MARINE GEOPHYSICAL RESEARCH, cilt.36, sa.1, ss.1-34, 2015 (SCI-Expanded)
This study is based on the geological interpretation
of 250 km2 of multibeam bathymetric data coupled
with 300 km of seismic profiles recorded on the northern
shelf of the Marmara Sea offshore Bu¨yu¨kc¸ekmece and
Ku¨c¸u¨kc¸ekmece Lagoons. The sea bottom morphology has
a highly chaotic structure at the exit of the Bu¨yu¨kc¸ekmece
and Ku¨c¸u¨kc¸ekmece lagoons. This chaotic surface structure
is controlled by a basin-ridge system lying in the NE–SW
direction at the exit of the Bu¨yu¨kc¸ekmece Lagoon and by a
relatively deep entrance observed at the exit of the
Ku¨c¸u¨kc¸ekmece Lagoon. In addition, the linear submarine
slope parallel to the shoreline between the Istanbul Strait
and the Ku¨c¸u¨kc¸ekmece Lagoon is an important morphological
structure of this area. The Istanbul Strait’s canyon
on the northern shelf of the Marmara Sea and the elevated
submarine plain west of this canyon are other important
morphological structures observed at the sea bottom. The
geologic interpretation of seismic profiles has allowed us to
distinguish two seismo-stratigraphic units. The lower one is
separated from the overlying units by a seismic sequence
having a seismic facies from chaotic to parallel and the top
represented by a high amplitude seismic reflector. Since
these units get close to the sea bottom rising landwards,
they are inferred to be the seaward continuation of the
Oligocene–Upper Miocene units widely exposed on land.
The upper unit, overlying the acoustic basement, whose
parallel internal reflections onlap and downlap on the top of
the acoustic basement, is interpreted as a Quaternary basin
fill. Two groups of faults have been identified on seismic
profiles and identified based on their characteristics in the
study area. The first group consists of dip-slip faults
trending NNE–SSW. These faults border the western slope
of the Bosporus and the NNE–SSW trending basins offshore
of the Bu¨yu¨kc¸ekmece Lagoon. The second group of
faults consists of NW–SE oriented strike-slip faults. These
faults have created the linearities in the same direction at
the sea bottom. As the result of comparison of these NW–
SE-faults to the North Anatolian Fault Zone (NAFZ), this
group of faults is likely to have a relation with the NAFZ.
Therefore, it is considered that the mentioned faults may be
reactivate