The Study Petrofabric and Thermometry of South-Gharezagh S-type Syenogranite rocks (NW Iran)

The South-Gharezagh intrusive exposed in northwest of the Sorsat metamorphic complex, which is structurally a part of the Sanandaj-Sirjan zone. Intrusive of South-Gharezagh is located in the shear zone and are mylonitized. Morphologically, the crystallization of zircon in the intrusive and mylonitic mass of South-Gharezagh includes {110} prisms and {211} pyramids, which indicates their crystallization from S-type magmas. The crystallization temperature is calculated to be 698 to 770 ◦C, based on the morphology of zircon, in the massive and mylonitic parts of the South-Gharezagh massif, zircon saturation thermometry and geochemistry of the whole rock. In addition, the thermobarometric chemistry of biotite mineral has been calculated at a temperature of 677 ◦C and a pressure of 0.8 kbar. The petrofabric evidence shows that chemical and petrofabric changes have been gradually occurred along with the deformation progress in mylonites. As a result of petrofabric, the recrystallized quartz grains and the migration of the grain boundary in the recrystallization is clear, which indicates a change in the facies of the green schist metamorphism.