Weald-Artois anticline
The Weald-Artois anticline is a mountain ridge made of chalk rock that runs from the so-called Weald region in the south of England from Kent to Artois in eastern France and touches the areas of Dover and Calais . 225,000 years ago this area was not yet separated by the English Channel .
The word anticline means a geological saddle that is created by folding and opening rock layers through its bulge. Here, the term is limited in the narrower sense to those bulges in which the original arrangement of the layer sequence is preserved.
The Weald-Artois anticline bulged during the Alpidic Orogeny , when the current shape of the mountains in Europe developed about 100 to 5 million years ago . In geological terms, this orogenesis formed between the Cretaceous period and the strongest uplift phase in the late Miocene . The ice ages of the Pleistocene significantly shaped the appearance of today's mountains.
In the north-east of the ridge is an area that was formed by an ice age lake and lies below the sea level of the North Sea . To the south-west, low-lying areas joined that used to connect England, Scotland and Wales with the continent and are now covered by the English Channel.
The first glacier run that separated England from continental Europe happened around 425,000 years ago, with a water ingress of up to a million cubic meters per second carving the depression of what is now the English Channel out of the ridge.
The second run of the glacier, which was probably even more powerful than the first, occurred around 225,000 years ago and finally separated Great Britain from the mainland.