Tectonics
Reza Alipoor; Ali Jahangiri; Zahra Ghasemi
Abstract
The Ghalajeh anticline with about 60 km length and NW-SE trend is located in Lurestan sub-zone and the Zagros fold and thrust belt. Geometry and kinematic of the folds of this zone are controlled by thrust faults and detachment levels. In this research, geometry and deformational style analysis of the ...
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The Ghalajeh anticline with about 60 km length and NW-SE trend is located in Lurestan sub-zone and the Zagros fold and thrust belt. Geometry and kinematic of the folds of this zone are controlled by thrust faults and detachment levels. In this research, geometry and deformational style analysis of the Ghalajeh anticline and the role of the detachment levels on folding style have been investigated interpreting well data and construction of three cross-sections and calculation of geometric parameters. The structure of this anticline is affected by two detachment levels, which include the Pabdeh and Garu formations as the upper and middle detachment levels. Detachment levels and deep-seated and surface thrust faults in the southwestern limb affected the folding geometry and have caused the high thickness of the middle detachment level and inversion of the southern limb which waning southwestern part of the anticline, and the dip of the layers are normal which in turn caused fracturing. Analysis of geometrical parameter along the Ghalajeh anticline indicate that this anticline is an asymmetrical, cylindrical fold is an open half-angle round fold.
A. H. Sadr; Mohammad Mohajjel; A. Yasaghi
Abstract
The style of deformation changes from the hinterland (Sanandaj-Sirjan zone) to the foreland (Zagros) through the Zagros Orogen containing thick-skinned and thin-skinned deformation respectively. NW-SE trending thrust faults dipping to northeast have carried the older rock sequences to the surface. The ...
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The style of deformation changes from the hinterland (Sanandaj-Sirjan zone) to the foreland (Zagros) through the Zagros Orogen containing thick-skinned and thin-skinned deformation respectively. NW-SE trending thrust faults dipping to northeast have carried the older rock sequences to the surface. The Zagros collision zone could be divided into two distinct parts based on deformation mode that is separated by the Main Zagros Thrust. The southwestern part contains imbricate thrust sheets instead, to the northeastern part large amount of shortening is documented by basement deformation with duplex structures. Abundant crystalline deep origin thrust sheets have transported (2 up to 20 km) the metamorphic rock units upon the Zagros suture zone by gravity or tectonic forces. Despite the collision thrust faults, both NW oriented (Main Recent Fault) and NE oriented (named here Azna Fault) basement wrench faults have also activated and caused different style and amount of deformation in the collision zone.