An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by the Sea of Marmara, revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area, indicating that the sea level at ~ 8–9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at ~ 6.8–7 cal ka BP, drowning Lykos Stream and forming an inlet at its mouth. After ~ 3 cal ka BP, coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius; 4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th–9th centuries AD). The harbor was probably abandoned after the 11th century AD by filling up with Lykos Stream detritus and continued seaward migration of the coastline.
Abstract:The Devonian Period is represented in Turkey by almost complete non-metamorphic sections of more than 1000 meters, which exhibit varying lithofacial associations. They are parts of thick Paleozoic sedimentary successions in the Pontides, Taurides and Arabian Plate. The tectonic setting and the paleogeographical origin of these terranes is different. Therefore, the litho-and biostratigraphy and facies characteristics of these Devonian successions would enable a comparison and a paleogeographical assignment of these tectono-stratigraphic units. Devonian successions of the Arabian Plate and of the Taurides are represented by facies associations ranging from tidal flat to a deep shelf. Whereas, those of the Istanbul and Çamdag-Zonguldak areas in the Pontides by a deepening upward sequence from a shallow shelf into a basin and a stable shelf, respectively. The Devonian of the Arabian Plate and the Taurides can surely be assigned to Gondwana. A Peri-Gondwanan (Avalonian) setting is suggested for the paleogeographic position of the Devonian of the Pontides.
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.
In the eastern part of the Strandja Massif constituting the east end of the Rhodope Massif, the amphibolite facies basement rocks intruded by Permian metagranites are juxtaposed against the greenschist facies cover metasediments of Triassic-Middle Jurassic protolith age. The distinct metamorphic break between the basement and cover rocks requires a missing metamorphic section. The boundary between the two groups of rocks is a ductile to brittle extensional shear zone with kinematic indicators exhibiting a top to the E/NE shear sense. Footwall rocks are cut by weakly metamorphosed and foliated granite bodies which are clearly distinguished from the Permian metagranites by their degree of deformation, cross-cutting relations and syn-tectonic/kinematic character. Also, hangingwall rocks were intruded by unmetamorphosed and weakly foliated leucogranites. 40 Ar/ 39 Ar data indicate that the ductile deformation from 156.5 to 143.2 Ma (Middle Oxfordian-Earliest Berriasian) developed during the syntectonic plutonism in the footwall. Deformation, and gradual/slower cooling-exhumation survived until to 123 Ma (Barremian). The mylonitic and brittle deformation in the detachment zone developed during OxfordianEarliest Berriasian time (155.7-142.6 Ma) and Early Valanginian-Aptian time (136-118.7 Ma), respectively. Our new field mapping and first 40 Ar/ 39 Ar ages demonstrate the existence of an extensional core complex of Late Jurassic-Early Cretaceous age not previously described in the Rhodope/Strandja massifs.
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