Why do glacial landscapes exist in the UK?
Globally, cold environments cover over 25% of the World's land surface and are incredibly varied in their nature. Today in the UK current cold environments are limited to parts of Northern and upland Scotland and there is regular snow cover in winter in Aviemore.
However, there is lots of evidence in the UK that ice and glaciers in particular have helped to create our landscape in the past. The Earth has gone through a series of warm and cold periods within its history. 20,000 years ago much of the UK will have been covered in ice as part of a much larger Arctic ice sheet. Ice will have been up to 3km thick and large glaciers will have flowed down hill due to gravity. Times like these when the temperature has dropped significantly and ice advances are known as GLACIAL periods (when global temperatures drop to an average 11°C from the current 15°C). The last glacial period peaked 22,000 years ago and since 12,000 years ago we have seen warming.
Times when temperatures are warmer for extended periods of time are known as INTERGLACIALS and these periods are marked by the retreat of ice to higher altitudes or Latitudes.
As can be seen on the map ice covered a huge amount of land in the UK in the last ice age. Ice spread outwards from the Arctic to cover Canada, parts of the USA, much of Northern Europe and the UK. South of this glacial environment in the UK there would have been areas of permanently frozen ground (permafrost) and tundra vegetation which we find much further north in Europe today. Huge meltwater rivers would also have taken sediment far away from this ice environment.
As the ice shifted and advanced over the UK it would have transformed the river valleys and rounded hills underneath through various erosion, transport and deposition processes.
Glacial environment next to Mount Cook, on New Zealand’s South Island. Note the dead ice and amount of deposited glacial sediment .
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