Structural geology of Qaleh Sorkh - Nowzad fault east of Birjand (Sarbisheh)

Nazari, Hamid

Structural geology of Qaleh Sorkh - Nowzad fault east of Birjand (Sarbisheh)

Document Type : Original Research Paper

Author

Hamid Nazari

Geological Survey of Iran, Tehran, Iran

Abstract

East Iranian structural Belt, one of pre-Cenomanian age. Stratigraphical and lithological evidence indicating the beginning of tensional morements between Iranian and Afghan microcontinents in Early Cretaceous. Thus, creating the sedimentary basins of East Iran and this in turn led to the appearance of the ophiolitie sequence in the area. The alleged ocean, created in this area, was closed during the Late Cretaceous and furthermore, the foreland basins were dominant features throughout the Cenozoic times.
Regarding the structural evolution of the area, varying hypotheses have been propounded. But, considering the structural characteristics of the area as. compared to the other parts of the Lut Block, the structural model of the Ghalehsorrh- Nowzad Fault is more feasible solution for the emplacement of the metamorphics as well as the ophiolitic sequences. The latter fault itself is one of the branches of the Neh Main Fault.
However, that Segment of Ghalehsorkh- Nawzad Fault in the east of the area of Sarbisheh, 1:100,000 Map is a strike-slip fault with a dextral disptacement in its first order class, whereas, occasionally sinistral in its secondary-third orders. The structural evolution of this fault occurred in the Riedel system with positive/negative flower structures in its compressional and tensional parts.
The stress mainly concentrating in the junction of different segments and in their tip points. The release of these stresses is likely the cause of the recent earthquakes.

Keywords

Qaleh Sorkh - Nowzad fault, Sarbisheh, Birjand

Subjects