Abstract

Korek Anticline as a part of the Arabian plate is located within high folded zone of the Zagros Fold-Thrust Belt (ZFTB) in Kurdistan Region of Iraq. The present study is an attempt to look at the structural and geomorphological phenomena of the Korek Anticline. The geometrical analysis of Korek Anticline indicated that this fold is asymmetrical double plunging, open to gentle fold, non-cylindrically curvi-planar fold. The Korek Anticline becomes sharper with the depth, but broader and more open upward, this is one of the most recognized characteristic features of the parallel fold (Class 1B). The presence of a numerous reverse faults and strike-slip faults are recognized which affect the architecture of Korek Anticline.

The most important geomorphological landscape and landforms in the studied area are endogenic (i.e. uplifting, folding, faulting, jointing) and exogenic (weathering, erosion, sedimentation, mass wasting, karstification) processes. Geomorphologically, the study region divided into four main units, which are recognized as units of structural origin, units of denudational origin, units of fluvial origin and units of solution origin. And each unit contains many sub-units.

The morphotectonic analysis in the study area can be done by using some geomorphic criterion, such as drainage network, fold front sinuosity and topographic profile along fold crest. According to the result of this geomorphological criterion the Korek Anticline propagated in both northwest- ward and southeast- ward from the central part.

The kink style folding of Korek Anticline accommodate with high angle reverse faults in the northeastern limb and presence of overturned 

strata at the southwestern limb of the Korek Anticline in the Cretaceous succession supports our assumption that the Korek Anticline has a Fault-propagation fold mechanism.

Detailed balanced and retro-deformable cross sections in the studied area indicate  that the shortening percentage range between 7.83% to 20.31%, and the average of shortening percentage at all cross sections for Cretaceous (Qamchuqa Formation), Jurassic (Sehkaniyan formation), Triassic (KurraChina formation) and Late Paleozoic (ChiaZairi formation) are: 15.07%, 13.87%, 12.21% and 12.46% respectively. The estimation of the depth to detachment is about (10.04 km, 6.69 km, 6.3 km and 3.77 km) at the cross section (A-A¯, B-B¯, C-C¯ and D-D¯) respectively, below the regional horizon of Qamchuqa Formation, which is coincident with the Ora Shale Formation.

Morpho-structural model for this structure was constructed two main stages and five sub-stages were responsible in forming Korek structure. The first main stage is belonging to structural construction, which consist of three sub-stages, while the main second stage is belonging to geomorphological destruction, which consist also two sub-stages. This two construct and destruct give final shape of the Korek Anticline. 

 posted:18-1-2017