AQA · A-Level · Geography
Course version: 7037 · Version from Sept 2018
Geomorphological processes – weathering: frost action, nivation; ice…
Full specification wording
Systems and processes: Geomorphological processes – weathering: frost action, nivation; ice movement: internal deformation, rotational, compressional, extensional and basal sliding; erosion: plucking, abrasion; transportation and deposition.
Glacial landscapes are shaped by complex geomorphological processes.
Checked against the AQA 7037 specification (opens in a new tab) on .
- Point 4 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Glacial landscapes are shaped by complex geomorphological processes. Weathering includes frost action, where water freezes and expands in rock joints, and nivation, combining freeze-thaw and meltwater removal beneath snow patches. Ice movement occurs via internal deformation (ice crystals sliding) and basal sliding where meltwater lubricates the bed. Movement can be rotational in corries, compressional where ice slows, or extensional where it accelerates. Erosion is driven by plucking, where ice freezes to bedrock and pulls fragments away, and abrasion, where entrained debris acts like sandpaper. Glaciers transport material supraglacially, englacially, or subglacially, depositing it as unsorted till when the ice melts.
What earns the marks
- Explain how frost action and nivation weaken bedrock, preparing it for subsequent glacial erosion.
- Distinguish between internal deformation in cold-based glaciers and basal sliding in warm-based glaciers.
- Describe how compressional flow leads to ice thickening and overdeepening, while extensional flow causes thinning and crevassing.
- Detail the mechanisms of plucking and abrasion, linking them to the formation of specific macro and micro landforms.
Common mistakes and how to put them right
Confusing plucking with abrasion.
Put it right: Plucking involves freezing to and pulling rock away, whereas abrasion is the sandpaper effect of entrained debris.
Stating that glaciers only move by sliding.
Put it right by explaining that internal deformation is a key movement mechanism, especially in cold-based glaciers.
Assuming glacial deposition is always sorted.
Put it right by noting that direct glacial deposition (till) is unsorted and unstratified, unlike fluvioglacial deposits.
Exam tips
- Use specific terminology such as 'compressional flow' and 'extensional flow' when describing changes in glacier gradient.
- Link weathering processes like nivation directly to the early stages of corrie formation to demonstrate synoptic understanding.
- When discussing erosion, always mention the role of basal meltwater and entrained debris in facilitating abrasion.
Try the lesson
The start of the Systems and processes: Geomorphological processes – weathering: frost action, nivation; ice movement: internal deformation, rotational, compressional, extensional and basal sliding; erosion: plucking, abrasion; transportation and deposition. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of the following best describes the process of nivation in a glacial environment?
Listen
Glacial landscapes are shaped by complex geomorphological processes. Weathering includes frost action, where water freezes and expands in rock joints, and nivation, combining freeze-thaw and meltwater removal beneath snow patches. Ice movement occurs via internal deformation (ice crystals sliding) and basal sliding where meltwater lubricates the bed. Movement can be rotational in corries, compressional where ice slows, or extensional where it accelerates. Erosion is driven by plucking, where ice freezes to bedrock and pulls fragments away, and abrasion, where entrained debris acts like sandpaper. Glaciers transport material supraglacially, englacially, or subglacially, depositing it as unsorted till when the ice melts. A strong answer earns marks for these points. Explain how frost action and nivation weaken bedrock, preparing it for subsequent glacial erosion. Distinguish between internal deformation in cold-based glaciers and basal sliding in warm-based glaciers. Describe how compressional flow leads to ice thickening and overdeepening, while extensional flow causes thinning and crevassing. Detail the mechanisms of plucking and abrasion, linking them to the formation of specific macro and micro landforms. A common slip: Stating that glaciers only move by sliding. Instead, explaining that internal deformation is a key movement mechanism, especially in cold-based glaciers. Exam tip: Use specific terminology such as 'compressional flow' and 'extensional flow' when describing changes in glacier gradient.
See it
Key words
Say what each word means before you turn the card.
Frost action
Try answering aloud or in your head before turning the card.
Nivation
Try answering aloud or in your head before turning the card.
Internal deformation
Try answering aloud or in your head before turning the card.
Basal sliding
Try answering aloud or in your head before turning the card.
See every definition
- Frost action
- Water freezes and expands in rock joints, weakening the bedrock.
- Nivation
- Combines freeze-thaw and meltwater removal beneath snow patches.
- Internal deformation
- Ice crystals slide within the ice as a mechanism of ice movement.
- Basal sliding
- Meltwater lubricates the bed, allowing the ice to move.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Systems and processes: Geomorphological processes – weathering: frost action, nivation; ice movement: internal deformation, rotational, compressional, extensional and basal sliding; erosion: plucking, abrasion; transportation and deposition.
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge