Document Type: Original paper (Research paper)
North Golpaygan region is composed of deformed metamorphic rocks that are cut and covered by Mesozoic to Tertiary magmatic and sedimentary rocks. Different metamorphic rocks including schist, marble, slate, gneiss and amphibolite outcrop as a core complex structure in this area. The purpose of this work is to introduce deformation mechanisms and microstructures formed during different deformational stages in these metamorphic rocks. Thermometry of synmetamorphic deformation is also estimated based on quartz grain boundaries and calcite twins in quartz-feldspathic rocks, calcschists and marbles. The results show that the variety of microstructures and deformation mechanism, characteristics of low-grade to medium grade deformation, are formed during four stages of the regional deformation (D1, D2, D3 and D4). Based on mineral thermometry and geometry of the recrystallized quartz grains, temperature of the deformation is estimated between 511 to 618 ˚C during prograde stage of metamorphism and 300 ° C during retrograde stage and contact metamorphism.