Iranian Journal of Crystallography and Mineralogy
Year:2018 | Volume:26 | Issue:3|Papers Count:20

The Kangareh gabbro body is located in south of the Kurdistan Povince and southwest of the Qorveh area. The area belongs to the Sanandaj-Sirjan zone. Tectonic evolutions during Mezozoic and magmatism, due to subduction of the Neo-Tethys oceanic lithosphere beneath the Iran microplate, led to formation of various igneous bodies in this area. Chemical analysis of pyroxene minerals and whole rock analysis show that the Kangareh body has metaluminous nature and belongs to tholeiite to calc-alkaline magma series. The studied samples have geochemical properties of subduction related igneous rocks such as negative Nb, P, Ti and Zr anomalies and positive Rb, Sr and Eu anomalies. The results of this study also indicate that the Kangareh gabbro body formed in an island-arc tectonic setting. On this basis, it can be concluded that there were island-arcs in adjacent to the Iran continental margin (Sanandaj-Sirjan zone) during Mesozoic that were attached to the Iran continental margin (the Qorveh area) after closure of Neo-Tethys ocean.

Namegh area is located northeast Kashmar, Khorasan Razavi Province, and contral parts of the Khaf-Kashmar-Bardaskan magmatic belt. Geology of the area consists of trachyandesite and pyroclastic rocks including trachyandesitic to rhyolitic tuff, which are intruded by monzodioritic dykes. Mineralization is occurred as vein type with NW-SE trending and 75° NE inclination hosted by trachyandesite and trachyandesitic tuff. Primary minerals are specularite, chalcopyrite, and magnetite and secondary minerals are goethite, hematite, and malachite. Silicification is the most important alteration. High anomaly of Cu (up to 2%) and low values of Au (maximum 20 ppb) are present in the vein. Based on fluid inclusion studies, formation temperature of mineralization is between 300 to 496 º C and it is occurred from NaCland CaCl2-bearing fluid with 11 to 22 wt. % NaCl equivalent salinity. Temperature and salinity is decreased and dilution occurs due to mixing of two high temperature-salinity and low temperature-salinity fluids resulting Fe oxide and copper is deposited from chloride ligands. Mixing of magmatic and meteoric waters model is the best model for generation of Namegh iron-copper vein. This mineralization is occurred at 10 to 60 Mpa pressure and 0. 5 to 2 Km depth (assuming lithostatic pressure). Mineral paragenesis, host rock, alteration, structural control, and nature of ore fluid indicate mineralization is Iron oxide-copper hydrothermal type.

The Gol-Gohar metamorphic complex is located about 55 km southwest of the Sirjan and is part of east Sanandaj-Sirjan zone. The rocks units are metamorphosed in greenschist and upper amphibolite facies with age of Middle Jurassic which consists of metapelitic (mica-schists and gneisses), metabasitic and metacarbonatic rocks. Geochemical studies indicate that the precursor sediments of the metapelites had been deposited as immature shales and grywackes from source materials of dominantly felsic to intermediate composition. Source area exhibited weak to moderate chemical weathering. The relatively low contents of Cr (average 99. 67 ppm) and Ni (average 56 ppm) in the studied schists are comparable with the concentration of these elements in post-Archean schists. Study of gneisses in the Gol-Gohar area indicates that these rocks are sedimentary in composition (para gneiss) and were derived from rocks with weakly peraluminous.

In the eastern part of the Sabzevar ophiolite, southeast of Soleymanieh, there are white to pale greenish veins of diopsidite with 1– 15 cm width inside mantle serpentinized harzburgites. The center of these veins is rather homogeneous and includes a monomineralic clinopyroxen with granular texture. The contact between the pure clinopyroxene and its host peridotite is always progressive and characterised by replacement textures and minerals. The host harzburgite has also been affected by diopsidization. There are patches of cores grain altered plagioclase and clinopyroxen with inclusions of serpentine in the host harzburgite. The mineral assemblage, field relationships and mineral chemistry of the mantle diopsidites in the eastern part of the Sabzevar ophiolite indicate that they are product of circulation of very high temperature hydrothermal fluids (550– 900 ° C) rich in Si, Ca, Mg, CO4 2– , SO4 2– and Cl– in the upper mantle. These fluids leached plagioclase rich lithologies before penetrating the mantle.

Northeast Kamyaran ophiolitic complex is mainly composed of harzburgite along with small outcrops of lherzolite. Harzburgites are extensively altered to serpentinite. Small lenses of chromite mineralization are observed in harzburgites. The mineral assemblage present in the study harzburgite and lherzolite are olivine, orthopyroxene and clinopyroxene along with minor amount of spinel. Microprobe studies on the spinel indicate that it is Cr and Al bearing spinel (Cr-spinel) with very high Mg# (55. 2-71. 9) and Cr# (34. 3-45. 5) values and low values of TiO2 (with average value of 0. 6 wt%). Fe3+ content of the Cr-spinel in the study rocks is high (with average value of 0. 8 wt %) indicating that the crystallization occurred at high oxygen fugacity. According to the microprobe data, MgO content of olivine varies between 50. 04 and 52. 99 wt% and its composition is forsterite (Fo90. 68-91. 42). Based on the mineral chemistry of spinel, peridotites of Northeast Kamyaran ophiolitic complex belong to residual depleted peridotites which have formed in mid ocean ridge tectonic setting.

The north western part of volcano-sedimentary complex of Davazdah-Emam mountain in north of Central Iran is located about 135 km SE Tehran. The Eocene to Oligocene volcanic rocks and dikes of intermediate to mainly basic of complex under the influence of hydrothermal fluids, probably associated with the involvement of meteoric water, experienced different degrees of alteration. The alteration occurred in two steps forming mafic phyllosilicates (celadonite, mixed layers of celadonite-nontronite, smectite), calcite and sodic zeolites (analcime, tetranatrolite, natrolite and chabazite-Ca) at the first step and in the second step, hydrothermal associated possibly with the involvement of the meteoric water facilitated the disposition of calcic-sodic zeolites such as stilbite-Ca, mesolite and thomsonite. Variatians in temperatures, pH, CO2 and H2O values, Si/Al ratio and host rocks types are the parameters that causes the diversities of mineralization through out the two steps. Maximum and minimum temperatures of zeolite formation for the first stage can be estimated around 145° C for analcime and 90° C for chabazite-Ca and for second stage, around 75° C for stilbite-Ca and 65° C for thomsonite.

The Kuh Zar Au-Cu deposit is located about 100 km southeast of Damaghan city. Structurally, this area is part of the Alborz Magmatic Assemblage (AMA). The oldest rock units in the Firuzeh-Gheychi area consists of syenogranite and tourmaline biotite granodiorite units. These units were intruded by quartz monzonite porphyry stocks. Pyroxene diorite porphyry and hornblende diorite porphyry are younger than all of the rock units mentioned. They were intruded by syenogranitic and monzogranitic dikes. All units have been affected by QSP, propylitic, argillic and silicification-tourmalinization alteration zones. Mineralogy studies show that the seven main groups of veinlets in the area included I: quartz-pyrite-chalcopyritetourmaline, II: quartz-chlorite-pyrite-tourmaline, III: quartz-pyrite, IV: quartz-pyritechalcopyrite, V: quartz-tourmaline-pyrite, VI: tourmaline-pyrite and VII: pyrite-chalcopyritechlorite-tourmaline. Fluid inclusion petrography also shows that dominant primary fluid inclusions of the two-phase LV and single-phase L are the rich liquid. Microthermometric studies show that the homogenization temperature and salinity range for type-I veinlet fluid inclusions are 428 to 486

Natanz, 1: 100000 geological map, is located in northeast Isfahan, in the Urumieh-Dokhtar structural zone. This sheet is a prospective area for Cu, Zn and Pb mineralization. Spatial distribution of geochemical anomalies for mineralization was identified; using pathfinder elements statistic method. The sample from catchment basin technique was applied on stream data. Then threshold elements were recognized and separated anomalies. The results show a good distribution of Pb, Zn, As and Sb elements close to copper index in the Natanz map. Moreover, fractal model used to introduce new anomalies in south portion of map for future exploration prospecting.

Isotropic gabbros of Kermanshah ophiolite include olivine gabbro, gabbro, gabbronorite, olivine gabbronorite and troctolite. The isotropic gabbros are medium to fine grained with euhedral to subhedral orthopyroxenes, clinopyroxenes and subhedral plagioclase, olivine together with rare amphiboles. Mineral chemistry of isotropic gabbros reveal that the clinopyroxenes are diopsidic to augitic in composition within the compositional ranges of En(50. 91– 45. 79), Fs(7. 41– 3. 64), and Wo(48. 5– 43. 81). They are Ca-rich and Na poor (Na2O < 0. 54 wt%) characterized by high-Mg (Mg# 85. 62– 89. 35) and low-Ti (TiO2 < 0. 28 wt%) contents. Plagioclases are bytownite in compositions (An(70. 51– 90. 15), Ab(9. 62-29. 02) and Or (0/00-0. 63), orthopyroxene are mostly enstatites within the compositional ranges of En(78. 27-84. 94), Fs(13. 0-20. 07) and Wo(1. 43-3. 36), olivine, forstrite and amphiboles are Mg-rich (tremolite, actinolite to actinohornblendes) with Mg# (64. 35-84/86). The presence of highly magnesian olivines (Fo 80. 07– 84. 82), clinopyroxenes (Mg# 85. 62– 89. 35), and orthopyroxenes (Mg# 79. 59– 85. 72) as well as highly calcic plagioclases (An 70. 51– 90. 15) and amphiboles in the isotropic gabbros indicates a subduction-related tectonic environment. The tectonic discrimination plots of clinopyroxene data indicate island arc signature of the source magma. The results of studies confirm that the Kermanshah ophiolite formed in a suprasubduction zone environment in the southern branch of Neotethys.

The Hormuz Formation is a sequence of lithologically various evaporitic– volcanic rocks in salt domes where the volcanic rocks are dominantly acidic, generally with less than one third basic volcanics. It was formed in the Late Proterozoic (640– 620 Ma)/Neoproterozoic– Early Cambrian, as a result of sub-basin rifting in the northern part of the Arabian plate, throughout most of the Persian Gulf Basin and the equivalent Ara salt in Oman. Diabase is the most common basic rock of the Hormuz Formation. In the field, the studied diabases are seen as stock-like outcrops and dykes which are extremely altered. These rocks contain plagioclase, pyroxene and less olivine as primary minerals which are transformed to various secondary minerals and the diabases primary textures are ophitic, porphyritic and microlitic flow. 22 samples of these diabases from 7 salt domes of southern Iran were analyzed by XRF and ICPMS methods and then studied. On geochemical diagrams, these rocks plot in the field of tholeiitic basalts and mid-oceanic ridge basalts (MORB). According to values of major and rare elements, these diabases have undergone fractional crystallization within a magma chamber or en route to the surface. Due to REE pattern and values of these samples, the parental rock of the magma which produced them has experienced intermediate degrees of partial melting and these diabases have undergone low degrees of crustal contamination during magmatic evolution. According to values of rare elements ratios, they were probably generated from a depleted to transitional mantle source derived from a garnet-free, spinel peridotite source region. Therefore, the Hormuz Formation diabases are products of the Neoproterozoic to Early Cambrian rifting of the northern part of the Arabian plate. They have similar chemical compositions as Archean tholeiitic basalts and show all the features of a greenstone but whether or not they are on a Phanerozoic greenstone belt, needs further tectonic studies.

Infrared spectroscopy in the middle wave range (MW-IR: 4000-200 cm-1) is a powerful tool to decipher the molecular groups in the minerals and thus to identify the chemical composition of the mineral phases. The purpose of this work is to determine the chemical composition of illite in the fraction 2-6. 3 0m (fine silt) of the sample from the Stoob (East-Austria). The The illite chemistry was determined on the basis of 10 oxygen and 2 hydroxyl ions, such as with the following structural formula: (K, Na)1-z Al2-x (Mg, Fe(tot))x (Al1-x Si3+x O10) (OH)2, z = H3O+ From the determination of the frequency position of the AlVI-O-Si deformation vibration (in the range of 550-510 cm-1), the x value is obtained, which allows the chemical composition of the basic lattice (tetrahedron-octahedron tetrahedron) according to the above formula. The determination of the Mg content from the correlation between the measured Mg value (with ICP-AES) and the quantitative infrared spectroscopic determination of the illite (in the range of the OH valence vibrations) results in the Fe(tot) value of the octahedron. In the same way, the quantitative ratio of the interlayer cations K and Na is determined.

The study area is located in the Varzeghan city and in the province of the East Azerbaijan. Mineralization in the Hizeh – Jan area is gold mineralization type and associated with quartz and quartz-carbonate veins and veinlets, which is occurred in the Eocene volcanic rocks with andesite composition. The most significant alteration in this area, is developing of propylitic, argillic and silicic alterations. Based on the breccia, comb, overgrowth textures of quartz and carbonate gangue minerals of these veins, type of sulphide minerals include pyrite, galena, sphalerite, chalcopyrite, tetrahederite, kaolinite and montmorillonite minerals that formed in argillic alteration and more focus of mineralized veins near the micro-diorite dikes demonstrator of IS epithermal gold mineralization occurred in this area and bivariate statistical analysis confirm the genesis of gold and associated elements in a different phases. In this area, alteration geochemistry studies corresponded with microscopic studies and XRD analysis.

The study area is located about 25 km northwest of Takestan city, within Tarom-e-Sofla metallogenic belt. This area is covered by a widespread Eocene andesite to dasite volcanic rocks affected by Oligo-Miocene monzogranite to granodiorite igneous bodies which altered them to silicic, argillic zones as long as hypogene sulfide vein-veinlet mineralization (e. g. galena, sphalerite, pyrite, rare chalcopyrite and tetrahedrie-tennantite) occurred along with supergene minerals (e. g anglesite, cerussite, malachite, covellite and goethite in oxide zone). This study concentrated on geochemistry and geo-barometry of sphalerite and galena to evaluate sulfidation state, temperature and type of ore formation. During mineralography studies, two types of galena were recognized: 1) high temperature, brecciated veinlet type including tetrahedrite and, 2) low temperature coarse grained type along with colloform sphalerite. Based upon mineral chemistry of sphalerite, average concentration of Cd, Ga, Ge, Zn/Cd and Ga/Ge ratios were 5870, 970, 1380, 165. 4 and 1. 39, respectively. Ga/Ge ratios of sphalerites geothermometry indicate that the formation temperatures of sphalerite are between 170° C and 220° C. The amount of log aS2 hydrothermal fluid (-11. 5 to-13. 5), calculated from FeS content (0. 33-0. 80 mol%) in sphalerite, can be attributed to moderate sulfidation state for changoreh deposit. According to Sb/Bi in galena geo-thermometer, geochemistry of sphalerite (low

Part of the Ultramafic Sorkh-Band complex along the Kahnuj, Roudan, Minab Ophiolite belts Hormozgan Province at Nazdasht area, contain harzburgaite, dunite, and serpentinit (with dominance harzburgaite). The major mineral in these rocks included olivine, orthopyroxenes and minor mineral such as Spinel. Mesh and granoblastic texture is dominance in these rocks and tectonic pressure effect can be seen as kink band and undulose extinction within the minerals. Results from Electron Microprobe analysis of minerals show olivine with (Fa 90. 18-93. 6) forsterite composition and rich of magnesium that belong to Alpine type. Also orthopyroxenes show (En 32. 8-95. 2) enstatite composition and spinel Cr# (53. 9-71. 02) have chrome. The harzburgites have high Mg# (97. 78-84. 65) but are poor of Al2O3 (0. 71-0. 34) and Ca (0. 69-0. 45), which can be said these rocks are refractory waste that have been remain after the partial melting of more than 25% percent. Low amount of Al and Ti (0. 01-0. 04) in spinel existence at the Nazdasht harzburgites consider to be characteristic of supra-subduction zone peridotites.

The alkaline and stratoid volcanic rocks of Separdeh district (NE Qazvin), located on the central Albroz zone, are underlain conformably by Early Cretaceous limestones of Tizkuh Formation. These rocks are texturally homogenous and very fine-grained and characterized by microphenocrysts and microliths of plagioclase, pyroxene, olivine, apatite and opaque set in a hyaline matrix. However, few pyroclastic deposits with the following characteristics are found amongst them: patchy fabric, mafic micropillows, relative high vesicularity (3-4 times of lava flows), segregation vesicles, pumiceous clasts and glassy shards. So, in contrary with the effusive lava flows, it can be concluded that they were formed by more explosive eruptions. The samples are tephritic in chemical composition and belonged to the sodic alkaline suite. Although the effusive samples have a similar chemical composition, the pyroclastic samples show higher contents of silica and alkalis and lower amounts of TiO2, Fe2O3 t, MgO and CaO than the effusive lava flows. Also, most samples show an enrichment (about 100 times) of LREEs relative to HREEs, positive anomaly of HFSEs, Th, Rb and Eu, negative anomaly of Ta and K and also no anomaly of Ti and Nb. Moreover, they set in the continental rift setting and show an enriched garnet lherzolite source in the petrogenetic plots. As a result, it can be stated that the parental magma originated from an enriched asthenospheric mantle were effusively erupted in a deep submarine basin through the fissures of an extensional regime (or continental rift setting) during Late Cretaceous times. However, the more acidic magma could be produced by partial melting of lithosphere due to invading of the mantle mafic magma. Sometimes, the styles of eruptions were changed into the more explosive activities by mixing of two magmas intensified by contact with water.

Mahmoudabad metamorphic complex is a part of Sanandaj-Sirjan metamorphic zone that cropped out in SE Shahindezh. Metapelites are the main lithology of Mahmoudabad complex and there are restricted exposures of foliated and granoblastic metabasites present in this complex as well. Metabasites of this complex are investigated in this research. Metabasites display amphibole and plagioclase mineralogy that indicating amphibolite facies. Chemical composition of plagioclase is andesine and labradorite and amphibole is magnesiohornblende and tremolite. Thermobarometry results, that calculated by different methods, display temperature between 430 to 750 centigrade and pressure 6 to 13 kilo bars that are almost equivalent geothermal gradient between 20 to 25 centigrade per kilometer. According to the whole rock geochemical data, the amphibolites of Mahmoudabad complex are orthoamphibolite type and are mostly basaltic in composition. Geochemical signatures of these amphibolites are compatible with tectonic setting of continental back arc. Probably, Mahmoudabad complex amphibolites, are indication of mafic magmatism in the continental back arc setting, arisen from Neotethy oceanic basin seduction beneath continental lithosphere of Sanandaj-Sirjan, that have been experienced collision or continental active margin metamorphism.

The Jebal-E-Barez Oligocene granitoid is located in the southeastern Bam, and in the southeastern part of the Urumieh-Dokhtar Magmatic Assemblage. Based on petrographic studies, this granitoid includes tonalite, granodiorite, granite and alkaligranite, which are composed of quartz, plagioclase, amphibole, biotite and alkali feldspar. The albite of plagioclase ranges from 38. 38 to 67. 26 percent, and its composition is oligoclase to andesine. Composition of calcic amphiboles varies from magnesiohornblende to tschermakite, which is feature of I type granite. The Na2O amount and calc-alkaline nature of amphiboles indicate subduction zone for this granitoid, furthermore Al2O3, TiO2 and Mg# amounts of amphiboles indicate crust and mantle mixing in the formation of granitoid magma. The geobarometry studies clarify that hornblende crystallization occurred in 2 kb, in addition to the geothermometry studies on aluminum of amphibole and hornblende-plagioclase pair minerals display crystallization temperature average of Jebal-E-Barez granitoid is 800 oC. Jebal-E-Barez granitoid ƒ O2 determine magma oxidation state.

Detailed microstructural analysis has been conducted in the Ghandab metamorphic Complex, which is one of the most important high temperature – low pressure regional contact metamorphism studied areas in Iran. Textural evidence suggests the sequence of growth of minerals with increasing metamorphic grade and during development of a crenulation foliation. The sequence of mineral growth is considered to be cordierite, andalusite, garnet, and sillimanite. The first foliation (S1) is preserved largely as inclusion trails in cordierite porphyroblasts. However, garnet and andalusite porphyroblasts are syndeformation crystals and grow during development of crenulation-foliation of S2. According to textural evidence, sillimanite produced late in the thermal history of metamorphism and deformation.

The Ghoznavi coal mine, as an active mine in Golestan Provice, is located about 45km south of Azadshahr. Coal extracted from first (I) and third (0) coal layers. XRD and SEM/EDS studies indicate the presence of quartz and clay minerals as major and pyrite (arsenopyrite), gypsum, jarosite (natrojarosite), goethite, hematite, plagioclase, K-feldspar, rutile and corundum as minor minerals. After coal formation, jarosite, natrojarosite, hematite and goethite were formed due to the alteration of primeray iron-bearing minerals, such as pyrite. Berlinite, rutile, corundum, plagioclase and K-feldspar are not syngenetic minerals in the studied coal and they were transported from the outside to the sedimentary basin during precipitation of the organic materials. Presence of the quartz, plagioclase, K-feldspar, rutile and corundum seem to be generated from older igneous units such as Soltan Meydan basalts and alkaline granite in the Khoshyeilagh region, which are transfered to the lagoon. There are two generations of pyrite in the coal layers, including syngenetic euhedral pyrite, which is distributed throughout the coal matrix, and subhedral to anhedral pyrite as fissure filling. FT-IR study shows the presence of silicate and clay minerals, aromatic C=C stretching vibration related to the organic materials, and OH-bands related to the OH-bearing minerals.

Organic-inorganic perovskite (CH3NH3PbI3), due to an appropriate energy gap to absorb sunlight, is used as an absorbent layer in third generation solar cells. Crystallinity of light absorbing layer plays an important role in the performance of perovskite solar cells and substrate plays an important role on crystallinity of light absorbing layer. In superstructure solar cells, alumina (aluminum oxide) is used as the substrate of light absorbing layer. In this paper, alpha and gamma aluminum oxide are used as the substrate of perovskite layer. The effect of this work on the crystallinity of perovskite layer and parameters that affect the performance of solar cells have been investigated. It was found that by taking into account all the parameters that affect the performance of solar cells, alpha phase aluminum oxide to the gamma phase is more suitable for use in perovskite solar cells that fabricated by two step deposition.