Investigation of deformation pattern using finite strain and kinematic vorticity analyses, Cheshmeh Sefid deformed area, Sanandaj-Sirjan metamorphic belt.


1 Faculty of Earth Sciences, Shahid Chamran University, Ahvaz, Iran

2 Department of earth Sciences,Shiraz University, iran


      Deformed conglomerates and microconglomerates of Mesozoic in the Sanandaj-Sirjan Metamorphic Belt are the most suitable kinematic markers for the strain studies. The R /  technique for two dimensional strain analysis show that the finite strain of X/Z plane in comparison to X/Y and Y/Z aspect ratios, is highest (Rs=5.4). The calculation of harmonic mean from axial ratio of extracted pebbles and transfer these data into Flinn diagram determine K= 0.6 to 0.9. Kinematic vorticity analysis of deformed porphyroclasts show that kinematic vorticity number (Wk) varies from 0.43 to 0.63. These amounts of Wk show that both simple and pure shear components act in this area. With application of the kinematic vorticity results the percent of pure and simple shear was determined so that (30% <simple shear < 42%) and (58 %< pure shear <70%). These results show the nature of deformation with pure shear dominated due to convergence movement between Afro-Arabian continental plane and Iranian microcontinent. Shortening values in the study area measured parallel to the XZ principal plane of the finite strain ellipsoid are calculated using strain and vorticity results. The estimated values of shortening generally range from 42% to 55% in the study area.


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