Tectonics
E. Haji; H. Safari
Abstract
The Saqqez-Baneh area, as a part of the NW Sanandaj-Sirjan zone, is selected for investigation of different deformation stages. In this research, firstly, the lithology of outcropped rock units and visible lineaments were mapped using remote sensing approach. Then, field surveys were carried out for ...
Read More
The Saqqez-Baneh area, as a part of the NW Sanandaj-Sirjan zone, is selected for investigation of different deformation stages. In this research, firstly, the lithology of outcropped rock units and visible lineaments were mapped using remote sensing approach. Then, field surveys were carried out for structural measurements, during which major and minor faults and shear zones (as ductile zones) were measured and mapped. These data were then entered to GIS environment as vector layers (and attributed descriptions), resulting in preparation of a structural map. The results of field surveys along with geometric and kinematic analyses show that the major faults together with their related fault orders formed a curved shape of structures, outcropped rock unit patterns and intrusive localities. Geometric and kinematic analyses demonstrated three stages of movement: with north-south (in ductile environment), northeast-southwest (in ductile to brittle environment) and east-west (in brittle environment). These three stages caused three stages of faulting with trends along N140-150, N70-80 and N10-20 directions, which can be attributed to three orogenic phases in Precambrian and/or late Triassic (Katangai and/or Cimmerian), Cretaceous (Laramide) and Neogene (late Alpine events such as Savian to Pasadenian).
H Haji Hosseinlou; A Solgi; M Mohajjel; M Pourkermani
Abstract
The Khoy shear zone (KSZ) is exposed 130 Km north of Uremia and 650 km west of Tehran. Structural analysis in the Khoy Shear Zone (KSZ) indicated that they consist of NW-SE oriented various metamorphic rocks. They contain NW-SE trending moderate to steeply dipping mylonitic foliation to the NE. Stretching ...
Read More
The Khoy shear zone (KSZ) is exposed 130 Km north of Uremia and 650 km west of Tehran. Structural analysis in the Khoy Shear Zone (KSZ) indicated that they consist of NW-SE oriented various metamorphic rocks. They contain NW-SE trending moderate to steeply dipping mylonitic foliation to the NE. Stretching lineation plunge shallowly to moderately towards NE. Thrust faults are oriented the same as mylonitic foliation. Ductile fabrics are superimposed by brittle structures. Orientation of the structures indicates that the main stress trend is NE-SW. Four deformation stages (D1-D4) identified in KSZ. The first two stages are ductile that superimposed by the two other ductile-brittle stages. Shear sense indicators such as S/C fabrics, shear bands, shear folds, book-shelf structures, fishes and mantled porphyroclasts indicate that the KSZ deformed via dextral transpression tectonic regime. The Khoy area contains both NW-SE striking dextral strike-slip and SW verging NE dipping ductile reverse shear fabrics. Ductile shear fabrics are overprinted by subsequent younger both thrust and strike-slip fault systems. Abundant syn-tectonic granitoids were intruded in the Khoy area during convergent. The shear deformation fabrics are well identified in both deformed intrusive and metamorphic-ophiolite complex. The geometry and kinematics of shear fabrics indicate a deformation partitioning in both ductile and brittle conditions during a progressive transpression tectonic regime. The KSZ deformed during an oblique convergence scenario between the Arabian and West Alborz- Azerbayjan blocks in NW Iran.
