“Kutnohorite”: Mineralogy database and alteration types in the Koushk deposit (Bafq, Central Iran)

The Koushk Zn-Pb shale-hosted massive sulfide deposit is located in the north east of Bafq area within the sequence of lithostratigraphical Rizu unit in the Central Iran (Posht-Badam block). During this study, for the first time in Iran, unknown pink vein minerals are contemporaneous with quartz, located in most of the north and south Pahno stratigraphic units has been introduced as Kutnohorite mineral in the Koushk deposit. Kutnohorite is a type of manganese carbonate with the chemical formula "CaMn2+(CO3)2", belong to the dolomite group. Sampling and geochemical analyses of volcanic-sedimentary host rocks (rhyolite, tuff, shale and dolomite) indicate that high amounts of chlorite, sericite, clinochlore, and euhedral pyrite minerals are found with kutnohorite-quartz veins and associated with galena and sphalerite ores at north Pahno section of the Koushk deposit. According to determining the types of alteration associated with kutnohorite-bearing zone using Ishikawa and chlorite-carbonate-pyrite (CCPI) indices showed that this mineral is an indicator and exploratory key in the Zn-Pb shale-hosted massive sulfide deposits such as the Koushk ore deposit.