Deformation style in the northern part of the the Sistan suture zone, Eastern Iran

Document Type : Original Article

Authors

1 Department of geology- faculty of science - university of Birjand - Iran

2 University of Birjand

Abstract

The study area is located in the northeast of the Lut block between Nehbandan and Nayband fault zones; that in addition to sedimentary units and Cretaceous ophiolites, a wide range of Paleogene and Neogene sedimentary facies and pyroclastic sediments have been affected by deformation. Structural trends of the study area include two main groups with north-south and northwest-southeast trends. Structural data were collected in the direction of north-south trends (including Gazik, Afzalabad and east of Sahlabad) and northwest-southeast (including Birjand and Zahan); the deformed regions can be divided into three groups. Deformation in the direction of north-south zones (such as Gazik and Afzalabad stations) is mostly done as transpersonal zones. In the distance between the left-lateral en-echelon faults with north-south trend (such as Cheshmezangi, Chakhoo, and Asakoohak), according to the type of their overlap, pressure zones (such as Kasrab and Torshab) have been formed. In the mentioned compressive zones due to the operation of the thrust faults, ophiolite units have been exposed in these regions. The existence of thrust faults in the end of strike-slip faults (such as South Birjand), which are due to the interaction of the main trends in the region, has caused ophiolite outcrops in the direction of northwest-southeast trends.

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