Iranian Journal of Crystallography and Mineralogy
Year:2013 | Volume:20 | Issue:4|Papers Count:13

In this research, the effects of cooling rate and high energy electron beam irradiation on the change of crystallinity of polypropylene was investigated. For this work, samples of polypropylene heated to 230 ºC and then rapidly cooled with different speed of cooling.Crystalliny of samples were determined by differential scanning calorimetry and infrared spectroscopy. It was shown that percentage of crystallinity depends on the cooling rate; therefore in higher cooling rate will be less crystallinity. Effect of electron beam on the samples that cooled in air by applying different radiation doses in 5-40 kGy was investigated. Gel content of each sample that shows the amount of chain crosslink between the transverse area Amorphous by using Xylene and percentage of crystallinity determined by using of DSC, FTIR and XRD spectra. The effect of radiation dose on crystallinity of samples revealed that the amount of crystallinity increases by increasing dose to about 30 kGy then decreases with increasing radiation dose.

The widespread stratigraphic sequences, from Precambrian to Cenozoic have been affected by metasomatic and thermal- metamorphic events of the Pliocene age by the Alam- Kuh alkali-granitic intrusion. Skarnification is the main metasomatic type in the studied area with 1-2km in extent. This intruded alkali-granite is probably related to syn-collision and post collision tectonic regimes as A-type granite. Intrusion of alkali-granitic rocks into the surrounded wall rocks caused to form the skarn zones and oxide-sulfide mineralization, mainly consists of magnetite and some chalcopyrite as well as pyrite. The fluid inclusion studies show five types of inclusions in quartz synchronous with mineralization as V+L+S, V+L, L+V, L, and V. Geothermometric evidences indicate temperatures of 478oC- 488oC and 368oC- 378oC for oxide phase formation and sulfide mineralization respectively. Magmatic and meteoric fluids mixing are effective in generation of fluids during mineralization processes. The field geology evidences, microscopic and geothermometery characteristics suggest a skarn origin for the metallic mineralization of the Alam- Kuh intrusive body.

The study area is located northwest of Iran (38 km SW of Qorveh); which is a part of Sanandaj-Sirjan Zone. The lithology of this pegmatite complex varies from pegmatitic syenogranite to granodiorite, which were intruded in the dolomitic marbels of the area. Field observation, thin sections studies, XRD, XRF and ICP analyses on minerals and rocks in the area show that the composition of these pegmatites vary from the rim to the center. In the center of the pegmatitic dyke, the grains are coarser and concentrations of quartz and feldspar increase, while the mica decreases. The geochemical study on the minerals indicate high amount of Ta (92-93.5 ppm), Tl (9 ppm), Ti (5275 ppm), Zn (668-724 ppm), Ag (29-33 ppm) and Nb (1620- 1710 ppm) in biotites and Ga (212-214 ppm), W (33-40 ppm) and Sn (85-87 ppm) in muscovites. Also garnets which exist in pegmatites are almandine-spessartine enriched in Y (1120-1150 ppm) and the amount of HREE/LREE elements in these garnets is high. In the analyzed beryls the amount of Ni (15-17 ppm), V (9-12 ppm), Cu (22-29 ppm) and Cs (108-123 ppm) elements is high.

The Paleogene volcanic rocks of Damash have a considerable outcrops in Alborz structural zone in Guilan Province. These volcanic rocks show a compositional range from olivine basalt, basaltic andesite, pyroxene andesite to andesite. The petrographical and geochemical studies indicate that the fractional crystallization of clinopyroxene and olivine play an important role in lithological varieties of the Damash volcanic rocks. The positive correlation of Hf and Nb v.s Zr, CaO/Al2O3 v.s MgO and Al2O3/CaO v.s SiO2 are geochemical signatures of differentiation of clinopyroxene and olivine. The depletion in elements such as Nb, Ta, Zr, Hf, P, Ti and high ratios of Ba/Nb, La/Nb and Rb/Y, and low ratios of Zr/Nb and Y/Nb are geochemical evidences of crustal contamination of these volcanic rocks.The range of the incompatible elements and comparison with the crustal data range show that these volcanic rocks have a clear elemental equilibrium with continental crust and have been contaminated with it.

The study area is located about 30km northwest of Kashmar, southwest of Keriz village and east of Siah Kuh mine. Based on field and mineralogical studies, the rocks are mainly polutonic, sub-volcanic and volcanic, aged Eocene. The carbonate unit, with Permian age, is exposed extensivelly in the area. The mineralization in the area appears as veins, lenses, massive and dissiminated forms. Vein and lens type mineralization are related to the fault zones.The main mineralization in the area is magnetite, which occurs mostly as veins, lenses and massive. Dissiminated forms are less abundant. Other mineral veins and lenses in the area are specularite, chalcopyrite, pyrite, hematite, malachite, quartz and carbonate. Weathering of hypogen sulfide minerals has generated huge surficial amounts of secondry minerals such of malachite. Tectonically, there are three types of fault in the area: normal, strike slip and thrust, trending mainly northwest-southeast. The vein mineralization- trend is the same as fault- trend.The strike slip faults have been responsible mostly in providing suitable spaces for the uplift and porefluid filling. The magnetite has formed hydrothermally in contact with limestone and intrusive bodies. The existence of copper positive anomalies, I type granitoides, as well as fault mineralization may be considered as an evidence to prove that the iron oxide deposit in the area is a member of Fe-oxide type.

Nano technology makes the possibility to achieve specific properties for materials. In this process, by reducing the size of materials in the range of nano size, new noticeable behaviour for material can be observed. Such behaviour cannot be observed for larger particles from that material. Bentonite soils contain more than 76% montmorillonite and some other minerals. Pure montmorillonite with nano size has a vast industrial application in which its production is relatively costly and time consuming. This research is aimed to propose a method for segregation of bentonite components to reach nano montmorillonite. To achieve this objective, a mechanical method is proposed. Based on this method, a nano montmorillonite with micro and nano size is achieved. The segregation process is monitored with PSA, XRD, SSA and SEM experiments. The results of this research show that a nano montmorillonite with SSA of 522.58 m2/g and average diameter of 6.13 micron is attained. The achieved nano montmorillonite has larger purity in comparison to Cloisite Na+. In addition, it has lower average particle size than Cloisite Na+. Furthermore, according to the results of this research the extracted nano clay is free from carbonate and quartz particles. The SSA of this nano montmorillonite was 25% more than that of bentonite. The proposed method is relatively inexpensive. Moreover, since no chemical is used in its production process, it is a suitable sample for practical, research, and industrial projects.

The mafic and ultramafic igneous rocks of the ophiolitic complex in eastern Birjand) between Sulabest in southern part to north of Gazik in northern part) Have been studied.According to plot of data on diagrams and the result of mineralogy and geochemistry, gabbros and some peridotites belong to cummulate series of spreading sea floor magma (MORB) where some peridotites are of metamorphic (tectonics) types. Magmatic series of igneous rocks are tholeiitic. Trace elemental patterns similarities on spider diagrams also confirming the relations of these rocks to Mg-rich basaltic magma of MORB type. Geothermobarometry results of some rocks, based on different calibrations, show temperatures of 944LC for gabbros to 1294LC for peridotites. Temperature pressure calculations based on Holland and Powell thermocalc method, indicate, rocks crystallization conditions of 748LC and 17.46 Kb for gabbros to 1282LC and 24.7 -33.6Kb for peridotites. Most obtained temperatures, particularly the thermocalc ones, for crystallization conditions of these rocks from an initial Mg-rich magma, MORB type, in spreading sea floor seems to be reasonable.

Triassic (mostly volcanic-carbonate) and Jurassic (mainly shale and sandstone) rocks in west of Malayer were affected by a number of shear zone, folding, deformation and metamorphic events. Regional metamorphism in the area led to the formation of Triassic and Jurassic rocks such as phyllite, slate and crystalline carbonate which folded during deformational events. In the contact metamorphism event, granitoid plutons with predominantly granodiorite to quartz-diorite composition intruded the metamorphic rocks, forming mineralized skarn zones in Anjireh, Iraneh and SarabSaman areas. The present research shows that plutons producing the mineralized skarn zones in the area are on average granodioritic in composition.Pyroxene and garnet minerals in the skarn zone comprise of diopside, augite and grandite (mainly andradite), respectively. In these skarns, various sub-zones are recognized and defined on the basis of their mineral paragenesis. High temperature facies (pyroxene-fels) formed in the temperature range of 650-800 oC and wollastonite up to 800 oC. However, hornblende-fels and albite-epidote-fels facies formed in the temperature ranges 500-650 and 350-500 oC, respectively.

Gazu prospect area is located about 65Km southeast of Tabas in the southern part of Shotori range. Sub-volcanic intermediate intrusive rocks (Upper Cretaceous?), monzonitic to dioritic in composition, intruded into carbonate rocks of Shotori Formation (Triassic) which are the main source for copper mineralization in Gazu district. Alteration zones associated within the intrusive are: Quartz- sericite±pyrite (main type), silicified- sericite, propylitic, silicifiedpropylitic and strong silicification. The carbonate unit is silicified, near some intrusive rocks, and in some area Skarns were formed. Mineralization occurs mainly as stockwork and disseminated with minor breccia. Veinlet’s type is: Quartz, pyrite, quartz- pyrite, quartzcarbonate- sulfide, carbonate-sulfide and sulfide. The density of quartz-sulfide veinlet with sulfide minerals is about 40 per m2, in some places. An extensive gossan zone is formed due to oxidation of sulfides appeared in intrusive rocks and carbonate unit that due to oxidation of sulfide minerals. The geochemistry of stream sediments are as follow: Cu=36-1200 (ppm), Pb=36-125 (ppm), Zn=62- 738 (ppm). Rock chip geochemistry is: Cu=100-20000 (ppm), Pb= 10-400 (ppm), Zn=50- 3000 (ppm). High content Cu and Zn are associated with quartzsericite±pyrite and strong silicification. The evidence shows that the Gazu is porphyry copper and related skarn type system.

Incheh granitoid intrusion is located east of Herris, East-Azerbaijan Province. It intruded into the older rock units including Eocene volcanic - volcaniclastics. Compositionally, this intrusion ranges from diorite-quartz diorite to monzonite. Chemical composition of its major minerals such as feldspars, amphibole and clinopyroxene analyzed using electron probe micro-analyzer (EPMA) for thermobarometeric study. The analyzed feldspars are mainly andesine to bytownite and sometimes albite. Clinopyroxenes are diopside to enstatite, and the composition of amphibole ranges from edenite, tremolite, tschermakitic hornblende, tschermakite to actinolite. Geobarometery of this intrusive, based on Al(t) in hornblende and Cpx-Pl-Qz barometers yields, 7±1 and 9-10 kb, respectively. Temperatures of 1000±40oC and 800-1000oC are estimated using the continuous reaction between plagioclase - amphibole, and two feldspar thermometers. Thermobarometery based on Al and Ti oxides in amphibole shows temperature of 900oC at pressures about 6-7 kb for amphibole crystallization in Incheh granitoid.

Paleosols of the study area is a part of the Eastern-Alborz Zone which is located about 50 km southeast of Azadshahr. These paleosols developed on floodplain and lacustrine facies of the Devonian Padeha Formation. Based on the field and textural evidences, two major paleosol horizons identified as A and B horizons. The A horizon consists of calcrete and noncalcrete paleosols which is located in the floodplain facies of the Padeha Formation. The B horizon identified in the lacustrine facies and consists of calcrete paleosols. Quartz, calcite, dolomite, microcline, hematite, albite, sericite, illite, chlorite and montmorilonite were identified in the paleosols. Geochemical analyses of the paleosols reveal the enrichment of immobile elements and depletion of mobile elements. Investigations of chemical alteration and effective chemical alteration indices indicate intermediate weathering in the study area. The occurrences of noncalcrete and calcrete paleosols suggest a climate change from humid to dryer condition occurred during soil formation. Combinations of textural, mineralogical and geochemical data indicate an origin of basic igneous rocks for the paleosols of the study area.

In this research, mesoprous compound MCM-41was synthesized by using CTAB as template and TEOS as silica source. In order to increase the adsorption capacity, the surface of the synthesized adsorbent was modified by 3-aminipropyletrimethoxysilane. The structure of the adsorbent was studied by XRD, IR, BET and TG-DTG techniques. For removal of cerium ion from aqueous solutions, NH2-MCM-41 adsorbent was employed. The effect of experimental conditions including pH, initial cation concentration, contact time and temperature were investigated. Maximal adsorption capacity was obtained at ph=6.

In this study, at first the magnetite (Fe3O4) nano particles were prepared by sol-gel method under inert atmosphere using ferric nitrate (Fe (NO3)3.9H2O) and ethylene glycol (C2H6O2) as precursors. In the next stage, magnetite nanoparticles were modified by Sodium citrate under Ar atmosphere. Also zinc oxaid (ZnO) nanoparticles were provided via coprecipitation route and heat treatment using ammonium carbonate and zinc acetate as precursors. The precursor was dried and then calcined at 350oC. Finally with the ZnO and modified Fe3O4 nanoparticles, core-shell system was produced. X-ray diffraction pattern (XRD) considered structure characteristic and the size of crystallites. Morphology and the average size of particles were determined by SEM and TEM electron microscope. The UV absorption spectra show that absorption wavelength value for Fe3O4/ZnO core-shell is increased in comparison with ZnO pure nanoparticles. FT-IR Spectra indicated the characteristic absorption of Zn-O bond is at 443/81 cm-1 and Fe-O bond is at 540/20 m-1. Variation of magnetization of samples with respect to the external field was investigated by Vibrating Sample Magnetometer (VSM).Investigation shows that Fe3O4 nanoparticles are super paramagnetic but Fe3O4/ZnO core-shell nanopowders are ferromagnetic. On the other hand, in core-shell system, the amount of remanence or coercivity field have not had a considerable changes with increasing in molar ratio of ZnO to magnetite.