Glacial erosion sculpts our mountainous landscape. This process creates unique features like U-shaped valleys, hanging valleys, cirques, and horns; as well as creating landforms such as moraines, stratified drift, drumlins, and varves.
Glacial erosion is typically caused by two processes; abrasion and plucking. Both erode rocks by scraping and gouging it away.
What is Erosion?
Glacial erosion is an incredible force that has the ability to transform landscapes, altering their contours in significant ways. The movement of ice has the power to alter our world with powerful changes, leaving unique landforms such as cirques, aretes, pyramidal peaks and U-shaped valleys among other landforms created. Glacial erosion also plays a part in shaping moraines and stratified drift into moraines or carving striations into rock.
Glaciers typically erode by plucking rocks from the ground surface, then transporting them along their course. Plucking also contributes to another important process called abrasion; glaciers scrape away at underlying rock by scraping against themselves with plucked rocks from above, leaving behind scratches known as glacial striations patterns in its path.
Erosion rates at glacier bases depend on its mass, temperature and basal sliding resistance; warmer glaciers tend to experience greater erosion rates than colder ones; in areas with active tectonics erosion rates can also be higher than elsewhere.
Types of Erosion
Glacial erosion is an extremely powerful geomorphic process. Therefore, understanding how glaciers erode is vitally important so we can predict their actions in our landscapes.
Glacial erosion takes various forms. One such process, called plucking, occurs when glacial ice rubs against bedrock and removes pieces by scraping, creating interesting landforms like roches moutonnees and crag and tails in its wake.
Erosion occurs when melting snow/ice has the power to push its way through rocks and deposit its debris, creating different depositional landforms such as moraines, eskers, kames or drumlins.
Last, glacial erosion occurs when ice erodes bedrock beneath it, producing depositional and erosional landforms like stoss-and-lee topography, glacial drift and stratified drift as well as nunatuks, kames and ridges. This section explores its effect on landforms by looking at glacial erosion as a mechanism, with particular reference to basal sliding mechanisms and glacier thermal regime.
Landforms of Erosion
As the glaciers recede, their erosion leaves behind distinctive landforms called glacial landforms. These may include lakes and peaks as well as ridges, mounds, valleys and even caves; created through processes like abrasion, plucking and freeze-thaw weathering.
Abrasion is the primary form of glacier erosion. Ice scraping along the surface of a rock face erodes it away, creating erosional scars on its face.
Plucking erosion refers to when ice picks up rocks from nearby and transports them further downstream, often when flowing over more resistant terrain than other rocks. This type of erosion often happens during glacier flows over rocks with greater resistance against erosion than others.
Glacier erosion of mountains has left behind various landforms, such as cirques, aretes, ribbon lakes, truncated spurs and hanging valleys. Cirques are bowl-shaped amphitheater-like depressions created when glaciers erode mountains; similarly they can flow through V-shaped valleys formed by rivers before further eroding them further.
Glacial erosion is a powerful geomorphic process, capable of altering landscapes dramatically. Understanding its dynamics is critical in linking it with climate changes and their associated environmental consequences.
Glaciers erode rock by means of abrasion and quarrying. Furthermore, they sculpt its surface using frost wedging, glacial plucking and striations; creating some of the most dramatic landscapes such as bowl-shaped cirques (such as those found in Glacier National Park), high altitude lakes known as tarns, sharply-angled aretes and sharpened landforms known as drumlins moraine piles and roche moutonnes as a result of glacial erosion. Its rate depends heavily on climate factors like basal sliding speed and meltwater supply; creating stunning landscapes such as those seen throughout Glacier National Park!