Geological, mineralogical, geochemical and genetic investigation of Pb-Zn-Cu ores of The Kabadüz region (Ordu, Northweast-Turkey)

Hydrothermal vein type deposits of Kabadüz (Ordu), are located in the Upper Cretaceous andesitic-basaltic rocks and mostly formed in fault zones along the NW-SE directions. The primary mineral paragenesis of the ore veins are composed of pyrite, chalcopyrite, sphalerite, galena and tetrahedrite-tennantite with quartz and less amount calcite and barite as a gangue mineral. Petrographical studies suggest that the ore veins in the region have similar mineralogical and textural properties.According to the drill core samples of Demiroluk and Haydarlı ore veins, modal abundances of quartz, calcite, apatit, sericite, kaolinite and Mg-chlorite increase whereas K-feldspar, Fe-chlorite, albite and epidote decreases. Considering relative and net mass change calculations, Cu, Pb, Zn, As, Au, Ag ve Ca contents are found to be increase and Na, Ba, K and Rb contents decrease, in the alteration zone. Calculated mass increament is 47.06 and 5.27 % respectively in the alteration zone of Demiroluk and Haydarlı ore veins.Homogenisation temperature and salinity data vary between 180 - 436.1 oC and, 0.4 -14.7 % NaCl, at the fluid inclusions of sphalerite and quartz minerals. Salinity content of the inclusions imply that hydrothermal solutions related to the magmatic sources. Well defined positive correlation between homogenisation temperature and salinity content indicate that meteoric water involved in the hydrothermal solutions.Ore minerals in the veins have similar stochiometric composition. Ni and Co content of the pyrites and Zn/Cd ratio of the sphalerites suggest that hydrothermal solutions related to the acidic type magmatic activity. Magmatic sources have been determined for the sulphur isotope composition of the ore minerals. It is also determined that magmatic and meteoric water involved in the hydrothermal solutions. Based on Pb isotopic composition, ore is related to partial melting of the Lower Crustal-derived granitic intrusions. In such a case, both Pb age data (0.51-1.22 billion year) and sources of the ore deposits indicated that they are genetically linked to Late Cretaceous granitic intrusions.