Landforms | ICSE Class 6 Geography Notes

This note covers landforms, internal and external processes, young and old fold mountains, block and volcanic mountains, rift valleys, plateaus, plains, world distribution, and the influence of landforms on people's occupations, settlements and culture.

What are landforms and how can we recognise them?

Landforms are natural physical features of the Earth's surface. Mountains, plateaus and plains are three broad categories. A valley is a lower area between hills or mountains, often containing a river or stream. These features give different places their distinctive appearance.

To recognise a landform, observe its height, slopes and upper surface. A slope is an inclined surface. The summit is the top of a mountain. A high feature with steep slopes and a narrow summit differs from raised land with a broad, relatively flat surface.

How are height and shape different?

Altitude means height above sea level. Sea level is the average level of the ocean surface. Altitude tells us how high a place is, while shape tells us whether it has a narrow summit, a broad surface or gently rolling ground.

Undulating means gently rising and falling. A plain need not be perfectly level. A plateau, similarly, need not have an absolutely flat top. Its raised position and more or less flat surface should be considered together.

The drawing shows mountains in the background, two with snow-covered tops, a plateau on the left and a plain in front. A river winds from the mountains towards the foreground, where fields and houses are drawn.

See Fig. 3.1 in your NCERT textbook

The drawing brings several landforms together in one landscape. It helps connect the river's mountain setting with lower land farther along its course. Landforms are therefore best understood both separately and as parts of a connected landscape.

How do internal and external processes shape the land?

Endogenous processes, also called endogenic processes, originate within the Earth. Exogenous processes, also called exogenic processes, act at its surface. Both help explain why landforms develop and change. Internal movements can build mountains, while external processes wear away and redistribute material.

The crust is the Earth's outermost solid layer. Movements within the Earth can bend or break rocks and raise or lower areas of land. Internal changes include slow movements as well as sudden events such as volcanic eruptions, which release material through openings in the crust, and earthquakes, which are vibrations of the Earth's surface.

What happens to rocks at the surface?

Weathering is the breaking up of rocks at the Earth's surface. Erosion is the wearing away of the landscape by agents such as water, wind and ice. An agent here means something that carries out the work of changing the landscape.

Transportation is the carrying away of eroded material. Deposition is its laying down elsewhere. Weathering, erosion, transportation and deposition are related, but they are not interchangeable terms. Breaking a rock and carrying its fragments away describe different parts of the process.

1. Rocks at the surface break up through weathering.
2. Moving water, wind or ice wears away material through erosion.
3. The moving agent transports the loosened material to another place.
4. The material is deposited, contributing to the development of new surface features.

A glacier is a moving mass of ice. Rivers and glaciers can erode the landscape, while rivers also deposit material on plains. Mountain building and erosion can continue together, as they do in the Himalayas. A landscape is not necessarily finished once a mountain has formed.

How do fold mountains form and how do young and old ranges differ?

Folding is the bending of rock layers under pressure. When forces push towards each other, rock layers may bend rather than break. Large-scale folding and uplift, meaning upward movement of land, help produce fold mountains. Their formation is an internal process.

A mountain range is a connected group or chain of mountains. Picture layers being squeezed from opposite sides. Their bends help explain the word folding. This is a simplified explanation of a large process inside the Earth, not a suggestion that a mountain range forms as quickly as a classroom model.

What does young mean for a mountain?

Young fold mountains are relatively young in the Earth's history. The Himalayas have tall, sharp peaks, but even their relatively recent formation extends back millions of years. Young does not mean that people watched an entire mountain range appear during recent human history.

Old fold mountains have been exposed to wearing down over a much longer period. The Aravalli Range has shorter, more rounded mountains and hills shaped by erosion. Its present appearance is therefore different from the tall, sharp peaks of the Himalayas.

The names identify the ranges to study; their locations add the spatial part of the topic. The Himalayas are in Asia, the Alps in Europe and the Andes in South America. Compare a range's location with its formation and appearance instead of learning these as unrelated facts.

How do faulting and block mountains differ from folding?

Faulting occurs when rocks fracture and move relative to each other along the break. A fault is a fracture along which movement has occurred. In folding, layers bend; in faulting, rock blocks become displaced. The distinction concerns the process, not simply the final height.

Block mountains form when fault movements leave a block standing higher than neighbouring land. The higher block may rise, or neighbouring blocks may move down. The essential feature is the difference in level created by movement along faults.

How can a simple model show this?

Draw adjacent blocks with breaks between them. In one sketch, show a block standing above its neighbours and label it block mountain. In another, show a central block lowered between two faults and label it rift valley. Label the breaks faults.

The model shows relative positions. It should not show folded layers as the explanation for the raised block. Nor should it show a river carving out the lowered block: that would replace the faulting process with a different process.

The Black Forest, Vosges and Vindhyas are the block-mountain examples to identify. Locate the Black Forest in Germany, the Vosges in France and the Vindhyas in India. Connect each name with the idea of movement along breaks in rocks.

Block mountains and rift valleys can therefore be studied together. One draws attention to relatively high land, the other to a relatively lowered strip. Explaining the movement is more useful than describing both merely as uneven ground.

How are volcanic mountains built?

A volcano is an opening in the Earth's crust through which molten material erupts. Molten means melted. Molten rock below the surface is called magma; when it reaches the surface, it is called lava. The opening is also called a vent.

Volcanic mountains develop through the accumulation of erupted material. Lava cools and becomes solid, while ash and other erupted material can also accumulate. Repeated additions build up the land around the opening. This is different from bending existing rock layers into folds.

What sequence explains their formation?

1. Molten material below the surface moves towards an opening in the crust.
2. An eruption brings lava and other volcanic material to the surface.
3. Lava cools and solidifies, while erupted material accumulates around the opening.
4. Repeated accumulation can build a volcanic mountain.

Mount Kilimanjaro in Africa and Mount Fujiyama in Japan are examples. Kilimanjaro is in eastern Africa and is an isolated mountain, rather than part of a mountain range.

Most of the world's mountains occur in ranges, but the word most matters. Kilimanjaro provides an example of an isolated mountain. Its position and origin help distinguish it from a range such as the Himalayas without implying that every mountain belongs to a chain.

What are valleys and how does a rift valley form?

A valley is a lower area between hills or mountains, often with a river or stream flowing through it. The word often matters: a definition of a valley does not require a river to be present in every example.

A rift valley is a long, relatively narrow depression formed when a block of land is lowered between faults. A depression is an area lower than its surroundings. The process is linked to movement within the Earth rather than simply to the wearing action of water.

How is a rift valley different from a river-eroded valley?

A river-eroded valley develops as running water wears away the land. A rift valley begins with fault movements and the relative lowering of land. A river may later flow through a rift valley, but the river's presence does not prove that erosion created the original depression.

1. Forces within the Earth produce fractures in the rocks.
2. Movement occurs along the faults.
3. A strip of land becomes lower than the blocks beside it.
4. The resulting depression forms a rift valley, which may contain a river.

The Rhine, Narmada and Nile are the rift-valley examples to locate. The Rhine is in Europe, the Narmada in India and the Nile in Africa. Learn the names with the formation process and their map positions.

Valleys also matter for people. In mountain regions, regular farming can only be practised in some valleys because much of the surrounding terrain is steep and rough. Terrain means land considered in terms of its physical features, such as slopes, heights and surface form.

How do plateaus form and what types can we identify?

A plateau rises above the surrounding land and has a more or less flat surface. Some of its sides are often steep slopes. A plateau is therefore different from a mountain with a narrow summit and from an extensive low plain.

Plateaus can be young or old in the Earth's history. Their heights range from a few hundred metres to several thousand metres. A plateau's broad surface does not mean that it must be close to sea level or easy to cultivate.

How can plateaus be grouped by formation?

A tectonic plateau forms through movements that raise a large area of the crust. Tectonic means connected with movements and deformation of the Earth's crust. A volcanic plateau, also called a lava plateau, develops where successive lava flows spread, cool and build up a broad raised surface.

A dissected plateau is a plateau cut into by rivers and erosion, leaving valleys across the raised land. Dissected means cut into parts. This term describes later modification of a plateau, whereas tectonic and volcanic describe ways in which raised land can originate.

The Deccan Plateau in central and south India is one of the world's oldest plateaus and was formed through volcanic activity millions of years ago. The Tibetan Plateau is the world's largest and highest plateau. The East African plateaus extend through Kenya, Tanzania and Uganda.

These examples show why formation, height and surface appearance should be considered separately. A broad raised surface can have a volcanic origin and later be altered by erosion. The word plateau identifies the landform, while additional terms explain its origin or modification.

What does a Case study of plateaus reveal about resources and relief?

Mineral deposits are natural concentrations of minerals in the Earth; minerals are naturally occurring substances that make up rocks. Plateaus are rich in these deposits, and mining, the extraction of minerals from the Earth, is a major activity on them.

The East African Plateau is famous for gold and diamond mining. India's Chhota Nagpur Plateau has huge reserves of iron, coal and manganese. These examples connect the rocks beneath a landscape with the work people undertake there.

Does every plateau have poor farming conditions?

Many plateaus have rocky soil and are less fertile than plains, making farming less favourable. Lava plateaus are an exception because they often have rich black soil. Fertile means able to support good plant growth. Many and often should remain part of these comparisons.

Plateaus also have waterfalls, where a river drops steeply to a lower level. The Nohkalikai Falls descend from the Cherrapunji Plateau in Meghalaya. A waterfall's drop measures a change in height; it is different from the altitude of the plateau itself.

The Tibetan Plateau's great average altitude explains its name, the Roof of the World. Its length measures something entirely different. Distinguishing altitude, horizontal extent and waterfall drop prevents unlike measurements from being treated as though they all represented the same feature.

How are plains formed and what types are there?

Plains are extensive flat or gently undulating areas without large hills or deep valleys. They are generally not more than 300 metres above sea level. The word generally makes this a broad description, rather than a rule that every plain must satisfy.

How does deposition build a floodplain?

Sediments are particles such as rock fragments, sand and silt carried by water or other agents. Silt is fine earth material. Rivers collect sediments, transport them and deposit them on lower land. A floodplain is flat land built up through river deposits during flooding.

1. A river erodes and collects material as it flows through the landscape.
2. The river carries particles of rock, sand and silt downstream.
3. When it overflows its banks, water spreads over neighbouring land.
4. Layers of fine soil and other sediments are deposited, building a flat, fertile floodplain.

Plains can be grouped by formation. Depositional plains are built from accumulated material. Erosional plains result from the wearing down of higher land. Structural plains develop where Earth movements expose or raise broad areas of comparatively level rock layers.

Floodplains belong to the depositional group. The Gangetic plain of India and plains of North America are important regions to locate. On a world map, the Mississippi plain provides a named North American example. Connect this location with the broad, relatively level character of plains.

This comparison separates a general description of a landform from a measurement for one named summit. It does not define every mountain by Everest's height, just as the general description of plains must not be turned into an exceptionless boundary.

What does a Case study of the Gangetic plain show about people's lives?

The Gangetic plain, also called the Ganga plain, supports agriculture and river fishing. Rivers bring water and deposit sediments that make the soil fertile. This combination helps explain why farming is a major occupation and why plains support a large part of the world's population.

Food crops grown here include rice, wheat, maize, barley and millets. Fibre crops include cotton, jute and hemp. A fibre crop is grown for fibres used to make materials such as cloth or rope, rather than primarily for food.

How do water and transport create opportunities and challenges?

Traditional agriculture has been mostly rainfed, meaning watered through rainfall. Irrigation means supplying water to fields, for example through canals or by pumping groundwater. Groundwater is water below the ground. Irrigation has increased agricultural production but has also contributed to groundwater depletion, meaning a decrease in its supply.

Other problems affecting the Ganga plains include high population and pollution. Productive land and accessible water create opportunities, but resources still need care. The benefits of irrigation should therefore be discussed together with its contribution to declining groundwater.

River navigation means travelling or transporting goods by river. The gentle slope of plains makes river navigation easy and supports economic activities. People used rivers extensively for travel in earlier times, and boats remain a preferred form of movement along some stretches of the Ganga.

Thousands of years ago, the first civilisations developed around rivers in fertile plains. A civilisation is a complex society with organised settlements and social life. This link between river plains and early settlements shows how geography helped shape history, as well as present-day occupations.

How does life in mountains compare with life in plains?

Mountain terrain is usually rugged, meaning rough, and has steep slopes. Regular farming can only be practised in some valleys. Terrace farming adapts slopes for cultivation by cutting them into steps. In many mountainous regions, herding, meaning keeping and tending groups of animals, is preferred to agriculture.

Mountains also offer tourism opportunities. Their scenery and fresh air attract visitors, and activities include hiking, skiing, mountaineering and paragliding. Tourism is often an important source of income, but excessive visitor numbers can put the fragile environment under pressure.

Why are mountains important beyond their slopes?

Some mountains carry snow, depending on their height. At lower altitudes, snow melts every summer and feeds rivers. At high altitudes it may never melt. Water from mountain regions therefore connects mountain landscapes with people and environments farther downstream.

Mountain slopes are often covered by montane forest, meaning forest growing in mountainous regions. Such forests, together with mountain rivers, lakes and grasslands, support varied wildlife. Mountains also have cultural value: people have travelled to holy sites there for many centuries.

The comparison identifies opportunities and constraints, not a single lifestyle followed by everyone. People adapt to different landforms. Geography influences occupations and culture, while each region still contains different communities, activities and ways of living.

Where are the important landforms on the world map?

Distribution means the places across which a feature occurs. Learning landform distribution involves linking a name, a type and a location. Begin with continents, then identify the country or region where needed. This makes a list of names into a geographical pattern.

The map uses orange for mountain ranges, brown for plateaus and green for river plains. It labels the Rocky range, Andes, Atlas, Ural and Himalaya, together with the Tibetan and East African plateaus and the Mississippi and Ganga-Brahmaputra plains. It is marked not to scale.

See Fig. 3.8 in your NCERT textbook

Which regions should be connected with mountain names?

The Urals lie along part of the boundary between Europe and Asia. Mount Fujiyama belongs in Japan. The East African plateaus should be associated with Kenya, Tanzania and Uganda. The type of feature matters as much as its name: a plateau must not be labelled as a mountain range.

A map key explains what symbols and colours mean. Include one beside a map so that each kind of landform can be identified.

On an outline map of India, label the Himalayas in the north, the Aravalis in the northwest, the Vindhyas in central India, the Narmada valley, the Deccan Plateau in central and south India, and the Gangetic plain south of the Himalayas. Use distinct symbols for ranges, plateaus and plains, and explain each in a key.

Check each label against its geographical position and landform type. A river plain, a river and a mountain range are related features, but a label should identify the particular feature being studied.

Glossary

• Landform — A natural physical feature of the Earth's surface, such as a mountain, plateau or plain.
• Altitude — The height of a place or object above the average level of the ocean surface.
• Endogenous processes — Processes originating within the Earth that can raise, lower, bend or break areas of land.
• Exogenous processes — Processes acting at the Earth's surface, including erosion, transportation and deposition by moving agents.
• Weathering — The breaking up of rocks at the Earth's surface, distinct from carrying the material away.
• Erosion — The wearing away of the landscape by agents such as moving water, wind and ice.
• Deposition — The laying down of material previously transported by water, wind, ice or another moving agent.
• Folding — The bending of rock layers under pressure, contributing to the formation of fold mountains.
• Faulting — Fracturing of rocks accompanied by relative movement of blocks along the breaks.
• Rift valley — A long depression formed when a strip of land is relatively lowered between faults.
• Volcanic mountain — A mountain built through the accumulation of lava and other erupted material at the surface.
• Plateau — Raised land with a more or less flat surface and some sides often forming steep slopes.
• Floodplain — Flat, fertile land built from sediments that a river deposits when it overflows its banks.
• Terrace farming — Cultivation on mountain slopes that have been cut into steps to provide farming surfaces.
• Irrigation — Supplying water to fields through methods such as canals or pumping from groundwater.

Common errors and misconceptions

• Misconception: Every high landform is a mountain. Correct: A plateau can be very high while retaining a more or less flat upper surface.
• Misconception: Young mountains formed recently in human history. Correct: Young is relative to Earth's history and can still refer to formation millions of years ago.
• Misconception: Folding and faulting mean the same thing. Correct: Folding bends layers; faulting involves fractures and relative movement along them.
• Misconception: A river flowing in a rift valley must have created it. Correct: Fault movements create the rift depression; a river may subsequently occupy it.
• Misconception: Every plateau has poor soil. Correct: Many plateaus have rocky soils, but lava plateaus often have rich black soil.
• Misconception: Plains must be perfectly flat and below a fixed height. Correct: They can be gently undulating and are generally not more than 300 metres above sea level.
• Misconception: No cultivation is possible in mountains. Correct: Some valleys support regular farming, and terrace farming allows cultivation on stepped slopes.
• Misconception: More tourism brings benefits without costs. Correct: Tourism often provides mountain incomes, but excessive visitor numbers can strain the fragile environment.

Exam-style questions with model answers

Q1. Rocks bend under pressure in one mountain-forming process. In another, rocks fracture and blocks move along the breaks. Name and distinguish the two processes. [2 marks]

1. Folding is the bending of rock layers under pressure, as described in the first process.
2. Faulting involves fractures and relative movement along the breaks, as described in the second process.

Q2. The Himalayas have tall, sharp peaks and are relatively young in Earth's history. The much older Aravallis have shorter, rounded hills shaped by erosion. Compare their age and shape, and explain the change in the older range. [3 marks]

1. The Himalayas are relatively young, whereas the Aravallis are much older. The comparison concerns their place in Earth's history.
2. The Himalayan example has tall, sharp peaks, while the Aravalli example has shorter and more rounded hills.
3. Erosion has worn down and rounded the older Aravallis, explaining the connection between the stated process and their present appearance.

Q3. A river erodes rock, carries sand and silt downstream, overflows its banks, and leaves layers of fine material on neighbouring land. Explain the formation of a floodplain in four points. [4 marks]

1. The river erodes rocks and other surface material, providing the particles that will later help build the plain.
2. Flowing water transports sand, silt and other eroded material downstream as part of the river's sediment load.
3. When the river overflows its banks, water spreads across the neighbouring land rather than remaining within the channel.
4. Fine material is deposited in layers on that land, gradually forming the flat, fertile surface called a floodplain.

Q4. Forces produce faults, and a central strip of land becomes lower than the blocks beside it. A river later flows through the depression. Identify the landform, explain its origin and state why the river does not establish an erosional origin. [3 marks]

1. The lowered strip is a rift valley, a depression lying between faults and relatively higher neighbouring blocks.
2. Its origin is fault movement: the central land becomes lower relative to the land on either side.
3. The river arrives later in the description. Its presence therefore does not show that river erosion produced the original depression.

Q5. Magma is molten rock below the surface; lava is molten rock that reaches it. Material erupts through a vent, cools and accumulates, with repeated eruptions adding more. Explain volcanic mountain formation in four points. [4 marks]

1. Magma is the molten rock below the Earth's surface that supplies material for the volcanic process described.
2. The material reaches the surface through a vent, or opening. Molten rock at the surface is called lava.
3. Lava cools and becomes solid, while erupted material accumulates around the opening rather than being formed by folding.
4. Repeated eruptions add further material, and this accumulation can build up a volcanic mountain around the vent.

Q6. Mountain terrain is usually rugged, regular farming is possible in some valleys, and steps cut into slopes support terrace farming. Herding is preferred in many mountainous regions. Tourism often supplies income, but excessive visitors can strain the environment. Explain six links between this landscape and people's lives. [6 marks]

1. Usually rugged terrain and steep slopes limit the space suitable for regular farming across the wider mountain landscape.
2. Some valleys provide places where regular farming can be practised, so mountain agriculture is not entirely absent.
3. Cutting slopes into steps provides surfaces for terrace farming, showing how people adapt cultivation to the land.
4. Herding is preferred to agriculture in many mountainous regions, giving people an occupation suited to those settings.
5. Tourism often supplies income for mountain communities and therefore creates an economic opportunity alongside farming and herding.
6. Excessive visitor numbers can put pressure on the fragile environment, so tourism can bring a challenge as well as income.

Q7. The Ganga plain has fertile river sediments, agriculture and fishing, and gently sloping rivers used for transport. Irrigation has increased production but contributed to groundwater depletion. High population and pollution are further problems. Explain three opportunities and two challenges using these facts. [5 marks]

1. Fertile sediments create an agricultural opportunity because the river deposits help provide soil in which crops can grow well.
2. River fishing gives people another occupation, connecting access to the river with an economic activity beyond crop cultivation.
3. Gentle slopes make river navigation easy, enabling people to use waterways for movement and other economic activities.
4. Irrigation has increased production, but its contribution to groundwater depletion creates a challenge for maintaining the water supply.
5. High population and pollution place further pressure on the fertile river plain, showing that a productive landscape also faces environmental problems.

Q8. The Tibetan Plateau's average altitude is 4,500 metres and its east-to-west length is nearly 2,500 kilometres. Nohkalikai Falls drop 340 metres from the Cherrapunji Plateau. Identify what each measurement describes without confusing altitude, distance and waterfall drop. [3 marks]

1. The 4,500 metres describes the Tibetan Plateau's average altitude, which is its average height above sea level.
2. The nearly 2,500 kilometres describes its east-to-west horizontal extent. It is a distance across the plateau, not its height.
3. The 340 metres describes the vertical drop of Nohkalikai Falls from the Cherrapunji Plateau, not that plateau's altitude.

Key takeaways

• Landforms are natural surface features; mountains, plateaus and plains differ in height, slopes and the shape of their upper surfaces.
• Internal processes build and displace land, while external processes weather, erode, transport and deposit material across the surface.
• Folding bends rock layers, faulting displaces blocks along fractures, and volcanic activity builds land through erupted material.
• Rift valleys originate through fault movements; a river flowing through one does not establish that erosion created it.
• Plateaus contain important mineral resources; many have rocky soils, but lava plateaus often have rich black soil.
• River deposits build fertile floodplains, while gentle slopes support navigation and connect landforms with occupations.
• Mountain communities adapt through farming in some valleys, terraces, herding and tourism, while excessive tourism can strain fragile environments.
• Learn each named landform with its type, formation and location, and preserve qualifications such as generally, many and often.

Test yourself

What two features distinguish a plateau?

A plateau rises above surrounding land and has a more or less flat surface.

What is the difference between weathering and erosion?

Weathering breaks up rocks at the surface; erosion wears away the landscape through agents such as water, wind and ice.

Which examples connect old and young mountains with different shapes?

The young Himalayas have tall, sharp peaks; the much older Aravallis have shorter, rounded mountains and hills shaped by erosion.

Name the two volcanic mountain examples and their locations.

Mount Kilimanjaro is in eastern Africa, and Mount Fujiyama is in Japan.

Why does a river not necessarily create the valley it flows through?

A rift valley forms through fault movement, and a river may later occupy that existing depression.

What qualification belongs with the usual height of plains?

Plains are generally not more than 300 metres above sea level. Generally prevents this from becoming an absolute limit.

How can mountain slopes be adapted for cultivation?

Steps can be cut into mountain slopes to provide surfaces for terrace farming.

What benefit and challenge are linked to irrigation in the Ganga plain?

Irrigation has increased agricultural production, but it has also contributed to groundwater depletion.