As glaciers progress across a landscape, they erode rocks and sediments around them, producing beautiful landforms like ribbon lakes and cirque stairways. Furthermore, this erosion transforms V-shaped valleys created by streams into U-shaped ones resulting in small rocks being scattered throughout their bottom.
Glacial erosion occurs through physical processes of abrasion and plucking. In this article we’ll investigate these processes and their effect on unique landforms.
Abrasion
Glacial erosion occurs through various means, but one method is abrasion. This occurs when glacier ice rubs up against rock beneath it and scratching away at it particle by particle, gradually wearing away at its surface until eventually leaving behind fine-grained material known as “rock flour” that erodes downstream through glacial streams or lakes (see image), giving glacial lakes their characteristic milk-white hue and giving U-shaped valleys, horns and moraines characteristic features associated with glaciation: U-shaped valleys, horns and moraines among many other features associated with glaciation: U-shaped valleys, horns and moraines all result from glacial erosion: Abrasion makes an important contribution towards landscape features associated with glaciation such as U-shaped valleys, horns and moraines as it wears away material from rock surfaces left behind from scratching against them, scratching away particles that wears away part by part from under their own weight: worn away pieceme by particle; eventually leaving behind rock flour from which runs downstream to eventually form fine-grained material that becomes carried downstream in glacial streams (see image). Rock flour gives glacial lakes their distinctive milk-white color that comes downstream in glacial streams (see image) leaving behind. Abrasion plays an integral part in many landscape features associated with glaciation: U-shaped valleys horns a moraine due to glaciation: all have formed by glaciation: these landscape features. Abrasion causes many landscape features associated with glaciation: U shaped valleys horns from which stream carry downstream that travels downstream carrying away in glacial streams which then flows downstream forming lakes with milk-white hued glaciation also leaves its characteristic dilute milk-white color due to carried downstream streams then carry off by carrying off-flow off streams carrying out dust covered surface in its own characteristic dilute milk-white color too. horns moraine. Abrasion contributes created due to glaciation such as U-shaped valleys moraine as well as landscape features like U- horns etc abrasion also play out due to glaciation such as U horns carrying glaciation including their milk white hue due to glaciation as they carry streams carry rock flour on streams carrying glacial streams being carried downstream carrying downstream as carry rocks from downstream further. as -white color as rock flour carrying glacial lakes dilute milk-white glacial streams carried downstream carrying away sedimentation as their distinctive milk-white lakes having dilute milk white.
Abrasion is an integral process, but only under certain conditions. First, glaciers with sliding bases – known as glaciers with basal slip – experience erosion more frequently. Cold-based glaciers remain attached to bedrock, and thus do not undergo erosion as quickly. Abrupt warming of slow moving glaciers enables melt water accessing new subglacial bedrock zones and thus increase erosion rates that exceed even their long-term rates of erosion.
Plucking
Glaciers often must exert extra effort when they reach rocks that are harder for them to erode, leaving behind grooves called glacial striae on rocks that show where the ice scraped the surface of them below.
Glaciers create these grooves when they move over bedrock in a valley or mountainside, abrading it while leaving unaffected sections unabraded – taking away only rough or blocky sections that irritate it (known as lee sides).
Glaciers can create stunning landforms. When glaciers erode a mountainside in this way, it can leave behind a bowl-shaped valley known as a cirque; when two glaciers flow down opposite sides of a mountain peak they may create sharp-sided horns called aretes; furthermore they may form hillocks known as roche moutonees which consist of chunks of bedrock with one smooth, streamline-molded side and an uneven, rough lee side – the former leaving an arete behind.
Freeze-thaw weathering
Glaciated landscapes feature different kinds of rock that erode in different ways. Sandpaper-like rocks such as silica sand are easily eroded while concrete requires much greater effort. As glaciers move across these surfaces, they sculpt them into landforms known as troughs and ribbon lakes – depressions filled with water when melting glaciers retreat; or small depressions carved by them into mountain sides then dammed by an end moraine damming system.
Freeze-thaw weathering occurs when there are cracks in a rock’s surface and water seeping into those cracks freezes to form cracks, expanding and exerting pressure against it, breaking pieces off. When this process thaws out further, further fragmentation occurs causing pieces of rock to come off further than originally anticipated; this type of weathering is common in cold climates and could explain why some rocks have smooth surfaces while others don’t.
Moraine
Glaciers are powerful rivers of ice that shape the environment as they move across it, altering landforms in their path through erosion processes such as ribbon lakes, kames and mountain crests as they go. Furthermore, glaciers leave behind some fascinating glacial features such as corries and aretes to add visual interest and character.
Moraine is any accumulation of unconsolidated glacier sediments and debris carried along by moving glaciers, such as sand, gravel, rocks or clay that is left behind on its journey. Moraines may also be known by other names, including till.
As glaciers traverse across landscapes, they erode rocks by means of abrasion and plucking, as well as freeze-thaw weathering and freeze-thaw thawing. Erosion processes may vary depending on the type of rock in its path as well as environmental considerations; soft rocks will typically be more affected than harder ones – which explains why continental glaciated regions tend to feature more landforms due to glacial activity than alpine ones. Also important are size and speed considerations which affect how much they will erode landscape.