Origin of Gypsum Formations in Copper Deposit of Murgul, NE Turkey

The Anayatak and Çakmakkaya orebodies forming the Cu deposit of Murgul in the East Pontic metallotect, NE Turkey were completed before supergene alteration and erosion occurring in short periods of time under subaerial conditions in the area. Furthermore, pyroclastics and sediments (up to 10 m) in the Cu deposit of Murgul represent the short time interval as marker bed. It is an important element for the terrestrial conditions dominated in the area. The local identifier marker bed with ore under atmospheric conditions at the surface, sedimentation dacitic pyroclastics and alteration is interpreted as the result of the erosion events. Gypsum formations located on the upper level of the formerly existing Bognari orebody refer to a brecciated bearing mineralization formed under atmospheric conditions. In this last case gypsum formations can indicate an environment by oxidation of sulfide minerals associated with atmospheric conditions, unlike some of the research results. In Çakmakkaya orebody, gypsum minerals found in altered dacitic pyroclastics are genetically different from above described gypsum minerals. The origin of gypsum minerals can be attributed to seawater sulfates reduced by Fe-oxide/-hydroxide phases. Gypsum minerals in pyroclastics of Anayatak and Çakmakkaya orebodies are not related to host rocks ore mineral assemblage and must be considered as prior to sulfide mineral assemblage. Later on, investigation area exposed to tectonic uplift and subsequent Cu deposit of Murgul formed under terrestrial conditions.