THE QUATERNARY HISTORY OF THE PONTO-CASPIAN BASINS

During the Tertiary, the Paratethys Sea covered the region north of the Alps from Central Europe to the Aral Sea in Western Asia. From the Pliocene epoch onward (5 mya), the Paratethys became progressively shallower and subdivided into several inland seas that were at times completely separated from each other. Many of these would disappear before the Pleistocene, but today, only the Ponto-Caspian basins remain.

The Ponto-Caspian is defined here as a chain of intercontinental basins that encompasses the Caspian, Black, Azov seas, the Kerch Strait, the Manych Valley, and their coasts. During the Quaternary, the Black Sea was repeatedly connected with the Caspian Sea via the Manych outlet as well as with Mediterranean Sea through the Bosphorus or Izmit Bay-Sapanca Lake-Sakarya Valley. This predetermined environmental conditions and hydrologic regimes of the Ponto-Caspian basins and imposed specific impacts on diverse biological populations, including humans inhabiting the coastal domains.

Due to its geographical location and semi-isolation from the open ocean, this region acts as a paleoenvironmental amplifier and a sensitive recorder of climatic events, in particular glacial-interglacial cycles on the Eastern European Plain and mountains as well as transgressive-regressive sea-level variations of the World Ocean. It can be considered as a stratotype region for the Pleistocene stratigraphy of Northern Eurasia.

This presentation outlines the most recent ideas on the Quaternary geological history of the Ponto-Caspian basins based on multidisciplinary studies of the geological and paleontological records supplemented by absolute dating. It will detail the sequence of basin connection and isolation, sea levels, salinity, and correlations with major climatic events and Marine Isotopic Stages. A comparison with the data obtained by stratotypes and δ¹⁸O signatures in stacked speleothems from Sofular Cave in northern Turkey will also demonstrate a number of water intrusions from the Mediterranean and Caspian seas into the Black Sea. Particular attention will be paid to the last 30 ka in order to discuss proposed flooding of the Black Sea by Mediterranean and Caspian water in the early Holocene and terminal Pleistocene, respectively. This paper is a contribution to IGCP 610 and outlines the main goals of the project.