Open AccessSeismic stratigraphy of the north-western Sea of Marmara shelf along the North Anatolian Fault system
Author(s) -
Denizhan Vardar,
Hakan Alp,
Sinan Demirel,
Hande Aykurt Vardar,
Bedri Alpar
Publication year - 2021
Publication title -
annals of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 60
eISSN - 2037-416X
pISSN - 1593-5213
DOI - 10.4401/ag-8591
Subject(s) - geology , progradation , north anatolian fault , unconformity , fault (geology) , seismology , paleontology , sedimentary rock , tectonics , sedimentary depositional environment , fluvial , growth fault , strike slip tectonics , isopach map , onlap , geomorphology , structural basin , facies
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.