Glacial erosion transforms the landscape around glaciers through processes of plucking and abrasion, producing unique landforms such as lakes, horns, rock basins, and moraine.
A river will erode landscapes as it flows, but glaciers erode differently; in this article, we will investigate these differences and how they occur.
Freeze-thaw weathering (also referred to as frost-shattering) is a type of glacial erosion found in cold climates. It happens when water that has infiltrated cracks and fissures freezes during the day before expanding and thawing at night, weakening cohesion between mineral grains in rocks, eventually breaking them apart to produce crevices, talus slopes and boulder fields of loose, angular fragments.
The sediments created from glacial erosion contribute to soil development, ecosystem processes and geologists reconstructing Earth history. Furthermore, they provide microhabitats for flora and fauna who flourish within these unique conditions – testament to glacial erosion’s power.
Glaciers can be powerful forces of nature, creating landforms through erosion. As they move along their journey they scrape against rocks and sediment that come in their path, breaking apart what remains into pieces that are then carried along on the glacier’s journey.
Hitchhiking rocks and sediment typically range in size from small particles to larger boulders, leading to glacially abraded surfaces bearing many types of “tool marks”, from microscopic scratches to deep gouges over several metres long.
Glaciers’ ability to collect rocks and sediment contributes to the great lakes’ size; Lake Winnipeg in Canada in particular has seen rapid glacial advances over time due to this effect. Glaciers also plow through sediment with ease, producing fluting effects known as fluting on their edges.
Glaciers can have a dramatic impact on the landscape. Their influence comes through erosion processes like plucking and abrasion, shaping it in unexpected ways.
Glacier ice contains bits of rock, sediment, and debris which have a rough, sandy texture. As they float downhill, glaciers drag these “clasts” over bedrock surfaces where they grind them away to leave scratches called striations scars on its surface.
These scratches help form various landforms, including U-shaped valleys, horns and moraine. Furthermore, their scratches affect erosion rates in cirque and trough canyons, playing an integral part in geohazards associated with glaciers’ cliffs and slopes; their presence also plays a part in ribbon lakes formed when multiple glaciers carve valleys into mountain sides simultaneously.
When rivers encounter hilly or mountainous terrain, their course often curves around resistant rocks to avoid them and their edges create interlocking spurs that create interlocking spurs.
These ridge-like features are created through a combination of plucking and abrasion. Although glaciated landscapes tend to experience this process more frequently, similar conditions exist wherever erosion and landform shaping take place.
Glacial plucking occurs when a glacier travels over harder-to-erode rocks than their surroundings, leading to rock fragments being worn away by abrasion and eventually breaking apart entirely over time; eventually this process results in what is known as truncated spur formation.
glaciers typically erode landscapes through abrasion and plucking, but there are other processes at work too. If certain rocks are harder than their surrounding ones to erode, they may stick out from valley bottoms and be “picked up” by glaciers – creating truncated spurs and hanging valleys; ribbon lakes may form too; these long thin finger lakes typically found in glacial troughs are another outcome.
Other features formed by glacial erosion include aretes, corries, rock lips and pyramidal peaks; ribbon lakes form in hollows between truncated spurs near glacial termini; moraines, eskers and kames are other depositional features created by glacial erosion; while glacial striations is the scratch left by moving ice on rocks as it grinds them against each other.