Metal source and the origin of the Darıderesi Pb-Zn (Ag) veins in the Balya Mining District, NW Türkiye: constraints from ore mineral chemistry, fluid inclusions and S-Pb isotopic signatures

Abstract

ABSTRACTThe Darıderesi mineralisation was recently discovered in the Balya district, which hosts Pb-Zn (Ag) deposits including Arı Mağara-Balya Main and Hastanetepe-Balya North. Darıderesi is a structurally controlled hydrothermal and associated replacement mineralisation hosted in the shale-mudstone and carbonaceous horizons within the Karakaya Complex. The mineralisation was formed in three main stages as pre-ore calc-silicate alteration, main ore, and supergene alteration. The substages of the sulphide-sulphosalt mineralisation can be summarised as: pyrite-arsenopyrite galena, sphalerite, ferrokesterite, chalcopyrite, fahlore group and geocronite-jordanite solid solution series members, xanthoconite, pyrargyrite and goldfieldite. Fluid inclusion studies indicate that both boiling and fluid mixing were the most effective processes causing the precipitation of sulphides and sulphosalts. Along its pathway, fluid–rock interaction coupled with decreasing temperature evolved the fluid to a lower sulphur and oxygen fugacity and nearly neutral to weakly alkali state which promoted the precipitation of base metal and the following silver-bearing sulphides and sulphosalts. The lead isotope composition of sulphides implies that lead was essentially derived from Oligo-Miocene magmatic rocks in the region with some interaction with basement rocks. The similarity of the lead and sulphur isotopic compositions between Darıderesi and Balya deposits suggests that they may relate to the same magmatic source.

Keywords

• Balya
• Biga Peninsula
• Pb-zn vein
• sulphide and sulphosalts
• Pb and S isotopes