Geography UPSC NCERT Notes: Glacial Erosional Landforms

Glacial Erosional Landforms are an interesting formation of nature. In terms of the UPSC Civil service exam glacial erosion landforms are an important topic for exam preparation. In these NCERT Geography notes for UPSC we will be covering topics like cirque, Horns and Serrated Ridges and more. Not only is this an important chapter for UPSC exams, but erosional landforms is an important study note for other competitive exams too such as  SSC, State Civil Services and more. Therefore, Testbook has prepared a set of NCERT glacial erosional landforms notes for your benefit.

Glacial Erosional Landforms (UPSC Geography Notes): Download PDF Here!

Glacial Landforms Definition

• Glaciers are masses of ice, which are moving as sheets over the land or in linear movement stepping down the slopes of mountains through valleys. These glaciers are spread over the plains at the foot of mountains. 
• The movement of glaciers is not similar to rivers. As their movement could be a few centimeters to a few meters in a day or may be less than that also. 
• Gravitational force works behind the movement of glaciers. 
• Glaciers cause tremendous erosion because of friction force which is caused by the sheer weight of the ice.
• Sometimes glaciers cause damage to un-weathered rocks, reducing them into low hills and plains. 
• Glaciers also lead to creation of various landforms which may be classified into erosional and depositional landforms.
• India’s largest glaciers are present in the Karakoram range, viz Siachen (72 km), while Gangotri in Uttar Pradesh (Himalayas) is 25.5 km long.

Know more about Geography NCERT Notes on Continental Drift here. 

Types of Glaciers

Glaciers are of many types, they are:

• Continental Glaciers: These glaciers are found in the Antarctic and in Greenland. 
• Ice Caps: These glaciers are covered with snow and ice on mountains from which the valley, mountain glaciers originate. 
• Piedmont glaciers: These glaciers form a continuous sheet of ice at the base of the mountain as in Southern Alaska. 
• Valley glaciers: These glaciers are also known as Alpine glaciers and majorly found in higher regions of the Himalayas in India and in other countries also they are present at high mountain ranges. 

Also learn about Highest Mountain Ranges in India

Glacial Erosional Landform 

Cirque

• It is known to be the most common landform in glaciated mountains. 
• They are mainly seen at the heads of glacial valleys. 
• The accumulated ice cut these cirques while they move downward towards the top of the mountain. 
• They are mainly deep, long and wide troughs or basins which have steep concaves that vertically drop high walls at its head as well as sides.
• After the disappearance of glaciers a lake full of water is mainly seen within the cirques. Such lakes are called cirques or tarn lakes. 
• Cirque can be two or more than two i.e. one leading into the next below it in a stepped sequence. 

Learn more about Geography NCERT Notes on Biological Weathering here. 

Horn and Serrated Ridges

• They are formed through headward erosion of the cirque walls.
• When three or more radiating glaciers cut headward upto when their cirques meet, high,
• sharp pointed and steep sided peaks called horns form. 
• The space present between Cirque side walls or headwalls get narrow due to progressive erosion and turn into serrated which is referred as aretes with sharp crest and zig-zag outline. 

Glacial Valleys or Troughs

• These valleys are trough-like and U-shaped having broad floors and relatively smooth and steep sides. 
• These glacial valleys contain littered debris or debris shaped as moraines which have swampy appearance. 
• There are few lakes also which have mainly jumped out of rocky floors or formed by debris within the valleys along with  hanging valleys at an elevation on one or both sides of the main glacial valley.
• Glacial valleys are formed when smaller tributaries are not able to cut as deeply as bigger ones and remain ‘hanging’ at higher levels than the main valley as discordant tributaries.
• A valley formation occurs by carvation of a small tributary glacier that joins with a valley carved out by a much larger glacier.
• Glacial troughs with large depthness are filled with sea water and making up shorelines are called fjords/fjords. 

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Glacial Depositional Landforms

Outwash Plain 

• When glaciers reach their lowest point and then melt, leaving behind stratified deposition material having rock debris, clay, sand gravel, etc, such a layered surface is called outwash plain or an outwash plain.

Esker 

• They resemble features of an embankment and are often used for making roads. 
• They are formed from the un-assorted depositions of rock, gravel, clay etc. running along a glacier in a till plain.

Kame Terraces 

• Kame Terraces are formed when a meltwater stream deposits its sediments between the ice mass and the valley wall.
• It is a stratified geomorphological feature which is formed from the deposition action of glacier meltwater, an irregularly shaped hill or mound composed of sand, etc. 

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Glacial Cycle of Erosion

Youth 

• In this stage of glacial erosion cycle there occurs the inward cutting activity of ice in a cirque.
• In the stage Aretes and horns are at an emerging state whereas hanging valleys are not prominent at this stage.

Maturity 

• In the stage there occurs the emergence of hanging valleys. 
• The opposite cirques start coming closer and the glacial trough acquires a stepped profile which is regular and graded.

Old Age 

• The emergence of a U-shaped valley marks the start of this stage. 
• Prominent development in this stage is of outwash plains with features such as eskers, kame terraces, drumlins, kettle holes etc. 

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