Glacial Erosion

Glacial erosion is the process by which glaciers cut, carve, and shape the land through the actions of ice, water, and rock debris. As glaciers move, they exert tremendous force on the land and can significantly alter the landscape through various erosional processes.

Erosional Processes

• Plucking: Glaciers can "pluck" or pick up rocks and sediments as they move over the land, carrying these materials along with the ice.
• Abrasion: The scraping and grinding action of rock fragments embedded in the base of the glacier can wear away the underlying rock, creating smooth, polished surfaces.
• Roche Moutonnée: Asymmetric rock formations created by glacial erosion, with a gently sloping up-glacier side and a steep, irregular down-glacier side.
• Glacial Striations: Scratches and grooves left on the bedrock from the movement of the glacier, indicating the direction of ice flow.
• Cirque Formation: Bowl-shaped depressions carved out by glaciers at the head of a valley.
• U-shaped Valleys: Valleys that have been widened, deepened, and straightened by the erosive action of glaciers.

Study Guide

To understand glacial erosion, it's important to focus on the following key points:

1. Describe the processes of plucking and abrasion, and explain how they contribute to glacial erosion.
2. Identify and explain the formation of roche moutonnée and glacial striations as evidence of glacial erosion.
3. Discuss the formation of cirques and U-shaped valleys, and their significance in understanding glacial erosion.
4. Compare and contrast the erosional features of glacial landscapes with those formed by other agents of erosion, such as rivers and wind.
5. Examine the role of climate change and the retreat of glaciers in influencing glacial erosion processes and landforms.

By mastering these concepts, students can gain a comprehensive understanding of glacial erosion and its impact on shaping the Earth's surface.