R. Samadi Moghadam; R. Nozaem; M. Dehbozorgi; M. Mohajjel
Abstract
Derenjal Mountains with NE-SW trend, is located in Central Iran, in northwest of Tabas block and in eastern block of Kalmard fault. In this region, the Paleozoic formations (Cambrian to Devonian) have been exposed and surrounded by Neogene and Quaternary deposits. Volcanic rocks of Cambrian limited to ...
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Derenjal Mountains with NE-SW trend, is located in Central Iran, in northwest of Tabas block and in eastern block of Kalmard fault. In this region, the Paleozoic formations (Cambrian to Devonian) have been exposed and surrounded by Neogene and Quaternary deposits. Volcanic rocks of Cambrian limited to Diabasic Rocks Dominated in Kalshaneh Formation and Middle Jurassic (?) lens-shape Andesite massive that covered uncomfortably with Cretaceous non metamorphosed limestone. Kalmard Fault as an old basement and active fault in Central Iran as Principal Displacement Zone (PDZ) and adjacent deformed Deranjal Mountains, have a complex deformation history with respect to rotation of the Compressional Incremental Kinematic Axis during Geological time scale since late Paleozoic to late Cenozoic. Rotation in Central Iran blocks, changing of the convergence direction of Afro-Arabian plate with respect to Iran and also structural interaction between the Central Iran blocks, during tectonic evolutions, imposed the rotation of the Incremental Kinematic Axis (P-T-B) directions with respect to Derenjal Mountains and Kalmard Fault. These process made progressively new structures and also made changes in old structures since post Devonian. In this study, based of Field observation and geometric - kinematic structural Analysis of the more the 150 fault data, the architecture of fault assemblage of Derenjal area demonstrate Synthetic faults (P, R), antithetic faults (X, R’), compression faults (C2) faults and folding in F1 Class in Derenjal Area. These structures represent that the Compressional Incremental Kinematic Axis trend has been changed in anticlockwise direction from perpendicular to parallel with respect to Kalmard Fault since post Devonian to Late Cenozoic and finally superimposition of the strike slip tectonics on the contraction tectonics.
SH. Shafiei Bafti; S.A. Alavi; M. Mohajjel
Abstract
Faryab area at the southeastern part of the Sanandaj-Sirjan zone, containing the Paleozoic rocks in the internal part of Zagros Orogen, displays two folding episodes through a progressive deformation event. Axial planes of recumbent F1 folds dip moderately to the north and the ...
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Faryab area at the southeastern part of the Sanandaj-Sirjan zone, containing the Paleozoic rocks in the internal part of Zagros Orogen, displays two folding episodes through a progressive deformation event. Axial planes of recumbent F1 folds dip moderately to the north and the axes also plunge moderately to NW - SW. F1 folds were generated in a flexural-flow condition in whole lithological units. Thrust faults were produced along the overturned limbs of the F1 folds. These thrusts are most abundant in the central domain, the north of Zartorosht Au-index. At the southern edge of the central domain, displacement of large slabs of calcschist with interbedded marble were produced by these thrust faults.
Overturned limbs were cut by ductile shear zones of thrusts and development of green-schist facies in these shear zones implying the medium dips for thrusting. F2 folds were developed by co-axially refolding of F1 that are well exposed in Pasefid, Zartorosht and Zehmakan anticlines. Structural data shows the variation of F2 axis between S45W - N80W directions. Interference patterns of Z on S, M on S and S on S indicate coaxial refolding F1 by F2 (Hook Type).
