Rare Earth Minerals in Esfordi Magnetite-Apatiteore Deposit, Bafq District

The Esfordi magnetite-apatite ore deposit is located in 35 Km northeast of Bafq city in Central Iran. Bafq is an important mining district which hosts more than 45 iron deposits and a few Zn-Pb massive sulfides, Mn and U deposits. The district is restricted by two main strike-slip faults of Kuhbanan to the east and Posht e Bdam to the west. The Esfordi ores occur in an Upper Precambrian-Cambrian volcano-sedimentary complex composed of acidic tuff, carbonates, shale, and sandstone. This complex intruded by granitic rocks and basic dykes and affected by regional and contact metamorphism and hydrothermal alteration. The Esfordi magnetite-apatite ores occur on top of the acidic tuff which is near to a carbonate layer. The Esfordi deposit is the most rare-earth elements (REE)-rich and most P-rich member of the iron deposits in the Bafq district. The main minerals in the Esfordi mine are Iron oxides, apatite, actinolite, diopside, talc, andradite, feldspars, quartz and carbonates. The REE minerals are closely related to apatite and were mainly formed in or around apatite grains and within veins and veinlets. This paper identifies the REE minerals and presents preliminary information on mineral composition and geological and mineralogical features of the deposit. The REE-bearing minerals are mainly of phosphate, fluorocarbonate and silicate groups. The REE minerals are highly enriched in light REE such as Ce, La, Nd and Pr. Apatite contains a few percent REE in its composition. However, the main part of REE may be from apatite as it is the main mineral of the deposit and apatite-rich horizons contain high-grade REE ore. The metasomatic assemblage, one head crystals of apatite and many mineralized veins and veinlets indicate that hydrothermal process were definitely active in the Esfordi deposit at later stages.