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Fishing Vessel In The Rough Waves, North Sea
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Geology
Shallow epicontinental seas like the current North Sea have since long existed on the European continental shelf. The rifting that formed the northern part of the Atlantic Ocean during the Jurassic and Cretaceous periods, from about 150 million years ago, caused tectonic uplift in the British Isles. Since then, a shallow sea has almost continuously existed between the highs of the Fennoscandian Shield and the British Isles. This precursor of the current North Sea has grown and shrunk with the rise and fall of the eustatic sea level during geologic time. Sometimes it was connected with other shallow seas, such as the sea above the Paris Basin to the south-west, the Paratethys Sea to the south-east, or the Tethys Ocean to the south.
During the Late Cretaceous, about 85 million years ago, all of modern mainland Europe except for Scandinavia was a scattering of islands. By the Early Oligocene, 34 to 28 million years ago, the emergence of Western and Central Europe had almost completely separated the North Sea from the Tethys Ocean, which gradually shrank to become the Mediterranean as Southern Europe and South West Asia became dry land. The North Sea was cut off from the English Channel by a narrow land bridge until that was breached by at least two catastrophic floods between 450,000 and 180,000 years ago. Since the start of the Quaternary period about 2.6 million years ago, the eustatic sea level has fallen during each glacial period and then risen again. Every time the ice sheet reached its greatest extent, the North Sea became almost completely dry. The present-day coastline formed after the Last Glacial Maximum when the sea began to flood the European continental shelf.
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