IRANIAN JOURNAL OF CRYSTALLOGRAPHY AND MINERALOGY
Year:2024 | Volume:32 | Issue:1|Papers Count:14

The South-Gharezagh intrusive exposed in northwest of the Sorsat metamorphic complex, which is structurally a part of the Sanandaj-Sirjan zone. Intrusive of South-Gharezagh is located in the shear zone and are mylonitized. Morphologically, the crystallization of zircon in the intrusive and mylonitic mass of South-Gharezagh includes {110} prisms and {211} pyramids, which indicates their crystallization from S-type magmas. The crystallization temperature is calculated to be 698 to 770 ◦C, based on the morphology of zircon, in the massive and mylonitic parts of the South-Gharezagh massif, zircon saturation thermometry and geochemistry of the whole rock. In addition, the thermobarometric chemistry of biotite mineral has been calculated at a temperature of 677 ◦C and a pressure of 0. 8 kbar. The petrofabric evidence shows that chemical and petrofabric changes have been gradually occurred along with the deformation progress in mylonites. As a result of petrofabric, the recrystallized quartz grains and the migration of the grain boundary in the recrystallization is clear, which indicates a change in the facies of the green schist metamorphism.

The Lalezar igneous complex is located on the border of the Sanandaj-Sirjan zone and the southeastern parts of the Urmia-Dakhtar volcanic arc and in the northeast of Baft city in Kerman Province. In the northwestern and western boundaries of the intrusive body, there are relatively wide contact metamorphic carbonate rocks. In the southern part of Hararan, the Lalezar igneous body with the Oligo-Miocene limestone and marl complex (equivalent to the Qom Formation), as large contact with metamorphism halo (skarn and marble parts), is the most widespread. Based on microscopic studies, garnet, calcite, wollastonite, pyroxene, olivine, idocrase, and epidote minerals are formed in skarns. Different metamorphic zones including garnet-clinopyroxene, olivine-clinopyroxene, wollastonite-garnet, and garnet-epidote have appeared. Based on the geochemical analysis of the minerals (EPMA), the garnets contain more than 70% grossular (calcium-rich garnet) and less than 30% almandine (iron-rich garnet). The composition of clinopyroxenes belongs to the first group (calcium-iron and magnesium) and of the wollastonite-enstatite type, where the amount of wollastonite is more than 50%. Also, there is less than 10% ferrosilite in the composition of these clinopyroxenes. Based on the garnet-clinopyroxene temperature-pressure measurement, the temperature of skarn formation, based on various equations presented, is between 413 and 530 degrees Celsius and the pressure is 1. 5 to 2. 5 kbar. The existing paragenesis as well as thermodynamic conditions indicate oxygen fugacity greater than 0. 2. This phenomenon indicates the activity of fluids rich in silicate-rich solutions in the formation of these skarns.

The studied area is located in the northwest of Iran, south of Ardabil Province, in the Alborz-Azerbaijan zone. The important volcanic phases in the region, based on K-Ar dating, include three sequences: Eocene (trachyandesite), Oligocene (basalt, basaltic andesite) and Miocene phase (basaltic andesite, basaltic trachyandesite and rhyolite). The Eocene sequence shows the nature of shoshonite and the Oligocene and Miocene sequences show the nature of calc-alkaline to calc-alkaline perpotassium. All three sequences in multi-element diagrams normalized to the primary mantle show negative Nb-Ti-Ta anolalies, depletion in Y, Yb, Ti and enrichment in Rb, Ba, K, Th. Most likely, the slab break-off of the Neotethys subducting plate, as a result of the creation of an asthenospheric window in facilitating the partial melting process, has caused the partial melting of the metasomatized continental lithospheric mantle and the formation of the Eocene-Oligocene volcanic sequence. The source of heat for Miocene-Quaternary volcanoes is also related to the rise of the asthenosphere, which is caused by the delamination of the lithosphere. Using this study, we improve our understanding of the nature, origin and magmatic evolution of the igneous rocks of northwestern Iran, which are influenced by geodynamic environments.

The Tatros kaolin deposit (southwest of Dansfahan, Qazvin Province) is a product of the alteration of rhyodacitic volcanic rocks of the Middle Eocene age. Mineralogical studies show that kaolinite and quartz are the main mineralogical phases and illite, rutile, pyrophyllite, dickite, alunite, and chlorite are accessory mineralogical phases of this deposit. The decrease in the chemical index of alteration (CIA) and the increase in the ratio of (SiO2+Fe2O3+MgO+CaO+Na2O+K2O)/(Al2O3+TiO2) from the center to the outside in the studied profile indicates the existance of alteration and hydrothermal zoning in this deposit. The distribution pattern of rare earth elements (REE) normalized to chondrite indicates the strong diferentiation and enrichment of light rare earth elements (LREE: La-Eu) related to heavy rare earth elements (HREE: Gd-Lu) and the occurrence of strong negative Eu and Ce anomalies in the studied kaolin samples. Calculations of mass changes assuming Ti as an immobile monitor element show that kaolinitization of rhyodacite rocks is accompanied by enrichment of elements of Al, Sr, Zr, Hf, Ta, Nb, U, Th, Y, La, and Pr, leaching-fixation of Sm, Nd, and HREE, and depletion of Si, Fe, Mg, Mn, Ca, Na, K, P, Rb, Cs, Ba, Pb, V, Cr, Zn, Eu and Ce. The obtained results reveal that the behavior of elements during the development of kaolinitization processes is controlled by factors such as changes in pH and temperature of fluids responsible for alteration, residual concentrations, surface absorption, scavenging by metalic oxides, and the presence of mineralogical phases resistant to alteration. The occurrence of negative Eu anomaly during kaolinitization indicates the destruction of plagioclase by high-temperature hydrothermal fluids. The presence of diaspore, dickite, and pyrophyllite, the enrichment of LREE related to HREE, the differentiation of HREE from each other, and the occurrence of strong negative Ce anomaly in the studied samples clearly suggest the role of hypogene processes in the development and evolution of the Tatros kaolin deposit. Other evidence such as strong positive correlations (La/Yb)N-LOI and P2O5-LOI along with the values of some geochemical parameters such as Ce+La+Y, Nb+Cr, Rb+Sr, and Y/Ho support this idea.

The Pargeh pluton is located in the northeast of Qazvin. The rocks of this pluton mainly include monzogabbro and olivine gabbro, which mineralogically contain olivine, clinopyroxene, plagioclase, biotite and alkali feldspar. Geochemically, they have features of potassic alkaline magmas with enrichment in large ion lithophile elements (LILE: Ba, U, Pb, Sr) and depletion in high field strength elements (HFSE: Nb, Ti, Zr), which are similar to subduction zone magmatism and mantle-derived magmas. Chondrite-normalized REE plots show enrichment in light REE (LREE) (4. 43< (La/Yb) N <8. 58)) and slight negative anomalies (Eu/Eu* = 0. 82-0. 99). The studied gabbroic rocks have resulted from fractional crystallization of a parental magma which formed by partial melting of depleted lithospheric mantle with spinel-peridotite composition. The primary ratios of 87Sr/86Sr and 143Nd/144Nd (0. 70493-0. 70525 and 0. 51272-0. 51269) are compatible with the parental magma formation in the mantle wedge. The values of ɛNd(i) (1. 47 to 1. 92) are in the range of mantle-derived melts. We suggest that Pargeh gabbroic rocks are part of the Alborz magmatic belt, which according to the geochemical data, their tectonic setting is consistent with a post-collisional, back-arc extensional environment.

The Shafarud Metamorphic Complex is located in the northwestern part of Iran in the Alborz-Talesh Mountain range. Paleozoic metamorphism (Carboniferous-Permian) are the oldest rocks of this region. The eclogites of the Shafarud Metamorphic Complex are exposed as lenses of several meters in size along with serpentinite masses in the basal parts. The mineral assemblage of the eclogites includes garnet, pyroxene, amphibole, white mica, epidote, plagioclase, chlorite, quartz and sphene. SEM images and the results of electron probe micro-analyzer (EPMA) show the growth chemical zoning in garnet porphyroblasts. According to the calculation of the temperature-pressure pattern, using Jacobian transformation, the core and the rim of garnets have been formed respectively at temperature-pressure 600 ºC-18. 2 Kbar (eclogite facies, ~60 Km) and 550 ºC-7. 5 Kbar (green schist facies, ~25 Km). According to the results of this study, the structural pattern of the eclogites of the Shafarud Metamorphic Complex is similar to the alpine type, during which the process of uplift and pressure reduction occurred in almost isothermal conditions due to a rapid uplift.

Arc copper mine is located about 55 km northwest of Birjand city in South Khorasan Province. The rock units at this area include thin to medium-bedded flysch sandstones in red and gray colors with Eocene age. Copper mineralization occurred in the upper part of bleached gray sandstones in a lenticular shape. There are at least two revitalization beds. Each of the horizons consists of three zones: Red Zone, Bleached Zone, and Mineralized Zone. The mineraliztion zone has occurred within the bleached and reductant zone. The texture in this deposit is replacement and scattered grains. The presence of framboidal pyrites in the ore horizons and the intactness of cellular structures replaced by sulfides indicate that this deposit was formed during the early stages of diagenesis prior to deep burial. Based on lithology (host rock from sandstone greywacke to litharnite), mineralogy of mineral (chalcocite, covelite), structure and texture, stratigraphy and factors controlling mineralization (presence of traces and remains of plants as the main factor regenerative environment, appropriate permeability of the host rock) suggest that this deposit is the similar to Red Bed type sedimentary copper deposits.

The studied area is located in the southeast of Shahrood, north Torud, and northeast of the Central Iran structural zone. The area is one of the Iranian basement terrains which include a wide variety of igneous and metamorphic rocks. The study gabbroic bodies form a small part of this complex and their essential minerals are Plagioclase (labradorite, bytownite), pyroxene (calcic group and augite and clinoenstatite composition), olivine, biotite, and amphibole (calcic group and pargasite and pargasite hornblende composition). Based on the chemical composition of minerals, the magma forming of these rocks has calc-alkaline nature and during their crystallization, the fugacity of oxygen has been high. Geothermometry of pyroxene and amphibole suggest crystallization equilibrium temperatures at gabbroic rocks, for pyro, xene are 900-1200°C and for amphiboles are 820-990°C‑ respectively. Geobarometry calculation of these rocks, using an amount of total amphibole aluminum (Alt is between 2-2. 5), estimated between 6. 52 to 8. 9 kbar and for pyroxene between 5 to 7 Kbar. These conditions are equivalent to the formation and final equilibrium at depth of 23 to 27 km of the lower crust.

The granitic gneisses of Abadchi village is located in the north of Zayandeh-Rud dam, and the area is a part of Sanandaj-Sirjan Zone. The mineralogical composition of these rocks are composed of quartz, plagioclase, K-feldspar, biotite, amphibole, muscovite, zircon, titanite and allanite. Quartz crystals, as the most abundant mineral constituents of these rocks, display the different conditions of deformation dynamic on the studied rocks according to their texture. Moreover, quartz crystals show evidences of bulging recrystallization (BLG), sub grain rotation (SGR), and grain boundary migration (GBM). Deformation of quartz crystals depends on the temperature and strain-rate and can be determine using T/strain-rate diagram. Therefore, the fractal dimension at quartz grain boundary sutures is between 1. 23 and 1. 11 and temperatures between 250-400 °C and 500-750 °C in the granitic gneisses. Using the fractal dimension and calculation of temperature, the strain rates are measured 10-11. 6 to 10-6. 6for the four domain of granitic gneiss sample. The results obtained from the diagram are consistent with the deformation evidence of quartz crystals (GBM, SGR, BLG).

Masteroon area is located in the northeast of Azna city, in the Sanandaj-Sirjan zone. The rocks units include a relatively uniform sequence of slate and phyllite with a granodiorite intrusive mass that includes pegmatitic complex. The most important minerals include quartz, alkaline feldspar, plagioclase, tourmaline and muscovite. Quartz is high pure and does not have any other elements. EPMA shows the albite-type feldspar with a lesser extent than orthose-type with a less than 550⁰C crystallization temperature. This can be due to the result of below the freezing of the feldspars composition during the cooling of the mass. The available tourmalines are of schorl and alkaline type with a deficiency in the X position, and their numerous and abundant presence, automorphism and absence of chemical zoning, indicate that tourmalines are magmatic. Muscovites are present in two forms: coarse-grained in pegmatites and fine-grained in joints and cracks, and the coarse-grains does not stretch to phengite.

The Laleh-Zar granitoid complex is one of the most important magmatic phases of the Urumieh-Dokhtar belt and is located in the southeast of this belt in Kerman Province, which has a combination of granite and gabbrodiorite. Parts of this vast complex is exposed in the southern part of Hararan region. Based on petrographic studies, these igneous rocks are granodiorite, diorite, and dacite with quartz, plagioclase, amphibole, biotite, pyroxene, and opac minerals. The secondary minerals of chlorite, calcite, epidote and sericite are also present in these igneous units. The results of mineral analysis, using microprobe method, showed that amphiboles are calcite and hornblende. these amphiboles are igneous and belong to the calc-alkaline magmatic series and are of S type (subduction Amphiboles), which are formed in the subductions environment. The pressure and temperature during the formation of these amphiboles were calculated by different methods, therefore the temperature was 650 to 798 degrees Celsius and the pressure was 0. 9 to 2. 3 kbar. In addition, these amphiboles have high oxygen fugacity and were created at the depths of 9 to 14 kilometers of the earth. Based on the relationships between different elements in these amphiboles, the conducted studies showed that tschermakite and adenitic successions occurred in these amphiboles, but glaucophane, riebeckite and richterite successions did not occur in these amphiboles.

In this research, pure and Ba-doped lead zirconate titanate nanopowders were synthesized by sol-gel combustion in order to investigate their structural, optical and electrical properties. The results of the structural investigations showed that the samples have a tetragonal crystal structure with the crystallite size of about 20 to 30 nm. Cohen's method and size-strain diagram were used to calculate the lattice constants and the average size of nanocrystals, respectively. Transmission electron microscope was used to determine the size and shape of nanoparticles. Optical properties of prepared samples were studied using Kramers-Kronig relations and FTIR technique. The band gap of the samples was obtained about 3. 5 eV using Kubelka-Munk equation. Dielectric constant of pure and Ba-doped samples was obtained 1050 and 570 at frequency of 100 Hz, respectively. SEM image showed the grain size of pure samples is about 2 to 3 μm.

In the present work, yellow apple's skin, red apple's skin and Cercis siliquastrum’s petals have been used as pigments in dye-sensitized solar cells based on TiO2 nanoparticles. These pigments were extracted by a simple heat treatment method. In order to measure the absorption characteristics of pigments, ultraviolet-visible spectroscopy (Uv-Vis) analysis was used. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the structural characteristics and morphology of nanoparticles, respectively. The I-V curves of solar cells were drawn under standard conditions in light and dark states. The results show that the cells made using dyes extracted from yellow and red apple's skins and Cercis siliquastrum’s petals have short circuit currents of 27. 49 μA, 58. 50 μA and 173. 85 μA, respectively, and their open circuit voltages are 0. 53V, 0. 53V and 0. 55V, respectively. Their fill factors are equal to 0. 56, 0. 65 and 0. 68 respectively and their efficiencies are 0. 04%, 0. 08% and 0. 27% respectively.

Bismuth-based lead-free perovskites are considered as a promising alternative to lead perovskite, whose toxicity and instability are a major challenge in their commercialization. However, lead-free provskites are strongly restricted by low efficiency due to the high band gap and poor quality of layer formation in perovskite solar cells. In this research, the double perovskites Cs2AgBiI6 has been synthesized from solution-based synthesis heating under reflux and then the film was deposited on mp-TiO2 substrate by thermal evaporation method. The effects of annealing and thickness on the optical and electrical properties of deposited layer were investigated for using as absorber layer in perovskite solar cells. The optimal thermal annealing temperatures (250 °C) would significantly extended the wide absorption range up to 650 nm and reduces appreciable direct band gap of 1. 92 eV. The results from analysis of the current density–voltage and photoluminescence spectra, show that the best power conversion efficiency of 0. 9% obtained at optimal condition of 250 °C annealing temperature and 400 nm thickness of Cs2AgBiI6 film for using in mesostructure lead-free perovskite solar cells. These optimal conditions are clearly consistent with the charge transfer characteristics and stability of the samples.