The investigation of Ünlüpinar (Kelki̇t-Gümüşhane) Eylence yayla Pb-Zn-Cu±Au mineralization as geological, mineralogical and genesis

The investigated area covers the immediate surrounding of Eylence Yayla and Emirinkomu, Ünlüpınar (Pekün) town of Kelkit County located south of Gümüşhane Province In this study, 1/25000 scaled geological map of the region and the detailed 1/10000 scaled mining geology map of the areas including the mineralization were prepared. Kurtoğlu Metamorphics, Şenköy Formationand Köse Granitoidarelocated in the study area. The geologic unit of the area investigated in detail and its near surrounding comprise the andesite-basalt and their pyroclastics of Early-Mid Jurassic age Şenköy Formation. The Zn-Pb-Cu ± Au mineralization located in Eylence Yayla site is completely settled into the N20E striking-fault lines within andesites belonging to Şenköy Formation. While classifying age-Liassic volcanic rocks, it is seen that by using Nb/Y - Zr/TiO2 diagram created with immobile elements, the samples taken from Senkoy Formation are concentrated at the border of the andesite-basalt and andesite.Liassic volcanic rocks include in plagioclase, clinopyroxene and Fe-Ti oxide minerals. According to the analysis results of the mineral composition, it is determined that plagioclase have a composition with bytownite (An73-78), labrador (An51-64) andandesine (An32-42), clinopyroxene have a composition with augite and clinoenstatite (Wo33.418-39.358En18.220-27.230,Fs38,565 to 61,792) and Fe-Ti oxides have a composition with titano-magnetite. To reveal the mineralization assemblages in the study area, the polished samples, which prepared from systematic samples taking from the investigated area, were examined under the oremicroscopy. The paragenesis of the mineralization is determined, according to the order of occurrence, as pyrite, chalcopyrite, sphalerite, galena, gold, quartz and calcite. The hematitization, limonitization and sulfurization are identified alteration types, based on the observation smade on the field. According to the results of the fluid inclusion studies, the formation temperature of mineralization changes between 80-280 C; and based on the sulphur isotope thermometer analysis, the average formation temperature of mineralization is determinedas 264 C. The origin of mineralization is surely decided magmatic, according to the results of sulphur, carbon and oxygen isotopes analyses. Keywords: Gold, Stable isotope, Kelkit, Lead-Zinc, Fluid inclusion