Meveralogical and genetical investigation of barite deposits around the Karamustafa and Haskoy areas

SUMMARY MINERALOGICAL AND GENETICAL INVESTIGATION OF BARITE DEPOSITS AROUND THE KARAMUSTAFA AND HASKÖY AREAS. This syudy aims at determining the mineralogy and genesis of the vein type barite deposits located to the southwest of Gümüşhane. The basement in the area is made up of Permian-Carboniferous aged granitoid rocks which are disconformably overlain by volcano-sedimentary series of Liassic age. Conformably overlying these are the limestone of Dogger-Malm which are followed with an angular unconformity by the Upper Cretaceous flysh intercalated with volcanics. All these lithologies are intruded by the Eocene aged andesitic lavas and pyroclastics. The youngest units are alluvium and slope debris of Quaternary age. The barite deposits are structurally controlled and occur as veins and veinlets within the granitoids and volcano-sedimentary series or along their contacts. According to the XRF analyses, the barite contains 0.9-1.7% SrO and 40-66% BaO. Fluid inclusion studies have been carried out on primary and secondary inclusions in the barite crystals. These inclusions have homogenization temperatures between 170 to 220 °C. As a result, it may be concluded that hydrothermal solutions responsible for Ba deposition is associated with the volcanics of Liassic age. The hydrothermal fluids which gave rise to barite deposition may also have been more enriched in Ba through dissolving it from feldspar of the monzogranite while passing through its fractures. In other words, monzogranite may also have played a part as a secondary source of Ba. Key Words: Karamustafa - Hasköy (Gümüşhane), Hydrothermal barite veins, Mineralogy, Geochemistry and Genesis. VI