مجله بلور شناسی و کانی شناسی ایران
سال سی‌ام شماره 4 (پیاپی 90، زمستان 1401)

Siajak area is located within the Sistan suture zone in the south Zahedan. The rock units of the area include metamorphic, sedimentary and intrusive. The amphibolite unit is the most lithologic unit present in this area. The most important alterations in the area are silicification and propylitic alterations. Mineralization is seen with NW-SE and E-W trending in the amohibolite host rock as quartzite + chalcopyrite + pyrite veinlet and quartz + goethite vein. The chalcopyrite and pyrite are primery minerals and covellite, chalcocite, malachite, azurite, hematite and gotite are secondary. Based on the results of geochemical analysis, the highest amount of copper is 3.2%, lead and zinc are 218 and 150 ppm and gold is 174 ppb. Based on the fluid inclusion microthermametry, the homogenization temperature is 163-300 °C and salinity is 10-13.5 wt.% equivalent NaCl. Temperature decreasing is the most important factor for deposition of sulfide minerals. Based on the temperature and salinity of the ore-fluid, the structural control of the mineralization, the type of alteration and its development, and simple mineralogy, the Siajak area is copper vein type.

Ahar area is a part of the Arasbaran metallogenic zone in northwestern Iran, where numerous hydrothermal Cu-Au deposits have been formed. In this regard, Safikhanlu, Niaz, Mazraeh, Anjerd and Kujanagh deposits, as representative deposits, have been observed and structural measurements were performed in the field. In this area, Cretaceous limestones along with volcanic rocks are exposed as the oldest rocks in the region along with Eocene latite-andesites. These volcanic rocks have been intruded by Oligocene plutons such as Safi Khanlu with the combination of granite-quartz monzonite and Khan Kandi with the combination of Monzonite-Gabbro, causing phyllite, argillic and siliceous alterations in Safi Khanlu, extensive argillic alteration in Kujanagh and potassic in the Niaz  area. With a time interval, magmatic activity in the Late Miocene-Pliocene resumed and caused phyllic and propylitic alteration in the Mazraeh and argillic, phyllic, propylitic and potassic in Anjerd area. These alterations were studied using ASTER satellite images and PCA and SAM methods. Then, with field studies, the trend of major fractures in each of the mentioned deposits was determined and compared with the results obtained from remote sensing. The structural analysis showed that the predominant trend of mineralization and alteration zones in the studied deposits is northeast-southwest and is consistent with the predominant trend of the fault lines extracted from satellite images. Based on these results, it can be concluded that fault and fracture have played a major role in controlling and forming gold and copper reserves in the Ahar region.

The study area is located near the Zeinabad village, NW Tabriz. Precambrian to Cretaceous sedimentary units form the dominant outcropping rocks in this area. The investigated basic rocks including lava and diabasic dikes are intruded within the Late Triassic-Early Jurassic sandstone, conglomerate and shales of the Shemshak Formation. The basic rocks are extremely alterated and have abundant vesicles filled by secondary minerals of chlorite, calcite, Zeolite and opaque phases. Petrographic studies of the basic rocks reveal that the plagioclase forms the main constituent mineral and Fe-Mg bearing minerals (most probably hornblende) are completely altered to the calcite, chlorite, epidote and opaqe phases. The most significant textures are porphyry, glomeroporphyry, amygdaloid, sieve and sub-ophitic. Geochemically, the basic rocks are basalts with alkaline signitures. On the basis of variation diagrams, the compositions of analysed rocks are rich of U, Th and LILE (such as Ba, Rb). Positive anaomaly of Pb in these diagrams can be interpreted by the continental crust distribution and/or mantle wedge metasomatism related to the released fluids from subducted oceanic crust. Considering the REE diagrams, the rocks are rich in the LREE but poor in the HREE. High La can be related to Yb contents and can be interpreted to reveal their formations from the garnet bearing mantle sources. Tectonic setting of Zinabad basic rocks is determined as within plate setting. They form in relation with the extensional phases after continental collision during Cimmerian Orogeny in the Azarbaijan continental crust, NW Iran.

A significant characteristic distinguishing sediment-hosted disseminated gold deposits (i.e. Carlin-style) from other Au deposits is the abundance of invisible Au-nanoparticles in the Fe-As-S ores (e.g., arsenian pyrite). In this study, we used the focused ion beam combined with scanning electron microscope (FIB-SEM) techniques, and a high-resolution transmission electron microscope (HR-TEM) to examine invisible Au and how it evolved through later geologic events that eventually led to the formation of Zarshuran gold deposit. This electron examination was performed on auriferous arsenian pyrite (Py4) of Zarshuran deposit with colloform texture and average content of Au (21 ppm) and As (2.4 wt%). Results concluded that the post-ore magmatic-hydrothermal events after configuration of main orebody of the Zarshuran initiated the annealing of the ionic Au-bearing arsenian pyrite, leading to the redistribution of trace elements and specially formation of Au-bearing nanoparticles. High-angle annular dark field (HAADF) images show gold ions present in a undersaturated hydrothermal fluid, resulting in a gradual annealing process of gold nanoparticles (<100 nm in size) in the nanopores and stacking faults of arsenian pyrite crystals, which have taken place and the occurrence of this continuous cycle has led to the formation of Zarshuran world-class ore deposit.

In the south and south east of Kaleybar city, lamprophyric dykes associated with basanitic and andesitic dykes intruded in the Cretaceous-Paleocene flysch-type and volcanic rocks. The lamprophyric dykes show typical lamprophyric texture with biotite and pseudomorphs of clinopyroxene phenocrysts. According to mineralogy and geochemistry, the studied lamprophyres belong to calc-alkaline group and are minette. The studied lamprophyres show enrichment in the large ion lithophile and light rare elements and depletion in the high field strength elements. Geochemical features of the studied lamprophyres confirm that they are originated from 1-3 % partial melting of a garnet lherzolite mantle source with phlogopite veinlets that previously have been metsomatized by subduction related melts. According to biotite crystals Ar-Ar dating, the studied lamprophyres emplaced during Middle Oligocene (31-32 Ma.) in a volcanic arc tectonic setting.

Alam-Kandy iron skarn lies at the contact margin of a granodiorite stock with limestone and dolomites of Soltanieh Formation. Anhydrous prograde calc-silicate assemblages (garnet, diopside, wollastonite) were replaced by a series of hydrous calc-silicates (serpentine, epidote, tremolite-actinolite) and/or quartz, calcite, magnetite, hematite, and pyrite. During this event, magnetite lenses (±hematite and pyrite) are formed with various textures such as massive, banded, scattered grains and veins at the vicinity of the intrusion body and the contact zones. According to this study, The geochemistry of trace elements of magnetite is variable under the influence of progressive and regressive stages of skarn formation and wall rock composition, and consistant with the indicators of magnetite formation in the (magnesium) skarn environment. These include factors such as: 1) high concentration of Mg (1 to 1.5 %), low values of Cr (<10 ppm), Ti (<0.01%) and insignificant incompatible elements such as Ag (0.5 ppm) 1 <), Rb (ppm 1 <), Sb (ppm 1 <) and Na (less than 0.1%) in magnetite; 2) significant positive correlation between Ti and V and the position of the samples in the Ti+V versus Ca+Al+Mn and Ni/(Cr + Mn) diagrams. High temperature vein-veinlet magnetites have more cobalt content than the replacement magnetites syn-deposited by sulfide minerals (retrograde stage), indicating that in the Alam Kennedy skarn system, the concentration of cobalt in the magnetite is controlled by the abundance of sulfide mineral deposits.

The Iron-apatite deposits of Choghart and Chadormalu mining district are located in the western margin of the Bafq block and are hosted by Precambrian metamorphic basement complex, Late Precambrian sedimentary-volcanic units, and Late Precambrian-Early Cambrian plutonic rocks. The origin and relation of the rocks for a long time, which are known as metasomatites, have always been questioned. Based on petrography and mineral chemistry studies, five types of hydrothermal alterations have identified in these rocks. The oldest one is Na-alteration, which occurs at farther distances of iron deposits and is characterized by the presence of chessboard albite. The youngerst one is sodic-calcic alteration which is widespread and two-stages of the metasomatism model are characterized by the presence of tremolite-actinolite and is synchronous with the Fe-oxides. Potassic alteration occurs after two previous alteration phases, because of the influence of K-rich fluids and the formation of K-feldspar and secondary biotite. Silicate and sericite alteration has occurred as a late phase in the region.

The Kamar-Gov study district is located south of Hashtjin city in the Ardabil Province (NW Iran). The geological units in this district include lavas (with composition of basaltic trachy-andesite to rhyolite), sub-volcanic rocks (as dyke and stock with composition of porphyritic trachy-andesite and trachyte) and crystal, vitric (lithic) tuffs (intermediate and felsic composition). Extensive zones of silicic, sericitic-argillic, advanced-argillic, and chloritic alteration have formed in these rocks. Pyrite is the prevalent metal mineral in the study area and approximately extended in all rock units. Besides pyrite, chalcopyrite, chalcocite, galena, sphalerite, hematite, and magnetite are also present. Covellite, digenite, and goethite are supergene minerals. Ore minerals have formed in crystal, vitric tuff and rhyolite as veinlet, dissemination, strata-bound dissemination, and inside silicic veins/veinlets. Three types of primary fluid inclusions are present within quartz minerals of silicic veins/veinlets and accompanied by disseminated ore minerals, including liquid-rich two phases, vapor-rich two-phases, and salt-saturated three-phase fluid inclusions (liquid, vapor, and halite + sylvite). Micro-thermometric analysis of these fluid inclusions shows the salinity of 1.05-14 wt% NaCl equivalents with the highest frequency of homogenization temperatures between 200 and 300 °C. The ore formation type is similar to intermediate sulfidation epithermal deposits, based on features like the vein-veinlet shape of ore mineralization, colloform and crustiform textures, base metal mineralization, the mineral assemblage of kaolinite – muscovite – pyrite ± sphalerite, intermediate salinity and temperature of the fluid, and probable effect of the boiling process.

Zardkooh procpect area is located in Sistan and Baluchestan Province in southeast of Iranshahr city. In terms of structural location, the study area is located on the boundary of Makran Arc Basin with the flysch zone of eastern Iran. The geology of the area is Upper Cretaceous volcano-sedimentary rocks, which is intruded by pyroxene diorite to monzodioritic units. The dioritic intrusion contains abundant quartz veinlets with a highly altered appearance. Mineralization in this area is mostly associated with silicification and argillic alterations with a large gossan zone surrounded by propylitic alteration. The primary minerals are pyrite and chalcopyrite and secondary minerals are goethite, hematite, limonite, jarosite, chalcocite, covellite, malachite and azurite, which seen as veinlet, disseminated, colloform, and replacement textures. The maximum amount of Au, Cu, Ag, As, and Zn elements are 1.1 ppm, 5%, 3.7 ppm, more than 100 ppm, and 759 ppm, respectively. Fluids inclusion study on quartz shows that the homogenization temperature is in the range of 188° to 365 °C and the salinity is between 14.5 to 18.2% eq. NaCl. Temperature and salinity data show the role of the mixing process of high temperature and salinity fluid (probable magmatic water) with meteoric low temperature and salinity fluid in the formation of mineral reserves. The type of alterations and their development, geochemical anomalies, temperature and salinity range, geological position, lithology, and mineralogy indicate that the mineralization of Zardkooh prospect area can be the upper part of a porphyry copper-gold type system.

The Zagros orogeny occurred with the opening of Neotethys, subduction and closure of ocean between Arabian and central Iranian microplate. The Sanandaj-Sirjan Zone is a metamorphic–magmatic belt, associated with the Zagros Orogeny as parts of the Alpine. The dominant plutonic rocks in the Sanandaj-Sirjan zone are considered to be a response to the subduction of the Neotethys. This paper discusses the mineral chemistry of amphibole and feldspar in the appinitic and granitic rocks which are exposed in SW of Nagadeh area. The appinite rocks consist of a group of coeval plutonic rocks, ranging from ultramafic to felsic in composition in which hornblende and feldspar are the dominant minerals, and typically occurs both as large prismatic phenocrysts and in the finer grained matrix. The composition of minerals in the appinitic and granitic rocks are similar,  and the composition of amphibole is magnesiohornblende and feldspars is orthoclase. Both magmas have calc alkalic characteristics with arc continental tectonic setting. They have derived from the crustal-mantle mixed sources and high magmatic oxygen fugacity. The appinitic rocks and granites have not coeval. Thermobarometric estimates using amphibole data show that the appinitic-granitic magmas crystallized in two storage zones at pressures of 3-5 kbar (shallow crust) and 1-3 kbar (upper crust). The appinitic rocks were derived from partial melting of lithospheric mantle that had been metasomatized by slab-derived fluids, in the shallow crust during Neo-Tethyan slab breakoff. Generally, it is difficult for the hydrous basaltic magmas to ascend through the continental crust, therefore the underplating of the crust by these magmas supplied sufficient heat and water to facilitate the partial melting of the overlying crust to produce the granites associated with the appinite.

Massive of dacite and trachydacite are present around the Masahim volcanic of Shahr-e-Babak are, in Central Iran, Urumieh-Dokhtar volcano plutonic belt. Based on lithogical studies and the results of chemical analyses, they are composed of dacite and trachydacite and the main texture in these rocks are porphyry. Both contain plagioclase (albite to andesine), pyroxene (augite), mica (biotite), amphibol (tschermakite), quartz and opaque minerals, but k-feldespar is also present in the trachydacite rocks (sanidin, anorthoclase). Phenocrysts of plagioclase show disequilibrium textures such as oscillatory zoning and sieve. These minerals show variations in composition from the core to rim that may be resulted from changes in magma composition with pressure changes during the ascent of magma and variation in water pressure. The temperature obtained is about 650 to 750 °C. Mineral chemistry studies on clinopyroxenes show that they are Augite and the magma, where clinopyroxens were crystallized, contained about 10% H2O. Fe3+ values of the clinopyroxenes indicate high oxygen fugacity. Geothermal-barometric studies of clinopyroxenes show that the crystallization pressure of clinopyroxenes is about 6-10 kbar and the composition of clinopyroxenes shows temperature range of 1200-1150 ° C. These clinopyroxenes belong to the calc-alkaline orogenic series.

In this study, MNPs-Fe3O4 were synthesized, and the properties of these nanoparticles were investigated by FESEM, XRD, FT-IR and VSM. In addition, the performance of MNPs-Fe3O4 along with ethoxylated tallow amine (TAE) surfactant in crude oil demulsification was evaluated by bottle test. The combination of MNPs-Fe3O4 and TAE improves the efficiency of water separation from oil by 94% and reduces the consumption of commercial demulsifier.

In this study, the effect of surfactant on the structural and photocatalytic properties of bismuth ferrite made (BiFeO3) by hydrothermal method at a temperature of 180 °C and a concentration of 4 M was investigated. The surfactants studied in this paper are ethylene glycol and sodium dodecyl sulfate. The results of diffraction pattern analysis showed that the samples have a rhombic perovskite structure distorted with space group R3c. Also, high purity bismuth ferrite was made at 180 °C and 4M concentration without the presence of surfactant. FESEM results showed that the particle size decreased with the presence of surfactant. The optical and photocatalytic properties of the samples were also investigated by UV-Visible analysis. The results showed that the amount of optical gap increased in the presence of surfactant and was recorded in the range of 2.7-2.8 eV for these samples. The photocatalytic properties of the samples were also investigated in Congo red at a concentration of 10 ppm. The results showed that ferrite bismuth made in the presence of sodium dodecyl sulfate had the most damage.

The aim of this study was to fabricate nanocomposites of titanium dioxide nanorods/gadolinium oxide and to investigate some of their properties. So, in this research, titanium dioxide (TiO2) nanorods were fabricated by microwave methods. The properties of crystal structure, morphology, optical, hydrophilicity and hydrophobicity of the samples were investigated. Nanocomposites of  5, 10, 15 and 20 percent of gadolinium oxide (Gd2O3) were fabricated using titanium dioxide nanorods. The properties of the fabricated samples, such as crystal structure and morphology, were investigated by X-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy, respectively. The results of experiments showed that titanium dioxide nanorod have a rutile phase with tetragonal crystal structure. The contact angle and visible-ultraviolet spectroscopy of the samples were also studied. Layer samples were made from titanium dioxide nanorods, gadolinium oxide (Gd2O3) and also various nanocomposites by spin coating method. The contact angle of titanium dioxide nanorods was about 44 degrees, indicating the hydrophilicity of titanium dioxide nanorods. Also, the results showed that nanocomposites samples with TiO2 nanorods reduce the hydrophilicity. The optical gap of titanium dioxide nanorods was about 2.9 eV. The optical energy gap of nanocomposite samples with different percentages of gadolinium oxide was almost constant.