Black Sea - Mediterranean Connection During The Holocene

Mediterranean Connection During The Holocene

The Black Sea is connected to the World Ocean by a chain of two shallow straits, the Dardanelles and the Bosphorus. The Dardanelles is 55 m (180.45 ft) deep and the Bosphorus is as shallow as 36 m (118.11 ft). By comparison, at the height of the last Ice age, sea levels were more than 100 m (328.08 ft) lower than they are now. There's also evidence that water levels in the Black Sea, too, were considerably lower at some point during the post-glacial period. Thus, for example, archaeologists found fresh-water snail shells and man-made structures in roughly 328 feet (100 m) of water off the Black Sea coast of modern Turkey. Therefore it is agreed that the Black Sea has been a landlocked freshwater lake (at least in upper layers) during the last glaciation and for some time after.

In the aftermath of the Ice Age, water levels in the Black Sea and the Aegean Sea rose independently until they were high enough to exchange water. The exact timeline of this development is still subject to debate. One possibility is that the Black Sea filled first, with excess fresh water flowing over the Bosphorus sill and eventually into the Mediterranean Sea. There are also catastrophic scenarios, such as the "Black Sea deluge theory" put forward by William Ryan and Walter Pitman.