Analysis of geometric and kinematic parameters of strain on the open gash veins within the ‎Boushad shear zone (Birjand Ophiolitic Mélange, eastern Iran)

Naimi-ghassabian, N; Khatib, M. M; Ghasemi Rozveh, T; Nazari, H; Heyhat, M.R

doi:10.22071/gsj.2016.40679

Analysis of geometric and kinematic parameters of strain on the open gash veins within the ‎Boushad shear zone (Birjand Ophiolitic Mélange, eastern Iran)

Document Type : Original Research Paper

Authors

N Naimi-ghassabian ¹

M. M Khatib ²

T Ghasemi rozveh ³

H Nazari ⁴

M.R Heyhat ³

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

10.22071/gsj.2016.40679

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

Boushad shear zone

Birjand ophiolitic mélange

strain parameters

Transpressional shear zone

Sistan suture