The origin of vein-type copper-lead-zinc deposits Host in Palaeozoic metamorphic rocks at the Southeast Anatolian Orogenic Belt (Küplüce-Adıyaman, Southeastern Turkey)

Abstract

The study area is located around the town of Küplüce between the Çelikhan and Sincik districts (Adıyaman, Turkey). Mineralisations are located at the Southeast Anatolian Orogenic Belt. Despite many differential units, especially in age and lithology, that coexist in the region, mineralisation and alteration are only developed in partly concordant/partly disconcordant veins/veinlets of quartz within chlorite schists, sericite schists, mica schists/mica gneisses, quartz schists and metadiabases of the Palaeozoic Pütürge metamorphics. Pyrite, chalcopyrite and sphalerite are dominant minerals in mineral paragenesis. Chalcocite, covellite and carollite are also found in trace amounts. Quartz, calcite, sericite and chlorite are the gang minerals. Silicification, sericitisation, chloritisation, epidotisation and limonitisation are widespread in limited areas around ore veins. The estimated Co/Ni (1.8–4.3) ratio in pyrites belonging to mineralisation deposits indicates that mineralisation in the region is related to magmatic hydrothermal deposits. In addition, REE (rare earth element) contents of mineralisation deposits in chondrite-normalised diagrams are enriched and show a similar trend to that of chondritic values. This indicates that metals that form mineralisation deposits are related to magmatic rocks. Values of δ34S estimated in the Küplüce region vary between 1.6‰ and 2.34‰. Values of δ34S close to 0 indicate that the sulphur forming the mineralisation is of magmatic origin. In addition, δ18O values vary between 8‰ and 10.8‰ and are consistent with magmatic water. Analyses of the fluid inclusions in quartz samples from mineralisation deposits were performed, and the homogenisation temperature was estimated to be between 90 and 150°C. These temperature values can be explained by the mixing of a solution with surface water. It was determined that mineralisation deposits were vein-type hydrothermal deposits that had developed due to Middle Eocene acidic-intermediate intrusions intersecting Palaeozoic-aged Pütürge metamorphics, and that they exhibited similar characteristics to other mineralisation deposits observed along the Southeastern Anatolian Orogenic Belt.