Seismic stratigraphy of the north-western Sea of Marmara shelf along the North Anatolian Fault system

The Ganos Fault, a part of the Northern strand of the North Anatolian Fault system, is an active- strike slip fault and divides the narrow NW shelf of the Sea of Marmara into two parts near the town of Gaziköy. This paper presents recently collected shallow high-resolution seismic data to discriminate the sedimentary successions, each characterized by distinctive stratigraphic patterns on both sides of the Ganos Fault. Two main units, namely U1 and U2, and three para-sequences (U1a, U1b and U1c) were identified, depending on their internal reflection patterns, accommodation depths as well as the presence of conformity and the unconformity surfaces. The thickness of Unit U1 reaches its maximum at the northern side of the Ganos Fault; it is much thinner to the south. The para-sequences of U1b and U1c have “progradation” and “aggradation to progradation” depositional characters, respectively. This probably implies fluvial deposition controlled by sea- level fluctuations. Unit U1b can only be observed at the northern side of the Ganos Fault, while Unit U1c at the southern side. Units U1a and U1b were deposited during the transgressive system tract, while Unit U1c was deposited during a sea-level fall and/or a lowstand phase marked by an erosional surface. The marine terraces in the study area are shallower than those along the northern shelf of the Sea of Marmara, possibly due to successive tectonic displacements along the Ganos Fault, which also controls the distribution and thickness of the parasequences identified in this study

Plio-Quaternary Sandy Deposits and Microbial Buildups at the Southern Marmara Shelf Near Shoreface Area, Turkey

Understanding the formation and evolution mechanism of the sandy deposits plays key role to define the hydrodynamics of the shelves and coasts. The barrier islands determined from high resolution chirp seismic reflection profiles, were started to deposit on the boundary (SB) that characterized by the lowstand stages of global sea level in the southern Marmara shelf near shoreface area. The unit haslost its activity at 55 ms, 60 ms depth in Erdek Bay, at 55 ms in Bandırma Bay, at 61 ms front of the Kocasu River. According to global sea level curves, this unit was evolved between 11000-11500 BP and10450-10150 BP. The geometrical situation and internal reflection character of these units indicate the balance between fluvial sediment transportation, marine intrusion and current systems in the study area. Belkis Isthmus that connects the Kapıdağ Peninsula to the mainland occurred synchronously with same process that formed the barrier islands. Bioherm structures were formed on the barrier islands and some of the bioherm’s uppermost surface is reached to 1 m below the sea floor. Bioherm structures are composing from organisms; formation and evolution depend on various stress factors. Barrier islands provide nutritional source to bioherms. Since these structures occur in a limited area, the development should be controlled by secondary factors. Biogenic gas determined from seismic sections closed to bioherm structures, probably plays the secondary role. Addition to this, during the forming and the growing of bioherms, Marmara Islands (Pasalimanı, Avşa, Marmara Islands) and Imralı Island were possibly control the currents and the flooding in the study area and provided convenient environment to these structures evolution

Plio-Quaternary Sandy Deposits and Microbial Buildups at the Southern Marmara Shelf Near Shoreface Area, Turkey

Understanding the formation and evolution mechanism of the sandy deposits plays key role to define the hydrodynamics of the shelves and coasts. The barrier islands determined from high resolution chirp seismic reflection profiles, were started to deposit on the boundary (SB) that characterized by the lowstand stages of global sea level in the southern Marmara shelf near shoreface area. The unit haslost its activity at 55 ms, 60 ms depth in Erdek Bay, at 55 ms in Bandırma Bay, at 61 ms front of the Kocasu River. According to global sea level curves, this unit was evolved between 11000-11500 BP and10450-10150 BP. The geometrical situation and internal reflection character of these units indicate the balance between fluvial sediment transportation, marine intrusion and current systems in the study area. Belkis Isthmus that connects the Kapıdağ Peninsula to the mainland occurred synchronously with same process that formed the barrier islands. Bioherm structures were formed on the barrier islands and some of the bioherm’s uppermost surface is reached to 1 m below the sea floor. Bioherm structures are composing from organisms; formation and evolution depend on various stress factors. Barrier islands provide nutritional source to bioherms. Since these structures occur in a limited area, the development should be controlled by secondary factors. Biogenic gas determined from seismic sections closed to bioherm structures, probably plays the secondary role. Addition to this, during the forming and the growing of bioherms, Marmara Islands (Pasalimanı, Avşa, Marmara Islands) and Imralı Island were possibly control the currents and the flooding in the study area and provided convenient environment to these structures evolution

Plio-Quaternary Sandy Deposits and Microbial Buildups at the Southern Marmara Shelf Near Shoreface Area, Turkey

Abstract Understanding the formation and evolution mechanism of the sandy deposits plays key role to define the hydrodynamics of the shelves and coasts. The barrier islands determined from high resolution chirp seismic reflection profiles, were started to deposit on the boundary (SB) that characterized by the lowstand stages of global sea level in the southern Marmara shelf near shoreface area. The unit haslost its activity at 55 ms, 60 ms depth in Erdek Bay, at 55 ms in Bandırma Bay, at 61 ms front of the Kocasu River. According to global sea level curves, this unit was evolved between 11000-11500 BP and10450-10150 BP. The geometrical situation and internal reflection character of these units indicate the balance between fluvial sediment transportation, marine intrusion and current systems in the study area. Belkis Isthmus that connects the Kapıdağ Peninsula to the mainland occurred synchronously with same process that formed the barrier islands. Bioherm structures were formed on the barrier islands and some of the bioherm's uppermost surface is reached to 1 m below the sea floor. Bioherm structures are composing from organisms; formation and evolution depend on various stress factors. Barrier islands provide nutritional source to bioherms. Since these structures occur in a limited area, the development should be controlled by secondary factors. Biogenic gas determined from seismic sections closed to bioherm structures, probably plays the secondary role. Addition to this, during the forming and the growing of bioherms, Marmara Islands (Pasalimanı, Avşa, Marmara Islands) and Imralı Island were possibly control the currents and the flooding in the study area and provided convenient environment to these structures evolution