Mineralogical and geochemical investigation of alterations in Yeşi̇lbağlar-Kaban (Olur-Erzurum) region

The Alpine Orogenic Belt, possessing number of porphyry type copper-molybdenite-gold deposits, starts from the eastern Europe extending through Turkey-Caucasus till Iran and Afghanistan. The study area is situated in the Eastern Pontides that is the part of Eastern Anatolian Metallogenic Belt. In this study, the alteration zones within the Yeşilbağlar, Kaban and Köprübaşı localities have been selected and FT-IR, XRD, mineral chemistry, whole rock chemistry and isotope geochemistry analyses were carried out for the host rocks and mineralizations. Mineralization within the alteration zones are observed in altered Eocene dacitic volcanic rocks as disseminated, stockwork and joint-filling. Mineralization is characterized by pyrite, chalcopyrite, sphalerite, galenite and pyrrhotine. Whereas the gang minerals are of quartz, calcite and barite. Clay, sulphide, sulphur, carbonate, silicate and oxide phases within the alteration zone were determined by the FT-IR and XRD analyses. Sulphur source for the mineralization is established by the S-isotope analysis. Whole rock geochemistry suggests that the Eocene volcanic rocks were formed above a subduction zone along the active continental margin. Sr and Pb isotope analyses suggest that alteration zones were fed by subduction-related melts, originating from the combination of mantle and crust. The field and petrographical studies as well as the geochemical analyses show that the alteration zones within the Yeşilbağlar, Kaban and Köprübaşı regions can be well correlated with the porphyry type mineralizations along the Alpine Orogenic Belt.