Structural, textural, mineralogical and geochemical features and the pattern of the Angoran ore deposit in the Sedex-VMS-MVT triangle

The Angouran Zn-Pb deposit is located about 120 Km Zanjan Province, within Sanandaj-Sirjan Zone.The deposit occurs in metamorphosed schists and marbles of Proterozoic age. The deposit contains about 4.7 Mt of sulfide ore, grading 27.7% Zn, 2.4% Pb and 110 g/t Ag and 14.6 Mt of oxidized carbonate ores, grading 22% Zn and 4.6% Pb. The Angouran Sedex deposit formed as a result of continental rifting and exhalation of seawater hydrothermal solutions into the seafloor and syngenetic deposition of sphalerite and galen within shales and carbonates. The deposit was then metamorphosed along with schists and marbles. Supergene oxidation of sulfide minerals and redeposition and replacement of zinc and lead formed the non-sulfide carbonate ores in Quaternary period. Based on structural, textural, mineralogical and geochemical evidence such as sulfides-schists foliation in marbles and schists, elongation of pyrite and sphalerite, high grade of Zn (28%), low grade of Cu (0.014%), and the absence of space filling and vein controlled mineralization, the Angouran Zn-Pb deposit resembles the exhalative sedimentary (Sedex) deposit, rather than Mississippi valley type (MVT) or volcanogenic massive sulfide (VMS) deposit.