Initially, Great Britain was attached to continental Europe through a mountainous formation . Geologists already knew that. What was not clear was the way in which the rupture occurred that turned Great Britain into an island separated from Europe by the English Channel . Now, a study carried out by researchers from Imperial College London, published in the journal Nature Communications , reveals that a process of erosion and several massive floods gave the Strait or Pas de Calais its current shape in two different stages, which occurred 450,000 ago. and 160,000 years.
The union of the present British territory with continental Europe took place through the mountainous limestone rock formation that extends from the south-east of England to the north-west of France. 450,000 years ago – during the so-called Mindel glaciation – the ice stretched across the North Sea (from Scandinavia to southern England) and the entire English Channel was then dry land. According to Jenny Collier, a researcher at Imperial College London and co-author of the study, “at that time the area would look more like today’s Siberian tundra than the soft green landscape of our times . It was more of an icy world dotted with plunging waterfalls. on the cliffs of Dover. ” The presence of these mountains acted as a natural prey. Behind it was a glacial lake.
Following their analyzes, British geologists estimate that the lake’s first overflow was around 450,000 years ago . The flooding caused large floods to erode the limestone rock and cause the dam to collapse, releasing huge amounts of water into the canal. The researchers believe that the depressions formed on the seafloor were created by the water impacting the ground and eroding the rock. But it took a second massive flood, dated by these experts to 160,000 years from assemblages of marine mollusks found in coastal sediments, to fully open the Pas de Calais. A new system of valleys that make up the current Lobourg canal was shaped by this great flood.
According to the research, the overflow of other smaller lakes, which were in front of the ice sheets of the North Sea, could have driven this phase of erosion. In the opinion of Sanjeev Gupta, another of the study’s authors, “the breakdown of the land bridge between Dover and Calais was one of the most important events in British history, and it has shaped our current identity.” It was a geological Brexit.
Credit: Imperial College London / Chase Ston
