Glacial Landforms

Question 1

What is a Corrie?

Answer 1

an armchair-shaped, steep-sided hollow at the head of a glaciated valley.

Question 2

What are arêtes and pyramidal peaks?

Answer 2

Aretes are formed by 2 Corries
Pyramidal peaks are formed by 3 Corries

Question 3

What are glacial troughs?

Answer 3

Former V-shaped river valleys widened and deepened by glaciers (making them into U-shaped valleys)

Question 4

What are hanging valleys?

Answer 4

Former V-shaped river valleys widened and deepened by glaciers (making them into U-shaped valleys)

Question 5

What is a roche moutonnée?

Answer 5

isolated rocks, generally between 5 to 30m in height, along the base of a glaciated valley. They are characteristically smooth on one side and jagged on another.

Question 6

What are the 3(or 4) different types of moraines?

Answer 6

• Lateral Moraine
• Medial Moraine
• End Moraine (Terminal/Recessional)

Question 7

What are drumlins? (Give 3 facts)

Answer 7

• Oval-shaped hills of glacial till found in swarms (basket of eggs topography).

Question 8

What is a till?

Answer 8

the unconsolidated sediment deposited by a glacier - it is a mix of clay, boulders and gravel.

Question 9

What are subglacial and ice-marginal landscapes?

Answer 9

• Subglacial: Formed under ice masses, dominated by erosion (e.g., glacial troughs).
• Ice-marginal: Formed at glacier edges, dominated by deposition (e.g., moraines).

Question 10

What are proglacial and periglacial environments?

Answer 10

• Proglacial: Found in front of glaciers, where meltwater and wind action shape the landscape.
• Periglacial: Cold environments near but not under glaciers, featuring permafrost.

Question 11

What are the three main scales of glacial landforms?

Answer 11

• Macro-scale
• Meso-scale
• Micro-scale

Question 12

What is glacial erosion?

Answer 12

removal of rock material by ice through abrasion, plucking and meltwater flow from ice margins.

Question 13

What is glacial debris entrainment?

Answer 13

When sediment is being incorporated into glacial ice and carried along with the ice.

Question 14

What is glacial sediment transport?

Answer 14

sediment on top of (supraglacial), within (englacial) or at the base (subglacial) of ice being moved.

Question 15

What is glacial deposition?

Answer 15

sediment on top of (supraglacial), within (englacial) or at the base (subglacial) of ice being moved.

Question 16

List 7 macro-scale landforms

Answer 16

corries (cirques), aretes, pyramidal peaks, glacial troughs, ribbon lakes, till plains, end-moraines

Question 17

List 5 meso-scale landforms

Answer 17

roches moutonnees, drumlins, kames, eskers, kettle holes.

Question 18

List 2 micro-scale landforms

Answer 18

striations, erratics.

Question 19

Explain how a Corrie is formed in 7 steps

Answer 19

1. Nivation starts the hollow through freeze-thaw weathering and snowmelt erosion.
2. Ice builds up, and rotational slip and abrasion deepen the hollow.
3. The glacier pulls away from the back wall, plucking loosened rock.
4. A bergschrund (crevasse) forms between the ice and back wall.
5. Debris falls in and gets trapped under the ice, causing more abrasion.
6. At the front, less erosion leads to moraine building up into a lip.
7. After the glacier melts, meltwater collects to form a tarn (corrie lake).

Question 20

Can you give 3 features of a Corrie?

Answer 20

• Often N or NE facing in the northern hemisphere as this direction will receive the least sunlight.
• They are in the lee of prevailing winds, causing the snow to accumulate for longer.
• Size varies but they are often around 0.5km in diameter with a back wall up to 1000m in height.

Question 21

What is a ribbon lake?

Answer 21

Formed when glaciers over-deepen sections of valleys, which later fill with water.

Question 22

How does a glacial trough form in 5 steps?

Answer 22

1. A glacier moves through a V-shaped river valley.
2. It erodes the valley floor and sides by abrasion and plucking, making it wider and deeper.
3. This creates a U-shaped valley with steep sides and a flat floor — the glacial trough.
4. The glacier cuts off interlocking spurs, leaving behind truncated spurs.
5. At the upper end, a steep trough end forms where the glacier once entered from corries.

Question 23

Explain how a ribbon lake is formed in 3 steps?

Answer 23

1. Glacial erosion is uneven — areas of softer rock are eroded more deeply.
2. This creates an over-deepened hollow or rock basin in the valley floor.
3. After the glacier melts, the basin fills with water, forming a long, narrow ribbon lake.

Question 24

Explain how a rouches moutonnees are formed in 4 steps?

Answer 24

1. A glacier moves over a hard rock outcrop.
2. On the upstream side, the glacier smooths the rock by abrasion, often leaving striations (scratch marks).
3. As the glacier flows over the top, it plucks loose rock on the downstream side, creating a rough, jagged slope.
4. This creates an asymmetrical feature with a smooth, gentle slope facing up-valley and a steep, rough slope facing down-valley.

Question 25

Explain how a lateral moraine is formed in 3 steps?

Answer 25

1. Weathering and mass movement cause rock debris to fall from the valley walls onto the edge of a glacier. 2. This debris builds up along the sides of the glacier, forming lateral moraines. 3. As the glacier melts (deglaciates), the debris is left behind in a hummocky ridge along the valley edges.

Question 26

Explain how a medial moraine is formed in 3 steps?

Answer 26

1. When two valley glaciers merge, their lateral moraines join. 2. This forms a medial moraine — a line of debris running down the centre of the new, larger glacier. 3. After deglaciation, the debris is left as a ridge in the middle of the valley floor.

Question 27

Explain how end moraines are formed in 5 steps?

Answer 27

1. End moraines form at the snout of a glacier when it melts and deposits sediment. 2. A terminal moraine marks the furthest point the glacier reached. 3. It forms a ridge of debris dumped at the glacier’s snout. 4. A recessional moraine forms when the glacier pauses during retreat, leaving more debris. 5. These moraines can be arc-shaped, tens of metres high, and kilometres long.

Question 28

Explain how a drumlin is formed 4 steps?

Answer 28

1. The exact process is uncertain, but a leading theory explains it through sediment strength. 2. Beneath a glacier, sediments with different strengths respond differently to the pressure of moving ice. 3. Stronger sediments resist deformation and act as cores. 4. These cores shape into streamlined hills, called drumlins, as the ice flows over them.

Question 29

What are the 2 types of till?

Answer 29

- Lodgement till is deposited under the ice and is usually structureless. - Ablation till is deposited by melting ice and usually has some evidence of deposition by running meltwater.

Question 30

What is another name for till deposits?

Answer 30

Boulder clay

Question 31

What is a till plain?

Answer 31

a large, flat or gently sloping area formed by the deposition of glacial till, which is unsorted sediment deposited directly by glacial ice.

Question 32

How is a hanging valley formed in 4 steps?

Answer 32

1. A tributary glacier flows into a larger main glacier. 2. The smaller glacier erodes less deeply because it’s blocked or has less power. 3. After glaciation, the main valley is much deeper, leaving the tributary valley ‘hanging’ above. 4. Waterfalls often flow from the hanging valley into the main glacial trough.