Glacial Processes Lab

Ice, the slow sculptor

Thousands of years ago, thick glaciers covered the uplands of Britain. As the ice crept downhill it carved out the dramatic peaks, ridges and valleys we see today. This lab looks at how glaciers erode, transport and deposit rock, and at the landforms they leave behind in places such as the Lake District.

The language of ice

Four ideas run through this module:

How freeze-thaw works

Put the stages of freeze-thaw weathering into the right order.

• Water collects in a crack in the rock
• The temperature falls and the water freezes, expanding
• The expanding ice pushes the crack wider
• The ice thaws and the cycle repeats many times
• A fragment breaks off and falls as scree

Name the process

Rock fragments frozen into the base of a glacier scrape and smooth the valley floor as the ice moves over it. What is this process called?

• Abrasion
• Plucking
• Freeze-thaw weathering
• Deposition

Two families of landform

Glaciers both wear the land away and dump material. The landforms differ in how they form and where they are found.

Match each erosional landform

Case study: the Lake District

The Lake District is a distinctive UK glaciated upland landscape. Ice once carved its corries, knife-edge ridges and deep U-shaped valleys, many now filled by long ribbon lakes. Its dramatic scenery makes it significant for water supply, hill farming and tourism, and those competing uses shape how the landscape is looked after today.

Spot the erosional landforms

Select the TWO erosional landforms.

• A corrie
• An arete
• A drumlin
• A terminal moraine

Match each depositional landform

Glacial processes in words

As a glacier moves it erodes by _____, freezing onto and pulling away loose rock, and by _____, grinding the valley with embedded fragments. High in the uplands it carves an armchair hollow called a _____. Lower down, when the ice melts, it drops material known as _____. A valley widened by ice has a _____-shaped cross-section.

Where would you find them?

Where would you expect to find depositional landforms such as moraines and drumlins?

• On gentler, lower ground where the ice melted
• On the steepest, highest mountain peaks
• Only deep beneath the sea
• Inside the corries near the summits

Glacial processes

Tap the TWO statements that are TRUE.

• Plucking is ice freezing onto rock and pulling it away as the glacier moves.
• Erosional landforms are found in the steep, high parts of the uplands.
• A drumlin is carved by ice plucking rock from a mountainside.
• Abrasion is the process of melting ice dropping its load of material.
• A corrie is a ridge of material left at the snout of a glacier.

Name that landform

Identify three glaciated landforms from their descriptions.

• A knife-edge ridge separates two armchair-shaped hollows. What is the ridge?
• A wide valley has a flat floor and steep sides, unlike a river valley with its V shape. How did it form?
• At the point where a glacier finally stopped, a ridge of dumped rock and till was left. What is it?

How a corrie forms

Explain how a corrie is formed by glacial erosion. Then explain the difference between erosional and depositional glacial landforms, using named examples.

• Explain how snow collects and compacts into ice in a hillside hollow
• Explain how plucking and abrasion deepen the hollow into an armchair-shaped corrie
• Explain that erosional landforms, such as corries and aretes, are found in steep, high uplands
• Explain that depositional landforms, such as moraines and drumlins, form on gentler, lower ground where the ice melted