Geomorphic Assessment of Lateral Growth of Active Folds in the Fars Arc, Zagros Fold-Thrust Belt, Iran (Case Study: Herang and Kuh-e-Namaki Anticlines)

The existence of lateral propagation of folds above blind reverse faults is an important hypothesis and is generally accepted. In this research, the growth pattern of active folds (e.g., Herang and Kuh-e-Namaki anticlines) in the Fars Arc located in the Zagros Fold-Thrust Belt is investigated tectonic geomorphology point of view. The main goal of this research is to use geomorphometric indices such as drainage pattern, drainage density, drainage basin asymmetry factor and stream length-gradient to determine direction of lateral fold growth with a special focus on the process of linkage of several different fold segments. Geomorphological studies show that some folds in the Zagros did not develop a single embryonic fold but by lateral linkage of several different fold segments. The linkage type (linear or en-echelon linkage) of different fold segments depends on the alignment of the initial embryonic folds. Investigation of geomorphometric indices in the study area shows that the Herang anticline resulted lateral growth and en-echelon linkage of three embryonic folds while the Kuh-e-Namaki anticline resulted linear growth of a single embryonic fold and cannot be considered as a result of linkage of several different segments.