مجله بلور شناسی و کانی شناسی ایران
سال بیست و پنجم شماره 2 (پیاپی 68، تابستان 1396)

The study area forms part of the Zagros Zone. It is located on the NW of Piranshahr town, NW Iran. The study of altered peridotite clasts of the Creteceous conglomerate is the main subject of this research. They have polygenetic origins having calcite as the constituent cement. The size of clast is ranging from mm to cm including sedimentary and metamorphic rocks fragments, altered peridotites and basaltic fragments. The peridotite clasts have been altered and carbonitized intensely. On the basis of spinel compositions, origin of the altered peridotite clasts are determined as the Alpine type ophiolite, comparable with the associated serpentinized peridotites of the Piranshahr ophiolitic complex. Presence of rare red-brown spinels as well as talc and serpentine support peridotites as the protolith composition of the intensive altered clasts. Calcite is the main secondary phase in the altered peridotite clasts of the conglomerates from the Piranshahr ophiolitic complex. Calcite in association with quartz and/or itself completely replaced magnesian silicate hydrous phases (serpentine) of the altered peridotite clasts. The secondary garnet having composition as andradite and grossular occurs as scattered grains in the clasts. Alteration processes of the peridotite clasts and formations of the secondary quartz and Ca2, CO32- rich mineral phases related to MgO-CaO-CO2 metasomatic fluid phases in the study area have been discussed in this research. Occurrence of the secondary quartz as well as high modal amounts of calcite in the altered peridotite calsts are evidence of carbonization and Ca metasomatism. The depositional basin can be probably supposed as appropriate and sufficient source of CO2 reservation which has been caused intensive carbonatization of previously serpentinized peridotite clasts with high carbonate formations. So it can be concluded that carbonitization of the formerly serpentinized peridotite clasts have been occurred after obduction of ophiolitic rocks and subsequent weathering and transportation of the serpentinized peridotites and conglomerate formation into the Piranshahr Cretaceous basin.

The Jebale-Barez plutonic complex (JBPC) is composed of granitic rocks and located in the E-NE of Jiroft in the SE part of Kerman Province. It is mainly consists of granodiorite but alkali-feldspar granite, granite, quartz-syenite and quartz-diorite can be observed in the region. The U-Th ratio in granitoids was used for petrogenetic studies. In this point of view, the JBPC has U-Th ratio lower than 5 which may imply its magmatic origin. The zircon isotopic closure of 900 °C and U-Pb ratio indicated that the U-Pb age (15.48±0.71 Ma) could be assigned to the crystallization of granitic magma. Some analyzed zircon crystals display inherited ages of Iranian basement (Early and Middle Proterozoic) which is not exposed in the study area.

Study area is located in Kerman Province and NE Baft city near to Rabor town. This section is in the structural division of Iran classified as Urumieh-Dokhtar magmatic belt which in Kerman area is called- Dahaj-Sarduieh belt that extended parallel to Urumieh-Dokhtar magmatic belt. These rocks comprise of andesite, andesite-basalt, dacite and rarely basalt and trachy-andesite with Eocene age that are associated with ignimbrite and pyroclastic flows. Studied volcanic units and intermediate dikes are covered by sedimentary sequences with N-S and E-W trend .Major minerals in these dikes are plagioclase (as major phenocryst) hornblende and Cpx and common minor minerals are biotite, quartz and opaque. Dominant texture in these rocks is porphyry, however many evidence such as corrosion of plagioclase, serisitization and disequbirilium texture observed. Based on major and minor element geochemical data, these rocks belong to calc-alkaline series and have metalumine trend. According to isotopic analysis and isochrones diagram, age of 45.7 Ma is obtained for study rocks. Based on these diagrams, 86Sr/86Sr ratio for these units is varied between 0.704759 to 0.705561 and value of 144 Nd/ 143 Nd is between 0.512711 – 0.512823 and εNd rangs from 1.68 to 3.82. This data shows a depleted mantle origin for dikes parent magma. Also variation of isotopic ratio in study units in NE Baft revealed an obvious upper crust assimilation which is associated with fractionation crystallization in an open system. Negative Eu anomaly and LREE enrichment more than HREEs and high value of LIL element relate to HFSEs bearing with negative anomaly of Ti, Nb and P demonstrate a subduction of Arabian oceanic crust beneath the Central Iran plate in active continental margin as a major tectonic setting for genesis of study area rocks. According to geochemical and isotopic analysis, these volcanic rocks probably formed from partial melting of mantle wedge that was associated with fluid and sediment derived from oceanic subducting crust that enriched from REEs.

Surface soils of Sabzevar zone could be geochemically divided into two groups of serpentine (Se) and non-serpentine (Nse) soils. Serpentine soils have higher MgO, FeOt, CaO, S, Ag, Co, Cr, Cu and Ni and lower SiO2, Al2O3, Na2O, K2O, Be, Li, Sc, Ti, U and V than Nse. In other word, Nse samples have high REE content with fractionated LREE/HREE trends in REE diagrams (ΣREE= 31.89- 58.3 ppm; LaN/YbN = 4.36- 5.68); while REE content of Se soils is lower and REE trends show LREE depletion (ΣREE = 12.29- 18.68 ppm; LaN/YbN= 0.69- 0.77). All studied soil samples have higher Ni, Cr and Co concentrations than environmental standard limitations. Heavy metal extraction by DTPA method shows that Se soils have higher bioavailability relative to other soils. Heavy metal analyses of alfalfa plants cultivated in different soils approves higher bioconcentration of these metals in Se soil samples. All studied soils display similar physico- chemical properties (pH, TOC and CEC) and mineralogical differences are the main factors controlling heavy metal bioavailability of Sabzevar soils. The existence of resistant oxide minerals in NSe soils inhibits the release of heavy metals and reduce bioavailable concentration of these elements; while structurally more open minerals like serpentine and talc led to higher availability of heavy metals in Se soils.

Garnet amphibolite is a member of the Hamedan regional metamorphic rocks (the Sanandaj-Sirjan zone). The present study is the first report of mineral compositions and P-T condition of the Hamedan region area garnet amphibolites. The garnet amphibolites can be divided into two varieties based on their mineral assemblages including epidote garnet amphibolite and biotite garnet amphibolite. Electron microprobe analysis show that they contain magnesio- hornblende, andesine and syderophyllite biotite and their garnets have chemical zoning with almandine and pyrope increasing towards the rims. Thermobarometry studies indicate that these rocks have been metamorphosed to lower to middle-amphibolite facies but the biotite bearing samples endured higher metamorphism degree that is consistent with their mineral assemblages. Although, regarding the relatively small differences between the estimated pressures and temperatures, different chemical composition of their parent rocks should be considered as a factor for determination of their final mineral assemblages. Whole rock analysis together with the mineral assemblages show that the garnet amphibolites are of para-amphibolite type and high K2O contents of the biotite bearing ones is the most important difference between these rocks which can be attributed to high impurities of the parent rocks. Overall, the thermobarometry results are consistent with high T-low P metamorphism (andalusite-sillimanite series) that is characteristic for the Sanandaj-Sirjan zone.

The Lakhshak pluton, a part of Zahedan-Saravan granitoid belt, is located about 15 km NW of the Zahedan city. The plutonic rocks are granodiorite in composition and are cut by a numerous of microdiorite and dacite dykes. The rocks of Lakhshak pluton consist of plagioclase (oligoclase-andesine), K-feldspar, quartz, biotite, amphibole (pargasite - edenite), sphene, apatite and opaque minerals. In this research, the composition of these minerals have been considered as the geo-thermometer and geo-barometer, hence they have good potential for calculating crystallization and emplacement conditions of a magma and tectonic setting. The presence of calcic amphiboles and primary biotite are evidence of Lakhshak pluton igneous origin (I). The amount of Altot in the pluton amphiboles are 1.02 to 1.32 representing the pluton emplacement at the depth of 3.8 to 8.4Km; while the core of those amphiboles analyzed from dikes contain Altot = 1.9-2.3 showing the depth of magma chamber in middle-lower crust (16.9-23 Km) as these dykes are thin and cooled fast after emplacment. The thermometry done on Lakhshak pluton and its dykes indicated cessation of exchange and equilibrium of minerals temperatures 645-732ºC for pluton, 730-824ºC for dacite dikes and for andesitic dikes are 808-945ºC. Moreover, biotites were plot in calc-alkaline field of Abdul Rahmans diagram, which represents the Lakhshak pluton might be formed in an active continental margin during the subduction of Sistan oceanic lithosphere beneath Afghan Block.

Kariro Pb prospect area, which is located in northwest of Boshruyeh, occurs as vein-veinlets, open space filling, and cement of fault breccia in Middle Jurassic metamorphosed shale (slate) unit of Baghamshah Formation. Mineralization zones contain dolomite (70-85%) and galena (0.5-2.5%) with small amounts of pyrite, quartz, and calcite. Dolomitization and silicification of host rock are the most important alteration prosesses in Kaviro area. Microthermometric measurement in two phase (liquid and vapour) fluids show that dolomite, quartz and ores are originated from a fluid with medium temperture (168°C to 250°C) and medium to low salinity (5 to 12.5 wt. %NaCl equivalent). From the comparison of Kaviro area with other Lut block vein-type deposits, and based on the dolomitization of host rock, without having relationship with igneous activity, open space filling texture, mineralogy, and flaid incusion considerations, the mineralization is probably of epithermal type.

In Iran, a large extent of the soils and water are facing with salinity; so the geotechnical properties of arid and saline soils are important for engineering design. In this study, the effects of salinity on geotechnical properties of fine-grained and coarse-grained soils containing fibrous clay minerals have been studied. The results showed that salinity was mostly a flocculated agent in fine-grained soils while in coarse-grained soils, it is usually a dispersing factor. In general, salinity increased dry strength parameters and decreased the optimum moisture content. But changes according to the type of clay mineral and particle size, distribution were different.

Intrusion of tonalitic, granodioritic and quartz-dioritic igneous bodies of Oligocene age into Cretaceous andesite, andesi-basalt and carbonate rocks led to occurrence of widespread argillic alteration zone, along with skarnification in the northeast of Kharvana (East Azarbaidjan Province, NW Iran). Mineralogical studies indicate that argillic alteration zone includes kaolinite, quartz, alunite, pyrophyllite, rutile, chlorite, jarosite, hematite, goethite and pyrite minerals. Geochemical investigations revealed that factors such as low pH, high water/rock ratios, abundant complexing agents in the hydrothermal solutions, and suitable drainage system have played an important role in leaching of elements such as Ga, Sc, Hf, Nb, Th, Ta, Zr, Y and REEs during the development of this zone. The distribution pattern of REEs normalized to chondrite shows differentiation and enrichment of LREEs relative to HREEs and occurrence of negative Eu and Ce anomalies during argillization of andesites. Variations of Eu and Ce anomalies suggest destruction of plagioclase, potassium feldspar and hornblende by hypogene solutions and generation of H2SO4 originated from oxidation of pyrite by supergene solutions in development of this alteration system. The correlation coefficients between elements display the controlling role of Mn-oxides in concentration of Cu, Pb, Zn, Cd and Tl. Concentration of REEs was controlled by adsorption processes (kaolinite), scavenging by metallic oxides and hydroxides (hematite and goethite) and fixation in neomorphic pahses (rutile, jarosite and muscovite-illite) in this zone.

Textural and Geochemical characteristics of plagioclase phenocrysts in Andesitic and basaltic rocks of Bazman volcano (from Makran volcanic arc) show evidence of interaction between basaltic and andesitic magmas. Plagioclase phenocrysts in andesites and basalts are composed of three major parts of core, mantle and rim, with similarity of the anorthite contents in cores and mantles. The cores of the phenocrysts, which seem to be in equilibrium with the andesitic magma rather than the basaltic one (­An39-60), exhibit different styles of oscillatory zoning. The trace element (Fe, Mg, Sr, Ba) concentrations in different zones of the cores also remain constant or change proportional to the anorthite content and may exhibit dynamic processes in the magma reservoir during the core formation in andesitic magma. The engulfed cores and sieve texture in the mantles of plagioclases may have formed in response to changes in temperature and composition of the surrounding melt. Elevated anorthite content of plagioclases (An40-65), accompanied by jump of the Fe, and Mg content, in addition to change in the patterns of Sr, and Ba in the sieve-textured mantle may show the replenishment of magma reservoir by new basaltic magma. Increase of An in the rim of basaltic plagioclases (from An53 to An74) and decrease of An in the rims of andesitic plagioclases (from An69 to An53), indicate that the two magmas gained their contrasting compositional identity most probably as a result of sudden upward movement. These constraints, along with other evidence like weakly-zoned pyroxene microphenocrysts with rounded rims, suggest that the rocks originated in the course of replenishment of mafic melts either with chemical or/and thermal interaction of the melts.

Crystal form of almandine-rich garnets from staurolite schists of Aliabad-Damagh, changes from pure {110} to pure {211} and intermediate forms between these two end-members. Compositional zoning patterns of all forms are similar, consistent with one-step growth during prograde metamorphism. Mineral chemical data indicate that (Mn Mg)/Ca in the ~60-micron rim of the almandine-rich garnet crystals were affected during this process. The ratio is about 8 for {110} and less than 2 for {211} forms. Changes in garnet-forming reactions from net-transfer to exchange reactions during prograde metamorphism, and consequently, changes in cation diffusion rates in the final stage of garnet growth affect crystal forms, since 110 and 211 faces have different growth rates.

The Bazman intrusive rocks are located in northwest of Iranshahr, south of Lut block, and above of Makran subduction zone. The Bazman intrusive rocks are composed of gabbro, diorite, monzodiorite, qurtze monzodiorite, granodiorite and granite. The Composition of clinopyroxenes is in the diopside-augite range and orthopyroxenes are enstatite. The studied amphiboles are classified as calcic (magnesio-hornblende) which point to the I type nature of Bazman intrusive rocks. Composition of plagioclase ranges from An0.98 to An57.5. Micas are Mg-rich biotite and show calc-alkaline characteristic (I-type). Based on mineral chemistry, the intrusive rocks show calc-alkaline characteristic (I-type) that correspond with tectono-magmatic characteristics related to subduction environments.

Estaj manganese deposit is located close to the Estaj village, 40 km southwest of Sabzevar, in Central Iran and Sabzevar subzone. Based on field evidences and microscopic studies, the rock units of the study area are pyroxene hornblende tracy Andesite, crystalin andesitic tuff, pyroxen hornblende andesite, pyroxen andesite- basalt, chert and limstone. These rock units belong to Late Cretaceous and can be one of the geological evidences for the origin of volcano – sedimentary mineralization. Chemical and mineralogical analysis by XRF, ICP, XRD methods and microscopic studies were performed over Estaj manganese ores. The result of XRD analysis confirmed pyrolusite as the main Mn oxide but psilomelane was distinguished only by microscope. The Chemical analyses of Mn ore indicated the high values of Si (17.01 – 75.54 ppm), Ba (300 – 1965 ppm), Sr (200 – 844 ppm) and MnO/Fe2O3 (1.62 – 58.61) and low amounts of Zn (34 – 79 ppm), Co (2 – 16 ppm), Ni (2 – 10 ppm), U (20 – 71 ppm) and Th (2 – 5 ppm). The result of geochemical analysis is indicative of deposition of manganease solution along with silica due to physio -chemical changes of sea water and also reflects the submarine hydrothermal origin for this mineralization. Ore bodies form layer and lense within the pyroclastic rocks (andesitic green crystalline tuff and red tuff) and can be seen as strat form with host rocks. Also ore bodies form amygdaloidal with pyroxene andesite-basalt. The ore bodies has massive, dendritic, layer and spherulitic textures and the mineralogy is mainly pyrolusite, braunite and psilomelane. Wall rock alteration in foot wall cansists mainly of chloritic, argillic and silicification. Estaj mineralization according to it's various characters such as volcano-sedimentary nature of the host sequence and the host rocks geometry, texture and structure and mineralogy, shows the most similarities to the volcano-sedimentary (exhalative –type) manganese deposits.

In this paper, β-PbO nanoparticles were prepared by microwave irradiation. Then, the PbO nanoparticles with size of 32 nm were doped in the Bi2-xPbxSr2Ca2Cu4Oy superconductor with x = 0.0, 0.2, 0.4 and 0.6. The samples were synthesized by the standard solid state reaction method. The structural properties, microstructure and morphology of the samples have been studied by XRD and SEM. After synthesizing the samples and observing the Meissner effect, the study of the critical current density (Jc), critical temperature (Tc) and thermogravimetry-differential thermal analysis shows that samples have been down. The results of the critical current density measurements show that the sample with x = 0.4 and an annealing time 60 h has the maximum Jc. Substitution of PbO nanoparticles for Bi reveal that remarkable increases in the critical temperature. The volume of the unit cell of doped samples were increased with respect to that of the undoped samples, which is shown Bi substituted by Pb.

Praseodymium ion (Pr3) substituted yttrium iron garnet nanoparticles PrxY3-xFe5O12 (x = 0.0, 0.1, 0.2, 0.3, 0.4) were fabricated by the sol-gel method. X-ray diffraction (XRD) patterns confirmed the pure garnet structure for all samples. The chemical bonds and the garnet phase were studied by using Far-FTIR. The magnetic hyperfine parameters were obtained by MÖssbauer spectroscopy and confirmed the VSM results. The results of vibrating sample magnetometer (VSM) represents that saturation magnetization increases with increasing praseodymium ion concentration for the samples with x = 0.0 to x = 0.2 and then decreases up to x = 0.4. These changes assigned to the Neel theory, Pr3 substituted at c site and the spin canting due to the sublattice splitting.

In this work, KTiOPO4 nanoparticles were synthesized by both hydrothermal and coprecipitation methods and studies were carried out on their structural and optical properties. To study the physical properties of samples, XRD, FT-IR, UV-Vis and FE-SEM analyses were used. Hydrothermal method, using different starting materials, resulted to the production of finner particles (9.6 nm and 12.54 nm) compared with nanoparticles (34.65 nm) produced by coprecipitation method.

In this research, Ce0.8Zr0.2-xMnxO2 nano particles (x = 0.0, 0.05, 0.10) were synthesized at 600AWT IMAGE calcination temperature by co-precipitation method. The starting materials were cerium and zirconium nitrates, manganese chloride and ammonia as a precipitating agent. The crystalline structure of the synthesized samples was studied by X-ray diffraction (XRD) technique. TEM images of the prepared Ce0.8Zr0.2O2­ and Ce0.8Zr0.1Mn0.1O2 showed that their average particle size are about 8.2 and 7.3 nm, respectively. Fourier transform infrared (FTIR) spectroscopy was used to investigate the present bonds in the synthesized samples.

In this paper, the chromium doped spinel zinc ferrite nanoparticles were synthesized by using of glycine as a fuel with microwave combustion method. After preparing the samples AWT IMAGE with x = 0.0, 0.5, 1.0, 1.5, 2.0, the electromagnetic and electrical properties such as dielectric constant, ac conductivity, dielectric loss factor (AWT IMAGEand Curie temperature were investigated. According to the results, increasing of the amount of chromium in samples causes to increase the real and imaginary part of dielectric constant. Although the chromium ions do not participate in transporting electrons between Fe and Fe, they cause reduction in transporting electrons. For a typical sample, the imaginary and real parts of dielectric constant and dielectric losses decrease and ac conductivity increases with increasing frequency, which is natural feature of ferrites. These results are described by Maxwell-Wagner model and Koops's theory. Also, the results show that the Curie temperature of samples increased a chromium added.