Glacial processes - shaping the land
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.
Glaciers shape the land through processes of The wearing away of pieces of rock, soil or other solid materials., The breaking down of rocks in situ by the action of weather, plants, animals and chemical processes. , To move objects or people from one place to another. and When material is deposited or left behind, eg when a river loses its energy and is unable to carry its load any further, or waves move sand onto a beach but lack the energy to carry it away., creating distinct landforms.
Hunting for evidence of glaciers in the Lake District and identifying glacial landforms
Erosion
The two main types of erosion are:
- A type of glacial erosion that occurs when rock fragments that are frozen into the bottom of a glacier scrape and erode the valley floor. - 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.
- A type of glacial erosion that occurs when ice freezes onto the landscape, ripping out rocks when it moves. - 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
When water in rocks freezes and expands, breaking the rock apart. 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.