Ice ages and ice sheets

The past 2.6 million years — known geologically as the Quaternary Period — are ones of marked landscape change brought about by global climate change. Britain, located in the north-east Atlantic region with its maritime climate, is particularly sensitive to global climate change.

Geological evidence shows that the British climate has been highly variable, ranging from periods of intense cold where significant parts of Britain were covered by ice sheets, to warmer periods where the climate was similar to the present-day Mediterranean region.

Research is focused upon examining the effects of processes operating within former cold periods (known as 'cold stages', 'glacials' or 'ice ages') on the landscape of Britain — both periglacial and glacial.

Ice age history of Britain

Glacial record of Northern Europe

Britain was glaciated on numerous occasions during the Quaternary with ice sheets extending at their maximum over two-thirds of the present British land-mass and much of the adjacent continental shelf. Several key questions emerge:

  • How many times was Britain covered by ice sheets during the Quaternary?
  • When did these glaciations occur?
  • How extensive were the glaciations?

Resolving these questions is critical to understanding the longer-term landscape history of Britain and the sensitivity of the British land-mass — and in particular the British Ice Sheet — to global climate change and whether its behaviour is synchronous with other ice sheets adjacent to the North Atlantic region.

Currently, research is being undertaken on terrestrial and offshore sites around East Anglia, Cumbria and Wales to determine the number of different glaciations that affected these areas, when they occurred, and how extensive they were. Research is also investigating evidence for Early Pleistocene glaciations around the North Sea Basin through the examination of anomalous erratic and heavy mineral clusters.

Flow behaviour of the British Ice Sheet

Ice sheets are a critical part of the climate system with many scientists now recognising that ice sheets do not just respond to climate change, but can also drive climate change. However, understanding how ice masses behave is one of the key challenges facing the scientific community, not least because many of the processes that control their behaviour operate at the base of ice masses e.g. subglacial hydrology and subglacial deformation. Whilst some scientists use sophisticated geophysical techniques to determine what is happening at the base of modern ice masses, an alternative approach is to examine the geological and geomorphological record left behind by ancient ice sheets. Our studies on ice sheet behaviour and subglacial regimes focus on the Middle and Late Pleistocene North Sea and Irish Sea sectors of the British Ice Sheet.

In northern East Anglia a team of scientists is examining Middle Pleistocene glacial environments and processes along the north Norfolk coast. A stepped retreat of the southern margins of the British Ice Sheet from this area left a series of recessional ice-marginal landforms and complex glaciotectonic structures. The glaciotectonic structures reveal the highly significant role temporal and spatial variations in water content within the subglacial bed played in controlling the ice-marginal dynamics.

In Anglesey, scientists are examining the landform and geological record to determine the behaviour of part of the Irish Sea sector of the Late Pleistocene British Ice Sheet. In particular, attention is being focussed on the amount of bedrock control there was on the development of apparent glacially-streamlined subglacial bedforms.

Contact

Contact Dr Jonathan Lee or Dr Emrys Phillips for further information.