مجله بلور شناسی و کانی شناسی ایران
سال بیست و دوم شماره 2 (پیاپی 56، تابستان 1393)

Keybarkuh area is located about 70 Km southeast of Khaf city in Khorassan Razavi Province. The study area, with 60 km2, is bounded to the east by Zouzan (Ghasemabad) and to the west by Keybarkuh. Rock units mapped in the area consist of sandstone, shale, limestone (Carboniferous to Paleocene); slate, mica schist (Paleozoic) and a complex of intrusive rock (Cretaceous to Tertiary) formed as dyke and stock. The composition of intrusive rocks varies between granite to diorite. Based on magnetic susceptibility, intrusive rocks are divided into ilmenite (reduced) and magnetite (oxidant) series. Propylitic alteration zones with broader extension and sericitic, argilic and silicic alteration with lesser extension are located in the southern section. Skarn zones were identified in some location. Pyrite, chalcopyrite, magnetite, galena and barite mineralization were identified in the south of the studaed area. Ground magnetic survey carried out to determine relative depth and extension of intrusive bodies related to mineralization. 526 stations with 25 and 50 m spacing in ten profiles with 600 to 700 m apart oriented northeast-southwest were surveyed. After correction and processing of magnetic data, TMI, RTP, 1VD, and Upward Continuation maps were produced. Using these maps, distribution and relative depth of the magetic source of A, B, C, D, E and F anomalies, which are intrusive bodies, were identified. Magnetic anomalies in the RTP map, which are related to intrusive bodies and alteration zones in the southern part of the area, have a circular to semicircular pattern arise from the presence or absence of magnetite in the intrusive bodies and alteration zones. Based on the mineralization evidences, alteration zones, intrusive rocks, and magnetic anomalies, the southern part of the area has potential for porphyry copper mineralization. Considering the presence of iron skarn and high magnitude of the magnetic anomaly D, the central part of the area has potential for magnetite skarn.

The nanostructured nickel oxide thin films were prepared by dip coating sol – gel method. Three methods (drying with oven, IR and microwave) have used for drying the films. The effect of drying method on the optical, molecular, electrical, structural, and morphology properties of the films were studied by Uv-Visible spectrophotometry, Fourier Transform Infrared spectroscopy, Hall effect, X-ray diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy. Optical constants of nickel oxide thin films were calculated by using Pointwise Unconstrained Minimization Approach. The optical band gap of the films dried by infrared, oven, and microwave methods obtained 3.62, 3.59, and 3.47eV, respectively. The X-ray diffraction patterns of samples show that the film dried by infrared is amorphous while by two other methods are crystalline.

In northern hillside of Central Alborz, south of the Kamarbon village, there is an outcrop of alkaline gabbro that has fine grain theralite in margins and toward the center, changes to coarse grain teschenite. In the teschenitic rocks the main minerals are diopside clinopyroxenes and rhonite. In this research, the occurrence of this mineral in Kamarbon gabbroic intrusion is reported and its mineralogical properties, paragenesis and source of magma are investigated based on whole rock and microprobe analysis data. In these rocks, rhonite has (Si, IVAl)6.02(Ti, VIAl, Fe+3, Fe+2, Mn, Mg)5.99 (Na, Ca)1.97O22 composition. This composition is similar to pervious published analysis of rhonite. Studied rhonites in teschenitic gabbroitic rocks has low values of Na+IVSi and high values of Ca+IVAl that can be primary source for this mineral. The studies indicate the stable paragenesis of rhonite and Al rich clinopyroxene. Considerable factors for crystallization of rhonites in undersaturated magmas are enrichment of Al and Ti and depletion of Si whereas associated clinopyroxenes represents enrichment of Al2O3 and TiO2 and depletion of silica. Therefore regarding to the mineralogical and chemical properties of rhonite and associated clinopyroxenes, it could be concluded that rhonite mineral may be produced from an undersaturated alkaline magma enriched in Al and Ti. Occurrence of rhonite and associated clinopyroxenes in south Kamarbon teschenitic alkaline gabbros represents the existence of an undersaturated plutonic phase in nothern part of Central Alborz.

The plutonic bodies in northeast of the Sonqor area is a small part of the Sanandaj-Sirjan zone. According to the field and microscopic observations, the study area is composed of two major units; massive rocks (hornblende gabbro, intermediate and felsic rocks) and dikes (pyroxene gabbro). Mineralogical and geochemical studies show that this granitoide compelex is I-type, calk-alkaline and metaluminous. The regular variation trends in the main and trace elements diagrams demonstrate that these massive rocks are generated by fractional crystallization process. The changes in ratios of Zr/Nb and La/Yb in these rocks indicate two different origin which are spinel lherzolite to garnet lherzolite (massive rocks) and spinel lherzolite (dikes). Also Th/Ta ratio in the range of (6-20) and enrichment in LILEs and LREE relative to HFSEs and HREE, all of these evidances indicate the intrusion of this body into the subduction zone which is related to an active continental margin setting.

The studied volcanic and pluton rocks are located in west of Nir city in the Ardebil Province and south of Sabalan volcano. Volcanic rocks in the studied area are display basaltic to trachy-andesite composition with microlitic porphyry texture. The main minerals of basalt to trachyandesite rocks are plagioclase, pyroxene and olivine. Bordering to volcanic units, pluton of microgabbroic to microdioritic is exposed. These rocks have a granular texture with essential minerals of plagioclase; pyroxene, olivine and biotite. Multi-element diagrams, normalized to chondrite and primitive mantle, indicates LREE and LILE enrichment and HREE and HFSE depletion such as Ti, Nb and Ta in the studies samples. Based on trace elements ratios diagrams La/Sm vs. La and Zr/Nb vs. La/Yb, parental magmas may have been generated from low degree partial melting of subcontinental mantle source with garnet-lherzolite composition. Post-collisional geotectonic environment of the studied samples and trace element geochemical evidence indicate that produced magma formed from a metasomatic mantle due to ancient subduction.

Formation of clay minerals is affected by soil forming factors which in turn play an important role in soil management. The aim of the present research was to study genesis, classification, and clay mineralogy of Koshkooiyeh-Anar soils. Four representative pedons were studied for physicochemical and clay mineralogy analyses. Gypsic, salic, and natric were among the diagnostic horizons that have been identified by field and laboratory studies. Gypsic Haplosalid and Typic Haplosalid subgroups were classified by Soil Taxonomy. Illite, kaolinite, chlorite, smectite, palygorskite, and sepiolite clay minerals were identified using X-ray diffraction (XRD). In addition, Transmission Electron Microscope (TEM) was also used to prove the presence of fibrous palygorskite clay mineral. Sepiolite is reported in soils of Kerman Province for the first time. A reverse relation between smectite and palygorskite was found in studied soils, thus the maximum content of smectite and palygorskite were identified in surface and subsurface horizons, respectively.

The Mishu garnitoidic complex is cropped out in NW of Mishu mountains, in southwest of Marand, northwest Iran (East Azarbaidjan) which is intruded into Kahar Formation. Based on petrographic studies, this pluton is composed of intermediate rocks including granodiorite, quartzmonzodiorite and diorite. Plutonic rocks are mainly composed of quartz, plagioclase, orthoclase, biotite, amphibole and pyroxene minerals. Amphiboles are one of the most important minerals in intermediate rocks. Based on results of electron microprobe analyses, amphibole minerals are calcic and show magnesiohornblende to actinolitic hornblende and actinolite compositions. Also these Amphiboles have compositional zoning from magnesiohornblende, actinolitic hornblende or actinolite with cores of magnesiohornblende or actinolitic hornblende. Actinolite and actinolitic hornblende rims occured patchy compositional domains or crystal aggregates around subhedral cores of actinolitic hornblende or magnesiohornblende. The mineralogical studies show cores of phenocrysts crystallized under conditions of low oxygen fugacity, indicated by low Mg content.Whereas high Mg content in the rims displays higher oxygen fugacity during their crystallization. There is no evidence for actinolite or actinolitic hornblende resulting from late hydrothermal activity, nevertheless patchy domains of actinolite or actinolitic hornblende are probably the result of subsolidus reactions of clinopyroxene in the presence of exsolved fluid.

This study focuses on the mineralogical and chemical characterization of Mishan Formation marls from North East Ahvaz for brick production. Mineralogical and Geochemical studies were performed by XRD and XRF methods. Major minerals in marls are quartz, calcite, dolomite and the minor minerals are orthoclase, chlorite, and muscovite. Illite and montmorillonite are also present as minor minerals in some samples. SiO2, CaO, Al2O3, Fe2O3 and MgO are the most abundant major oxides. These oxides are effective on the technical behavior of brick raw materials. Raw materials (marls) composition was compared with Iranian National standard permissible limits. The average chemical composition of marls is close to the required amount. From mineralogical and chemical composition point of view, by adding clay admixture to the raw materials, marls of this region can be used for brick and related industries.

The study area is located in west of Iran (38 km SW of Qorveh). This region is part of Sanandaj-Sirjan zone. This area contains several pegmatitic dikes and based on mineralogical and geochemical characteristics belong to muscovite-rare-element pegmatites. The lithology of this body varies from pegmatitic syenogranite to granodiorite. Various rock bodies in this suite are mostly I-type and calc-alkaline, with moderate to high K and regarding to the aluminum saturation degree they are subaluminous to peraluminous. The low (La/Yb) N ratio in the pegmatitic samples (2.28) indicates progression of fractional crystallization in the initial magma. The low Eu/Eu* ratio (0.137) in these pegmatites indicates differentiation of calcic plagioclase before pegmatitic stage. In the spider diagrams, LILE elements such as K, Rb and Th are enriched relative to HFSE elements specially Nb and Ti. Intrusion of this pegmatite in the carbonate rocks led to skarn development. These skarns have different minerals such as tremolite, epidote, scapolite, clinozoisite, pyrrhotite, pyrite, chalcopyrite and magnetite. Based on geochemical characteristics of these pegmatites, their composition, in accordance with bodies, is related to Sn, W and Mo skarns. This fact is in agreement with the studies in area regarding Sn & W mineralization.

Gabbroic complex of Soltan Abad is Located about 35 Km east of Sabzevar. According to tectonic classification, the study area is part of Sabzevar ophiolitic zone. The composition of these intrusion bodies are vary from gabbro to gabbro-diorite. The main minerals of gabbroic rocks are plagioclase (bytonite), clino-pyroxene and ortho-pyroxene (enstatit – hyperestene) and accessory minerals are apatite, sphene, biotite, and opaque minerals (different iron oxides). Secondary minerals are sericite, chlorite, carbonate and tremolite- actinolite. According to the geochemical diagrams, these bodies are tholeiitic and metaluminous - peraluminous. Amphiboles belong to the calcic group. Geothermobarometry of pyroxene, amphibole and plagioclase indicate that the temperature of plutonic rocks formation was between 1000 and 1350 °C. On the basis of geochemical studies and tectonic setting, the gabbroic bodies of SE Soltan Abad are comparable to the volcanic arc basalts and created in the regime of volcanic arc tectonic setting. On the basis of geochemical data and field relation, magmatic source of plutonic complex should have been derived from mantle. This magma is depleted from Ti, Nb and Ba and enriched in K and Rb which indicate the charactristics of subduction setting.

The barite and the behavior of REE in its crystallo-chemical structure have been a major category of research done by scientists for a long time. There are various barite mineralization in Northwest Iran. These sediment-hosted resources as a type of tectonic-controlled-vein mineralization bear unconformity to their shale host rocks at Precambrian age (Riphean). The REE geochemical studies are carried out with the aims to investigate the behavior of REE in barite and galena crystal chemistries and to compare them with respect to their host rocks and some certain standards to reach the aims, Eu, Ce, La anomalies, chondorite normalized ratios, and other standards are used. REE evidences revealed discrepancy between barite-galena mineralization and host rocks. Barite crystallized at oxidized environment, but galena at reduction environment; moreover, barite originated from volcanic sources. Finally it seems that the mineralizations are formed under brine and hydrothermal fluid mixing condition.

HP/LT metabasite rocks can preserve some evidences of tectonic and geochemical processes of a subduction zone. Sabzevar Ophiolite and metabasites which are located at the north of Central Iranian Microcontinent Block (CIM) have preserved such evidences. The metabasites are fossil oceanic crust of Neotethys-related basin. Metabasites are composed of glaucophane schist, amphibolite and greenschist. Major and trace element contents of the rocks indicate that blueschist and amphibolite protoliths were MORB basalts. Rare earth elements show presence of two MORB types, N- and E-MORB. ΣREE is 132-246 (ppm) and 617-744 (ppm) for the N- MORB and E-MORB basalts, respectively.  La/Yb ratio is ranging from 0.43-0.79 for N-MORB and 8.7 and 1.1 for E-MORB. The Mg# ranges are between 0.24-0.27, 0.23-0.24, 0.42 and 0.38 for glaucophane schist, garnet amphibolite, amphibolite and chlorite schist, respectively, which indicates a weak fractional crystallization in the original magma. High pressure rocks were formed due to northward subduction of Neotethys-branch of Sabzevar basin between CIM and Eurasia since Upper Cretaceous to Eocene.

HP/LT metabasite rocks can preserve some evidences of tectonic and geochemical processes of a subduction zone. Sabzevar Ophiolite and metabasites which are located at the north of Central Iranian Microcontinent Block (CIM) have preserved such evidences. The metabasites are fossil oceanic crust of Neotethys-related basin. Metabasites are composed of glaucophane schist, amphibolite and greenschist. Major and trace element contents of the rocks indicate that blueschist and amphibolite protoliths were MORB basalts. Rare earth elements show presence of two MORB types, N- and E-MORB. ΣREE is 132-246 (ppm) and 617-744 (ppm) for the N- MORB and E-MORB basalts, respectively.  La/Yb ratio is ranging from 0.43-0.79 for N-MORB and 8.7 and 1.1 for E-MORB. The Mg# ranges are between 0.24-0.27, 0.23-0.24, 0.42 and 0.38 for glaucophane schist, garnet amphibolite, amphibolite and chlorite schist, respectively, which indicates a weak fractional crystallization in the original magma. High pressure rocks were formed due to northward subduction of Neotethys-branch of Sabzevar basin between CIM and Eurasia since Upper Cretaceous to Eocene.