Geog notes

FORMATION OF A CORRIE

1. Neve Formation

• Snow accumulates in a hollow, usually facing north east. This snow withstands summer temperatures and builds up in layers. Increasing the weight of the snow, compacting lower layers to form a neve.

2. Nivation

• Nivation - a combination of freeze-thaw, weathering and melt water erosion - deepens the hollow

3. Further accumulation

• Further accumulation results in the removal of air from the neve to form ice. The largest mass of ice is at the back of the glacier which pushes it downwards, lifting the snout up. This is called rotational slip.

4. Rotation slip

• Rotation slip causes plucking of the back wall and abrasion of the base

5. Bergschrund

• The rotational slip promotes the formation of a large crack at the back of a glacier called the Bergschrund. Material from freeze-thaw & weathering above the glacier collectes and is dragged beneath the glacier by rotational slip, furthering abrasion.

6. Extensional and Compressional Flow

• Extensional flow results in the formation of crevasses at the back of the glacier which also collects debris and transfers it deep into the glacier to be used in erosion. Compressional flow occurs at the front where the rock lip restricts flow.

7. Overflow

• The corrie finally overflows out of the hollow, resulting…