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

Smaller side valleys that hangs high above the floor of a larger main valley

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?

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 the three main scales of glacial landforms?

Answer 9

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

Question 10

What is glacial erosion?

Answer 10

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

Question 11

What is glacial debris entrainment?

Answer 11

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

Question 12

What is glacial deposition?

Answer 12

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

Question 13

List 7 macro-scale landforms

Answer 13

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

Question 14

List 5 meso-scale landforms

Answer 14

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

Question 15

List 2 micro-scale landforms

Answer 15

striations, erratics.

Question 16

Explain how a Corrie is formed in 7 steps (Hint: NIPCAMT)

Answer 16

1. Nivation starts the hollow through freeze-thaw weathering.
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 17

Can you give 2 features of a Corrie?

Answer 17

• Often N or NE facing in the northern hemisphere as this direction will receive the least sunlight.
• Size varies but they are often around 0.5km in diameter with a back wall up to 1000m in height.

Question 18

What is a ribbon lake?

Answer 18

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

Question 19

How does a glacial trough form in 5 steps? (VEUCS)

Answer 19

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 20

Explain how a ribbon lake is formed in 3 steps? (UOB)

Answer 20

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 21

Explain how a rouches moutonnees are formed in 4 steps? (OUDA)

Answer 21

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 22

Explain how a lateral moraine is formed in 3 steps? (WSH)

Answer 22

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 23

Explain how a medial moraine is formed in 3 steps? (LDR)

Answer 23

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 24

Explain how end moraines are formed in 5 steps? (SFRPA)

Answer 24

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 25

Explain how a drumlin is formed 4 steps? (UBSC)

Answer 25

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 26

What are the 2 types of till?

Answer 26

- 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 27

What is another name for till deposits?

Answer 27

Boulder clay

Question 28

What is a till plain?

Answer 28

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

Question 29

How is a hanging valley formed in 4 steps? (TLDW)

Answer 29

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.