GEOMORPHOLOGY OF THE HIGH FOLDED ZONE
The geomorphology of the Iraqi High Folded Zone (HFZ) is reviewed in the present article. The High Folded Zone is characterized mainly by mountainous topographic nature. The nature of the topography reflects the type of the exposed rocks and the structural effect. Generally, two main different topographical parts could be recognized, this is attributed to the presence of longitudinal and narrow anticlines and shallow synclines, locally faulted. Moreover, the surface of the HFZ area is dissected by complicated drainage patterns with variable density; they drain the area towards the main streams and rivers, and then toward the Tigris, Greater Zab, Lower Zab and Sirwan rivers. The chemical and mechanical weathering are active, the water is the main erosional agent being also an active process.
A generalized geomorphologic map of the HFZ is compiled, at scale of 1: 1000 000. The map elucidates the spatial distribution of the main geomorphologic units and the related morphologic features. The geomorphologic units are classified genetically into six classes, which include different landforms. The recognized genetic units are: Structural – Denudational, Denudational, Fluvial, Solution, and Man-made origins, and possible Glacial moraine. Each of these units includes different lithomorphologic landforms, which were developed due to weathering, erosion and depositional processes, in conjunction with tectonic, structural, lithological, and climatic factors.
The present study revealed that the geomorphologic evolution of the HFZ was greatly influenced by the last phase of intensive orogenic movement that took place during Late Miocene – Pliocene, and continued during the Quaternary Period with less intensity. During the Quaternary Period, the climate became a leading factor in controlling the majority of geomorphologic processes, particularly the fluvial. The Quaternary long-term climatic changes are deduced by well-developed river terrace stages along the main rivers and their tributaries, and some large streams and valleys, beside numerous alluvial fans and calcrete.