Kinematic vorticity analysis of the Deh Zaman mylonitic granite based on deformed feldspar grains

Deh-Zaman mylonitic granite is located northwest of the Lut Block (Kashmar-Kerman zone) in the northeastern part of Kuh-e-Sarhangi shear zone. In this granitic body (~557-561 Ma), mylonitic foliation with S62˚E/80NE attitude is very well developed. The mean pitch of stretching lineation is ~40 ˚ toward the southeast. The main purpose of this study is to quantify the vorticity number based on the strain of feldspar crystals. The microstructural evidence of the feldspar crystals indicates that the sense of shear is left-lateral strike-slip in the region. The presence of moderately euheadral porphyroclasts of feldspar with observed dynamic recrystallization of grain boundary migration type, indicates ~450°C deformation temperature that shows a low to medium grade mylonite. The vorticity number of this mylonite granite is estimated to be 0.8 based on the feldspar crystal strain. This indicates the predominance of simple shear component (60%) over pure shear (40%) and the development of mylonitic structure under transpression conditions.