Mineralogy, mineral chemistry, fluid inclusion, and stable isotope investigations of the Kabadüz ore veins, Ordu, NE-Turkey

Abstract

Hydrothermal vein-type deposits of the Kabadüz region (Ordu, NE-Turkey) are located in Upper Cretaceous andesitic–basaltic rocks and were formed in fault zones along NW–SE direction lines, with thicknesses varying between a few centimetres up to 2m. The primary mineral paragenesis of the many different ore veins consists of pyrite, chalcopyrite, sphalerite, galena and tetrahedrite–tennantite, with quartz and lesser amounts of calcite and barite as gangue minerals. Electron microprobe analyses indicate that the sphalerite and tetrahedrite–tennantite have low Fe contents, with values less than 3.37wt.% and 1.56wt.%, respectively. The very low Ni and Co contents of the pyrites (<0.04wt.%) and the Zn/Cd ratio of the sphalerite (~ avg. 100) indicate that the hydrothermal solutions were related to felsic magmatic activity. The homogenisation temperatures and calculated salinity data vary between 180–436°C and 0.4–14.7 NaCl % eq., respectively. A well-defined negative correlation between the Th and the salinity data suggests that meteoric water was involved in the hydrothermal solutions. Based on the measured first melting temperatures, CaCl2, MgCl2, NaCl and KCl were dominant in the fluid inclusions. The δ34S compositions of the pyrite, chalcopyrite, sphalerite, and galena mineral separates of the investigated ore veins were measured at between 2.14 and −1.47‰, and the oxygen and hydrogen isotope compositions varied between 7.8–8.5‰ and −40 −57‰, respectively. Based on the sulphur, oxygen and hydrogen isotope compositions, magmatic sources were confirmed for the hydrothermal solutions. Taking into account all of the above data and the granitic intrusions around the area, we concluded that younger granitic intrusions were responsible for the ore mineralisation around the Kabadüz region.