Pressure-temperature analysis of deformation based on the quartz petrofabric characteristics (case study of Samen deformed granite, Sanandaj-Sirjan metamorphic belt)


Faculty of Earth Sciences, Shahid Chamran University of Ahvaz



Understanding the different deformation processes during which quartz mineral undergoes preferred orientation can be useful for geologists to realize the conditions of paleo-strain. Temperature and geometry of deformation are two main factors that control the nature of quartz lattice preferred orientation. Granite and gneiss rocks are important tectonic features in orogenic belts that form in both compression and tension tectonic regimes. Samen deformed granite in the Sanandaj-Sirjan metamorphic belt is an important granite bodies in the northwest of Iran. In this research the quartz c-axis fabric have been studied in the mylonitic parts of Samen deformed granite. The results indicate that the c-axis pattern of the quartz mineral has developed related to the non-coaxial deformation flow with a right-lateral sense of shear. Petrofabric analysis showed that the quartz mineral has been deformed due to the development of sub-grain rotation and grain boundary migration recrystallization regimes in the temperature range of 393 ± 50 to 531 ± 50 °C and the pressure about 3.2 to 5.3 kbar.


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