Influence of the Tectonic Activity on the Terraces of the Greater Zab River, NE Iraq, Zagros Fold-Thrust Belt

Abstract

The study area lies in the Lower Folded Zone of the Outer Platform of Iraq, which belongs to the Arabian Plate. The Outer Platform is a part of the Zagros Fold-Thrust Belt, which is in the Zagros Foreland Basin. Due to the collision of the Arabian and Eurasian plates, tens of folds were developed among the anticlines that occur in the study area. The course of the Greater Zab River in the study area crosses several anticlines before merging with the Tigris River. Different river terrace levels were recognized locally as three levels along the course of the river. It is clear from the achieved data that the rates of an incision during the Early, Middle and Late Pleistocene are: 5.036 mm/ 100 years, 8.979 mm/ 100 years, and 18.117 mm/ 100 years, respectively. The maximum rate of upward movements (3.485 mm/ 100 year) was recorded at 700 m from Bekhme gorge, where the first exposures of the Fatha and Injana formations exist. The maximum rate of downwards movement (13.769 mm / 100 year) was recognized at the southeastern part of Barda Rash anticline. The rate of the upwards movement decreases towards the southeast, and the minimum rate of downwards (7.314 mm / 100 year) was recorded in Sarta oil well 1 location, near the Greater Zab River. The rates of the upwards and downwards movements are not regular. This is attributed to the existence of anticlines and synclines, which means Neotectonic activities.