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Volume 29, Issue 114 , December 2019, Pages 2-2
Original Research Paper
Economic Geology
Majid Hafez Darbani; Ali Abedini; Farhang Aliyari; Ali Asghar Calagari
Abstract
The Kuh-Baba iron ore deposit is located in ~70 km south of Hashtroud, East-Azarbaidjan province, NW Iran. The lithologic units cropped out around this deposit include Oligo-Miocene volcanic-sedimentary rocks, Pliocene intrusive rocks, and Pliocene dacitic domes. The principal host rocks for the Fe mineralization ...
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The Kuh-Baba iron ore deposit is located in ~70 km south of Hashtroud, East-Azarbaidjan province, NW Iran. The lithologic units cropped out around this deposit include Oligo-Miocene volcanic-sedimentary rocks, Pliocene intrusive rocks, and Pliocene dacitic domes. The principal host rocks for the Fe mineralization include units of gabbro-norite, pyroxene hornblende gabbro-norite, and monzo-diorite. Remote sensing investigations (using Sentinel satellite images) display the presence of lineaments, NE-SW trending fault structures, and various alteration zones. The dominant hydrothermal alteration in inner parts of the deposit is mainly propylitic (epidote, chlorite, sericite) which gradually changes to argillic outward toward the peripheral parts. Based upon field relations and microscopic examinations, the ores show massive, vein/veinlet, brecciated, and disseminated textures. In the propylitic zone, magnetite is accompanied by epidote and actinolite. The geochemical studies revealed that the FeT content in the diamond drill core samples varies from 3.85 wt% to 63.2 wt%. Ground magnetic survey was conducted in the area and also, the maps of total magnetic field, reduced to pole magnetic, analytic signal, first vertical derivative, and upward continuation were prepared in an attempt to identify the potential deep and shallow subsurface mineralized zones. The obtained results show that two anomalies, one in the north and the other in the central parts of the study area, were recognized which almost correspond with the location of the intrusive bodies.
Original Research Paper
Petrology
Ashraf Torkian; nafiseh salehi
Abstract
The Ahmadabad, Tahmoures and Ghareh-toreh volcanoes are part of the volcanic centers located on the Qorveh-Bijar axis and constitute a part of the magmatic outcrops of the northern arm of the Sanandaj Sirjan Zone, Hamadan-Tabriz. Volcanic rocks have basaltic composition and show porphyritic, microlithic ...
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The Ahmadabad, Tahmoures and Ghareh-toreh volcanoes are part of the volcanic centers located on the Qorveh-Bijar axis and constitute a part of the magmatic outcrops of the northern arm of the Sanandaj Sirjan Zone, Hamadan-Tabriz. Volcanic rocks have basaltic composition and show porphyritic, microlithic porphyry and glomeroporphyritic textures. Major phenocrysts include clinopyroxene and olivine. The abundance of clinopyroxene is found to be lower in Ghareh-toreh basalts, olivine is major phenocryst in this center. Clinopyroxene phenocrysts show normal, in some cases, reverse zoning and gulf corrosion indicating disequilibrium with the host's melt. The results of thermobarometric calculation (temperature and pressure) using clinopyroxene mineral indicate the temperatures of 1100-11300 °C and pressures of 3 to 11 kbar for Ahmadabad and Tahmoures volcanoes, and volcanic basalts at Ghareh-toreh reveal the temperature of 800 Up to 1100 °C and pressure of 0 to 3 kbar. The high oxygen fugacity in these rocks and the coherence of the temperature and pressure of the olivine phenocryst in this region with the temperature and pressure of the clinopyroxene in Ahmedabad and Tahmoures, all show that clinopyroxene crystals of Ghareh-toreh volcano formed at a lower depth and possibly in a shallow reservoir
Original Research Paper
Geophysics
Mojtaba Naghavi; Habib Rahimi; Ali Moradi
Abstract
In this study, we have used recorded local earthquakes by 17 permanet seismic stations to separate intrinsic and scattering attenuation in North-West of Iranian pleateau. Intrinsic and scattering attenuation can be applied as useful tools to study the geodynamic and tectonic characteristics of a region. ...
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In this study, we have used recorded local earthquakes by 17 permanet seismic stations to separate intrinsic and scattering attenuation in North-West of Iranian pleateau. Intrinsic and scattering attenuation can be applied as useful tools to study the geodynamic and tectonic characteristics of a region. They also represent thermal, compositional and deformational characteristics of the crust and upper mantle. The wave attenuation has strong correlation with seismicity and heterogeneity of medium and is regularly used in the study of tectonically active regions of the world. Single backscattering and coda normalized methods are used to estimate the coda Q (Qc) and Qs respectively, using 14,969 earthquakes which are recorded by the stations. The results show this region is very active region tectonically and seismically. Due to low values of Quality factor and thus high attenuation values of body and shear waves in North West part of Iran, amplitude of the propagated waves are decreased severely in the interested area.The intrinsic attenuation and the Coda wave attenuations curves around the North Tabriz fault are closer in comparison with entire northwestern Iran region and Tabriz city, indicating a strong attenuation of the earthquake waves around this fault system. Similarly, these curves are closer in Tabriz city than those calculated for the northwestern region of Iran which expresses the overriding intrinsic attenuation from the effect of dispersion. The attenuation effect of seismic waves reduces the damages caused by earthquakes at appropriate distances of faults at the time of earthquake occurrence.
Original Research Paper
Petroleum geology
kambiz Mehdizadeh farsad; davood Jahani; alireza hajian; Fereidoun Rezaei
Abstract
Hydraulic fracture is known as one of the effective methods for producing or being caused a change in the physical structure of a reservoir rock. In oil and gas reservoirs which have been fractured by a hydraulic approach, this method causes that a production well and the time of reservoir production ...
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Hydraulic fracture is known as one of the effective methods for producing or being caused a change in the physical structure of a reservoir rock. In oil and gas reservoirs which have been fractured by a hydraulic approach, this method causes that a production well and the time of reservoir production increase. In this research, fracture analysis have been comprised with the outputs produced by previous models. Its results show that the opening intersection produced by hydraulic fracture has been being changed in various time during pumpage, therefore, the fracture should be kept open by propanent substances. In the next stage, the amount of porosity pressure in the trend of the fracture is considered. In this survey, two parameters, i.e. the fracture measure and the change of pore pressure have been obtained using the hydraulic fracture modeled process under the actual condition of pay zone and its confining layers, and by the finite element approach. In this method, pumping processing has been assigned for fluid and propanent. At the end, by making a comparison between these result and the results obtained from previous studies, it can be found out that this approach is applicable and efficient.
Original Research Paper
Petrology
Marziyeh Abazari; Seyyed Saeid Mohammadi; Malihe Nakhaei
Abstract
Abbas Abad area is located in the northeast of Sarbisheh, in the northern part of Sistan suture zone and southern Khorasan province. In this area, Tertiary volcanic rocks with the composition of intermediate to acid, including basaltic andesite, andesite, and dacite are exposed. Constructive minerals ...
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Abbas Abad area is located in the northeast of Sarbisheh, in the northern part of Sistan suture zone and southern Khorasan province. In this area, Tertiary volcanic rocks with the composition of intermediate to acid, including basaltic andesite, andesite, and dacite are exposed. Constructive minerals of basaltic andesite include of plagioclase, pyroxene and olivine and in andesite consist of plagioclase, hornblende and pyroxene, and in dacite are plagioclase, quartz, biotite and hornblende. The studied rocks have medium to high-K calc-alkaline nature. Most samples show enrichment in LILEs (K, Rb, Sr, Cs) (except Ba) relative to HFSEs (Y, P, Ti, Ta, Nb), which indicates the relation of these rocks to subduction zone and active continental margin. The relatively low (La/Yb)N (7.67 to 13.48) and Dy/Yb (<2) in Abbas Abad lavas indicate that partial melting of mantle occurred in transitional zone of spinel-garnet lherzolite. Based on the concentration of trace elements such as Ce, Yb and Sm, magma originated from a depth of about 95 to 105 kilometers.
Original Research Paper
Stratigraphy and Palaeontology
Mahin mohamadi; R. Shabanian; H. M. Alizadeh
Abstract
This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field ...
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This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field study and lithological diversity 8 lithic zone have been investigated. 102 samples have been picked up systematically from this sequence. This study lead to determining 41 species from 15 genera of planktonic foraminifera.The systematic and classification of fauna are based on The (Postuma 1971) , (Caron1985) , (Loeblich and Tappan 1988) and (Permoli Silva And Verga 2004). .Based on their range chart the bio zonation model for this deposit with 9 Bio Zones as bellow have been suggested and have compared with cretaceous global standard bio zones (Robazynsky and Caron 1985) and (Permoli Silva and Verga, 2004) Dicarinella concavata Interval Zone (Robazynsky and Caron, 1995) Dicarinella asymetrica Total range Zone(Robazynsky and Caron, 1995) Globotruncanita elevata IntervalrangeZone(Robazynsky and Caron, 1995) Globotruncana ventricosa IntervalZone (Robazynsky and Caron, 1995) Rodotruncana calcarata Total range Zone(Robazynsky and Caron, 1995) Globotruncanella havnensis Partial Range Zone (Robaszynski and Caron, 1985) Globotruncana aegyptiaca Interval Zone (Robazynsky and Caron, 1995) Gansserina gansseri Interval Zone (Robazynsky and Caron, 1995) Abathamphalus mayaroensis Total range Zone(Robazynsky and Caron, 1995) The suggested age for th.is sequence based on planktonic foraminifera is upper coniantian to upper Maestrichtian and belong to deep shelf area . Based on the morphology of planktonic foraminifera and their keei we suggest deep sea environment for these deposits.
Original Research Paper
Petrology
Mahnoush Bahjati; A. Ahmadi; Habib Biabangard
Abstract
The volcanic rocks of Kuleh sangi-Malek siah kuh igneous complex consist of alkalibasalt, basalt, basaltic andesite, andesite, dacite and trachyte. In the SiO2 versus K2O diagram, the basaltic samples are plotted in the shoshonitic field and the subalkaline samples are plotted in the medium K calc alkaline ...
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The volcanic rocks of Kuleh sangi-Malek siah kuh igneous complex consist of alkalibasalt, basalt, basaltic andesite, andesite, dacite and trachyte. In the SiO2 versus K2O diagram, the basaltic samples are plotted in the shoshonitic field and the subalkaline samples are plotted in the medium K calc alkaline series field. The average La/Yb, Rb/Zr and Cs/Hf ratios in basalts are 7, 47 and 63 times those of N-MORB, respectively. Considerable enrichment of LILEs, LREEs and relative depletion of HREEs indicate that the magmas originated from a mantle source more enriched than that of OIB, where phlogopite and garnet are stable. Using non-modal batch melting model, the compositions of the mafic samples are mainly consistent with about 5% melting of a phlogopite-bearing and garnet-bearing lherzolite with a mixture of about 80% and 20%, respectively. AFC models using Pb versus Ce/Pb and Rb versus K/Rb, show that the fractionated samples have undergone simultaneous crustal assimilation and fractional crystallization. It seems that the assimilation and the fractionation had been taken place with the same rate. Depletion in Y and elevated ratio of Sr/Y of fractionated rocks in addition to Rb/Nb ratio more than 8, could be considered as evidence for crustal assimilation.
Original Research Paper
Tectonics
Zeinab Etemadkhah; Mohammd Mahdi Khatib; Mohammadhossein Zarrinkoub
Abstract
The late Paleocene – early Eocene granitoid intrusions in the northern Sistan suture zone are regarded as potential tools to record tectonic events. A structural study of the Zahri granitoid body, based on the anisotropy of magnetic susceptibility (AMS) technique provides new data to characterize ...
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The late Paleocene – early Eocene granitoid intrusions in the northern Sistan suture zone are regarded as potential tools to record tectonic events. A structural study of the Zahri granitoid body, based on the anisotropy of magnetic susceptibility (AMS) technique provides new data to characterize the internal structure and the kinematic reconstruction. The NW–SE trending body consists basically granite to leucogranite. Based on the results of the analysis of over 360 samples collected from 36 sites, the granitoid body is characterized by a low susceptibility and petrographic observations indicate that paramagnetic minerals such as biotite and amphibole are the most important iron-bearing mineral and can be considered as the main carrier of magnetic susceptibility. Magnetic foliations dominated by moderate dip and foliation strike mostly parallel to the elongated shape of the body, the magnetic lineation mainly trends NE-SW to N-S with plunges to the SW (mean orientation N 197°/32°) and formed during the emplacement and crystallisation of the magma. The Zahri body emplaced in an extensional setting controlled by a NNE-SSW opening direction associated with spaces of the sinistral shear zone in the terminations of Nehbandan fault system during the early Eocene.
Original Research Paper
Hydrology
hassan zia; Goliam Hossan Karami; Ali Taheri
Abstract
Estimation recharge is an important parameter in the hydrogeological study that used for water budget. Recharge potential map prepared based on spatial maps of eight major influencing factors on groundwater recharge rates (lithology, slope value, aspect, drainage density, precipitation, fracture density, ...
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Estimation recharge is an important parameter in the hydrogeological study that used for water budget. Recharge potential map prepared based on spatial maps of eight major influencing factors on groundwater recharge rates (lithology, slope value, aspect, drainage density, precipitation, fracture density, karstification and epikarst) were integrated using GIS after expertise judgment. The study area has been classified into four zones with potential recharge of 15, 25, 35 and 45 percent. The extent of each zone was determined 251, 879, 943 and 200 km2, respectively. The average potential recharge was 30% in the study area. According to potential recharge and average of annual precipitation (164 mm), the total recharge in the Shotori mountains was estimated to be 122 million cubic meters (MCM) and about 25 MCM from that volume were discharged from springs and abstraction wells and remaining volume (87 MCM) is recharging to adjacent aquifers. Ezmigan, Ganbar, and Korit are the major karstic springs that drain the Shotori Mountain with the mean discharge rate of 63, 60 and 24 lit/s and electrical conductivity values of 601, 1640 and 825 µS/cm respectively. The estimated catchment area based on the recharge rate in comparison to the evaluated catchments by geological, stratigraphical methods showed that the difference is less than 15%, which confirms the estimated amount of recharge.
Original Research Paper
Stratigraphy and Palaeontology
Abbas Ghaderi; Mahdi Badpa; Ali Reza Ashouri
Abstract
To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals ...
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To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals were determined. The Permian succession of the Julfa area is the dominion of two types of coral fauna. Waagenophyllidae fauna that is the territory of the colonial coral forms comprises typically Tethyan indicators such as Ipciphyllum and Waagenophyllum with the age of Middle?- Late Permian. Cyathaxonia fauna, Late Permian in age, include terminal phylogenetic representatives of the rugose corals, mostly composed of solitary one Pentaphyllum. This genus is persistent till the vicinity of the extinction horizon at the near end Permian in the Ali Bashi Formation topmost horizon. Also, the last standing tabula coral before the Late Permian extinction in the Julfa region is the genus Protomichelinia. The Permian coral fauna of the NW Iran finely corresponds to those of the Abadeh region in Central Iran and Transcaucasus. The Waagenophyllidae forms are the same as South China fauna, whereas the Cyathaxonia ones reveal a high endemism in the Late Permian of NW Iran.
Original Research Paper
Economic Geology
iman shojaian; A. Akbarpour; Khalil Baharfirouzi; Majid vanaei
Abstract
The Darreh Rahim Iron deposit occurred in 2km northwest of Ghohroud village, 25 km south of Kashan city, in Ghamsar county suburb, Isfahan province, on Urumyeh-Dokhtar magmatic belt. . Based on the petrography data, the main intrusive body of the district has medium to coarse granular texture and granodiorite ...
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The Darreh Rahim Iron deposit occurred in 2km northwest of Ghohroud village, 25 km south of Kashan city, in Ghamsar county suburb, Isfahan province, on Urumyeh-Dokhtar magmatic belt. . Based on the petrography data, the main intrusive body of the district has medium to coarse granular texture and granodiorite rock composition. Injection of this intrusive body in the Cretaceous age limestone caused the formation of skarn processes and related Iron mineralization. An assemblage of pyroxene, chlorite, garnet, calcite and quartz are the main components of skarn and also gang minerals of the ore. Also all evidences of mineralogy, structure and texture, geochemistry and tectonic setting and Ni/(Cr+Mn)toTi+V andCa+Al+Mn toTi+V diagrams showed a similarity of the DarrehRhim ore deposit to Iron-Copper mineralization.
Original Research Paper
Geophysics
Jafar Jaghouri; Hossein sadeghi; Sayyed Keivan Hosseini
Abstract
The shear wave quality factor is one of the key parameters for earthquake and engineering seismology studies. In the present study, this factor was investigated in the region of the 2012 Ahar-Varzaghan twin earthquakes. We used a generalized inverse method based on the shear wave windows of the aftershocks ...
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The shear wave quality factor is one of the key parameters for earthquake and engineering seismology studies. In the present study, this factor was investigated in the region of the 2012 Ahar-Varzaghan twin earthquakes. We used a generalized inverse method based on the shear wave windows of the aftershocks of these two earthquakes. 2860 records of broadband three-components and 540 records of short-period single-component from 1,650 aftershocks with a magnitude of 0.2 to 3.0 were used. The records of the aftershocks obtained within 29 days by a temporal seismic network by the Earthquake Research Center - Ferdowsi University of Mashhad at five broad-band and five short-period stations. Since the generalized inverse method needs a reference site to remove the source effect, the choice of the reference site was done using the results of the H/V spectral ratio method at the broad-band stations, as well as the topographic location of the stations. The frequency dependence of the was regressed in the range of 0.1 to 10 Hz and as Q_s=43 f^1.52 . This low value and high frequency-dependency can be attributed to the high heterogeneity of the crust and the active seismicity of the region.
Original Research Paper
Stratigraphy and Palaeontology
Ghamarnaz Darabi; iraj Maghfouri Moghaddam; Abbas Sadeghi; Bizhan Yusefi
Abstract
In this study, biostratigraphy and Paleobathymetry of the Gurpi Formation in section southwest of Kuhdasht were studied. The thickness of Gurpi Formation in this section is 160 meters and its main lithology includes Marl, Limy Marl, Limestone and Shale. In this section Lower boundary of Gurpi Formation ...
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In this study, biostratigraphy and Paleobathymetry of the Gurpi Formation in section southwest of Kuhdasht were studied. The thickness of Gurpi Formation in this section is 160 meters and its main lithology includes Marl, Limy Marl, Limestone and Shale. In this section Lower boundary of Gurpi Formation is transition with Ilam Formation, and its upper boundary with Amiran Formation is unconformably. Here, on the basis of foraminiferal studies,50 species belonging to 24 genera of planktic foraminifera and Benthic were identified. Based on the stratigraphic distribution of the well known foraminifers, six foraminiferal biozones were established in the Gurpi Formation including: Globotruncana ventricosa Interval Zone, Radotruncana calcarata Taxon Range Zone, Globotruncanella havanensis Partial Range Zone, Globotruncana aegyptiaca Interval Zone, Gansserina gansseri Interval Zone, Contusotruncana contusa Interval Zone.The age of Gurpi Formation in this examined is determined based on identified biozones of Middel Campanian to Late Maastrichtian. A depth of 450 - 600 m was assigned for most parts of the sediments Gurpi Formatan was assigned ccording to planktic/epibenthic ratio and Percentage Morphotype 3 and the regression equation Depth = e (3.58718 + (0.03534 × %P*))
Original Research Paper
Hydrology
Shahrokh Norallahi; A. Asghari Moghaddam; Fijani Elham; Rahim Barzegar
Abstract
In recent decades, due to growth of population and qancequently increasing demand for drinking, agriculture and industry purposes has led to consider the groundwater as the most important resource of water in the area. Therefore, it is necessary to pay attention to the quality of the groundwater in the ...
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In recent decades, due to growth of population and qancequently increasing demand for drinking, agriculture and industry purposes has led to consider the groundwater as the most important resource of water in the area. Therefore, it is necessary to pay attention to the quality of the groundwater in the area, along with its quantity. The objectives of this study are to investigate the possible origin of some heavy metals in the groundwater of Mashgin-Shahr plain using multivariate statistical methods including cluster analysis and factor analysis along with correlation coefficient as well as identification of factors affecting groundwater quality in the area. For this purpose, 25 groundwater samples were collected in October 2016, and measured with respect to pH, electrical conductivity, major (calcium, magnesium, sodium, potassium, chloride, sulfate, carbonate, and bicarbonate) and minor (nitrate, fluoride and silica) ions and some heavy metals/metalloid such as iron, manganese, aluminum, zinc, chromium, copper, cadmium, lead and arsenic. The analyzes show that processes such as weathering and dissolution of evaporatic and silicate formations, ion exchange and agricultural activities are effective on the groundwater quality of the area. The results of multivariate analysis show that most of the heavy are originated from volcanic formations in the area and salinity and acidity play an important role in releasing them into the groundwater. Factor analysis indicates that geogenic processes with a total of 79.9 % of variance and anthropogenic factors with a total of 6.6 % of variance control the groundwater chemistry.
Original Research Paper
Petrology
Mohsen Moayyed; Mohamad Amin Safikhani; Robab Hajialioghli; Nasir Amel; Ahmad Jahangiri
Abstract
The study area is located at the Mishow mountain ranges in NW Marand town. The main outcropping rocks are Pliocene volcanic and volcaniclastic rocks. Lamprophyre, mica pyroxenite, amphibolite and carbonate rocks occure as xenoliths within andesites. The main rock forming minerals for lamprophyre xenolith ...
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The study area is located at the Mishow mountain ranges in NW Marand town. The main outcropping rocks are Pliocene volcanic and volcaniclastic rocks. Lamprophyre, mica pyroxenite, amphibolite and carbonate rocks occure as xenoliths within andesites. The main rock forming minerals for lamprophyre xenolith are coarse grained biotite, clinopyroxene and rare plagioclase within a matrix composed of the same crystals with porphyric and hyaloporphyric textures. These can be classified as kersantite. Mica pyroxenite xenolith is composed of clinopyroxene, biotite, plagioclase, (±) hornblende and opaque phases. Plagioclase, clinopyroxene as well as rare amphibole and biotite are seen as scattered magmatic crystals within carbonate matrix in the carbonate xenolith. On the basis of mineral chemistry of clinopyroxene, magma nature for the lamprophyre and mica pyroxenite xenoliths has been detremined as calc-alkaline. Clinopyroxene composition indicates high fugacity of oxygen for lamprophyre and mica pyroxenite xenoliths. The estimated temperatures are 1100C-1200C, 1080C-800C for mica pyroxenite and lamprophyre respectively at pressures of 5-10 kbar. The pressure and temperature of amphibolite xenolith have been estimated based on amphibole geothermobarometer as 750-800 (±12oC) and 6.2±0.6 kbar, respectively.
Original Research Paper
Petrology
Mahin Hashemi; Nahid Shabanian; Alireza Davoudian; Hossein Azizi
Abstract
Estimation of temperature- pressure deformation path for metamorphic rocks experiencing a complex deformation history commonly rely on the relationship between successive metamorphic assemblages and different microstructures that remain. However, by changing the temperature-pressure conditions, metamorphic ...
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Estimation of temperature- pressure deformation path for metamorphic rocks experiencing a complex deformation history commonly rely on the relationship between successive metamorphic assemblages and different microstructures that remain. However, by changing the temperature-pressure conditions, metamorphic minerals with a microstructure, which are specific to those conditions, can be chemically re-equilibrate. Mylonitic paragneisses around the lake of Zayandehrood Dam, have range low-grade to medium-grade mylonites. According to petrographic and microstructural studies, we define at least three stages of metamorphism and deformation. The first stage metamorphism (the earliest recognizable metamorphic stage) took place during eclogite facies conditions. At this stage, high pressure minerals such as rutile, phengite, garnet and alkali-feldspar formed that enclosed in garnet or feldspar, and or located in matrix. These hosted garnets and feldspars based on the evidence of petrography formed at the amphibolite facies condition. Eventually a retrograde metamorphism took place in the lower green schist facies condition, That's evidence includes the sericitization of some feldspars, the chloritization of some biotite, and the formation of cholorite and quartz in and around some garnets. contemporaneous whit these retrograde processes, there is evidence of a relatively high temperature to low temperature deformation microstructure. The combination of evidences of metamorphism and deformation results is that these rocks have risen from relatively high depths, which during the rising stages undergone the various metamorphism condition, and many deformations have affected on this collection.
Original Research Paper
Tectonics
Zahra Mohammadyasl; Abdollah Saidi; Mehran Arian; Ali Solgi; taher Farhadinejud
Abstract
The Studied area is located in the small part of the structural zone of Urumieh- Dokhtar Magmatic Arc, at 60km far from south of Qom and 12km far from south east of Kahak. In the beginning, 1:25000 map of the area was prepared, because, region is located in two 1:100000 scale map sheet of Kahak and Aran, ...
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The Studied area is located in the small part of the structural zone of Urumieh- Dokhtar Magmatic Arc, at 60km far from south of Qom and 12km far from south east of Kahak. In the beginning, 1:25000 map of the area was prepared, because, region is located in two 1:100000 scale map sheet of Kahak and Aran, and more rock units were separated. In the next step, in a several step of the field observations, 17 samples of regional volcanic rocks were taken for XRF and ICP chemical analysis, and they main Oxides, heavy metals and rare elements were identife. Most of the samples have been located in the Calk- alkaline series, and some in the Tulleit series. In the lithology diagrams, these samples respectively are arranged in the range of Andesite, Dacite, Trachy Andesite and Rhyolite Rocks. Due to the anomalies and the amount of Nb in the samples of the region, they formation can be related to the subduction zone. On the other hand, the depletion of Nb and Ti is special in magmatism in the subduction zone. Because in the subduction regions released fluids from floating lithospheric rich in LILE, increases in the mantle wedge. Since in the study area rocks exhibit calc- alkaline with moderate to high potassium, it can be concluded that the stones are related to active continental margin associated with subduction.
Original Research Paper
Petrology
Leila Maleki; Nematollah Rashidnejad Omran; Abdolrahim Houshmandzadeh
Abstract
Boneh shurow metamorphic complex is located in the east of Saghand area, Central Iran. This complex consists of quartz-feldspatic gneiss (mafic minerals < 5%), biotite-amphibole gneisses, metabasics rocks, schists, subordinate dolomitic marble and quartzite interlayers and mafic and felsic magmatic ...
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Boneh shurow metamorphic complex is located in the east of Saghand area, Central Iran. This complex consists of quartz-feldspatic gneiss (mafic minerals < 5%), biotite-amphibole gneisses, metabasics rocks, schists, subordinate dolomitic marble and quartzite interlayers and mafic and felsic magmatic intrusions that they have been retrogressed to lower amphibolite facies. In MORB-normalized plots, the metabasic samples can be classified into two groups: first group does not display Nb-Ta anomaly and second group displays negative Nb-Ta anomaly. Whole rock geochemistry and Sr– Nd isotopic composition of metabasic unites suggest derivation from two different mantlic sources in the back arc setting. A source enriched in Ti, such as plume tail, and an old enriched mantle that has been affected by subduction, can be involved in generation of the first and second group, respectively
Original Research Paper
Sedimentology
Yazdan Golestan; Umid Kakemem; Mohammad Adabi; E. Dehyadegari
Abstract
Carbonate-evaporate succession with siliciclastic sediments and mixed siliciclastic carbonate deposits of Asmari-Pabdeh reservoir in Karanj Oil Field with Oligo-Miocene in age was studied to determine diagenesis, microfacies and original carbonate mineralogy. Micritization, dissolution, compaction, neomorphism, ...
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Carbonate-evaporate succession with siliciclastic sediments and mixed siliciclastic carbonate deposits of Asmari-Pabdeh reservoir in Karanj Oil Field with Oligo-Miocene in age was studied to determine diagenesis, microfacies and original carbonate mineralogy. Micritization, dissolution, compaction, neomorphism, cementation and dolomitization are the main diagenesis processes that effect Asmari-Pabdeh successions. Petrographic studies led to identification of three types of dolomite such as dolomicrite, dolomicrosparite and dolosparite, in which dolomicrosparite and particulary dolospatite caused increase in reservoir quality. Eleven carbonate-evaporate microfacies were identified. These deposited in four major environments comprises of tidal flat, lagoon, carbonate shoal and open marine. Sedimentary environment of the Asmari Formation recognized as a homoclinal ramp. Diagenetic studies reveal impact of marine, meteoric and burial diagenesis on the deposits. Geochemistry of minor and major elements reveal original aragonite mineralogy for carbonates of the Asmari Formation. The high Sr/Mn and Sr/Ca and minor amounts of manganese implying close diagenetic system with low Water/Rock interaction for the Asmari Formation succession.
Original Research Paper
Economic Geology
yegane khoramtash; farajolah fardoost
Abstract
The Saghari copper deposit is located 120 Km at Southwest of shahrood, within in the eastern part of Toroud-Chahshirin magmatic arc. Mineralization in the Saghari area occured within volcanic and pyroclastic units of Eocene. Based on the field, laboratory investigations and geochemical analysis, the ...
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The Saghari copper deposit is located 120 Km at Southwest of shahrood, within in the eastern part of Toroud-Chahshirin magmatic arc. Mineralization in the Saghari area occured within volcanic and pyroclastic units of Eocene. Based on the field, laboratory investigations and geochemical analysis, the outcropped rocks in the Saghari deposit are andesite, andesite-basalt, basalt, dacite and several exposures of pyroclastic rocks such as tuff and agglomerate. The rocks are high-k, calc-alkaline to a small amount of shoshonitic in nature, and are formed at a magmatic arc setting in a subduction zone. Basic to intermediate dyke bodies intruded Eocene volcanic-pyroclastic sequences. The host rocks have been affected by argillitic, sericitization, chloritzation, carbonatization and oxide-Fe (limonite, hematite and goethite). The textures and structures of mineralization are vein-veinlet, replacement, open space filling and disminated. According to the mineralography studies, main minerals of copper are malachite, chalcocite, covellite, chalcopyrite, chrysocolla and rare native copper. Malachite and chalcosite are the most abundant minerals. Geochemical studies indicate that copper has a relative correlation with silver.also based on studies of fluid inclusion, the depth of the ore, formation temperature and salinity are 100-200 meter, 100-140 °c and 5-15 WtNaCl%. Copper mineralization in the Saghari deposite has similarities in mineralogy, host rock, texture, structure and geometry with manto-type and volcanic red bed copper deposits.
Original Research Paper
Petrology
Sanaz Yajam; jalil Ghalamghash
Abstract
The easts Sanadaj- Galali plutons of the northern Sanandaj-Sirjan Zone, Zagros Orogeny, are composite, polyphase bodies that generated during subduction of Neotethys beneath the Eurasian plate. A-type magmatism in this area presents by Alkaline, high K, ferroan leucogranites. Despite having mineralogical ...
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The easts Sanadaj- Galali plutons of the northern Sanandaj-Sirjan Zone, Zagros Orogeny, are composite, polyphase bodies that generated during subduction of Neotethys beneath the Eurasian plate. A-type magmatism in this area presents by Alkaline, high K, ferroan leucogranites. Despite having mineralogical and isotopic similarities, these leucogranites show a clear division, based on the geochemical and SHRIMP zircon crystal dating results. Qalaylan leucogranite with the crystallization age of 159 ± 3Ma is A1-type. Other leucogranites are A2-type and crystalized about 20 million years later (140-149 Ma). In fact, mantle derived mafic magma, as heat source, caused partial melting of heterogeneous pre-fertilized Sanadaj-Sirjan basement and creates Qalaylan leucogranites. Younger leucogranites are A2-type and present different evolution path. These rocks generate in a post collisional setting as a result of partial melting of heterogeneous pre-fertilized Sanadaj-Sirjan basement, about 20 Ma later. In post collisional setting, asthenosphere upwelling do to the slab roll back or slab steepening could be a heat source of crust melting and generates the younger leucogranites.
Original Research Paper
Geological Environment and Engineering
Abbas Fallah; Soroush Modabberi; Alireza Sayyareh; amir ali Tabakh shabani
Abstract
For study the effects of traffic and urban pollution on heavy metals concentration, 40 soil samples were collected in green areas of Karaj city with different uses and 5 samples as geochemical background were collected from unpolluted areas and margins of the city. The samples after preparation were ...
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For study the effects of traffic and urban pollution on heavy metals concentration, 40 soil samples were collected in green areas of Karaj city with different uses and 5 samples as geochemical background were collected from unpolluted areas and margins of the city. The samples after preparation were analyzed by ICP-OES method. Statistical data were analyzed by SPSS (version 21) software. Relation of elements and pollution indexes determined for noticeable elements in karaj city. The Statistical analysis indicate that the distribution of metal such as: Cd,Cr,Cu,Ni and Zn in soil of Karaj city are similar to each other and often in the central part of Karaj city( Jahanshaher garden , Family park) Compared to other regions is more. Heavy metals in farmland soil are lower than other lands (garden, park). These findings are matching with the results reported by other researchers (from other regions of world). As, S and Zn have different distribution than other listed heavy metals. The Mean value of Zn, P, Ni, Cu, Cr, Co and Cd in the central part of Karaj city is more than other regions. PI value in the Karaj city soil for various heavy metals are respectively as: As>S>P>Zn>Pb>Cu>Ni, Cr>Cd The heavy metals pollution index for Karaj is 1.75, which is one of the moderate pollution soils.
Original Research Paper
Petrology
Marzieh Asadi-Avargane; Mehdi Rezaei-Kahkhaei; Habibollah Ghasemi
Abstract
The Qarah Chay Neogene caldera is located at 30 km SE Quchan in the Binalud Zone. The volcanic rocks of the caldera are mainly dacite in composition and composed of plagioclase and amphibole. The rocks present a variety of porphyry, microlitic porphyry, sieve, trachytic and glomeroporphyritic textures. ...
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The Qarah Chay Neogene caldera is located at 30 km SE Quchan in the Binalud Zone. The volcanic rocks of the caldera are mainly dacite in composition and composed of plagioclase and amphibole. The rocks present a variety of porphyry, microlitic porphyry, sieve, trachytic and glomeroporphyritic textures. Based on the spider diagrams normalized to chondrite and primitive mantle, the study rocks show enrichments in Large Ion Lithophile Elements (LILEs) and depletion in Heavy Rare Earth Elements (HREEs) and High Field Strength Elements (HFSEs). Their’s calc-alkaline affinity and the obvious negative HFSE anomalies (such as Ti, Nb and P), and positive Pb anomaly are similar to those magmas related to active continental margin. Moreover, their high concentrations of Sr, Sr/Y, Na2O/K2O, and low concentrations of K and MgO are the same as high silica adakites. Considering the above points, the parental magma(s) of the Qarah Chay Caldera formed from the partial melting of eclogite during the subduction of oceanic lithosphere of Sabzevar under the southern edge of the eastern Alborz zone in Neogene. It seems that the major Quchan and Dareh Gaz strike slip faults played a main role for the caldera formation.
Original Research Paper
Geophysics
zahra hajeb; zahra mousavi; zohreh masoumi; Abolfazl Rezaei
Abstract
The arid and semi-arid climate with a low rainfall along with the population growth has been lead to overexertion from groundwater resources over recent two decades in Iran. This over-extraction has been led to the significant groundwater depletion and water level decline in most parts of Iran as well ...
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The arid and semi-arid climate with a low rainfall along with the population growth has been lead to overexertion from groundwater resources over recent two decades in Iran. This over-extraction has been led to the significant groundwater depletion and water level decline in most parts of Iran as well as to the significant land subsidence in many aquifers throughout Iran. In this study, we investigated the subsidence occurred over the Jafarabad and Qanavat in Qom plain using the radar interferometry technique in conjunction with hydrogeological measurements. We used ENVISAT ASAR images from 2003 to 2010, in descending orbits to produce interferograms. Once all interferograms are corrected from topographic and flatten phase, we obtain the mean velocity map of the Qom plain region based on SBAS time series analysis method. The mean velocity map reveals 35 and 28 mm/yr of going away deformation in the line of sight direction in Jafarabad plain and Qanvat plain, respectively. Zoning map of subsidence resulted from the InSAR analysis in conjunction with the water level measurements and the thickness of fine-grained sediments (clay and silt) across the aquifers indicated that the maximum subsidence occurred in the places that not only have a higher water level decline but also have the thicker thicknesses of fine-grained sediments. This work clearly highlights the influences of mismanagement of water resources and over-extraction of groundwater in the arid areas.
Original Research Paper
Economic Geology
Fardin mousivand; Fayeq Hashemi; Mehdi Rezaei-Kahkhaei; Amir Pakizeh
Abstract
The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering ...
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The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering of the host rocks. Ore structures and textures are dominated by semi-massive to brecciated, banded and vein-veinlets. Main primary minerals are galena, pyrite and chalcopyrite, and secondary minerals are dominated by covelline, goethite and hematite. Gangue minerals are epidote, chlorite, sericite, clay minerals, quartz, calcite and barite. Wall rock alterations are dominated by epidote-chlorite and sericitic. The rare earth element (REE) pattern of ores is not similar to that of volcanic rocks in the footwall and hangingwall that is concordant with sub-seafloor replacement process for ore formation. Also Ce showed negative anomaly that can be attributed to Ce in the seawater. Also based on structural, stratigraphic, petrographic, textures, mineralogical, alteration and geochemical studies, it is inferred that the Pb (Ag) mineralization in the Darreh Amrood area occurred as bimodal felsic- or Kuroko-type volcanogenic massive sulfide (VMS) mineralization, and formed as sub-seafloor replacement. It should be noted that the Darreh Amrood deposit is the first recognition of base metal-rich and poor barite VMS mineralization in the UDMA.
Original Research Paper
Economic Geology
Mostafa Esmaeili-Vardanjani; Mostafa Nazeri; Gholamreza Asgari
Abstract
Gilsonite mineralization in Shak Meydan zone as the most prone zone of Iranian gilsonite mineralization was predominantly hosted by the anidrite part of Asmari Formation (Kalhor member) and Gachsaran Formation. To find the prospect areas of gilsonite mineralization in ShakMeydan zone, the zone was divided ...
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Gilsonite mineralization in Shak Meydan zone as the most prone zone of Iranian gilsonite mineralization was predominantly hosted by the anidrite part of Asmari Formation (Kalhor member) and Gachsaran Formation. To find the prospect areas of gilsonite mineralization in ShakMeydan zone, the zone was divided into three sub zones in which exploration studies were conducted. We first tried to determine lithologic units using remote sensing processing and to separate rock units using image processing technology. Next, we plotted a 3D structural modeling of the study zone in order to increase the depth precision and to determine the stratigraphic sequence and stratigraphy-structural adaptation. Finally, we detected structural controllers including faults and existing breaks in each sub zone and circular structures prone to translocate minerals. In the sequel, we assigned appropriate weights to applied information layers including geological, tectonic, mineral information and the results of remote sensing studies using analytical hierarchy process (AHP) based on Knowledgeable information and field studies to synthesized the exploratory data in order to introduce the prospect areas with exploration priority.
Original Research Paper
Economic Geology
A. R. Zarasvandi; Fatemeh Davoodian Ranjbar; Mohsen Rezaei; M. Tashi; Houshang Pourkaseb
Abstract
Sarkuh porphyry copper deposit is located 180 km west of Kerman province, 6 km southwest of Sarcheshmeh porphyry copper mine in the northeast of Pariz city. Considering geological divisions, it is a part of Urumieh-Dokhtar magmatic arc. The exposed rocks in this area are mainly composed of volcanic units, ...
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Sarkuh porphyry copper deposit is located 180 km west of Kerman province, 6 km southwest of Sarcheshmeh porphyry copper mine in the northeast of Pariz city. Considering geological divisions, it is a part of Urumieh-Dokhtar magmatic arc. The exposed rocks in this area are mainly composed of volcanic units, tuffs, andesite and basaltic andesite. Also intrusive units include granite to granodiorite, and to a lesser extend quartz diorite rocks. Major alterations of the deposit include potassic, phyllic, argillic and propylitic, as well as intermediate alterations such as potassic - argillic and potassic - phyllic. The purpose of this research is to study the chemical features of biotite and chlorite in order to investigate the physicochemical attributes of porphyry system during magmatic to hydrothermal transition in the patassic alteration. Based on the temperatures of reequilibrated biotite, at the time of magmatic to hydrothermal transition, the temperature ranged from 343 to 397°C. Also high magnesium nature of biotites, and their plotting in the boundary of magnetite-hematite (HM) and nickel-nickel oxide (NNO) buffering lines, as well as presence of magnetite with hematite rims indicate previlling of the high oxygen fugacity during potassic alteration.
Original Research Paper
Economic Geology
SHAHRAM RAHMANI; Hasan Zamanian; reza Zarei Sahamieh
Abstract
Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran ...
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Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran type. The intrusive rocks are enriched in LILE, LREE and depleted from HFSE, MREE and HREE and Y. A listric-shaped REE pattern and average La/Yb ratios of host rock indicates higher water content and fO2 in the magma and hornblende fractionation. Their relatively low to moderate ISr values (0.7047–0.7051), positive εNd (t = 36 Ma) values (0.39–2.1) and TDM ages of 0.69 to 1.06 Ga, with Pb isotopic ratios of (206Pb/204Pb) i = 18.49–18.68, (207Pb/204Pb) i = 15.58–15.61 and (208Pb/204Pb) i = 38.33–38.77. Based on textural evidence (coarse amphibole crystals), geochemical data (major, trace and Rare earth elements) and isotopic contents of Pb, Sr-Nd, it is suggested that these rocks correspond to geochemical and isotopic compositions of the host rocks of porphyry and epithermal deposits in the Urmia Dokhtar zone of West Alborz-Azerbaijan (Arasbaran) and Eastern Pontides epithermal deposits, Turkey.
Original Research Paper
Petrology
Sima Peighambari; Mahdieh Mohammadi; Hamid Ahmadipour
Abstract
Podiform chromitite bodies of various sizes associated with dunite envelopes found at several localities in the Ab-bid ultramafic massif in the southeast of the outer Zagros ophiolite belt. The chromitites occur as layered and lenticular bodies and veins which show different magmatic textures such as ...
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Podiform chromitite bodies of various sizes associated with dunite envelopes found at several localities in the Ab-bid ultramafic massif in the southeast of the outer Zagros ophiolite belt. The chromitites occur as layered and lenticular bodies and veins which show different magmatic textures such as massive, disseminated, and banded features. The Ab-Bid chromitites display a variation in Cr# from 65.36 to 58.43. The Al2O3 and TiO2 contents of chromites range from 18.03% to 22.58 % and 0.20 % to 0.39 %, respectively. The Al2O3, TiO2 and FeO/MgO values, calculated for parental melts of Ab-Bid chromitites, are within the range of melts which are similar to tholeiitic melts. Structural features such as sharp contacts between chromitites and their dunite envelope with host harzburgites, no correlation between chromitite size and dunite thickness, and various textures may be related to magmatic-metasomatic processes through interconnected dunitic channels. The mineralogical and chemical compositions of the chromitites as well as calculated parental melt compositions of Ab-Bid chromitites are consistent with the idea that the Ab-Bid massif was part of mantle section of an ophiolite from a suprasubduction zone. Harzburgites was influenced by hydrous partial melts; variable melt/rock interaction caused the formation of dunitic channels and allowed the chromitite parental melt to percolate through them. Middle partial melting degrees and other mineral chemistry of chromites could be representative of back-arc oceanic spreading environments. Therefore, Ab-Bid harzburgites are parts of mantle wedge above the subducting Neo-Tethys oceanic plate which is under a probably Upper Triassic-Cretaceous back-arc spreading centre.
