مجله بلور شناسی و کانی شناسی ایران
سال پانزدهم شماره 2 (پیاپی 30، پاییز و زمستان 1386)

In the west of Marand in Ghekhlar area, the Upper MiocenePleistocene
volcanic rocks, including intermediate to acidic basic alkaline
and lampr~phyric, are extensive exposed. Trachy-andesite rocks of this area
contain carbonatite-silicate xenoliths, which according to mineralogical
studies, are calcite - carbonatite type. The minerals of calcite, diopside,
anorthite, phlogopite, amphibole, apatite, biotite and titano-magnetite are
essential minerals, which belong to calcic and hydrous carbonatite types.
The dacitic volcanic rocks of this area also contain carbonates globules that
formed fr9m calcite and euhedral apatites. These xenoliths are
geochemically characterized by high content ofCaO, Fe203, MgO, P20S, Cr,
Ni, Y, Cu, Zn which are related to host rock. REE pattern displays
fractionated pattern (CelYb)N = 24-29 and lack ofEu negative signature. The
source of these xenoliths can be attributed to disequilibrium partial melting
of metasomatized mantle by either released fluids from subducted slab or
silicate melts derived from melting of subducted slab. Association of
silicates and carbonates in xenoliths can be related to mingling and
immiscible fluids.

The studied area is situated in southwestern Birjand (South Khorasan). Lithologic units which are studied contains part of the late Cretaceous coloured melange, Cretaceous and Paleogen flysh sediments, Neogen congolmerate and Tertiary volcanic rocks. The listwaenite of this area often appears along fault zone, boundary of units, bedding planes and schistiosity as yellow and brownish vein. The effect of CO2 bearing hydrotermal solutions on mentioned units, in suitable physico - chemical and termodynamic conditions, caused Listwaenitization reactions. Field and microscopic' studies revealed that alteration process comprises pre-sta~e reactions (specially serpentine and talc forming reactions in ultrabasic rocks) and main reactions of listwaenitization which in primary mineral paragenesis is changed to silisic - carbonate assemblages listwaenite). Abundance and type of minerals is depended on composition of primary rock, PH, Eh, T, PCOl and PH)o' Microscopic studies and XRD analysis show presence of magnesite, breunerite, dolomite, calcite, smithsonite, quartz, clinochlore, talc, muscovite, chromite, pyrite and magnetite. Also SEM analysis and polyshed section studies represents Fe, Ni, Fe-Ni-Co sulphur that must be considered as pathfinder minerals for prospecting of Au, Ag, Hg, ....

The Kub-e- Zar area is located about 75 Km in southeast of
Semnan. Electron microprobe analyses of plagioclases of mafic
microgranular enclaves and plutonic host rocks from Kuh-e-Zar area display
that they have normal, oscillatory and reverse zoning, so that plagioclase
cores of reverse zoning in enclaves have oligoclase and andesine
compositions and their rims have andesine and laboradorite compositions,
respectively. Investigation of biotite compositions in host rocks show that in
the host granodiorite rocks, there are two types of biotites. The first type has
high Ti02 (mean 4.8%), Alz03 mean 12.84%), MgO (meanI5.38%) and low
Si02 (36.89%), which are similar to mafic microgranular enclaves (mean
Ti02 4.67%, Alz03 13.03%, MgO 15.19% and Si02 37.23%). the second
type is depleted in Ti02 (mean 0.04%) and MgO (mean 0.02%) and enriched
in Al20 3 (mean 18.09%) and Si02 (mean 64.5%). Contents of these elements
in the biotites of host monzodiorite rocks are similar to enclaves. Chemical
compositions of pyroxenes in enclaves are similar in compositions to those
of host rocks. These features, in addition to the patterns and aboundances of
trace elements in enclaves, the presence of inclusions of fine grain biotite
and hornblende in feldspares, synplutonic dykes, the nature of the
plagioclase zoning and etc. display magma mixing and mingling origin for
generation of these enclaves.

Nezamabad region is a part of Boroujerd granitoid comple)( (western Iran) which has been cut by various quartz-tourmaline veins with appro)(imately 0,5 to 2 m thickness, Mineralogical and electron microprobe analyses of the tourmalines in those veins and quartzdioritic host rock show that they are schor! and dravite one in terms of composition (with a general tendency toward dravite end member) and alkaline and calcic type respectively, The FeO*' (FeO*+MgO) ratio of the studied tourmalines are between 0,5 to 0.8, demonstrate that the element·rich fluids have originated from'S; 1 Km for from the veins. Accruing as vein fonn and showing optical zoning as well as widely varying compositions, they have also more magnesium than iron, fluorine amount simi lar to hydrothermal veins and tendency away from alkali· and proton·deficient tourmaline. There fore, it can be concluded that the veins are hydrothermal one and have been formed by dehydration of metamorphosed sedimentary rocks and its mixing with granitic fluids in an open chemical system.

Advanced diode laser consists of a two dimensional thin layer which is about 10 nanometers size. Optical gain of thin layers has a great deal of importance in light amplification. Thin layers cause a modification in conduction and valance bands of bulk materials. · Subbands have been computed through effective mass equations. As a result of this method, particular effective masses are available. These specific equations are formed by numerical methods .Studied structure in this research includes a two dimensional thin layer of GaAs with a quantum well width from 7.5 to 8.5 nanometers, cladded by two layers of AIGaAs which has a larger band gap. Aluminum percentage has been chosen 15 to 45 percent. Results from this study demonstrates that quantum well width should be adjusted according to Aluminum percentage, and the final optimized resu lt, based on the developed optical gain model, is a thin layer of 8.5 nanometers width cladded by a 25 percent of aluminum in AIGaAs materials.

In this research, ZeoliteX (Na&6 [(AI02)&6(Si02)u>6].264H20), has been prepared from 2onouz Kaolin. Then VOX·Zeolite has been obtained by treatment of ZeoliteX with vanadyl sulfate solution .The Salen ligand has synthesized by condensation reaction of salisylaldehyde and ethylendiamine. The encapsulated complex, VO (salen), in zeolite pores was prepared by reaction of salen with VOX·Zeolite in ethanol at reflux temperatur.The product was characterized by FT·IR, XRD and SEM (EDX) techniques.

One of the metamorphic rocks in the Nain ophiolitic mclange is skarn which is fonned during the contact metamorphism of intrusive tonalites with their neighboring limestones and carbonate parts of banded cherts. Minerals of these skarns consist of carbonate (calcite). clinopyroxene (diopside). garnet (grossular-andradite). wollastonite, sphene and epidote. Also tonalites contain quartz, plagioclase (albite). alkali feldspar (orthoclase). garnet (almandine-spessartine) and prchnite, Based on mineral assemblages ofNain skarns as well as geothennometry of feldspars existing in relevant granites and also applications of different calibrations of garnet· clinopyroxene geothennometer. the Nain skams fonn at temperatures of about 440 to 650 °C al low pressure during a contact metamorphism which has occurred at hornblende hornfels to pyroxene hornfels facies.

The mineralogical and geochemical composition of the soils of three representat ive pedons fanned on basaltic andesite, andes itic basalt and phyllite were investigated. Results by XRF showed that progressive weathering of rocks have been marked by gradual accumulation of AI, Fe, Ti, Mg. H30+ and depletion of Na, K, Ca and Si in the soi l; although, predominant clay, loss and gain trend of elements was different on the various rocks. Based on x·ray diffraction analysis, minerals in basaltic andesite and andesitic basalt were similar but, the intensity of mica to smectite or vermiculite transformation for latter was relative ly higher than the former. This process revealed the degradation mineral because of two reasons: ( i) - smectite and vermiculite increased whereas mica decreased in surface horizons. (ii}-Irregular mixed layer of mica-5mectite or vermicu lite was present in deeper part (170 cm) of the soils from andesitic basalt but shallower depth (75 cm) of the soi ls from basaltic andes ite. Clay minerals in phyllite were mica and chlorite that stratified with vermiculite. However, the absence of smectite in phyllite might be attributed to more acidic condition or position of the Fe ion in the mineral lattice of chlorite (higher Fe in the interlayer hydroxide sheet)

This study was done in ehe wet marginal part of the Siahkooh playa (Kevir) in Yauf. Iran. which is located in the northwest of Ardakan. The abundance of Ca and SO. iones led to gypsum crystallization ncar the water table in the soil. From depeh to the soil surface, the caC~- CaSO .. ,2H,O -NaCI-H,<)-PCo, soil and water system change to CaSO •• 2H,<)Na1SO .. ·NaCI· Hz{). From water table (I00cm under soil surface) to the soil surface. ionic power was decreased and activty coefteient was incrased respctivcly. Therefore. ncar ground table, gypsum fonn and high concentration of Ca iones from gypsum lead to low amounts of exchangeable Na. This influence has been continued up to soil surface to achieve a relative balance. Replacement ofNa with Ca on the exchangeble surfaces of soil and ex~ of SO .. ioncs formed NaSO .. ineraJs. The precipitation of 1800ton per hectar natrium salts(sulfatic &. coloridic) was estimated wjth respect to the mean of annual evaporation (roughly 900mm) in the studied site. The result also showed that the seventh bands ofI .. odsal7 are more important to diferentiate between sulfate and chloride salts as well as sodium and calcium salts.

The BiI.7Sbo.JSr..,.,cal.OlCuJ.IOy superconductors are prepared by sol·gel method and the effect ofW~ and MnOz additives on their properties are studied. Structural studies show that the find samples are homogeneous and are mainly composed of 2223 and lower percents of 2212 phases. Analysis ofthe X-ray diffraction patterns indicate that the penetration of~ ions into superconducting phase considerably increases for more than 2 wt% additives. Also. the penetrating ~ ions preferentially occupy 4e and 2a crystallographic sites of eu atoms. The electrical measurements show that the best superconducting properties obtain for the sample with I wt% of WOJ additive, while superconductivity is weakened for higher amounts of WO,. For the sample with O.S wt% of MnOz additive, the best superconducting properties are obtained after sintering at 830 OC.

the Siahkuh playa is one of the greatest deserts in Yu.d province and is located in the north-north eastern of Ardakan city. In playa regions, different sub-environments with different mineral potentials can be recognized. In Siahkuh playa, various evaporite minerals such as gypsum in different form (sugery, nodular and euhedral crystals), halite (fibrous, cylindrical, hopper-shaped crystals and ball-shaped), and sodium sulfate were indentified. Sodium su lfate (Thenardite) is a commercial chemical compound which is formed in playas environments. This compound was also found for the first time in mud flat sub-environment of SW of Siahkuh playa. In brine waters of salt lakes sub-environment of Siahkuh playa. various elements such as lithium, magnesium, calcium, potassium and sodium were detected.

The alka line and calc-alkaline volcanic activities in Mianch have reactivated the hydrothermal so lutions, resulting in the fonnation of epithermal mineralization in the region. The mineralized zone trending NWSE, and has been affected by NE-SW bended and folded structures. The precious and base metals mineralization are confined to structurally hended zone. Landsat-7(ETMJ data were used to study the alteration zones, structural features and to discriminate the lithological units in the region. The primary corrections were carried out on the images and the data resampled to 1 Sm. Based on spectral pattern of minerals present in the alteration system, such as chlorite, epidote, kaolinite, jarosite, geotite, hydrothermal alteration zones of the area were detected using band ratio and principle component analysis (PCA) techniques, which also well correlated with field studies. The linear and ring structural features along with lithological units were discriminated based on spectral features of minerals. Ultimately, the study reveals that the application of PCA resulted in enhancement of alteration halos. The field checks have confinned the achievement and indicate the western part of the area as potentially promising zone.

Dodehak granitoid stock with tonalite to granodiorite compos ition is exposed south of Dodehak vi llage, north of Ab-e-Gann (Mahalat) in Urumieh-Dorhtar volcanic belt of Iran. Based on petrography and point analysis (EPMA). plagioclase crystals show nonnal zoning with graph ic tex.ture is present. Samples from SE of the intrus ion are different and myrmekite texture is present in the rocks, while graph ic texture is absent and plagioc lases have lost their zon ing. In samples from SE of the area. mynnekite is rim type and plagioc lases show cross shape twinning. Based on whole rock XRF analyses, Rb-S i~ and K20 -Na10 diagrams show nonlinear trends and EPMA analysis indicate that plagioc lases are homogeneous albite. Such petrographical and geochemical features are evidence for alkaline metasomatism in SE of the Dodehak intrus ion.

Mantle peridotites are one of the most important rock units of
Jandaq ophiolite that are affected by numerous,phases of dynamic and static
serpentinization, and metamorphism. The main part of mantle peridotites is
lherzolite. This ophiolitic association is covered by Paleozoic metamorphic
rocks that are schist and marble. All olivines are changed to serpentine. Most
of orthopyroxenes are bastitized and some of clinopyroxenes are changed to
tremolite by metamorphism. Clinopyroxenes are the most resistant mineral
against the metamorphism and alteration. Most of spinels are magnetitized,
but in some cases the inner parts are fresh. Composition of chromian-spinels
are the same in all mantle peridotites with CrN "" 0.46. Gabbros that intruded
the peridotites are rodingitized. Peridotites of Jandaq ophiolite are abyssal
peridotites that belong to spinel lherzolite facies. Crystallization temperature
of pyroxenes in Iherzolites ranges from 1041 to I 178 DC. One of the most
characteristics of these peridotites is absence of chromitite that relates to
lherzolitic system of mantle, low degree of partial melting, low activity of
mantle in continual ascending melt production, and low Cr content of
pyroxenes.

Contact metamorphism in the Shahindezh Metamorphic Core
(SMC), which is occurred due to intrusion of Pichaghchi granodiorite during
Laramian orogeny (Upper Cretaceous), is studied here. The well deve loped
mineral parageneses at the aureo le is quatz + plagioclase + biotite +
cordierite ± chlorite ± K-feldspar ± muscovite ± andalusite ± sillimanite ±
garnet. Pressure and temperature of the contact metamorphism at the SMC
for andalusite + cord ierite -bearing assemblages (the most common
paragenesis at the aureole) are estimated -3.5 ± 1.5 kbar and 500 ± 50°C
using THERMOCALC computer program. Also the exact pos ition of the
muscovi te + biot ite breakdown reaction at the PT space, is calculated.
Temperature for muscovite-biotite breakdown was about 650 ± 40°C at 3.5
kbar. The calculated position of the reaction curve, is in good agreement
with publ ished experi mental data. The metape lites at the north-eastern part
of the SMC contain hi gh-temperature assemblage quartz + biotite + garnet +
sillimanite + plagioc lase ± cordierite ± K-fe ldspar. The mineral assemblages
and reaction textures in the aureole rocks record temperature about <750 °C
at the si llimanite -cordierite zone and pressure - 4 kbar, detennined using
petrogenetic grids. In the partially molten rocks garnet porphyroblasts are
associated with coarse-grained quartz. Cord ierites occurred both at the rims
of res idual garnets crystallized during regional metamorphism and in the
matrix. All cordierites are altered to pennite. Fibrolite inc lusions in the
matrix cordierites are common.