As glaciers move across the landscape, they erode it and deposit sediment, as well as shaping it with plucking and abrasion.
Basal ice at the bottom of glaciers has a rough, sandy texture similar to that found on sandpaper. When scraped over rocks, the abrasion caused by this rough surface leaves scratches or striations in their surfaces – leaving behind scratches (striations marks) for miles down below.
Glacial melting and movement has the power to change the land in numerous ways, leaving its surface exposed. Glacial erosion encompasses two primary processes: plucking and abrasion.
Plucking occurs when glaciers freeze around lumps of rock in their ice, which then break off and are carried along by the glacier’s movement. It is especially prevalent in regions with deep crevasses in the ice surface.
As glaciers move across mountains, they erode landforms such as hanging valleys, cirques, aretes, and horns, leaving behind an array of different landforms such as hanging valleys.
Studies have demonstrated that researchers can accurately ascertain the direction a glacier moved by measuring linear features such as striae on boulders and limestone surfaces, such as measuring their orientation relative to one another. Results revealed that most temperate glaciers’ linear features revealed an eastward flow direction, suggesting that basal sliding was likely their dominant mechanism of movement.
Glacial erosion occurs when rock is worn away by glacier ice. There are different methods glacial erosion can occur, but one such as abrasion is particularly notable. A glacier moving downhill scrapes over bedrock similar to how sandpaper would, leading to massive amounts of erosion which leaves grooves called striations marks on it’s path causing massive amounts of bedrock destruction and grooves on it – creating more erosion over time and leaving grooves known as striations marks in its path striations grooves form underfoot causing even further erosion over time.
Plucking. As glaciers move over a landscape, they pick up bits of rock and deposit them elsewhere, creating aretes or pyramidal peaks as a result of glacial erosion. Other landforms formed include cirques, troughs, rock basins and moraines.
Some scientists believe these processes are the main contributors to why glaciers carve out landscapes as they move along, but other factors need to be taken into account as well. Abrasive forces could also play a part, as could hydraulic pressure from melting water and temperature fluctuations within glacial cavities causing rocks to shatter apart.
Glaciers scraping over landscapes erode it and carry off any loose material, creating landforms such as corries, aretes, pyramidal peaks and ribbon lakes in their wake.
Freeze-thaw weathering is another significant contributor to glacial erosion. This occurs when water from melting snow seeps into cracks in rocks, freezes and expands, creating further fractures, which ultimately rip apart rocks forming crevasses or fractures, eventually dismantling entire rock faces. Freeze-thaw weathering also shapes landforms such as scree slopes and blockfields.
Glacial erosion primarily shapes landscapes by way of two main processes: abrasion and plucking. Abrasion occurs when rocks frozen to the bottom and sides of a glacier rub against bedrock beneath them like sandpaper, creating visible scratches known as striations marks in the bedrock beneath them. Plucking occurs when glaciers temporarily melt around larger boulders before freezing again again, ripping them from their foundations before transporting them along.
Glacial erosion transforms landscapes, producing amazing landforms. From lakes to mountains, glaciers can sculpt landscapes in numerous ways through plucking, abrasion and freeze-thaw weathering processes that leave unique landforms at every scale from meters or decametric scale to kilometric scale like cirques, rock drumlins and fjords.
Glaciers are adept at dislodging sediment from valley sides. Erosion rates for basins containing glaciers tend to be greater than in those without them; their movement erodes bedrock.
Glaciers possess incredible erosional power near their termini, as subglacial melt water exacerbates basal sliding and sediment evacuation – making it easier for glaciers to scour bedrock, create debris flows and deposit erosion products as glacial till.