Dogger Bank is a name I remember from when I was a teenager. It was regularly mentioned in a weather forecast especially for the fishers, broadcasted just before the morning news. Yes, on the radio, we had no TV when I was a teenager, which was back in the 1950's.
Dogger Bank is a large sandbank in a shallow area of the North Sea. It extends over approximately 17,600 km
2. The water depth ranges from 15–36 m, about 20 m shallower than the surrounding sea. It is a productive fishing bank. The location of the Dogger Bank is marked with a red line in the following satellite image.
10,000 years ago, which means just after the latest glacial, or in other words the Early Holocene, the Dogger Bank was a range of hills in a land area covering a large part of what is now the southern North Sea. You could walk from Denmark or Germany to England – well you would have to cross a few rivers, of course, as there were no bridges – and archaeologists have documented that the land was populated. The archaeologists have named it “Doggerland”. I don't know how appropriate the name Doggerland is considering that “dogge” is an old Dutch word for fishing boat (better related to the fishing bank!). The following map shows the hypothetical extent of Doggerland about 10,000 years ago.
As sea levels rose after the end of the last glacial, and the level of the land sank due to isostatic adjustment after the Scandinavian ice cap had melted, Doggerland became submerged beneath the North Sea, cutting off what was previously the British peninsula from the European mainland around 8500 years ago. The Dogger Bank, which had been an upland area of Doggerland, is believed to have remained as an island until at least 7000 years ago.
I would like to highlight two events with special impacts on Doggerland.
First the drainage of the large North American glacial lake, Lake Agassiz. The catastrophic meltwater release from Lake Agassiz may have caused an abrupt 0.25–0.5m sea-level jump around 8300 years ago, and triggered the so-called ‘8200 calBP’ cold event around the Atlantic. This would have inundated a large part of Doggerland and furthermore it may have become unusually cold and windy on the remaining coasts of Doggerland.
Secondly the Storegga Slide Tsunami about 200 years later or around 8000 years ago, which would have had a catastrophic impact on the ontemporary coastal Mesolithic population. Following the Storegga Slide tsunami, it appears, Britain finally became separated from the continent and, in cultural terms, the Mesolithic there goes its own way.
The submarine Storegga landslide off the Norwegian coast is now usually described as three subsequent slides. The second of these generated a tsunami that apparently involved some 2400–3200 km
3 of material that spread across the North Atlantic sea floor, altogether covering an area of around 95 000 km
2. Traces of this tsunami have been identified in many regions in the North Atlantic, including Scotland, England and Denmark, but it also seems to have propagated as far as to the east coast of Greenland. The slide occurred at a time when the sea level in the southern North Sea stood about 17 m higher than the present level.
As we are talking about a coastal area Doggerland was probably relatively densely populated for that time – I am talking about near 1 inhabitant per km3. Maybe some 700 to 3000 individuals were affected. This does not necessarily imply that all were killed immediately, although given the likely rapidity and scale of the event, a significant number of people would almost certainly have been caught and drowned by the rapidly rising waters, while many others would have been displaced. The consequences would not have been limited to the wave’s immediate impact, as productive coastal areas could have been devastated, shellfish beds destroyed and covered by sands, together with any fixed fishing facilities, well-attested for the Late Mesolithic period. There are signs that the tsunami probably occurred during late autumn, so that any stored foods meant to last over the winter may also have been lost, with subsequent starvation among survivors. It is conceivable, particularly in the context of continuing rising sea-levels at this time, that the final abandonment of the remaining remnants of Doggerland as a place of permanent habitation by Mesolithic populations was brought about by the Storegga tsunami. Following the Storegga Slide tsunami, it appears, Britain finally became separated from the continent and, in cultural terms, the Mesolithic there goes its own way.
The following map, extensively cropped from Weninger et al. (2008), show the estimated coastlines around 9000 years ago (blue line) and around 8000 years ago (red line).
Just two final remarks:
1. Tsunamis can be extremely dangerous, and may occur in places, where they were never expected.
2. Sea level rise can be an extremely serious problem for coastal and island populations.
I am not selling this as the truth and nothing but the truth, but it does seem to fit rather well with the available data, and that is more or less what science is about - it remains a working hypothesis.
Note:calBP is short for calibrated years before present, where present means the year 1950 – calibration converts dates like radiocarbon or other dates to calendar years.
Main reference:Weninger et al.
The catastrophic final flooding of Doggerland by the Storegga Slide tsunamiDocumenta Praehistorica XXXV (2008)
Freely available online at
http://sprint.clivar.org/soes/staff/ejr/Rohling-papers/2008-Weninger%20et%20al%20Documenta%20Praehistorica.pdf PS:I intend to write something about the third Storegga Slide in a forthcoming
post.
My Opera
The Danish Meteorological institute (DMI) has recently released a report that suggested that the risk of a tsunami off Danish coasts was very low. DMI predicted that a tsunami was likely to occur once every 1,000 years and that it would most likely be catalysed by a seabed shift in an area north of Scotland.
