlain primarily by Mississippian to Triassic-aged volcanic and sedimentary rocks of the Cache Creek Complex, including quartz-carbonate-mariposite-altered ultramafic and mafic rocks (‘listwanite’), which are commonly associated with the gold mineralization in the region.
Proximity to a mineralized source
The Cache Creek Complex is intruded by the Middle Jurassic Fourth of July batholith and the Late Cretaceous Surprise Lake batholith.
Placer mining from the Atlin creeks produces mostly sharp-edge, “hackly” gold nuggets, indicating proximity to a mineralized source. Recent studies have shown that mafic and ultramafic rocks are not the only source of Atlin’s placer gold. Sedimentary rocks of the Cache Creek Complex (specifically graphitic and quartz-rich phyllitic bedrock) are now known to host gold-bearing quartz veins in the region (Mihalynuk et al. 2017).
The detailed geochemical research conducted on select Atlin gold nuggets has revealed the presence of tin (cassiterite) and thorium (thorite) mineral intergrowths. These intergrowths are rich in Sn, Th, U, Mo, W, and F, indicating a potential association with the Sn-U-Th-Mo-W-F rich Surprise Lake batholith.
The findings suggest the presence of both orogenic gold and intrusion-related gold systems on the Atlin property. This implies that there are multiple sources of gold mineralization, increasing the potential for diverse and valuable gold deposits within the area.
The detailed geochemical research conducted on select Atlin gold nuggets has revealed the presence of tin (cassiterite) and thorium (thorite) mineral intergrowths. These intergrowths are rich in Sn, Th, U, Mo, W, and F, indicating a potential association with the Sn-U-Th-Mo-W-F rich Surprise Lake batholith.
