THE great flood thought to have prompted the tale of Noah鈥檚 ark was preceded by an even bigger flood thousands of years earlier, according to analysis of data from the Black Sea collected by scientists from the Soviet Union.
During the last ice age, which peaked around 20,000 years ago, the Black Sea was a landlocked freshwater sea that lay more than 100 metres below its current level. As the Mediterranean rose after the ice age, it flooded into the Black Sea. Geologists Bill Ryan and Walt Pitman of the Lamont Doherty Earth Observatory in New York have previously dated this flood to 7600 years ago. They also linked it to biblical stories of catastrophic floods (快猫短视频, 4 October 1997, p 24).
Now analysis of sediment and seismic data from the Black Sea shows that water from the Caspian Sea flooded into the area about 14,000 years ago. It also indicates that the Mediterranean overflow took place more than 1000 years earlier than Ryan and Pitman suggest, and was less dramatic.
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Valentina Yanko-Hombach at the Avalon Institute of Applied Science in Winnipeg, Manitoba, and Andrey Tchepalyga from the Institute of Geography in Moscow will tell next week鈥檚 meeting of the International Union for Quaternary Research in Reno, Nevada, that the data shows the level of the Black Sea began to rise about 14,000 years ago.
What鈥檚 more, Yanko-Hombach says, this was caused by water from the Caspian Sea, which was overflowing with waters from melting glaciers. The inflow raised the Black Sea by 80 metres in around 1000 years, she says, driving out the Late Palaeolithic inhabitants of the basin.
After the Caspian overflow stopped, the level of the Black Sea fell. Meltwater continued to raise the level of the Mediterranean, and Ryan and Pitman suggest that seawater flooding would have filled the basin in a few years. But Yanko-Hombach says that the first Mediterranean species appeared in the Black Sea about 8900 years ago, marking the first overflow from the south. She believes that this event raised the Black Sea only about 40 metres and took many more years to do so than Ryan and Pitman suggested.
