Iranian Journal of Crystallography and Mineralogy
Year:2014 | Volume:22 | Issue:1|Papers Count:21

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South Kiki granitoid intrusion is located north of Semnan Province, about 5 km south of the village of Kiki. This pluton emplaced wholly within the Jurassic sandstones with typical contact metamorphic aureole around their periphery. The plutonic rocks suffered hightemperature deformation with well-developed S-C fabrics along shear zones marginal to the intrusion. The pluton was subjected to intensive plastic deformation in the contact so that the deformation gradually decreases with increasing distance from margins toward the inner side of the pluton. Due to high-temperature deformation, some of primary magmatic minerals such as plagioclase and orthoclase were broken and were filled again by some high-temperature magmatic minerals such as biotite, potassium feldspar and quartz. Based on the following evidences, it seems that the deformation happened during the emplacement of the pluton Just above the solidus temperature and possibly in presence of a small amount of molten: 1) Filling fractures of primitive feldspar crystals by sets of fine grain quartz, potassium feldspar and biotite (Sub-magmatic structure), and also transforming of monoclinic orthoclase to microcline at high stress rates which led to formation of the orthoclase lenses.2) Presence of quartz and feldspar grains within the deformed cleavages of biotite and bending of the biotite cleavages to smaller chlorite assemblage at higher deformation.3) Quartz and potassium feldspar intergrowth partially replaced plagioclase and also kink band and submagmatic structure occur in the plagioclase crystals.4) Existence of the undeformed granophyric textures in the margin of deformed orthoclase crystals.5) Individual crystals of quartz normally show undulose extinction and recrystallization.

The mercury (II) complex, Hg (Meca2en) I2 (1), containing bidentate Schiff base ligand Meca2en= N, N (-bis [(E) -2-benzylidenepropylidene] ethane-1, 2-diamine, has been synthesized and characterized by elemental analyses (CHN) and 1H-NMR spectroscopy. The crystal structure of 1 was determined using single-crystal X-ray diffraction. Structural investigation shows that 1 crystallizes in a monoclinic system, with space group P21/n. The Schiff base ligand Meca2en acts as a bidentate ligand coordinating via two N atoms to mercury (II) ion.

In this work, the structural and magnetic properties of ingot and melt-spun Pr3Fe24.75Co2.75Ti1.5 compounds have been investigated. The structural characterization of the compounds, by X-ray powder diffraction, is evidenced for a monoclinic Nd3 (Fe, Ti) 29-type structure (A2/m space group). A 2-type FOMP have been observed in the magnetic AC susceptibility curves of the ingot and melt-spun compounds.Magnetostriction and linear thermal expansion measurements have been performed by the standard strain gauge method in magnetic fields up to 1.5 T, and temperature range of 77 to 575 K. The calculated values of the ordering temperature, the room temperature saturation magnetization for the melt-spun Pr3Fe24.75Co2.75Ti1.5 compound are several times smaller than the corresponding values obtained in ingot Pr3Fe24.75Co2.75Ti1.5 compound. The above obtained results have explained the behavior of measured values of spontaneous volume, longitudinal and transverse magnetostriction.

The Kuh-e-Sarhangi shear zone, with N70oE striking, is the northeastern part of the Kashmar-Kerman tectonic zone locating at the NW of the Lut Block. The Late Precambrian- Early Cambrian four granitic bodies have been intruded in the Kuh-e-Sarhangi shear zone. The Deh Zaman granite consists of two mezocrat and hololeucocratic bodies that are presenting strong ductile deformation and the mylonitic foliation wich is well developed. This strong mylonitic foliation displays steeply dipping to the NE (S62o E/80o,). The plunge of the kinkfold axis and rake of the stretching lineation on the mylonitic foliation is about 75o and 35o to E-SE, respectively. Micro-structural shear sense indicators including oblique foliation, asymmetric porphyroclast, mica fish and of shear bands that show sinistral sense of shear. Quartz and feldspar microstructures are studied in order to find out deformational conditions. Sub-grain rotation recrystallization (SGR) in quartz grains and brittle deformation to bulging (BLG) recrystallization in feldspar grains indicate 300oc-500oc temperature of deformation that is consistent with green schistto epidote amphibolite facies conditions. These evidences also confirm the delay of deformation with respect to the granite intrusion.

Zoisite and clinozoisite are coexistent in the Salmas epidote- amphibolites, NW Iran.The frequency of zoisite is higher than clinozoisite in the studied epidote- amphibolites. The pistacite content of zoisite is lower than clinozoisite. XPs in zoisite is about 6.46-10.65% while for clinozoisite it is about 16.72-18.73%. Al-Fe3+ substitution was effective to create the mineral compositional changes in the Salmas epidote group minerals. Composition of coexisting zoisite and clinozoisite is a function of pressure, temperature and whole rock composition. According to zoisite and clinozoisite phase relations and compositions, epidote- amphibolite metamorphism in the Salmas area occurred at temperature of 500±20 oC and pressure of 6.5-7 Kbar conditions.

The Cheheltan Mountain is located at south west of Bardsir, Kerman Province. It represents a part of the Eocene Hezar volcanic complex (Urumiyeh-Dokhtar volcanic belt) and consists of lava flows, pyroclastics, epiclastics and numerous intrusions. The lava flows comprise of basaltic-andesites and basalts and contain plagioclase and pyroxene phenocrysts that set in a vitreous or fine-grained matrix. Geochemical studies show that the lava flows belong to the calcalkaline and high-K calcalkaline magmatic series, and in the variation diagrams, they show continuous chemical trends, which can be formed due to fractional crystallization of minerals such as olivine. These rocks show negative anomalies of Nb, Ti, Ta, HFSE and HREE, and positive anomalies of Ba, Rb, Th, LREE and Sr in the spider diagrams, resembling the subduction related magmas. These evidences show that the parental magmas may have been affected by crustal contamination processes. According to the petrogenetic studies, these magmas belong to the active continental margin setting, and all of them have the same source. The present work shows that the parental magmas of the studied rocks, probably originated by partial melting of metasomatized mantle sources in a subduction zone environment.

In this study, brine and sediment samples from the Meighan basin located about 15 km northeast of Arak city were considered. Sediments samples were collected from boreholes and surface sediments of playa bed were studied for their mineralogical content by X-ray diffraction (XRD) technique and sedimentology. The results showed that the Playa sediments were consist of chemical (evaporate) and detrital (quartz, muscovite and clays) minerals.Evaporate minerals including calcite, gypsum, halite, glauberite, thernadite, polyhalite, natron and very small amounts of dolomite, magnesite, bassanite and sylvite are present. The study of surface sediments indicate that carbonate and sulfate minerals were precipitated along the margins of the playa whereas the minerals with higher solubility like halite appear in the central parts. In other words, a kind of mineralogical zonation which obeys the Bull's-eye pattern occurs in the Meighan playa. Study of geochemical evolution associate with minerals precipitation suggest that high concentration of Meyghan playa brines to formation of chloride and bitter salts and Na-Cl-SO4 brines.

The study area is located at northeast of Neyshabour in the Khorasan Razavi Province, northwest Arghash Gold Mine. The rocks of area are composed of polutonic to subvolcanic units with acid- intermediate in composition. They consist of granodiorite, diorite and granite. Alteration zones are: propylitic, sericitic, silicified and argillic. In the study area, mineralization is divided into two types: primary and secondary. The Primary mineralization consists of disseminated type in intrusive bodies (syngentic) and vein-type mineralization in fault zones (epygentic). Pyrite is recognized in dioritic and granitic intrusive as disseminated.The vein- type mineralization consists of chalcopyrite, pyrite, quartz and calcite minerals which are related to NE-SW, NW-SE, E-W fault zones dipping 60 degree. Secondary minerals in the study area are malachite, azurite, hematite, goethite and covellite. Geochemical study in the area shows anomalies for Cu, Pb and Zn in primery and secondary geochemistry halos. High concentration of Cu, Zn and Pb in stream sediments samples are 124, 85 and 38 ppm and in rock samples are 2200, 336 and 589 ppm respectively. Based on present of disseminated mineralization in the surface and undersurface Arghash area, present of vein-type mineralization Au and Sb in the arghash area and present of vein-type mineralization in the fault Zone in the study area, present of geochemistry halos for Cu, Zn, Pb in the study ares and surrounded, probably Arghash area can be vein-type mineralization ralatad to copper porphyry system in this area.

Zan lateritic horizon is located about 25 km southeast of Damavand, Tehran Province. This horizon developed as stratiform in lower part of shales and sandstones of Shemshak Formation (Jurassic). Mineralogical investigations show that diaspore, hematite, goethite, anatase, and kaolinite are the principal minerals of this horizon accompanied by lesser amounts of accessory minerals like boehmite, siderite, rutile, quartz, titanomagnetite, zircon and pyrite. The mineralogical composition of the ores indicates a semi-acidic to alkaline and reduced to semi-oxidized environment for the formation of this horizon. Chemistry of the major elements reveals that weak to moderate lateritization processes caused the formation of ores of bauxitic clay and ferruginous laterite, and laterite composition in this horizon. Correlation coefficients among elements suggest that anatase, rutile, zircon clay minerals, Mn-oxides, and secondary phosphates (xenotime and gorceixite) are the potential host minerals for REEs in the ores.

The chemical composition of biotites of granitoid rocks of NW Saveh plutons are characterized by lower interval in total Al contents and Fe/ (Fe+Mg) ratios which both features are very important to indicate the crystallization of host magmas. In the annite- sidrophylitephlogopite- eastonite (ASPE) quadrilateral used to plot the composition of trioctahedral micas based on the above parameters, all of the biotite samples from these plutons cluster together and show no trend that can imply absence of assimilation by crustal materials. Biotites from these plutons are primary and formed in high fugacity oxygen conditions and show calc-alkaline I-type properties. This is consistent with the suggested tectonomagmatic characteristics implying magmatic arc associated with subduction zones.

Bondono granite-gneiss body is located in the core of Toutak anticline, located 200 km NE of Shiraz. This granitoid mass, which is a part of Toutak metamorphic complex, is exposed on the Sourian sheet. Petrological studies determined that the mentioned rocks are placed in orthogneiss field. Based on current studies, the geochemical, tectonic setting and geochronology characteristics of the Bondono granitoid mass are similar to some of the granitoid masses of central Iran’s zone, such as Ariz, Boneh-shooroo, Zarigan and Dozakh- Darreh. All of these masses have calc-alkaline and per-aluminous behavior and have formed in active continental margins. According to the current geochronology studies, based on zircon UPb method, the Bondono granite-gneiss has an age of about 538.5 ma, which is close to the age of granitoid masses that are referred before. The determined age indicates that Bondono granitegneiss have formed during the Early Cambrian period which is comparable to the movements of Katangan orogeny.

Felsic volcanic rocks embrace a portion of the volcanic succession in Kajan area of Urumieh-Dokhtar magmatic assemblage. Based on trace elemental abundances and patterns, the felsic rocks might be attributed to two distinct series. In one series, normalized trace and REE patterns are rather flat (La/Yb<17) but display negative Ti, P, Sr and Eu anomalies. This series, which is called normal calc alkaline series, is comparable to the felsic melts evolved by differentiation of mantle-derived basic partial melts in subduction zones. In the second series, which is here called adakitic series, trace and REE patterns are steep (La/Yb>28) and positive Sr anomaly. Origin of the magmas that generated the latter series is likely to be the Neotethyan slab partial melts under high pressure (amphibole eclogite mineralogy).

The study area (Kalateh-No) is located in NW of Gonabad city in Khorasan Razavi Province. This area is located in geotectonic Lut Block zone. The rock types are mainly of volcanic and subvolcanics. The most important alteration zones are silisification, propylitic, argillic, serisitic and quartz-serisit-pyrite. The mineralizations have formed by intrusion of hydrothermal fluids of monzodiorite porphyry and alteration of rocks along its path. The mineralogical compositions are quartz, illite, muscovite, montmorillonite, albite, orthoclase, gypsum and iron phases (pyrite and hematite). The chemical composition shows the high percentage of SiO2 (average: 66.97%) and the amount of Alumina (Al2O3) is low (average: 17.67%). The meteoric water and hydrothermal fluids caused two types of supergene and hydrothermal clays, which supergene clays are deposited at the top clays hydrothermal clays.

The Middle Jurassic granitoids from Molataleb village lie in the Sanandaj-Sirjan zone. This body located, NW of Isfahan, and is predominately composed of tonalites and twomica peraluminous granodiorites cross cut Jurassi (Liass-Dogger) shales and slates. Tourmaline and garnet are among significant minor minerals of the granodiorites. Subhedral to anhedral tourmaline with pleochroic brown-green to blue color occurs as small amount among other minerals of these rocks. On the bases of chemical data as wall as geochemical diagrams, the studied tourmalines are characterized by weak chemical zoning, more Mg than Fe and deravite in composition. The content of other end members (schorlite, uvite, foitite) is insignificant. Mgtourmalines, are associated with metamorphic or metasomatic assemblages. The origin of these minerals is likely related to meta-sedimentary rocks (i.e. meta-pelites and meta-psammites) coexisting with a Al-saturated phase. The studied garnets are anhedral, rimmed and cross cut by veins contain small crystals of biotite and muscovite. In few cases, both biotite and muscovite are found in investigated garnets. Locally, garnets are surrounded by chlorite crystals.Chemically, the garnet is almandine with a rim relatively enriched in spessartine and fairly depleted in pyrope. The revers zoning is characteristic of high grade-metamorphic garnet and point to its crystallization in a low-pressure system. The high content of Mn in residual liquids derived from the crystallization of magma, caused the stability of garnet. On the bases of available data, the pelitic deposits (Lower Jurassic), have been subjected to progressive regional metamorphism (upper amphibolite-lower granulite) followed by partial melting of metapelites.The studied garnets (Fe-Mg phases) formed at or near the climax of metamorphism.

In this research CoxMn1-xFe2O4 nano particles (0£x£0.7), using high purity metal nitrates and citric acid have been prepared by sol gel auto combustion method. The obtained powders were characterized by XRD, FT-IR, SEM and VSM analysis. The XRD patterns showed that the formed crystallites were all in the cubic single phase and the formed crystallite belongs to the space group Fd3m and average particle size was 20 nm. It is observed that for x£0.5, ions Co2+ substituted into MnFe2O4 tends to increase the lattice parameter and for x=0.7, tends to reduce the lattice parameter. FT-IR spectra showed that the metal-oxide vibration band 570 cm-1 assigned the band to the tetrahedral group that corroborated the spinel structure.By the SEM micrographs of the Co-Mn ferrite samples studied, and it can be seen that particles of samples are spherical in shape with the average grain size varies between 50 nm and 80 nm. Hysteresis loops of the samples were obtained by Vibration Sample Magnetometer (VSM) demonstrated an initial increase in the saturation magnetization for x£0.5, then decreases for x=0.7 caused to the difference in the contributions from the magnetic moments of the substituted ions on tetrahedral sites and octahedral sites in the spinel ferrite.

Kahang porphyry copper deposit is located in Isfahan Province, in the middle of Urmia-Dokhtar Magmatic Belt. Based on field investigations and petrography of thin sections and core samples, igneous rocks in eastern part of the deposit are divided into three types of host-rocks, source and mineralizing rocks, and post-mineralizing barren dikes. Quartzdiorite has formed more than 70 percent of the main mineralizing stock. Geochemistry of volcanic and plutonic rocks shows that these rocks have formed from a single Calk-Alkaline magma that has produced various igneous rocks by differential crystallization. With increasing Si oxide, Na2O and K2O linearly increase, and FeO, MgO, CaO, P2O5, Al2O3 and TiO2 linearly decrease. Trace elements including Rb, Th, Ba and La, as well, with increasing SiO2, linearly increase, Sc, Yb, Ni and Y decrease, and Ce has a constant trend. The main alteration types in the deposit are Potassic, Phyllic, Quartz-Sericite, Propyllitic, and Argillic. Biotite is the major product of potassic alteration, and hydrothermal alkali feldspar could only be observed in depths greater than 730 meter. Fluid inclusion studies on mineralized quartz veins in Potassic zone confirm that Cl-bearing saline fluids have carried Cu, and porphyry mineralization has formed in a temperature, pressure and depth of about 415oC, 340 bars, and 1.3 km, respectively. Boiling and fluid cooling in A2 and B veins are the main controlling factors in precipitation of chalcopyrite in Kahang PCD.

Mohammadabad-Oryan index is the only borate index in the north-east of Iran that is embedded in the formationscontainingtuff marl, tuffaceous marl, volcanic breccia and tuff brecciawhichbelongs to cretaceous. This index is located about 50 km south of Sabzevar. Two NE-SW trending thrust and reverse faults have occurred in the area. These faults were pathways for ore forming solutions and created open spaces for ore deposition. Magnesium, magnesium-calcium, calciumhydrated borates and hydroboracite (Mg-Ca Borate) are the most important minerals of this index. The nodules of ulexite can be clearlyobserved in the area. In addition, tincalconiteand meyerhofferitehave also been detected by XRD.According to the field observations, this index is located in the rock units of clay, marl and tuff. Due to its similarity to other known borate deposits, it can be concluded thatborateminerals areprecipitatedin fractures aslens shaped orebodies, discordant with sedimentary clay-marl layers. Field observations on dug trenches in the area show that the mineralization intensity decreases with depth.It seems that meteorite waters penetrate to depth, through tectonic fractures, and go up after warming (due to the high geothermal gradient), creating some thermal convective circulating cells. The lower rock units are leached within cells and produced boron-rich fluids, then borate minerals deposited in fractures within clay-marl layers as result of reducing conditions.