A 2.5×10 km body of NE-trending mylonitic granite is exposed north of Aliabad-e-Damag, 35 km south of Hamadan. Mylonite and the surrounding schists have concordant fabrics parallel to the dominant foliation in the region. Structural and fabric analysis suggests deformation in a dextral strike-slip shear zone. The strong deformation and associated low grade metamorphism were coeval with plastic intrusion and continued to the end of crystallization. The granite has a retrograde thermal effect on the surrounding metamorphic rocks. Sigmoidal geo-metry of the large Hamadan pluton and the position of the dextral shear zone at the southeastern part of this system indicate the significance of dextral transpression tectonic in this region of the Sanandaj-Sirjan zone and rotation of the shear fractures in emplacement of the Aliabade-e-Damag pluton and subsequent intrusion of the Hamadan batholith