Akademik Veri Yönetim Sistemi
Marine Geophysical Research, cilt.46, sa.2, 2025 (SCI-Expanded, Scopus)
The depositional and erosional systems along the northern shelf of the Sea of Marmara is investigated by focusing on the interplay between riverine inputs, sea-level fluctuations and tectonic activity. The seismic data is represented by two major depositional units (U1 and U6) together with additional subunits (U2, U3, U4, U5) identified in the eastern sector of the study area, each reflects influence of riverine sedimentation and sea-level changes. Unit U2 exhibits an ascending deposition pattern, indicative of transgression, while U3 shows a descending pattern, reflecting high stand and low stand systems. Unit U4 has progressive wavy semi-parallel and mounded internal reflections with some younger deposits above and it can be delineated in a shape of channel structure deposited in a limited area. The intense landscape erosion along the shelf during the Younger Dryas period (∼ 12,000 years bp) is evidenced by truncation surfaces of unit U4, correlating with sea levels of 60–70 m. Unit U5, is a distinct deposition for the canyon, highlights the complexity of sediment accumulation processes. The depositional history at the southern exit of the İstanbul Strait’s reveals a local system influenced by sediment supply exceeding accommodation space, with unit U2's aggradation and progradation patterns suggesting a transgressive origin. River flow velocity is recognized as a critical factor in delta formation, with high velocities facilitating sediment transport and low velocities encouraging deposition. This study challenges the single-source deposition model by proposing a multi-source origin influenced by both the Strait itself and riverine inputs to the east. Tectonic activity, especially compressional tectonics, is prominent in the western section, where anticlinorium structures and active faults are observed. The absence of faulting activity in recent deposits suggests a variable tectonic regime, as supported by the high-resolution seismic data in this study. This research underscores the complex interplay of fluvial, marine, and tectonic processes shaping the depositional systems at the southern exit of İstanbul Strait, providing insights into sea-level changes and sediment dynamics in the Sea of Marmara.