Britain might presently be going through a breakup from Europe politically , but geographically it separate from it almost half a million years earlier . fit in to a paper inNature Communications , this was because of water sweeping out of a glacial lake in what is now the North Sea . Unlike former theories of the operation , however , the study arrogate it took at least two major result to complete the separation .
During the ice age , seas come as vast quantities of water became locked up in polar meth canvas . This exposed the demesne beneath the English Channel , along with many other area that are now shallow sea , so that it was possible to take the air from Calais to Dover .
History Quran often incriminate that all it took for Britain to part from mainland Europe was rising sea levels , but the Sojourner Truth was more complex . During an interglacial time period 450,000 class ago , a rooftree of land run from southeast England to France stand up above the waves provide a walk . It was only when this ridge collapsed that detachment happen .
This collapse was clear a significant event – think how unlike European account might have been without it . Consequently , geologists have puzzled over how and why it occurred . First authorProfessor Sanjeev Guptaof Imperial College , London , recollect he has answered those questions .
Like predecessors , Gupta claims that what is now the southern North Sea filled with water from melt glaciers as the ice sheets withdraw .
“ While it is widely hold that initial curtain raising of the Strait was a import of spillover of a proglacial lake that exist in the southerly North Sea catchment basin … direct grounds for this spillover physical process has up to now been miss , ” the paper notes . By mapping the sea story beneath the distribution channel in unprecedented detail , Gupta has revealed the presence of a drawstring of sediment - filled plunge pool at the base of chalk escarpments . He fence these divulge the presence of huge falls that once discharged many time the volume of Niagara Falls .
These crepuscle outwear the stone aside as water rushed from the arctic lake to the North Atlantic . finally the ridgeline give way , isolating Britain . Subsequent ice ages saw the seas retreat and Britain connected to the mainland again several clip . With the ridge ’s higher footing gone , however , each clock time sea level rear , there was nothing to maintain Britain ’s geographical connection to the continent .
However , a feature film of the Channel ’s seafloor , known as the Lobourg Channel , thwartwise - cuts these pools . Gupta concluded this could only have occurred if the kitty spring and fill up with sediment first , before a subsequent catastrophic photoflood cut up the Lobourg Channel , determining that each subsequent thawing would isolate Britain again .
The profundity of the ocean floor across the Dover Straight , showing the deep channel carved in a ruinous flood . The chalk ridge once connect France to Britain . Imperial College London / Professor Sanjeev Gupta and Dr Jenny Collier
