The Genesis and Morphometry of the main Transversal Gorges in the Pera Magrun and Sara Anticlines, Iraqi Kurdistan Region, NE of the Arabian Plate

摘要

Abstract The Pera Magrun and Sara are two anticlines in the Sulaimaniyah Governorate in the Iraqi Kurdistan Region. Both of them are NW–SE trending double plunging anticlines with a very steep southwestern limb; locally overturned. The anticlinal ridges are mainly developed within the rocks of the Qamchuqa Formation and partly within the rocks of the Kometan Formation. The ridges are densely dissected by steep valleys forming giant flatiron morphology. The southwestern limbs of both anticlines are dissected by streams of canyon type. At the Pera Magrun Anticline, the Zewe and Tabin gorges were formed while the Jasana and Qamchuqa gorges were formed in the Sara Anticline. The genesis and maturity of those four transversal gorges are discussed and their presence at particular locations and developments are investigated. This study was carried out by a field investigation and the interpretation of satellite images, which were used to calculate geomorphic indices, and stream parameters and some sinuosity indices to indicate the morphometry and relative tectonic activity of the studied streams, besides geological and topographical maps. It is found that the origin of the Zewe, Jasana, and Qamchuqa gorges are related to strike-slip faults, whereas the Tabin gorge is a water gap that developed due to the lateral growth of the Pera Magrun anticline, and is more mature than the other three gorges. Moreover, different morphometric characteristics of the four gorges are given.