Türkiye Jeoloji Bülteni

A typical example of allochtonous Cyprus type copper mineralizations: Derdere mineralizations

Abstract: The studied mineralizations are situated at 10 km south of Çüngüş (Diyarbakır) and 500 m north of Derdere Village. The research area contains three different Hthologies. These are Jurassic-Lower Cretaceous Koçali Complex, Eocene Midyat Group and Lower Miocene Fırat Formation. The Koçali Complex which bears the mineralizations, presents a cross section ofophiolitic suite, while the position of ophiolites is upside down and contains serpentinite, gabbro, diabase, spilitic basalt and pelagic sediments.The mineralizations are placed within the top units of the ophiolitic suite and inside the spilitic basalt. The mineralized bodiesare either lense shaped or stratiform. The position of ore is N50°W/55° NE, 4-5 m thick and around 50-60 m long. The observed oreminerals are pyrite, chalcopyrite, sphalerite, covellite-chalcocite and baryite.The chemical analyses of ores show that the Cu and Zn contents are promising. It is also observed that there are good positive correlations between Cu-Mn, Cu-Fe, Cu-Zn, Au-As, Au-Sb, Au-Ag, Ba-Mg; but negative correlations between Cu-Ag, Fe-Cd, Cu-Cd.The Derdere mineralizations which are placed in the upper levels of ophiolitic suite which itself is a section of oceanic crust,exhibit the general features of Cyprus Type massive Sulphide Ores. These mineralizations are quite different from the Eocene Cumineralizations of Southeastern Thrust Belt; studied mineralizations are Jurassic-Lower Cretaceous aged and openly situated inophiolitic litholigies (Eocene aged Cu mineralizations do not show any open relationship with ophiolites).