Kinematics of the Tanbour Metamorphic Complex (SE Iran): Implications for Cenozoic Metamorphism and Deformation in the Northeastern Margin of the Afro-Arabian Plate

• Published in: Geotectonics 2023-04, Vol.57 (2), p.213-229
• Main Authors: Mansouri, S. M., Keshavarz, S., Shahpasandzadeh, M., Faghih, A.
• Format: Article
• Language: English
• Subjects: Amphibolites; Cenozoic; Deformation; Earth and Environmental Science; Earth Sciences; Kinematics; Metamorphism; Microstructure; Plates; Shear; Shear deformation; Strain analysis; Structural Geology; Vorticity
• ISSN: 0016-8521; 1556-1976
• DOI: 10.1134/S001685212302005X

New petrofabric studies joined with kinematic vorticity and finite strain analyses allowed to recognize the deformation characteristics of the mid-crustal rocks exposed in the the Tanbour Metamorphic Complex (Iran). Different scale sense of shear criteria in the Tanbour Metamorphic Complex reveal an unequivocal top-to-the-SE sense of shear within this part of the Sanandaj–Sirjan metamorphic belt. Well-developed quartz c -axis within selected mylonitic samples was utilized to estimate bulk kinematic vorticity. W k values ranging from 0.65 to 0.86, thus indicating non-coaxial shear deformation with contemporaneous pure and simple shear components. Integration of microstructure- and petrofabric-based geothermometers indicates temperature of mylonitization ranges between ~450‒650°C corresponding from upper greenschist to amphibolites facies metamorphism. Data obtained support interpretations suggesting occurrence of transpressive deformation during ongoing continental collision of the Afro‒Arabian and Iranian plates.