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Post-Tethyan Basin Evolution |
atay2
1 
stanbul Teknik Üniversitesi, Maden Fakültesi, Jeoloji Mühendislii Bölümü, Ayazaa, TR-80626, stanbul, Turkey cagatay{at}itu.edu.tr
2 stanbul Üniversitesi, Deniz Bilimleri ve 
letmecilii Enstitüsü, Vefa, TR-34470, stanbul, Turkey
3 Institute of Geography, Russian Academy of Sciences, 10917 Moscow, Russia
The Neogene marginal succession of the Eastern Paratethys (EP) crops out along the southern Black Sea coast and in the Marmara region of Turkey, and provides important clues to the tectono-sedimentary and palaeoceanographic conditions.
In the Tarkhanian stage, the southern margin of the EP basin was largely a carbonate platform covered by warm, marine waters. From the end of the Tarkhanian to the Early Chokrakian there was an overall emergence throughout the basin, which is indicated by an influx of siliciclastic sediments. The fossil assemblage indicates that normal marine conditions persisted during most of this period, except for a salinity reduction towards the end due to an eustatic isolation of the basin, which in turn led to anoxic bottom water conditions. The Late Chokrakian isolation became even more severe during the Karaganian as indicated by the endemic fossil assemblage indicating brackish-marine conditions. Carbonate platform conditions prevailed in the northern Pontides during this time. In the Early Konkian, the basin was reconnected briefly with the world ocean by a transgression from the Indo-Pacific Ocean. In the Late Konkian there was a return to brackish-marine conditions.
Lower Sarmatian sediments are absent in the southern margin of the EP, but elsewhere in the basin this stage is characterized by a widespread marine transgression. In the Middle-Late Sarmatian, the EP basin was partially isolated with freshening and anoxic bottom-water conditions. During this time there was a brief marine transgression from the Mediterranean into the Marmara region, but it did not reach the Paratethyan basin. The Pontian is characterized by an extensive transgression from the EP that inundated the Marmara and northeastern Aegean regions. The connection with the Marmara Basin was cut off during the Kimmerian and re-established during the Late Akchagylian, when the EP basin was inundated by the Mediterranean waters via the Sea of Marmara as a result of increased North Anatolian Fault activity and a short-term global sea level rise.
