Abstract

The paper describes for the first time the Bafq mining district and its deposits of magnetite, apatite, manganese, and base metals. It is based on two decades of field work and the re-evaluation of more than 50,000 m of drill cores.Central Iran is a fragment of Gondwana with a Precambrian basement. Within a Pan-African rift zone a huge Infracambrian volcanic field was formed on top of a silicic diapir, with ignimbritic cauldrons, ring fracture intrusions, and resurgent granites. The volcanic field was partly covered by a shallow sea (shales, dolomitized reefs, salt, and gypsum beds). Along the ring fractures, phreatomagmatic explosions led to the formation of diatremes. They are filled with tuffs, which include basement xenoliths and fragments of rocks which had covered the basement during diatreme formation but which have been eroded together with the upper-most part of the diatreme (eroded xenoliths), welded agglutinates, intrusive breccias, and multiple intrusions of aplosyenite (anorthoclase, scapolite), hornblendite (diopside, magnesio-hornblende), and magnetitite (magnetite, REE-rich fiuorapatite). The magmatic material is considered to be the product of differentiation and liquid immiscibility of a melanephelinitic melt. Magnetitite also occurs as lava flows, sills, dikes, and pyroclastic ores. The explored diatremes of Choghart (mined since 1971), Chador Malu (stripping commenced in 1992), Se Chahun, and Chah Gaz contain 750 Mt of iron ores. Esfordi, a funnel filled with 50 Mt of magnetite-pyroxene-apatite, is being explored. Anomaly XX is a large magnetite prospect associated with uranothorianite mineralization at Duzakh Darreh. Narigan is a manganiferous jaspilite deposit situated in the former moat. Kushk is a subaqueous-hydrothermal massive lead-zinc deposit intercalated in Infracambrian (informal designation in Iran for Upper Riphean-Vendian; 750-570 Ma) volcanics. It is being mined and has 4 Mt of reserves.

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