Investigation of geological, mineralogical and geochemical properties of the Bezendi (Kelkit-Gümüşhane) Pb-Zn-Cu mineralizations

The Bezendi mineralization was epigenetically formed along with the fractures of the Şenköy Formation. In addition to the vein-type ore structure, disseminated, brecciated, zoned, and banded ore structures are observed in the field macroscopically. Pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite and galena constitute ore minerals, while quartz, barite, and calcite constitute gangue minerals. These features indicate that the Bezendi mineralization has developed a hydrothermal vein type. According to the fluid inclusion studies, two different ore formation phases were determined in the ore, the first being between 342 and 455 ºC and the second between 214 and 326 ºC. The salinity of the fluid inclusions formed in the first phase was 7.1 to 16 wt.% NaCl equ., while the salinity of the fluid inclusions formed in the second phase varies between 2.7 and 6 wt.% NaCl equ. The positive trend observed between the homogenization temperatures and the salinity indicates that the meteoric solution mixed into the hydrothermal solutions. The sulfur isotope results measured from sulfur minerals are between 1.4‰ and -20.5‰, and these values indicate that the hydrothermal solutions possibly originated from magmatic sources, as well as the interaction of basaltic and sedimentary country rocks. According to the results of mineral chemistry analysis, Co was determined up to as high as 7.65 wt.% in the composition of pyrite, arsenopyrite, and pyrrhotite. These high Co values indicate the interaction of hydrothermal solutions with the basaltic host rocks.