MINERALOGY AND GEOCHEMISTRY OF THE KOCADAL (TORUL, GÜMÜŞHANE, EASTERN BLACK SEA REGION, TURKEY) Zn-Pb-Ag, Au and Cu MINERALIZATIONS

Abstract

The Kocadal base and precious metal mineralizations are located in the southwest of Gümüşhane province of the eastern Pontide orogenic belt. In the vicinity of the Kocadal mineralization, Gümüşhane granite, lithologies of the Hamurkesen, Berdiga, and Mescitli formations, dacite porphyry and andesite porphyry are present with abundant alluvium. Based on geological, mineralogical, and geochemical features, three mineralization styles have been recognized at the Kocadal area: (i) Mineralizations around Batarya tepe include (ia) Zn mineralization within the conglomerates and sandstones of the Hamurkesen formation and (ib) Zn-Pb-Ag-(Au) mineralization associated with dacite prophyry, (ii) Au mineralization, which occurs to the southwestern of Batarya tepe, and (iii) Cu mineralizations related to quartz veins and veinlets at Gözelerin Dere. Mineralized gravels within the conglomerates contains mainly sphalerite and pyrite, whereas hydrothermal mineralizations associated with porphyritic dacite comprise pyrite and sphalerite, with minor galena, chalcopyrite, pyrrhotite, arsenopyrite, marcasite, fahlerz, pyrargyrite, and proustite. Alteration patterns of hydrothermal mineralization in the field, from older to younger, are classified as: (i) tremolite-actinolite±garnet, (ii) quartz-sericite-chlorite, and (iii) carbonate-quartz. Mineralized gravels within the conglomerates contains mainly sphalerite and pyrite, whereas pyrite, chalcopyrite, and galena are common in quartz veins at Gözelerin Dere. Geostatistical studies based on the results of geochemical analysis of core samples reveal the presence of the distinct element associations for the different styles of mineralizations.