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How did ice carve the corries, aretes and U-shaped valleys of a glaciated upland?

The formation of features in glaciated upland landscapes - corrie, arete, pyramidal peak, U-shaped valley, hanging valley, truncated spur and ribbon lake - by the processes of glacial erosion and deposition.

An SQA National 5 Geography answer on glaciated upland landscapes, explaining how glacial erosion and deposition form corries, aretes, pyramidal peaks, U-shaped valleys, hanging valleys, truncated spurs and ribbon lakes, with named UK examples.

Generated by Claude Opus 4.810 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. How glaciers erode
  3. Corries, aretes and pyramidal peaks
  4. U-shaped valleys and their features
  5. Examples in context
  6. Try this

What this dot point is asking

The SQA wants you to explain how moving ice during the last Ice Age shaped upland landscapes, and to describe and explain the formation of the main glacial features: corries, aretes, pyramidal peaks, U-shaped valleys, hanging valleys, truncated spurs and ribbon lakes. You should be able to support an answer with a labelled diagram and a named example.

How glaciers erode

Two processes do most of the work, helped by weathering above the ice.

Corries, aretes and pyramidal peaks

A corrie (also called a cwm or cirque) is an armchair-shaped hollow high on a mountain:

  1. Snow gathers in a sheltered, shaded hollow (often north- or east-facing) and compresses into ice.
  2. Plucking steepens the back wall; abrasion and rotational movement of the ice deepen the floor.
  3. When the ice melts, a deep hollow with a steep back wall and a rock lip is left, often holding a small round lake called a tarn.

When two corries erode back to back, the land between them is worn to a narrow, knife-edged ridge called an arete (for example Striding Edge in the Lake District). When three or more corries erode around a single mountain, they leave a sharp, steep-sided pyramidal peak.

U-shaped valleys and their features

A glacier flowing down a former river valley reshapes it completely:

  • It bulldozes straight ahead, so it straightens the valley and cuts off the ends of the interlocking spurs, leaving steep cliff-like truncated spurs.
  • Plucking and abrasion deepen and widen the valley into a U shape with a wide, flat floor and very steep sides.
  • Smaller tributary glaciers could not erode as deeply, so their valleys are left high up the side as hanging valleys, often with a waterfall plunging into the main valley.
  • A ribbon lake is a long, narrow lake on the valley floor, formed where the ice eroded a deeper basin or left a dam of moraine (for example Loch Lomond or Windermere).

Examples in context

Example 1. The Cairngorms. The Cairngorm plateau has corries such as Coire an t-Sneachda holding tarns, and deep U-shaped glens carved by ice, showing the full glacial sequence in the Scottish Highlands.

Example 2. The Lake District. Striding Edge is a classic arete leading to Helvellyn, and Windermere is a long ribbon lake in a glacial trough, which is why this area is used to teach glacial features.

Try this

Q1. Name the small round lake often found in a corrie. [1 mark]

  • Cue. A tarn.

Q2. State the two main processes of glacial erosion. [1 mark]

  • Cue. Plucking and abrasion.

Exam-style practice questions

Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

SQA N5 style5 marksExplain the formation of a corrie. You may use a diagram or diagrams.
Show worked answer →

A 5-mark "Explain the formation" answer rewards a sequence of linked processes, so build the corrie step by step and name the processes.

Snow collects in a hollow on a north-facing mountainside, where it is shaded and survives the summer. Year after year it compresses into ice.

The ice deepens the hollow by plucking, where ice freezes onto rock and pulls pieces away as it moves, and by abrasion, where rock frozen into the base of the ice scrapes and grinds the floor like sandpaper.

Rotational movement of the ice deepens the hollow into an armchair shape and steepens the back wall. Frost shattering above the ice sharpens the back wall further.

When the ice melts, an armchair-shaped hollow is left, often with a steep back wall and a rock lip that traps a small round lake called a tarn.

Markers reward each named process used correctly (plucking, abrasion, rotational movement, frost shattering) and a clear description of the final shape. A diagram can earn marks if it is labelled.

SQA N5 style4 marksDescribe the differences between a U-shaped valley and a V-shaped valley.
Show worked answer →

This compares two features, so each point must mention both to score, and the question links glaciated and river landscapes.

A U-shaped valley has a wide, flat floor and very steep, almost vertical sides, while a V-shaped valley has a narrow floor and gentler, sloping sides.

A U-shaped valley was carved by a glacier that bulldozed straight through the landscape, while a V-shaped valley was cut by a river eroding downwards.

A U-shaped valley often has truncated spurs (cut-off ridge ends) and hanging valleys, while a V-shaped valley has interlocking spurs that the river winds around.

Markers reward each clear comparative point, naming the shape, the process and the associated features. Describing only one valley type loses the contrast mark.

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