Islands of the Tectonic Origin in the Shatt Al-Arab River, Southern Iraq

Abstract

Several factors control the formation of river islands, such as tectonic factors, sedimentation, erosion, and human activities. This research is concerned with islands in the Shatt Al-Arab channel, which are likely to be traced back to tectonic factors in their formation. The islands of the Shatt Al-Arab River are distributed along its axis starting from the islands of Sindbad and Muhammadiyah, 15 km to the north of the city center of Basra, to the islands of Shatit, Al-Dawasir and Minauhi, 70 km south of the city center of Basrah. This study area is part of the Mesopotamia Plain, southern Iraq. The fieldwork period extended from the beginning of September 2012 to June 2013, which included making subsurface sections (longitudinal and transverse) of the bottom of the Shatt Al-Arab channel using the Sub-bottom profile Strata box device, imaging the topography of the river bottom in a side scan sonar, collecting the bottom sediments by a grab sampler. The volumetric analysis method uses the Master Sizer device based on the Folk classification to calculate the volumetric gradient of sediments. The study showed that the tectonic factor has a prominent role in the growth island Maino and as a result of the presence of sub-surface structures for the structure of the Siba, which appeared to affect the subsurface layers of the river bed near the island as it appeared in the survey sections of the Strata box device. There are some islands that more than one factor emerged as a reason for their formation and development, as in the islands of Muhammadiyah and Umm al-Rasas, where tectonic and sedimentary factors interfered in their formation and development due to the influence of sub-surface structures as well as the influence of nearby rivers such as the Karma and Karun Rivers.