Composition of some major mineral phases from the Plavica epithermal gold deposit, Eastern Macedonia

Abstract

High-sulphidation epithermal gold has been determined and studied in the Plavica deposit,which is an integral part of the Kratovo-Zletovo volcanic area. Epithermal gold and associated mineralphases have been determined in silicified tuff, secondary quartzite, quartz-pyrite-enargite veins andmainly disseminated within an altered, but mostly silicified volcanic setting. Beside gold within this acidsulphatevolcanic environment was determined the presence of contaminated pyrite, zinc-tetrahedrite,enargite, and certainly seligmanite regularly and commonly present copper association led by chalcopyrite,followed by bornite, chalcocite, covellite, as well as slightly higher temperature associations of arsenopyriteand molybdenite. Most of these accessory sulphide mineral phases within this study were observedunder state of the art polarized optical microscope, and the electron microprobe, which results arepresented in detail in this paper. For illustration we want to emphasize that in pyrite were found increasedconcentrations of copper and zinc and less silver, then enargite with increased zinc concentrations (0.24–7.56 Zn), antimony (0.46–1.33% Sb) and silver (0.09–0.54% Ag) , tennantite with increased iron (0.21–1.55% Fe), zinc (6.24–9.06% Zn) and silver (0.08–0.87% Ag), while within the molybdenite elevatedconcentrations were detected for sulfur and iron.