Geodynamic processes affected the formation of theMadenköy (Niğde) subterranean plaser gold deposit

The study area is located in Madenköy (Niğde) and its surroundings, at the northeastern end of the Bolkar Mountains, which form the eastern part of the Central Taurus Mountains. In this region, there are lithostratigraphic units grouped as rocks belonging to the Alihoca ophiolitic complex (Mesozoic) and to the carbonate Bolkardağ platform (Cenozoic) rocks. There are primary sulphide mineralizations associated with the quartz porphyry veins (dykes and sills) within the carbonate rocks dated as Lower Eocene (49-54 My), and oxidized secondary Au- Ag-Zn-Pb ore enrichments showing placer characteristics in the karstic cavities of the carbonate platform. This study, in addition to introducing the general characteristics of this rare karst placer ore formations in the Madenköy area and its surroundings, located in the area where the Central Anatolian Crystalline Complex and the Taurus Belt meet, where the Late Cretaceous- Cenozoic geodynamic evolution is controversial, is also aimed to explain the formation mechanism of these karstic ores in the time-space context of the geodynamic evolution in the region. The petrographic and geochemical characteristics of the quartz porphyry vein rocks containing primary sulphide ore occurrences in the study area indicate an active continental margin environment. They have resemblance to post-collision granites derived from a calc-alkaline magma. Their geochronological ages suggest that the quartz porphyry veins have a genetic relationship with the Eocene age Horoz Granitoid, which is located in the east of the study area. It is thought that from primary sulphide ores there are at least three stages in the development of placer-like secondary oxide ore occurrences located in karstic cavities. The first of these is Early Eocene-Ypresian, the second is Lutetian (Eocene) - Messinian (Miocene); the third one is related to the Zanklian (Pliocene) - Holocene (Quaternary). It is concluded that the karstic structures in the carbonate Bolkardağı platform rocks and the placers within them were formed by hydrogeological and paleoclimatic conditions during the post-Pliocene period following the geodynamic processes affected the region during the first two phases.