Strain analysis in the Sanandaj–Sirjan HP-LT Metamorphic Belt, SW Iran: Insights from small-scale faults and associated drag folds. (May 2015)

• Record Type: Journal Article
• Authors: Sarkarinejad, Khalil; Keshavarz, Saeede; Faghih, Ali
• Is Part Of: Journal of Asian earth sciences. Volume 105(2015)
• Page Start: 47
• Page End: 54
• Publication Date: 2015-05
• Subjects: Drag fold -- Finite strain -- Kinematics of deformation -- Zagros -- Iran; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jafrearsci.2015.02.006
• Languages: English
• ISSNs: 1367-9120

Abstract

Highlights: In the study area, drag folds and asymmetric folds all display a dextral sense of shear. The mean kinematic vorticity number was estimated using the drag fold. The estimated mean kinematic vorticity number is W k = 0.79. Abstract: This study is aimed at quantifying the kinematics of deformation using a population of drag fold structures associated with small-scale faults in deformed quartzites from Seh-Ghalatoun area within the HP-LT Sanandaj–Sirjan Metamorphic Belt, SW Iran. A total 30 small-scale faults in the quartzite layers were examined to determine the deformation characteristics. Obtained data revealed α 0 (initial fault angle) and ω (angle between flow apophyses) are equal to 83° and 32°, respectively. These data yield mean kinematic vorticity number ( W m ) equal to 0.79 and mean finite strain ( R s ) of 2.32. These results confirm the relative contribution of ∼43% pure shear and ∼57% simple shear components, respectively. The strain partitioning inferred from this quantitative analysis is consistent with a sub-simple or general shear deformation pattern associated with a transpressional flow regime in the study area as a part of the Zagros Orogen. This type of deformation resulted from oblique convergence between the Afro-Arabian and Central-Iranian plates.