65TH Geological Congress of Turkey, Ankara, Turkey, 1 - 04 April 2012, pp.174-175
The main purpose of this study is to investigate the Late Quaternary water exchanges between the Mediterranean and Black Sea’s and related postglacial prevailing erosional processes and their influences on seafloor. This work was partly supported by the TÜİAK projects ÇYDAG- 104Y024 and YDABÇG-102Y113 and comprises large number of seismic and batyhmetric data evaluation. During the years between 1979-2007 in the Çnakkale Strait (“Dardanelles”) and its Aegean Sea and Marmara Sea approaches seismic reflection profiles were obtained with high resolution and single channel seismic systems and data-processed with subsequent seismic facies analysis and interpretation according to well-known methods. At least 4 seismic units were identified on the profiles. The uppermost Unit-1 is characterized by prallel reflections of flat-lying configurations and covered by present sea-floor. Unit-1 represents relatively low-energy conditions and is 1 m thick in channel depressions but 10 m thick in shelf areas and reaches deposits up to 30 m off the river mouths. These locally changing sediment thicknesses show the importance of Holocene erosional, transportation and depositional processes on the Çnakkale Strait’s floor. Unit-2 is separated by an unconformity and terminate with onlap onto older below units. The upper boundary of Unit-2 display an erosional character and indicate at the Aegean and Marmara Sea’s exits oblique and prograding delta deposits whereas incised channel-fill sequences are are common within the channel. Unit-2 displays locally changing seismic reflection configurations and thus can be divided into 3 subunits, 2a, 2b and 2c. Unit-3 is observed mainly on the Marmara and Aegean shelves of the strait terminate with continuous and onlapping parallel reflectors onto the erosional surface of Unit-4. The thickness of Unit-3 reaches upto 200 m on both shelf breaks. The upper surface of Unit-4 is erosional and in Karaburun Promontory and Marmara Island areas it unconformably overlies pre-Miocene basement whereby its outcrops at the shores is interpreted as the submarine extension of the upper Miocene units. In the Aegean Sea, between the Göçada Island and Biga Peninsula there exists a paleo-valley where surface of Unit-4 deepens from the south to north and infilled by deposits of Unit-3. It is most likely that Unit-1 and 2 deposits belong to last glacial and interglacial periods and Units-3 and 4 were deposited before last Glacial Maxima. It is suggested that sea-level changes, changing channel morphology and current regime together with different fluvial drainage systems all control sediment transportation and depositional conditions in the Çanakkale Strait.
Keywords: Çanakkale Strait, Quaternary, sea-level change, seismic stratigraphy, sediment