Remote Sensing
Mina Zamyad; Peyman Afzal; Mohsen Pourkermani; Reza Nouri; Mohammadreza Jafari
Abstract
Tirka area is situated in NE Iran as a part of the TCMB which consists of Paleogene sediments and volcanic rock units with a combination of Eocene intermediate to basic rocks. The research aim is to determine the alteration zones using C-N fractal model based on ASTER satellite images. First, the ASTER ...
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Tirka area is situated in NE Iran as a part of the TCMB which consists of Paleogene sediments and volcanic rock units with a combination of Eocene intermediate to basic rocks. The research aim is to determine the alteration zones using C-N fractal model based on ASTER satellite images. First, the ASTER data was processed using SFF method for determination of iron oxide, propylitic, phyllic, and argillic alteration zones. The C-N fractal model is utilized for the separation of different parts of alteration zones. The results derived via the C-N fractal model showed that the main trend of the alteration zones is in NE-SW direction. Also, based on the C-N log-log plots, there are six geochemical populations for iron oxide alteration, four geochemical populations for argillic and phyllic alterations, and five geochemical populations for propylitic alteration. There is a high intensity of alteration zones commences with 223 for iron oxide, 204 for argillic, 199 for propylitic and phyllic alteration zones. In order to validate the results, field observations and petrographical studies based on thin-polish sections were carried out. These data confirmed the alteration zones obtained by the modeling. the data obtained from the combination methods, were verified by Logratio matrix,
Economic Geology
Leila Jaberansari; habibollah Torshizian; Nader Kohansal Ghadimvand; Mohsen Pourkermani
Abstract
The current study was conducted on sedimentary units of the 1:100000 sheet of Jam and Sorkheh in Semnan Province, northeast of Iran. Because of its special geochemical properties, lithium can be concentrated in sedimentary rocks with clay minerals. Samples were collected from stream sediments and lithogeochemical ...
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The current study was conducted on sedimentary units of the 1:100000 sheet of Jam and Sorkheh in Semnan Province, northeast of Iran. Because of its special geochemical properties, lithium can be concentrated in sedimentary rocks with clay minerals. Samples were collected from stream sediments and lithogeochemical in three steps and were processed using Concentration-Number fractal modeling. Concentration-Number fractal modeling is a suitable geochemical exploration method to separate anomaly from the background. It was utilized to identify anomalous areas for lithum and the results were presented in the form of maps. As a result, The Gharavol kooh area of Biabanak in central part of sheet of Sorkheh. According to the lithology of the area, which contains marl and clay minerals (Illite and Cholorit), It was main anomaly between the two sheets. This area should be further investigated in Detailed exploration studies.
Tectonics
Golnaz Abbasi; Ali Solgi; Mohsen Pourkermani; Hosein Motamedi; alireza farrokhnia; Keivan Orang
Abstract
We used 2D seismic profiles, field observation and well data to constrain the structural evolution of the Saveh basin during the late-lower Miocene to late Pliocene. During this time period almost 8-9 kilometers of Upper Red Formation (URF) and the Pliocene conglomerates were deposited in the basin depocenter. ...
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We used 2D seismic profiles, field observation and well data to constrain the structural evolution of the Saveh basin during the late-lower Miocene to late Pliocene. During this time period almost 8-9 kilometers of Upper Red Formation (URF) and the Pliocene conglomerates were deposited in the basin depocenter. During the late- lower Miocene (to early- middle Miocene ?), Syn-depositional activity of west-east-northwest-southeast trending high-angle fault zones, with an extensional component, created accommodation space for deposition of lower Upper Red Formation. Since the late- middle Miocene (or late Miocene), initiation of a compressional phase has resulted in regional deformation.The deposition of upper part of the URF and the Pliocene conglomerates was contemporaneous with compressional deformation. During this stage, the middle part of the URF acted as an effective detachment horizon and detachment folds, such as the Saveh and Taraz Naeen anticlines, were formed. The thinning of the Pliocene conglomerates towards the crestal point of these folds indicates late structural growth. According to the top Qom depth map, there are no traps with fault independent closure within the Saveh basin. The top of the Qom Formation is estimated at -4250 m in the Taraz Naeen anticline.
Tectonics
Mohamad Reza Sajadian; Manouchehr Ghorashi; Elahe Javadi Mosavi; Mohsen Pourkermani; Mehran Arian
Volume 28, Issue 110 , December 2018, , Pages 299-306
Abstract
Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics. These indices have the advantage of being calculate from ArcGIS and remote sensing packages over large area as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics. ...
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Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics. These indices have the advantage of being calculate from ArcGIS and remote sensing packages over large area as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics. This is particularly valuable in west-central Alborz where relatively little work on active tectonics based on this method was done, so this method is new and useful. Based upon values of the stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage basin shape (Bs), index of mountain front sinuosity (Smf) and transverse topographic symmetry factor (T), we used an overall index (Iat) that is a combination of the other indices. The low class of Iat are mainly in the sub-basins no; 6, 10,13,14,21,22,23,24,28 and the rest of the study area has moderate tectonic activities in the other sub-basins. Our results show that he moderate value has located along faulted area, which shows 2 class of relative tectonic activity.
R. Akbari Jonosh; M. Ghorashi; Hasan. A. Babaei; M. Nakhaei; M. Pourkermani
Abstract
Considering Iran’s situation in drought risk area, in this study karstic waters are investigated. The study area is located in central of Iran, Semnan province. Several factors are important in Karstification and formation water resources in carbonate, among them important are petrology, topography, ...
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Considering Iran’s situation in drought risk area, in this study karstic waters are investigated. The study area is located in central of Iran, Semnan province. Several factors are important in Karstification and formation water resources in carbonate, among them important are petrology, topography, climate, geomorphology and hydrogeology are pointed out. In this research, the role of structural factors in the development of karstic water resources in Semnan province has been studied. firstly, information layers of each factor prepared. For example, tectonic elements, includes maps: lineament density, faults length density, faults intersection density and density distance from faults making use geological maps and processing of satellite images. Information layers analyzed in the geographical information system (GIS), Expert Choice Software making use geostatistical methods. In this study, multi methods like analytic hierarchy process (AHP) and Fuzzy analytic hierarchy process (Fuzzy AHP) used in study of karstic water resources.
H. Amiranlou; M. Pourkermani; R. Dabiri; M. Qoreshi; S. Bouzari
Abstract
The occurrence of historical and instrumental earthquakes near the North Tabriz Fault in NW Iran is an evidence for seismic activity of this fault, which recorded historical earthquakes with magnitudes greater than 7. In this study, existing experimental relations, historical seismicity, and the fault ...
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The occurrence of historical and instrumental earthquakes near the North Tabriz Fault in NW Iran is an evidence for seismic activity of this fault, which recorded historical earthquakes with magnitudes greater than 7. In this study, existing experimental relations, historical seismicity, and the fault geometry were used to define a Mw 7.7 earthquake scenario. The stochastic finite fault modeling based on a dynamic corner frequency shows a good agreement between maximum estimated acceleration and common attenuation patterns. The derived shake map illustrates that the stongest ground motion is observed in the NW, N and NE of the tabriz city along a zone parallel to the fault. In addition, the maximum acceleration derived from simulation is almost equal to that computed from attenuation patterns.
T. Naderi; M. Pourkermani; A. Shafiei Bafti; M. R. Aminizadeh; S. Bouzari
Abstract
In this study, the permeability of structures associated with Kuhbanan fault zone has been investigated. The Kuhbanan fault zone is one of the most seismically active structural trends in Kerman province. The behaviour of fault zones against groundwater flow (conduit, barrier, or a combination of both) ...
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In this study, the permeability of structures associated with Kuhbanan fault zone has been investigated. The Kuhbanan fault zone is one of the most seismically active structural trends in Kerman province. The behaviour of fault zones against groundwater flow (conduit, barrier, or a combination of both) is relatively controlled by fault core, damage zone, and permeability of fractures and rock units in the fault zone. In this research, qualitative and quantitative data, together with field observations and numerical models have been used. In order to measure the structures in the Kuhbanan fault zone, 23 outcrops were selected for model parameters. Results show that the fault zone acted as barrier in 12 outcrops, conduit in 4 outcrops and a combined barrier-conduit in 6 outcrops. In total, the 61-m-wide southern part of the Kuhbanan fault zone is composed of a fault core of 38 m and a damage zone of 23 m wide, respectively. Therefore, this segment of the Kuhbanan faul zone acts as a combination of conduit and strong barrier for fluid flow. The fault core is well developed but the damage zone is weakly developed , and therefore deformation has been largely localized within the fault core and distributed in the damage zone. To analyze the architecture of the fault zone three Fa, Fs, Fm indices were used. For the southern segment of the Kuhbanan fault zone, the Fa, Fs and Fm were measured as 0.47, 0.73 and 0.51, respectively. The relatively low Fa and high Fs indicate that the Kuhbanan fault zone in this area is not associated with uniform architecture. Also the numerous fault springs in the area are affected by this fault zone.
Z Tashakkori; M Ghorashi; M Pourkermani
Abstract
The Kopet Dagh zone has been an area interest for geologists due to its sedimentary and structural similarities to the Zagros zone. In this study, the Jozek-Ghetlish main fault is introduced using the results of field studies, remote sensing, stratigraphic changes and seismic activities. The studies ...
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The Kopet Dagh zone has been an area interest for geologists due to its sedimentary and structural similarities to the Zagros zone. In this study, the Jozek-Ghetlish main fault is introduced using the results of field studies, remote sensing, stratigraphic changes and seismic activities. The studies show that in terms of seismicity, the earthquakes of August 1943 (Ms 7.6) and February 1976 (Ms 4.3) are the most important events recorded on this fault. From stratigraphy point of view, the facies changes from Shoorijeh formation to Zard formation from east to west is the most obvious stratigraphic change across the fault. Thickness variation (Isopach) maps of the Shoorijeh formation also show that its sickness decreases westward to zero adjacent to the fault, where the Zard formation thickens in the same direction. Deflected and offset stream channels across the southern part of the fault indicate a sinistral displacement along it. The streams draining the Yemendagh mountains in south of Ashkhane are deflected westward across the fault, and some of them show offsets of about 60 to 130 meters. In addition, in the northern part near the reservoir of Shirin Dareh dam, the axis of the syncline supporting the dam reservoir represents a sinistral displacement in the Aytamir sandstones. Further to NE, also, fold axis displacements in the Amirabad syncline, the Miyansoo anticline and even the Gifan syncline are other indications of the left-lateral motion along the fault. According to the NE-SW trend of the fault, its sinistral mechanism, and its effect on the tectonic zonation of this region, the Jozek-Ghetlish fault can be considered as the structural boundary between the eastern and western Kopet Dagh. Also, based upon stratigraphic thickness and facies variations across the fault (Zard and Shoorijeh formation), it can be a key to understand the Kopet Dagh oil reservoirs.
A Barzegari; M Ghorashi; H Nazari; M.A Shokri; M Porkermani
Abstract
The north-south trending Astara Fault System (AFS) is located in the east of Talesh Mountains (TM) and west of the Caspian Sea. The probable seismic activity of this fault system will largely affect the north of GilanProvince. The AFS is one of the basement faults in Iran, which plays an important role ...
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The north-south trending Astara Fault System (AFS) is located in the east of Talesh Mountains (TM) and west of the Caspian Sea. The probable seismic activity of this fault system will largely affect the north of GilanProvince. The AFS is one of the basement faults in Iran, which plays an important role in TaleshMountains region and subsidence of the South Caspian Basin (SCB). It seems that the AFS is the source of moderate to large magnitude instrumental earthquakes such as the 16-4-1913 (Magnitude=5.1), 11-7-1970 (Magnitude Mb=5.2), 4-11-1978 (Magnitude Ms=6.0) earthquakes.However, little is known about historical earthquakes related to the AFS, but it has been probably the source of the 1709AD and 1713AD historical earthquakes in Rasht. In spite of the earthquakes attributed to the AFS, the lack of critical seismic information such as recurrence interval, slip rate and activity rate of the AFS has made its future seismic activity ambiguous. This research aims at assessing the earthquake recurrence interval related to the AFS. Therefore, two different methods, i.e. Gutenberg–Richter and Kijko–Sellovelmethods,were used to estimate the recurrence interval. The results obtained from the Gutenberg–Richter method represent anearthquake of Ms>8 to occur in the interval of 500, 1000 and 2000 years. The results of the Kijko–Sellovel method, however, representearthquakes with the magnitudes of Ms =7.3, Ms =7.7 andMs =7.9 to occur in the interval of 500, 1000 and 2000 years, respectively.
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.
A Khodabakhshnezhad; M Pourkermani; M Arian; A.A Matkan; A Charchi
Abstract
Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics in an area. These indices have the advantage of being calculated using ArcGIS and RS (Remote Sensing) packages over large areas as a reconnaissance tool to identify geomorphic anomalies possibly related ...
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Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics in an area. These indices have the advantage of being calculated using ArcGIS and RS (Remote Sensing) packages over large areas as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics. This is particularly valuable in Great Karoun River Basin of Zagros, where relatively little work on active tectonics based on this method was done. The study area in central Zagros fold- thrust-belt of the southwestern Iran is an area with NW–SE oriented structures provides an ideal location for testing the concept of an index to predict relative tectonic activity on a basis of river system or mountain front. Based upon values of the stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage basin shape (Bs), and index of mountain front sinuosity (Smf), overall index as index of relative active tectonic (Iat) was resulted that is a combination of the other indices. This indices are used to divide the landscape into four classes of relative tectonic activity. After measuring indices it is concluded that this part of the Zagros zone has variable rates of active tectonics. Based on corrected Iat values, the study area was divided into three parts: class 1 (very high relative tectonic activity, %24 in area; such as some parts of the east and central zone where Main Zagros Reverse Fault and Dezful embayment fault have the most influence); class 2 (high relative tectonic activity, 63% in area; such as most parts of the area in east, west, north and center where action of faults are lower than the previous class); class 3(moderate, 10% in area; such as most parts of the area in north and south where action of faults are the lowest). Therefore, we don't have class 4 in this area, and 1% of basin is not measured for the indices because it is located in coastal plain of Khuzestan.
B Taherkhani; H Nazari; M Pourkermani; M Arian
Abstract
The E-W trending North Qazvin Fault is situated in north & northeast of Qazvin city in south-central Alborz. Across the fault, Karaj formation (Eocene) is thrusted over Hezardarreh Formation (A) and the alluvial B Formation. It could be the source for the 1119 AD earthquake with an estimated magnitude ...
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The E-W trending North Qazvin Fault is situated in north & northeast of Qazvin city in south-central Alborz. Across the fault, Karaj formation (Eocene) is thrusted over Hezardarreh Formation (A) and the alluvial B Formation. It could be the source for the 1119 AD earthquake with an estimated magnitude of Ms: 6.5. The North Qazvin Fault is a seismically active fault, therefore it is one of the most important earthquake threats for the Qazvin as an industrial city of Iran. Morphotectonicand detailed field studies along a part of the North Qazvin Fault allows us to measure horizontal and vertical offsets caused by recent movements on this fault. One of the measured horizontal and vertical displacements due to the recent movements on the fault is 4 and 3.5 meters, respectively. The geometry (strike, dip and rake) of the North Qazvin Fault in this part is 090˚, 45˚, 51˚ respectively. Our investigations show that the North Qazvin Fault is a north-dipping compressional fault. The North Qazvin Fault and its surrounding faults such as Najm-abad fault appear as a propagating fault system which has left-lateral compressional kinematics in southern part of the west-central Alborz.
N Bagha; M Ghorashi; M Arian; M Pourkermani; A Solgi
Abstract
Structural development, caused by active tectonics leads to deformation of morphology features. The Mosha-North Tehran fault zone, located in south edge of the Central Alborz consists of significant tectonic structures. Hence, study on morphotectonic signs is a proper method for evaluation of relative ...
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Structural development, caused by active tectonics leads to deformation of morphology features. The Mosha-North Tehran fault zone, located in south edge of the Central Alborz consists of significant tectonic structures. Hence, study on morphotectonic signs is a proper method for evaluation of relative tectonic activities in the area. In this research, six main morphometric indices such as stream length-gradient (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height(Vf), drainage basin shape (Bs), and mountain front sinuosity(Smf)were considered. The computations and probes of these indices indicate three classes of relative tectonic activity in the study area from low to high level. Consequently, the drainage basins with high class of tectonic activity mostly coincide with the main faults in south edge of the Central Alborz.
H Haji Hosseinlou; A Solgi; M Mohajjel; M Pourkermani
Abstract
The Khoy shear zone (KSZ) is exposed 130 Km north of Uremia and 650 km west of Tehran. Structural analysis in the Khoy Shear Zone (KSZ) indicated that they consist of NW-SE oriented various metamorphic rocks. They contain NW-SE trending moderate to steeply dipping mylonitic foliation to the NE. Stretching ...
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The Khoy shear zone (KSZ) is exposed 130 Km north of Uremia and 650 km west of Tehran. Structural analysis in the Khoy Shear Zone (KSZ) indicated that they consist of NW-SE oriented various metamorphic rocks. They contain NW-SE trending moderate to steeply dipping mylonitic foliation to the NE. Stretching lineation plunge shallowly to moderately towards NE. Thrust faults are oriented the same as mylonitic foliation. Ductile fabrics are superimposed by brittle structures. Orientation of the structures indicates that the main stress trend is NE-SW. Four deformation stages (D1-D4) identified in KSZ. The first two stages are ductile that superimposed by the two other ductile-brittle stages. Shear sense indicators such as S/C fabrics, shear bands, shear folds, book-shelf structures, fishes and mantled porphyroclasts indicate that the KSZ deformed via dextral transpression tectonic regime. The Khoy area contains both NW-SE striking dextral strike-slip and SW verging NE dipping ductile reverse shear fabrics. Ductile shear fabrics are overprinted by subsequent younger both thrust and strike-slip fault systems. Abundant syn-tectonic granitoids were intruded in the Khoy area during convergent. The shear deformation fabrics are well identified in both deformed intrusive and metamorphic-ophiolite complex. The geometry and kinematics of shear fabrics indicate a deformation partitioning in both ductile and brittle conditions during a progressive transpression tectonic regime. The KSZ deformed during an oblique convergence scenario between the Arabian and West Alborz- Azerbayjan blocks in NW Iran.
A Shafiei Bafti; M Pourkermani; M Arian; M ghorashi
Abstract
One of the most important tools of recognition for uplifting Movements in an area is study of rivers. The Davaran Mountain Range, which situated between Zarand and Rafsanjan cities, is limited by the Jorjafk fault in the north face. This fault is 160 km long and divided into two northern and southern ...
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One of the most important tools of recognition for uplifting Movements in an area is study of rivers. The Davaran Mountain Range, which situated between Zarand and Rafsanjan cities, is limited by the Jorjafk fault in the north face. This fault is 160 km long and divided into two northern and southern parts. The north part is in the northern margin of Davaran Mountain Range and 100 km long. The southern part is an intra-mountain fault and 60 km long. In the northern part, thrust faulting of the pre-Neogene rock units over the Neogene-quaternary sediments shows the recent activity movements of this fault, although there is no record of historical and instrumental seismicity of the Jorjafk fault. For investigation of uplifting movements caused by this fault, we studied the morphotectonics of rivers limited to this fault. According to our studies, the sinuosity rates for 21 rivers calculated and gave mean ratio of 1.11. The mean ratio of SL index for 15 major rivers is 165.6. The V index shows less than 1 value for 7 rivers. The long profiles of 7 rivers prepared and all show the concave profiles with the minor dome in their long. The minor dome caused by the lithological variations in floor of the rivers. The greatest concaving belongs to river no 5. Our studies show the moderate uplifting values in central part of the Jorjafk fault, near the Hosen village. The uplifting movements show a reduction from the central to the end point of this fault.
A Ghahramani Zakaria; H Nazari; M Pourkermani
Abstract
This research has been achieved with the purpose of morphotectonic studies of the Sufian-Shabestar fault zone in the West Alborz-Azerbaijan (NW Iran). The fault zone cuts the Neogene and Quaternary units in south of the MishoMountains. The maximum of horizontal and vertical displacements along the Sufian-Shabestar ...
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This research has been achieved with the purpose of morphotectonic studies of the Sufian-Shabestar fault zone in the West Alborz-Azerbaijan (NW Iran). The fault zone cuts the Neogene and Quaternary units in south of the MishoMountains. The maximum of horizontal and vertical displacements along the Sufian-Shabestar fault zone are H=2500±200 m in Meshnaq river and V=66±4 m in fan east of Benis village, respectively. The minimum of horizontal and vertical displacements along this fault are H=9±0/5 m in offset stream of N Sharafkhaneh city and V=6±4 m in river NW of Kozehkanan city, respectively, all estimated based on combining data of Digital Elevation Model in scale of 1/25000, aerial photographs in scale of 1/20000, LANDSAT ETM satellite imagery and field studies. The estimated rate of horizontal and vertical displacements are H=135±20 m V=19±4 m in NW of Sharafkhaneh city, respectively and all allow us to estimate the rake of fault by geometry calculations. Based on estimate, the rake of the Shabestar fault segment is 11±4W. The Sufian-Shabestar fault zone is a right lateral-reverse strike slip fault with strike N81E and rake range of between 04, 11 with westwards dip, all estimated based on the rake of fault plane and morphotectonic data. Therefore, the Sufian-Shabestar fault zone (including faults segments of Sufian, Shabestar, F1, Sharafkhaneh (F2) and F3) is neotectonically an active zone.
A.N Pourtaghavi; M Pourkermani; G.R Gharabeigli; Sh Sherkati
Abstract
The western part of Kopet Dagh fold belt is located in NE of Iran. The southern half of this belt is located in Iran and the northern half in Turkmenistan. The Kopet Dagh fold belt can be considered as the second important hydrocarbon province of Iran. Sedimentation in this zone began in Middle Jurassic ...
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The western part of Kopet Dagh fold belt is located in NE of Iran. The southern half of this belt is located in Iran and the northern half in Turkmenistan. The Kopet Dagh fold belt can be considered as the second important hydrocarbon province of Iran. Sedimentation in this zone began in Middle Jurassic due to the intercontinental rifting. The Middle Jurassic sediments lay unconformably on the Paleozoic and Triassic sediments. The geometric pattern of the folds has been studied based on the field work, geological maps, and geophysical data. The results show a thick skin deformation with shortening of about 5% during the tectonic inversion caused by the Pasadenian orogeny phase, which governing the deformation of the region.
Gh Razaghian; A Beitollahi; M Pourkermani; M Arian
Abstract
Iran is in the middle part of the seismic belt of Alps-Himalayas with dissimilar geological, structural and seismological features. In the present article, zonation maps of the earthquake occurrence rate (Rate) and the largest observed earthquakes (Mmax) have been prepared for all the regions of Iran. ...
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Iran is in the middle part of the seismic belt of Alps-Himalayas with dissimilar geological, structural and seismological features. In the present article, zonation maps of the earthquake occurrence rate (Rate) and the largest observed earthquakes (Mmax) have been prepared for all the regions of Iran. The parameter (Rate) shows the number of occurred earthquakes in the year in the region of Iran. Subsequently, according to the zonations, classification of different regions with different seismic activities will be achievable. The zonation map of earthquake occurrence frequency (Rate) in the present article shows that trend of the main classified zonations, according to the calculations, is similar with the geological and structural features of the region. It seems that zonation of Zagros and certain parts of the east of Alborz and Kopedagh with the maximum rate of earthquakes are drastically different with the zonation of central parts of Iran, Makran and eastern part of Iran with low seismic activities. In addition to zonation maps of the earthquake occurrence rate, zonation of the largest observed earthquakes (Mmax) has been provided in this region as well. According to the map, different regions of the Central part of Iran and Alborz with large seismic activities are different with other regions of Iran. Having compared the two zonation maps in this article, it is possible to classify the seismic activities of different regions. The seismic data and the basis of the article are according to the National and International Seismology catalogue for a period of 1900 to 2008.
A. Sistanipour; M. Pourkermani; M. Arian
Abstract
Bafq-Baghin fault system has formed by 8 fault segments. On this fault system has not recorded any historical seismic data. Instrumentally earthquakes are located in low depth and their magnitude is from small to medium. Morphometric parameters and the presence of fault scarp along the fault segments ...
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Bafq-Baghin fault system has formed by 8 fault segments. On this fault system has not recorded any historical seismic data. Instrumentally earthquakes are located in low depth and their magnitude is from small to medium. Morphometric parameters and the presence of fault scarp along the fault segments indicate their activeness. Recent earthquake epicenters of the region (2005-2009) have northeast-southwest trend are located at the intersection of southeast of the Bafq-Baghin fault system. Field investigations and satellite images of region show that the concentration trend of recent earthquake epicenters is located on the cross fault trend that introduced as Rafsanjan-Zarand fault. This fault is one of the X faults in the region that has formed by movement of shear zone.
A. Keynezhad; M. Pourkermani; M. Arian; A. Saeedi; M. Lotfi
Abstract
Detailed geological and structural analysis of north of Torud-Moalleman area (Central Iran), between Anjilu fault in north and Torud fault in the south, led to tectonic elements of this limit such as fractures and relative of their mechanism with left lateral sheared zone of two main faults. This study ...
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Detailed geological and structural analysis of north of Torud-Moalleman area (Central Iran), between Anjilu fault in north and Torud fault in the south, led to tectonic elements of this limit such as fractures and relative of their mechanism with left lateral sheared zone of two main faults. This study provides a movement system of Chalu, Gandi and Hafez faults in this shear zone. On the basis of kinematics findings and using general methods of fault slip analysis (orientation of slip plane, slip vector, shape of stress ellipsoid and angle of internal friction) region stress field were calculated after determining the angle of internal friction for each one of fault limits. Then, the main stress orientation determinates for combination data that values of ،وwere 195/10, 339/78 and 104/07 respectively. The shape of stress ellipsoid was defined on the basis of shape factor, [R= (-) / (-)], (Angelier, 1975). The R-value for whole studied regions was about 0.5 and deformation type was mainly left lateral transpressional with reverse component. Such results are evident from N-NE (N195) trending in the region and northward movement of the lithosphere. These finding are in line with field research results of fractures, faults and mechanism in this general shear zone.
V. Hosseini toudeshki; M. Pourkermani; M. Arian; Kh. Khosrotehrani
Abstract
Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization ...
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Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization of geomorphic anomalies in the Ghezel Ozan River and correlation with structures can specify the role of structures in making active deformations. The intense and sudden deflection in the river course, the abnormal changes in the river sinuosity and knick points upon longitudinal profile of the river are the geomorphic anomalies connected to the structures. Deflection of the river course and abnormal changes in the river sinuosity are identified on the satellite images and approved through field observations. Knick points are specified upon longitudinal profiles of the river and the effects of lithology are surveyed in making of them٫ so that only knick points are considered which are produced by structures. Longitudinal profiles of the river have been obtained from digital elevation model. Above mentioned anomalies then have been correlated with structures extracted from geology maps and in this manner structures effective in making geomorphic anomalies have been identified. The study region is located in Sanandaj – Sirjan, Centeral Iran and Western Alborz zones. Around the Ghezel Ozan River, marl, sandstone, siltstone, limestone, tuff, agglomerate and volcanic rocks are extremely exposed. These rocks belong to Qom, Upper Red, Lower Red and karaj formations. Deflection of the Ghezel Ozan River is surveyed in the regions of Kuh-e-Palangi, Jelovdarlou, Cham and Yengejeh. Abnormal changes in river sinuosity is studied in regions of Jomaelou, Gol gheshlagh, Armoutlou, Kuh-e-Qaravol, Ghaflankuh and Kuh-e-Pajdar. In the regions of Sharif Abad, Iemir, Kuh-e-Qaravol and Kuh-e-Pajdar, knick points are specified upon longitudinal profile of the Ghezel Ozan River. The obtained results show that folds with trends of NW – SE and NE – SW have the highest influence on deflection of the course of the Ghezel Ozan River. The other geomorphic anomalies produced by faults with trends of NW–SE , NE – SW, N-S and E-W especially in instances that faults with trends of NW – SE and NE – SW have intersected. Thus, the most active structural trends in around of the Ghezel Ozan River are trends of NW–SE, NE – SW, N-S and E-W which correlate with trends of fractures in basement of Iran. In this way active folds and faults are identified in the area.
J. Faslebahar; M. Pourkermani; S. Faslebahar
Abstract
Mud volcanoes are one of the interesting phenomenons that many researchers in oil field, plate tectonics and geotourism consider the most. In this regard there are many studies in the other countries, especially those which have this phenomenon and published many articles. This article is the output ...
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Mud volcanoes are one of the interesting phenomenons that many researchers in oil field, plate tectonics and geotourism consider the most. In this regard there are many studies in the other countries, especially those which have this phenomenon and published many articles. This article is the output of researches about anatomical characteristics of active, non active mud volcanoes and hidden diapir in the study region. Due to the subduction of Caspian Sea bed under the continental crust in southeast zone of Caspian Sea, there are a series of anticlines and synclinals which located in the west section NW-SE, in the middle section W-E and east section to Turkmanestan NE-SW. Due to the increase in the west thickness of Cheleken and Aghchagyl formations, Apsheron stage and Quaternary series that are calcareous, marl, clay and sandy and consist of gastropod and lamellibranches remains overlaying on each other conformity there are more mud volcanoes in west and southwest of Caspian Sea. There are 3 active, semi-active and few non active diapirs as well as a hidden one. Mud volcanoes at the southeast, semi- active and hidden diapir section of Caspian Sea, are almost in same direction with Caspian Sea fault. The seismic studies in the region show Plio–Quaternary compressive pressures and subsidence in the form of diapir is present on the surface. Anatomy of mud volcanoes of the region shows their history goes back to upper period Pliocene and scientifically their origin are tectonic-sedimentary.
M.A. Ghorbani; M. Mohajel; M. Pourkermani; M. Alimohammadi; H. Kheyrollahi
Abstract
Hired area is located in the northeastern border of Lut zone and western vicinity of Sistan suture zone. Northern part of Sistan suture zone trending NW-SE with complicated structure is the locality of several considerable ore deposits. We have employed aeromagnetic data, satellite images and field observations ...
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Hired area is located in the northeastern border of Lut zone and western vicinity of Sistan suture zone. Northern part of Sistan suture zone trending NW-SE with complicated structure is the locality of several considerable ore deposits. We have employed aeromagnetic data, satellite images and field observations to consider the relation of surface and subsurface structures to the significant superficial structural features of Hired mining area. Aeromagnetic data were processed by applying appropriate filters including Reduction to pole and First vertical derivative for proper distinguishing the magnetic features. In addition, highpass filters were used for edge sharpening of the ASTER images.
Aeromagnetic data have shown two main N-S and NW-SE structural directions which follow the northern Sistan suture zone. Presence of mineralized and altered veins and brittle shear zones with the same trend around the fractures is noticeable. Moreover, fractures intersections and conjuncture places are dramatically compatible with mineralization areas. Another result from aeromagnetic data is identification of a circular structure in the east of study area. The gold mineralization has occurred in the west part of mentioned structure which is strongly affected by NNW striking features. Satellite images in addition to confirmation of aforesaid structural trends imply a third structural NE-SW strike. This structure is not vivid on the aeromagnetic map and has only an ambiguous trace on it. Our field measurements verify this new structural trend as well.