450,000 years ago, the first Brexit...
TEN months after the EU referendum, it may feel as though Brexit is taking an exceedingly long time.
But our separation from Europe actually started almost half a million years ago. Now geologists have found the best evidence yet of how we became an island.
During an ice age almost 450,000 years ago, sea levels were low and what we call the English Channel was dry land.
But the team, from Imperial College London, say that when the ice age ended, a giant lake formed behind the chalk wall connecting Dover and Calais, which acted like a huge dam keeping the Channel dry.
As the ice melted, the water in the lake rose and burst over the barrier, cascading over in around six huge waterfalls and weakening the chalk.
Later, after perhaps hundreds of thousands of years, a ‘mega-flood’ smashed over the weakened barrier and cut across the Dover Strait, severing us from Europe and forming the iconic white cliffs of Dover.
Co- author Professor Sanjeev Gupta, from Imperial’s department of earth science and engineering, said this was ‘one of the most important events in British history, helping to shape our island nation’s identity even today’.
He added: ‘Without this dramatic breaching Britain would still be a part of Europe. This is Brexit 1.0.’ The geologists looked at huge underwater pits and trenches on the Channel’s seabed.
Giant valleys called the Fosses Dangeard were discovered in the 1960s and, after finding more of them, the geologists are convinced they are ‘plunge pools’ created by the waterfalls.
The plunge pools are in a straight line, suggesting the water cascaded off one single ridge – the land bridge between Europe and Britain.
Professor Gupta added that, because sea levels in the Dover Strait are quite shallow, Britain could one day rejoin continental Europe if there is another ice age.