Glaciers are powerful agents of erosion, transportation, and deposition, shaping the landscape in distinct ways.
Table of Contents
Erosion
Plucking: Glaciers freeze onto rocks and as they move, they pull chunks of rock away.
Abrasion: Rocks and debris embedded in the glacier's base scrape against the bedrock, smoothing and polishing it.
Example: The fjords of Norway, deep and steep-sided valleys formed by glacial erosion.
Transportation
Supraglacial: Material carried on the surface of the glacier.
Englacial: Material trapped within the ice.
Subglacial: Material carried at the base of the glacier.
Example: The movement of large boulders (erratics) far from their origin points.
Deposition
Till: Unsorted debris dropped by a melting glacier.
Moraines: Accumulations of dirt and rocks at the edges or end of a glacier.
Outwash Plains: Sorted sediments deposited by meltwater streams.
Example: The Great Plains in North America, largely formed from glacial deposits.
Examples in Detail
Fjords: These are created when glaciers carve deep valleys that are later filled with seawater. The Sognefjord in Norway is a prime example.
Erratics: These large rocks, like those found in Central Park, New York, were transported and deposited by glaciers from as far as Canada.
Moraines: The terminal moraine of the Laurentide Ice Sheet, which can be seen on Long Island, New York, shows the extent of glacial deposition.
Summary
In summary, glaciers sculpt the earth through a combination of erosion, transportation, and deposition, leaving behind a variety of unique landforms.
