Glacial landscapes · GCSE Geography

Ice in the past

During the last glacial period, ice sheets covered much of the UK, especially Scotland, northern England and Wales. The ice melted about 12,000 years ago, leaving glacial landforms behind.

Freeze–thaw weathering: water in cracks freezes and expands, breaking pieces off the rock.
Erosion: plucking (ice freezes onto rock and pulls pieces away as it moves) and abrasion (rocks frozen into the base of the glacier scrape the bedrock like sandpaper).
Movement: rotational slip (ice moves in a curved motion in a hollow) and bulldozing (the ice pushes debris in front of it).
Transportation and deposition: glaciers carry rock debris, called moraine, and drop it when the ice melts. Till is unsorted material dropped by the ice; outwash is sand and gravel sorted and dropped by meltwater.

Erosion: corries (armchair-shaped hollows, often holding a lake called a tarn), arêtes (knife-edged ridges between two corries), pyramidal peaks (three or more corries back to back), glacial troughs (U-shaped valleys), truncated spurs, hanging valleys (often with waterfalls) and ribbon lakes (long, narrow lakes in troughs).
Transportation and deposition: erratics (boulders carried far from where they came from), drumlins (egg-shaped hills of till), and moraines: lateral (along the sides of the glacier), medial (in the middle, where two glaciers meet), terminal (at the snout) and ground moraine (spread across the valley floor).

Helvellyn: Red Tarn lies in a corrie, with the arêtes Striding Edge and Swirral Edge on either side. Ullswater and Windermere are ribbon lakes in glacial troughs.
Land use: sheep farming on the fells, forestry, slate quarrying, tourism and conservation. The Lake District is a national park and a World Heritage Site.
Tourism brings money and jobs, but also footpath erosion, traffic congestion, and high house prices caused by second homes.
Management: the Fix the Fells project repairs eroded paths; car parks, park-and-ride and bus services reduce traffic; the national park controls where new development can go.

Corrie: An armchair-shaped hollow on a mountainside, carved by ice.
Arête: A knife-edged ridge between two corries.
Pyramidal peak: A pointed peak formed where three or more corries meet.
Glacial trough: A steep-sided, flat-bottomed U-shaped valley carved by a glacier.
Hanging valley: A tributary valley left high above a glacial trough.
Ribbon lake: A long, narrow lake in a glacial trough.
Plucking: Ice freezing onto rock and pulling pieces away.
Moraine: Rock debris carried and deposited by a glacier.
Drumlin: An egg-shaped hill of till.
Erratic: A boulder carried by ice far from where it came from.