Diagenetic bournonite in elastic ores of the Safyanovskoe copper-zinc massive sulfide deposit, the Middle Urals
Safina N. P., Ayupova N. R.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2017. V. 146. N 2. P. 73-87
Peculiarities of the Sb behavior (including formation of new accessory mineral assemblages) in submarine supergenesis were studied on example of clastic ores of the Saf’yanovskoe VMS deposit. Seafloor alteration of fine-clastic sulfide-carbonaceous sediments led to formation of pyrite framboids, crystals and nodules, sphalerite, chalcopyrite, fahlore, bournonite, famatinite, enargite and galena, as well as associated covellite, anglesite and rutile. Bournonite has been found in these massive sulfide ores for the first time. It has intergrowths witn pseudomorphic sphalerite, Zn-bearing (2—6 wt % Zn) and low Sb (up to 0.3 wt % Sb) enargite, famatinite and covellite. Bournonite crystals, 20—50 mm in size, are characterized by twinned structure with tabular individuals as thick as 2—3 mm. The mineral contains admixtures of Fe (0.3—0.8 wt %) and Zn (0.1—0.7 wt %). It is suggested that bournonite was formed in the course of increasing diagenetic «maturity» of sulfide 1àyårs with elements extracted from primary galena- and fahlore-bearing ore clasts and their further concentration in form of new sulfides.
Key words: bournonite, clastic ores, submarine supergenesis, Saf’yanovskoe VMS deposit, the Middle Urals.