Black Sea deluge hypothesis
The Black Sea deluge is a hypothesized catastrophic rise in the level of the Black Sea circa 5600 BC from waters from the Mediterranean Sea breaching a sill in the Bosphorus strait. The hypothesis was headlined when The New York Times published it in December 1996. It was later published in an academic journal in April 1997. While it is agreed that the sequence of events described by the hypothesis occurred, there is debate over the suddenness, dating and magnitude of the events. Over geological eras, water has flowed in and out of the Black Sea basin. This hypothesis concerns the occurrence of the last inflow and the primary point of controversy is whether the event was gradual or catastrophic.
In 1997, William Ryan and Walter Pitman published evidence that a massive flooding of the Black Sea occurred about 5600 BC through the Bosphorus. Before that date, glacial meltwater had turned the Black and Caspian Seas into vast freshwater lakes draining into the Aegean Sea. As glaciers retreated, some of the rivers emptying into the Black Sea declined in volume and changed course to drain into the North Sea. The levels of the lakes dropped through evaporation, while changes in worldwide hydrology caused overall sea level to rise. The rising Mediterranean finally spilled over a rocky sill at the Bosphorus. The event flooded 155,000 km2 (60,000 sq mi) of land and significantly expanded the Black Sea shoreline to the north and west. According to the researchers, "40 km3 (10 cu mi) of water poured through each day, two hundred times the flow of the Niagara Falls. The Bosphorus flume roared and surged at full spate for at least three hundred days."
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