ROCK Mount Wright Sulphides23 Jun 2020 18:15
https://dmgeode.com/DepositPortal.aspx?DepositID=2882
A heterolithic breccia occurs adjacent to it, dominated by fragments of basement granite with only a low proportion of rhyolite fragments. In the hypogene zone both breccias (but mainly the rhyolite breccia) are pervasively altered by phengitic sericite and are accompanied by a kaolinite-illite halo. The fine grained, chalk-like alteration has obliterated much textural detail. Gold resides in sulphides and is largely invisible. The sulphides are dominated by pyrite, followed by marmatitic (black) sphalerite, pyrrhotite, chalcopyrite, tetrahedrite and galena. The sulphide distribution is irregular and patchy, very different from typical ‘disseminated’ style. Coarse grains, small masses, groups of crystals, blebs, veinlets, and fracture coatings of sulphides occur in voids found in the altered breccia. The style of gold mineralisation is high-level, sub-volcanic, low-sulphidation, breccia-hosted.