Original Research Paper
Volume 24, Issue 96 , September 2015
Original Research Paper
Volume 24, Issue 96 , September 2015, Pages 1-2
Original Research Paper
Volume 24, Issue 96 , September 2015, Pages 2-3
Original Research Paper
J Rasouli; M Ghorbani; V Ahadnejad
Abstract
Jebale-Barez granitoid complex is composed of intrusive bodyes included Mijan, Dareh hamzeh, Kerver and Hishin and is located In the southeastern province of Kerman on the lengths of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'.The petrologic composition ...
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Jebale-Barez granitoid complex is composed of intrusive bodyes included Mijan, Dareh hamzeh, Kerver and Hishin and is located In the southeastern province of Kerman on the lengths of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'.The petrologic composition in intrusive bodyes composed of granodiorite, quartzdiorite, granite and alkali-granite. The geochemical variation diagrams of major oxides, the continuous spectrum of rock compositions has been carried out which indicates the crystallization of magmatic differentiation and extensive appendices. The magma nature of these rocks is sub-alkaline-calc-alkaline, which in SiO2-K2O plot they fall into calc-alkaline series with high potassium. Field observations, petrographic and geochemical studies suggest that the rocks in this area have granitoides I type. Studying the geochemical diagrams of the rocks in the studied area indicates that these rocks have been formed in active continental margin tectononic setting. Most of the volcanic arc granites (VAG) are of "pre-collision" and "syn- collision" types. Three magmatic phases occurred in oligomiocene in this area. The first phase of magmatism in this area composed of the quartzdiorite and diorite that makes the main body of Jebale-Barez granitoid complex. Porphyry bodies will penetrate into the main body, after a short period of magmatic fractionation inside the nest of magma. Petrographic composition of the second phase is mainly diorite to tonalite. Oligo-Miocene magmatic final phase (Phase III) occurs in the region after a short time that the lithological composition of the granite to alkali granite. The third group of rocks in the study area from the main body mother came from magma fractionation. based on the location of Urmia-Dokhtar magmatic belt seems the rocks of this region there came to subducted oceanic crust Neotethyan beneath continental crust of central Iran.
Original Research Paper
A Mehrabi; M Dastanpour; Sh Radfar; M.R Vaziri; R Derakhshani
Abstract
In the Zagros structural zone of Iran, there is a broad range of emergent salt domes, a unique morphology in the world that is developed in tectonic environment. In the Zagros fold-thrust belt, emergent salt domes exhibit the linear patterns. Such trends indicate their relation to the linear structural ...
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In the Zagros structural zone of Iran, there is a broad range of emergent salt domes, a unique morphology in the world that is developed in tectonic environment. In the Zagros fold-thrust belt, emergent salt domes exhibit the linear patterns. Such trends indicate their relation to the linear structural features which are observable by Landsat imagery. Detection of fault lineaments and their spatial relationship with salt dome locations have been the matter of this study on statistically viewpoints. Based on the remote sensing analysis, horizontal displacements of parts of folded structures and distribution of Hormoz series salt domes, 33 fault lineaments were detected. A statistical method called the weight of evidence modeling is used for determination of the relationship between salt domes places and fault lineaments trends. For this purpose, the fault lineaments map and the center of salt domes map are converted to the raster one and buffers extracted around the fault lineaments; then, the spatial relationship between the salt domes and fault lineaments are quantified using weights of evidence method. The salt domes are associated spatially with the fault lineaments within distances of 1 km in horizon. Weights of evidence method show that the fault lineaments could be the most important foci for emplacement of salt domes in the study area.
Original Research Paper
E Moosavi; M Mohajjel
Abstract
Two main metamorphic events have occurred within Muteh- Golpayegan metamorphic core complexes (including eastern and western complexes) in the Sanandaj-Sirjan zone. Some grain-scale deformations were also happened in relation to these metamorphisms which have produced various deformation microstructures. ...
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Two main metamorphic events have occurred within Muteh- Golpayegan metamorphic core complexes (including eastern and western complexes) in the Sanandaj-Sirjan zone. Some grain-scale deformations were also happened in relation to these metamorphisms which have produced various deformation microstructures. Microfaults are among the microstructures that were formed during brittle conditions. Bulging recrystallization of quartz and rarely feldspar grains, and bookshelf structure of fragmented feldspar porphyroclasts indicate various deformation and formation of shear zones under low-temperature conditions in the eastern complex. Polygonal granoblastic texture of polycrystalline quartz porphyroclasts documents post-mylonitization annealing at medium- grade conditions in shear zones of eastern complex. Chessboard pattern quartz subgrains propose high-grade metamorphic conditions during the first deformation. However, their undulatory extinction reveals low-grade conditions for the second deformation. Polygonal granoblastic texture of chevron folded feldspar grains also accurately supports these conditions during the two mentioned deformations. In general, considering deformation microstructures and conditions, three stages of recrystallization are respectively recognizable in the Muteh-Golpayegan metamorphic complexes including: 1- high-grade static recrystallization subsequent to early metamorphic event, 2- dynamic recrystallization and related mylonitization under low-grade to locally medium-grade conditions, 3-post-mylonitization static recrystallization in medium-grade conditions. The north Golpayegan intrusive bodies can be considered as the heat source for annealing in the western complex but the cause of annealing is not evident in the eastern complex.
Original Research Paper
M.R Hosseinzadeh; S Maghfouri; M Moayyed; M Lotfehnia; B Hajalilou
Abstract
The studied area is located in Tarom metallogenic zone (NW of Iran). This area illustrate widespread hydrothermal alteration and disseminated and vein-veinlet type copper, lead and zinc mineralization.Injection of qm Intrusive body into Eocene volcano clastic complex (Karaj Formation) along linear Faults ...
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The studied area is located in Tarom metallogenic zone (NW of Iran). This area illustrate widespread hydrothermal alteration and disseminated and vein-veinlet type copper, lead and zinc mineralization.Injection of qm Intrusive body into Eocene volcano clastic complex (Karaj Formation) along linear Faults caused intense hydrothermal alterations such as phyllic, argillic, propylitic and silicification. The major minerals of this rock are plagioclase, biotite, pyroxene, hornblende, alkali-feldespar, quartz with Lesser amount apatite, zircon, opaq minerals, rutile and sphene. Based on microscopic and geochemical assessments this rock is quartz- monzonite, tonalite, quartz- monzodiorite, and has calk-alkaline to shoshonitic and meta-aluminous character. This Pluton belongs to a volcanic arcs regime. The hydrothermal activities of penetrate intrusion causes the creation of two system vein and veinlet: ore bearing quartz vein- veinlet’s and non-ore bearing carbonate vein- veinlets. The mineralization in loubin- zardeh occured in quartz vein- veinlet along faults created via the intrusion of the intrusive. The main mineralizations of area are oxide (illmenite), sulfide (pyrite, Chalcopyrite, galena, sphalerite), sulfate (barite) and the supergene minerals are oxides and hydroxide, (hematite, goetite), sulfide (covelite), sulfate (anglesite) and carbonate (malachite and azourite). The most important characteristics of mineralization at the Lubin- Zardeh area such as tectonic setting, host rocks, mineralogy, metal content as well as wall rock alterations, and to compare these characteristics with the basic features of Epithermal deposits, the polymetal vein- veinlet mineralization in Lubin- Zardeh placed in the Epithermal category.
Original Research Paper
A Mohebi; A Hezarkhani; M Behzadi; H Mirnejad; H Taghi Zadeh
Abstract
Bondar Hanza porphyry copper deposit occurs 150 km southeast of Kerman, in southern part of the Urmia-Dokhtar zone and in Dehaj-Sardoiyeh zone. This ore deposit has formed in diorite to granodiorite rocks. The present paper deals with the study of fluid inclusion on quartz and hornblende samples as well ...
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Bondar Hanza porphyry copper deposit occurs 150 km southeast of Kerman, in southern part of the Urmia-Dokhtar zone and in Dehaj-Sardoiyeh zone. This ore deposit has formed in diorite to granodiorite rocks. The present paper deals with the study of fluid inclusion on quartz and hornblende samples as well as the measurement of isotopic ratio of oxygen and hydrogen with the aim to recognize characterization of hydrothermal fluids effective in mineralization. The studied veinlets are divided into five groups. Veinlet I: fluid of high pressure (>300 MPa) and medium to high temperature (250°C-300°C) with salinity of 38-45 Wt%NaCl that includes molybdenum mineralization. This veinlet contains halite and anhydrite and has resulted in potassic and sodic-calcic mineralization in deeper parts of the ore deposit. Veinlet II: high pressure (>300 MPa), high salinity (33-47 Wt%NaCl) and high temperature (250°C-420°C), containing copper and molybdenum mineralization as well as potassic alteration. Veinlet III: high salinity (40-56 Wt%NaCl), high pressure (>300 MPa) and high temperature (200°C-500°C), containing copper mineralization. Veinlet IV: medium to low salinity (6-7 Wt%NaCl), medium temperature (approximately 170°C), low pressure (0/7-0/8 MPa), containing no mineralization. The study performed indicate that the boiling occurred in the initial magma, as a result of pressure and temperature changes and mixing with meteoric waters, caused copper and molybdenum mineralization. Results obtained from oxygen and hydrogen isotopic analysis in quartz show δ18O to vary from 3.9 to 6.3 per mil. Considering its formation temperature and based on thermometric study (130-400°C), the amount of δ18o in mineralizing fluid is from 5.26 to 6.19 per mil, being indicative of magmatic origin of mineralization fluids like the other porphyry copper deposits of Iran and the world. While results of hydrogen analysis existed in fluid inclusions of quartz mineral illustrate a range between -88 to -90 per mil, being indicative of a decrease in the amount of mineralizing fluid deuterium. These values are traceable to the effect of meteoric waters, given the propylithic and sodic alterations accompanied with potassic alteration in mentioned veinlet.
Original Research Paper
M Behyari; M Mohajjel; M Rezaeian; M Moayyed
Abstract
Misho Complex in NW Iran has a remarkable unique high topography surrounded by well known faults, where Precambrian basement rocks were uplifted and exposed. Structural data indicate that the exhumation of the Misho Complex was result of displacements along the North Misho, South Misho and Tasouj faults. ...
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Misho Complex in NW Iran has a remarkable unique high topography surrounded by well known faults, where Precambrian basement rocks were uplifted and exposed. Structural data indicate that the exhumation of the Misho Complex was result of displacements along the North Misho, South Misho and Tasouj faults. Study of structural and thermochronometery and combination of their results show that uplift initiation time was not unique in this Complex. Analysis of 10 AFT samples clear that the western Misho Complex has the high amount of uplifting during early Palaeocene (72.7 10.6) mid Miocene (50.3-3.4) time. But uplifting in central and eastern parts of the Misho Complex was starting later in mid-Miocene (22.5 3.4). Difference in uplifting time in various parts of Misho Complex resulted in variety of basement uplifting and exhumation in different parts of the Misho Mountains. Interpretation of minimum and maximum topography homogenised samples shows that the rate of uplifting was more than that in the western part of the Misho Complex. It is concluded that, displacements variations along the surrounded faults and rotation of existing blocks resulted in variation of the uplifting and exhumation amount in the area.
Original Research Paper
M Lotfi; M Hekmatian; A.A Shabani; M.A Mokhtari
Abstract
Oras-kuh lead-zinc deposit is located at about 79 km north-east of Semnan city. This deposit is considered as stratabound and occurs in the upper part of the Triassic dolomitic limestone of the Elika formation. Oras-kuh structure includes a northeast - southwest trending normal anticline and follows ...
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Oras-kuh lead-zinc deposit is located at about 79 km north-east of Semnan city. This deposit is considered as stratabound and occurs in the upper part of the Triassic dolomitic limestone of the Elika formation. Oras-kuh structure includes a northeast - southwest trending normal anticline and follows the general trend of the eastern Alborz. Folding in the area has generatedthree sets of jointsincludingjoints trending parallel to the direction of anticline axis, extensional joints perpendicular to anticline axis and the conjugate joint systems. The first two setsof the joints host vein form mineralization. In addition, breccia and karst filling mineralization can be detected. Major minerals are galena, sphalerite and pyrite that altered to secondary minerals such as cerussite, goethite, hydrohetarolite and rosasite under the supergene processes. Gangue minerals are dolomite, calcite, barite, quartz, and small amounts of fluorite. The majority of the temperature data are between 298 to 323°C based on the fluid inclusion geothermometry of calcite and barite minerals. The relatively high temperatures of fluid inclusions are attributed most likely to a concealed deep intrusion in the crust inferred byairborne geomagnetic survey. Fluid salinities show a wide range from 0.6 to 15wt% equivalent weight of NaCl formed through mixing of basinal brines with meteoritic water. In general based on the present evidences, Oras-kuh lead-zinc deposit can be comparable with MVT deposits that its primary mineralogy and elemental ratios have been changed through secondary supergene processes.
Original Research Paper
M Afarin; M Boomeri; A Mahboubi; M Gorgij; M.A Hamzeh
Abstract
In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis ...
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In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis using XRF and ICP AES methods. Positive sorting and skewness (with the frequency of fine grain particles) of samples indicate deposition in a low energy environment. Plotting geochemical data of major elements from Late Miocene- Pleistocene age 10 mudstone and sandstone samples in east coasts of Chabahar in Makran zone, on siliciclastic rocks classification diagrams, showed that the sandstones are wacky and Mudstones are shale. The mean calculated chemical indexes of alteration (CIA) and weathering (CIW) for siliciclastic sediments, confirm low level weathering of source rocks of this sediments. The average index of combinational variety (ICV) for the studied sediments was 1.57, which indicates that these deposits have a moderate chemical maturity and are derived from the first cycle of sediments. Distribution pattern of rare earth elements on spider diagrams shows the enrichment of light rare earth elements (LRRE) relative to heavy rare earth elements (HRRE) in the rocks. High ratios of LILE/HFSE and LRRE/HRRE in the rock samples and similarity of their chemical composition with subduction zone facies, indicates that siliciclastics of Chabahar coasts have formed in a subduction zone. The diagrams of tectonic setting associated with patterns of multivariate charts also shows that the studied rocks have been developed in an active continental margin.
Original Research Paper
M Refoseh; A Shaker Ardakani; H Ranjbar
Abstract
Volcanic, sub-volcanic (dyke) and pyroclastic (agglomerate and tuff) rocks of Eocene age are located in the Kalmard block in the north and northeast of Kerman City. Petrographically, the lavas are basalt, andesite, rhyodacite and rhyolite, whereas the dykes and pyroclastic rocks are andesite and crystal ...
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Volcanic, sub-volcanic (dyke) and pyroclastic (agglomerate and tuff) rocks of Eocene age are located in the Kalmard block in the north and northeast of Kerman City. Petrographically, the lavas are basalt, andesite, rhyodacite and rhyolite, whereas the dykes and pyroclastic rocks are andesite and crystal tuff in composition respectively. The porphyritic, microlitic-porphyritic and trachytic are the main textures and mineralogically consist of plagioclase± quartz± K-feldspar ± biotite± amphibole± clinopyroxene± olivine+ opaque minerals. Plagioclases show evidences of disequilibrium textures such as sieve texture, resorption and zoning; whereas quartzes have resorbed margins, and amphiboles and biotites are only slightly opacitized. These textures can be resulted from magma mingling, PH2O variations, and decompression with minor loss of temperature during magmatic ascent. Geochemical studies revealed that the volcanic rocks belong to a sub-alkaline magmatic series with calc-alkaline nature. Furthermore, acidic volcanic rocks are metaluminous to peraluminous and show characteristics of I-type granitoids. The trace element discrimination diagrams along with chondrite-normalized rare earth element patterns show that the igneous rocks formed in an active continental arc environment.
Original Research Paper
A.A Morshedy; H Memarian
Abstract
Various interpolation and estimation tools are used to spatially model a regional variable across an area or site. This paper presents a new interpolation method, using the progressive radial basis function network and taking into account the spatial coordinates of the input data. The procedure starts ...
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Various interpolation and estimation tools are used to spatially model a regional variable across an area or site. This paper presents a new interpolation method, using the progressive radial basis function network and taking into account the spatial coordinates of the input data. The procedure starts with the study of the spatial structure and anisotropy of the data, to perform interpolation and determining the radiuses and rotation angles based on the directional variography. Next, the neighborhood radius and neighboring points of each node of hidden unit are determined, using the ellipsoidal anisotropy and the covariance matrix. Then, a shape factor is computed based on half the average distance of all the neighboring sample points. The progressive kernel matrix includes the corrected kernel functions and the coordinates of the nodes in the hidden units utilized to solve the weight matrix. The interpolation was finally performed at each point of regular network (unsampled points). The steps of this interpolation algorithm were evaluated by a synthetic data set, having an irregular 3D pattern. The Cross validation between actual and estimated values have a correlation coefficient of about 0.78 and the fitted line passing through the actual and estimated values is close to 45 degrees.
Original Research Paper
M Sheibi; M Pooralizadeh Moghadam
Abstract
Panj-Kuh granitoid intrusion with an area of 15 Km2 is intruded into the Eocene volcano-sedimentary sequence, in south-east of Damghan city. Syenite is the main composition of the pluton. It has converted to monzonite wherever subjected to sodic-calcic alteration. The presence of albite-scapolite veins ...
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Panj-Kuh granitoid intrusion with an area of 15 Km2 is intruded into the Eocene volcano-sedimentary sequence, in south-east of Damghan city. Syenite is the main composition of the pluton. It has converted to monzonite wherever subjected to sodic-calcic alteration. The presence of albite-scapolite veins (from mm to some hundred meters in width) are the main evidences of the Na-Ca alteration in the mentioned pluton. Present study investigates the result of magnetic fabric in the Panj-Kuh pluton and defines the emplacement mechanism according to the lineation and foliation patterns and microstructural observations. The pluton belongs to the ferromagnetic granites due to high mean bulk magnetic susceptibility (Km>400mSI) and presence of magnetite. The highest anisotropy values were observed in the regions with high deformation. High plunging lineation and foliations associated with negative value of shape parameter show the magma feeder zones. According to the present study, it seems that the pluton has two different types of fabric patterns. The first pattern belongs to the magmatic liniation and foliation that are arranged parallel to the long axis of the pluton with NE-SW trend. The second fabric is related to the regions that were subjected to Na-Ca alteration and cross cutting the first pattern as three parallel corridors. This fact is confirmed by magmatic to low temperature solid state microstructures as well. Compiling all data implies that the mentioned pluton was emplaced in a sinistral shear zone.
Original Research Paper
Kh Baharfirouzi; A Khakzad; H Nazari; M.H Emami
Abstract
The Azerbaijan plateau is distinguished by varied geomorphology and mineralization, both of which controlled by the dominant structural regime in the area, that is associated with the collision of the Arabian and Eurasian plates. Strike slip faults are the main structural features controlling the development ...
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The Azerbaijan plateau is distinguished by varied geomorphology and mineralization, both of which controlled by the dominant structural regime in the area, that is associated with the collision of the Arabian and Eurasian plates. Strike slip faults are the main structural features controlling the development of various compressive or extensional zones in Azerbaijan. The dominant faults are striking NW-SE and NE-SW and display right lateral and left lateral displacements, respectively. The vergence of vectors on two sides of faults in the fault conjunctions, control the dominant stress regime, geomorphology, emplacement of dikes, as well as the gold-bearing silica veins. The bent parts and steps between different tips of faults are other controllers of dominated tectonic regime and emplacement of granitic stocks and gold bearing silica veins. Because of change on the strike of Ahar-Sarab fault, an extensional regime prevailed in southwest of Sabalan and silica veins injected in this area, some of these veins are auriferous.
Original Research Paper
M Javid; H Memarian; S.M Mazhari; R Zorofi; B Tokhmechi; F Khoshbakht
Abstract
In the oilreservoirsof the ZagrosBasin, fractures play a major role in hydrocarbon migration and production. Borehole image log is a powerful tool to study and identify fractures around the wells. These logs provide critical information about orientation, depth and type of natural fractures. Since thereis ...
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In the oilreservoirsof the ZagrosBasin, fractures play a major role in hydrocarbon migration and production. Borehole image log is a powerful tool to study and identify fractures around the wells. These logs provide critical information about orientation, depth and type of natural fractures. Since thereis noaccuratealgorithmfor automaticidentification of fracture parametersonimage logs of the carbonatereservoirsin Iran, interpretation of theselogsisoftendone manually. This process may become erroneous if the interpreter is not sufficiently experienced. Aimed at automatic detecting of fractures in image logs, this paper presents a new implemented method, which is based upon image processingandoptimization techniques,as well as Artificial Bee Colony Algorithm. According to this approach, points related to fractures arefirst extracted from images using classification methods. Then, the Artificial Bee Colony Algorithmis used to determine the number, depth, dip and dip directionof fractureson extracted points. The proposed method is performed on FMS image log ofonewell located in an oilfield in southernIran. Results areshownindensity log, rose diagramandstereogramfor the identified fractures, and the obtained resultsshow efficiency of the proposedmethod.
Original Research Paper
M Joudaki; D Baghbani; S.A Aghanabati; B Soleimani; H Asilian; B Ariafar
Abstract
In order to biostratighraphy and to discover relationships between biozones of the Oligocene and lower Miocene strata in Zagros foreland basin, Zagros simply folded belt and High Zagros area, 10 stratigraphic sections along a transect from well "A" in Persian Gulf to Semirum section in High Zagros ...
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In order to biostratighraphy and to discover relationships between biozones of the Oligocene and lower Miocene strata in Zagros foreland basin, Zagros simply folded belt and High Zagros area, 10 stratigraphic sections along a transect from well "A" in Persian Gulf to Semirum section in High Zagros were investigated. The study of more than 1500 thin sections resulted in identification of 32 genera and 54 species of benthonic foraminifera belonging to nine genera and 15 species of planktonic foraminifera. The recorded assemblages led to establishment of six biozones ranging in age from Oligocene to Early Miocene. Biostratighraphic correlation yielded clarification of relationship between biozones and sedimentary trends and discontinuities of the Oligocene and lower Miocene in Zagros basin in the areas.
Original Research Paper
S Tabasi; A KamkarRouhani; M.M Khorasani
Abstract
Archie’s equation, which is the most fundamental equation for water saturation calculation,consists of three factors: Cementation factor (m), saturation exponent (n) and tortuosity (a). Cementation factor is a function of the shape of pores. Hence, the study of pore type is important in determining ...
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Archie’s equation, which is the most fundamental equation for water saturation calculation,consists of three factors: Cementation factor (m), saturation exponent (n) and tortuosity (a). Cementation factor is a function of the shape of pores. Hence, the study of pore type is important in determining the Archie’s coefficients. In order to achieve more precise and reliable results in Archie’s coefficient determination and then water saturation accurately, the rocks must be rated based on texture and porosity type, where the coefficients should be constrained for each class. In this paper, fractal method is used to rate the resistivity log data and calculate Archie’s coefficient in an exploration well of a hydrocarbon reservoir in southwest of Iran. The results show three different zones based on porosity type and texture of the rocks. Then the Genetic algorithm method is used to calculate the Archie’s coefficients in each of the zones separately. The results show that this method is able to consider the complex behavior of each of the coefficients in the calculations.
Original Research Paper
B Hajalilou; Z Karimzadeh; M Advai
Abstract
The properties and situation of copper mineralization in the Haj Alibay Kandi area determined by quartz vein fluid inclusion and geophysical explorations in this study. The most important rock units include Oligocene intrusive rocks with monzonite and quartzmonzonite compositions. These rocks belong ...
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The properties and situation of copper mineralization in the Haj Alibay Kandi area determined by quartz vein fluid inclusion and geophysical explorations in this study. The most important rock units include Oligocene intrusive rocks with monzonite and quartzmonzonite compositions. These rocks belong to calc-alkaline series and post orogenic and post collision regimes. The mineralization in this area was controlled by faults with NE-SW direction. These mineralizations are related to the Sheivar-Dagh and younger intrusives. Chalcopyrite, pyrite, chalcocite, digenite, covelite, malachite, bornite and iron oxides were determined by mineralographical studies. On the basis of geophysical explorations, the chargebility anomaly at the depth of 40 to 50 meters is related to the concentration of sulphide minerals. This anomaly is conforms with faulting system in the area. The salinity of ore bearing fluid is from 5 to 50 wt% of NaCl and the homogenization temperature is 200 to 2400c and higher, on the basis of fluid inclusions studies. Fluid inclusions data are conformable with porphyry and epithermal copper deposits. This study shows that the boiling of ore fluids occurred at the mineralization stage. The shape of copper mineralization is vein and veinlets in this area and similar to cordilleran vein type deposit which can be observed at the top of porphyry copper deposits . Therefore, the formation of porphyry copper deposit at the deep levels of this area is expected.
Original Research Paper
M.A Rajabzadeh; Z Ghorbani; M Jalalifard; M Mohammadzadeh
Abstract
Parvadeh coalfield with an area of 1200 km2 is one of the largest coalfields in East-Central Iran. The coal-bearing clastic rocks of the coalfield belong to Ghadir Member of the Upper Triassic Naiband Formation and could be classified as bituminous coal, containing low volatile, high ash and medium to ...
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Parvadeh coalfield with an area of 1200 km2 is one of the largest coalfields in East-Central Iran. The coal-bearing clastic rocks of the coalfield belong to Ghadir Member of the Upper Triassic Naiband Formation and could be classified as bituminous coal, containing low volatile, high ash and medium to high sulfur. Pyritic sulfur is the main form of sulfur in the Parvadeh coals. Quartz, illite, kaolinite, pyrite, and calcite/dolomite are the principal mineral phases. Enrichment in major elements and depletion in minor elements were observed in studied samples when compared with those of the earth crust. The element contents of coal-bearing layers are similar to those of the US and world coals except for Cd, Li, As and Zn. Based on the calculated enrichment factor, the elements As, Co and Cd are the most pollutants in Parvadeh area. Strong correlations among ash contents and Si, K and Al values indicate that the coal ash is mainly composed of aluminosilicates. Meanwhile, Cd, Co, As, Fe, and S show that Cd, Co, As participated in pyrite lattice. These results were confirmed by factor and cluster analyses. The calculated recovery index shows that Li, Mo, Pb and Cu are bounded to maceral and organic matter thus are enriched in the cleaned coals. The other minor metals, however, are present in mineral part of the coal and enriched in ash.
Original Research Paper
S.J Yousefi; A Aftabi; A Moradian
Abstract
Gossan occurs considerably around the Chahar Gonbad copper-gold mine. The mineralogy of gossan includes: hematite (Fe2O3), goethite (FeO(OH)), and limonite (Fe2O3.H2O) with colloform texture, as wewll as quartz, calcite and clay minerals. Enrichment factors include: Ag=1.08, As=1.19, Bi=70.12, Mn=4.11, ...
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Gossan occurs considerably around the Chahar Gonbad copper-gold mine. The mineralogy of gossan includes: hematite (Fe2O3), goethite (FeO(OH)), and limonite (Fe2O3.H2O) with colloform texture, as wewll as quartz, calcite and clay minerals. Enrichment factors include: Ag=1.08, As=1.19, Bi=70.12, Mn=4.11, Mo=2.37, Pb=1.51, Sb=1.7 and Fe=1.71 in comparison to the mineralized rocks. However, Cu=0.03, S=0.03 and Se=0.04 are strongly depleted; Zn= 0.94 is slightly depleted. Based on correlation coefficients, four droups can be distinguished. The first group includes Bi, Cu and Sb which have a good correlation with Fe and Mn. The reason for this correlation is probably the adsorption of Bi, Cu and Sb by iron and manganese hydroxides - oxides in gossans. The second group comprises of Pb and Ag which have a good correlation with Bi, Cu, and Sb, without any relationship with Fe and Mn. The third group elements are As, Mo and Zn which have no correlation with Fe and Mn, as they form insoluble complexes. The fourth group includes sulfur and selenium which formed by sulfide weathering, gossan formation and sulfate minerals. The correlation of Bi with Cu is caused by weathering of sulfide minerals and formation of gossan. Bi, Cu and Au enrichments in the gossan are 3123.94, 12.62 and 400 times the clarck values. All the elements in the gossans, in particular Bi could be considered as the possible exploration guides around Chahar Gonbad area.
Original Research Paper
M Poosti; M Fadaeian
Abstract
The study area is located in the Ardabil province and in the north of Meshkin shahr town. A large part of the areais formed of Eocene igneous rocks. These rocks include basaltic andesite, basalt, tephrite and occasionally analcimite. They are silica saturated or relatively saturated. ...
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The study area is located in the Ardabil province and in the north of Meshkin shahr town. A large part of the areais formed of Eocene igneous rocks. These rocks include basaltic andesite, basalt, tephrite and occasionally analcimite. They are silica saturated or relatively saturated. According to tectonomagmatic diagrams, the original setting of the parental magma was a volcanic arc and subduction zone. The negative anomalies of Nb, the high ratio of LILE/HFSE, the high mounts of Al2O3& P2O5, the low titanium contents, and the degree of partial melting of the metasomatized upper mantle, strengthens the subduction related processes for the formation of the primary magma (alkali olivine basalt). Petrographic evidences suggest that the primary magma is mixed with crustal materials. The chemical composition of rocks, according to geochemical diagrams, is shoshonitic. These rocks may have been formed by the subduction of the oceanic crust of Neoteties during the Mesozoic and early Cenozoic periods. Releasing fluids exerted from the subducting slab, metasomatism of the lithospheric mantle and subsequently the appropriate conditions for melting of the metasomatized mantle, all led to the formation of potassic magmatism and finally, generation of magma with a shoshonitic nature found its way to the surface under the influence of an extension phase and complex fault systems.
Original Research Paper
M Khalatbari Jafari; P Konani
Abstract
Lava-dome shallow massive bodies located right around Nodeh Engelab, SE Jogatay in Khorasan Razavi province, cutting Eocene volcanic rocks in northern part of Sabzevar ophiolitic belt, are covered by Pliocene-Quaternary deposits. The margin of bodies comprise of lavas of basalt, phyric andesite basalt, ...
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Lava-dome shallow massive bodies located right around Nodeh Engelab, SE Jogatay in Khorasan Razavi province, cutting Eocene volcanic rocks in northern part of Sabzevar ophiolitic belt, are covered by Pliocene-Quaternary deposits. The margin of bodies comprise of lavas of basalt, phyric andesite basalt, fluidal andesitic compositions but the medial parts and roof of masses composed of phyric andesite-trachy andesite, phyric-aphyric dacites and quartz monzodiorite. No impacts of pyroclastic deposits have been observed around these masses. The sieve texture, oscillatory zoning in plagioclase crystals could be attributed to disequilibrium in magma chamber. The lava from margins of shallow massive bodies has calc alkaline and the rocks from middle parts of the bodies show calc alkaline to high-K calc alkaline affinities. The spider diagrams of margin lavas have substantial compliance with those middle parts of bodies and show enrichment in Rb, Ba, Th, La, Sr, and clear depletion in Nb and Ti. Despite some samples plot in adakitic domain, but they do not display chemical characteristic of index adakites. It seems that the parental magma of the studied shallow intrusions produced from partial melting of mantle wedge which have different enrichment and probably influenced by the components released from subducted slab. The other scenario could be attributed to the partial melting of metamorphosed mafic rocks at the top of subducted slab.
Original Research Paper
M Roustaee; B Zamani; P Navabpour; M Moayyed
Abstract
Siah Cheshmeh- Khoy fault system is one of the principal faults in NW of Iran and that its right- lateral strike- slip activity has reported for different segments of this fault zone. Landsat 7 satellite images of the area, confirm the right- lateral strike- slip motion of this fault system by deflected ...
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Siah Cheshmeh- Khoy fault system is one of the principal faults in NW of Iran and that its right- lateral strike- slip activity has reported for different segments of this fault zone. Landsat 7 satellite images of the area, confirm the right- lateral strike- slip motion of this fault system by deflected drainage of large rivers, cutting and displacement of alluvial fans across the segments of the fault zone. The amount of alluvial fans displacement in -Dasht e zurabad- (along the segment of the Kamarkassan fault) was estimated nearly 1.8 km. In this research, the neotectonics and mechanism of the Siah Cheshmeh- Khoy fault zone has been studied by Inversion method, based on the combination of focal mechanisms of earthquakes and different shear- fault planes. In this paper, we utilized all of the focal mechanism solutions of earthquakes existent in this area. Besides, the data measured conclude shear planes whit slickenside and the measured fault planes across the Siah Cheshmeh- Khoy fault zone. These data were gaged in 7 sites and 45 shear planes with slickenside. Initially the main axis were obtained in all sites by Inversion method; then by combination of focal mechanisms of earthquakes and the measured data, the stress state of this region was evaluated. The results obtained of this analysis indicate strike- slip stress with NNW-SSE (N162°) direction of compression component and ESE-WNW (N255°)direction of extension component in this area. It can be stated that the mentioned stress regime was the main factors controlling the recent kinematic movements of faults and strong earthquakes in the region. Also the right- lateral strike- slip motion of the Siah Cheshmeh- Khoy fault segments are affected by this stress (under the influence of this stress). The results of this research are compatible with the results of the geodetic studies and the GPS measurements in the region that were done by other researches.
Original Research Paper
H Mohammaddoost; M Ghaderi; N Rashidnejad-Omran
Abstract
Qamsar cobalt deposit is located 26 km south of Kashan, in the middle part of Urumieh-Dokhtar magmatic arc. Exposed rock units in the area include Eocene volcanics, Qom Formation marine sediments and plutonic bodies. The intrusive bodies have quartz-diorite to granodiorite composition as well as porphyry ...
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Qamsar cobalt deposit is located 26 km south of Kashan, in the middle part of Urumieh-Dokhtar magmatic arc. Exposed rock units in the area include Eocene volcanics, Qom Formation marine sediments and plutonic bodies. The intrusive bodies have quartz-diorite to granodiorite composition as well as porphyry microdiorite. Intruding bodies into the Eocene volcanics and Qom Formation units caused recrystallization and metamorphism and formed assemblages of skarn minerals such as garnet, pyroxene, epidote, tremolite and actinolite. Mineralization occurred as endo-skarn and exo-skarn in massive, vein, brecciated, open space filling and diffusion forms. Magnetite is the main ore mineral and is accompanied by cobaltite, chalcopyrite and pyrite. Fluid inclusion microthermometry studies were performed on prograde stage garnet and pyroxene and retrograde stage quartz. Microthermometry studies show homogenization temperatures from 400 to more than 600°C and from 180 to 200°C as well as salinities between 12 and 20% and between 5.8 and 11.9% wt NaCl equiv. for prograde and retrograde phases, respectively. Isotopic thermometry on pyrite-chalcopyrite pair minerals gives 241 to 528°C and that for quartz-magnetite pair minerals gives 441 to 549 °C. Sulfur and oxygen isotopic ratios offer magmatic origin which mixed with basinal fluid for this mineralization.
Original Research Paper
Z Bikdeli; M Ebrahimi; Gh Nabatian; M.A.A Nabatian
Abstract
Chehrabad Cu deposit is located in the Zanjan province and in the northwest corner of Central Iran. Rock units exposed in this area belong to the Cenozoic era (especially Miocene period) and include the Lower Red Formation, Qom Formation, Upper Red Formation and Quaternary deposits. In the study area, ...
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Chehrabad Cu deposit is located in the Zanjan province and in the northwest corner of Central Iran. Rock units exposed in this area belong to the Cenozoic era (especially Miocene period) and include the Lower Red Formation, Qom Formation, Upper Red Formation and Quaternary deposits. In the study area, the Upper Red Formation which hosts the mineralization consists of alternating beds of marl, siltstone, oxidized red sandstone and light gray sandstone. Mineralization has occurred within the gray sandstones of bleached zone containing organic materials. In Chehrabad, copper deposit mineralization has been recognized in five horizons. Each horizon is composed of three zones including reduced zone with mineralization, bleached zone and oxidized red zone. The dominant texture in the Chehrabad Cu deposit is replacement texture which is accompanied with other textures such as disseminated, solution seams, lens like and interparticle cement texture. Lithology (sandstone host rock), sulfide mineralogy (e.g. pyrite, chalcocite, bornite and chalcopyrite), structure and texture, stratigraphy as well as factors controlling the mineralization (presence of plant remains performing as environment reductant and also the permeability in the host rock) suggest that this deposit is similar to the red-bed type sedimentary Cu deposits which is formed during the early to late diagenesis.
Chehrabad Cu deposit is located in the Zanjan province and in the northwest corner of Central Iran. Rock units exposed in this area belong to the Cenozoic era (especially Miocene period) and include the Lower Red Formation, Qom Formation, Upper Red Formation and Quaternary deposits. In the study area, the Upper Red Formation which hosts the mineralization consists of alternating beds of marl, siltstone, oxidized red sandstone and light gray sandstone. Mineralization has occurred within the gray sandstones of bleached zone containing organic materials. In Chehrabad, copper deposit mineralization has been recognized in five horizons. Each horizon is composed of three zones including reduced zone with mineralization, bleached zone and oxidized red zone. The dominant texture in the Chehrabad Cu deposit is replacement texture which is accompanied with other textures such as disseminated, solution seams, lens like and interparticle cement texture. Lithology (sandstone host rock), sulfide mineralogy (e.g. pyrite, chalcocite, bornite and chalcopyrite), structure and texture, stratigraphy as well as factors controlling the mineralization (presence of plant remains performing as environment reductant and also the permeability in the host rock) suggest that this deposit is similar to the red-bed type sedimentary Cu deposits which is formed during the early to late diagenesis.
Original Research Paper
H Ghasemi; Z Kazemi; SH Salehian
Abstract
On the basis of stratigraphical studies, parental rocks of the Gorgan schists have same petrological features and fossil contents as the Ghelli formation in the eastern Alborz Zone and despite to the previous theories, these schists are not Precambrian in age. Also, the mafic igneous rocks of these two ...
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On the basis of stratigraphical studies, parental rocks of the Gorgan schists have same petrological features and fossil contents as the Ghelli formation in the eastern Alborz Zone and despite to the previous theories, these schists are not Precambrian in age. Also, the mafic igneous rocks of these two rock units have considerable petrological and geochemical similarities. These mafic igneous rocks include basalt, trachybasalt and basaltic trachyandesite in association with microgabroic sills, dykes and small intrusions. Investigations on, and comparison of their petrological and geochemical features, indicate similarities in age, petrology, magma sources, geochemistry and tectonic setting. It seems that the parental rock of the Gorgan schists and the rocks forming the Ghelli formation were sedimentary and igneous rocks, deposited during the initial stages of extensional movements and rifting of the Paleotethys ocean during Ordovician in the eastern Alborz. However the, parental rocks of the Gorgan schists were metamorphosed in the greenschist facies in middle-upper Triassic (early Cimmerian orogeny), due to vicinity to the oceanic trench of the Paleotethys subduction zone. Geochemical features of the igneous rocks in these two units indicate 12-16% partial melting of an enriched garnet lherzolite mantle source (such as the Oceanic Island Basalt source) for generation of the original magma in the garnet peridotite stability field at 100-110 Km depth..
Original Research Paper
R Ferdowsi; A.A Calagari; M.R Hosseinzadeh; K Siahcheshm
Abstract
Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry ...
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Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry sequence of limestone, limy sandstone and marl (Paleocene-Eocene). Intrusion of the stock into the sedimentary rocks caused them to convert into a series of metasomatites and contact metamorphic rocks. Geostatistic studies on stream sediments and heavy mineral were done and include data processing, (i.e. normalization, univariate and multivariate analysis), and ultimately preparation of anomaly maps. The correlation coefficients among elements were determined. Elements that show positive correlations with gold are Cu, Hg, Pb, As, Sb, Ag, Bi and Mo. The results of preliminary regional geochemical explorations have led to discovery of two anomalous zones for gold; grade 1 and grade 2. The anomalies were verified by studies on heavy minerals in stream sediments and mineralized and altered samples taken from gold anomalous zones. The most important indentified heavy minerals include magnetite, malachite, gold, micaseous hematite, pyrite, galena, cerussite, pyrite- limonite, goethite, limonite, barite, hematite, pyrite- oxide which are affiliated with alteration and mineralzation zones. The major alterations in the area are argillic, sericitic and propylitic developed along the vein’s walls. Field and analytic studies done on samples taken from the gold anomalous zones led to identification of epithermal gold veins having over 4.5 ppm gold grade. The concordance of anomaly map with tectonic map and altered zones indicate that the faulted and fractured zones have played a crucial role in creation of gold anomalous zones. The incorporation of these data in the area led to introduction of several anomalous zones belonging to Au, Ag, Cu, As and Pb that can be used as passfinders for epithermal gold.
Original Research Paper
S Eslami Farsani; M Talebian; A Saidi; M Pourkermani
Abstract
The purpose of this research is to study active faulting in western part of the Middle East, between Caspian Sea to the east and Mediterranean Sea to the west. This region covers several countries and thus geological maps have different scale and errors in locations. The mismatch between fault traces ...
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The purpose of this research is to study active faulting in western part of the Middle East, between Caspian Sea to the east and Mediterranean Sea to the west. This region covers several countries and thus geological maps have different scale and errors in locations. The mismatch between fault traces in geological maps with their actual position on the ground is sometimes up to several hundred meters. The main goal of this study was to prepare continues map of active faults together with seismicity for the entire region of interest. This map also shows the slip rate of the active faults, estimated based on available geodetic measurements (GPS) or other published data. All available information including geological maps, satellite images, topographic data, GPS measurements, and earthquake data were imported into Arc GIS system. The Landsat 7 satellite images were used to correct location of active faults and measuring young offsets along the faults. Most of active faults bound the mountains implying that they control current topography of the region. The earthquakes are more frequent in the Zagros, especially in western part, around junction of the North and East Anatolian faults. This is in contrast with the Dead Sea region where lower seismic activity observed. However larger earthquakes are distributed over entire region, though we have more record of historical earthquakes in NW Iran, Eastern Turkey and the Dead Sea region probably related to documentation of historical data rather than occurence of earthquakes. In the eastern Zagros (NW of Iran) total shortening is partitioned into pure strike-slip and thrusting. In the middle part (eastern Turkey) the Zagros trends east-west and most of shortening is taken up by pure thrusting. The Central and Eastern Turkey is dominated by strike-slip faults and rotation of blocks. Shortening across left-lateral and right-lateral systems in eastern Turkey cause the Turkish block to move to the west and subduct in Hellenic trench. Comparing rate of shortening with moment released by earthquakes in Zagros and Caucuses suggest that part of shortening is taking up by creep.
