STRUCTURALLY CONTROLLED GOLD MINERALIZATION IN CENTRAL NEWFOUNDLAND: IMPLICATIONS FOR GOLD POTENTIAL AND TIMING OF MINERALIZATION
Detailed structural study of a newly discovered gold-bearing quartz vein system along the structural corridor demonstrates that the main ~2 m-wide vein, which extends for ~230 m along strike, cuts deformed polymict conglomerate host and occurs within an oblique left-lateral reverse shear zone that involved a component of north-northeast directed thrusting. An early set of stacked, moderately dipping extensional quartz veins, consistent with left lateral reverse shear, emanate outwards into the country rock from the main vein. A later, more steeply dipping set of extensional quartz veins cross-cut the main vein and the earlier extensional vein set, and are consistent with at least transient phases of horizontal extension. Chalcopyrite and secondary malachite occur locally in the early extension vein set, but are more abundant overall within the later, steeper, extensional vein sets. A nearly conjugate set of steeply dipping extension fractures cross-cut the main vein and the two vein sets. These fractures are typically filled with an assemblage of vuggy quartz-chalcopyrite-malachite±tourmaline±pyrite±hematite±goethite. Field data indicate that the mineralized quartz vein system experienced a progressive structural history characterized by early oblique compressional left-lateral shear and subsequent transient phases of sub-horizontal extension and a final overprint of weak dextral strike-slip.
These results confirm that the quartz vein system preserves a similar structural evolution to a 4.2 Moz gold resource along strike to the southwest at Valentine Lake. Considering the structural setting, is gold mineralization Salinic, Acadian, or younger?