A landform is any natural feature of the area of land which has been created either by erosion or by deposition due to various agents such as wind, river, and sea waves.

Erosional Landforms Due to Action of Wind

Pediplains: These are the geographical structures/ landforms which have been created when the high relief structures in the desert areas have been reduced to low relief areas due to the action of wind.

Deflation Hollows: Deflation refers to the removal of top layer / loose particles from the surface due to the blowing action of wind. When this removal results in the formation of shallow depressions on the surface due to the consistent blowing action of wind, the landform created is known as Deflation Hollows.

Mushroom Tables: Mushroom tables are the ventifacts that have been given the shape of mushrooms. Ventifacts are referred to as the rocks that have been polished or abraded due to the wind-driven particles / loose particles of sand that hit the rocks. These are typically found in arid areas where there might be very little to no vegetation with strong winds.

Erosional Landforms Due to Action of Rivers

River valley: The valleys are usually V-shaped that have been carved out by the flowing river and the carrying away of the sand particles from the surface, but the shape of the valley may differ from the original shape that has been carved out due to the varying speed of the flowing water at various levels.

The two sides of the V-shaped valleys are always in touch which is caused due to the increased rate of down–cutting known as Valley – deepening / Vertical erosion. The valleys have been classified into two types:

• Gorges
• Canyon

Potholes: Potholes are small depressions usually of the cylindrical shape which have been made on the bed of the river valleys. These potholes are formed generally on rocky/coarse-grained areas.

Potholes are formed due to the potholing or the drilling mechanism of the river water. In such a mechanism (potholing), eddies are formed in the river water which then starts to rotate in a circular manner and drills out the materials of the surface creating potholes.

River Terraces: River terraces are the narrow flat surfaces that have formed on either side of the river valleys. In some cases, the river terraces are formed in multilayers on either sides which when arranged/viewed simultaneously might be considered as Steps.

Peneplains: Peneplains are referred to as low relief undulating plains which have been formed due to protracted erosion.

Ox – Bow Lakes: Ox – bow lakes are U – shaped lakes that have been formed due to cutting off a wide meander of a river which results in formation of free standing of a body of water. It is formed due to the eroding bank of the rivers.

The ox – bow term can also be referred to as a U – shaped bend in a river, whether or not there are any cuts in the mainstream of rivers.

Erosional Landforms Due to Actions of Sea Waves

Cliffs: Cliffs are referred to as vertical coasts raised above the seawater. The steepness of the cliffs depends on the rate of erosion caused due to the sea waves. The sea waves hit the lower areas of the cliffs resulting in the erosion of the lower surfaces.

If the marine erosion of the cliff exceeds the rate of weathering of the cliff due to subaerial agents, it results in the formation of a very steep cliff.

The beginning of the formation of the cliff is marked by the erosion of the coastal rocks by the hydraulic mechanisms or the abrasion of the lighter rocks by the high-speed waves.

Sea Caves: Sea caves are created/formed along with the coastal areas of the seas due to the gradual removal of the loosely packed particles by the upstream waves. These are then widened into larger cavities in the areas which are again enlarged due to the gradual erosion action of the waves and forming coastal caves.

Sea Arches: When a certain portion of the coast has extended to a considerable distance, the sea waves that are working from the opposite direction resulting in the cutting of a passage through the soft rocks. The beginning of the sea arches is marked by narrow small holes in the soft rocks which are then enlarged into bigger holes called Sea Arches.

Sea Stacks: Sea stacks are formed when the roof of the sea arches collapses either due to eroding action by any of the agents / due to its own weight. When the roof collapses, the solitary mass of rocks that joined the arch standing in the river is known as Sea Stacks. Small stacks that stand underwater are termed STUMPS.

Erosional Landforms Due to Actions of Ice/ Glaciers

Cirque: When the snow is collected at the upper end in the shape of a bowl, it is known as a cirque.

Eskers: These are the ridges that have been formed due to the deposition of the sand/ gravels due to the melting ice which flows through the tunnels and even under the glaciers.

Drumlins: Drumlins are termed as the elongated, teardrop shaped hills of rocks, and sand which has been formed under the moving ice of glaciers. These can be long enough upto 1.2 miles (~ 2 kilometres).

FAQs

Question. What are erosional landforms?

Question. What are the major types of erosional landforms?

Question. What is the role of water in the formation of erosional landforms?

Question. How do glaciers contribute to erosional landforms?

Question. What are desert erosional landforms?

MCQs

1. Which of the following is an example of a glacial erosional landform?

A) Canyon

B) U-shaped valley

C) Sand dune

D) Meander

2. What is a primary characteristic of desert erosional landforms?

A) Formed by water erosion

B) Created by wind erosion

C) Formed by glacial action

D) Shaped by volcanic activity

3. What is an example of a fluvial erosional landform?

A) Sea cliff

B) Meander

C) Sand dune

D) Pediment

4. Which erosional landform is typically created by the action of waves along the coastline?

A) Sand dune

B) Sea stack

C) U-shaped valley

D) Pediment

5. How are gorges formed?

A) By the wind’s erosional action

B) Through the rapid flow of water cutting through rock layers

C) By glacial plucking and abrasion

D) By the deposition of sediments

GS Mains Questions and Model Answer

Q1: Discuss the formation of erosional landforms by rivers and their impact on the surrounding landscape.

Answer: Rivers shape erosional landforms like V-shaped valleys, gorges, and meanders through processes like abrasion and hydraulic action. These features influence water flow, sediment distribution, and ecological balance, playing a crucial role in agriculture and regional geography.

Q2: How does glacial erosion differ from river erosion in shaping landforms?

Answer: Glacial erosion involves ice movement, creating U-shaped valleys, cirques, and fjords through plucking and abrasion. River erosion relies on flowing water, forming V-shaped valleys, gorges, and meanders. Glaciers reshape landscapes on a larger scale compared to rivers.

Q3: What role do wind and water play in shaping desert landforms, and how does this differ from glacial processes?

Answer: Wind forms desert features like sand dunes and yardangs through deflation and abrasion, while water erosion in deserts forms canyons during flash floods. Glaciers create larger-scale erosional features like U-shaped valleys through ice movement and plucking.

Previous Year Questions on Erosional Landforms

1. UPSC CSE 2021

Question: Examine the role of glaciers in the formation of erosional landforms.

Answer: Glaciers shape erosional landforms like U-shaped valleys, cirques, and fjords through plucking and abrasion. Their movement carves massive features, impacting mountain topography and altering regional ecosystems.

2. UPSC CSE 2020

Question: Describe the different types of erosional landforms created by rivers and their impact on the surrounding environment.

Answer: Rivers form landforms like gorges, waterfalls, and meanders through erosion. These features influence regional ecosystems, sediment distribution, and water availability, playing a crucial role in agriculture and hydrology.