Geochemistry and Genesis of Narigan Ferromanganese Deposit, Bafgh, Yazd Province

The Narigan ferro-manganese deposit is located in 30 km NE of Bafq, and 20 km of Chogart mine. The deposit is situated in Central Iran. Dolomitic limestone and rhyolitic tuffs are the main host rocks.Petrological and ore microscopic data indicate that ore and associated host rocks formed in shallow water, on a platform. Furthermore, geochemical studies show that hydrothermal genesis was responsible for the formation of the ore deposit.Field and petrographical studies show that two stages of hydrothermal activities were involved:1- Exhalation of hydrothermal fluids from seafloor, then primitive ore forming process in the form of precipitation of Fe and Mn oxide and hydroxide gels followed by final crystallization.2- Migration of secondary hydrothermal fluids from reducing to oxidizing area, and transportation and precipitation of Fe and Mn in the latter area; therefore, an increase of ore grade in the oxidizing area.Finally, it could be concluded that at the time of ore formation, rifting had probably occurred in the area, and large volumes of felsic magmas formed. In this way and due to hydrothermal activities, Fe and Mn leached from these rocks and precipitated on the sea floor.