Let’s know a little bit more about our earth. After knowing the erosional landforms of wind, now it is time to move forward towards its depositional creatures, contribute to shaping the surface of the earth.
Do you know, our mother Planet Earth keeps on forming and destroying something every second of time without any break. At some part and corner of the Earth there must be new life or structure, chemical, mineral, or something that may be beyond our imagination, is under the process of formation and destruction. Here, in this post, I'm going to discuss one such process of the creation of a depositional landform of wind, among various processes which are continuously building and destroying something on the planet earth.
The Depositional Landform of Wind
When the speed of wind gets slowed down, then all eroded material like sand particles, sand soil which carried along with them, starts depositing on the surface of the earth, which results in the formation of new shapes and landforms, named as Depositional Landforms of wind.
1. Sand Dunes
It is a famous depositional landform of wind in desert areas. These are small hills or mount or ridge shaped structure of loose sand. Sand dunes are formed, when wind deposits all eroded and transported material behind an obstacle.
This obstacle can be any bush, uneven land, piece of rock, house, and maybe any skeleton of dead animals like a Camel.
Every Dune has two sides, one is a Windward side and the second one is Slipface.
- Dune's Windward side is the side of wind blowing direction which pushes material up.
- The Slipface is the side without wind, this side is comparatively smoother than the Windward side.
Also, some features of Sand Dunes are:
- An area having a collection of sand dunes called dune belt or dune field.
- A large dune field is called an Erg.
- The height of Sand Dune generally found around 1-2 meters to 150 meters and in some extreme cases, it may reach up to 300 meters.
- Length may vary from 3 km to 150 km.
- These are found mostly in Deserts, but also in coastal areas and river basin areas.
- These dunes are moving continuously at a slower pace.
- The speed of moving dunes varies from 5-30 meters per year.
Sand dunes are found in various shapes and known with different names (on the basis of their shape), in different areas or regions, some among them we will discuss under their separate name heading.
For example, found in Sahara Desert, Africa, Colorado, Thar India, etc.
Types of Dunes on the basis of Shape
Here are some landforms of dunes, on the basis of shape.
Barchan or Crescent-shaped Dunes
- It is a ‘C’ shaped or crescent-shaped sand dunes with two “horns” facing downward.
- The windward side of Barchan has a steep slope and the Slipface side slope has a smooth and slow slope.
- Barchan is a Turkish word because it was first shown in Turkistan.
- It is formed when there is a large amount of sand in the desert and the availability of a steady wind is blowing from one direction.
However, the great change in the wind direction can destroy the crescent form of a dune.
- The height of Barchan may vary from 9-30 meter and base width of 370 meters, which is measured perpendicular to the wind.
For example, the Sahara desert in Africa, the Gobi desert in Asia are the areas of most notable, where the Barchan dunes are found.
Seif or Longitudinal Dunes
- These dunes are named as ‘Seif’ after the Arabic word means ‘Sword’.
- These are long narrow, linear dunes that are formed due to the bidirectional wind or oriented in a direction parallel to the prevailing wind.
- Here bidirectional wind means two or more winds blowing at acute angles to each other.
- The height of these dunes is around 90 to 300 meters.
- The length of these dunes is up to 160 km or in some areas it reaches up to 300 km and so, visible in the satellite image.
For example, These dunes are very common in the Sahara desert, Libya, and Southern Iran.
These dunes are also named as Longitudinal due to its long axed and ridges extend along the resultant direction of sand movement.
- These dunes look like a star shape that is why known as star dunes.
- These are formed in areas when the direction of the wind changes a lot, frequently.
The winds which blow in one direction results to form star dunes.
- These dunes have three or more than three ‘arms’ usually irregularly shaped. Every dune has its own peak.
- The height of star dunes is found up to 500 meters.
They are found in deserts of Sahara, Central Asia, and Namibia.
- These are long, large, strongly asymmetrical elongated dunes, lying at right angles to the prevailing wind direction.
- These dunes are formed when the wind blows only in one direction.
- These dunes are in a wavy line and parallel to each other.
- They also formed a deep valley between their neighboring dunes.
- They generally form in areas of sparse vegetation and abundant sand in coastal areas.
- These dunes are U-shaped or V-shaped mounds of sand with elongated arms that extend upwind behind the central part of the dune.
- These dunes have only one set of arms that trail upwind, behind the leading nose.
- They do not attain much height.
- These are generally found in the semi-arid and coastal regions.
2. Ripple Marks
These are formed when winds or water currents flow across loose sand or sediments. Ripple Marks are the wavy shaped ridges that are formed in response to the wind blowing along with the layer of loose sand and sediments. They are of two types:
- Symmetrical ripple marks
- Asymmetrical ripple marks
It is derived from the German word ‘Loss’. These are aeolian sediments which are formed by the accumulation of windblown silt or dust. When the windblown away along with the very fine particles of sand and soil, deposit it into the far areas.
- Loess is homogeneous, porous, friable, pale yellow or buff, typically non-stratified and often calcareous.
- Loess soils are among the most fertile soils in the world.
Found in the Great Plains of North America, Northern China, Central Europe, and parts of Russia and Asia.
All these above-mentioned landforms are just a little preview of nature’s creation on this Earth, many millions to know.
Tell me that, do you really think these landforms are formed by the wind in the long term?
Write to me with your honest opinion, information, and insight on the topic, which will definitely inspire us.