TY - JOUR T1 - Late Pleistocene-Holocene evolution of the northern shelf of the Sea of Marmara JF - Marine Geology Y1 - 2009 A1 - Cagatay, M. N. A1 - Eris, K. A1 - Ryan, W. B. F. A1 - Sancar, U. A1 - Polonia, A. A1 - Akcer, S. A1 - Biltekin, D. A1 - Gasperini, L. A1 - Gorur, N. A1 - Lericolais, G. A1 - Bard, E. AB - Chirp sub-bottom profiling, multibeam bathymetric mapping and a combination of faunal and isotopic analysis of molluscs and foraminifera in sediment cores on the northern shelf of the Sea of Marmara (SoM) provide evidence of sea-level excursions, water exchanges between the adjacent Mediterranean and Black Seas, and oscillating salinity over the last 160 ka bp. During the marine isotope stages MIS-2, MIS-3, MIS-4 and MIS-6 the SoM disconnected from the Mediterranean Sea and evolved into a lake. During MIS-1, MIS-5 and MIS-7, the SoM reconnected and became salty once again. Sapropels formed shortly after each invasion of Mediterranean saltwater observed in our cores. Concurrent suboxic-dysoxic conditions prevailed over quite shallow substrates on the shelf. Ancient shorelines are pervasive at -85 m on the northern shelf and in the region of Prince Islands coincident with the elevation of the modern bedrock sill in the Canakkale (Dardanelles) Strait. At times when global (eustatic) sea level dropped below this sill, the surface of the SoM stabilized at its outlet and freshened. Thus this particular shoreline is interpreted as the edge of the most recent SoM lake that existed from about 75 ka bp to 12 ka bp. The freshening is observed in very light (-6 parts per thousand) values of delta O-18 measured on freshwater molluscs and the complete absence of foraminifera. Two brief lacustrine episodes during MIS-5 suggest that the level of the Canakkale outlet might have been as shallow as -50 m in the past, a likelihood supported by submerged terraces along its margins bounding the modern central channel and the presence of an euryhaline biofacies in Unit L4.1 corresponding to MIS-5b. delta O-18 profiles and carbon-14 dating show that salinification of the SoM and the blossoming of bioherms evolved rapidly after the latest connection with the Mediterranean at 12 ka bp. However, freshening proceeded more slowly once the connection was severed. (C) 2009 Elsevier B.V. All rights reserved. VL - 265 IS - 3-4 N1 - id: 1843; 500UN Times Cited:1 Cited References Count:80Y JO - Late Pleistocene-Holocene evolution of the northern shelf of the Sea of Marmara ER - TY - JOUR T1 - The North Anatolian fault in the Gulf of Izmit (Turkey): Rapid vertical motion in response to minor bends of a non-vertical continental transform JF - Journal of Geophysical Research Y1 - 2006 A1 - Cormier, M. H. A1 - Seeber, L. A1 - McHugh, C. M. G. A1 - Polonia, A. A1 - Cagatay, M. N. A1 - Emre, O. A1 - Gasperini, L. A1 - Gorur, N. A1 - Bortoluzzi, G. A1 - Bonatti, E. A1 - Ryan, W. B. F. A1 - Newman, K. R. VL - 111 N1 - id: 532 ER - TY - JOUR T1 - Submarine earthquake geology along the North Anatolia Fault in the Marmara Sea, Turkey: A model for transform basin sedimentation JF - Earth and Planetary Science Letters Y1 - 2006 A1 - McHugh, C. M. G. A1 - Seeber, L. A1 - Cormier, M. H. A1 - Dutton, J. A1 - Cagatay, N. A1 - Polonia, A. A1 - Ryan, W. B. F. A1 - Gorur, N. AB - The submerged portions of the North Anatolia Fault system beneath the Marmara Sea were studied with high-resolution multibeam bathymetry, subbottom profiling and sediment cores. The major objectives were to learn about the seismic and tectonic history of the fault from the stratigraphic record at a scale similar to paleoseismic studies on land and to develop tools for submarine earthquake geology that can be applied to fault-controlled basins in general. We focused on Holocene sediment in several Marmara Sea basins of different sizes. The approach was to test whether: (1) the depocenters of the larger basins contain a record of all historic Ms > 7 earthquakes within the Marmara Sea region; (2) the small transform basins record earthquakes that rupture through them; (3) vertical and strike-slip Holocene deformation can be quantified; and (4) the effects of an earthquake generally includes both primary structural features due to rupture of the sea floor, such as strata offset, scarps and tilting, as well as secondary effects due to shaking, such as mass-wasting and gravitational flows. We found evidence of earthquakes that we correlate with historic events in 181 AD, 740 AD, 1063 AD, 1343 AD, 1509 AD, 1766 AD, 1894 AD and 1912 AD. The geologic evidence is primarily from those basins adjacent to the rupture as inferred from historic data. This suggests that coseismic deformation of the sea floor along the rupture is a critical factor in the sedimentary record. We propose a qualitative sedimentation model that relates this coseismic deformation to mass-wasting of the slope, scour of the basin floor, seiche motions and homogenite deposition. Frequent earthquake activity sheds sediments from the flanks, contributes to the much thicker sediment on the basin floor and decreases the likelihood of sediment failures in response to normal marine gravity-driven processes. The surveying techniques and approaches used have therefore the potential of documenting earthquake ruptures of fault segments and to extend the earthquake record far before the known history, thus improving hazard evaluations and the fundamental understanding of earthquake process. (c) 2006 Elsevier B.V. All rights reserved. VL - 248 IS - 3-4 N1 - 085kgTimes Cited:55Cited References Count:98 JO - Submarine earthquake geology along the North Anatolia Fault in the Marmara Sea, Turkey: A model for transform basin sedimentation ER - TY - JOUR T1 - Sea-level changes and depositional environments in the Izmit Gulf, eastern Marmara Sea, during the late glacial-Holocene period JF - Marine Geology Y1 - 2003 A1 - Cagatay, M. N. A1 - Gorur, N. A1 - Polonia, A. A1 - Demirbag, E. A1 - Sakinc, M. A1 - Cormier, M. H. A1 - Capotondi, L. A1 - McHugh, C. A1 - Emre, O. A1 - Eris, K. AB - Offshore and onshore stratigraphic studies, together with high-resolution shallow seismic reflection profiling and multibeam bathymetric mapping, were carried out in the western and central part of the Izmit Gulf. These studies indicate that the Izmit Gulf was a lacustrine environment as part of the Marmara 'Lake' during the late glaciation and early deglaciation until similar to12 kyr BP, when the Marmara Basin was inundated by the Mediterranean waters. Correlation of C-14-dated onshore and offshore stratigraphic units in the Western Izmit Gulf indicates that generally coarse late glacial sediments overlie a marked erosional surface formed during the low water level of the Marmara 'Lake'. These coarse sediments are succeeded by 10.4-7 kyr BP old transgressive, and by late Holocene post-transgression mud units. The bathymetry and sub-bottom Chirp profiles clearly show that the paleoshoreline of the Gulf was located at -85 m, having been controlled by the bedrock sill depth of the Canakkale Strait. Another paleoshoreline observed at -65 m on the northern margin of the Western Izmit and Karamursel basins was probably formed during the Younger Dryas sea-level stillstand. The shelf areas during this time were colonized by bioherms, which were subsequently drowned and disappeared after a further rise of the sea level. The presence of a -65 in marine paleoshoreline in the Karamursel Basin indicates that the sill restricting this basin to the west was much deeper than its present -55 in level and was located further south. The Golcuk Basin, restricted by a -38 in sill to its west, was probably not flooded by marine waters until similar to9 kyr BP. (C) 2003 Published by Elsevier B.V. VL - 202 IS - 3-4 N1 - 749gpTimes Cited:52Cited References Count:30 JO - Sea-level changes and depositional environments in the Izmit Gulf, eastern Marmara Sea, during the late glacial-Holocene period ER - TY - JOUR T1 - An abrupt drowning of the Black Sea shelf JF - Marine Geology Y1 - 1997 A1 - Ryan, W. B. F. A1 - Pitman, W. C. A1 - Major, C. O. A1 - Shimkus, K. A1 - Moskalenko, V. A1 - Jones, G. A. A1 - Dimitrov, P. A1 - Gorur, N. A1 - Sakinc, M. A1 - Yuce, H. AB - During latest Quaternary glaciation, the Black Sea became a giant freshwater lake. The surface of this lake drew down to levels more than 100 m below its outlet. When the Mediterranean rose to the Bosporus sill at 7,150 yr BP1, saltwater poured through this spillway to refill the lake and submerge, catastrophically, more than 100,000 km(2) of its exposed continental shelf. The permanent drowning of a vast terrestrial landscape may possibly have accelerated the dispersal of early neolithic foragers and farmers into the interior of Europe at that time. (C) 1997 Elsevier Science B.V. VL - 138 IS - 1-2 N1 - Xj245Times Cited:283Cited References Count:35 JO - An abrupt drowning of the Black Sea shelf ER -