Glacial processes

The last ice age in the UK took place around 18,000 years ago. During this time, temperatures remained low throughout the year and ice sheets and glaciers covered the north of the UK and other parts of Europe.

Most of northern Europe was covered in ice during the Ice Age, including most of the British Isles and Scandinavia.

Glaciers shape the land through processes of erosion, weathering, transportation and deposition, creating distinct landforms.

Hunting for evidence of glaciers in the Lake District and identifying glacial landforms

Erosion

The two main types of erosion are:

  • Abrasion - as the glacier moves downhill, rocks that have been frozen into the base and sides of the glacier scrape the rock beneath. The rocks scrape the bedrock like sandpaper, leaving scratches called striations behind.
  • Plucking - rocks become frozen into the bottom and sides of the glacier. As the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.

Weathering

Freeze-thaw weathering is the main type of weathering. During the day when temperatures are higher, the snow melts and water enters the cracks in the rock. When the temperature drops below 0°C the water in the crack freezes and expands by about 9 per cent. This makes the crack larger. As this process is repeated through continual thawing and freezing the crack gets larger over time. Eventually pieces of rock break off.

Glaciers can be affected by freeze-thaw weathering, plucking and abrasion.