Glacial landforms and processes dramatically shape Earth's landscapes through powerful erosional and depositional forces over thousands of years.
Glacial erosion occurs through three main processes: abrasion (where rocks frozen in ice scrape against bedrock), plucking (where ice freezes around rocks and pulls them away), and bulldozing (where glaciers push material forward like a bulldozer). These processes create distinctive features in mountainous regions. A corrie (also called a cirque) forms when snow accumulates in a hollow and compresses into ice, gradually eroding a curved depression into the mountainside. As glaciers move downhill, they carve U-shaped valleys and create sharp ridges called arêtes where two glacial valleys meet.
Glacial deposition happens when ice melts and deposits its load of rock debris. This creates various landforms including moraines (ridges of deposited material), drumlins (elongated hills of glacial debris), and erratics (large boulders transported by ice). In glaciated landscapes, you can see clear evidence of both erosional and depositional processes working together. For example, when glaciers retreat, they often leave behind scattered deposits of rock material called till, while the underlying bedrock shows signs of scratching and smoothing from glacial erosion. Famous examples of glaciated landscapes can be found in the Scottish Highlands, the Alps, and North American mountain ranges, where features like corries, U-shaped valleys, and moraines dominate the terrain. These landforms tell the story of how massive ice sheets and valley glaciers once covered these areas during past ice ages, demonstrating the immense power of glacial processes in shaping our planet's surface.
