Deserts

Libyan Desert

June 15, 2013, 3:28 am
Source: Wikipedia
Content Cover Image

Libyan Desert. Source: Roberdan, Flickr

The Libyan Desert is located in the northern and eastern part of the Sahara Desert, comprising the desert of western Egypt, eastern and southern Libya, and northwestern Sudan. In most of Upper Egypt, the desert encroaches very near the Nile, with a flood plain only a few kilometers wide.

The dimensions and area of the Libyan Desert is not precisely defined. The Egyptian portion is called the Western Desert (from the perspective of the Nile Valley) and comprises the New Valley Governorate and the interior part of the Matrouh Governorate of that country. The Libyan part includes the Districts of Kufra, Al Wahat and the interior of the Al Butnan District. The Sudanese part consists of Ash Shamaliyah and Northern Darfur. To the libyan Desert (i.e. east of the Nile) is the Eastern Desert and to the southeast is the Nubian Desert.

Although, like most of the Sahara, this desert is primarily sand plains, dunes, ridges, depressions (basins),  and hamada or stony plain, it does include striking diversity of landscapes including mountains like Jebel Uweinat, the Gilf Kebir plateau, and sand seas. The desert's Gilf Kebir plateau reaches an altitude of just over 1000 m, and along with the nearby massif of Jebel Uweinat is an exception to the uninterrupted territory of basement rocks covered by layers of horizontally bedded sediments, forming a massive sand plain, low plateaus and dunes. The highest point is Jebel Uweinat (also Mount Al-ʿUwaynāt - 6,345 feet or 1,934m) located near the meeting point of the borders of Egypt, Libya, and Sudan.  No rivers drain into or out of the area.

The Libyan Desert is barely populated apart from Egyptian oases of Siwa, Al-Baḥrīyah, Al-Farāfirah, Ad-Dākhilah, and Al-Khārijah and the Libyan oasis of Al-Kufrah.

Geography

Depressions and oases

caption Eastern Siwa Oasis. Source: NASA
caption Egyptian Oases in Libyan Desert
 
caption Kufra Oasis. Source: NASA
caption "Cave of the Swimmers" cave art

Qattara - Located in north west Egypt, Qattara is 285 kilometers (km) long and 135 km wide, about 19,500 km2 of land below sea level with a maximum depth of 133 meters (m). Within the Depression there are saline marshes under the northwestern and northern escarpment edges, and extensive dry lakes (dry lake beds) that flood occasionally.

The Moghra oasis in the northeast of the Depression has a 4 km² brackish lake and a Phragmites swamp. Salt marshes also occur and occupy approximately 300 km², although wind blown sands are encroaching in some areas.

About one-quarter of the depression area is occupied by dry lakes composed of hard crust and sticky mud, and occasionally filled with water.

There is one permanent settlement in the Qattara Depression, the Qara Oasis. The oasis is located in the western most part of the depression and is inhabited by about 300 people. The Depression is also inhabited by the nomadic Bedouin people and their flocks, with the uninhabited Moghra oasis being important in times of water scarcity during the dry seasons.

Siwa Oasis - Located west of Qattara close to the Libyan border, extends in an east-west direction 82 km long and has a maximum width of 28 km, but narrows in places to 2 km. . At its maximum depth it is about 25 m below sea level.

There are approximately 18 lakes in the depression. Each are surrounded by salt and brackish marshlands, which are the remains of once larger lakes. 

The paleocoastline of these ancient lakes can be seen 8-12 m below sea level. The present lakes cover approximately 7 km2 as well as another 10 km2 of marshland consisting of Phragmites and Typha swamp.

The lakes may dry up in the summer, or shrink considerably. All of the lakes are saline, but are supplied with freshwater from 18 underground springs. These springs supply water that is believed to have been underground for 30,000 to 50,000 years.

Only Chara and other algae, as well as a couple of species of fish, are able to survive in the brackish waters of the lakes.

It sustains a community of approximately 23,000.

Fayum Depression (also Faiyum, Al-Fayyum and other variants) - Located 60 km southwest of Cairo, covers about 12,000 km2. It inludes the saline Lake Qarun (Birket Qarun) and the two artificial Wadi el-Rayan lakes. Lake Qarun was created by ancient Egyptians using Nile water (from about 1980 bc about 323–246 bc) but is now sustained by pumped water that evaporates in its basin.

Bahariya Oasis - Located 300 km from Cairo, supports agriculture and more recently tourism.

Farafra Depression - Notable for its "White Desert" of exposed chalk formations and for the Farafra Oasis

Dakhla Oasis - Located about 800 km southeast of Cario, it is 80 km long and 25 km wide at its maximum.

Kharga Oasis - Located about 800 km south of Cario, it is150 km long and 20-80 km wide covering about 3,000 km2

Al Jaghbub - Located in northeastern Libya west of the Egyptian Siwa Oasis. The oasis supports a town of the same name.

Waw an Namus (Oasis of Mosquitos) - Located in southern Libya and in the very heart of the Sahara Desert, this remote oasis lies in the caldera of a volcano. The caldera is 4 km wide and 100 m deep with a central cone around which three small salt lakes occur.

Kufra (or Al Khufrah) Oasis - Located within the Kufra Basin in southeastern Libya, Kufra is about 50 km long and 20 km wide and containing several salt lakes.

Pumping of water from the underlying Nubian Sandstone Aquifer System supports one of Libya’s largest agricultural projects. The center-pivot irrigation system pumps water under pressure into a gantry or tubular arm from a central source. Anchored by a central pivot, the gantry slowly rotates over the area to be irrigated, thereby producing the circular patterns. Although the field diameters vary, these fields are approximately 0.6 mile (1 kilometer) in diameter. Darker colors indicate fields where such crops as wheat and alfalfa are grown. Lighter colors can indicate a variety of agricultural processes: fields that have been harvested recently; fields that are lying fallow; fields that have just been planted; or fields that have been taken out of production. The Astronaut photograph right was acquired October 28, 2004.

Gilf Kebir Plateau

Gilf Kebir (Great Barrier) is an elevated region of limestone and sandstone covering 7,770 km2 in the south west corner of Egypt, similar in structure to the other sandstone plateaus of the central Sahara. It rises about 300 metres above the surrounding desert to an altitude of 1,150 metres above sea level.

Gilf Kebir contains by many large valleys known as wadis created when the region had considerably more water than it does today.  These wadis often indicate rivers flowing out of the plateau into the surrounding areas in late late tertiary era. The northern part is more broken and supports three large wadis of which Wadi Hamra and Adb el Malik are the most distinctive.  South of the Gilf Kebir is the Uweinat mountain range which extends to Libya and Sudan.

There is limited vegetation. The area is noteworthy for its Neolithic artefacts and rock art such as the famed 'Cave of the Swimmers' located in Wasi Sora in the northwestern part of Gilf Kebir.

The Gilf Kebir National Park, created in 2007, covers 48.533 km2 and includes Gilf Kebir Plateau, the Beb el Uweinat massif (to the south), and the Great Sand Sea (to the north).

Sand Seas

Sand seas, also called "ergs" after the Arabic name for dune fields, are regional accumulations of windblown sand that contain numerous, very large dunes that resemble the waves of a sea. Dunes are of compound or complex form. Compound dunes are mounds or ridges on which smaller dunes of similar type and slip face orientation are superposed; these "two-story" dunes tend to be very large, measured in hundreds to thousands of meters in width or length, and some are as high as 400 m. Complex dunes are combinations of two or more dune types, and may be small, if coalesced, or large, two-story constructs like compound dunes, if superposed. Individual dunes in sand seas typically have widths, lengths, or both dimensions greater than 500 m. Both the regional extent of their sand cover and the complexity and great size of their dunes distinguish sand seas from dune fields. The latter features are of local extent and contain dunes that are smaller and simpler in form. The term sand sea is applied only to areas where sand covers more than 20 percent of the surface. In both sand seas and dune fields, ridges or mounds of sand are repeated in rows that give the surface a wavy appearance. Sand seas in the Libyan Desert are:

  • Great Sand Sea/Calanshio Sand Sea covers more than 100,000 km2 in western Egypt (Great Sand Sea) extending into eastern Libya (Calanshio Sand Sea). Three quarters of its area is covered by large sand dunes which run approximately north-south. The Siwa oasis lies to the north on the Egyptian side with the Qattara depression beyond  Siwa. The Gilf Kebir  plateau lies to the south. The area receives less than 5 mm of rain per year and thus is extremely arid and thus wind is the dominant factor shaping the landscape.
     
  • Rebiana Sand Sea covers a large area of southeast Libya. It is sometime considered an southerly extension of the Calanshio Sand Sea.

Ecology

The northern part of the Libyan Desert is included within the North Saharan steppe and woodlands ecoregion. This ecoregion forms the north and western border of the greater Sahara Desert region. Rainfall occurs during the cooler winter, nourishing a variety of plants that flower before the hot, dry summer. Compared to the South Saharan Steppe and Woodland, this ecoregion harbors a significant number of plant and small animal endemics. In the past the ecoregion also supported large numbers of desert-adapted African mammals, but many have been extirpated from the area due to decades (in some cases centuries) of over-hunting. Some of the remaining desert adapted species, such as the Dama gazelle and Houbara and Nubian bustards are still facing extreme hunting pressure, and in some areas they too have been extirpated.

The southern part of the Libyan Desert is included within the main Sahara Desert ecoregion. The ecoregion includes the hyper-arid central portion of the Sahara where rainfall is minimal and sporadic. Although species richness and endemism are low, some highly adapted species do survive with notable adaptations. Only a few thousand years ago the Sahara was significantly wetter, and a significant large mammal fauna resided in this area. Climatic desiccation over the past 5000 years, and intense human hunting over the past 100 years, has obliterated most of these fauna. Now, in vast portions of the Sahara, merely rock, sand and sparse vegetation are found. The remnant large mammal fauna is highly threatened by ongoing over-hunting.

The depresssions are included within the Saharan halophytics ecoregion. The habitats of this ecoregion are not particularly threatened, as human populations are very small and most of the areas are too saline to be used for farming. Large mammals, however, have been hunted out from these areas. Woody resources, where available, are used by desert people. The only permanently populated part of the ecoregion is the Siwa Oasis in Egypt, which has permanent freshwater sources from large springs. In the Qattara Depression, there are saline marshes under the northwestern and northern escarpment edges, and extensive playas that flood occasionally. Moghra oasis, the one oasis in the depression, is uninhabited and has a 4 km2 brackish lake, including Phragmites swamp. Salt marshes also occur and occupy approximately 300 km2, although in some areas, wind blown sands are encroaching. About one-quarter (26 percent) of the 19,500 km2 area is occupied by playas, which are comprised of hard crust and sticky mud, and which are occasionally filled with water.

History

In this map of Africa from Sebastian Münster's Cosmographia (1545), the Libyan desert (marked Libyae desertum and Libya Interior) is shown in the center of the continent, west of Nubiae regnum, south of Regnum Tunis and east of Regnum Senegae.

Before modern times, Sahara was traversed by mostly Muslim traders, natives and pilgrims of which the best known is Ibn Battuta.

The first European explorer to the Sahara was the German Friedrich Gerhard Rohlfs. In his expeditions beginning in 1865 he received much resistance from the natives of the Saharan oases and kingdoms he visited. Because of the resistance offered to all European explorers at the time, especially by Senussis Ikhwan, Rohlfs, who named the Great Sand Sea, only managed to come back with a few important findings which included an inaccurate first map of the Libyan Desert.

It was not until 1924, when Ahmed Hassanein undertook a 3,500 km (2,200 mi) expedition with a camel caravan that the first accurate maps were drawn and the mountain of Jebel Uweinat with springs at its base was discovered. He wrote important accounts on the Senussi sect, explaining their lifestyle and ethics in his book The Lost Oases.

Ralph Bagnold greatly extended the knowledge of the area (as well as developing techniques still used today for driving cars in sand) with many journeys in the 1920s and 30s using Ford Model Ts.

In 1935, the famous French aviator Antoine de Saint Exupéry crashed in the northern Libyan Desert. After miraculously surviving, he and his plane's mechanic nearly died of thirst before being rescued by a nomad. This event is described in Exupery's book Wind, Sand, and Stars.

The wreck of the B-24 bomber Lady Be Good—discovered 200 km (120 mi) north of Kufra 15 years after it was reported missing during WWII—had a less happy ending. The crew bailed out believing they were over the sea, when their plane ran out of fuel, and they became lost. When they landed in the Libyan Desert they could feel a North Westerly breeze, thinking they were near the Mediterranean they headed into the wind hoping it would lead them to safety. However, they were more than 640 km inland from the Mediterranean, and slowly died from dehydration after covering 130 km with minimal water in a place so dry even the desert Bedouins refuse to enter.

Further reading

  • Almásy, L. and Lozach, J. 1936. Récentes explorations dans le Désert Libyque (1932–1936) (Recent explorations in the Libyan Desert, 1932–1936). Société royale de géographie d'Égypte, 97 p.
  • Almásy, L. 1942. Unbekannte Sahara mit flugzeug und auto in der Libyschen wüste (The unknown Sahara by airplane and auto in the Libyan Desert). Leipzig: F.A. Brockhaus, 215 p.
  • Atiya, F. 2004, Silent Desert 1: Bahariya and Farafra Oases, American University in Cairo Press, ISBN-10: 9771708872
  • Bagnold, R.A. 1931. Journeys in the Libyan Desert, 1929 and 1930. The Geographical Journal 78(1):13-39; (6):524-533.
  • Bagnold, R.A. 1933. A further journey through the Libyan Desert. The Geographical Journal 82(2):103-129; (3):211-213, 226-235.
  • Bagnold, R.A. 1935. Libyan Sands: travel in a dead world. London: Travel Book Club, 351 p.
  • Bagnold, R.A. 1939. A lost world refound. Scientific American 161(5, November):261-263.
  • Besler, H. 2009. The Great Sand Sea in Egypt: formation, dynamics and environmental change, Elsevier Science ISBN-10: 0444529411
  • Bye bye Net.com, Gilf (jelf ) Al Kabir
  • Desert Processes Working Group; Knowledge Sciences, Inc. Summary: Sand Seas/Ergs/Dune Fields, Army Geospatial Center
  • El-Sharawy, Gamel M. and Henri J. Dumont, The Fayum Depression and Its Lakes, in The Nile,edited by Henri J. Dumont,  Monographiae Biologicae, 2009, Volume 89, III, 95-124, DOI: 10.1007/978-1-4020-9726-3_6
  • Forbes, R. 1921. Secret of the Sahara: Kufara. New York: George H. Doran, 356 p.
  • Hassanein Bey, A.M. 1924. Crossing the untraversed Libyan Desert. The National Geographic Magazine 46(3):233-277.
  • Hassanein Bey, A.M. 1925. The Lost Oases: Being a narrative account of the author's explorations into the more remote parts of the Libyan Desert and his rediscovery of two lost oases. 363 p.
  • Hoskins, G.A. 1837. Visit to the Great Oasis of the Libyan Desert. London, 341 p.
  • Hrdlicka, A. 2010, The natives of Kharga Oasis, Egypt, Nabu Press IBSN-10: 1177650606
  • Kjeilen, Tore Looklex report on the Qara oasis,
  • Mills, A. Dakhleh Oasis Project, Monash University
  • Minamar Hotel, Siwa Oasis
  • NASA, "Green Circles—Al Khufrah Oasis, Libya". NASA Earth Observatory.
  • Rohlfs G. 1875. Drei Monate in der Libyschen wüste (Three months in the Libyan Desert). Cassel: Verlag von Theodor Fischer, 340 p.
  • Sahara Safaris
  • Saint-Exupéry, A. de. 1939. Terre des homes (English title: Wind, Sand and Stars). Paris
  • Siliotti, A., 2010, Gilf Kebir National Park, American University in Cairo Press ISBN-10: 8887177848
  • Scholz, J.M.A. 1822. Travels in the countries between Alexandria and Parætonium, the Libyan Desert, Siwa, Egypt, Palestine, and Syria, in 1821. London, 120 p.
  • Scott, C. 2000. Sahara Overland: A route and planning guide‎. Trailblazer Publications, 544 p.
  • Smithsonian, Global Volcanism Program: Wau-en-Namus
  • St. John, B. 1849. Adventures in the Libyan Desert and the Oasis of Jupiter Ammon. London: John Murray, 244 p.
  • Zittel, K.A. von. 1875. Briefe aus der libyschen Wüste (Letters from the Libyan Desert). München.

Note: This article uses material from the Wikipedia article Libyan Desert that was accessed on July 27, 2011. The Author(s) and Topic Editor(s) associated with this article may have significantly modified the content derived from Wikipedia with original content or with content drawn from other sources. All content from Wikipedia has been reviewed and approved by those Author(s) and Topic Editor(s), and is subject to the same peer review process as other content in the EoE. The current version of the Wikipedia article may differ from the version that existed on the date of access. This article is dual-licensed under the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA) and the GNU Free Documentation License (GFDL) (unversioned, with no invariant sections, front-cover texts, or back-cover texts).. See the EoE Wikipedia Policy for more information.

Glossary

Citation

(2013). Libyan Desert. Retrieved from http://www.eoearth.org/view/article/168286

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