Britain’s split from the European Union may have formally begun last week but scientists have found evidence of a Brexit that happened long, long ago.
Researchers have just published a study in the journal Nature Communications about how a thin land bridge that once connected ancient Britain to Europe was destroyed.
The land bridge in question was a roughly 32-kilometre wide rock formation that ran from Dover to Calais.
The rock was made of chalk so when the land was ripped away it formed the landmark that is known as the White Cliffs of Dover.
The researchers believe that a huge glacial lake, which lies to the north of the former land bridge, may have been responsible for the ancient Brexit.
The separation occurred in two stages with the first stage occurring about 450,000 years ago. At that time the Earth was in an ice age, with vast glaciers covering the North Sea and parts of Scandinavia.
At the edge of the massive ice sheet was a lake and it is hypothesised that it overflowed, sending vast amounts of water crashing into the thin strip of land.
The second stage is thought to have taken place around 150,000 years ago when seismic activity caused a second flood which totally destroyed the already damaged land bridge.
Engineers first became aware of the lake decades ago when they were surveying the seabed for the digging of the Channel Tunnel. They found that the seabed had large underwater holes, most likely caused by the lake overspill.
Lead author of the study Dr. Sanjeev Gupta of Imperial College London told BBC News:
They [the holes] occur in a line – a whole series of them stretching between Dover and Calais. And they are huge, 100m-deep carved into the bedrock and hundreds of metres to several kilometres in diameter. So we interpret these as giant plunge pools. We think there was basically lake water plunging over this rock ridge in the Dover Strait through a whole series of waterfalls, which then eroded and carved out these depressions.
It wasn’t Dr Gupta’s first time investigating the area. In 2007, he and Dr Jenny Collier, also from the Imperial College London, studied the underwater topography of the English Channel.
This initial study supported the idea that flooding destroyed the land bridge which once connected Britain and Europe.
Dr Gupta and Dr Collier want to learn more about this geological Brexit, including information about the precise timing of the catastrophic flooding events. They have now teamed up with Belgian and French seismologists to continue their exploration of the bedrock between Dover and Calais.
However, there will be considerable challenges involved. The channel is world’s busiest shipping route and studying the ocean floor will require crossing two shipping lanes.
“Scuse me cap’n, I’d like to study the sea floor to find out more about the ancient geological Brexit.”, probably wouldn’t go down well with most cargo ships.
Many people are unhappy with Britain leaving the EU but this was the Brexit that no one voted for.
Geologists say that Britain and Europe will one day be reunited whether we like it or not – but we’ll have to wait for the next ice age.
The last one occurred 12,000 years ago and they tend to happen about every 100,000 years.
It’s further proof that we account for just a fraction of a second on the cosmic clock.