Document Type : Original Research Paper
Authors
1 1Department of Geology, University of Birjand, Birjand; Geological Survey of Iran,Mashhad, Iran
2 Department of Geology, University of Birjand, Birjand, Iran,
3 Department of Geology, University of Birjand, Birjand, Iran
4 Research Institute, Geological Survay of Iran, Tehran,Iran
Abstract
The Boushad shear zone (BSZ) is situated in the south of Birjand with at least 45 km length, about 9.2 Km width and strike N90E. The parts of the ophiolite mélange shear zone south of Birjand have changed by this shear zone. The earliest deformation, a polyphasesynmetamorphic deformation which occurred entirely in ductile conditions, D1 and D2 deformation phases are related to this deformation. The D3 deformation affected the area after a period of sedimentation and erosion, Tension gash veins are formed simultaneously. The Strike-slip faults, thrust faults and fault related folds were classified as structures related to the D4 tectonic event, the most recent phase of conflict in the region N055 ±10E is formed. Degree of convergence of the shear zone is R = 0.3, that indicating the formation of a dextral Transpression (Slightly oblique-convergent).
Keywords
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