The World Under Ice
🧊 The World Under Ice
That ice sheet disappeared roughly 10,000 years ago as the climate warmed at the end of the last Ice Age. But the landscape it carved is still here. The dramatic U-shaped valleys of the Lake District. The jagged arêtes of Snowdonia. The ribbon lakes of Scotland. The flat till plains of the English Midlands. Every one of these features is the product of glacial processes — erosion, transport, and deposition carried out over tens of thousands of years. Understanding these processes is not just academic: it is the key to reading the entire British landscape, and to understanding why glacial environments look and behave as they do anywhere on Earth.
Right now, glaciers cover roughly 10% of Earth's land surface. As the climate warms, almost all of them are retreating — and the same processes that shaped Britain's past are playing out today in the Alps, the Himalayas, Greenland, and Antarctica. This topic explains exactly how they work.
Geography glossary
- What is firn (névé)?
- Partially compacted, granular snow that forms the intermediate stage between fresh snow and dense glacial ice.
A glacier is a large, persistent body of ice that forms on land through the compaction and recrystallisation of snow over many years. Glaciers are not static — they flow slowly downhill under the force of gravity. They are, in effect, rivers of ice, and like rivers they erode, transport, and deposit material as they mo
Earn the mark scheme marks
🧠 ICE CAPS — Remembering the Glacial Process Sequence
Use this mnemonic to remember the key glacial processes in order, from ice formation through to deposition:
You can also remember the two erosion processes with: "Plucking Pulls, Abrasion Scratches" — Plucking produces a jagged surface (it pulls blocks out); abrasion produces a scratched, polished surface.
For moraine types: TLMRG — Terminal (furthest advance), Lateral (valley sides), Medial (two glaciers merge), Recessional (retreat stages), Ground (under the ice). Or use the sentence: "The Lonely Mountain Range Guards [the valley]".
Quick Check: A sample of glacial sediment contains boulders, sand, silt, and clay all mixed together with no layering. Is this till or fluvioglacial sediment? How do you know?
This is till. The key evidence is that it is unsorted (boulders mixed with clay and silt) and unstratified (no layering). Till is deposited directly by ice, which has no capacity to sort by particle size — when ice melts, all particle sizes are dropped together regardless of their mass. Fluvioglacial sediment deposited by meltwater would be sorted (larger particles deposited first, finer particles carried further) and stratified (distinct horizontal layers). If this sediment were fluvioglacial, you would see separate layers of boulders, then gravel, then sand, then silt — not everything mixed together.
Now try it yourself
Quiz · Question 1 of 15
What term describes the zone in a glacier where ice is lost through melting, evaporation and calving?
Tap an answer to check it