LATE QUATERNARY CHRONOLOGY OF THE SOUTHERN BLACK-SEA BASIN

During New Euxinian time when sea level dropped below the sill connecting the Black and Marmara seas, the Black Sea became isolated and freshwater sediments were deposited. Now it is a semieuxinic basin with the oxic/anoxic boundary at 100-150 m. The seasonal changes in sedimentation are preserved in the form of laminated sequences. The counting of varves in southeastern Black Sea cores show the chronology of the O2/H2S interface. The age of the Holocene sapropel along the eastern margin ranges from 4000 to 1000 yr BP in deep water and 2500-1000 yr BP in shallower water. Sapropel formation started at 3650 yr BP at a water depth of 2200 m.