Writers : Khalilzadeh bajand,Bahareh;Khatib,Mohammad mehdi;Mohjal,Mohammad;Zarin koob,Mohammad hoseyn
Refference : 11th Symposium Of Geological Society Of Iran - Mashhad, Ferdowsi University
Publishing Year : 1386

Abstract :

Boushad shear zone in the south of Birjand ophiolite mélange have west- east trend that cause this ophiolite mélange divide to northern and southern part. This active shear zone has variable width and several km (4. 3km) displacements.
Asymmetric boudins in shear zones are as sufficient sense shear indicators. They can be divided into two groups, with slip on the inter-boudin surface that is either synthetic(S-slip) or antithetic (A-slip) with respect to bulk shear sense. Shearband boudins(formed by S-slip) have along, curved lenticular shap and large relative displacement and syntethic drag on an inter- boudin surface. Investigation of asymmetric boudins in trains parallel to the main foliation from the Boshad shear zone in south of Birjand ophiolite mélange indicate that these structures are shearband boudins have θ<60. Dilation across Sib is very rare and where present is very small, maximum 0.4. Aspect ratios of the boudin blocks are high about 15, and some cases to25-30.
Lateral displacement This Shearband boudins on Sib is very high about 5 that D/W diagram indicate it. form with synthetic sinistral slip on the inter-boudin surface, therefore indicate sinistral shear sense in this shear zone.

Subject List : Budin