Formation of Glaciated Upland Mountain Features

Key Features

1. Corrie

   • Large hollow on the side of a mountain
   • Formed by glacial erosion

2. Arête

   • Knife-edge ridge
   • Formed when two corries run back to back

3. Pyramidal Peak

   • Formed where three or more corries and arêtes meet

Formation Processes

1. How are Corries Formed?

• Initial Stage: Snow gathers in mountain hollows, especially north-facing ones, and compacts into ice.
• Downhill Movement: Ice moves, sticking to rock surfaces and steepening back walls.
• Erosion: Ice acts like sandpaper, deepening the hollow.
• Formation of a Lip: Ice movement leads to less erosion at the front, forming a lip.
• Final Stage: Glacier melts, leaving a corrie lake (or loch).

2. How are Arêtes Formed?

• Erosion: Two corries form back to back; glacier erosion brings the back walls closer.
• Development: Continued erosion narrows the ridge, creating steeper edges.

3. How are Pyramidal Peaks Formed?

• Initial Meeting: Three or more corries and arêtes erode backward towards each other.
• Erosion Processes: Includes plucking and abrasion.
• Freeze Thaw Weathering: Weathers the mountain top, creating a sharply-pointed summit.

Visual Aids

• Images: Include diagrams and images of corries, arêtes, and pyramidal peaks to enhance understanding.

Sample Questions

1. How is a corrie formed?
2. How is a pyramidal peak formed?

Recap

• Corries, arêtes, and pyramidal peaks are significant features in glaciated upland areas, formed through distinct processes of glacial erosion and weathering.