Sedimentology
Afshin Karimkhani-Bahador; Sadat Feiznia; Mohsen Aleali; Mehran Arian
Abstract
To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy ...
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To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy of waves and sea currents, as well as how the slope of the seabed changes, play a role in the production and diversity of the sedimentary facies. 9 sedimentary facies are the most abundant in the surface deposits of this area and on average, in the sediments of the continental shelf, there are 1% by weight of coarse-grained particles, 25% by weight of medium-grained particles and 74% by weight of fine-grained particles. The composition of sedimentary facies in this area is controlled by indicators such as the size of sedimentary particles, the amount of sedimentary load carried to the environment, the energy of waves and sea currents, and how the slope of the seabed changes. In the marine environment of the study area, sub-sedimentary environments, Backshore, Foreshore, Shoreface, Offshore transition zone and offshore can be identified. The two facies of slightly gravelly Mud and Mud are more abundant than other facies.
Stratigraphy and Palaeontology
Ali Jalali; Hamed Yarahmadzahi; Mehran Arian; Abdollah Saidi; Seyed Mohsen Aleali
Abstract
The Shishtou section is located in the north of Tabas Ghezelin and Asselian sequences of Zaladou formation with 60 m thickness are divided into five units, includes sandstone, limestone, shale, sandy limestone and limestone. The lower boundary of the Gzhelian deposits with disconformity on top of the ...
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The Shishtou section is located in the north of Tabas Ghezelin and Asselian sequences of Zaladou formation with 60 m thickness are divided into five units, includes sandstone, limestone, shale, sandy limestone and limestone. The lower boundary of the Gzhelian deposits with disconformity on top of the Moscovian deposits of the Abshani formation. The upper boundary of these deposits with the Tighe-Madanou formation is continuous. The assemblages of fusulinids in the Shishtou section such as Ruzhenzevites-Rauserites-Triticites are identified in the upper part of Gzhalian previously reported from equal deposits in Darvaz, Fergana, Southern Urals, Donetsk and Carnic of Alps, as well as, Central Iran, Central Alborz and Sanandaj-Sirjan zones. Also, different species of Sphaeroschwagerina, Pseudoschwagerina and Likharevites, which illustrate the Asselian age, represent the Carboniferous-Permian boundary in the studied section and allow for comparability with other structural-sedimentary zones of Iran, including Central Iran , Central Alborz (Doroud Group) and Sanandaj-Sirjan zone. This equivalence expresses the transgressive of sea level in different parts of Iran in the late Carboniferous and early Permian periods. In Shishto section 15 genera ,35 species and 2 subspecies of Fusulins have been identified, some of which are reported for the first time from Iran.
Tectonics
Zeynab Taslimi; Abdollah Saidi; Mehran Arian; A. Solgi; Manouchehr Ghoreshi
Abstract
The Alborz Mountains has been separated the subsiding Caspian Basin from the foreland basin of Central Iran. This mountain range from east to northwest, has changed greatly in structural trend formed spirally. Two orogenic phases, Cimmerian and Alpine events caused more changing in sedimentary basin ...
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The Alborz Mountains has been separated the subsiding Caspian Basin from the foreland basin of Central Iran. This mountain range from east to northwest, has changed greatly in structural trend formed spirally. Two orogenic phases, Cimmerian and Alpine events caused more changing in sedimentary basin of Palo Tethys and Neotethys and it caused the complexity of abundant structural in other way too. The aim of this research is to investigate and analysis of existence structures in east central Alborz from northwest of Damghan (South of Toyeh) to South of Sari (North Alborz fault). The Structural features Analysis indicate that the Alborz Mountains are a fold and thrust belt. During the intense shortening of Alborz crust in the studied area the initial model of folds have been modified or destroyed. Some of these folds could take place in flexural flow folds or Drug folds classes since one limb of folds on the surface of low-angel thrust faults was thrusted recumbently. The thrust faults with south and north dipping is the main controller for variety structures in this part of Alborz. Based on geological and structural properties, construction of folding structures initiated during the Alpine orogeny since the late Eocene (37 million years) and the most shortening and faulting had occurred during at the Late Miocene. Data presented here demonstrate that shortening percent in the study area of Alborz Mountains is about 36.27% and the Rate of Shortening is estimated about 0.93 mm/y.
Sedimentology
Zeinab Aalishavandi; Hossain Rahimpour-Bonab; Ali Kadkhodaei; Mehran Arian
Abstract
The Sarvak Formation deposited in the North to Northeastern margin of the Arabian Platform during the Mid-Cretaceous, and is extensively encountered in the Folded Zagros of southwestern Iran. It is the most important reservoir unit after the Asmari Formation in Iran. Petrographic analysis of the drilled ...
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The Sarvak Formation deposited in the North to Northeastern margin of the Arabian Platform during the Mid-Cretaceous, and is extensively encountered in the Folded Zagros of southwestern Iran. It is the most important reservoir unit after the Asmari Formation in Iran. Petrographic analysis of the drilled wells of the Kupal oil field led to recognition of in studied wells led to determination of eight microfacies that deposited in 3 sub-environments; restricted lagoon, lagoon-open marine and shoal in an interior part of Continental carbonate ramp. Petrographic studies revealed that since deposition, the Sarvak Formation experienced several diagenetic realms including marine, meteoric, burial and telogenetic diagenetic environments. Location of the studied wells shows that the relative depth of the Sarvak Formation ramp increases from the east to the west. These diagenetic successions are mainly restricted to the upper and lower parts of the Cenomanian-Turonian disconformity. Meteoric water infiltration below this Cenomanian-Turonian disconfirm boundary and related Dissolution led to development of moldic and vuggy porosity And as a result, the reservoir potential has been increase. In this study Hydraulic flow units were identified firstly using flow zone indicators and secondly using a stratigraphic modified Lorenz plot. The flow units resulting from these two methods are compared, and their close correspondence within the sequence stratigraphic framework is discussed. Base on this results six hydraulic flow units are defined as flow units 1 and 2 of the best reservoir quality and the reservoir potential reduced to the flow unit 6.
Tectonics
Zahra Mohammadyasl; Abdollah Saidi; Mehran Arian; Ali Solgi; taher Farhadinejud
Abstract
The Studied area is located in the small part of the structural zone of Urumieh- Dokhtar Magmatic Arc, at 60km far from south of Qom and 12km far from south east of Kahak. In the beginning, 1:25000 map of the area was prepared, because, region is located in two 1:100000 scale map sheet of Kahak and Aran, ...
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The Studied area is located in the small part of the structural zone of Urumieh- Dokhtar Magmatic Arc, at 60km far from south of Qom and 12km far from south east of Kahak. In the beginning, 1:25000 map of the area was prepared, because, region is located in two 1:100000 scale map sheet of Kahak and Aran, and more rock units were separated. In the next step, in a several step of the field observations, 17 samples of regional volcanic rocks were taken for XRF and ICP chemical analysis, and they main Oxides, heavy metals and rare elements were identife. Most of the samples have been located in the Calk- alkaline series, and some in the Tulleit series. In the lithology diagrams, these samples respectively are arranged in the range of Andesite, Dacite, Trachy Andesite and Rhyolite Rocks. Due to the anomalies and the amount of Nb in the samples of the region, they formation can be related to the subduction zone. On the other hand, the depletion of Nb and Ti is special in magmatism in the subduction zone. Because in the subduction regions released fluids from floating lithospheric rich in LILE, increases in the mantle wedge. Since in the study area rocks exhibit calc- alkaline with moderate to high potassium, it can be concluded that the stones are related to active continental margin associated with subduction.
Tectonics
Sepideh Rezabeyk; Abdollah Saidi; Mehran Arian; Ali Sorbi
Abstract
In the Northern part of Suture Zone (Kermanshah) the deep sea sediments, oceanic crust remnants, platform carbonates, igneous and metamorphosed rock of active margin and carbonate sequence of passive margin are assembled in this studied area. This convergent area has provided a very complicated structural ...
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In the Northern part of Suture Zone (Kermanshah) the deep sea sediments, oceanic crust remnants, platform carbonates, igneous and metamorphosed rock of active margin and carbonate sequence of passive margin are assembled in this studied area. This convergent area has provided a very complicated structural zone. The main purpose of this study is stress characteristic analysis. A great data has gathered from the faults which are appeared within the rocks specially the radiolaritic rocks. The data includes characteristics of fault surface geometry, fault slip and lineation slip related. By using the method Right Dihedral, the position of main stress was obtained. The great number of reverse faults have a NW- SW trend, while the strike- slip faults, show a NE- SW direction. The Normal faults with a different displacements appeared younger than the other faults. The result of this study that we obtained the situation of main stress σ1, σ2 and σ3 respectively is 059, 305 and 195.
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.
Masoumeh Nabilou; Mehran Arian; Peyman Afzal; Ahmad Adib; Ahmad Kazemi Mehrnia
Abstract
The multifractal modelling is an effective approach for separation of geological and mineralized zones from the background. Following cases are addressed in this study; Concentration-Distance to Major Fault structures (C-DMF) fractal model and distribution of the known Fe indices/mines in the Bafgh ...
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The multifractal modelling is an effective approach for separation of geological and mineralized zones from the background. Following cases are addressed in this study; Concentration-Distance to Major Fault structures (C-DMF) fractal model and distribution of the known Fe indices/mines in the Bafgh area to distinguish the Fe mineralization based on their distance to basement faults, surface faults and master joints, using remote sensing information, airborne geophysics information and field surveys. Application of the C-DMF model for the classification of Fe mineralization in the Esfordi and Behabad 1: 100,000 sheets reveals that the main Fe mineralizations have a strong correlation with their distance to the major and basement faults. Accordingly, the distances of Fe mineralization that has the grades upper than 55% in this area )43%≤S≤60%), are lower than 1 km related to basement faults, while such distance for this threshold is 2344<DMJ≤1778 meter for the master joint and also for the faults of 1:100,000 Behabad and Esfordi geology sheets in 43%S≤60% threshold (for the graides) the distances are 3162<DGF≤4365 meter to the faults. This indicates a positive correlation between Fe mineralization and distance to the basement faults. On the other words, the proximity evidence for the Precambrian high grades Fe deposits related to basement faults indicates syn-rifting tectonic events. This C-DMF fractal model can be used in exploration of the magmatic and hydrothermal ore deposits.
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.
M Nazemi; M Qurashi; M.R Ghassemi; M Arian
Abstract
Geomorphic characteristics of alluvial fans on the sides of the ShotoriMountains in east of Tabas represent two different groups . The first group is older and is more dominant with their heads near the ShotoriMountains' hillside and their toe spreading to the central parts of the plain. These alluvial ...
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Geomorphic characteristics of alluvial fans on the sides of the ShotoriMountains in east of Tabas represent two different groups . The first group is older and is more dominant with their heads near the ShotoriMountains' hillside and their toe spreading to the central parts of the plain. These alluvial fans on which no main recent channel sedimentation is occurring, are often consisted of old alluvial sediments with a thin cover of newer ones. The second group includes younger and active alluvial fans consisted of more recent sediments of stream bed, which are located at the termination of the first group or at the southern foothills of the ShotoriMountains. It can be said that in the first group, recent active sedimentation process by the main channel has been transferred to the lower parts and toe of the alluvial fan, but in the latter group sedimentation has been done on top of the alluvial fan and on older sediments. In other words, the first group consists of two obvious old and active (recent) parts, while the second group only includes recent and active alluvial fans. Our investigations indictaes that geomorphic pattern of these two alluvial fan groups has a clear relation with location and mechanism of active faults and geomorphic surfaces in the plain of Tabas and eastern slopes of the Shotori Mountains; in other words, it is related to the mechanism of structural evolution of this mountain. According to this pattern, wherever there is the active fault of the catastrophic 1978 earthquake at the front of mountain along which the ShotoriMountains are being uplifted, the second type of alluvial fans is formed. Where the fault is located in central parts of the plain as a result of deformational front propagation, and the old part of the alluvial fan and mountain are being uplifted along it, the first type of alluvial fans (with two separate parts) is formed. This uplift is accommodated by active faulting and folding associated with bedding plane faulting. Migration of deformational front during geologic evolution of the ShotoriMountains has caused four different geomorphic levels along with three generations of alluvial fans. It is concluded that investigating on geomorphic pattern of alluvial fans will provide valuable data about the location of active Quaternary faults in alluvial plains. This pattern shows an active fault near Boshruyeh (east of the ShotoriMountains). Although no major earthquake has been reported from the fault, all morphotectonic evidences show its activity and thus the occurrence of large earthquakes in the future is expected.
F Baratpour; M Arian; A S
Abstract
Situated 15 km NW of the Izeh city, Tukak and Kamarun anticlines are located in northwest of the Izeh zone in the Zagros fold-and-thrust belt. The Tukak anticline measures about 17 km length by 3.3 km width on the Asmari formation outcrop, while the Kamarun anticline shows a maximum length and width ...
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Situated 15 km NW of the Izeh city, Tukak and Kamarun anticlines are located in northwest of the Izeh zone in the Zagros fold-and-thrust belt. The Tukak anticline measures about 17 km length by 3.3 km width on the Asmari formation outcrop, while the Kamarun anticline shows a maximum length and width of about 15 km and 3.5 km, respectively, on the same formation. The SE termination of the Kamarun anticline and the NW termination of the Tukak anticline form together an en-echelon array. Both anticlines represent nearly symmetrical box-fold geometry, in which the Pabdeh formation is the oldest outcrop in each anticlinal core and the Asmari formation constitutes most of their surface outcrop. Based on surface geology, 4 cross-sections across the Tukak anticline and 3 cross-sections across the Kamarun anticline (D-D' is a common section crossing the en-echelon plunges), and one longitudinal section through both structures were constructed. Since the Bangestan horizon is taken to indicate a position upper than sea level, the cross-sections were used to construct the UGC map on the Upper Khami horizon. In Tukak anticline, which is bigger than the Kamarun anticline, the UGC map of the Upper Khami horizon illustrates vertical and horizontal closures of 250 m and about 4.3 km2, respectively.
J Ehsani; M Arian; M Ghorashi
Abstract
This paper aims at evaluating relative active tectonics in the Jarahi-Hendijan drainage basin based on geomorphic indices. Indices used include: stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage ...
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This paper aims at evaluating relative active tectonics in the Jarahi-Hendijan drainage basin based on geomorphic indices. Indices used include: 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). Results from the analyses were combined to achieve an index of relative active tectonics (Iat), which is divided into four classes implying relatively low to very high tectonic activity. The study area is located across the Zagros Mountains belt (high Zagros, folded belt, and frontal lowlands) in southwest Iran, and comprises an ideal location to test the concept of an index to predict relative tectonic activity on a basis of area rather than a single valley or mountain front. Recent investigations show that neotectonism has played a key role in the geomorphic evolution of this part of the Zagros ranges. Geomorphic indices indicate the presence of differential uplifting in the geological past. Higher values of Iat (low tectonic activity) mainly occur in the southwest of the Jarahi- Hendijan drainage basin, while the rest of the study area falls into classes of Iat that indicate moderate to high tectonic activity. Baghmalek and Takhtderaz sub-basins show the highest values of relative tectonic activity. The distribution of this index defines areas associated with different faults and relative rates of tectonic activity. Nearly 40% of the study area is classified into Classes 1 and 2 implying very high to high tectonic activity, and 37% is grouped as Class 4, which is taken to indicate low tectonic activity. Areas of higher relative tectonic activity represent lower Iat values.
L Amirbahador; H Rahimpour-Bonab; M Arian
Abstract
This study is focused on the microfacies and facies associations in the 540 meter-thick interval of the Late Permian Upper Dalan reservoirs in the South Pars Gas Field using the petrographic studies, image analysis techniques and quantitative analysis of the constituting components. The petrographic ...
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This study is focused on the microfacies and facies associations in the 540 meter-thick interval of the Late Permian Upper Dalan reservoirs in the South Pars Gas Field using the petrographic studies, image analysis techniques and quantitative analysis of the constituting components. The petrographic studies led to the recognition of 15 microfacies that formed in four facies associations: peritidal, lagoon, shoal and off shoal. Due to the high frequency of the shoal facies in the Upper Dalan, those have been investigated in details. The relative sea-level changes during deposition of the Upper Dalan member were examined using the vertical microfacies and facies association’s variations. The main focus of this study is to investigate the microfacies variations and depositional environment evolutions in the Upper Dalan member in response to the relative sea-level changes. The frequency analysis of the facies revealed that during the Late Permian, a major fall has been occurred in relative sea-level recorded in the lower (K4 unit) and upper (K3 unit) parts of the Upper Dalan member. In these intervals, the facies change from ooid-bioclastic shoals to the alternative layers of shoal-lagoon-peritidal facies. As well, anhydrite precipitation and dolomitization are prominent diagenetic features, which are indications of climate change. The facies variations were used to reconstruct the relative sea-level changes during deposition of the Upper Dalan member in the South Pars Gas Field. As a result, two and a half third-order and 12 fourth-order cycles have been distinguished.
M Haj Manuchehri; M Arian; M Ghorashi; A Solgi; A Sorbi
Abstract
Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics. These indices have the advantage of being calculated from ArcGIS and Remote Sensing software packages over large areas as a reconnaissance tool to identify possible geomorphic anomalies related to active ...
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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 calculated from ArcGIS and Remote Sensing software packages over large areas as a reconnaissance tool to identify possible geomorphic anomalies related to active tectonics. This method is particularly new and useful in areas where relatively little work has been carried out on active tectonics based on this method. Based upon the values of 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), we used an integrated index (Iat) that is a combination of the other indices. This index divides the landscape into four classes of relative tectonic activity. According to the Iat results, sub-basins 4 and 6 show zones of low tectonics activity (Class 4), sub-basins 1, 2, 7, 9, 10, 11, 12, 14, 15 and 19 fit to areas of moderate tectonic activity (Class 3), and high tectonic activity is represented by sub-basins 3, 5, 8, 13, 16, 17 and 18 (Class 2). The Tranverse Topographic Symmetry (T) was also studied using morphometric measurements, which finally gave a plot of T-vectors defining anomalous zones of basin asymmetry. A comparison between T index and map of relative tectonic activity showed a consistent coincidence between areas of higher Iat classes with zones of greater asymmetry.
Z Maleki; M Arian; A Solgi; M.A Ganjavian
Abstract
The Karbasi anticline is located to the west-northwest of the Jahrom town, and 40 km to the northwest of Aghar gas anticline in interior Fars region. The anticline has an asymmetric structure, and some faults with large strike separations are observed in it. Because of the importance of comparison between ...
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The Karbasi anticline is located to the west-northwest of the Jahrom town, and 40 km to the northwest of Aghar gas anticline in interior Fars region. The anticline has an asymmetric structure, and some faults with large strike separations are observed in it. Because of the importance of comparison between the folds, and understanding folding patterns in different systems, analysis and description of basic elements of fold style is considered as a major components in structural studies. The aim of this study is to analyze the elements of fold style in the Karbasi anticline located in the interior Fars, in order to contribute to the exploration goals of hydrocarbon. The software used in this study include Tectonics FP, Global Mapper, and software related to Geo Modelling. Analysis of fold style elements in the different parts of the Karbasi anticline indicates changes in the pattern of folding. The changes in the western part of the Karbasi anticline is different from other parts of the anticline. Based on prepared stereoplots, fold axis and axial plane show major changes in the western part of the anticline. In the study area Dashtak Formation as a middle detachment unit plays a major role in development of the geometry of folds. Based on our results, it seems the western part of the anticline is affected by more deformation. It is probable that in this part, the Nezam-Abad fault has caused rotation of the western plunge of the fold towards north, and has affected the Karbasi anticline. Based on the modeling done for the study area, a secondary fault is indicated related to the Nezamabad fault.
U Alladin; M Talebian; M Arian; M.M Ahmadi
Abstract
Earthquake is an undeniable phenomenon that can cause financial and social damage if occur in populated areas. Vulnerability of buildings is not just function of magnitude and distance from the epicenter but also depends on physical properties of soil. In this study we evaluate physical properties ...
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Earthquake is an undeniable phenomenon that can cause financial and social damage if occur in populated areas. Vulnerability of buildings is not just function of magnitude and distance from the epicenter but also depends on physical properties of soil. In this study we evaluate physical properties of alluvium in an area of approximately 100 square kilometers in west of Tehran between longitudes 51 º 15´ to 51º 23´ and latitudes 35º 40´ to 35º 50´. As a first step we collected field data regarding the alluvium deposits as well as location of Quaternary faults. We then combined this information with data from 440 boreholes which were aquired from more than hundred urban development projects. We use sedimentological diagrams of the boreholes to define three zones of coarse-, intermediate- and fine-grained material in the region. We considered physical and mechanical properties of the sediments to produce seismic amplification map of the area which shows three zones of high, moderate and no amplification. Finally, we investigated liquefaction potential of sediments, considering ground water level and structure of the basin and we have concluded that there is no potential of liquefaction in the area of study.
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.
S Bahiraee; M Arian; M Qorashi; A Solgi
Abstract
The Mosha fault is the most important fault structures in the south of Central Alborz. According to the activity of this fault, confirmation of the morphological evidences, and large historical earthquakes occurred by its activity, also proximity to Tehran metropolitan, the study of this area is very ...
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The Mosha fault is the most important fault structures in the south of Central Alborz. According to the activity of this fault, confirmation of the morphological evidences, and large historical earthquakes occurred by its activity, also proximity to Tehran metropolitan, the study of this area is very important. Therefore, as a parameter, evaluation of the fault movement potential helps us in seismological study of the area. In this paper, we have used the model presented by Lee et al. (1997) to evaluate movement potential. The model is based on the relationship between fault geometrical characteristics and regional tectonic stress field. To use the equations of this model, structural data of 13 stations along the Mosha fault were collected to identify the position of the principal axes of stress. Then, we obtained the direction of maximum principal stress of the Mosha fault and also for each section separately by using Inversion method and they were placed in equations.
H Alizadeh; M Aryan; M Lotfi; M Ghorashi; M Ghorbani
Abstract
The Dehaj-Sardoiyeh Belt, which is a part of the Urmia-Dokhtar Volcanic-Plutonic Zone, consists of several economic porphyry copper deposits. This area is located on the right lateral shear zone surrounded by the Rafsanjan fault in the north and the Shahr-e Babak fault in the south. In this research, ...
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The Dehaj-Sardoiyeh Belt, which is a part of the Urmia-Dokhtar Volcanic-Plutonic Zone, consists of several economic porphyry copper deposits. This area is located on the right lateral shear zone surrounded by the Rafsanjan fault in the north and the Shahr-e Babak fault in the south. In this research, spatial relationship among sixteen porphyry copper deposits, faults and fractures was studied. The results show a strong relationship between the Photo lineament factor and location of the porphyry copper deposits. The direction of lineament factor (d/D) was found to be highly correlated with the location of porphyry deposits. The results can be used in exploring preliminary porphyry deposits with regard to the geometry and mechanisms of the faults and fractures.
M.R Asghari; M Moktari; M Arian; M.R Vanaki
Abstract
This study has been done on “Ferdowsi” oil field, which is located on Persian Gulf. The geological studies show that the north slope of the field is situated along the Arabian shield in which its structure has been affected by the salt mass. The Fahliyan formation is the main reservoir in ...
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This study has been done on “Ferdowsi” oil field, which is located on Persian Gulf. The geological studies show that the north slope of the field is situated along the Arabian shield in which its structure has been affected by the salt mass. The Fahliyan formation is the main reservoir in the field. In order to interpret seismic data, firstly by using sonic and density logs, synthetic wavelet was constructed and compared to pseudo 3D seismic data using software. Then, formation tops were picked, and time and depth maps were prepared. Acoustic Impedance pseudo 3D volumes were performed by preparing seismic inversion. It is to note that seismic attributes help greatly to estimate reservoir properties of target formation and it is useful in better identifying the reservoir and drilling wells with reduced cost impact. In addition, in this study, faults and stratigraphic features (such as channel) were recognized by seismic attributes that is important for development of the field.
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.
Mehran Arian; R. Mohammadian
Abstract
Marun oil field is situated on the eastern part of Dezful Embayment zone (Zagros).Aghajari Formation is cropping out on the surface. Asmari formation, Bangestan and Khami Groups are the Main reservoirs in this field. Asmari formation with six reservoirs layers is the most important reservoir. Dolomitic ...
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Marun oil field is situated on the eastern part of Dezful Embayment zone (Zagros).Aghajari Formation is cropping out on the surface. Asmari formation, Bangestan and Khami Groups are the Main reservoirs in this field. Asmari formation with six reservoirs layers is the most important reservoir. Dolomitic carbonates are dominant lithology in the 1,2,3layers and so, fracture density is high, especially in the first layer(90% Dolomite).Increasing of shale and Marle Layers in the 4,5,6 layers caused to decreasing of brittle property and fracture density is low. According to this research, Marun Anticline is a fault (thrust) related fold with faulted Detachment Fold mechanism. Two major fractures system in the Marun oil field could be recognized which are regional fractures (with east-west trending) and local fractures (fold and bending related fractures). The main fractured sectors, Marun Anticline are being seen in the southern limb and the eastern part of northern limb by curvature investigation (by Differential and Graphical methods).The results of Isopermeability, RFT, PI maps are consistable with the results of fracture study in order to identification of fractured sectors in the Marun Anticline
Mehran Arian; S. Keshavarzi Dana
Abstract
The Buneh Kuh anticline (with 25 km length and 7 to 17 km width) is a NW-SE trending anticline in the Coastal Fars Sub-basin (Zagros simple folded belt). Gachsaran formation is cropping out in the core of this anticline. In this paper the elements of fold style and folding mechanism have been investigated ...
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The Buneh Kuh anticline (with 25 km length and 7 to 17 km width) is a NW-SE trending anticline in the Coastal Fars Sub-basin (Zagros simple folded belt). Gachsaran formation is cropping out in the core of this anticline. In this paper the elements of fold style and folding mechanism have been investigated in the Buneh Kuh anticline. It is an asymmetric detachment fold on the Hormoz Formation. Herang anticline is a NW continuation of the Buneh Kuh anticline. Sub-surface contour map on the top of the Dehram group (gas reservoir) was prepared and its western culmination (near to the DD’ cross section) could be recommended for drilling.
