Economic Geology
SHAHRAM RAHMANI; Hasan Zamanian; reza Zarei Sahamieh
Abstract
Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran ...
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Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran type. The intrusive rocks are enriched in LILE, LREE and depleted from HFSE, MREE and HREE and Y. A listric-shaped REE pattern and average La/Yb ratios of host rock indicates higher water content and fO2 in the magma and hornblende fractionation. Their relatively low to moderate ISr values (0.7047–0.7051), positive εNd (t = 36 Ma) values (0.39–2.1) and TDM ages of 0.69 to 1.06 Ga, with Pb isotopic ratios of (206Pb/204Pb) i = 18.49–18.68, (207Pb/204Pb) i = 15.58–15.61 and (208Pb/204Pb) i = 38.33–38.77. Based on textural evidence (coarse amphibole crystals), geochemical data (major, trace and Rare earth elements) and isotopic contents of Pb, Sr-Nd, it is suggested that these rocks correspond to geochemical and isotopic compositions of the host rocks of porphyry and epithermal deposits in the Urmia Dokhtar zone of West Alborz-Azerbaijan (Arasbaran) and Eastern Pontides epithermal deposits, Turkey.
Hasan Zamanian; Ghasem Beiranvand; Farhad Ahmadnejad
Abstract
Bagoushi deposit is located in 37 km northwestern Masiri in Fars province. Structurally the deposit is situated in the Zagros Simply Folded Mountain belt and developed in Upper Cretaceous carbonates. From the top to bottom, the deposit is consisting of red, pisolitic, brown, brecciate, and kaolinitic ...
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Bagoushi deposit is located in 37 km northwestern Masiri in Fars province. Structurally the deposit is situated in the Zagros Simply Folded Mountain belt and developed in Upper Cretaceous carbonates. From the top to bottom, the deposit is consisting of red, pisolitic, brown, brecciate, and kaolinitic bauxite horizons. Boehmite, kaolinite, hematite, pyrophyllite, anatase, calcite and diaspore are the major mineral phases. The main ore textures of the deposit include pisolitic, pisolitic-oolitic and clastic with pelitomorphic and microgranular matrixes. According to the formation conditions of the major minerals, the Bagoushi deposit formed in an environment ranging from acidic-oxidizing surface water to basic and reducing groundwater. Some textural features such as pelitomorphic matrix, pisolitic and oolitic textures, radial fractures in pisoids, growth of simple cortex around earlier pisoids, pisoids with cortexes lacking radial and circular fractures, are indicative of allochthonous origin; and broken pisoids, allogeneic pisoids and clastic grains reveal the transportation of bauxitic materials; therefore the bauxite materials is authigenic, but in some parts were transported and re-deposited, at least locally. The mass change calculations relative to the immobile element Ti show that elements such as Si, Fe, Mg, K and Na are leached out; Al, Zr, V, Th, Nb, Ba and REEs particularly LREE are concentrated; and Hf, Ta, Co, Rb, Cs, Be and U are relatively immobile during the bauxitisation process. The bauxite ores are characterized by progressive enrichment of the REE compared to parent rock, intense LREE/HREE fractionation, relatively stable negative Eu anomalies, and weak negative Ce anomalies.
M. Amiri; A. Ahmadi Khalaji; Z. Tahmasbi; R. Zarei Sahamieh; H. Zamanian
Abstract
The intrusive bodies of Almogholagh Batholith, in western Iran are emplaced into the Sanandaj–Sirjan magmatic-metamorphic zone and comprise three main groups: (1) gabbro-diorite, (2) quartz syenite, and (3) quartz monzonite, which crop out in most of the area. The quartz syenite and quartz monzonite ...
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The intrusive bodies of Almogholagh Batholith, in western Iran are emplaced into the Sanandaj–Sirjan magmatic-metamorphic zone and comprise three main groups: (1) gabbro-diorite, (2) quartz syenite, and (3) quartz monzonite, which crop out in most of the area. The quartz syenite and quartz monzonite rocks, having characteristics such as metaluminous, generally ferroan, alkalic to alkali-calcic types, high content of Na2O+K2O, Zr, Ce, Ga, Y, Nb, Ta, REE, and depletion in Eu, Sr and Ti, show the features of borderline between A1 and A2-type granitoids with more A1-type affinity. On the basis of the results of the various diagrams, the gabbroic-dioritic rocks show between A1 and I-type granitoids nature with more I-type affinity. Distinctive peak patterns in spider diagrams accompanied by (La/Yb)CN values of 2.4 to 6.1 and Ba/La ratio >3 indicate magmatic activity in a volcanic arc environment, and the characteristics (Ba/Rb)CN<1, (Ba/Th)CN 143Nd/144Nd > 0.512638, εtNd >0, εtSr >0, high content of Nb, Ta and very high content of Zr (589 ppm) indicate that there was a subsidiary subduction after the initial collision for a long time and the magmas of Amogholagh batholiths were originated from mantle wedge, overlying the subduction zone or from mantle components around fragments resulting from delamination between continental crust and mantle lithosphere, demonstrating the involvement of subduction zone fluids, high flux of mantle-derived halogen-rich volatiles, and contamination within the crust during the petrogenesis of intrusions.
A. Zarasvandi; H. Zamanian; E. Hejazi; A.H. Mansour
Abstract
The Sar-Faryab bauxite deposit is located in 250 km east of Ahvaz city in Kohgeloye and Bovair-Ahmad Province, Iran. Structurally the deposit is located in the Zagros Simply Fold Mountain Belt and was formed between the Ilam and Sarvak Formations. The bauxite horizon in this deposit consists of ...
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The Sar-Faryab bauxite deposit is located in 250 km east of Ahvaz city in Kohgeloye and Bovair-Ahmad Province, Iran. Structurally the deposit is located in the Zagros Simply Fold Mountain Belt and was formed between the Ilam and Sarvak Formations. The bauxite horizon in this deposit consists of marly limestone, argillite, oolitic-Pisolitic, yellow, red and white bauxite. This study uses the geochemistry of immobile elements (Al, Ti, Zr and Y) to trace the precursor rock of the bauxite deposit and to calculate the mass changes that took place during weathering and bauxitization. The result indicates that elements are depleted and elements are enriched during the weathering and bauxitization. Geochemical data show that argillaceous debris in the Sarvak limestone can be the source of the Sar-Faryab bauxite deposit.
