Late quaternary sedimentation in the strait of bosporus: high-resolution seismic profiling

Alavi, Seyed Naeim
Okyar, Mahmut
Köse, Timur
Uniboom profiling supported by borehole data in the southern part of the Bosporus revealed that close to its banks Holocene sediments are underlain by the faulted slopes of a valley cut in many places into the Palaeozoic bedrock. Away from the banks the sediments thicken and their boundary with the underlying Pleistocene deposits is defined by an erosional surface at about the 80 ms TWT. This surface marks the initiation of marine currents in the valley as its deeper parts began to be submerged in the late Pleistocene to early Holocene (marine spillway phase). The upward-coarsening Holocene sequence records the subsequent evolution of the present two-way marine strait. The sequence is divided into three seismostratigraphic units. The lowest one constitutes an onlapping fill deposited under salt-wedge estuarine conditions when sediment input and runoff discharge were high and sealevel was still rising but the flow of Mediterranean waters into the Black Sea was not continuous. It fills low areas and is well developed under a sill close to the southern entrance of the Strait. As sealevel rose closer to its present level and the rate of terrigenous input decreased in the middle Holocene, this unit began to be eroded and reworked by strong bottom currents. The second unit records the transitional stage between the estuarine phase and the present two-layered current system. Its seismic facies and sedimentary features indicate deposition under high-energy conditions and shifting loci of accumulation. The third (surficial) unit is a thin depositional lag rich in shell fragments blanketing the other two units. It records deposition under fully marine conditions and flow of powerful bottom currents during the last few millenia.


ERGIN, M; OKYAR, M; TIMUR, K (Elsevier BV, 1992-02-29)
High-resolution shallow-seismic reflection (Uniboom) profiles obtained in inner and mid-shelf areas of eastern Mersin Bay (Turkey, northeastern Mediterranean) show that the sedimentary column comprises two major and distinct lithological sequences (C and B) separated by a reflector (R) which is interpreted as the pre-Holocene surface. The upper sedimentary sequence (C) is thought to represent roughly the Holocene and is characterized by parallel/divergent to sigmoidal reflection patterns above (Unit 1) and ...
Volcano stratigraphy and petrogenesis of the Nemrut stratovolcano (East Anatolian High Plateau): The most recent post-collisional volcanism in Turkey
Ozdemir, Y; Karaoglu, O; Tolluoglu, AO; Güleç, Nilgün Türkan (Elsevier BV, 2006-02-28)
The Nemrut stratovolcano, with its well defined summit caldera, is the most recent volcanic eruption center (1441 A.D.) in the East Anatolian High Plateau, one of the best examples of an active colllision zone. Widespread volcanism has been active in this region for the last similar to 10 Ma, producing large volumes of lavas and pyroelastics covering a broad belt, across the Bitlis Suture Zone, from the Anatolian plate in the north to the Arabian plate in the south.
EDIGER, V; OKYAR, M; ERGIN, M (Elsevier BV, 1993-11-01)
High-resolution shallow seismic reflection (Uniboom) and echosounding profiles obtained on the shelf and upper slope areas of Anamur Bay (Turkey, northeastern Mediterranean) were studied together with previous data on the onshore geology of the area to investigate the origin and related seismic stratigraphy of the submarine Anamur Canyon. It was found that the main axial trend of the submarine Anamur Canyon is aligned with the offshore projection of the N-S orientated, onshore Anamur thrust fault of Late Cr...
Sub-ophiolite metamorphic rocks from NW Anatolia, Turkey
Onen, AP; Hall, R (Wiley, 2000-09-01)
The metamorphic rocks from near Kutahya in north-west Anatolia record different stages in the history of closure of the Neo-Tethyan Izmir-Ankara-Erzincan ocean. Sub-ophiolite metamorphic rocks within the Tavsanli zone are a tectonically composite sequence of quartz-mica schists, amphibole schists, amphibolites and garnet amphibolites. They show increasing metamorphic grade towards the base of the ophiolite. A first metamorphic event, typical of sub-ophiolite metamorphic sole rocks, was characterized by high...
Recent sedimentation on the shelf and upper slope in the Bay of Anamur, southern coast of Turkey
Alavi, Seyed Naeim; Ediger, Volkan S.; Ergin, Mustafa (Elsevier BV, 1989-9)
Sedimentological studies, supported by Uniboom profiles and sonographs, of surface sediments from a part of the narrow southern shelf of Anatolia, indented by the head of a submarine canyon and partly covered by meadows of macrophytobenthos, revealed abrupt lateral and vertical variations in the Holocene sedimentary facies. These variations have essentially been controlled by the migration of depocentres, (palaeo-) topography of the shelf and an overall decrease in the rate of fluviatile sediment supply in ...
Citation Formats
S. N. Alavi, M. Okyar, and T. Köse, “Late quaternary sedimentation in the strait of bosporus: high-resolution seismic profiling,” Marine Geology, pp. 185–205, 1989, Accessed: 00, 2020. [Online]. Available: