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and the Alps
Alfred Wegener suggested that continents could derive on the surface of the earth, like pieces of a huge raft floating on the hot pastes which exist in the depths of the eart
Two hundred fifty millions years ago, all the emerged lands of the earth were welded in one single continent : the Pangaea.
Africa touches Europe, Spain occupies the Bay of Gascogne to the French Brittany, the Atlantic Ocean is closed, North America is attached to Europe.
Hundred and fifty millions years ago North America begins to separate of Europe by deriving westward. Spain parts from Brittany by turning on itself. A small a small Bay of Biscay gets dug and increases. Spain becomes an island alone in the Atlantic Ocean which is forming and continues to turn by coming down southward.
Everything begins by the rise of Italy towards northwest. Italy pushes away the old sedimentary deposits accumulated at the bottom of the alpine sea above the European continent which sinks under the weight.
As they emerge, all the summits are affected and the result of this erosion accumulates in them feet in the form of stiff stoneware : Molassa
Marine sediments accumulated in the old sea of TÚthys and which were pushed to the northwest on more than 140 kilometres, are called from now on Pre-Alps.
Their considerable weight provoked the sinking of the substratum and has create the Leman Lake.