The palaeogeography of Northwest Europe during the last 20,000 years

Abstract

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Since the last glacial period, large vertical changes in the height of sea level relative to the land surface have led to considerable horizontal shifts in the position of coastlines around Northwest Europe. Indeed, for much of the last 20,000 years, extensive areas of the present-day shelf seabed were sub-aerially exposed due (primarily) to the glacial eustatic lowering of sea level. Accurate maps depicting these palaeogeographic changes are of great value to a wide spectrum of researchers including (inter alia) archaeologists, marine geomorphologists, climate scientists, biogeographers and palaeobotanists, although a lack of empirical sea level data has often hindered efforts to produce reliable palaeogeographic reconstructions. However, the processes which bring about change in relative sea level can be successfully simulated by computer models that describe the response of the solid Earth to the loading and unloading of glacial ice (‘glacial rebound models’). In addition to simulating relative sea-levels, the output from these models can be combined with modern day bathymetric and topographic data to produce first-order palaeogeographic reconstructions. For this publication and associated map, numerical outputs from a recently published glacial rebound model are used to produce a series of palaeogeographic maps of Northwest Europe since the Last Glacial Termination. These maps, developed using GIS tools and presented here individually at a scale of 1:20,000,000, emphasize that for much of the period from 20,000 years ago to the present, large areas of the Northwest European shelf, now covered by sea, were dry land. However, they also suggest that whilst Britain maintained a ‘land-bridge’ connection with the continent until well into the Holocene interglacial (which began 11,700 years ago), any connection between Britain and Ireland would have been low-lying, probably ephemeral and unlikely to have existed after circa 15,000 years ago.