Akademik Veri Yönetim Sistemi
Doklady Earth Sciences, cilt.522, sa.2, 2025 (SCI-Expanded)
Abstract: Sand structures are natural and sometimes unnatural structures that are prominent features both in coastal areas and on the continental shelf. Naturally occurring formations such as sand dunes, sandbars, and barrier islands are shaped by the continuous influence of wind and water, playing a crucial role in coastal dynamics and ecological stability. Additionally, human interventions, including dredging, artificial reefs, and sand fences, further contribute to the modification and preservation of these landscapes. Their location and formation depend on the presence of sand, the ability of tidal forces and other current systems to move sand. Subaqueous sand structures close to coasts protect beaches; the interference and refraction of waves along banks play a decisive role in shaping coasts. Therefore, understanding the formation and development phases of these structures and their interactions with shorelines has many important benefits. The formation, development and activity of sand structures in southwestern Erdek Bay (Marmara Sea), a semi-enclosed basin, were studied with seismic reflection and multibeam bathymetry data. Sediment deposition in the study area is under the control of the material carried by two important rivers and current systems. The Gönen River is the main source of the material that forms these structures, and the longshore currents carry the material to locations where sandy structures developed. The NWN-SES orientation of the sand structures are shaped where the main synclonic current system bends and erosional processes increase as the current loses its effect towards the depths. It has been revealed that this effect creates this current change because the local area receives fresh water from the Biga River. This riverine input blocks like a wall the current system and cause the formation of sand structures. The effects of these two rivers in the study area have ensured the existence and development of sand structures there. These structures started to form before the last lowstand sea level, and some of them are still active. It has been determined that active accumulation continues, especially near the shore toward the Biga River, and these structures merge where they are under the influence of NNW currents.