Authors
1
PhD Student in Tectonics, Faculty of Sciences, Department of Geology, Birjand University, Birjand, Iran
2
Department of geology, Faculty of science, University of Birjand, Birjand, Iran
3
Geology department- Faculty of sciences- University of Birjand
4
Associate Professor of Tectonics, Department of Geology, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan, Iran
Abstract
The study area is located in eastern Iran, north of Zahedan, and from a geological perspective, it lies in the Zand mountainous section of eastern Iran. One of the characteristics of this region is the structural diversity, which indicates a complex tectonic history. To understand the tectonic history and changes in deformation phases in this research, the method of inverse analysis of fault slip data and examination of conjugate faults, structural patterns, and kinematics of folding has been utilized. The analysis of fault kinematic data reveal three stages of change in the principal stress direction (σ1):during the Late Cretaceous(N197°±10°),Neogene (N60°±25°), and Paleogene (N10°±15°). Additionally, the investigation of these three stages of shortening in the region shows trends to the north, east, and northeast. Considering the deformations created and the long-term stress analysis in the region, it can be concluded that this area has experienced three types of deformation. The folding of the first generation is the oldest deformation event, characterized by an east-west axis and related to the pre-collision folding of the Lut and Afghan blocks. The second generation of folding, along with north-south trending faults, occurs during the second deformation event, which coincides with the closure of the Siistan basin in the late Oligocene and aligns with the collision of the Lut and Afghan blocks. After the collision of the Lut and Afghan blocks, the third deformation event follows, characterized by folding of the third generation and conjugate faults with strike-slip motion that disrupt and displace the previous structures.
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