DESERT RELIEF: MAIN CHARACTERISTICS - GEOGRAPHY - 2024

The desert relief typically has plains or plains, a variety of dunes and plateaus. In some cases, when the deserts are closer to the coasts or there is a slightly higher presence of water, wadis and salinas can be seen.

Deserts are arid land areas characterized by low rainfall with sparse vegetation and fauna. The rains generally do not exceed 25 cm per year, or what is equal to 10 inches.

Deserts occupy more than a fifth of the earth's surface and are found on every continent. They are usually associated with intense sun and sand, however, they can also be cold.

Main characteristics of deserts

Deserts are arid land areas characterized by low rainfall, low vegetation and fauna. The rains generally do not exceed 25 cm per year, or what is equal to 10 inches.

Vegetation is equipped to survive low rainfall and humidity. For miles, where the only sources of water are early morning rains and mist, you won't find as much plant life.

The plants that grow are xerophilous such as cacti, palms and bromeliads, which have thorns in their hard bark to avoid predators that drain the water they have stored to survive long periods.

There is the possibility that some plants will grow during the short-lived rainy season but die quickly after it ends.

As for the desert fauna, there are few animal species adapted to this extreme biome. Most of the animals that live there have rough and hard skins that protect them from other predators and allow them to lose less water through the skin.

In addition, they are usually hidden during the day so as not to lose the little humidity they obtain. Reptiles such as desert iguanas, snakes or chameleons are often seen in this type of landscape, although we can also find coyotes, kangaroos, camels, vultures, tarantulas, rats, coyotes and scorpions.

There are four basic types of desert depending on the climate: hot and dry, semi-arid, coastal and cold.

The 10 largest deserts in square kilometers on the planet are:

1. Antarctic Desert (13,829,430)
2. Arctic Desert (13,726,937)
3. Sahara (9,065,253)
4. Arabian Desert (2,300,000)
5. Australian Wilderness (1,371,000)
6. Gobi Desert (1,300,000)
7. Kalahari Desert (930,000)
8. Patagonian Desert (670,000)
9. Syrian Desert (409,000)
10. Chihuahuan Desert (362,600)

Characteristics of the desert relief

The desert relief is made up of dunes, plains and plateaus.

1- Dunes

They are desert landforms that are built by the wind with smooth, uniform layers. They are mounds of sand that the wind moves, accumulates and shapes. The interior dunes of the desert are lacking in nutrients and water.

Dunes can be coastal or inland desert. The former, as their name indicates, are close to the coast but in the case of the desert, the dunes are inland. There is a great variety of dune classification according to the color of the sand, the direction of the wind, the type of sediment, etc.

On this occasion, in order to focus on the characteristic dunes of the desert and omit the coastal dunes, we will take as a reference the classification of the dunes according to the direction of the wind.

Types of dunes according to the wind direction

The formation of dunes according to the wind results from the influx of 3 factors: the speed at which the wind runs, the amount of sediment that it will displace and the amount of vegetation present.

According to their movement, the dunes are divided into five classes:

Parabolic dunes

They are shaped like an inverted "U" and point in the opposite direction of the wind. Their shape can best be appreciated from an aerial panorama and when formed successively they look like a tile roof.

Parabolic dunes typically have two arms and a peak that joins them. The top is oriented towards the direction where the prevailing winds travel.

Barjanes or barchanes

The slide is transverse so they form a "C" or half moon shape and their ends go in the direction of the wind. When the wind is constant, the shape of the curves is symmetrical.

They are usually flat, with little available sediment, no vegetation and rather low, reaching average heights of 9 to 30 meters but extensions between the tip of one arm and another of 365 meters.

They resemble parabolic dunes with the difference that the ends of the barjanes point to the prevailing wind direction while the arms of the parabolic are the opposite.

Transverse dunes

They are accumulations of abundant sand, no or scattered vegetation and predominantly uniform winds that shape long ridges separated by depressions and oriented at right angles obeying the stronger wind current.

The presence of several transverse dunes is reminiscent of ocean waves, which is why they are sometimes called the sand sea.

Longitudinal dunes

They are long ridges of sand that form more or less parallel to the prevailing wind and where the supply of sand is limited (Geological Routes Araucania, 2017). It is elongated and almost straight with an abundance of sand.

They are usually not very tall but they can be really long. In Arabia, Australia and North Africa they reach altitudes of 100 meters and lengths greater than 100 kilometers.

Star or pyramidal dunes

These types of dunes have more than two ridges (usually 3 or 4) that look like the arms of a star, which meet at a central point whose height can reach 90 meters. They are the consequence of winds of variable direction and a large amount of sand.

2- Plateaus / tables / hamadas and isolated hills

They are another type of geographical feature that the desert offers whose elevations have flat tops and very steep slopes. They have a platform appearance as they are flat at the top and sharply elevated on their slopes.

With the passage of time, the plateaus become very narrow due to the strong wind and then they are called isolated hills.

3- Plains

The desert plains are extensions of flat land that generally appear undulating due to the dunes that form on it. In other cases, the plains are covered with snow.

4- Wadis or Uadis

They are artificial deposits of dry river beds that only fill with water in the rainy season and dry up again when the rainfall ends, so they are not long-lasting.

5- Salinas or chotts

They are places that were once lakes or shallow salty ponds that due to the intensity of the sun, the water evaporates leaving only salt at the bottom.

References

1. BioEncyclopedia. (16 of 7 of 2017). Desert Obtained from BioEnccyclopedia: bioenccyclopedia.com.
2. String be. (16 of 7 of 2017). The 10 largest deserts in the world. Obtained from chainser.com.
3. Encyclopedia Britannica. (15 of 7 of 2017). Desert. Retrieved from Encyclopedia Britannica: britannica.com.
4. Geology.com. (16 of 8 of 2017). The World's largest Deserts. Retrieved from Geoglogy.com: geology.com.
5. George, P. (2007). Akal Dictionary of Geography. Madrid: Akal.
6. Julivert, M. (2003). Regional descriptions. Relief and natural regions. In M. Julivert, The Sahara. Lands, peoples and cultures (pp. 75-171). Valencia: University of Valencia.
7. Kalman, B., & Mac Aulay, K. (2008). The deserts. Ontario: Crabtree Publishing Company.
8. National Geographic. (15 of 7 of 2017). Deserts. Retrieved from National Geographic: nationalgeographic.com/environment/habitats/deserts/
9. Araucania geological routes. (16 of 7 of 2017). Types of sand dunes. Obtained from Geological Routes Araucania: rutageologica.cl.
10. Types of dunes. (16 of 7 of 2017). Obtained from Research Gate: researchgate.net.