it is a complete presentation of the action of wind landform characteristics.

1. wind
landform
characteristics
ACTION
OF

2. Group E
Group Members:
¤Ellin Sumaia Zaman (2012256158)
¤Arifa-Tul-Rayhana (2012156182)
¤Nafis Foysal (2010656145)
¤Md. Ohid Zaman (2010656187)
¤ Md. Rakib Mia (2010856107)
¤Most. Rotna Khatun (2012056116)
¤Md.Zahid Hossain (2010856126)
¤Urmi Roy (2012256135)

3. LAYOUT
₰ Introduction
₰ Factors of erosion due to wind
₰ Process of erosion
₰ Transportation work of wind
₰ Erosional landforms due to wind
₰ Depositional landforms
₰ Conclusion

4. LAYOUT
Wind
Wind is moving air and is caused by differences in air pressure within our atmosphere.
Air under high pressure moves toward areas of low pressure. The greater the difference
in pressure , the faster the air.
Wind transports small particles, such as silt and clay, over great distances, even halfway
across a continent or an entire ocean basin. Particles may be suspended for days.
Factors of erosion due to wind
 Wind velocity
 Tools of erosion
 Variation of temperature
 Composition of rock
 Low precipitation
 Nature of vegetation

5. LAYOUT
Transp
ortation
work of
wind
According to Bagnold(1974) and Warren(1979),
Saltation:
– usually occurs in the moving air layer that’s closest to the
earth surface.
– when wind velocity exceeds the threshold velocity, the dust is
lifted up by the aerodynamic force at an angle of 6-12
degrees to the wind flow and falls back to the ground on its
own propagation stream.
Surface creep:
– surface creep occurs when soil particles larger than .5 mm in
diameter are dragged over the surface of the land because
they are too heavy for the wind to lift.
– as the particles roll and along the surface , they bump into
each other.
Suspension:
– when materials are very less than 0.15mm in diameter
– they can be easily picked up by the wind
– example Sahara desert.

7. LAYOUT
Process
Of
Erosion
Deflation
Deflation occurs in rocky areas when air enters into crack in rock.
This air is trapped in cracks by the rising tide, as waves crash
against the rock the air inside the crack is rapidly compressed and
decompressed causing cracks to spread and pieces of rock to
break off. Compression is one of the main processes that result in
the creation of caves.
Abrasion
Abrasion is when rocks and other materials carried by the sea are
picked up by strong waves and thrown against the coastline
causing more material to be broken off and carried away by the
sea.
Attrition
Attrition is when material such as rocks and stones carried by waves hit
and knock against each other wearing them down. As these materials
are worn down sand and rounded beach pebbles are formed.

8. LAYOUT
Erosional landform
ỽ Deflation hollows
ỽ Ventifact
ỽ Mushroom
ỽ Inselberg
ỽ Demoiselle
ỽ Zeugen
ỽ Yardang
ỽ Desert pavement
ỽ Wind bridge and window

9. LAYOUT
Erosional landform
Characteristics
Deflation Hollows/Blowouts:
removal of loose particles from the ground by
the action of wind.
And, deflation causes a shallow depression by
persistent movements of wind, they are called
as deflation hollows.

10. LAYOUT
Mushroom or Pedestal rock
- also known as a rock pedestal or gour.
- is a common mushroom-shaped landform.
- in dry areas with little vegetation to obstruct
aeolian particle movement.
- frequent high winds.
- and a steady but not excessive supply of
sand.
Yardangs
- define as spectacular stream lined, sharp
and sinuous ridges.
- extend parallel to the wind .
example: Boukou area near the Tibesti
Mountains of Chad.

11. LAYOUT
Zeugen
- also called perched or mushroom rocks
- related to yardangs
- where sand laden wind is funneled by
topography, even hard rock maybe fluted,
grooved, pitted, and polished by sand blasting.
Windy Point, near Plam Springs, in the Mojave
Desert, California.
Ventifacts
- cobbles and pebbles on stony desert
surfaces often bear faces called ventifacts
- the number of edges or keels they carry is
sometimes connoted by the German terms
-Einkanta
-Zweikanter
-Dreikanter

12. LAYOUT
Demoiselle
- rock pillars which stand as resistant rocks
above soft rocks as a result of differential
erosion of hard and soft rocks.
Inselberg
- a body of rock resistant to erosion, such as
granite, occurring without a body of softer
rocks, is exposed by differential erosion
and lowering of the surrounding landscape.
Example: Olga rocks in central Australia.

13. LAYOUT
Desert pavement
- formed by surface of angular, interlocking
fragments of pebbles, gravel in arid areas.
- it also called reg (western Sahara)
serir(eastern Sahara)
gibber(Australis)
Wind bridge and windows
- sometimes the holes are gradually widened
to reach the other end of the rocks to create
the effect of a window
- window bridge are formed when the holes
are further widened to form an arch-like
feature.

14. LAYOUT
Depositional erosion
Along sea line Atlantic coast of the United States from Massachusetts to Florida
Along river valleys in arid regions Sand dunes , USA , river valley in Egypt, large plains in America
Desert area Almost everywhere in desert
Position of depositional landform

15. LAYOUT
Wilson, Cook and warren made a classification of wind storage landforms based on their
shape and volume. They are;
Ripple
Ripple is an depositional of wind waves with a height of 0.001 to 20 cm and a wave
length of 4 cm.
Drass
Usually 1 to 3 kilometers wavelength and 30 to 200 meters heigh large size sand piles
are called drass.
Sand dune
A sand dune is usually 40 meters or 200 meters long and has a height of 1 to 30
meters. Sand dunes of different shapes and sizes are found in different desert regions.
Types of sand dune
¤ Longitudinal sand dune
¤ Blowout dune
¤ Parabolic dune
¤ Star
¤ Seif
¤ Shit and strain
¤ Transvers dune
¤ Barchan
¤ Dome dune
¤ Reversing dune

16. LAYOUT
Types of sand dune
Blowout dune Barchan dune Blowout dune
Barchanoid ridges dome dune
Transvers ridges

17. LAYOUT
Loess Plains:
- Winds deposit light and soft soil over a large area like a blanket, these are
known as plains of Loess.
- ‘Loess’ is a word of German language which means yellow colour, porous
soil with very soft particles.
- Generally, these particles are of the same size. This soil does not have
layers and it is friable. When we press it crumbles easily.
- During rainfall it becomes very sticky, on the other hand in summer it
becomes very dry.
- Loess is found in China, Europe, North America, South America and Africa.
- The name “Yellow river” in China is also given on the basis of their soil
because when it mixes with river water, water appears to be yellow in
color.

18. Thank you
for your kind attention