Reprocessing and Interpretation of the High Resolution Seismic Data from Northern Marmara Continental Shelf, NW Turkey (original) (raw)
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Annals of Geophysics, 2021
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 Gazikoy. 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 o...
Earth Planets and Space, 2007
Seismic data on the NE Marmara Sea Shelf indicate that a NNE-SSW-oriented buried basin and ridge system exist on the sub-marine extension of the Paleozoic Rocks delimited by the northern segment of the North Anatolian Fault (NS-NAF), while seismic and multi-beam bathymetric data imply that four NW-SE-oriented strike-slip faults also exist on the shelf area. Seismic data indicate that NW-SE-oriented strike-slip faults are the youngest structures that dissect the basin-ridge system. One of the NW-SE-oriented faults (F1) is aligned with a rupture of the North Anatolian Fault (NAF) cutting the northern slope of the Çınarcek Basin. This observation indicates that these faults have similar characteristics with the NS-NAF along the Marmara Sea. Therefore, they may have a secondary relation to the NAF since the principle deformation zone of the NAF follows the Marmara Trough in that region. The seismic energy recorded on these secondary faults is much less than that on the NAF in the Marmara Sea. These faults may, however, produce a large earthquake in the long term.
Marine Geology, 2002
The Gemlik Bay is developed as a pull-apart basin during the late Pliocene-early Pleistocene mainly controlled by west-trending dextral strike-slip faults along the middle strand of the North Anatolian Fault zone, with the NW-trending Thrace-Eskişehir Fault playing secondary role. The North Anatolian Fault reached the eastern Marmara Sea ∼3.5 Ma ago, where its middle strand intersected the Thrace-Eskişehir Fault. GPS slip vectors measured on the Armutlu and Mudanya blocks show a displacement of 7–8 km during the last 3.5 Ma. The middle strand of the North Anatolian Fault zone has lower tectonic activity than the northern strand. Because uplift of the southeast Marmara Sea region has been continuous since the late Pliocene, the presence of fluviatile, lacustrine and deltaic environments in the Gemlik pull-apart basin over the same period supports a lower lever of tectonic activity. The transgressive Marmara Formation was deposited on top of these fluvio-lacustrine deposits following the Mediterranean inundation at ∼600 ka via the Strait of Çanakkale. The Gemlik basin was affected both by two major sea-level falls at 160–132 and 24–11 ka, and minor short-lived sea-level variations, as a result of becoming a lacustrine setting five times since ∼600 ka. During these lowstands, stacked delta successions were deposited around the lake and on the transgressed shelves of the Marmara Sea.