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The Dardvey iron deposit, central part of the Sangan mining area, is located in 300 Km southeast of Mashhad and structural zone of eastern Iran. The Dardvey ore deposit is a typical magnetite-rich skarn developed along the contact of Sarnowsar granite with high magnesium carbonate. Skarn zones of Dardvey deposit comprises of exoskarn, endoskarn and ore zones. The exoskarn zone includes, sub-zones of pyroxene skarn, garnet skarn and epidote-phlogopite skarn. According to Electron Micro Prob Analysis (EPMA), the composition of clinopyroxene is diopside-hedenbergite (from Di₄₆–Hd₅₂ to Di₉₆ Hd₃), and composition of garnet is andradite-grossular (from Ad₃₅–Gr₆₃ to Ad₆₀ Gr₃₉). In the skarns zones, there is a compositional variation with increase in Mg and decrease in Fe from the endoskarn to the retrograde skarn. Due to the change of oxidation state towards reduced conditions during paragentic sequences, sulfide saturation was occur. Sulfide saturation produces pyrrhotite, chalcopyrite, and pyrite that simoltaneously and post-dates magnetite and early calc-silicate formation, are other evidences of reducing conditions. Based on content of V, Cr, Ni, Ti, Ca, Al and Mn on magnetite, Darvay magnetite is located in skarn ore deposit. Also, due to existence of endoskarn zone, scapolite and Mg-rich minerals, Darvay skarn is classified as magnesian -calcic skarn.

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Dardvey iron skarn ore deposit is located in the central part of the Sangan mininig area, northeastern Iran. In this study, silicate geothermometr were used to estimate the formation temperatures of skarn zones in Dardvey Fe-skarn deposits. The main metamorphic minerals in prograde and retrograde skarn zones are garnet-clinopyroxene-tremolite/actinolite-amphibole-chlorite-epidote-feldspar-phlogopite-dolomite. Two feldspar geothermometry indicate that endoskarn zone in Sarnowsar granite form at temperatures between 635 to 725 °C, which is not consistent with fluid inclusion tempertures. Based on clinopyroxene-garnet geothermometry, temperature of 300 to 505 ˚C was calculated for prograde skarn stage. Chlorite and Ca-amphibole geothermometry of retrograde zone indicates temperature of 200 to 290 °C and 200 to 300 °C respectively. Silicate minerals geothermometry of prograde and retrograde skarn zones are in accordance with fluid inclusion data. Both geothermometery methodes of prograde and retrograde skarn zones indicate that contact metamorphic sakarn development occuured in <600 ˚C that is consistent with hornblende hornfels facies.

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The Shah-kuh granite batholith (South of Birjand), monozogranite and syenogranite composition, is located on the eastern edge of the Lut block and consists mainly of plagioclase, alkali-feldspar and quartz associated with biotite and tourmaline. The predominant texture of the monozogranite and syenogranite unit is granular to porphyric and granular to micrographic, respectively. Metapelite rocks, host quartz-tourmaline veins, show porphyroblastic texture. Metapelite hosted tourmalines are in the range of dravite and alkaline tourmalines, while granitoid-hosted tourmalines are shorlite type. Presence of properties such as higher Mg content than Fe, low Fe/(Fe + Mg) value, low Al content, tendency towards outside of alkaline depletion and proton depletion vectors and FeO/(FeO + MgO) values less than 0.6 in metapelite host tourmaline veins indicates fluid-rock interaction in an open system far away from the granitoidic body and magmatic-hydrothermal origin. Also, characteristics, such as high Fe/(Fe + Mg) ratio, lack of zoning and proximity to granitoidic body in tourmaline veins with granitoid host rocks, indicates the separation of penomatolitic fluid containing boron (B) from granitic magma and its proximity to B-bearing fluid source. The results of tin analysis in some rock units of Shah-kuh region show that tin mineralization and probably tungsten (more than 500 ppm) are concentrated in quartz-tourmaline veins located in the north and northwest of the study area which is not economic grade (4500 ppm) in the high grade tin deposits.

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The Haft Sandogh alunite deposit is located in the northwest of Takestan (about 60 Km west of Qazvin), and is a part of large Takand alunite deposit. Mineralogical and field study reveal that there is a zonation in the alteration zones of the Haft Sandogh deposit and surrounding area including silica zone in the central part, and quartz-alunite (quartz alunite), kaolinite and propylitic formed toward outer parts. Quartz and alunite are the main minerals of the quartz alunite. Acid-sulfate alteration can be used as a tool in the exploration of epithermal-porphyry ore deposits associated with Cenozoic magmatism in Iran. Regarding to alunite, it can be considered as a potential alternative resource for potassium and alumina production and the decomposition of alunite is a principal step to extract valuable components. Thermal decomposition of alunite was characterized by using differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD) in this research. The DTA curve shows three endothermic peaks at 546 °C, 787.9 °C and 1195.4 °C and an exothermic peak at 737.2 °C. The first peak is associated with the formation of dehydroxylated basic sulphate (KAl₃O₃ (SO₄)₂). The second exothermic peak represents the formation of a new crystalline form of sulphate (KAl(SO₄)₂). The third endothermic peak represents the massive desulphuration by the formation of a basic aluminium and potassium sulphate (KAlO.SO₄). Final endothermic peak represents the formation of Al₂O₃ and leucite (KAlSi₂O₆).
 

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The Chomalu ore deposit is located in the western part of the Alborz magmatic belt (Alborz-Azerbaijan) and geology includes Lower Eocene volcanic to volcanoclastic, including olivine basalt, andesite basalt, andesite to trachyandesite, dacite to rhyolite, and Upper Eocene granitoids including quartz monzonite to quartz monzodiorite. Ore formation in the Chomalu deposit is hosted by olivine basalt and andesite to trachyandesite rocks. The main ore minerals at Chomalu deposit consist of galena, sphalerite, tetrahedrite, pyrite, chalcopyrite, and magnetite. Quartz and fluorite are the main gangue minerals in the Chomalu deposit. Ore mineralization occur as veins and open space filling textures. Field observation shows that mineralization occurred in E-W and NW-SE trending quartz veins. Three mineralization stages were recognized at Chomalu deposit. The geochemical studies show high correlation coefficient indexes between Pb -Zn, Pb-Ag and Cu-Pb and Zn. Vein-veinlets, open space filling and colloform textures; galena, Fe-poor sphalerite, tetrahedrite, pyrite and chalcopyrite mineralization; relatively high base metal sulfides (e.g., Cu, Pb, and Zn); gangue minerals including quartz, fluorite and minor calcite, mineralization with olivine basalt and andesite to trachyandesite as host rocks show that Chomalu mineralization can be classified as IS epithermal deposit.

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The Iranian plateau is located in one of the most complex geodynamic settings within the Alpine-Himalayan belt. The Sangan mining area is the largest Cenozoic skarn iron ore district in the far eastern part of the Alborz magmatic arc in Iran. Granitoid intrusions in the Sangan mining area are subdivided into the fertile Sarnowsar intrusion composed of syenite, syenogranite, and granite; and the barren Sarkhar and Bermani intrusions composed of monzogranite and syenogranite. In this study, we used the zircon geochemical composition from eight samples of Sarnowsar, Sarkhar and Bermani granitoids as an important exploration tool for reconstructing the crustal thickness and its evolution in the Sangan magmatic arc. Zircon Eu/Eu* [chondrite normalized] correlates with whole rock La/Yb, has been used to estimate the crustal thickness. Our results reveal that fertile Sarnowsar granitoids formed in the thicker crust than barren Sarkhar and Bermani granitoids.