Erosion, Transport, and Deposition by Glaciers
- Imagine standing in a valley surrounded by towering mountains.
- The landscape is shaped by glaciers—massive rivers of ice that erode, transport, and deposit materials as they move.
These processes create some of the most dramatic landforms on Earth.
Glacial Erosion: Carving the Landscape
1. Plucking
- Plucking occurs when a glacier freezes onto rocks and pulls them away as it moves.
This process creates striations (scratch marks) and polished rock surfaces.
Plucking and abrasion work together to deepen and widen valleys, transforming them into U-shaped glacial troughs.
Glacial Transport: Moving the Load
- Glaciers transport debris, known as moraine, in three main ways:
1. Supraglacial
- Debris is carried on top of the glacier, often from rockfalls or avalanches.
2. Englacial
- Debris is trapped within the ice, carried along as the glacier moves.
3. Subglacial
- Debris is dragged along the base of the glacier, contributing to erosion through abrasion.
The debris transported by glaciers is unsorted and ranges from fine silt to massive boulders, all of which play a role in shaping the landscape.
Glacial Deposition: Leaving a Legacy
- When glaciers melt or retreat, they deposit the debris they have carried.
- This process creates distinctive landforms.
1. Till
- Unsorted and angular material deposited directly by the glacier.
- It includes a mix of boulders, pebbles, and clay.
