Tectonics
Rojan Hemati; Manouchehr Ghorashi; Ali Solgi; Abdollah Saidi
Abstract
The Zagros suture zone is one of Key regions. Continent - Continent collision between Arabian plate and Iranian Block. This region is coincided by High Zagros and Zagros Simply Fold Zones in Western side and in other side is the Sanandaj- Sirjan Zone. The region of this research in situated in Northern ...
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The Zagros suture zone is one of Key regions. Continent - Continent collision between Arabian plate and Iranian Block. This region is coincided by High Zagros and Zagros Simply Fold Zones in Western side and in other side is the Sanandaj- Sirjan Zone. The region of this research in situated in Northern part of suture zone. The Zagros suture is oriented parallel to the other collision Structures as passive and active margins of Neo- Tethys Basin and also to Magmatic Arc (Urmiyeh - Dokhtar Arc).The main Faults in this region which we can mention by name are Zagros Main Thrust Fault and Zagros Main Recent Fault, Which they are also parallel to others structures. This region of suture zone in highly deformed and structures as folds, faults and nappes are the evident of a long compression Tectonics. The aim of this research firstly is analysing of folds and secondly is calculation of shortening rate of crust in this part of collision Zone. Three structural section (Eslam Abad- e- Gharb - Mahidasht, Kamyaran and Gazorkhani) have been balanced and the rate of shortening which is obtained respectively is 6252m , 6530m and 2040m.
Tectonics
Rojin Hamidi; mohamad reza ghassemi; mohammadreza sheikholeslami
Abstract
Continuation of the compressional regime within the convergence zone between the Central Iran and Turan rigid blocks caused thrusting of old rock complexes over the recent sediments. As a result of multiple thrusts and folds, the area uplifted at the same time and the Binalud range have been shortened. ...
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Continuation of the compressional regime within the convergence zone between the Central Iran and Turan rigid blocks caused thrusting of old rock complexes over the recent sediments. As a result of multiple thrusts and folds, the area uplifted at the same time and the Binalud range have been shortened. This study attempts to evaluate the amount of shortening of the Binalud mountains by reconstruction of a balanced cross-section. Field data from the Dulat-Abad-Neyshbur transect, study of the geological units and décollements along the section, and the Move® software environment are used as the basis for this research. Based on these information, four tests were carried out for balancing the cross section in question. The first test, which used the arc and polygon method for the horizons and a listric fault without floor thrust, failed to display the deformed section. In the second test the section was drawn, however the deformed structure did not balance the section in the process of unfolding the fault bend folds. In the third and fourth tests, we used the kink method to restore the deformed state to an undeformed section. For the third test, deformation was proceeded from the hinterland, and in the process of restoration, a shortening of about 65% was revealed. The fourth test was proceeded from the foreland, and taking into account both the foreland uplifts and shortening, the amount of shortening of Binalud range was estimated to about 26%. The final structural model defined a thin-skinned fold and thrust belt which included fault-bend-folds with out-of-sequence and in sequence duplexes. Major décollement horizons defined in the region include: 1) shale horizons within the Silurian-Devonian rock units, 2) medium-bedded dolomite and limestone layers within the Bahram Formation, and 3) evaporitic layers in the Eocene sediments.
Y Jalili; M.M Khatib; E Gholami; M.R Ghassemi
Abstract
The Chelounak area in northwest of Birjand located in the Sistan suture zone extremity with middle-upper Eocene sedimentary and pyroclastic rocks, folded with different axes and exposed between the Chahak-mosavieh and Mohammadieh-Hessarsangi faults. These folds have a dominant characteristic of the dispersion ...
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The Chelounak area in northwest of Birjand located in the Sistan suture zone extremity with middle-upper Eocene sedimentary and pyroclastic rocks, folded with different axes and exposed between the Chahak-mosavieh and Mohammadieh-Hessarsangi faults. These folds have a dominant characteristic of the dispersion axis trends of NE-SW, NW-SE, and N-S. Geometric-Kinematic Analysis of these folds was carried out by data that taken from the structural interpretations, satellite images, geological maps, structural cross sections and mathematical functions. Aspect ratio, percent shortenings and the rotation folds axes are respectively for folds with NE-SW axis, 0.356-1.6, 20-77% and 28-40°; for folds with NW-SE axes0.352-0.620, 25-41% and 25-40°; and for folds with N-S axes 0.352, 25% and 24°. In this analysis the Chahak and Chelounak synclines and the Chahak anticline with NE-SW axis have maximum shortening and the Shavangan syncline with NW-SE axis has minimum shortening. This Study demonstrated the aspect ratio rises with increasing of shortening. Analysis of the structural elements demonstrates axis change of the Chelounak, Chahak and Hoj noj synclines and the Chahak and Chelounak anticlines with NE-SW Dominant axes affected by the Chahak-Mosavieh fault (~N-S trend) as well as the axis change of the Taj kouh, Shavangan and Hessar sangi synclines with NW-SE dominant axes affected by the Mohammadieh-Hessar sangi fault (~N-S trend). Dispersion of folds axial respect to compressive component has caused difference in aspect ratio, shortening and rotation of fold axes values.
A.N Pourtaghavi; M Pourkermani; G.R Gharabeigli; Sh Sherkati
Abstract
The western part of Kopet Dagh fold belt is located in NE of Iran. The southern half of this belt is located in Iran and the northern half in Turkmenistan. The Kopet Dagh fold belt can be considered as the second important hydrocarbon province of Iran. Sedimentation in this zone began in Middle Jurassic ...
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The western part of Kopet Dagh fold belt is located in NE of Iran. The southern half of this belt is located in Iran and the northern half in Turkmenistan. The Kopet Dagh fold belt can be considered as the second important hydrocarbon province of Iran. Sedimentation in this zone began in Middle Jurassic due to the intercontinental rifting. The Middle Jurassic sediments lay unconformably on the Paleozoic and Triassic sediments. The geometric pattern of the folds has been studied based on the field work, geological maps, and geophysical data. The results show a thick skin deformation with shortening of about 5% during the tectonic inversion caused by the Pasadenian orogeny phase, which governing the deformation of the region.
S. Khederzadeh; A. Bahrodi
Abstract
Sand box models are in order to investigation of circumstance of deformation create in orogenic event. Progressive rigid indenter is as non-plastic continental crust that moves from one side to ward sand hanging wall that is indication plastic crust. The sand primery thickness and angle of rigid indenter ...
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Sand box models are in order to investigation of circumstance of deformation create in orogenic event. Progressive rigid indenter is as non-plastic continental crust that moves from one side to ward sand hanging wall that is indication plastic crust. The sand primery thickness and angle of rigid indenter are changeable. In the all of models, rises sand in the two side of plan of indenter between fore-slop and back-slop, in the top of indenter progressive edge. The formation rate of anticlinorium folds is related to thickness of sand hanging wall, form of progressive and rate of falling's back-slop plan. Change of primery thickness of sand hanging wall is controler of distance and rate of anticlinorium folds formation. The aim of this experimental work is investigation of thrust belts, progressive indenter, and research of effect's slope in the collision zones and fold-thrusts creation, also comparison of experimental model to natural model.
