Some science behind the scenes
Doggerland
Doggerland was named after the Dogger Bank, which in turn was named after the 17th century Dutch fishing boats called doggers.
Doggerland was an area now beneath the southern North Sea that connected Great Britain to continental Europe during and after the last glacial period. It was flooded by rising sea levels around 6,500–6,200 BC. Geological surveys have suggested that it stretched from Britain's east coast to the Netherlands and the western coasts of Germany and the peninsula of Jutland. It was probably a rich habitat with human habitation in the Mesolithic period, although rising sea levels gradually reduced it to low-lying islands before its final submergence.
The archaeological potential of the area was first identified in the early 20th century, but interest intensified in 1931 when a fishing trawler operating east of the Wash dragged up a barbed antler point that was subsequently dated to a time when the area was tundra. Vessels have dragged up remains of mammoth, lion and other animals, as well as a few prehistoric tools and weapons.
During the most recent glaciation of the Last Glacial Maximum, which ended around 18,000 years ago, the North Sea and much of the British Isles were covered with glacial ice and the sea level was about 120 m (390 ft) lower.
Subsequently, the climate became warmer and during the Late Glacial Maximum around 12,000 BC, Britain, as well as much of the North Sea and English Channel, was an expanse of low-lying tundra.
Evidence, including the contours of the present seabed, indicates that after the first main Ice Age, the watershed between the North Sea and English Channel extended east from East Anglia then south-east to the Hook of Holland, rather than across the Strait of Dover. The Seine, Thames, Meuse, Scheldt and Rhine rivers joined and flowed west along the English Channel as a wide slow river before eventually reaching the Atlantic Ocean. At about 10,000 BC the north-facing coastal area of Doggerland had a coastline of lagoons, saltmarshes, mudflats and beaches as well as inland streams, rivers, marshes and lakes. It may have been the richest hunting, fowling and fishing ground in Europe in the Mesolithic period [in northwest Europe about 10,000 to 5000 BCE].
As ice melted at the end of the last glacial period of the current ice age, sea levels rose and the land began to tilt in an isostatic adjustment as the huge weight of ice lessened. Doggerland eventually became submerged, cutting off what was previously the British peninsula from the European mainland by around 6500 BC. The Dogger Bank, an upland area of Doggerland, remained an island until at least 5000 BC. Key stages are now believed to have included the gradual evolution of a large tidal bay between eastern England and Dogger Bank by 9000 BC and a rapid sea-level rise thereafter, leading to Dogger Bank becoming an island and Great Britain becoming physically disconnected from the continent.
A recent hypothesis postulates that much of the remaining coastal land was flooded by a megatsunami around 6200 BC, caused by a submarine landslide off the coast of Norway known as the Storegga Slide. This suggests:
"that the Storegga Slide tsunami would have had a catastrophic impact on the contemporary coastal Mesolithic population.... Britain finally became separated from the continent and in cultural terms, the Mesolithic there goes its own way."
A study published in 2014 suggested that the only remaining parts of Doggerland at the time of the Storegga Slide were low-lying islands, but supported the view that the area had been abandoned at about the same time as the tsunamis.
Another view speculates that the Storegga tsunami devastated Doggerland but then ebbed back into the sea, and that later Lake Agassiz (in North America) burst releasing so much fresh water that sea levels over about two years rose to flood much of Doggerland and make Britain an island.
The three Storegga Slides are considered to be amongst the largest known landslides. They occurred under water, at the edge of Norway's continental shelf in the Norwegian Sea, approximately 6225–6170 BCE. The collapse involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km3 (840 cu mi) of debris, which caused a very large tsunami in the North Atlantic Ocean. This would be the equivalent volume to an area the size of Iceland covered to a depth of 34 m (112 ft).
Based on carbon dating of plant material recovered from sediment deposited by the tsunami, the latest incident occurred around approximately 6225–6170 BCE. In Scotland, traces of the subsequent tsunami have been recorded, with deposited sediment being discovered in Montrose Basin, the Firth of Forth, up to 80 km (50 mi) inland and 4 m (13 ft) above current normal tide levels.
Observations
For iPad/iPhone users: tap letter twice to get list of items.