GeographyISC Class 11 · Chapter 8

Aeolian Landforms: Wind Erosion, Erosional Features, Sand Dunes and Loess, ISC Class 11

Updated 15 October 2026 · Fact-checked

Wind shapes hot deserts, where dry loose sand, sparse vegetation and strong winds allow it to erode by deflation, abrasion and attrition. Erosion forms deflation hollows, pedestal rocks, yardangs and desert pavements. Deposition forms sand dunes, such as barchans and longitudinal dunes in the Thar desert, and loess, fine dust laid down far from deserts as in northern China.

What Aeolian Landforms is about

Aeolian (from Aeolus, the Greek god of the winds) processes are the work of wind. They are most effective in hot deserts.

The syllabus covers:
1. Wind erosion: deflation (lifting and blowing away loose particles), abrasion (sandblasting of rock surfaces) and attrition (grains wearing one another down).
2. Ideal conditions for wind erosion in hot deserts: dryness, loose weathered material, sparse vegetation, strong and steady winds, and large daily temperature ranges.
3. Erosional landforms: deflation hollows, pedestal (mushroom) rocks, yardangs and desert pavements.
4. Depositional landforms: sand dunes and their types (barchan, longitudinal or seif, transverse, parabolic, star) and loess.

Examples: the Thar desert of Rajasthan (barchans and longitudinal dunes, shifting dunes), the Qattara Depression (deflation hollow), the Sahara and Arabian deserts, and the loess of northern China.

Weightage: CISCE gives no Class XI unit weightage for ISC Geography. Aeolian Landforms is topic 8 of the Class XI syllabus (Changing Face of the Earth) and can be asked anywhere in the 70-mark Paper I (Theory, 3 hours). Class XI is examined by the school, so your school sets the paper and decides how many marks each topic carries.Source: CISCE ISC Geography (853) syllabus, examination year 2028, Class XI

Key concepts

Processes of wind erosion

1. Deflation: the wind lifts and blows away loose, dry particles of sand, silt and dust from the surface. Over time it lowers the land surface and leaves behind coarser material.
2. Abrasion: wind carrying sand grains acts like a sandblaster, scraping and polishing rock surfaces. Because sand is heavy, it moves mostly close to the ground (generally within a metre or two), so abrasion is strongest near the base of rocks.
3. Attrition: sand grains carried by the wind collide with one another and become smaller, rounder and smoother; desert sand grains are often well rounded and frosted.

Transport by wind: fine dust is carried in suspension, sometimes thousands of kilometres; sand moves by saltation (bouncing) and surface creep (rolling).

Deposition: occurs when wind speed falls or an obstacle (a rock, bush or slope) slows the wind, forming dunes and sand sheets; fine dust settles far away as loess.

Worked example

[4] Explain the three processes of wind erosion. (Recall)

Try it first, then show the solutionSolution

Deflation: lifting and removal of loose dry particles - 1 mark.
Lowers the surface; leaves coarse material - 1 mark.
Abrasion: sand-laden wind scrapes rocks, strongest near the ground - 1 mark.
Attrition: grains collide and become smaller and rounder - 1 mark.

Answer: In deflation, the wind lifts and carries away loose, dry particles, gradually lowering the surface and leaving coarser material behind. In abrasion, wind armed with sand grains scrapes and polishes rocks like a sandblaster, most strongly near the ground. In attrition, the wind-blown grains collide with one another and become smaller, rounder and smoother.

Ideal conditions for wind erosion in hot deserts

1. Aridity: very low and irregular rainfall keeps the surface dry, so particles are not held together by moisture.
2. Loose material: large daily temperature ranges cause rapid physical weathering (block and granular disintegration), producing abundant sand and dust.
3. Sparse vegetation: few plants and roots to bind soil or slow the wind.
4. Strong and steady winds: open, flat surfaces with little friction allow high wind speeds; local heating also creates strong convectional winds and dust storms.
5. Absence of running water most of the time, so wind becomes the main agent of gradation (though occasional sheet floods also shape deserts).
6. Human activity: overgrazing, ploughing of marginal lands and removal of vegetation increase wind erosion and desertification.

These conditions are typical of the trade-wind deserts such as the Sahara, Arabian, Kalahari, Australian and Thar deserts.

Worked example

[4] Why is wind an effective agent of erosion in hot deserts? (Understanding)

Try it first, then show the solutionSolution

Aridity keeps particles dry and loose - 1 mark.
Large daily temperature range produces abundant sand by physical weathering - 1 mark.
Sparse vegetation does not bind soil or slow the wind - 1 mark.
Strong, steady winds over open flat surfaces; little running water - 1 mark.

Answer: In hot deserts very little rain keeps the surface dry and loose; large daily temperature ranges break rocks into abundant sand and dust; there is too little vegetation to bind the soil or slow the wind; and strong, steady winds sweep across open, flat land where running water is rare, so the wind becomes the main agent of erosion.

Erosional landforms

1. Deflation hollows (blow-outs): shallow or large basins formed where deflation removes loose material, often down to the water table, where moist ground stops further lowering and oases may form. The Qattara Depression in Egypt is a very large example, reaching well below sea level.
2. Pedestal (mushroom) rocks: rocks with a narrow base and a broad top. Sand-laden wind abrades the lower part most strongly because sand moves close to the ground, while the upper part is less affected; layers of softer rock at the base speed the undercutting. Common in the Sahara.
3. Yardangs: long, streamlined ridges of rock separated by grooves, aligned parallel to the prevailing wind; they form where bands of hard and soft rock lie parallel to the wind and abrasion scoops out the softer bands. Found in the deserts of Central Asia, Iran and the Sahara.
4. Desert pavement (reg): a surface of closely packed pebbles and gravel left after deflation has removed the fine particles; it protects the ground below from further erosion. Stony deserts of this kind are called reg (Sahara) or gibber plains (Australia); rocky surfaces swept bare of sand are called hamada.

Worked example

[4] Explain the formation of pedestal rocks and desert pavements. (Understanding)

Try it first, then show the solutionSolution

Pedestal rock: sand-laden wind abrades the base most because sand moves near the ground - 1 mark.
Narrow base, broad top; faster with softer basal rock - 1 mark.
Desert pavement: deflation removes fine particles - 1 mark.
Leaves closely packed pebbles (reg) that protect the surface - 1 mark.

Answer: Pedestal rocks form because sand carried by the wind moves mostly close to the ground, so abrasion undercuts the base of a rock more than its top, leaving a narrow stem and a broad cap, especially where softer rock lies below. A desert pavement forms when deflation blows away the fine particles from a mixed surface, leaving a layer of closely packed pebbles (reg) that protects the ground beneath.

Sand dunes and their types

Sand dunes are mounds or ridges of sand deposited by wind where its speed falls, often around an obstacle. A dune has a gentle windward slope, up which sand is pushed, and a steep leeward slope (slip face) down which sand slides. Dunes migrate in the direction of the wind.

Types
1. Barchan: crescent-shaped dune with horns pointing downwind; forms where wind blows from one direction and sand supply is limited on a hard surface. Common in the Thar desert (western Rajasthan) and the Sahara.
2. Longitudinal (seif) dune: long, narrow ridges parallel to the prevailing wind; form where winds are strong and sand supply is moderate, sometimes with slightly varying wind directions. Found in the Thar, the Sahara and the deserts of Australia and Arabia.
3. Transverse dune: long ridges at right angles to the wind, where sand is plentiful and winds are moderate.
4. Parabolic dune: U-shaped, with horns pointing upwind, anchored by vegetation; common on coasts and semi-arid margins.
5. Star dune: star-shaped, with several arms, formed where winds blow from several directions; very high (Sahara, Arabian Empty Quarter).

Shifting dunes threaten farms, roads and settlements; in the Thar they are stabilised by shelterbelts and planting of grasses and trees.

Worked example

[4] Distinguish between barchans and longitudinal (seif) dunes. (Analysis)

Try it first, then show the solutionSolution

Barchan: crescent-shaped; horns point downwind - 1 mark.
Barchan: one-directional wind, limited sand, hard surface - 1 mark.
Seif: long ridges parallel to the wind - 1 mark.
Seif: strong winds, moderate sand; both in the Thar and Sahara - 1 mark.

Answer: Barchans are crescent-shaped dunes whose horns point downwind; they form where the wind blows steadily from one direction and sand is limited on a hard surface. Longitudinal or seif dunes are long, narrow ridges lying parallel to the prevailing wind, formed by strong winds with a moderate sand supply. Both types are found in the Thar and the Sahara.

Loess

Meaning: loess is a deposit of very fine, yellowish, wind-blown dust (silt) laid down in thick layers, often far from its source.

Formation
1. Strong winds lift fine dust from deserts or from glacial outwash plains.
2. The dust is carried in suspension over long distances.
3. Where the wind weakens or rain washes the dust down, it settles and accumulates over thousands of years, sometimes to great thickness.

Characteristics: unstratified, porous, very fine-grained; stands in vertical cliffs when cut by rivers; easily eroded by water into gullies.

Examples

The Loess Plateau of northern China, built of dust blown from the Gobi and other deserts; the Hwang Ho (Yellow River) gets its colour and name from loess.
Loess deposits in the Mississippi valley (USA) and parts of central Europe, derived largely from glacial outwash.

Importance: loess forms very fertile soils supporting intensive farming, but is highly prone to soil erosion; in China people have also dug cave dwellings into loess cliffs.

Worked example

[4] Explain the formation and importance of loess, with examples. (Understanding)

Try it first, then show the solutionSolution

Fine dust lifted from deserts or glacial outwash - 1 mark.
Carried in suspension, deposited far away in thick unstratified layers - 1 mark.
Example: Loess Plateau of northern China (from the Gobi); Mississippi valley - 1 mark.
Very fertile but easily eroded into gullies - 1 mark.

Answer: Loess forms when strong winds lift very fine dust from deserts or glacial outwash plains, carry it in suspension and deposit it far away in thick, unstratified layers, as on the Loess Plateau of northern China, derived from the Gobi, and in the Mississippi valley. Loess makes very fertile soil but is easily eroded into deep gullies.

Aeolian Landforms in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Sandblasting

Suppose workers clean an old stone building by blasting it with sand from a hose; the lower walls they target most become smooth and worn.

Which aeolian process and landform does this resemble?

Try it first, then show the solutionSolution

Sand driven by air scrapes and polishes rock: abrasion.
In deserts, sand travels close to the ground.
Rocks are undercut at the base, forming pedestal rocks.

Answer: It resembles abrasion by wind; because desert sand moves close to the ground, abrasion undercuts rocks at their base, forming mushroom-shaped pedestal rocks.

Memory hook: Low-flying sand, top-heavy rocks.

Dune migration

Imagine a barchan dune 450 m upwind of a village road moves 15 m a year.

How long before it reaches the road, and what can be done?

Try it first, then show the solutionSolution

Time = distance / rate = 450 / 15 = 30 years.
Dunes move downwind as sand slides down the slip face.
Planting grasses, shrubs and shelterbelts can stabilise it.

Answer: About 30 years; the village can stabilise the dune with grasses, shrubs and tree shelterbelts, as is done in the Thar desert.

Memory hook: Plant the dune, save the road.

Desert pavement

Suppose a mixed heap of sand and pebbles is left in a windy courtyard. After weeks, the sand is gone and only a tight layer of pebbles remains on top.

Which desert landform does this model?

Try it first, then show the solutionSolution

Wind removes fine particles: deflation.
Pebbles too heavy to move are left behind.
They form a protective layer: desert pavement (reg).

Answer: It models a desert pavement (reg), formed when deflation removes fine material and leaves a protective layer of pebbles.

Memory hook: Wind takes the dust, leaves the stones.

Topics in this chapter

Aeolian Landforms: key facts

Wind erosion: $D e f l a t i o n + ab r a s i o n + a tt r i t i o n$; Abrasion strongest near the ground.
Conditions: Aridity, loose material, sparse vegetation, strong winds, temperature range; Hot trade-wind deserts.
Erosional landforms: Deflation hollow, pedestal rock, yardang, desert pavement (reg); Qattara Depression; Sahara.
Dune types: Barchan (horns downwind), seif (parallel), transverse (at right angles), parabolic (horns upwind), star; Thar: barchans, longitudinal.
Loess: Fine wind-blown dust, deposited far away; Northern China; Mississippi valley.
Dune migration: $T im e = d i s t an ce / r a t eo f m o v e m e n t$; 450 m at 15 m/yr = 30 years.

How the school exam asks Aeolian Landforms

The question patterns to expect, and the method that works for each.

Question type	How it is asked	Method
Process	Explain deflation, abrasion and attrition; ideal conditions for wind erosion.	Mechanism plus where and why it occurs.
Landform with diagram	Formation of pedestal rocks, yardangs, barchans; types of dunes.	Labelled sketch in words: wind direction, slip face, horns.
Application	Problems of shifting dunes in the Thar; importance of loess.	Cause, effect and remedy with examples.

Tricks to remember Aeolian Landforms

Short memory aids. Say each one aloud once, then use it on a question the same day.

Erosion: 'DAA'
Deflation (lift), Abrasion (blast), Attrition (bump).
Use it when: Three processes.
Barchan horns
Barchan horns point the way the wind goes; parabolic horns point back to where it came from.
Use it when: Dune shapes.
Dune and wind
Seif is Side-by-side (parallel) with wind; Transverse is Troubling the wind (across).
Use it when: Dune orientation.

Aeolian Landforms: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Example 1: Crescent dune · 1 mark · MCQExam level

A crescent-shaped dune with horns pointing downwind is called a:
(a) Seif
(b) Barchan
(c) Parabolic dune
(d) Star dune

Try it first, then show the solutionSolution

Parabolic dunes have horns pointing upwind.
Barchans are crescents with horns downwind.

Answer: (b) Barchan.

Example 2: Assertion-reason: pedestal rocks · 1 mark · Assertion-reasonHarder exam level

Assertion (A): Pedestal rocks are narrower at the base than at the top.
Reason (R): Wind-blown sand moves mostly close to the ground, so abrasion is strongest near the base.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Try it first, then show the solutionSolution

Heavy sand grains travel near the surface.
So the base is undercut, explaining the shape.

Answer: (a) Both A and R are true and R is the correct explanation of A.

Example 3: Yardangs · 4 marks · Short answerHarder exam level

[4] Explain how yardangs form. (Understanding)

Try it first, then show the solutionSolution

Bands of hard and soft rock lie parallel to the prevailing wind.
Sand-laden wind abrades the softer bands faster.
Grooves are scooped out between ridges of harder rock.
Result: streamlined ridges parallel to the wind (Central Asia, Iran, Sahara).

Answer: Yardangs form where bands of hard and soft rock run parallel to the prevailing wind. Sand-laden wind abrades the softer bands faster, scooping out grooves, while the harder bands remain as long, streamlined ridges parallel to the wind, as in the deserts of Central Asia, Iran and the Sahara.

Example 4: Dune shapes and conditions · 4 marks · Short answerHOTS / competency

[4] Why do barchans form in some parts of a desert and star dunes in others? (Analysis)

Try it first, then show the solutionSolution

Dune shape depends on wind direction, wind strength and sand supply.
Barchans: steady wind from one direction; limited sand on a hard surface.
Star dunes: winds from several directions pile sand into central peaks with arms.
So barchans indicate one-directional winds; star dunes multi-directional winds.

Answer: Dune shape depends on wind direction, wind strength and the amount of sand. Barchans form where the wind blows steadily from one direction over a hard surface with limited sand, so sand piles into crescents. Star dunes form where winds blow from several directions, heaping sand into a central peak with radiating arms.

Example 5: Work of wind · 7 marks · Long answerHarder exam level

[7] (a) Explain the ideal conditions for wind erosion in hot deserts and the processes of wind erosion. [4]
(b) Describe three erosional landforms produced by wind. [3] (Understanding)

Try it first, then show the solutionSolution

(a) Aridity, loose material from physical weathering (1).
(a) Sparse vegetation, strong steady winds (1).
(a) Deflation and abrasion (1).
(a) Attrition; transport by suspension and saltation (1).
(b) Deflation hollows (Qattara) (1).
(b) Pedestal rocks (1).
(b) Yardangs or desert pavement (1).

Answer: (a) Hot deserts are very dry, so particles stay loose; large daily temperature ranges break rocks into sand; sparse vegetation leaves the surface unprotected; and strong, steady winds sweep across open land. The wind erodes by deflation, lifting away loose particles, by abrasion, blasting rock with sand, and by attrition, as grains collide and become rounded, carrying dust in suspension and sand by saltation. (b) Deflation hollows, such as the Qattara Depression, are basins scooped out by deflation; pedestal rocks are undercut at the base by low-moving sand; and yardangs are ridges left where softer rock bands parallel to the wind are abraded away (desert pavements, left after fine material is removed, are another example).

Example 6: Thar desert problems · 4 marks · Short answerHarder exam level

[4] Explain the problems caused by shifting sand dunes in the Thar desert and suggest remedies. (Evaluate)

Try it first, then show the solutionSolution

Dunes advance over fields, burying crops.
They cover roads, railways, canals and settlements.
Remedies: shelterbelts, planting grasses and shrubs to fix dunes.
Control overgrazing; careful irrigation and water harvesting.

Answer: Shifting dunes in the Thar bury fields and crops and cover roads, railway lines, canals and villages, worsening desertification. They can be stabilised by shelterbelts of trees, planting grasses and shrubs on dunes, controlling overgrazing and managing land and water carefully.

Case-study practice (Section D style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 8-mark question split into 3 + 1 + 2 + 2 marks.

A desert diary (source-based)

Read the imaginary diary and answer.

'Morning: we passed a rock shaped like a giant mushroom. Noon: the wind swept away all the sand from a gravel plain; only tightly packed pebbles remained. Evening: we camped beside a crescent of sand whose two horns pointed towards the east. The wind had blown from the west all day.'

(i) · 3 marks
Identify the three landforms described.
Answer
Answer: Pedestal (mushroom) rock; desert pavement (reg); barchan dune.
1 mark each.
(ii) · 1 mark
Why did the horns of the crescent point east?
Answer
Answer: Barchan horns point downwind; the wind blew from the west, so they pointed east.
1 mark.
(iii) · 2 marks
Which process formed the noon landform, and how?
Answer
Answer: Deflation: the wind removed the fine sand and dust, leaving coarse pebbles packed together.
1 for process; 1 for mechanism.
(iv) · 2 marks
Why are these landforms common in hot deserts? Give two reasons.
Answer
Answer: Dry, loose material and sparse vegetation let strong, steady winds erode and deposit freely; large daily temperature ranges produce plentiful sand.
1 each.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

[4] Formation of pedestal rocks. (4 marks)

Step	Marks
Abrasion by sand-laden wind.	1
Sand moves close to the ground.	1
Base undercut more than top.	1
Mushroom shape; softer base speeds it.	1

[7] Erosional and depositional work of wind. (7 marks)

Step	Marks
Conditions in hot deserts.	1
Processes of erosion.	1
Deflation hollows.	1
Pedestal rocks and yardangs.	1
Desert pavement.	1
Dunes and types.	1
Loess with examples.	1

Where students lose marks in Aeolian Landforms

The slips examiners see most often, and what to write instead.

Mistake: Barchan horns drawn pointing upwind
Confusion with parabolic dunes.
Wrong working
Barchan horns point towards the wind.
Right working
Barchan horns point downwind; parabolic horns upwind.
Do this: Horns follow the wind in barchans.
Usually costs: 1-2 marks.
Mistake: Mixing deflation and abrasion
Both are wind erosion.
Do this: Deflation removes loose particles; abrasion scrapes solid rock with sand.
Usually costs: 1 mark.
Mistake: No examples
The syllabus asks for examples from India.
Do this: Thar barchans and longitudinal dunes; Qattara; northern China loess.
Usually costs: 1 mark.
Mistake: Saying loess is deposited inside deserts
It is mostly laid down far from its source.
Do this: Dust travels in suspension and settles beyond the desert.
Usually costs: 1 mark.
Mistake: Forgetting the slip face in dune diagrams
Key feature omitted.
Do this: Show gentle windward slope and steep leeward slip face.
Usually costs: 1 mark.

Practice questions on Aeolian Landforms

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · Very short answerExam level
What is deflation?
Hint
Lifting away.
Answer
The removal of loose, dry particles from the surface by wind.
Q2 · 1 mark · Very short answerExam level
What is loess?
Hint
Fine dust.
Answer
A thick deposit of fine, wind-blown dust (silt).
Q3 · 1 mark · MCQExam level
A long sand ridge parallel to the prevailing wind is a:
(a) Barchan
(b) Transverse dune
(c) Seif dune
(d) Parabolic dune
Hint
Longitudinal.
Answer
(c) Seif dune.
Q4 · 1 mark · Very short answerHarder exam level
Name a large deflation hollow in Egypt.
Hint
Below sea level.
Answer
The Qattara Depression.
Q5 · 4 marks · Short answerHarder exam level
[4] Distinguish between transverse and parabolic dunes.
Hint
Orientation, horns, sand, vegetation.
Answer
(1) Transverse dunes are ridges at right angles to the wind. (2) They form where sand is abundant and winds are moderate. (3) Parabolic dunes are U-shaped with horns pointing upwind. (4) They form where vegetation anchors the horns, on coasts and semi-arid margins.
Q6 · 4 marks · Short answerHarder exam level
[4] Explain the role of attrition in deserts and its result.
Hint
Grain collisions.
Answer
(1) Wind-blown grains collide with one another during transport. (2) They break into smaller pieces. (3) Their corners are worn off, making them round and smooth. (4) Desert sand therefore consists of fine, well-rounded, often frosted grains.
Q7 · 4 marks · Short answerHarder exam level
[4] How do humans increase wind erosion?
Hint
Grazing, ploughing, vegetation.
Answer
(1) Overgrazing removes grass cover. (2) Ploughing of marginal dry lands loosens soil. (3) Cutting shrubs and trees for fuel exposes the surface. (4) Vehicles and construction disturb crusts; together these speed deflation and desertification.
Q8 · 4 marks · Short answerHOTS / competency
[4] A barchan dune moves 20 m a year and is 2 km from a highway. Calculate how long it will take to reach the highway and explain the process of its movement.
Hint
Convert km.
Answer
(1) 2 km = 2,000 m. (2) Time = 2,000 / 20 = 100 years. (3) Wind pushes sand up the gentle windward slope; it slides down the steep slip face. (4) Repeated, this shifts the whole dune downwind, so it advances towards the highway.
Q9 · 4 marks · Short answerHOTS / competency
[4] 'Loess is both a blessing and a problem.' Discuss.
Hint
Fertility versus erosion.
Answer
(1) Blessing: fine, porous loess forms very fertile soils for farming (northern China, Mississippi valley). (2) It can be dug easily, even for cave dwellings. (3) Problem: it erodes very quickly into gullies when vegetation is removed. (4) The eroded silt loads rivers like the Hwang Ho, raising beds and causing floods.
Q10 · 7 marks · Long answerHarder exam level
[7] (a) Explain the types of sand dunes. [4]
(b) Explain the formation of loess, with examples. [3]
Hint
(a) four types; (b) process and examples.
Answer
(a) (1) Barchan: crescent, horns downwind; one-directional wind, little sand (Thar). (2) Seif: long ridges parallel to wind (Thar, Sahara). (3) Transverse: across the wind, abundant sand. (4) Parabolic: horns upwind, anchored by vegetation; star dunes from multi-directional winds. (b) (1) Fine dust lifted from deserts or glacial outwash. (2) Carried in suspension and deposited far away in thick layers. (3) Loess Plateau of northern China (from the Gobi); Mississippi valley; fertile but erodible.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.What is reg?Show answer
A stony desert surface (desert pavement) of closely packed pebbles.
2.Why are desert sand grains rounded?Show answer
Because of attrition as they collide during transport.
3.Which dune forms where winds blow from several directions?Show answer
A star dune.
4.Which river is named after the colour of loess?Show answer
The Hwang Ho (Yellow River).
5.What is a slip face?Show answer
The steep leeward slope of a dune down which sand slides.
6.Which Indian desert has barchans and longitudinal dunes?Show answer
The Thar desert of Rajasthan.

Best order to study it

Processes of wind erosion and transport.
Ideal conditions in hot deserts.
Erosional landforms.
Sand dunes and types.
Loess; problems and remedies.

Quick revision checklist

The night before the exam: can you do each of these without looking?

Erosion: deflation, abrasion (near ground), attrition; transport: suspension, saltation, creep.
Conditions: aridity, loose sand, sparse vegetation, strong winds, big temperature range.
Erosional: deflation hollows (Qattara), pedestal rocks, yardangs, desert pavement (reg).
Dunes: barchan (horns downwind), seif (parallel), transverse (across), parabolic (horns upwind), star.
Loess: fine dust deposited far away; northern China, Mississippi valley; fertile but erodible.
Thar: barchans and longitudinal dunes; stabilise with shelterbelts and grasses.

Aeolian Landforms: frequently asked questions

Is water important in deserts too?

Yes. Occasional heavy rain causes sheet floods and flash floods that shape wadis and alluvial fans, but wind is the dominant agent on most desert surfaces.

Are there yardangs in India?

Yardangs are best developed in the large deserts of Central Asia, Iran and the Sahara; for Indian examples of aeolian landforms, use the dunes of the Thar.

Do I need to know zeugen?

The syllabus names deflation hollows, pedestal rocks, yardangs and desert pavement; zeugen can be mentioned for interest but is not required.

Based on: CISCE ISC 2028 Geography (853) syllabus (Classes XI and XII); CISCE Regulations for the ISC Examination Year 2028 (Class XI internal examination)