Determination of shortening ratio based on geometry of Thrust sheets Argin shear zone (south of Birjand

Category Tectonic & Seismotectonic
Group GSI.IR
Location 21th symposium on geosciences
Holding Date 24 May 2008

      Argin compressional-sinstral shear zone in north of Bagheran mountain range, is one of the main phenomena that has been important in evolution of northern part of Sistan suture zone. The most common structural elements in this shear zone are thrust sheets that have created with convergent of oceanic lithosphere segments and flysch type deposits. Main strain axis attitude in this zone is:
   Z: N50, 12, Y: N217, 65, X: N145, 9
   And the attitude of main strain planes is:
   XY: N322, 70SW
   YZ: N53, 74NW
   XZ: N3, 15E
   Value of a angle and strain ratio is calculated for every thrust sheets and main shear zone. Shortening value for Argin compersional sinestral shear zone is calculated %27. Dip direction for most of thrust sheet are to north-northeast and the lithospheric segments vengeance are south-southwest. These processes caused asymmetric dip slopes in northern and southern parts of Bagheran mountain range.
   Shortening processes on Argin shear zone are increased dip slope in northern parts of Bagheran mountain range. So progressive structural uplifting in this zone is main factor for slope movements in this area.