Formation of calamine in Ahmadabad Zn (Pb) Non-sulfide deposit (Northeast of Bafq)

Ahmadabad calamine deposit is located in Posht-e Badam block, 80 km of northeast of Bafgh. The dolomitic unit of Shotori Formation is Middle Triassic age and is ore deposit host rock. Primary non-sulfide mineralization belongs to the Upper Triassic to Jurassic and includes galena, sphalerite and pyrite since being affected by subsequent tectonic phases- are crushed, uplifted, weathered and oxidized and produced non-sulfide minerals. Calamine, Cerussite, wulfenite, iron oxide and hydroxide are the most abundant non-sulfide minerals in the region. Mineralogical and field observations revealed that calamine is formed in two ways, i.e. direct replacement and wall- rock replacement. Direct replacement calamine is formed at the site of primary sulfide mineralization and has more mineralogical variability compared with the wall-rock replacement type. Mineralogical characteristics of the minerals revealed, metal-rich solutions perform non-sulfur mineralization in the unsaturated zone, within the porous host rock and the type of mineral is affected by changes in carbon dioxide pressure and ambient pH. The average values of the oxygen stable isotope data of hydrozincite is 25.5‰; therefore, the average temperature for the formation of this mineral is 29 ºC. Chemical analysis showed that the direct replacement calamine has more lead and the other type has more zinc, and due to the high concentration of arsenic and cadmium in the mineral composition of the area, more attention should be paid to the environmental issues.