Ncert-notes / Geography NCERT Notes / Topography or Landforms

Topography or Landforms

  • Topography involves the examination of the Earth's land surface, encompassing features like craters, rivers, valleys, and mountains. In contemporary terms, topography primarily focuses on measuring and documenting elevation contours to generate a three-dimensional representation of the Earth's surface.

Introduction to Landforms:

  • A landform refers to a feature on the Earth's surface shaped by various geomorphic processes (endogenic and exogenic) and agents like rainfall, wind, glaciers, and waves.
  • Each landform possesses distinct physical characteristics, size, and nature. Over time, these landforms may undergo changes due to continuous geomorphic processes and agent activities.
  • The ocean basins and continents are termed landforms of the first order. 
  • Larger features on continents and ocean basins, such as mountains, plains, plateaus, continental shelf, continental slope, and submarine ridges, fall under landforms of the second order.
  • Smaller landforms like a river valley, sand dune, or floodplain are classified as landforms of the third order.
  • Some landforms are categorized as tectonic, while others are volcanic. The topographical features exemplify the interplay between geological factors and external forces acting on the Earth.

Cycle of Erosion

  • The theory of the evolution of landform is known as the geomorphic cycle, sometimes known as the geographic cycle or cycle of erosion.
  • William M Davis first proposed this idea, which postulated that landforms underwent a series of stages, from youth to maturity to old age, with each stage characterized by particular traits.
  • Detachment, transport and deposition are the three main phases of erosion. Raindrops impact the disintegration of soil aggregates, after hydration and the scouring action of surface runoff both can cause soil particles at the soil surface to separate from the bulk of the soil body.
  • During a runoff event, the movement of water and sediment or detached soil particles across the soil surface frequently exhibits discrete patterns that correspond to various forms of water erosion.

Classification of Landforms

Classification of Landforms

Topographies/Landforms

Formed by Internal Factors

Formed by External Factors

By Slow Movement (Diastrophism)

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By Sudden Movement

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By River

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By Groundwater

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By Glaciers

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By Aeolian or Wind

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By Sea Waves

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Landforms Formed by Internal Factors

Formed by External Factors

  • The Earth beneath our feet consists of three layers: the core, mantle, and crust. The crust and upper mantle collectively form the lithosphere.
  • The lithosphere is not a single piece but is broken into several plates known as tectonic plates.
  • These plates are in constant motion, leading to continuous changes. Major alterations in tectonic plates can result in the uplifting or sinking of the lithosphere.
  • Landforms formed by internal factors involve both slow and sudden movements.

By Slow Movement

  • Diastrophic forces arise from the movement of solid material within the Earth's crust. These forces encompass all processes that move, elevate, or build portions of the Earth's crust, falling under the umbrella of diastrophism.
  •  Orogenic processes involve mountain building through severe folding, affecting long and narrow belts of the Earth's crust.
  •  Epeirogenic processes entail the uplift or warping of large parts of the Earth's crust.
  •  Earthquakes involve local, relatively minor movements.
  • Plate tectonics involve horizontal movements of crustal plates.
  • Slow movements can be classified as 
  • Vertical Movements, primarily associated with the formation of continents and plateaus, also known as Epeirogenic movements.
  •  Horizontal Movements act on the Earth's crust from side to side, causing orogenic movements, classified as forces of compression and forces of tension.

By Sudden Movement

  • Lithospheric plate boundaries are susceptible to sudden geomorphic movements.
  • Due to pressure caused by the pushing and pulling of magma in the mantle, plate boundaries become extremely unstable.
  • Some movements cause abrupt changes in the crust. Examples include earthquakes and volcanoes, generating significant deformation in a short period.

Landforms Formed by External Factors

  • External processes influencing landforms result from erosion or deposition.
  • These processes encompass weathering, wind action, surface and groundwater, and sea ice.
  • Forces acting on the Earth's surface due to natural agents like running water, glaciers, wind, and waves are categorized as external processes of landforms.

Landforms Formed by Rivers

  • The impact of running water, particularly rivers, is extensive and surpasses other agents of gradation. Rivers originate in elevated landforms such as mountains, hills, and plateaus, receiving water from various sources like rain, glaciers, springs, and lakes.
  • The primary functions of a river include erosion, transportation, and deposition. 
  • Fluvial landforms are sculpted or built up by the continuous flow of water, comprising two components: sheet flow (overland flow as a sheet) and linear flow (overland flow as streams and rivers).
  • Different stages of landscape development result from the action of water:
    • Youth: Early stages dominated by down-cutting, with broad, flat streams, marshes, swamps, and lakes.
    • Mature: Middle stages where streams cut their beds slower, and lateral erosion of valley sides intensifies.
    • Old: Streams meander freely over vast floodplains, featuring natural levees, ox-bow lakes, etc. Divides remain broad and flat with lakes, swamps, and marshes.

Erosional Landforms of Rivers

Various erosional landforms include:

  • V-shaped Valleys: Deepening of riverbeds due to intense erosion, resulting in distinctive V-shaped valleys.
  • Gorge: A deep valley with steep to straight sides, formed in hard rocks.
  • Canyon: Characterized by steep, step-like side slopes and wider at the top than the bottom, commonly forming in horizontal bedded sedimentary rocks.
  • Waterfalls: Generally found in the upper course of rivers, formed due to erosion, especially in areas with a mix of soft and hard rocks.

Depositional Landforms of Rivers

Depositional landforms include:

  • Alluvial Fans: Formed when streams break into footslope plains, depositing cone-shaped alluvial fans.
  • Delta: Deposits formed at the mouth of rivers, categorized into Arcuate, Bird's Foot, Estuarine, and Cuspate Deltas.
  • Flood Plains: Major landforms resulting from river deposition, with fine-sized materials deposited in slower-moving waters.
  • Natural Levees: Low, linear ridges of coarse deposits along riverbanks, preventing breaches.
  • Meanders The river flowing through holz qed comparatively gentle slopes takes deviation when the sediments or rock forms create obstruction to the flow. The sinuous curves formed along the river course are called meanders. Meander is not a landform but only a type of channel pattern

Ox-Bow Lake:

  • An ox-bow lake is typically a curved lake found in a plain, occupying an abandoned cut-off channel reach.
  • As meanders in rivers grow into deep loops, erosion at the inflection point may lead to the formation of ox-bow lakes.

Landforms Formed by Groundwater:

  • In rocks rich in calcium carbonate like limestones or dolomites, surface water and groundwater, through the chemical processes of solution and precipitation deposition, create various landforms.
  • Karst topography is the term used to describe the typical landforms produced by groundwater action in limestone or dolomite regions.

Erosional Landforms of Groundwater:

  • Sinkholes: Circular openings that are funnel-shaped towards the bottom.
  • Doline: If the bottom of a sinkhole forms the roof of an underground void or cave, it might collapse, leaving a large hole known as a doline or collapse sink.
  • Uvalas: Form when sinkholes and dolines join together, creating long, narrow to wide trenches.
  • Lapies: Irregular limestone surfaces with pits, trenches, grooves, and ridges.
  • Caves or Caverns: Caves are formed by the solution action of groundwater in horizontal bedding planes.
  • Caverns are underground caves with irregular floors, formed by various methods in limestone or chalk areas.
  • Blind Valley: A deep, narrow river valley that abruptly ends in a depression or sinkhole.
  • Hum: A conical residual limestone hill structure found in mature, deeply eroded karst topography.
  • Terra Rossa: A reddish-brown residual soil formed due to water flow inside the land, dominated by iron oxide.

Depositional Landforms of Groundwater:

  • Stalactites: Icicle-shaped formations hanging from the ceiling of a cave with varying diameters, broad at their bases and tapering towards the free ends.
  • Stalagmites: Stalagmites rise from the cave floor, forming due to water dripping from the surface or through the thin pipe of the stalactite immediately below it.
  • These formations can take the shape of columns, discs with a smooth, rounded bulging end, or a miniature crater-like depression.
  • Pillars:Stalagmites and stalactites eventually merge, giving rise to columns and pillars of varying diameters.

Landforms Formed by Glaciers:

  • Glaciers, masses of ice moving as sheets over the land or linear flows down mountain slopes in trough-like valleys, are driven by gravity.
  • Glacial erosion is substantial due to friction caused by the sheer weight of the ice.

Erosional Landforms of Glaciers:

  • Cirque: Found at the heads of glacial valleys, cirques are deep troughs or basins with steep concave to vertically dropping high walls.
  • Cirque lakes, tarns, or corrie lakes form when water accumulates in cirques and glaciers disappear.
  • Arete: A knife-edge ridge formed when two neighboring corries run back to back, separating two adjacent glaciers
  • Nunatak: Summits or ridges of mountains surrounded by flowing glacial ice, with heights exceeding 1000 feet in Antarctica.
  • Roche Moutonnee: A resistant residual rock hummock with a surface striated by ice movement. The upstream side is smoothed by abrasion, while the downstream side is roughened by plucking, found in both highland and lowland glaciated regions.

Depositional Landforms by Glaciers

  • Some of depositional landforms by glaciers are as Drum ins Drumbrae an it with ed mound,
  • largely composed of glacial drift with some images of grave and sued The sons of drums
  • Facing the glacier is called tend coss it is blunter and steeper than the other end called tail.

  • Eskers: Sinuous ridges of coarse gravel representing meltwater deposits flowing subglacial. Eskers can reach lengths of up to 100 km and heights of 100 m.
  • Outwash Plain: A glacial plain deposited at or beyond the ice margin, typically forming fan-shaped, valley bottom, or plain deposits.
  • Moraines: Landforms directly deposited by a glacier or ice sheet. Moraines are often composed of partly stratified material.

Landforms Formed by Aeolian Processes (Wind Action):

  • Wind, a significant erosion and deposition agent, constantly transports dust, sand, and ash.
  • Responsible for forming expansive 'seas of sand' in regions like Arabia, Sahara, Australia, Thar, Gobi, etc.

Erosional and Depositional Landforms:

  • Mushroom Rocks: Sand blasting by winds carves the surface of rocks, forming pillar-like structures known as rock pedestals. Further erosion at the base creates mushroom rocks in desert or arid areas.
  • Zeugen: Ridge and furrow landscapes resulting from mechanical weathering and abrasion by wind action. When soft rock layers are sandwiched between hard rock layers, wind erodes the soft rock faster, forming the characteristic zeugen structure.
  • Yardang When soft and hard rocks are arranged vertically instead of horizontally like in zeugen, unequal erosion makes corridor-like structure separated by steep-sided over, having ridges of hard rocks formed, called yardang. These are used by caravans in deserts and commonly found in the Atacama desert.

  • Inselberg: Isolated residual hills rising abruptly from level ground, composed of highly resistant granite rocks. Surrounding low-lying eroded areas are termed pediments or pediplains, shaped by wind erosion.
  • Deflation Hollows: Erosional landforms created by wind action, where deflation hollows can lead to the formation of oases or swamps in desert regions.
  • Playa: Shallow, circular lakes formed by deposition in the middle of desert basins, filled with rainwater and transforming into lakes. Saline playas may be known by various names such as salt flats, salt marshes, saladas, salars, salt pans, alkali flats, or salinas.
  • Pediment: A gently sloping surface resulting from erosion, often found in desert areas at the base of a mountain or as a plain without an associated mountain.
  • Dunes: Depositional landforms shaped by wind action, prevalent in Erg deserts. Dunes are deposited perpendicular (transverse) to the prevailing wind direction.
  • Transverse dunes : The dunes deposited perpendicular (transverse) to the prevailing wind direction
  • Star Dunes: Feature a high central peak extending three or more arms.
  • Barchan: Crescent-shaped dunes oriented transversely to the wind, with a convex and gentle windward side and a concave and steep leeward side.
  • Seifs: Longitudinal dunes forming parallel to the wind direction, characterized by a gentle windward slope and a steep leeward side. Commonly found in trade-wind deserts like the Sahara, Australian, Libyan, South African, and Thar deserts.
  • Loess: Fertile, yellowish fine dust blown beyond the desert limits and deposited on neighboring lands. May form badland topography when streams cut deep valleys.
  • Dreikanter: Pebbles shaped by wind-blown sand, transforming into 3-facet stones known as ventifacts.
  • Stone Lattice: Net-like rock structures formed by wind erosion in deserts, where speedy winds erode soft parts, leaving behind hard sections, resembling a net.
  • Demoiselles: Rock pillars with resistant rocks at the top and softer rocks below.
  • Archs: Result from erosional processes like hydraulic action and abrasion, where waves hitting sea caves hollow them out. As the cave expands and breaks through the headland, an arch is formed.

Landforms Shaped by Sea Waves:

Sea Waves: Formed by wind transferring energy through friction on the sea surface. Larger waves are generated by faster, prolonged, and uninterrupted wind.

Sea Wave-Crafted Landforms:

  • Cliffs: Resulting from dominant shore erosion processes, cliffs are steep formations along the shoreline ranging from a few meters to over 30 meters in height.
  • Wave-Cut Cliffs and Terraces: Two common forms shaped by erosion along the shore, showcasing the varied sizes and shapes of sea waves.
  • Sea Caves: Formed by the relentless lashing of waves against cliff bases, creating hollows that widen and deepen over time.
  • Sea Stacks: As cave roofs collapse and sea cliffs retreat, isolated rock remnants stand as sea stacks just off the shore. These resilient rock masses were originally part of cliffs or hills.
  • Beaches: Characteristic of deposition-dominated shorelines, beaches may also appear in patches along rugged shores. Sediments comprising beaches often originate from land, transported by streams, rivers, or wave erosion.
  • Sand Dunes: Positioned just behind the beach, sands lifted and winnowed from beach surfaces accumulate to form sand dunes.

  • Bar A ridge of sand and shingle formed in the sea in the off-shore zone lying approximately parallel to the coast is called an off-shore bar.
  • Barrier Bar An off-shore bar which is exposed due to further addition of sand is termed a barrier bar. The off-shore bars and barriers commonly form across the mouth of a river or at the entrance of a bay.
  • Spits Sometimes such barrier bars get keyed up to one end of the bay when they are called spits
  • Spits and Headlands: Spits may also develop attached to headlands.
  • Lagoon Formation: Barriers, bars, and spits at the bay's mouth can lead to the gradual development of a lagoon. Over time, sediment from the land or the beach fills the lagoon, transforming it into a broad coastal plain.

Types of Coastal Landforms:

  • Fjord: Formed in areas where glaciation extended below the current sea level. As glaciers retreat, U-shaped valleys get filled by the sea, creating narrow and steep coastlines.
  • Dalmatian Coast: Arises from rising sea levels or land subsidence, causing the sea to invade low-lying areas. Examples are found on the East shores of the Adriatic Sea in Southern Croatia.
  • Ria Coast: Formed by the submergence of river valleys, with the depth increasing seawards and shallower coasts compared to the adjoining sea.
  • Haifa Coast: Resulting from the submergence of low coastal land in seawater. This coast lacks fragmentation and valleys, exemplified by Haifa city and its associated landforms in Israel.
  • Emerged Highland Coast: Characterized by a straight coastline with steep cliffs and deeper offshore waters. Features like spits, lagoons, and beaches are common, as seen in the Kathiawar coast in Gujarat.

Agents of Landforms

Erosional Landform

Depositional Landform

Running Water

V-Shaped Valley

Alluvial Fans, Delta, Natural Levees

Ground Water

Lapies, Sinkholes, Dohae, Uvalas

Stalactite, Stalagmite, Pillars

Glaciers

U-Shaped Valley, Waterfall, Cirque

Drumlin, Esker, Moraines, Horn

Wind

Mushroom Rock, Zeugen, Yardang, Inselberg, Dreikanter

Playa, Pediment, Sand Dunes, Barchans, Loess

Waves

Cliff, Caves, Arch, Stack

Beach, Bars, Lagoons

Prelims Facts

  • Which theory explains the formation of mountains, sea floor spreading and origin of earthquakes?
    • Theory of plate tectonics (WBCS (Pre) 2015)
  • Continents have drifted apart because of Tectonic activities (BPSC (Pre) 2011
  • What is the proof that Deccan was part of Gondwana land?
    • -Similarity in the common sequence of layers of rock IMPPSC (Pre) 2009)
  • Many island arcs and peripheral trenches of the Pacific ocean are the result of
    • The Convergence of two oceanic plates (MPPSC (Pre) 2011)
  • The curved shape of Himalayas to the South is due to
    • - Maximum push offered at two ends of the Indian Peninsula during its Northward drift (MPPSC (Pre) 2014]
  •  Which processes helps in the formation of Rift valley
    • Faulting (APSC (Pre) 2015]
  •  The process of folding is the result of
    • - Orogenetic force [BPSC (Pre) 2011
  •  Landform produced by erosional work of wind in desert areas is known as
    • -Inselberg (MPPSC (Pre) 2015)
  •  Exfoliation is which type of weathering?
    • -Physical (MPSC (Pre) 2014)
  • Till, moraine and boulder clay are depositional landforms due to
    • Glacial activity [APPSC (Pre) 2017
  • The word "Bergschrund' is associated with The work of Glaciers [APSC (Pre) 2013
  • Which type of landform is formed by Glacier 7
    • -Glacial Landforms (MPPSC (Pre) 2011
  • Ural mountain, Aravalli mountain and Appalachian mountain are part of Old folded mountain [UKPSC (Pre) 2016]
  • Sierra Nevada, Himalaya and Alps are part of which type of mountain?
    • - Young folded mountain (MPPSC (Pre) 2022
  • What is responsible for 'V'shaped valley gorges and waterfall relief features?
    • -River (MPSC (Pre) 2012
  • Which landforms are produced by a river in its upper course?
    • -Gorge, Rapids and Waterfall (MPSC (Pre) 2013]
  • Where are the Yardangs found?
    • Deserts (MPSC (Pre) 2012]
  • Plain formed due to filling up of lakes are called
    • -Lacustrine Plains [JPSC (Pre) 2013]
  • Which action creates 'Mushroom rocks' which are usually found in
    • Deserts [APSC (Pre) 2015]
  • Which landform is associated with flood plains, along the banks of large rivers?
    • Natural Levees [MPPCS (Pre) 2023]
  • Which landform is formed when most of the limestone is taken away by pits and trenches ?
    • Lapies [MPPCS (Pre) 2023

Self Check

  1. When some forces cause two rock surfaces to come together, causing mechanical wearing or grinding of their surfaces is called

(a) Erosion

(b) Abrasion

(c) Attritionalth

(d) Denudation

2. Arete, Cirque, Flood planes etc., are the landforms associated with which of the Following?

(a) Glacial activity

(b) Fluvial activity

(c) Volcanic activity

(d) Erosion activity

3. Which of the following is responsible for 'V'- shaped valleys, gorges and waterfall relief features?

(a) River

(b) Glacier

(c) Sea waves

(d) Underground water

4. Arrange the following features formed by rivers in its course starting from upstream.

  1. Meanders
  2. Falls
  3. Deltas
  4. Ox-bow lakes

Select the correct answer by using the codes given below.

(a) 2, 1, 3 and 4

(b) 2, 1, 4 and 3

(c) 1, 2, 3 and 4

(d) 1, 4, 2 and 3

5. Stalactites and stalagmites are features of

(a) glacial topography

(b) volcanic topography

(c) karst topography

(d) fluvial topography

6. Which of the following landforms is formed by glaciers? MPPSC (Pre) 2011

(a) Tarn

(b) Lagoon

(c) Lappies

(d) Doline

7. Glaciated regions are associated with

(a) 'V'-shaped valley

(b) 'U'-shaped valley

(c) sand dunes

(d) stalactites

8. Match List I with List II and select the correct answer by using the codes given below the lists.

List I (Landform Features)

List II (Locations)

A. Alluvial Fans

1. Mountainous areas

B. V-shaped Valleys

2. Coasts

C. Deltas

3. Lower reaches of the river

D. Ox-bow Lakes

4. Mountain foothills

Codes

(a) 4 1 2 3

(b) 4213

(c) 3 214

(d) 3 124

9. Which of the following statements are concerned with eskers and drumlins?

  1. Eskers are ridges of crudely bedded gravels and Sands.
  2. Drumlins are constituted mostly of boulders and clay.
  3. Basket of eggs topography is the characteristic of terrains with eskers
  4. While eskers are built by glacier streams, drumlins result from glacier action.

Choose the correct answer from the option given below.

(a) 1, 2 and 3

(b) 1, 2 and 4

(c) 3 and 4b

(d) 1 and 2

10. Where are the Yardangs found? MPSC (Pre) 2012

(a) Oceans

(b) Desert

(c) Wetlands

(d) Snowfields

11. Which among the following pairs are correct?

Number

Landforms

Topography

1.

Cirque and Col

Glacial topography

2.

Barkhans and Yardangs

Desert topography

3.

Eddies and Potholes

Fluvial topography

 

Select the correct answer by using the codes given

(a) 1, 2 and 3

(b) 1 and 2

(e) 2 and 3

(d) 1 and 3

12. Match List I with List II and select the correct answer by using the codes given below the lists.

List I (Geomorphic agents)

List II (Features)

1. Ground water

A. Plunge pool

2. Running water 

B. Horns

3.. Glacier

C. Playas

4.  Wind

D. Lapies

Codes

(a) 4123

(c) 3124

(b) 3214

(d) 4213

13. Which of the following pairs are correctly matched?

Region

Denudation Agent

Features

1. Glaciers and snow

Temperate latitude

2. Waves

Coastlines

3. Temperature

Deserts

Select the correct answer from the following codes.

(a) Only 1

(b) 1 and 2

(c) 2 and 3

(d) All of these

14. Which of the following influences the formation of deltas?

  1. Tides
  2. Currents
  3. Waves
  4. Rate of sedimentation

Select the correct answer from the following codes.

(a) 1 and 4

(c) 1, 3 and 4

(b) 1 and 3

(d) All of these

15. Consider the following statements.

  1. The main work of river is deposition.()
  2. Deltas do not obstruct the river flow.

Select the correct answer from the following codes. 

(a) Only 1

(b) Only 2

(c) Both 1 and 2

(d) Neither 1 nor 

Know Right Answer

1 (b)

2 (d)

3 (a)

4 (b)

5 (c)

6 (a)

7 (b)

8 (a)

9 (b)

10 (b)

11 (a)

12 (b)

13 (b)

14 (d)

15 (a)

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