Morphotectonics of Shaitanah Coastal Lagoon, Northwest of the Arabian Gulf

Abstract

Several lagoons (khors) are found in the northwestern Arabian Gulf, including Khor Al-Zubair, Shaitanah, Abdullah, and Subiya. Determining whether these lagoons formed through tectonic or sedimentary processes is essential for understanding their development and the region's geological stability. While most prior research has focused on hydrological and sedimentological aspects, comprehensive field studies of lagoon genesis remain limited. Ongoing debate centers on the relative roles of tectonic and sedimentary influences. This study aims to clarify the causes responsible for the creation of the Shaitanah lagoon, which links Khor Al-Zubair and Khor Abdullah to the Arabian Gulf.To address this gap, marine geophysical surveys were conducted using a Sub Bottom Profiler (SBP) and an Acoustic Doppler Current Profiler (ADCP), in addition to a geomorphic index of Transverse River Profiles (TRPs), which quantitatively assesses the topographic features of the seabed. The cross-sections indicate asymmetry in the seabed topography of the selected sections and discontinuity in the extent of the seabed layers. The cross sections also identify a steep slope and a sudden increase in depth to 15 m, representing the navigation channel of the khor, which shifts position across all cross sections. The results obtained from the geophysical surveys and TRPs analysis, in addition to the khor's channel meandering at an angle of more than 90 degrees and flowing from west to east, unlike all other khor in the region, indicate a direct link between tectonic influence and related fault systems, specifically the Jal Az-Zor fault, on the creation of the khor. This is consistent with previous studies on neotectonic effects across the entire northwestern Arabian Gulf region and on regional faults.