Fault

Open Access Article

1 - The geometric and kinematic analysis of the Kabir-Kuh and Chenareh anticlines in the Zagros Fold-Thrust Belt
فاطمه زینعلی mohammad hosein goudarzi

20.1001.1.17357128.1394.9.34.2.6

Kabir-Kuh and Chenareh anticlines are located in the Lurestan Province of the Zagros fold-thrust belt. The geometry and kinematic evolution of folds in the Zagros fold-thrust belt are controlled by thrust faults. In this paper, the geometry of the Kabir-Kuh and Chenareh More

Kabir-Kuh and Chenareh anticlines are located in the Lurestan Province of the Zagros fold-thrust belt. The geometry and kinematic evolution of folds in the Zagros fold-thrust belt are controlled by thrust faults. In this paper, the geometry of the Kabir-Kuh and Chenareh anticlines is investigated in order to analyze their deformation style. To analyze the deformation style of these anticlines, five structural cross-sections were measured perpendicular to the axial surface trace of the anticlines. Based on geometric and kinematic analysis, Kabir-Kuh and Chenareh anticlines have a geometry similar to faulted-detachment folds with multi-detachment levels. The detachment level above which the folds formed is probably located in the Lower Paleozoic series. Also structural cross-sections represent an important contribution of the Dashtak Formation as intermediate level in the development of deformation in this part of the Lurestan Province. Manuscript profile

Open Access Article

2 - Non-coaxial deformation in sphalerite strain fringe: A kinematic shear indicator in overturned limb of a hanging wall fold
علي Nakini علي Yarmohammadi

20.1001.1.17357128.1394.9.34.3.7

Kinematic evidence of shear deformation in strain fringes of sphalerite mineral in an overturned limb of a fold structure are studied. Structural observation in Cretaceous rocks of Tiran Mine Area in west Esfahan, reveals a shear deformation in overturned limb of More

Kinematic evidence of shear deformation in strain fringes of sphalerite mineral in an overturned limb of a fold structure are studied. Structural observation in Cretaceous rocks of Tiran Mine Area in west Esfahan, reveals a shear deformation in overturned limb of a hanging-wall anticline that has generated with reverse fault in the area. Orientation of strain fibers and their rotations in strain fringes of sphalerite minerals are used for determination of stress orientations and its changes during shear deformation process. This fabric indicates kinematic evolution of the overturned limb of a hanging-wall anticline and related reverse fault during folding. In this study, amount of stretching in strain fringes and their rotation are measured by object-centre path model. Manuscript profile

Open Access Article

3 - Tectonic geomorphology approach in the assessment of fold- growth mechanism within the Zagros Fold-Thrust Belt
آرش جمشیدی معصومه Vatandoust بهنام Oveisi علی فقیه

20.1001.1.17357128.1394.9.33.1.3

Zagros Fold-Thrust Belt consists of several fault–related folds which important hydrocarbon reservoirs are formed in relation to their evolution. Understanding of fold geometry and its growth pattern are affective parameters in the exploration and drilling programs of More

Zagros Fold-Thrust Belt consists of several fault–related folds which important hydrocarbon reservoirs are formed in relation to their evolution. Understanding of fold geometry and its growth pattern are affective parameters in the exploration and drilling programs of hydrocarbon reservoirs. In this research, stream bed erosion pattern and quantitative morphometric indices were used as geomorphic indicators to recognition the mechanism of fold-growth. Results of geomorphic investigation reveal dominant of detachment folding pattern in the coastal Fars area. Moreover, the effect of change in the thickness of detachment horizon on the folding pattern was evaluated. Manuscript profile

Open Access Article

4 - Morphotectonics and Paleoseismology investigation on Sahlan Fault Fragment, NW segment of the North Tabriz Fault
الهه احمدزاده Samane Aliakbar Nazari Talebian Solaymani Azad Marzieh Faridi Masouleh

The North Tabriz Fault is one of the major strike-slip faults (trending NW-SE) in NW Iran, that trends from Sofian to Bostan Abad. Generally, the fault consists of two main fault segments. In present research, to study the last active tectonics at the North Tabriz Fault More

The North Tabriz Fault is one of the major strike-slip faults (trending NW-SE) in NW Iran, that trends from Sofian to Bostan Abad. Generally, the fault consists of two main fault segments. In present research, to study the last active tectonics at the North Tabriz Fault region, evaluated young morphotectonical features and paleoseismology of northwestern fault segment evaluated. On the basis of morphotectonic approaches on this region, horizontal slip last event (MW = 7.4, 1780 AD) are found in the ranges 3.5 ±0.5 m and vertical slip between 0 and 0.5 m. However, by attention to H/V ratio can propose that NW segment of North Tabriz Fault act as pure strike slip which confirm by new GPS data on this part of Iran. On the basis of paleoseismological researchs, by examining a wall perpendicular to the North Tabriz Fault in North Sahlan Village, four old paleoearthquakes with relative magnitude of MW = 6.4 has been detected. A young magnitude of the event, recorded in deposits of the paleoseismologic trench of the study area, close to 7 have been estimated that according to geographic and stratigraphic location, this event can be associated with historical earthquakes since 1780 AD (MW = 7.4). Manuscript profile

Open Access Article

5 - Seismic hazard assessment of the city of Khoy using deterministic and probabilistic seismic hazard analysis approaches
Nasim Rahmani Abasfam

Construction of new cities or development of old towns in an area requires geological and geophysical (seismic) studies. The city of Khoy is one of the developing cities that have to be study. Therefore, the Deterministic and Probabilistic Seismic Hazard Analysis (DSHA More

Construction of new cities or development of old towns in an area requires geological and geophysical (seismic) studies. The city of Khoy is one of the developing cities that have to be study. Therefore, the Deterministic and Probabilistic Seismic Hazard Analysis (DSHA and PSHA) approaches have been used to assess seismic hazards and earthquake risk in the city. For this purpose, analyses have been carried out considering historic and instrumented earthquakes, geologic and seismotectonic parameters of the region covering a radius of 100 km with the city of Khoy in the center. Therefore, the main faults and fault zones in the study area were studied and length and distance of each fault from the center of the city of Khoy was calculated. At the next step, the Maximum Credible Earthquake (MCE) and Peak Ground Acceleration (PGA) have been measured using both DSHA and PSHA approaches and also equations presented by different researchers. DSHA Results show that the MCE and PGA values are 6.5 and 0.31g, respectively. PSHA results indicated that the MCE evaluated value is 6.1 for a 0.64 probability in a 50-years period. The period of this earthquake is 110 years and its probability will be 0.009 per a year. The occurrence probability of earthquakes with magnitude equal or greater than 7.1 is 10% and for earthquakes with magnitude equal or greater than 6.3 is 50% for the study area. Manuscript profile

Open Access Article

6 - Determination of stress state and tectonic regime changes in the brittle structures of Chah Yusuf Mountain (East of Gonabad)
فرهاد زارعی Ghaemi Ghaemi

In this study, structural elements, such as faults and fractures and their formation mechanisms and relationships with tectonic regime of Chah Yusuf Mountain in East of Gonabad city have been recognized and discussed. Their relation with regional fractures, based on dat More

In this study, structural elements, such as faults and fractures and their formation mechanisms and relationships with tectonic regime of Chah Yusuf Mountain in East of Gonabad city have been recognized and discussed. Their relation with regional fractures, based on data’s from satellite image process and field data, is also shown. Major faults in this area were identified by using fault plain features such as striations, stretching vein and cumulative steps of minerals that helped us to determine fault mechanisms. In general, faults were oriented in three main directions: 1) Reversed faulting along N90-120˚, 2) Right lateral strike –slip faults along N140-160˚ and 3) Normal faults along N0-15˚. Based on the obtained data and using the inversion method, the orientation of the principal stress axes (σ1، σ2 and σ3) and the ratio of the principal stress differences R in the studied area were analyzed. The results showed two different tectonic regimes in the formation of regional structures: 1) Compressive tectonic regime, major stress along NNE-SSW, which generated structures of folds and reversed faults. 2) Shear tectonic regime, compressive stress along NE_SW and tensile stress line NW-SE, which generated structures such as strike-slip faults, normal faults, vein and tensile fracture. So, the major stress direction in this region is NNE-SSW, which shows its relation to the Late Cenozoic Arabia –Eurasia oblique continental collision. Manuscript profile

Open Access Article

7 - Temporal evolution of faults in Ziaran region, shoutwestern of central Alborz
Elham Asadi Mehmandosti

Ziaran area is located in the southwestern part of the central Alborz range (northern Iran) where a complete series of rocks from Paleozoic to Tertiary are exposed. Thus, the area is suitable for temporal evolution of structures in this part of the range. The study area More

Ziaran area is located in the southwestern part of the central Alborz range (northern Iran) where a complete series of rocks from Paleozoic to Tertiary are exposed. Thus, the area is suitable for temporal evolution of structures in this part of the range. The study area is bounded by the Taleghan Fault to the south, the Tekie Fault to the east, and the Ahurak Fault (Western continuation of the North Qazvin Fault) to the North. In this research, kinematic analysis of these faults and other related structures are presented to elucidate their structural evolution during Tertiary, considering the relationship between present structure and the dominant Tertiary deformation phases. The data obtained from analysis of the Taeghan Fault implies the basement involvement nature of the fault and its evolution during the inversion of an initial normal fault since Late Cretaceous (at least). This inversion led to thrusting of the Paleozoic and Mesozoic rocks over the Eocene units. Based on E-W strikes of the Taleghan and Ahurak faults and their reverse components, it might be suggested that they have been formed as result of a N–S compression phase before the Miocene. During the Miocene, the final collision between the Arabian Plate and Central Iran has occurred (with approximate oblique trend of SSW-NNE). This change of trend resulted in variation on the main faults kinematics across the area such as change in kinematics of the Taleghan Fault to left lateral strike-slip and that of the Ahurak Fault to right lateral strike-slip. Due to SSW motions of the Caspian basin toward the central Iran, left lateral transperssion tectonics have dominant since Pliocene. This movement led to reactivation of the basement faults and their effect have resulted in formation of several left lateral strike slip faults, as its riddle shear faults inside the study area. Manuscript profile

Open Access Article

8 - Morphotectonic study of a fault tip zone around Qozlu (SE part of the North Tabriz fault)
Alireza Yousefi-Bavil Moayyed

Fault traces within the Qozlu fault tip zone, located at the southeast end of a segment of the North Tabriz fault, which reaches to the Bozqush deformation zone, represents the formation of a horsetail structure. There is, however, no information about the type of this More

Fault traces within the Qozlu fault tip zone, located at the southeast end of a segment of the North Tabriz fault, which reaches to the Bozqush deformation zone, represents the formation of a horsetail structure. There is, however, no information about the type of this structure or its deformation pattern. In this regard, study of topography (analysis of the relative elevation difference at two scales—within the overall deformation zone and in buffer zones along streams flowing within the zone), surface slope, asymmetry factor, and geological information indicate that: 1) the fault tip zone is a contractional horsetail splay; 2) a compressional tectonic regime is dominant within the fault tip zone and the trend of maximum compression is N20W-S20E; 3) two different fault zones with maximum and minimum tectonic activities are recognised along two streams within the fault tip zone ; 4) the overall dip-slip component within the stream-related fault zones is reverse or thrust. These results provide significant information about tectonics of the Qozlu fault tip zone and improve our knowledge of deformation within the North Tabriz fault zone. This study, also, demonstrates the importance of using stream longitudinal swath profiles to obtain tectonic information directly from topography. Manuscript profile

Open Access Article

9 - Mechanism of young deformation in Tehran plain: a combination of field observation and analog modeling
Hourieh AliBeygi Morteza Talebian Manouchehr Ghoreshi

The capital city of Tehran is located to the south of central Alborz. The North Tehran fault, as the main structure of this region, perched on the northern part of the city and separate alluvial fans from volcanic rocks of the Alborz. There are several other faults w More

The capital city of Tehran is located to the south of central Alborz. The North Tehran fault, as the main structure of this region, perched on the northern part of the city and separate alluvial fans from volcanic rocks of the Alborz. There are several other faults within the city which seem to be structurally related to the North Tehran fault. Geomorphic study of fans and river deposits suggest that most of these faults are active and taking up both left-lateral and shortening in a wider zone to the south of North Tehran fault. In addition to faults there is distinct folding within the Tehran plain. Field observation along road cuts which cross these structures suggest that young folding in Tehran plain are active and escalate due to the activities of the underlying faults. There is little evidence of rupture in front of these structures and thus most of them are considered as blind faulting. The trend of these structures is oblique to the North Tehran fault which is probably due to distribution of left lateral deformation in wider zone within the Tehran plain. The distance between active folds and the North Tehran fault increase from west to east. Analog modelings were carried out to study the effect of thickness and slop of deposits on position and trend of structures within the Tehran plain. Results from these experiences show that geometry, orientation and distance between structures is probably controlled by oblique shortening of the zone, as well as increase in thickness and slope of the sedimentary deposits. Manuscript profile

Open Access Article

10 - The Impacts of the North Tabriz Fault on the quantitative and qualitative characteristics of the neighbor aquifer in the East of Tabriz City, Iran
ebrahim rajabpour Abdorreza Vaezi hir

The North Tabriz Fault (NTF) is the most prominent tectonic structure in the Northwest of Iran. The results of this study show that this fault has a major impact on hydrogeological conditions of the local aquifer. Plio-Quaternary volcanic ash and tuff layers constitute More

The North Tabriz Fault (NTF) is the most prominent tectonic structure in the Northwest of Iran. The results of this study show that this fault has a major impact on hydrogeological conditions of the local aquifer. Plio-Quaternary volcanic ash and tuff layers constitute the only unconfined aquifer of this area which directly lies on Miocene red marl as aquifer bed rock. Northern part aquifer bed rock is placed in the higher level than the southern part. This could be the reason for the existence of the reverse dip-slip movement of fault in this area, which causes the northern part (hanging wall) trust over the southern part (footwall). Sharp differences in aquifer bed rock level at relatively low distances (less than 200 m), can be a sign of near-vertical slope of fault in this area. An obvious groundwater level differences which reaches to more than 8 meters, along with the apparent differences between groundwater qualities across the fault at a low distance (about 200 meters) show a barrier behavior of fault. Total depth of the southern part wells is four times compared to the northern parts. Total annual discharge of southern part wells is about eight times of northern parts. Total hardness and ions concentrations of groundwater samples shows that most of the northern part samples are not suitable for drinking purposes, but the southern part samples are suitable. Also, all of the northern part samples have the negative Langelier index (corrosive). All of the southern part samples have the positive (very close to zero) Langelier index and suitable for industrial usages. Therefore this is a reason why most of industries in this area were located in the southern part of the fault. Manuscript profile

Open Access Article

11 - Analysis of structural relation between Hatamabad Syncline and Dasht-e-Bayaz active fault, North of Qayen - East of Iran.
Morteza gholchin Morteza Elahpour Mahmoureza Heyhat Mohammahdi Khatib

Hatamabad syncline is located 40 km north of Qayen and with an area of more than 190 km2. In this study, the geometric - kinematic analysis of this syncline was assessed to understand the genetic relation between this structure and Dasht-e-Bayaz active fault. Hatamabad More

Hatamabad syncline is located 40 km north of Qayen and with an area of more than 190 km2. In this study, the geometric - kinematic analysis of this syncline was assessed to understand the genetic relation between this structure and Dasht-e-Bayaz active fault. Hatamabad syncline is situated in Dasht-e-Bayaz fault segmentations gap and its S shape is the result of a sinisteral strike slip movement, raised a lot of questions about the effect of Dasht-e-Bayaz sinisteral fault. Geometric analysis of structural cross sections, determine maximum strain trend 221 or 41 degrees for the Hatamabad syncline. This shows good correlation with stress trend of Dasht-e-Bayaz fault. In addition mechanism of Mohammad Abad -e- Alam fault along with its stress trend 217 or 37 degrees that is obtained by right dihedral method, proves S- shape of Hatamabad syncline. Finally the Hatamabad syncline was deformed due to its location in a sinisteral transpression zone between Dasht-e-Bayaz sinisteral fault with a reverse parameter and Mohammad Abad -e- Alam reverse fault with sinisteral strike slip component. Manuscript profile

Open Access Article

12 - Assessment of the activity in the gap zone of the Rudbar Fault, based on the morphotectonic indices of the Sefidrud River, Gilan Province
Shoja Ansari

In this study the morphotectonic indices for a specified length of the Sefidrud River, which is located in the meizoseismal area of the 1990 Rudbar earthquake, have been investigated to constrain the activity of a gap between the Rudbar Fault segments. The Digital Eleva More

In this study the morphotectonic indices for a specified length of the Sefidrud River, which is located in the meizoseismal area of the 1990 Rudbar earthquake, have been investigated to constrain the activity of a gap between the Rudbar Fault segments. The Digital Elevation Model (DEM) with 30 m resolution was used to obtain the elevation data. Fifteen km of the Sefidrud River also was divided into 100 -meter segments to calculate the morphotectonic indices. The morphotectonic indices include the sinuosity (SI), stream-length gradient (SL) and river long profile. The sinuosity in this region, where the trend of the Rudbar fault cut across the river, is approximately 1-1.5 and has a lower value relative to the other segments of the river. This indicates that the uplift possibly affected this region and then indicates the high tectonic activity. The stream-length gradient in the target region is approximately >3000 and has a higher value in the region which may be related to the lithological and active tectonic effects. The high value of SL can be used for determining the regions with high potential for the landslides along the strike of the Sefidrud River. The Sefidrud long profile, in aforementioned area, has a bulge or convexity. Such convexity together with the high value of stream-length gradient can indicate that the tectonic activities are significant in this region. By comparing the morphotectonic analysis with the seismotectonic studies such as the Coulomb stress changes due to the 1990 Rudbar earthquake, in which the high stress zones were detected in this region, it can be cluded that the studied region has high tectonic activities and consequently its monitoring to prevent the seismic hazard is essential. Manuscript profile

Open Access Article

13 - Experimental modeling of migration in Shekarab active fault system (North Birjand)
Mehdi Yosefi Mohammad Mahdi Khatib Ebrahim Gholami

The Shekarab fault system, located in the north of the Birjand city, has fault scarps parallel to main fault. Due to the structural features, mechanism of fault trends in the region, fault-related folding and the occurrence of the migration from the north to the south a More

The Shekarab fault system, located in the north of the Birjand city, has fault scarps parallel to main fault. Due to the structural features, mechanism of fault trends in the region, fault-related folding and the occurrence of the migration from the north to the south at Shekarab fault, modeling is done for the geometric pattern of the fault propagation, which is in accordance with the Shekarab fault zone. In this model, new scarps are formed in the footwall of the previous scarps. According to the results of modeling, the most important factor for creating alternate scarps is the north-south compression in the Shekarab thrust. At each step, by increasing the amount of shortening, the emergence of new faults are observed so that the first thrust is created on the northern side of the Shekarab zone and subsequent faults are created by increasing the amount of shortening up to a maximum of 58%, on the southern side of the zone and on the footwall of the previous faults. In this modeling, the slope of the thrusts is created in four stages of shortening varying between 60-65 degrees, which is comparable with the actual slope of the Shekarab faults of 70 degrees. According to the experimental results, the sequence of thrust creation in each modeling stage is consistent with the sequence of thrust in the Shekarab zone and with the north-south migration of the fault. According to the geometry of thrusts and back-thrust, the model of formation of structures in this fault zone is the foreland breaking sequence model so that the branches of the thrust originate from a point. Manuscript profile

Open Access Article

14 - Reconstruction of present-day local stress field affecting the North Tabriz Fault and surrounding areas based on earthquakes focal mechanism by using inversion method
Ahad Noori Behnam Rahimi

In this research, present-day tectonic stress field affecting North Tabriz Fault and surrounding areas was reconstructed by using 37 compiled earthquakes focal mechanism from various sources. Triangle diagrams were used to determine the sense of the earthquakes focal me More

In this research, present-day tectonic stress field affecting North Tabriz Fault and surrounding areas was reconstructed by using 37 compiled earthquakes focal mechanism from various sources. Triangle diagrams were used to determine the sense of the earthquakes focal mechanism. The sense of these data varies from strike-slip to thrust regime. Stress separation process was applied on data set for separation of the various tectonics regimes from a poly-phase system to obtain reduced stress tensors. This was done because most of the data participated in them and reconstructed stress fields completely cover the stresses affecting the region. The results of inversion analysis and internal separation of the data set show three stress regimes acting in this region. Considerably, all three stress regimes have a horizontal pressure stress with NW-SE to NNW-SSE trend. The direction of maximum pressure in each first, second and third regimes is 09/329, 28/310 and 03/138, respectively. In this research, present-day tectonic stress field affecting North Tabriz Fault and surrounding areas was reconstructed by using 37 compiled earthquakes focal mechanism from various sources. Triangle diagrams were used to determine the sense of the earthquakes focal mechanism. The sense of these data varies from strike-slip to thrust regime. Stress separation process was applied on data set for separation of the various tectonics regimes from a poly-phase system to obtain reduced stress tensors. This was done because most of the data participated in them and reconstructed stress fields completely cover the stresses affecting the region. The results of inversion analysis and internal separation of the data set show three stress regimes acting in this region. Considerably, all three stress regimes have a horizontal pressure stress with NW-SE to NNW-SSE trend. The direction of maximum pressure in each first, second and third regimes is 09/329, 28/310 and 03/138, respectively. Manuscript profile

Open Access Article

15 - Segmentation of Shotori fault using structural, geomorphology, seismicity and fractaly analysis

Shotori active fault zone (in the northern end of Nayband fault) has a dextral strike-slip mechanism with a revers component. Landsat image studies show that this fault is uncontinuous and segmented. In this research, based on fault geometric discontinuity, two segments More

Shotori active fault zone (in the northern end of Nayband fault) has a dextral strike-slip mechanism with a revers component. Landsat image studies show that this fault is uncontinuous and segmented. In this research, based on fault geometric discontinuity, two segments, were determined on both the northern (with trend of N40w) and southern segments (with trend of N20w). Both of them are reverse with a right lateral slip movement component. The southern segment is the most active segment, based on fractal earthquake and fractal fractures (Ds= 1/60, DN=1/73) and earthquakes (Ds=0/43, DN=0/68) morphotectonic¬ parameters such as river slope indicator (SLs=1703/27,SLN=1526/7), sinuosity river channel (SS=1/24,SN=1/27), the V ratio (Vs=0/7,VN=0/9) and structural and seismic data. The most frequent recorded earthquakes and the biggest registered earthquake with a magnitude of 7.4 on the Richter scale have taken place in the southern segment. This indicates a high potential of seismic activity on this segment of the Shotori fault. Manuscript profile

Open Access Article

16 - Ore-forming fluid source and effective parameters in the gold deposition at the Dashkasan deposit (NE Qorveh): structure, microthermometry and O-H stable isotopic evidences
Mohammad Moradi zahra Alaminia Ebrahim Tale Fazel Reza Alipoor

The Takab-Qorveh magmatic lineament between the Urumieh-Dokhtar and the Sanandaj-Sirjan zones contains important gold mines such as Dashkasan and Zarshuran. The Dashkasan deposit is located in the Kurdistan province and is one of the largest gold deposits in the Middle More

The Takab-Qorveh magmatic lineament between the Urumieh-Dokhtar and the Sanandaj-Sirjan zones contains important gold mines such as Dashkasan and Zarshuran. The Dashkasan deposit is located in the Kurdistan province and is one of the largest gold deposits in the Middle East domain. The gold is mainly hosted by porphyritic dacite and breccia. In spite of detailed previous studies, there is still debate regarding the genesis of the Dashkasan. Herein, this study present the source and evolution of the mineralizing fluids using the fluid inclusion and stable isotopic investigations. At Dashkasan, the breccia and mineralization are constrained by the steep NNE-SSW-trending faults. Alteration zones on the surface are phyllic, silicification, tourmalinization, argillic and minor propylitic. Sulfide minerals consist of pyrite, marcasite, arseno-pyrite, stibnite, chalcopyrite and to lesser amounts of bornite, sphalerite and galena associated with quartz, tourmaline, sericite, calcite and chalcedony. Result of microthermometry measurements shows a range of homogenization temperatures between 183-260 °C with salinities of 15.97 to 17.06 wt % NaCl equiv. The oxygen isotope composition of fluid in quartz ranges from 6.6 to 9.9 ‰, while, the tourmaline has δ18Oﬂuid values are in the ranges of 8.5 to 12.3‰. Also, the δDﬂuid values of the quartz and tourmaline ranges between -51 to -81 and -93 to -111‰, respectively. Integrating with previous studies, all these data, suggest a migration from a porphyry gold system (stage-I) with a magmatic source to a low-sulphidation epithermal (stage-III). Stage-II occurred simultaneously with the collapse and eruption of crater. Manuscript profile

Open Access Article

17 - Evidence for development of transpressional duplex in the west of Shahroud- eastern Alborz
Ali Radfar Aziz Rahimi

The study area is located in the southern boundary of the Eastern Alborz range between North Shahroud Fault and Astaneh Fault. The exposed formations are from Paleozoic to Cenozoic in age. Several structural surveys such as geometrical analysis of folds and geometrical More

The study area is located in the southern boundary of the Eastern Alborz range between North Shahroud Fault and Astaneh Fault. The exposed formations are from Paleozoic to Cenozoic in age. Several structural surveys such as geometrical analysis of folds and geometrical and kinematical analysis of faults were studied. Field observations and software analysis revealed that most folded structures show a northeast-southwest trend in the eastern area and an east-west axis in the western area. Due to location of E-W trending mesoscopic folds on the hanging-wall of Tazareh thrust fault, these mesoscopic folds are fault-related folds. Axes and axial plane of folds revealed that macroscopic folds with a tendency toward south-east, are consistent with flower structure of the Alborz range. Available faults in the area have two trends: northeast-southwest in the eastern part and east-west trend in the western area, and their arrangements give a scaly situation to the area. Therefore, due to existence of east-west compressional structures, it could be suggested that Dehmolla contractional duplex is developed as a result of strike-slip faulting between Shahroud and Astaneh faults. Manuscript profile

Open Access Article

18 - Investigating rate of Doroud fault zone tectonic activity (southwest of Iran) by using geomorphologic data analysis (fans, basins and drainage system)
محمدرضا سپهوند Zahra Kamali Tokhmechi MahmoudReza Hayhat Roshandel Kahoo Hamid Nazari Ahmadi Noubari Mohammad Mahdi Khatib

Morphotectonic analysis with the help of geomorphic indices is considered as a tool for the identification of new and active structures affected by tectonic movements in special areas. For this purpose, indicators such as Mountain Front Sinuosity index (Smf), (Vf), (Af More

Morphotectonic analysis with the help of geomorphic indices is considered as a tool for the identification of new and active structures affected by tectonic movements in special areas. For this purpose, indicators such as Mountain Front Sinuosity index (Smf), (Vf), (Af), (S), (Sl), (T), form factor basin, basin shape, slenderness ratio and stretch ratio index of basin (Bs) associated with alluvial fans, including fan of bending β, fanning coefficient and longitudinal profile were calculated. The tools in this study include: the topographic maps, field geology invesigations, satellite imagery, digital elevation model (DEM), IRS satellite images of the region, GIS and Global mapper softwares. The results of the analysis of topographic data, evidences from field observations and data obtained from geomorphic indicators, all suggested that the area is active from neotectonics viewpoint. Based on the classification of LAT, the study area is classified in class 1, which indicates intense tectonic activity. Based on the results, the northern part of the Dorud fault is more active than the southern section in terms of neotectonic movements. Manuscript profile

Open Access Article

19 - Determining paleo-stress based on the study of discontinuities and folds in Zagros Collision Zone; Case Study: Kermanshah Region
سپیده رضابیک عبدالله سعیدی Mehran Aryan علی سربی

20.1001.1.17357128.1400.15.57.5.7

The studied zone is in the Northern part of Zagros Suture Zone (Kermanshah). The presence of deep sea sediments, oceanic crust remnants, platform carbonates, igneous and metamorphosed rocks of active margin and carbonate sequence of passive margin that are assembled in More

The studied zone is in the Northern part of Zagros Suture Zone (Kermanshah). The presence of deep sea sediments, oceanic crust remnants, platform carbonates, igneous and metamorphosed rocks of active margin and carbonate sequence of passive margin that are assembled in the studied area show a compressional tectonic regime from the late Cretaceous up to the present. As a result of convergent regime, a very complicated structural zone is developed. The main purpose of this study is stress characteristic analysis in Zagros Suture Zone (Kermanshah).To recognize and study the arrangement of stress axes a great amount of data were gathered from the folds axial surface and 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. The stress recording patterns for data in this study is Multiple Inverse Method and comparison with stress position by using folds axial surface. By studying folds it was obtained the situation of main stress σ1, σ2 and σ3 respectively as 029, 127, 234 and by using the method Multiple Inverse Method, the situation of main stress is obtained as 059, 304, 194. Based on the investigations in the study area and measurements on Cretaceous rocks, the results show that the main stress direction since Cretaceous up to the present is northeastern with minor changes. The estimations of stress direction were the same in both folds and faults. As a result, the shortening direction has been constant, so the shortening faults all show one direction of stress. Manuscript profile

Open Access Article

20 - Morphotectonic investigation of Talkhab and Tozlugol faults and formation of the Meyghan playa, Arak
leili Izadi kian نسرین پیری محمدجواد اکبری Masomeh Molaei

20.1001.1.17357128.1400.15.58.7.1

Meyghan playa near Arak city is located at the boundary of the metamorphic zone of Sanandaj- Sirjan and Urmia-Bazman volcanic zone. Two main faults of Talkhab and Tozlugol (Tabarte) play a key role in the formation of this basin by right lateral movement with northwest More

Meyghan playa near Arak city is located at the boundary of the metamorphic zone of Sanandaj- Sirjan and Urmia-Bazman volcanic zone. Two main faults of Talkhab and Tozlugol (Tabarte) play a key role in the formation of this basin by right lateral movement with northwest - southeast trend. In this study, morphotectonic indices were investigated to study the tectonic activity of these two faults. The measured indices include altimeter integral index, asymmetry index, stream length gradient index and basin shape factor. Investigating the relative active tectonics using the above mentioned indicators shows that Arak region has a relatively moderate to high activity. Particularly, the region between the two Talkhab and Tozlugol faults is more active than the other regions. The graben of the Meyghan Desert is formed due to the activity of the Takhab and Thouzlugol faults during the Pleistocene by right lateral transpresion zone. The southwestern side of the lake is in accordance with the Tozlugol fault. It seems that according to the morphometric studies of this area, the activity of the Talkhab fault is more than the Tozlugol fault and plays an important role in the formation of the Meyghan playa. Manuscript profile

Open Access Article

21 - Investigation of structural pattern and introduction of detachment surface of Alborz Mountain Range in the north of Damghan
Z. Taslimi A. Saidi M. Ghoreshi M. Aryan A. Solgi

20.1001.1.17357128.1401.16.61.6.3

The studied area is a part of Eastern central Alborz, bestween southeastern piedmont of Alborz (NW of Damghan) and North Alborz Fault (South of Sari). The Alborz Mountain range which forms the heights of northern territory, separated the Caspian Depression from Iran cen More

The studied area is a part of Eastern central Alborz, bestween southeastern piedmont of Alborz (NW of Damghan) and North Alborz Fault (South of Sari). The Alborz Mountain range which forms the heights of northern territory, separated the Caspian Depression from Iran central plateau. The Alborz is one of the Iranian mountain ranges that were deformed during two Cimmerian and Alpine organic events. This deformation is continued until the present day. This research is based on the satellite images, field investigations, drawing structural sections, stratigraphic sequences from the folded and thrusted parts of Alborz Mountains. The studied area is composed of numerous anticlines and synclines from South to North as Tuyeh- Darvar anticline, Sabour anticline, Talma- Darreh anticline, Alikhani syncline, Tarkan anticline, Babr cheshmeh syncline and anticline. Some of these folds are related to faulting which occured due to the typical continuous shortening and faulting of Alborz crust and destroyed their original patterns. The function of main faults and specially thrust faults played an essential role on the present models of mentioned folds. Regarding the axes of the folds, the effective compression over the area has a North, North Waste-South, South-East direction. This direction is perpendicular to axial trend of folds. The physico-mechanical properties of Alborz geological units caused development of detachment surfaces on main faults. The shortening intensity and large displacements have led to disappearance of a limb or whole fold. In this study the three surfaces of detachment were introduced inside the stratigraphic sequences from Precambrian to middle Eocene based on the well-known and documented data. Manuscript profile

Open Access Article

22 - Exploration analysis and determining the relationship between mineralization and faults as a new exploration key in the Sirjan-Beshneh copper deposit
Reza Ahmadi S.J. Hosseini Shahraki

20.1001.1.17357128.1401.16.63.5.6

Sirjan-Beshneh copper deposit with 0.5 kilometer area is located in Kerman province 80 kilometers west of Sirjan city. The variety of exploration activities including remote-sensing, field traverses, geophysical explorations, surface explorations comprising surface samp More

Sirjan-Beshneh copper deposit with 0.5 kilometer area is located in Kerman province 80 kilometers west of Sirjan city. The variety of exploration activities including remote-sensing, field traverses, geophysical explorations, surface explorations comprising surface sampling and geochemical analysis of 94 samples, drilling and surveying three trenches with sampling and analysis of six samples as well as drilling of eight deep exploration borehole with the total length of 414.5 meter, have been carried out in the metallic deposit. All faults in the region were mapped based on the remote-sensing and structural geology operations of the region. In the present research, all exploration activities carried out in the Beshneh copper deposit were analyzed through investigating their relationship with the faults in the region. To achieve this goal, various techniques including drawing rose-diagram of faults, processing of resistivity and chargeability data of rectangle survey and smoothed inversion of data for five dipole-dipole profiles, imaging isograde maps for the surface and trench samples as well as 3-D modeling of exploration boreholes assays of the region were employed. The results showed that locations of mineralization related to the fractures and faults present in the region since the trend of most mineralized veins is along the main faults. At the end, in order to complete the explorations of the previous stages to get a better recognition of the deposit, drilling of several new exploration boreholes was proposed based on all performed studies and integrating obtained results as an exploration key.. Manuscript profile

Open Access Article

23 - Structural evolution of the southern Natanz region and its role in the distribution and concentration of Pb-Zn mineralization
Firouzeh Shavvakhi Saeed Madanipour M. Tadayon Ebrahim Rastad M.J. Kupaei

20.1001.1.17357128.1401.16.64.7.0

The studied area is structurally located in the western part of the Central Iranian structural zone atthe southwestern termination of the Qom-Zefreh Fault. Our structural data represent the older generation of E-W to NW-SE trending thrust faults that juxtapose Permia More

The studied area is structurally located in the western part of the Central Iranian structural zone atthe southwestern termination of the Qom-Zefreh Fault. Our structural data represent the older generation of E-W to NW-SE trending thrust faults that juxtapose Permian- Triassic (Nayband and Shotori Formations) over younger rock units. Most of the thrust faults have been crossed cut with the younger generation of the strike-slip fault system. Major thrust faulting of the area occurred during post Late Cretaceous time. The final post Oligocene strike slip faulting related to the activation of the Qom- Zefreh fault overprinted and crossed cut older structural features. Our economic geological studies in the south Natanz area represent syngeneic strati bond or Sedex-Like type Pb-Zn epigenetic occurrence of these deposits in Permian-Triassic carbonates and barite developed in the Lower Cretaceous carbonate and clastics. The ore deposit development in Permian-Triassic Carbonates have occurred along thrust faults and then redistributed along strike slip faults with normal component. Therefore, genetically, stratiform deposits developed in the Lower Cretaceous carbonates and clastics (Yazdan and Pinavand Ore deposit) occurred in a regional early Cretaceous extensional regime. However, epigenetic deposits developed in Permian-Triassic carbonates (Changarzeh deposit) were generated during the regional post Late Cretaceous compressional regime and redistributed during post Oligocene strike slip deformation. Manuscript profile

Open Access Article

24 - Investigation of tectonics, fault data and their relationship with mineralization and alteration in Asbkhan, Heris area (East Azerbaijan Province - Northwest Iran)
N. Yadegari Seyed Ghafor Alavi Mohsen Moayyed

20.1001.1.17357128.1402.17.65.3.5

The study area is located in the south of Qushadagh mountain range, in the north of Asbkhan village, Heris township and in East Azarbaijan province. In terms of structural geology of Iran, this area is located in the main zone of Central Iran and Alborz-Azerbaijan sub-z More

The study area is located in the south of Qushadagh mountain range, in the north of Asbkhan village, Heris township and in East Azarbaijan province. In terms of structural geology of Iran, this area is located in the main zone of Central Iran and Alborz-Azerbaijan sub-zone. The geological units of the region are including Eocene igneous and pyroclastic rocks with combination of andesitic, Trachyandesitic, basaltic, tuffic and ignembritic. The semi-deep intrusive mass with Oligocene age, with the combination of quartz diorite, diorite and quartz monzonite in the form of stock and dyke is exposed in the area. Structural studies, including fault plates, slickenside on them, and the joints system in various lithologies, indicate at least two general stress directions in the range, Which can be created following one tectonic regime or two tectonic regimes. If we consider the tectonic regime as a phase and consider the tensors with different directions as the result of rotation in the fault plates, We can introduce a general strike-slip regime with a general north-south trend that controls the existing structures of the region. At the same time, the infiltration of intrusive masses has caused the disintegration of these structures and made the issue more complicated. In general, faults with a northwest-southeast trend and a right on strike-slip mechanism, form the main structures of the area.Other faults are controlled by the main structures following the Riddle fractures system. Based on the system of joints in four different lithologies, lithological units from old to new include: basaltic andesite, quartz diorite, quartz monzonite (porphyry mass) and diorite, which from old to new reduces the diversity of the joints system. The northwest-southeast tectonic system has been involved in the development of argillic alteration and the northeast-southwest system has been important in the development of siliceous and mineralized veins. Manuscript profile

Open Access Article

25 - Balanced Cross Sections and Determine of Shortening in North Makran Ophiolite Mélange, Southeastern Iran
Azizollah Tajvar Mohammad Mahdi Khatib Mohamad Hossian Zarinkoub

The geometrical and kinematic characteristics of structural elements of north Makran have been measured and analyzed in five structural sections. Then, by using of balance cross sections and restoring the structures to their original state, the amount of shortening has More

The geometrical and kinematic characteristics of structural elements of north Makran have been measured and analyzed in five structural sections. Then, by using of balance cross sections and restoring the structures to their original state, the amount of shortening has been determined in different parts of the area. The Bashagard, Dranar, Abenma, Koh Bahark and Vernach thrust faults with a WNW-ESE trend and 20 to 35 degrees dip towards the NNE are the main deformation controllers in this region and are the main cause of shortening. The excellent fit between N209/09 principal stress axis calculated based on the geometry of thrust faults and compression axis that formed folds, indicates that these structures were formed as a result of the same tectonic regime. The difference in the amount of shortening in different parts of the north Makran ophiolite mélange of is also directly related to the thrust faults. So that, in western part of north Makran, thrust faults caused shortening amount 22.66, 22.85 and 14.32% in structural sections A-A', B-B' and C-C' respectively,. In the eastern parts, due to the lack of thrust faults and the presence of more strike-slip faults, the amount of shortening has decreased to 4.52% and 6.67%, respectively, in the sections D-D' and E-E'. Balanced cross sections and restoring the structures to the pre-deformation stages represent the narrow width of the early oceanic basin in the north of Makran. Manuscript profile

Open Access Article

26 - Investigating the geometry and mechanism of folding in Sulabder anticline (SW Iran)
Mehdi Yosefi F. Esfahani Seyd Morteza Moussavi

Calculating the amount of shortening, the angle between ridges, the slope of the main thrust and the percentage of thinning of the front ridge compared to the back ridge in the middle and northwestern parts of Sulabder anticline shows the folding style related to fault More

Calculating the amount of shortening, the angle between ridges, the slope of the main thrust and the percentage of thinning of the front ridge compared to the back ridge in the middle and northwestern parts of Sulabder anticline shows the folding style related to fault propagation in these parts. The calculation of these geometrical parameters in the south-eastern part of the Sulabder anticline also shows the faulted detachment folding style. The change of folding class from 1c to 2 and 3, as well as the change of fold style from detachment folds to fault propagation style, are a sign of increased shortening, deformation progress and evolution of folding from the south-eastern part. This represents that in the initial stage the thrust fault system belongs to the middle and north-western parts, which are in the developed stages of the thrust fault system. The interpretation of seismic sections perpendicular to the Sulabder anticline in different sections shows that the Sulabder anticline in a raised wedge form is higher than the adjacent structures due to the action of the thrust faults on the northern and southern edges. In the Solabdar anticline, the performance and mobile behavior of marl-shale units of Pabdeh and Gurpi formations, due to its high thickness and formable rheology as an intermediate separation horizon, create different folding styles at the top and bottom of this unit. It also caused displacement in the axis of the upper and deeper parts of anticlines. Manuscript profile

Open Access Article

27 - Investigation of the relationship between tectonic morphological indices and seismic acceleration in Indes, Aipak, Avaj and Kushk-e-Nusrat fault zones (northwest of Saveh)
bahar Rezaei nahal Mohsen Pourkermani M. Zare M. Dehbozorgi R. Nozaem

The northwest zone of Saveh city is located in the Indes, Kooshk e Nosrat, Avaj, and Aipak fault zones. Indes, Kooshk e Nosrat, Avaj, and Aipak faults are considered the major faults in central Iran, which are also active in the Quaternary, and their last movements are More

The northwest zone of Saveh city is located in the Indes, Kooshk e Nosrat, Avaj, and Aipak fault zones. Indes, Kooshk e Nosrat, Avaj, and Aipak faults are considered the major faults in central Iran, which are also active in the Quaternary, and their last movements are attributed to the present time. Therefore, the estimation of morphometry to identify the effect of active tectonics on the tectonic evolution of drainage basins seems necessary. In this study, six important morphotectonic indices were analyzed including the longitudinal gradient of the river, asymmetry of the drainage basin, hypsometric integral, drainage basin shape, the ratio of the floor width to the valley height, and mountain front. To model the formation of basins in the studied area, Arc Hydro software (Arc GIS add-ins) was used based on data derived from a digital elevation model. Then, 6 morphotectonic indices were compiled and classified on each of the basins. Finally, the Active Tectonic Index (IAT) was calculated, according to which the study area was classified into 4 categories including very high, high, intermediate, and low tectonic activity. According to the IAT index, 5% of the study area shows very high tectonic activity, 25% of the studied area has high tectonic activity, 65% of it has average tectonic activity and about 5% of the tectonic activity is low. Moreover, seismic acceleration was prepared to confirm the result of morphological indices in the estimation and analysis of active tectonics in the region. In this study, the highest level of tectonic activity can be seen in the north-eastern part of the area. In most sectors, the level of activity is high and intermediate, which is related to the activity of Kooshk-e-Nosrat, Aipak, and Avaj faults. Manuscript profile

Open Access Article

28 - A new look at the rotation of Central Iran: A case study of the Anar fault, east block of the Yazd
Hamidreza AfkhamiArdakani farzin ghaemi Fariba Kargaran Bafghi Ahad Nouri

The Anar fault in the east of Yazd city, with a north-northwest-south-southeast strike, is a basement fault that separates the Yazd block from the Posht Badam block, and its current activity is a dextral strike-slip with a reverse component. The paleostress analysis was More

The Anar fault in the east of Yazd city, with a north-northwest-south-southeast strike, is a basement fault that separates the Yazd block from the Posht Badam block, and its current activity is a dextral strike-slip with a reverse component. The paleostress analysis was done on this fault in order to obtain the tectonic history of central Iran in the period from Devonian to Cretaceous. After analyzing 110 fault data in 13 stations of 2 tectonic phases, it was determined that the maximum stress obtained is between the azimuths of 90 to 110 and 190 to 220 and the angle of stress direction changes in the period from Devonian to Cretaceous is 130 degrees. Based on the studies on the barite veins and the dextral displacements that were seen on them, the separation of the stress phases was done, which indicates that the NNE stress direction is older. Further, according to the previous studies of sedimentology and tectonics in central Iran, it was concluded that the cause of this change in tension was the movement towards the northeast along with the 130 degree counter-clockwise rotation of central Iran. Manuscript profile

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