Deatiled information of each aeolian landforms

1. AEOLIAN LANDFORMS
ZARISH ABID
Student at
LAHORE COLLEGE FOR WOMEN UNIVERSITY

2. AEOLIAN LANDFROMS
• Aeolian/Eolian processes are those
related to wind action
• Aeolus the Greek word God of the
winds
• Wind has capabilities similar to that
of running water for erosion,
transportation and deposition
• But at much lower order of
magnitude.
• Wind always makes features toward
its direction Terraces, Loess Plateau, China

3. WIND EROSION
• The erosive effect of
wind movement is
simple and clear-cut
• It has three
categories
1. Deflation
2. Abrasion
3. Attrition
Wind erosion of soil at the
foot of Chimborazo, Ecuador

4. WIND EROSION
1. Deflation:
• The process by which wind removes small surface materials.
• Loose particles by blowing them into the air or rolling them along the
ground.
• 5 to 8 cm in diameter
• Deflation produces wind pits, deflation, depressions and basins.

5. Processing of Deflation

6. WIND EROSION
2. Abrasion:
• When wind blows faster, these particles act like sand paper on the rocks.
They are known as tools of wind and wear down the rocks by scrapping,
rubbing, undercutting, scouring and grooving etc. This action is known as
abrasion.
• Wind abrasion does not construct.

7. WIND EROSION
• Sculptures
o Zeugen
o Mushrooms
o Demoiselles
o Yardang
• The largest grains carried by the wind move along in the lower 20 cm (8 inch)
or so.
• Almost all wind abrasion takes place within 2 m (6.6 feet) of the ground.

8. A rock sculpted by wind erosion in the
Altiplano region of Bolivia

9. WIND EROSION
3. Attrition:
• The sand particles in
the air also strike
against one another
and get reduced and
rounded by friction.
This processes is called
attrition.
Reduction of large stones by attrition
process

10. WIND TRANSPORTATION
• Rock material are transported in much the same fashion as they are moved
by water, but less effectively. Strong turbulent wind can lift and carry
thousand of tons of suspended dust. The transportation on rock particles by
wind take place in the following ways:
1. Suspension
2. Saltation
3. Traction

11. 1. Suspension:
• The finer sand particles such as silt and clay are moved by the wind, high in
the air.
• When they land, it is often because they have combined with raindrops and
fall with the rain.
WIND TRANSPORTATION

12. WIND TRANSPORTATION
2. Saltation:
• The transporting process of grains, in a bouncing motion along the ground, is
called, saltation. As the sand moves, it hits other grains which cause them to
bounce up in the air.
• If it lands on a sandy surface, it will cause other particles to be disturbed,
bounce up and they too will be carried, thus starting off a chain reaction.

13. WIND TRANSPORTATION
3. Traction:
• Larger particles are rolled or pushed along the ground, by the wind, in a
stream in a process called traction.
• It is estimated that, perhaps three-fourth of the total volume of all wind-
moved material in dry lands is shifted by either traction alone or by traction
and saltation combined.

14. Wind Transportation

15. FORMATION OF DESERTS BY WIND
ACTION
1. Hamada or Rocky Desert:
• This consists of extensive areas of bare rocks from which all fine materials
have been removed by deflation while abrasion polishes and smooths the
rock surfaces.
• One of the largest Hamada is Hamada el hamra, in Sahara of Libya.
• Which covers an area of almost 20,000 square miles.

16. Rocky Desert of Libya

17. FORMATION OF DESERTS BY WIND
ACTION
2. Erg:
• It consist of an undulating plain of sand, the surface of which is blown into
ripples and sand dunes.
• In Turkestan, this type of desert is known as Koum.
• The sand sea of Egypt and Libya is good example of erg.

18. Erg, the dunes of great sand sea near
Siwa, Egypt

19. FORMATION OF DESERTS BY WIND
ACTION
3. Reg or Stony Desert:
• The surface is covered with boulders, angular pebbles and gravels which
have been produced by daily temperature changes.
• In Libya and Egypt they are called Serir.

20. Stony desert of Libya and Egypt

21. EROSIONAL LANDFORMS OF WIND
• If the wind is slow, it can only carry very minute particles of sand and dust
• Areas where there is little or no vegetation are usually the most effected
places that experience shaping due to wind.
• The wind also plays an important role in moving and reshaping dunes.
Examples of landforms that are obvious are Yardangs, Desert pavements,
Deflation hollows etc.

22. EROSIONAL LANDFORMS OF WIND
1. Deflation Hollows:
• When the sand is carried away over long distances by the wind, depressions
are formed in the area from which is lands in. These depressions are called
deflation hollows
• They are commonly found in non-mountainous arid regions.
• These depressions also tend to collect rainwater and hold this water for a
time depending on evaporation rates through the stones.
• The Faiyum Depression in Egypt lies 40 m (130 feet), below sea level.
• The Great Bowl of Western USA is also formed, a depressional feature by
wind deflation.

23. Faiyum Depression in Egypt

24. EROSIONAL LANDFORMS OF WIND
2. Desert Pavement:
• The stony surface, although the surface covering of stones may be very thin.
Pavements are commonly covered with stones rather than sand.
• This may be due to the wind blowing away the finest material leaving the
stones behind as they are the bigger particles, results in the stones remaining
on top.
• Desert pavements can be used as mulch for plants or as a shelter for ants and
rodents.

25. Desert pavement formed in the
Mojave Desert as a result of deflation

26. EROSIONAL LANDFORMS OF WIND
3. Desert Varnish:
• “The wind rubs, scorch and work like a sandpaper on rock fragments, for
this their surface is shined out, and is known as desert varnishing”.
• Wind transports clay-sized particles that chemically react with other
substances at high temperatures. The coating is formed of iron and
manganese oxides.
• Desert varnishing serves as an important dating tool, because longer a rock
surface has been exposed to the wind/air, the greater is the concentration of
the oxide coating and thus shiner the colour.

27. Ancient people carved these petro glyphs into
desert varnish near Canyon lands National
Park in Utah

28. EROSIONAL LANDFORMS OF WIND
4. Yardang:
• “Yardang” is the product of wind abrasion, which are low ridges, and they
are formed parallel to prevailing wind direction
• They are form in dry sand areas where they are affected by strong winds,
especially where bedrock is fairly soft and unprotected by vegetation.
• They are separated, by troughs that are scooped out by wind abrasion.

29. Scenery of Dunhuang Yardang National Geo park in china.

30. EROSIONAL LANDFORMS OF WIND
5. Zeugen:
• “Zeugen” is a German word used for landscapes that are tabular masses,
having layers of soft rocks, lying beneath a surface layer of more resistant
rocks
• They look like “ridge and furrow” by sculpting effects of wind abrasion.

31. EROSIONAL LANDFORMS OF WIND
• Process of making of Zeugen:
• Mechanical weathering initiates their formation, by opening up joints of
surface rocks. Wind abrasion further eats into the underlying soft rocks layer,
hence deep furrows are developed. The hard rock’s then stand above the
surface like ridges, and some overhang named as Zeugen.
• Such tabular blocks of Zeugen stand 3 to 30m above the furrows. By
continuous wind abrasion, it gradually lowers zeugen and widens the
furrows.

32. Tibesti Massif (Sahara) Zeugen with horizontal strata of hard and soft rocks

33. EROSIONAL LANDFORMS OF WIND
6. Inselberg:
• “The isolated landform that rise abruptly from the surroundings plains with steep-
sided ridges is referred as Inselbergs”.
• Inselbergs are mostly found in desert and semi-arid landscapes for example;
Northern Nigeria, Western Australia and Kalahari Desert.
• Bonhardt, is the type of Inselbergs. They are composed of highly resistant rocks and
have dormal or rounded form.
• Due to weathering and erosional processes taking place on the surroundings terrain,
it lowers the area, leaving the resistant bornhardt standing high. They are stable
parts of landscape and may persist for tens of millions of years.

34. Ayer's Rock Inselbergs in Australia

35. EROSIONAL LANDFORMS OF WIND
8. Playa Lake/Salina:
• “A playa lake is an ephemeral body of water, which means it only exists
temporarily throughout the year.”
• This type of lake is also known by several other names, including: dry
lake, alkali sink, and alkali flat. These last two names are derived from
the physical characteristics of the playa lake bed: covered in fine-grain
sediment with a high alkali salt content.
• Playa lakes may be very large in surface, but shallow in depth. Found
in arid and semi-arid climates.
• Southern High Plains of Texas and New Mexico in the US is home to a
concentration of around 22,000 lakes.

36. The Salar de Uyuni in Bolivia, largest playa lake in
the world.

37. EROSIONAL LANDFORMS OF WIND
9. Driekants/Ventifacts/Beveled Stones:
• When the stones roll away from their position they develop many edge
shapes such stones are known as the driekants.
• Due to abrasion, it surface become smooth and its shape resembles a
tetra-hadron or a prism.
• The wind has eroded the surfaces that appears gray.
• These wind faceted pebbles, combine together to form desert
pavements.

38. A Dreikants from the Wind River Basin,
Wyoming, USA.

39. EROSIONAL LANDFORMS OF WIND
10. Earth Pillars:
• “The protected soft rock stands like a pillar below the hard rock
and is known as Demoiselle or Earth Pillars.”
• There are many areas, which are made of hard rocks. Winds
subject the upper parts of the rocks to abrasion but lower parts
remain protected.
• These earth pillars are round or many faceted smooth or rough
according as wind has attacked them from one side or from all the
sides steadily.

40. Earth pillars fairy towers rain wash erosion in terrace
sediments Spiti Valley Himachal Pradesh India Asia

41. EROSIONAL LANDFORMS OF WIND
11. Mushroom Rock/ Pedestal Rock:
• “Grooves and hollows are cut in the rock surfaces, carving them into
fantastic pillars called rock pedestals or mushroom rocks”.
• The sand blasting effect of winds against any projecting rock masses
wears back the soft layers, so that an irregular edge is formed on the
alternate bands of hard and soft rocks
• These rock pillars will be eroded near their basis, where friction is
greatest. This process of undercutting produces a mushroom like rocks,
called “gours”.

42. Mushroom rock, Marquette Kansas Pedestal rock in Northern Arizona
Desert

43. DEPOSITIONAL LANDFORMS OF WIND
• It has been estimated, that some dust grains travel as far as 3700km before
they are finally deposited on land or sea.
• The depositional work of wind is mostly related to two characteristic
landforms.
1. Sand Dunes
2. Loess Deposits

44. Global distribution of major deposits of Aeolian derived sediments

45. DEPOSITIONAL LANDFORMS OF WIND
1. Sand Dunes:
• “When the loose wind is blown sand is heaped into a mound or low hill, it is
called sand dune”
• They are active when bare of vegetation, move forward and constantly
changing their shape form under winds.
• They may be inactive or fixed when dunes are covered with vegetation, has
taken roots and serves to prevent shifting of the sand.

46. Active Sand Dunes Big Bay, Western
Fiord land
Profile view of a sand dune.

47. VARIETIES OF SAND DUNES
1. Barchans and Crescent Dunes:
• “A barchans in a crescent shape with the horns of the crescent pointing downward”.
• It occurs as an individual dune migrating across a non-sandy surface, they may also
be found in groups
• Sand movement is not only over the crest from windward side to slip face, but also
around the edges of crescent to extend the horns.
• Barchans are formed where strong winds are blown consistently from one direction
• They tend to be the fastest moving of all dunes and are found abundant in deserts
except those of Australia. They are most widespread in deserts of “Thar” and
“Takla-Makan”.

48. Barchans Dunes, Paracas National Park, Peru

49. VARIETIES OF SAND DUNES
2. Transverse Dunes:
• They occur where supply of sand is much greater, normally the entire
landscape is sand covered.
• Their convex side faces the prevailing direction of winds.
• Their crests are perpendicular to wind vector and aligned in parallel waves
across land.
• They migrate in the same downward fashion, if sand supply decreases; they
are likely to break up into barchans

50. Great Sand Dunes National Park. Alamosa, Colorado

51. VARIETIES OF SAND DUNES
3. Parabolic Dune:
• It also has a crescent shape, but concave side is the windward side, so points
of crescent lie upward, thus parabolic dunes looks like a depression hollow
from above.
• They develop longer sides than barchans.
• In deserts, develop in association with deflation hollows and also frequently
along coastlines.
• Its looks like a horse-shoe shape.

52. Red Dune Sea at Sesriem, Namibia Shape of Parabolic Dune

53. VARIETIES OF SAND DUNES
4. Longitudinal Dunes or Seifs:
• “Seif” is an Arabic word meaning “Sword”. They are long narrow dunes,
usually occur in multiplicity and generally parallel in arrangements
• They are a few dozen to a few hundred feet in height, a few tens of yards in
width, and have a length measured in miles or even tens of miles.
• Longitudinal dunes are found in Sahara desert, south of Qattara Depression,
in Thar and in, West Australia Desert

54. Longitudinal Sand Dune, Sahara,
Morocco

55. VARIETIES OF SAND DUNES
5. Coastal Dunes:
• Winds are also active in dune formation along many stretches of oceans and
lake coasts.
• Coastal sand dunes form on landward side of some beaches. They develop is
sand beaches dry out and onshore winds are sufficiently strong and
persistent to blow the finer sand particles inland.
• The largest area is probably along the south western coastline of France,
where such dunes extend for 240 km along the shore and reach inland for 3
to 9 km

56. Sand dunes along the Oregon coast

57. DEPOSITIONAL LANDFORMS OF WIND
2. Loess Deposits:
• “Loess is wind deposited silt, that is fined grained, calcareous and usually
buff-coloured.”
• It was first identified in Rhine valley, as long as 1821, which is how it got its
German name(loess mean loose in German).
• It also exists in France’s Paris basin, in Danube valley of eastern Europe and
in large areas of southern and central Russia
• But the thickest loess accumulations lie in asia, especially in east central china

58. Loess Deposits in Palouse Washington

59. DEPOSITIONAL LANDFORMS OF WIND
2.1 Distribution of Loess Deposits:
• Most deposits of loess are in mid latitudes, where some are very extensive,
particularly in united states, Russia, china and Argentina
• Most deposits are laid down as a mantle over pre-existing topography, with a
considerable thickness, more than 60m (200 feet) in some cases.

60. Global distribution of major deposits of loess sediments

61. References
• Physical geography by Mian Muhammad Anwar
• University Physical geography by M. Iftikhar Ch.
• Physical Geography in Diagrams, Fourth GCSE Edition by
R.B.Bunnett, Pearson Edition
• Physical Geography by Das Gupta and A.N.Kapoor
• http://www.beachapedia.org/Aeolian_Transport
• https://desertlandforms.weebly.com/desert-landforms.html

62. THANK
YOU!