B Derikvand; S.A Alavi; H Haji ali beigi; I Abdollahie Fard
Abstract
In the Neogene foreland basin of Zagros, Dezful Embayment as a foredeep depozone has accommodated large volumes of deposits of Aghajari and Bakhtiary formations. In this paper, surface and subsurface data and experimental modeling approach have been used to study the effect of these sediments on the ...
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In the Neogene foreland basin of Zagros, Dezful Embayment as a foredeep depozone has accommodated large volumes of deposits of Aghajari and Bakhtiary formations. In this paper, surface and subsurface data and experimental modeling approach have been used to study the effect of these sediments on the geometry and arrangement of structures in the central part of Zagros fold-thrust belt. The experimental modeling suggests that simultaneous performance of erosion and syntectonics sedimentation prevents deformation propagation to the foreland, and rather concentrates it on the structures already formed toward the hinterland. In this regard, anticlines formed toward the hinterland respond to this process by uplift, faulting and limb rotations. With shortening progress, a large-scale anticline is developed toward the foreland after syntectonic sedimentation. Based on experimental modeling, the clastic deposits of Aghajari and Bakhtiary formations in the Dezful Embayment have led to the concentration of deformation expressed as steep to overturned anticlinal limbs and thrust fault developments in the southern parts of the Izeh and Lurestan zones. Also, large volumes of these sediments in the middle part of the Dezful Embayment has prevented formation of large anticlines in this part and caused formation of anticlines in the north and south parts of the Dezful Embayment.
B Derikvand; A Yassaghi
Abstract
The folding style analysis is one of the initial investigations on hydrocarbon reservoirs anticlines. Nader Anticline is located in the western part of the Eastern Kopeh Dagh zone and on hanging wall of the North Kopeh Dagh Reverse Fault. The structural analysis of the anticline is carried out along ...
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The folding style analysis is one of the initial investigations on hydrocarbon reservoirs anticlines. Nader Anticline is located in the western part of the Eastern Kopeh Dagh zone and on hanging wall of the North Kopeh Dagh Reverse Fault. The structural analysis of the anticline is carried out along eight structural transects across the fold. This analysis showed that the Nader Anticline has two culminations with an en echelon arrangement. These culminations as well as the other folds in the study area are cross cut by a series of NW- and N- trending strike-slip faults. The Nader Anticline first culmination is analyzed as fault propagation fold geometry, while its second culmination is examined as fault detachment fold geometry. Since the Nader Hidden Fault cuts the north limb of the first culmination; the geometry of this culmination can also be considered as faulted detachment fold. The study area faults though have different trends but they dominantly have strike-slip mechanism or strike-slip component and thus, can be considered as Riddle shear faults. Geometric and kinematic analysis of these faults showed that a series of these faults could be considered as shear fractures related to a NW-trending PDZ, while the other faults can be examined as Riddle shears related to a N-trending PDZ. Such development of the Riddle shears faults as well as en echelon arrangement of the Nader Anticline culminations imply that the study area is structurally evolved during a NW-trending oblique-slip fault system more likely related to transpressional activity of the North Kopeh Dagh Reverse fault zone.
