Britain became separated from mainland Europe after a catastrophic flood some time before 200,000 years ago, a sonar study of the English Channel confirms. The images reveal deep scars on the Channel bed that must have been cut by a sudden, massive discharge of water. Scientists tell the journal Nature that the torrent probably came from a giant lake in what is now the North Sea. Some event - perhaps an earthquake - caused the lake's rim to breach at the Dover Strait, they believe.The idea of a great flood stems from scientists' understanding of northern Europe's ice age past. It is believed that hundreds of thousands of years ago, when ice sheets had pushed down from Scotland and Scandinavia, there existed a narrow isthmus linking Britain to continental Europe. This gently upfolding chalk ridge was perhaps some 30m higher than the current sea level in the English Channel.
Palaeo-researchers think it bounded a large lake to the northeast that was filled by glacial meltwaters fed by ancient versions of the rivers Thames and Rhine. Then - and they are not sure of the precise date - something happened to break the isthmus known as the Weald-Artois ridge. (BBC News)
