GLACIAL LANDSCAPES

Formation of erosional and depositional features in glaciated landscapes:

1. Corrie

2. Arête

3. Pyramidal peak

4. U-shaped valley

5. Hanging valley

6. Ribbon lake

7. Drumlin 

8. Esker 

9. Terminal moraine 

GLACIAL FORMATION

1. I can explain how a glacier is formed:

Form in a North facing hollow as more shade (1)

When more snow falls in winter than melts in the summer (1)

Snow compresses to form neve and then glacial ice (1)

Moves downhill due to its own weight and gravity (1)

Can you watch the following sections:
Neve formation 5:37 – 7:54 minutes 

https://www.twigscotland.com/film/glaciers-1096/
2.39 minutes

GLACIAL PROCESSES

2. I can explain how a glacier erodes and shapes the landscape by the processes of:

1.Plucking

2.Abrasion

3.Freeze - Thaw

1 – Plucking:
when ice freezes onto bedrock and rips this out (1) making the valley / corrie steeper (1).

2 – Abrasion:
when angular rock embedded in the glacier grinds the bedrock (1) making it deeper (1).

3 - Freeze – Thaw:
water in rock cracks expands when it freezes (1), repeated expansion weakens and breaks the rock (1).

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1. Corrie

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Rotational sliding over deepens the central part of the hollow (1)

Friction causes ice to slow at the front edge allowing a rock lip to form (1)

Once the glacier has melted this hollow can fill with water to form a Corrie Loch or Tarn (1)

An example of this is Red Tarn in the Lake District (1)

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https://timeforgeography.co.uk/videos_list/glaciation/corries/
1.54 minutes 

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2. Arete

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Rotational sliding over deepens the central part of the corrie (1)

When two corrie form back to back a narrow ridge is formed in-between (1)

Further frost shattering will make the ridge narrower and scree slopes may form (1)

An example of this is Striding Edge in the Lake District (1)

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https://timeforgeography.co.uk/videos_list/glaciation/Aretes/
1.28 minutes

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3. Pyramidal Peak

Rotational sliding over deepens the central part of the hollow (1)

When three or more corrie erode back to back it forms a pyramidal peak (1)

Further frost shattering will make the peak more pointed and scree slopes may form (1)

An example of this is Helvellyn in the Lake District (1)

https://timeforgeography.co.uk/videos_list/glaciation/Pyramid-peaks/
1.15 minutes

LITHOSPHERE: GLACIATION 1

Explain the conditions and processes involved in the formation of a corrie.
You may wish to use an annotated diagram or diagrams.

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4. U-shaped Valley

Following the existing v shaped river valleys (1)

Former interlocking spurs may be cut off by glacier (1) leaving crags or exposed rock faces at the sides of the valley (1). Resulting in steep/crags truncated spurs(1).

Over time the valley becomes straightened widened and deepened(1). After glaciation the previous river may return called a misfit stream(1). The valley sides are steep and the floor is flat and wide (1).

An example is Great Langdale Valley in the Lake District (1).

https://timeforgeography.co.uk/videos_list/glaciation/formation-of-U-shaped-valleys/
4.17 minutes 

5. Hanging Valley

Smaller tributary glaciers have less powerful (1) glaciers which do not erode as deeply (1). 

These smaller valleys are left “hanging” over the main u-shaped valley floor (1). Often leads to a waterfall forming (1) (although a different process to one formed by rivers)

Interlocking spurs are truncated by the power of the glacier (1), leaving crags or exposed rock faces at the sides of the valley (1).

An example of a Hanging Valley is Little Langdale (1).

6. Ribbon Lake

Following the existing v shaped river valleys(1).

Former interlocking spurs may be cut off by glacier(1), resulting in steep/crags truncated spurs(1).

Over time the valley becomes straightened widened and deepened(1).

Ribbon lakes form where softer bedrock is eroded more deeply than the surrounding area (1). Or can form where a terminal or recessional moraine creates a dam(1).

An example is Lake Windermere (1).