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Grand Erg Oriental
The Grand Erg Oriental (English: 'Great Eastern Sand Sea') is a large ''erg'' or "field of sand dunes" in the Sahara Desert. Situated for the most part in Saharan lowlands of northeast Algeria, the Grand Erg Oriental covers an area some 600 km wide by 200 km north to south. The erg's northeastern edge spills over into neighbouring Tunisia. Natural phenomena The Grand Erg Oriental is a desert, a natural region receiving very little rainfall. It is the largest ''Erg'' in Algeria, the next in size being the much smaller Grand Erg Occidental ('Western Sand Sea'). The largest erg of the Sahara is probably As-Sahra al-Libiyah, which straddles the inland border of Libya and Egypt. Erg is a Tamachek Berber word, and also a geographic term of art. The Grand Erg Oriental used to be associated with the Wadi Igharghar, a mostly dry and buried river with a sizable network of tributaries which, should it possess any water, would flow north into the erg from the Ahaggar mountains of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erg (landform)
An erg (also sand sea or dune sea, or sand sheet if it lacks dunes) is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover. The word is derived from the Arabic word ''ʿarq'' (), meaning "dune field". Strictly speaking, an erg is defined as a desert area that contains more than of aeolian or wind-blown sand and where sand covers more than 20% of the surface. Smaller areas are known as "dune fields". The largest hot desert in the world, the Sahara, covers and contains several ergs, such as the Chech Erg and the Issaouane Erg in Algeria. Approximately 85% of all the Earth's mobile sand is found in ergs that are greater than . Ergs are also found on other celestial bodies, such as Venus, Mars, and Saturn's moon Titan. Description Ergs are concentrated in two broad belts between 20° to 40°N and 20° to 40°S latitudes, which include regions crossed by the dry, subsiding air of the trade winds. Active ergs are limited to regions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of Earth. The first recorded use of the word γεωγραφία was as a title of a book by Greek scholar Eratosthenes (276–194 BC). Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come to be. While geography is specific to Earth, many concepts can be applied more broadly to other celestial bodies in the field of planetary science. One such concept, the first law of geography, proposed by Waldo Tobler, is "everything is related to everything else, but near things are more related than distant things." Geography has been called "the world discipline" and "the bridge between the human and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chott
In geology, a chott, shott, or shatt (; ar, شط, šaṭṭ, lit=bank, coast) is a salt lake in Africa's Maghreb that stays dry for much of the year but receives some water in the winter. The elevation of a chott surface is controlled by the position of the water table and capillary fringe, with sediment deflation occurring when the water table falls and sediment accumulation occurring when the water table rises.Swezey, C.S., 2003, The role of climate in the creation and destruction of continental stratigraphic records: An example from the northern margin of the Sahara Desert, in Cecil, C.B., and Edgar, N.T., eds., Climate Controls on Stratigraphy: SEPM (Society for Sedimentary Geology) Special Publication 77, p. 207-225. They are formed—within variable shores—by the spring thaw from the Atlas mountain range, along with occasional rainwater or groundwater sources in the Sahara, such as the Bas Saharan Basin. Water sources The chotts of the Sahara are fed intermittently d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerba
Djerba (; ar, جربة, Jirba, ; it, Meninge, Girba), also transliterated as Jerba or Jarbah, is a Tunisian island and the largest island of North Africa at , in the Gulf of Gabès, off the coast of Tunisia. It had a population of 139,544 at the 2004 census, which rose to 163,726 at the 2014 census. Citing the long and unique history of its Jewish minority in Djerba, Tunisia has sought UNESCO World Heritage status protections for the island. History Legend has it that Djerba was the island of the lotus-eaters where Odysseus was stranded on his voyage through the Mediterranean Sea. The island was called ''Meninx'' ( grc, Μῆνιγξ) until the third century AD. Strabo writes that there was an altar of Odysseus. The island was controlled twice by the Norman Kingdom of Sicily: in 1135–1158 and in 1284–1333. During the second of these periods it was organised as a feudal lordship, with the following Lords of Jerba: * 1284–1305: Roger I * 1305–1307, and 1307–1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Djerid
el-Djerid, also al-Jarīd, ( ar, الجريد; Derja: ''Jerīd''; ) or more precisely the South Western Tunisia Region is a semi-desert natural region comprising three southern Tunisian Governorates, Gafsa, Kebili and Tozeur with adjacent parts of Algeria and Libya. Geography The region is characterised by bare pink hills with oases and several chotts (salt pans) such as Chott el Djerid in Tunisia. Economically the area is important for phosphate mining. Major towns include Gafsa and Tozeur. It remains the principal center of Ibāḍism in North Africa, with remaining Ibāḍī communities on Djerba in Tunisia, in the M'zab in Algeria, and in Jabal Nafusa in Libya. In medieval times, it often formed a politically separate entity under the control of Ibāḍī ''imams''. Location Jerid, Djerid'' or ''Bled el Djerid (Arabic : الجريد, literally "palm leaf"), is a semi-desert region situated in southwestern Tunisia, which extends to the contiguous areas of Algeria. In admini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artesian Aquifer
An artesian aquifer is a confined aquifer containing groundwater under positive pressure. An artesian aquifer has trapped water, surrounded by layers of impermeable rock or clay, which apply positive pressure to the water contained within the aquifer. If a well were to be sunk into an artesian aquifer, water in the well-pipe would rise to a height corresponding to the point where hydrostatic equilibrium is reached. A well drilled into such an aquifer is called an ''artesian well''. If water reaches the ground surface under the natural pressure of the aquifer, the well is termed a ''flowing artesian well''. Fossil water aquifers can also be artesian if they are under sufficient pressure from the surrounding rocks, similar to how many newly tapped oil wells are pressurized. From the previous statement, it can be inferred that not all aquifers are artesian (i.e., water table aquifers occur where the groundwater level at the top of the aquifer is at equilibrium with atmospher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aurès
, native_name_lang = , settlement_type = Natural region , image_skyline = Ras el Aïoun.jpg , image_alt = , image_caption = Landscape of the Aurès in Ras el Aïoun , image_flag = , flag_alt = , image_seal = , seal_alt = , image_shield = , shield_alt = , nickname = , motto = , image_map = Localisation aures.svg , map_alt = , map_caption = A map of northern Algeria showing the location of the Aurès region in red and the greater region in green , pushpin_map = , pushpin_label_position = , pushpin_map_alt = , pushpin_map_caption = , coordinates = , coor_pinpoint = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = Algeria , to a lesser extent Tunisia , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and it is not synonymous with environmentalism. Among other things, ecology is the study of: * The abundance, biomass, and distribution of organisms in the context of the environment * Life processes, antifragility, interactions, and adaptations * The movement of materials and energy through living communities * The successional development of ecosystems * Cooperation, competition, and predation within and between species * Patterns of biodiversity and its effect on ecosystem processes Ecology has practical applications in conservation biology, wetland management, natural resource managemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomads
A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the population of nomadic pastoral tribes slowly decreased, reaching an estimated 30–40 million nomads in the world . Nomadic hunting and gathering—following seasonally available wild plants and game—is by far the oldest human subsistence method. Pastoralists raise herds of domesticated livestock, driving or accompanying them in patterns that normally avoid depleting pastures beyond their ability to recover. Nomadism is also a lifestyle adapted to infertile regions such as steppe, tundra, or ice and sand, where mobility is the most efficient strategy for exploiting scarce resources. For example, many groups living in the tundra are reindeer herders and are semi-nomadic, following forage for their animals. Sometimes also described as "nomad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasturage
Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs (non-grass herbaceous plants). Pasture is typically grazed throughout the summer, in contrast to meadow which is ungrazed or used for grazing only after being mown to make hay for animal fodder. Pasture in a wider sense additionally includes rangelands, other unenclosed pastoral systems, and land types used by wild animals for grazing or browsing. Pasture lands in the narrow sense are distinguished from rangelands by being managed through more intensive agricultural practices of seeding, irrigation, and the use of fertilizers, while rangelands grow primarily native vegetation, managed with extensive practices like cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wadi
Wadi ( ar, وَادِي, wādī), alternatively ''wād'' ( ar, وَاد), North African Arabic Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet (ephemeral) riverbed that contains water only when heavy rain occurs. Etymology The term ' is very widely found in Arabic toponyms. Some Spanish toponyms are derived from Andalusian Arabic where ' was used to mean a permanent river, for example: Guadalcanal from ''wādī al-qanāl'' ( ar, وَادِي الْقَنَال, "river of refreshment stalls"), Guadalajara from ''wādī al-ḥijārah'' ( ar, وَادِي الْحِجَارَة, "river of stones"), or Guadalquivir, from ''al-wādī al-kabīr'' ( ar, اَلْوَادِي الْكَبِير, "the great river"). General morphology and processes Wadis are located on gently sloping, nearly flat parts of deserts; commonly they begin on the distal portions of alluvial fans and extend to inland sabkhas or dry lakes. In basin and r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined ''alluvion'' (the F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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