مجله بلور شناسی و کانی شناسی ایران
سال بیست و نهم شماره 4 (پیاپی 86، زمستان 1400)

The RoudMajan kaolin deposit is located about 35 km northwest of Torbat-e- Heydarieh city, Khorasan Razavi Province, in the Great Kavir Block subzone. Field evidence and laboratories results indicate that this deposit is genetically associated with the alteration of basaltic andesite rocks (Lower Eocene). According to the microscopic evidence and various analytical techniques (XRD, SEM-EDS, FE-SEM, DTA and TGA), kaolinite, illite, haloysite, quartz, alunite and muscovite are the major mineralogical phases and hematite, pyrite, rutile, galena, barite, calcite, biotite, apatite, titanomagnetite and titanium augiteare the minor minerlogical phases in this deposit. Calculations of mass balance of elements with the assumption of Al, as a monitor immobile element, reveal that the development of the kaolinization process of andesi-basaltic rocks in the RoudMajan  has been accompanied with the enrichment of Pb, leaching of elements such as Cs, Rb, Cu, Zn and Sr and leaching and fixation of elements such as Hf, Ba, Zr, V, Th, Ta, Nb, Ga, Cr, Co and Ni. Among the lanthanides, only Ce experienced mass decrease, while others exhibit both incremental and decremental behavior during kaolinization processes. The distribution pattern of normalized REE to chondrite indicates the differentiation and enrichment of LREE from HREE. The obtained results reveal that the behavior of trace elements during the formation of the RoudMajan kaolin deposit is a function of factors such as changes temperature and mineralizing fluid chemistry, differences in alteration intensity, adsorption, scavenging, mineralogical control, and abundance of complexing ions. Correlation coefficients between elements indicate the role of clay minerals, secondary phosphates, rutile, manganese oxides, muscovite and illite in the distribution and fixation of lanthanides. The occurrence of negative anomalies of Eu and Ce in kaolin samples indicates the alteration of plagioclase minerals of primary basaltic andesite rocks by high-temperature fluids and reduction of oxygen fugacity during the development of the RoudMajan kaolin deposit.

Around The Karik village, east of Meiduk mine, Eocene volcanic rocks (andesitic basalt, andesite, dacite and rhyolite) and pyroclastic rocks (agglomerate and tuff) are exposed. These rocks are cut by several andesitic dikes. The major textures in the volcanic rocks are porphyritic and flow textures. The minerals such as plagioclase, alkali feldspar, quartz, pyroxene, amphibole, biotite and opaque are present as phenocrysts and fine grains. Sometimes, feldspar crystals (mainly plagioclase) are found as oriented microlites. In some cases, within the plagioclase phynocrysts disequilibrium textures such as sieve texture, corrosion and zoning are observed. Quartz crystals are corroded. Amphibole and biotite crystals are changed into Fe-Ti oxides on their rims. These textures are probably attributed to magma mixing, water vapor changes and decompression due to rapid ascent of magma. The Karik volcanic rocks are calc-alkaline and mainly metaluminous in nature. Primary mantle and chondrite normalized multielement diagrams for the study rocks are spiked and they have several peaks and troughs. In the diagrams, the depletion of the high field strength elements such as Nb, Ta, Ti and P is obvious which is characteristic of the subduction magmatism. The sharp positive anomaly of Pb might be attributed to crustal contamination. The chondrite normalized RRE pattern of the study rocks is relatively smooth with enrichment of LREEs relative to HREEs that is due to the high abundance of LREEs in the source or crustal contamination. According to the petrological and geochemical evidence, the Karik volcanic rocks are formed in an active continental margin setting due to the subduction of Neothetys oceanic lithosphere beneath the Central Iran micro–continent.

Arazgoni Kaolin deposit is located in East Azarbaijan Province, about 18 km south of Qara Aghaj, the center of Charoymaq city. The area under investigation, in the geological zoning of Iran, is a part of the Urmia-Dokhtar volcanic-plutonic belt. Most of the study area is composed of volcanic rocks with Oligo-Miocene dacite-andesitic composition which have been strongly altered by hydrothermal alteration. Petrographic observations show that the main minerals in the dacite-andesites are plagioclase, pyroxene, quartz, biotite and alkaline feldspar and porphyritic texture is predominant. XRD analyzes show that kaolinite, albite and quartz minerals are present as the main minerals which accompanied by small amounts of orthoclase, mica, illite, pyrophyllite, montmorillonite and anatase as minor minerals. Aluminum and Silica are used as Determinant factors of Behavior and Quality of Products of Arazgoni Kaolin Samples, according to the ECC global standard, for evaluation of the quality in the ceramic and tile industry. Resistance of ceramic products in Arazgoni samples are high against thermal, tensile and compressive shocks. However, the amount of iron oxides and titanium in Arazgoni ceramic products does not have the desired quality compared to the ECC standard. The amount of potassium oxide in Arazgoni samples, that play a flux role in ceramic products, is within the ECC standard, which has reduced the deformation of ceramic products. The amount of SiO2, Al2O3, K2O and LOI in Arazgoni samples is within the ECC standard for the ceramic and tile industry. Due to the mineralogical and chemical composition of Arazgoni mine soil, it can be included in the group of kaolins that have low thermal expansion coefficient and high dry resistance. This soil, despite having a high viscosity and good dry resistance that it gives to the consumer, does not absorb much water, which causes no lubrication in the slurry and thus increases the consumption of expensive lubricants in the formulation. Very important features of this soil are high linear shrinkage, high dry strength and relatively low coefficient of thermal expansion.

Zavarian epitermal gold (copper) deposit is located in an intracontinental volcanic cone (stratovolcano) with the Early Miocene age, in the middle of the Urmia-Dokhtar magmatic arc. The host rocks of this mineralization include a set of basaltic, andesitic-basaltic, andesitic, dacitic, as well as granodiorite and tonal units that have been exposed in volcanic form (lava and pyroclastic) and semi-deep massifs. These Zavarian gold (copper) deposit is located in the middle of Urmia-Dokhtar magmatic arc, in a volcanic cone with andesite-basalt, andesitic units and granodiorite massifs. This complex has the nature of calc-alkaline and the pattern of changes in rare earth elements (LREE enrichment, LILE relative to HREE, HSFE, negative anomalies of Ti, Nb and low Nb /Y values) of arc-associated magmas. Structural studies point to the key role of right-wing shear zones as controlling sedimentary basins and creating the necessary conditions for local tensions and magma outflows. Dispersion and type of hydrothermal alterations, mineralized veins within intrusions and the presence of magnetite, tourmaline and chalcopyrite show the role of magmatic fluids in mineralization. These fluids have a homogenization temperature between 220° to 350° C and a salinity of 10-15% by weight of salt. Comparison of this mineralization with Sari Gunay deposit in the northwest of Sanandaj-Sirjan zone, the Miocene magmatic phases are related to the formation of shear zones and local tension in post-collision orogenic phases, which increases with the role of fluids. Atmosphere and mixing are associated with magmatic fluids.

In southwest of the Jandaq City (northeast of Isfahan Province) and northwest of the Central-East Iranian Microcontinent (CEIM), the Eocene dykes with trachy-andesitic composition cross cut the quartz monzodioritic intrusion. The texture of these dykes is granular, intergranular and porphyritic. The studied dykes are composed of plagioclase (andesine and labradorite), clinopyroxene (diopside and augite), sanidine, mica (Biotite), and quartz as primary minerals, and amphibole (tremolite-actinolite), chlorite, magnetite and calcite as secondary ones. Mineral chemistry and distribution of elements indicate that these minerals are formed in low to medium pressure (2-5 kbar), 1150 to 1200 °C, and the high Oxygen fugacity conditions. The source rock of the magma is a mantle peridotite which previously metasomatized by fluids and melts derived from subducting oceanic slab.  Mineral chemistry of clinopyroxene and biotite reveal that these dykes have calc-alkaline nature and are formed in a subduction-related environment.

The Zarrin granitoids is located in the west of Yazd block, Central Iran. Zarrin granitoids exhibit mylonitic rocks ranging from protomylonitic to mylontic. In Zarrin granitoids examples of sub-magmatic, microstructures are represented by chessboard patterns in quartz and sub-magmatic fractures in plagioclase, indicating deformation at high-temperature conditions (T > 650º C) and the presence of melt. Some microstructures such as feldspar bulging, quartz grain boundary migration, and subgrain rotation recrystallization imply solid state-high temperature deformation (T > 450º C).  Solid state-low temperature deformation microstructures (T < 450º C) include mica kinks, quartz bulging, feldspar twinning and bending. Sequence of microstructures from sub-magmatic to low-temperature solid-state deformation revealed shear-related deformation at developed during cooling of granitoids at different times and depths. Further, it shows overprinting of low temperature microstructures on earlier sub-magmatic and HT sub-solidus microstructure indictes. Zarrin granitoids recording deformation in the presence of a residual melt during crystallization by submagmatic microstructures and the full crystallization and cooling of the magmatic body by low temperature microstructures.

The amphibolites of east Salmas, as one of the widest units of the metamorphic complex, are located in the northwest of Sanandaj-Sirjan zone, which according to field studies are mainly oriented and foliated amphibolites. Based on microscopic studies, amphibolites include amphibolites, biotite-amphibolites, epidote-amphibolite, biotite-epidote-amphibolite, tremolite-actinolite-amphibolite, and biotite-clinopyroxene-amphibolite. Amphibolite specimens of the region have maximum parallel pattern based on the variation diagrams of rare earth elements normalized to chondrite, EMORB and primary mantle and are similar to intra-plate basalts in terms of geochemical properties. According to the results of whole rock chemistry, the study amphibolites are mainly ortho-amphibolites with a basaltic protolith and calc-alkaline magmatic series, which are located in the intra-plate tectonic position.

Ramand area is located about 80 km south of Qazvin Province, northwest of Central Iran. The study area is a part of the magmatic belt of Orumieh-Dokhtar of the structural zones of Iran. The area consists of rhyodacitic igneous rocks, rhyolite, rhyodacitic tuff, crystalline tuffs and rhyodacitic flow lavas. The pyroclastic and volcanic units are interrupted by major faults such as Korcheshmeh and Hassanabad faults as well as sub-faults with a northwest-southeast trending. The most important alterations in the area includes sericitization, argilitization and hematization. The main ore minerals include pyrite, oxides and iron hydroxides. The most associated gangue minerals are quartz, potassium feldspar, albite and rock fragments in tuffs. In order to determine the properties of mineralizing fluids, fluid inclusions within quartz were analyzed, which are closely associated with gold mineralization in the area. The results of these analyzes show that the salinity of the fluids involved in the quartz minerals varies between 2 and 11.7 wt% NaCl equivalent. Also homogenization temperature of fluid inclusions for quartz varies between 141 and 230 0C. Most of the fluid inclusions in these veins are liquid double phase (L+V) and have sizes smaller than 20 micron. The analytical results of the analyzed samples show low temperature and salinity range which is consistence with metamorphism and basin brine sources. The fluid inclusions, mineralogical and geochemical data show that the gold mineralization in the Ramand area is similar to Epithermal type.

Sahneh, Harsin-Nourabad ophiolits (Kermanshah Provience) located in outer Zagros ophiolitic zone and are parts of the Cretaceous ophiolitic belt, as remnants of southern branch of the Neo-Tethys Ocean obducted over the Arabic–Tauric platform from Oman to northwestern Syria, Cyprus and Antalya. Calculation of Fe/Mg separation coefficient of olivine indicates the mantle origin of this mineral. Textural evidence of ultramafic rocks displays clear evidence of cooling with decompression, partial melting and melt-rock reactions. Tectonomagmatic discrimination diagrams show that peridotite samples are located in olivine- spinel mantle array and SSZ peridotite field. Based on geothermobarometry calibration the temperature and pressure of crystallization of harzburgite and lherzolite rocks were 1100 to 1500 ° C and 12 to 18 Kbar and the wehrlite sample was 1200 to 1500 ° C and 21 to 23 Kbar, which corresponds to the SSZ tectonic environment.

The Lar igneous suite occurs in the central part of the Sistan suture zone, about 22 km north of Zahedan. The suite comprises varied intrusive, hypabyssal and extrusive silica under saturated to silica saturated rock types including syenite, shonkinite, lamprophyres, monzonite, tuff and breccia. Stock-like monzonitic bodies crops out mainly in the south-southeast and northern parts of the suite. The study rocks are quartz monzonite to monzonite in modal composition with porphyritic texture including alkali feldspar, plagioclase, quartz, amphibole and biotite. Their high SiO2, Al2O3, K2O and K2O/Na2O classify them as silica saturated metaluminous, shoshonitic and Roman Province type potassic monzonites. Decreasing in FeO, CaO, MnO, TiO2, P2O5 and MgO concentrations, during magma evolution, represent the fractionation of Ca-plagioclase, apatite and titanite along with mafic crystals from their parental magma. Geochemical studies reveal that partial melting, in comparison to differentiation processes, has been more effective on their geochemical features. Monzonites in the Lar igneous suite show LREE and LILE (except Ba) enrichment and HFSE (Nb, Ta, Ti and Zr) depletion. Negative anomalies in Ba, Nb, Ta and Ti, and high Ba/Nb ratio in these rocks represent their relation to subduction processes. They classify, due to their high K2O and K2O/Na2O ratio, Sr/Y adakitic ratio and post collisional affinities, as continental or C-type adakites. Listric-shaped REE profile, Nb/Ta ratios similar to continental crust and positive correlations between La/Yb and Sr/Y ratios all indicate partial melting of amphibole-bearing lower continental crust. Moreover, high Th and Ni concentrations, Ce negative anomaly, Nb/U ratios similar to subducted sediments and also Mg# higher than 45 probably reveal that not only magmas with geochemical signatures similar to composition of subducted sediments have been contributed in the formation of lower continental crust but also the later have been delaminated or foundered and it’s resulted melts, en route to surface, have inherited some peridotite geochemical signatures.

The Tekieh intrusive complex is located in S-Qorveh in northern parts of the Sanandaj-Sirjan Zone. In this collection, the granite inclusions located in the granite host compound have a diorite composition and the inclusions located in the monzonite host compound have a gabbroic composition. The enclaves are scattered in rounded and elliptical shapes in the host rocks. Generally, they have a sudden contact with the host rock and are composed of igneous minerals. Amphiboles are calcic-type, and their composition is magnesio-hornblende and actinolite. The plagioclases have a range of composition from oligoclase to andesine and oligoclase to bytownite for host rock and enclaves samples, respectively. Based on geothermobarometry studies on amphiboles and also amphibole-plagioclase pairs, the temperatures of 660-5540C and 742-5920C with pressure ranges of 0.3 to 3.62 and 0.21 to 1.8 Kbar were estimated for host rock and diorite enclaves samples, respectively. Oxygen fugacity was high in magma that is consistent with calc-alkaline nature and the formation of rocks in its subduction setting.

Eshkaftouk bentonite mine is located in the northwest of Birjand and eastern part of Lut block. This bentonite is the product of alteration of Tertiary andesitic lavas and associated tuffs. Geochemical characteristics show that bentonite parent rocks have andesitic composition and bentonite samples have andesite to dacite-rhyodacite composition.The magmatic series of all samples is calc-alkaline type. Mineralogical analysis (XRD) shows that the main minerals forming of bentonites include montmorionite, anorthite, cristobalite, and quartz with small amounts of illite, muscovite, kaolinite, microcline and dolomite. Electron microscope images of bentonite samples show that smectite (montmorionite) is the most abundant mineral in these samples that are characterized by flaky morphology with rugged edges, honeycomb and cornflake. The results of energy dispersive spectroscopy (EDS) studies also indicate that the predominant mineral forming  of bentonites is sodium-calcium montmorionite, and accordingly, Eshkaftouk bentonite is Wyoming-type. Investigation of mass changes of major and trace elements of Eshkaftouk bentonite indicating loss of K2O, Na2O, CaO, MgO,MnO and LILE such as Ba, Rb, Sr and gains of SiO2, Al2O3 and Fe2O3.

The Pillow lava and diabase dykes of the southwestern region of Aleshtar are host different species of zeolites and secondary minerals. Zeolites are formed by the cavities and veins and decomposed from primary minerals. Based on field studies, X-ray diffraction (XRD) and Electron Microprobe Analysis (EPMA), natrolite zeolites (most abundant zeolites), mesolite, scolecite and analcime have been identified in the pillow lava and diabase dykes in the study area. The average Si/Al ratios for natrolite, mesolite, scolecite and analcim are 1.46, 1.49, 1.62 and 2.29, respectively. These zeolites are formed during two stages of metamorphic hydrothermal fluids, during fractures and in the cavities of host rocks and at temperatures below 250 °C. The investigation of the geochemical properties of zeolites host rocks, shows that their magmatic series is calc-alkaline to tholeiitic and their tectonic environment depends on the mid-ocean ridges (MORB).

Oxygen fugacity (fO2) and zircon crystallization temperatures (Ti-in-zircon) of ore-bearing quartz monzonite intrusive rocks of ChahShaljami and Dehsalam Cu-Mo porphyry deposits were measured by using calculations of zircon trace element values and oxidation conditions of parental magma were investigated. The Ce4+/Ce3+ values for ChahShaljami and Dehsalam are in a range of 8 to 295 with an average of 125 and 3 to 171 with an average of 35, respectively, therefore they were not in the favorable range for porphyry mineralization. The estimated fO2 values for ChahShaljami and Dehsalam are in the range of ∆FMQ -1.8 to MFMQ +0.6 with an average of ∆FMQ -0.6 and ∆FMQ -1.3 to ∆FMQ -0.4 with an average of ∆FMQ -0.8 which is at least ∆FMQ +1 less than the values of porphyry copper mineralization in the world.. Based on the zircon log fO2 values of ore-bearing intrusive rock, the parental magma originated from partial melting of supra-subduction mantle peridotite zone within oceanic slab. Melting under unfavorable conditions (under magnetite-hematite (HM) buffer and in faylite-magnetite-quartz (FMQ) buffer condition, and lack of sufficient Cu and sulfur at the source), which is supported by evidences in deposit such as lack of magnetite-hematite intergrowths, was not ideal for porphyry Cu porphyry mineralization in the two regions. The results are supported also by previous whole-rock major and trace element geochemistry and Sr-Nd isotopic values.

In this research, MASnICl2 and FASnICl2 thin layers were synthesized by the one-step spin coating method, and then their structural, optical and electrical properties were investigated. The study of these samples (structural properties) showed that the layers have a tetragonal structure (α- phase perovskite), and with the change of organic cation, the crystallinity and morphology of the layers significantly change. These changes also have influences in the optical and electrical properties of the samples. The perovskite layers have a high absorption coefficient (of the order of 105 cm-1) in the visible range. The bandgap for the FASnICl2 layer was 1.48 eV and for the MASnICl2 layer was 1.54 eV. A strong peak close to bandgap was observed in the room temperature PL of the layers, which was remarkably more intense for the FASnICl2 sample. This study showed that the FASnICl2 layers have better crystallinity, lower electrical resistance, higher optical sensitivity and acceptable optical response comparing the MASnICl2 layers, and therefore, they can be suitable options for use as an adsorbent layer in perovskite solar cells.

In this paper, a comprehensive study of structural and elastic properties of MnFe2-xCoxO4 (x = 0.00, 0.40, 0.80, 1.20, 1.60, 2.00) nanoparticles, prepared by citrate-nitrate methodhas, been carried out. Samples were structurally analyzed using X-ray diffraction and Rietveld refinement. The results showed that the structure of the samples could be indexed in cubic symmetry with the space group Fdm, which is confirmed by Fourier transform infrared spectroscopy. The values ​​of the elastic constants of the samples were calculated using the values ​​of the structural parameters as well as the frequencies obtained from the infrared spectrum of the samples. The values ​​of shear and transverse wave velocities obtained from force constants were used to determine the values ​​of Young's modulus, rigidity modulus, bulk modulus, and Debye temperature. The change in the elastic values ​​of the studied samples can be explained in terms of the presence of Co ions and the bond lengths obtained from the Rietveld method.