Last year Britain voted to leave the European Union. The hard-fought and divisive referendum will end many political ties with the continent. But, Britain was once physically joined to France via a vast land-bridge. SOUNDBITE (English) PROFESSOR SANJEEV GUPTA, PROFESSOR OF EARTH SCIENCES AT IMPERIAL COLLEGE LONDON, SAYING: "We think of Britain as an island separated from continental Europe. But 450,000 years ago Britain was actually connected to France by a land-bridge that stretched from southern England, from Kent, to north-west France... This rock ridge would have been made of chalk, so the famous White Cliffs of Dover would've actually stretched all the way across to France." Scientists say they have new evidence for how the opening of the Dover Strait in the English Channel occurred. Behind the chalk ridge, a huge proglacial lake overflowed in giant waterfalls. New geophysical data reveals huge holes and a valley system on the seafloor carved by thousands of years of cascading water. Eventually the chalk ridge failed, releasing huge volumes of water onto the valley floor below. SOUNDBITE (English) PROFESSOR SANJEEV GUPTA, PROFESSOR OF EARTH SCIENCES AT IMPERIAL COLLEGE LONDON, SAYING: "We've really proved this now; there must have been huge amounts of water plunging over. And what likely happened was that these holes were carved much like a dam, water plunging over a dam, and eventually there was so much water coming over this rock ridge that it probably caused breaching of this dam and initial opening of the strait." The researchers can't yet be sure of the exact timeline of events. For this they want to collect and analyse core samples of the sediments in the plunge pools. SOUNDBITE (English) PROFESSOR SANJEEV GUPTA, PROFESSOR OF EARTH SCIENCES AT IMPERIAL COLLEGE LONDON, SAYING: "So that would give us a timeline of when these dramatic events that have really shaped Britain's history actually happened." Doing this won't be easy - the Dover Strait is world's busiest shipping lane, and has huge tidal changes. But if successful, the team hopes to finally put a date on the Brexit that no one voted for.
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