Formation of Glacial Features: Arête

This page focuses on the formation of an arête, a sharp ridge of rock created by glacial erosion.

The process of arête formation is described in three stages:

1. Before: Snow accumulates in north-facing hollows where there is less sun exposure.

2. During: Over time, snow compresses to form ice, eventually creating glaciers on two sides of the mountain. These glaciers move downhill due to their weight and gravity.

3. After: As the glaciers move, they erode the hollow through plucking and abrasion. When two corries (bowl-shaped hollows) form back to back, they create an arête.

Example: Striding Edge is provided as an example of an arête.

Vocabulary: An arête is a sharp, knife-edge ridge formed when two corries erode back to back.

This explanation provides a clear understanding of how glacial landforms are formed, specifically focusing on the creation of arêtes in glaciated landscapes.

Introduction to Glaciation

Glaciation is the process of land being covered by ice sheets or glaciers. This section introduces the concept of glaciation and its impact on global temperatures.

Definition: Glaciation is the process of being covered by ice sheets (glaciers).

The document highlights that during periods of glaciation, temperatures were approximately 6°C colder than present day across most of the globe.

Processes of Glacial Erosion

This section details the three main processes of glacial erosion:

1. Freeze-Thaw: This process involves water entering cracks in rocks, freezing, and expanding, which causes the rock to shatter.

2. Plucking: Ice freezes onto rocks and pulls chunks out as the glacier moves.

3. Abrasion: Rocks frozen to the bottom and sides of the glacier scratch and scrape at surrounding rocks, similar to sandpaper.

Highlight: These three processes - freeze-thaw, plucking, and abrasion - are fundamental to understanding how glacial landforms are formed.

A diagram illustrates the cross-section of a glacier, showing how these processes work in conjunction to erode the landscape.

Formation of Glacial Features: Corrie

This page details the formation of a corrie, another significant glacial landform.

The process of corrie formation is described in three stages:

1. Before: Snow accumulates in a north-facing hollow, where shade allows the snow to remain longer.

2. During: Over time, the snow compacts and forms ice. Due to gravity and its own weight, the glacier begins to move downhill, eroding the hollow through plucking and abrasion.

3. After: The erosion process creates a steep, rugged backwall and a smooth, flat bottom. Sometimes, a lochan (small lake) forms due to a lip preventing meltwater from escaping.

Vocabulary: A corrie is a bowl-shaped hollow formed by glacial erosion on the side of a mountain.

Highlight: Abrasion creates a smooth, flat bottom, while plucking forms the steep, rugged backwall of the corrie.

This explanation provides a comprehensive understanding of how a corrie is formed, which is a key concept in glacial processes and landforms.