Abstarct: The Vanakan (Sokan) barite-zinc-lead-copper deposit is located in 23 km northeast of Semnan, in the North Central Iran magmatic belt, and occurred within the Eocene volcanic-sedimentary sequence. The host sequence in the Vanakan deposit involves three rock units, from bottom to top: Unit1: conglomerate, limestone, sandstone; Unit2: andesitic to dacitic lava-rich, and unit3: acidic tuff-rich. Mineralization occurred as Vanakan 1 and 2 deposits at top of the unit 2 and within the unit 3. The entire of the Vanakan area involves a local syncline with northeast-southwest axial trend, in which the vanakan 1 and Vanakan 2 deposits located in the northern and southern limbs of the syncline, respectively. Ore host rocks are tuff, shaly tuff, and andesitic and trachyandesitic lava. Mineralization in the Vankan deposit occurred as three ore horizons, which include: first horizon (OH-1): involving the Vankan 1 and 2 deposits hosted by tuff, shaly tuff and andesite, the second horizon (OH-2): observed in the northwest of the area hosted by siliceous tuff, and third horizon (OH-3): located at near the axis of the syncline within tuff. baxsed on structural, textural and mineralogical studies, five different ore facieses were distinguished in Vanakan 1, from bottom to: 1) vein-veinlet and breccia: involving barite-pyrite-quartz vein-veinlets, 2) massive sulfide: composed of massive sphalerite, galena, barite, chalcopyrite and pyrite, 3) laxyered-banded sulfide ore: involving alternations of ore and sericite altered tuff-rich bands, 4) baritic ore: comprising of mainly barite and little sulfides, and 5) banded-exhalative cherty sediments. The ore facieses in the Vanakan 2 from bottom to top are 1) barite - (galena)-rich vein-veinlets and 2) banded cherty iron oxide-hydroxides -rich red exhalative sediment. Mineralogicaly, the ores in the Vanakn 1 consist mainly barite, sphalerite, galena, pyrite, chalcopyrite and marcasite accompanied with secondary minerals such as malachite, chrysocolla, smithsonite, cerussite, hematite, limonite, goethite. The major wallrock alterations of the Vankan deposit are chloritic and sericitic, and minor argillic, silicic, carbonatic and epidotic. Geochemical studies on the ore-bearing facies of Vankan 1 indicate lead (up to 33865 ppm) and copper (up to 9808 ppm) enrichment in the massive sulfide ore. Zinc and silver were enriched in the in the laxyered-banded sulfide ore up to 213390 and 233 ppm, respectively. The associated lava and intrusions show clalc alkaline nature, formed in a volcanic arc basin. According to microthermometery study, fluid inclusions are dominated by two phase liquid-vapor (L+¬V) with an average salinity of 12.64 (3.65-21.49) wt% equivalent to NaCl, and an average homogenization temperature of 160 (110-195) °C. According to these studies and basic ore mineralization characteristics, the Vanakan deposit could be classified as a bimodal- felsic or Kuroko-type volcanogenic massive sulfide (VMS) deposit.