The study area is located in north of Tehran province. This area is a part of central Alborz zone. Intrusive (basic) and extrusive bodies of late Eocene, have caused several alteration zones. Au- Cu and Pb-Zn mineralization evidences have been found in Darband and Pass-Qaleh areas. The average grade of Pb and Zn in this area is 5% and 3% and the average of Au-Ag is 600 – 10 ppm respectively. Also the amount of 25 and 65 gram per tons has been reported for Au – Ag in this area. Main lithology of this area are volcano-sedimentary rocks of the Eocene. Considering the fact that there is an appropriate stratigraphic situation between lower shale and lithic tuffs for mineralization and due to structural conditions of the area, the conditions of massive sulfide ore forming (KUROKO type) are provided. The major and most important field evidences of this opinion are: The presence of propylitic, serisitic, argillic alterations and their placement; the mineralization type (pyrite, chalcopyrite, galena, sphalerite, jasperoides and Mn-bearing minerals and barite and its sequences and zoning; the existence of thin layers of pyrite in silicified tuffs; Gold mineralization in sulfides minerals; the existence of late hydrothermal phases with increasing of gold ratio and the presence of hydrothermal breccia and silicified veinlet which cut the massive sulfides. In addition, geochemical halos which have extended about 150 meters lead to a polymetalic massive sulfide mineralization that is similar to KUROKO type mineralization.

Abdossamadi barite deposit is located 80 km northeast of the city of Marivan in the northwestern part of the Sanandaj– Sirjan metamorphic zone. The rocks in the deposit area predominantly consist of Cretaceous volcanosedimentary sequences of metamorphosed andesite, calcareous shale and limestone, metamorphosed under greenschist facies grade. The deposit is composed of stratiform ore and stringer zone. The stratiform ore consists of a lens-like barite body associated with sulfide minerals which are underlain by metamorphosed (and altered) andesite (stringer zone) and was under the calcareous shale. Sulfide mineral assemblages of the deposit are simple and consist of pyrite, sphalerite, galena, chalcopyrite, and tetrahedrite-tennantite. Massive, bedded, colloform, framboidal and disseminated structures and textures are common in the stratiform ore and indicate deposition of the deposit on the sea floor. The stringer zone that forming footwall of the stratiform ore is altered andesite that cut by sulfide-bearing quartz-barite veins and veinlets. Fluid inclusion studies indicated that barite samples in the stratiform ore homogenized between 115° and 215° C. Salinities of the fluid inclusions show a range from 0. 21 to 5. 86 wt. % NaCl equivalent. Cooling of the ore-bearing hydrothermal fluid is an important process in the stratiform ore deposition. This study shows that the barite deposit is an immature KUROKO type massive sulfide deposit, which contains only black ore. The deposit underwent metamorphism and deformation after the ore deposition and therefore, shows significant changes in ore structures and textures.

The study area (Pasghaleh) is located North of Tehran and is part of the Central Alborz Mountain Range. Pasghaleh deposit between coordinates 51º 25´ 15 ̎ up to 51º 25´ 54̎ Eastern longitude and 35º 49´ 42 ̎ up to 35º 50´ 15 ̎ Northern latitude in North of Tehran, in the geological sheet with a scale of 1: 100000 Tehran and is located East of the Pasghaleh village. Intrusive bodies in this area with age after the Eocene in penetrating Eocene volcanic and pyroclastic units and have altered these units. For mapping minerals and explore the alteration patterns together with Polymetal mineralization in the metallogenic zone Pasghaleh, for sine satellite ASTER and ETM spectral processing and interpretation. According to remote sensing data, it leads to the appearance of Kaolinite and Montmorillonite minerals (Argillic alteration index), Chlorite, Epidote and Calcite (Propylitic alteration index), Muscovite (Sericite alteration index) and Gossan in the range studied. Major mineralization in the region in acid Tuffs altered and scattered. The lithology of this region including pyroclastic rocks of Karaj Formation with Eocene age. Sulfuric minerals observed Pyrite, Chalcopyrite, Sphalerite and Galena. In the whole region Pyrite expands but Lead mineralization, Zinc, Copper, Gold and Silver which process is parallel to the general layering of classes Tuff Silica altered-Feldspathic-Pyrite slightly observed. Pyrite form syngenetic among the Tuffs. Tuffs in formation stage and in the stage of diagenesis, the alteration process Sericitic, Kaolinite and or Chlorite have tolerated. In terms of construction, altered zone mineralize Pasghaleh as a lens and layers plate form between rock units Dacite, Rhyodacite are formed. Based on the study of remote sensing data, presence of alterations Sericite, Argillic and Propylitic (the presence of Chlorite and Epidote) proven in the region, consequently by putting together these alterations to one another, it can be attributed to the alteration pattern of KUROKO Massive sulfide deposits.

Barika deposit is the first and only recognized gold (and silver) rich-massive sulfide deposit in Iran which is located at 18 km east of Sardasht city, north western part of Sanandaj-Sirjan metamorphic zone. Rock units outcropped in this area are volcano sedimentary metamorphosed rocks in green schist facies, and include association of metaandesite, metatuffite, phyllite and slate rocks, among which the metaandesitic unit (KMv1) is host rock of the deposit. Ore mineral assemblages in stratiform part of the deposit, which contain massive and banded pyrite and barite associated with subordinary silica bands, are very variable in composition and consist of pyrite, sphalerite, galena, stibnite and a variety of sulfosalt minerals and electrum. Ore mineral assemblage in silicic veins in stringer zone, are simpler and consist of pyrite, galena, sphalerite, tetrahedrite and rare chalcopyrite. Average gold and silver grades in stratiform ore are 4.2 and 260 g/t respectively and in silica stringer veins are 0.7 and 30 g/t. Base metal content in both part of the deposit is less than 1%. Lithotectonic study and trace and rare earth elements diagrams associated with Ce/Pb and Nb/U ratios of the metavolcanic rocks in the deposit area indicate that the rocks were generated from a lithospheric mantle source in the active continental margin of the SSZ. A geochemical study of Barika deposit reveals that distribution patterns and correlation coefficient of ore elements in parts of the Barika stratiform ore and stringer zone are completely in correlation with an undeformed massive sulfide deposit. The geochemical documents indicate that despite the metamorphism and highly deformation on the deposit, the primary distribution patterns and proportion of the ore elements are well conserved, as geochemical characteristics of the Barika deformed deposit is as well as correlated with an undeformed gold- rich volcanogenic massive sulfide deposit. However there is clear textural evidence for remobilization of As, Sb, Ag and Pb minerals together with Au in Barika deposit, but, remobilized constituents of the ores do not appear to have moved beyond the margins of the ore bodies and primary metal zonation.

The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering of the host rocks. Ore structures and textures are dominated by semi-massive to brecciated, banded and vein-veinlets. Main primary minerals are galena, pyrite and chalcopyrite, and secondary minerals are dominated by covelline, goethite and hematite. Gangue minerals are epidote, chlorite, sericite, clay minerals, quartz, calcite and barite. Wall rock alterations are dominated by epidote-chlorite and sericitic. The rare earth element (REE) pattern of ores is not similar to that of volcanic rocks in the footwall and hangingwall that is concordant with sub-seafloor replacement process for ore formation. Also Ce showed negative anomaly that can be attributed to Ce in the seawater. Also based on structural, stratigraphic, petrographic, textures, mineralogical, alteration and geochemical studies, it is inferred that the Pb (Ag) mineralization in the Darreh Amrood area occurred as bimodal felsic-or KUROKO-type volcanogenic massive sulfide (VMS) mineralization, and formed as sub-seafloor replacement. It should be noted that the Darreh Amrood deposit is the first recognition of base metal-rich and poor barite VMS mineralization in the UDMA.

Bijegan Tappeh-Sorkh-e Barite Mine located at 21 Km southeast of Delijan and 4 Km from northwest of Bijegan Village in Markazi Province, and belongs to volcanic belt of Oroumieh-Dokhtar, is one of the most active volcanic belt. The nature of the host rock is igneous and its age is late Eocene-Early Oligocene? Ore body is nearly lenticular shape adjacent to Certaceous marl, along the fault, with dimensions of 50*15*6 meter and NE-SW trending. It is located between Eocene Volcanic and Lower Red Formation (LRF). Red color of the ore mineral is related to the Fe-hydroxide resulted from high level of fugacity of the environment.The morphology of mine area consists of three parts, Stockwerk of stringers, Massive Barite ore and Hematite red chert. The massive ore body including Barite, Hematite, Quartz, Malachite and Azurite.As a result of high level of barite compared with sulphide ores and wide extent of massive section compared with stockwerk and its simple structural region sorting, mine of Tappeh-Sorkh can be conformed to specifications of KUROKO type of barite mine.

Barika gold (and silver)-rich volcanogenic massive sulfide deposit is located 18 km east of Sardasht in the northwestern Sanandaj– Sirjan metamorphic zone. The rocks in the vicinity of the Barika deposit predominantly consist of Cretaceous volcano-sedimentary sequences of phyllite, slate, andesite and tuffite, metamorphosed under greenschist facies grade. The Barika deposit is composed of stratiform ore and stringer zone which both are hosted in an altered and sheared meta-andesite unit. The stratiform ore, approximately 150 m long and up to 20 m thick consists of sulfide and barite ores associated with lesser amounts of silica bands. Fluid inclusion studies indicate that quartz (stringer zone) and barite (stratiform ore) samples homogenized between 146° C to 283° C and 132° to 223° C, respectively. Salinities of the fluid inclusions show a range from 1. 4 to 9. 6 wt. % NaCl equivalent which are close to that of normal seawater. The study indicates that cooling occurred in the initial ore fluids, as a result of mixing with seawater, as an important process in the formation of the Barika deposit. The δ 34S values of sulfide minerals (pyrite, sphalerite and galena) from stockwork mineralization in the Barika deposit range from-0. 8 to +5. 6 per mil and fall within the range of values observed for volcanogenic massive sulfide deposits. The narrow range of measured δ 34S values from the sulfide minerals suggests that similar to most KUROKO VMS deposits, the ore-forming sulfur derived from leaching of igneous sulfur from the underlying andesitic rocks. Calculated sulfur isotope temperatures for twelve coexisting galena-sphalerite and galena-pyrite pairs range from 146 to 293° C which is consistent with temperatures estimated from fluid inclusion studies.

Shekarbeig barite deposit is located 46 km southwest of Mahabad in northwestern part of the Sanandaj-Sirjan zone. The outcropped rock units in the area are Late Protrozoic metamorphosed volcano-sedimentary rocks, equivalent to Kahar Formation. The main ore mineral occurs as stratiform barite lenses in three horizons accompanied by sulfide minerals as massive and/or parallel bands within metamorphosed rhyolitic tuffs (metatuff). The deposit footwall is composed of phyllite and slate crosscut by silicic and sulfide-bearing barite veins and veinlets (stringer zone). Primary minerals in the ore are mainly barite, pyrite, marcasite, chalcopyrite and bornite and secondary minerals are chalcocite, covellite, malachite, siderite, goethite, hematite and other iron hydroxides. Gangue minerals include quartz, sericite, calcite, dolomite, feldspar and chlorite. In terms of metallic ores, the Shekarbeig deposit does not vary much having only pyrite and chalcopyrite. Types of fluid inclusions in the Shekarbeig deposit are two-phase liquid-vapour (LV), mono-phase vapour and mono-phase liquid, two-phase liquid-vapour being the dominant type in both stringer and stratiform parts. Sulfur isotope data indicate that seawater was the main mineralizing fluid for Shekarbeig mineralization. These data suggest that complete reduction of recent seawater sulfate and the rate of mixing of hydrothermal solution with cold waters in deep parts of the basin may result in precipitation of large amount of sulfides in the stringer and stratifrom zones. On the other hand, partial reduction of recent seawater sulfates provided required sulfur for the deposition of barite. Geological evidence, evaluation, lithostratigraphy, mineralization geometry and the results of fluid inclusion and sulfur isotope studies for samples from the Shekarbeig deposit indicate derivation of the hydrothermal fluids of low salinity and moderate temperature from seawater and circulation and upward movement by a heating source (probably subvolcanic intrusions) and finally cooling and deposition of the fluids as sulfate and sulfide on the sea floor due to mixing with seawater, similar to massive sulfide KUROKO-type deposits.

Barika gold mineralization occurred in a Cretaceous metavolcano-sedimentary sequence at northwestern Sanandaj-Sirjan zone. Major units in this area include Cretaceous Submarine volcano-sedimentary rocks. Host rock of mineralization is rhyolite to rhyolitic tuff unit which is completely in Barika shear zone. Mineralization occurred as lenticular ore bodies that has developed parallel to Barika shear zone foliation. Mineralization from footwall to hanging wall consists of: 1- Silica-Sulfide zone, which includes two part, pyrite-rich part and quartz with sulfide veins that crossed with shear zone foliation. Gold grade in pyrite-rich part is between 0.02 to 5 ppm and in quartz sulfide-bearing veins is between 0.05 to 0.5 ppm. 2- Sulfide and sulfosalt-rich zone. This zone contains of two part, pyrite-sphalerite-sulfosalt and massive pyrite part. Gold grade in this zone is 0.02 to more than 100 ppm. 3- Massive barite ore zone. This zone included of some barite lenses that longer lens has 10 thickness and about 60 m length. This zone is contained two parts, a sulfide and sulfosalt-rich part and sulfide and sulfosalt-poor part. Gold grade in sulfide and sulfosalt-rich part is between 0.02 to 25 ppm. Major minerals in mineralization zones are pyrite, sphalerite, galena, tetrahedrite-tenantite, bournonite-boulangerite, twinnite-veenite, stibnite, electrom, chalcopyrite and covelite. Electron microprobe studies on different minerals showed that gold occurs as electrom, and in minerals compose such as pyrite, galena and sulfosalts. The most important characteristics of mineralization of the Barika gold mineralization such as tectonic setting, host rocks, mineralogy, metal contents and metal zonation, wall rock alterations, shows similarities with gold-rich volcanogenic massive sulfide (VMS) deposits, e.g. , Rosbery, Hellyer and Que River deposits in Tasmania and some KUROKO type deposits at HoKUROKO Basin, Japan.