Geological History
The Black Sea, like the Mediterranean, is a remnant of the Tethys Sea that closed when Africa and India collided with Eurasia during the Paleogene Period, 65 million to 25 million years ago. Before the closing of the seaway, the upwarping of the Taurus and Zagros Mountains split the Tethys Sea into two waterways: the Vardar Sea (Paratethys) on the north, and the Hathay-Euphrates Straits on the south. The northern branch of the waterway has become the Black Sea, while the southern branch has become the Tigris-Euphrates Valley and the Persian Gulf (Por, 1989).
