Glacial Landforms: Glacial landforms are landforms that are produced by glaciers. The migration of massive ice sheets throughout the Quaternary glaciations is responsible for most of the current glacial landforms. In areas where there are no active glaciers or glaciation processes at the moment, glacial landforms can still be found.
A straight row of stakes placed across a glacier will gradually assume a curved shape as they descend the valley, demonstrating that the glacier moves more quickly in the middle than at the edges.
What is a Glacier?
A glacier is a sizable and huge ice mass that travels slowly across land. Typically, glaciers take on the form of a tongue, being wider at the source and getting smaller as they descend. Despite not being a liquid, a glacier moves gently under the constant pressure of snow that has accumulated above. The middle, where there are few obstacles, has the fastest rate of movement. The friction caused by the valley sides and valley floors prevent the sides and bottom from moving forward. 97.2% of the water on Earth is in the oceans and inland seas, compared to 2.1% in glaciers.
Glacial Landforms Formation
In locations where more snow accumulates each year than melts, glaciers start to form. The snow starts to compress right away when it falls, or it gets denser and more densely packed. Firnification is the process through which snow condenses into glacial firn (thick, granular ice). The firn grains combine into a massive mass of solid ice when the ice gets thick enough, which takes around 50 metres (160 feet). The glacier starts to calve as a result of its weight. A glacier’s many components move at various rates. The glacier’s centre, flowing ice, advances more quickly than its base.
Landforms by Glaciers
Glaciations typically result in depositional features in the lowlands and erosional features in the highlands. It uses two techniques to erode its valley: plucking and abrasion.
Plucking: Glaciers pull out individual blocks and drag them away by freezing the joints and beds of underlying rocks.
Glacier abrasion: The debris that is frozen into it causes the glacier to scratch, scrape, polish, and scour the valley floor.
There are mainly two types of glacial landforms: Depositional and Erosional
Glacial Landforms Depositional
Landscapes in mid- and high-latitude alpine regions have been significantly shaped by glaciers. The main glacial depositional landforms include
- Glacial Till
These flat, oval-shaped topographies resemble ridges and are largely made of glacial till together with significant amounts of gravel and sand. It develops as a result of the glacier’s cracks allowing rock debris to fall underneath heavily weighted ice. Drumlins’ long axes go parallel to the direction in which the ice is moving. The movement of the glaciers is shown by drumlins. The steeper of the two ends, the Stoss end is utilised to face the ice flow.
One of the most spectacular landforms created by fluvioglacial deposits is the esker. They are often made of gravel and cleaned sand. The size and shape of the eskers vary. Water seeps down around the borders of glaciers or flows on top of the ice when it melts. These waters collect beneath the glacier and run in a channel beneath the ice-like streams. These streams have ice-formed banks and flow above the ground. When the ice melts, very coarse materials, such as stones and blocks, combined with a few small fragments of rock debris, settle down in the valley of ice beneath the glacier and are then visible as the twisting ridge known as Esker.
Glacial till is the unsorted coarse and fine detritus that meltwater glaciers release. There is some quantity of rock debris that is washed down and deposited that is tiny enough to be carried by such melt-water streams. Outwash deposits are a type of glaciofluvial deposit. The outwash sediments are diverse and fairly stratified.
They are extensive ridges of glacial till deposits. Long ridges of debris called terminal moraines are left by glaciers at their toes. Along the sides parallel to the glacial troughs, lateral moraines develop. Ground moraines are the uneven sheets of till that many retreating valley glaciers leave on their valley bottoms.
The medial moraine, which is surrounded by lateral moraines, is located in the glacier valley’s middle.
In comparison to lateral moraines, they are not completely formed. There are times when medial moraines and ground moraines cannot be distinguished.
Glacial Landforms Depositional Diagram
Here is the diagram for Glacial Depositional Landforms
Glacial Landforms Erosional
The main glacial erosional landforms include
- Glacial Valleys/Troughs
- Aretes and Horns
A cirque has an amphitheatre-like shape. Cirques are depressions in the form of bowls created by glacial activity. The down valley is faced by the hollow end of a cirque. The headwall, or rear wall, of the cirque landform, is made up of a curved or bow-shaped cliff. Most of the time, the headwall curves backwards in the cirques that are cut into plateaus with flat tops. Otherwise, the headwalls are shaped angularly as a result of height inconsistencies along a cirque landform’s perimeters.
Cirques frequently have shallow basins that lead to lakes at their bases. Signs of significant glacial erosion and plucking can be seen by closely inspecting a cirque’s shallow basin and the headwall of an adjacent cirque.
2. Glacial Valleys/Troughs
Valleys with meltwater streams are not like valley glaciers. The glacial ice washes away the eroded material from the headwalls and sidewalls of the glaciated valleys in the stream valleys. However, compared to streams, the glaciers cover a far wider region of the valleys’ cross-section. As a result, unlike glaciers that erode the valley bottoms, meltwater streams damage a narrower area of valleys.
Typically, meltwater streams sculpt V-shaped valleys by eroding strips of rock near valley bottoms. The loose material from the base and sidewalls is cleared as the glaciers interact with the V-shaped valleys.
Additionally, glaciers erode the valley bottoms and sidewalls, even more, creating U-shaped valleys. Flatter bases and steeper sides define the U-shaped valleys.
3. Aretes and Horns
Aretes, which are glacial landforms, are frequently located between two circles that are perpendicular to one another. These U-shaped valleys’ U-shaped valleys were eroded by glaciers, leaving behind knife-edged hills. The glaciers further erode the bedrock beneath these valleys, resulting in aretes at the higher reaches of the parallel valleys. There is frequently a low area, known as a col, between aretes between two cirques.
Several cirques are frequently grouped radially on the flanks of larger mountain ranges, such as the Alps. A sharp peak is created when the higher portions of these mountain ranges are worn by glaciers. These pointed peaks, known as horns, are bordered by sheer headwall cliffs that are split by aretes.
Glacial Landforms Erosional Diagram
Here is the diagram for Glacial Erosional Landforms
Glacial Landforms Significance
Rivers are fed by glaciers: Perennial Rivers are dependent on glaciers. The Ganga River originates from the Gangotri Glacier, one of the biggest glaciers in the Himalayan Mountains. In Bangladesh and India, the Ganges is the primary source of both freshwater and power.
Acts as reservoir: Three-quarters of the freshwater on Earth is kept in glaciers as reservoirs. As a result, glacier ice is both the largest freshwater reservoir and the second-largest water reservoir on Earth. Additionally, glacial runoff has an impact on downstream water temperatures.
For aquatic life: In mountainous areas, many aquatic species need cold water temperatures to survive, which glaciers supply. Some aquatic insects can’t exist without the cooling effects of glacial meltwater because they are so sensitive to stream temperature. Native trout and other keystone salmon species may be negatively impacted by these alterations to the stream ecosystem.
People and Glaciers: Glaciers offer numerous beneficial resources to people. Crops can be grown on fertile soil thanks to glacial till. Concrete and asphalt are made from sand and gravel deposits.
Glacial Landforms UPSC
A glacier is a sizable, long-lasting mass of crystalline ice, snow, rock, sediment, and water that forms on land and slides down a slope due to gravity and its weight. They are delicate climate change indicators. 97.2% of the water on Earth is in the oceans and inland seas, compared to 2.1% in glaciers.
There are various kinds of glaciers, and throughout their existence, they produce both erosive and deposited landforms. You can use the many glacial depositional landforms mentioned in this article to prepare for the UPSC Exam.
Glacial Landforms FAQs
Q) What is a glacier?
Ans. A glacier is a sizable and huge mass of ice that moves slowly.
Q) What is a periglacial landform?
Ans. Periglacial landforms are a result of severe frost action, frequently in conjunction with permafrost.
Q) What is a Glaciofluvial landform?
Ans. Landforms known as glaciofluvial landforms are the result of glacier meltwater movement. They can develop beneath, on top of, in front of, or along the edges of past glaciers and can be erosional or depositional landforms.
Q) How are glacial mountains formed?
Ans. Snowfalls occur frequently and increase each year without fully melting from mountain glaciers. Two elements are needed to have this accumulation of snow, which eventually turns into glacial ice: chilly summers and a lot of snow in the winter.
Q) How much water do glaciers hold?
Ans. About 2.1% of all of Earth’s water is frozen in glaciers.
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