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Erg Chebbi
Erg Chebbi () is one of Morocco's several ergs – large seas of dunes formed by wind-blown sand. It is located on the far western edge of the Sahara Desert. There are several other ergs in Morocco, such as Erg Chigaga near M'hamid. Description In places, the dunes of Erg Chebbi rise to 150 meters from the surrounding hamada (rocky desert) and altogether span an area of approximately 28 kilometers from north to south and 5–7 kilometers from east to west lining the Algerian border. The nearest sizable town is Erfoud, about 60 kilometers further north. One other city is Rissani, around 40 kilometers from Merzouga. Rissani was the site of a kingdom known as Sijilmassa, which became prosperous from the 8th to the 14th century due to its control of the caravan routes. Although rainfall is not very common, in 2006 flooding adjacent to the dunes destroyed many buildings and killed three people. Tourism Merzouga, the local tourist center, is located on the western lee of the d ... [...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 language, Arabic word ''ʿirq'' (), meaning "dune field". Strictly speaking, an erg is defined as a desert area that contains more than of aeolian processes, 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 , the largest being the Rub' al Khali, the ''Empty Quarter'' of the Arabian Peninsula. Ergs are also found on other celestial bodies, such as Venus, Mars, and Saturn's moon Titan (moon), Titan. Geography Sand seas and dune fields generally occur in regions downwind of copious sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sijilmasa
Sijilmasa (; also transliterated Sijilmassa, Sidjilmasa, Sidjilmassa and Sigilmassa) was a medieval Moroccan city and trade entrepôt at the northern edge of the Sahara in Morocco. The ruins of the town extend for five miles along the River Ziz in the Tafilalt oasis near the town of Rissani. The town's history was marked by several successive invasions by Berber dynasties. Up until the 14th century, as the northern terminus for the western trans-Sahara trade route, it was one of the most important trade centres in the Maghreb during the Middle Ages. History Foundation and early Middle Ages According to al-Bakri's ''Book of Routes and Places'', Sufrite Kharijites first settled the town in the wake of the Berber revolts against the Umayyads. Al-Bakri recounts that others joined these early settlers there, until they numbered around four thousand, at which point they laid the groundwork for the city. They elected a leader, 'Isa bin Mazid al-Aswad (the Black), to handle their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deserts Of Algeria
A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or Semi-arid climate, semi-arid. This includes much of the Polar regions of Earth, polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night strain the Rock (geology), rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landforms Of Morocco
A landform is a land feature on the solid surface of the Earth or other planetary body. They may be natural or may be anthropogenic (caused or influenced by human activity). Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great oceanic basins. Physical characteristics Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, structure stratification, rock exposure, and soil type. Gross physical features or landforms include intuitive elements such as berms, cliffs, hills, mounds, peninsulas, ridges, rivers, valleys, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ergs Of Africa
The erg is a unit of energy equal to 10−7joules (100 nJ). It is not an SI unit, instead originating from the centimetre–gram–second system of units (CGS). Its name is derived from (), a Greek word meaning 'work' or 'task'. An erg is the amount of work done by a force of one dyne exerted for a distance of one centimetre. In the CGS base units, it is equal to one gram centimetre-squared per second-squared (g⋅cm2/s2). It is thus equal to 10−7 joules or 100 nanojoules ( nJ) in SI units. * 1 erg = = * 1 erg = = = * 1 erg = = * 1 erg = = * 1 erg = History In 1864, Rudolf Clausius proposed the Greek word () for the unit of energy, work and heat. In 1873, a committee of the British Association for the Advancement of Science, including British physicists James Clerk Maxwell and William Thomson recommended the general adoption of the centimetre, the gramme, and the second as fundamental units ( C.G.S. System of Units). To distinguish derived units, they recommende ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Ergs
In geomorphology, an erg is a large desert region of sand dunes with little or no vegetation. It is divided into 3 parts: back erg, central erg, fore erg, especially in the Sahara. This is a list of ergs around the world. Africa ;Algeria * Grand Erg Oriental (extends into Tunisia) * Grand Erg Occidental (extends into Morocco) * Erg Chech (extends into Mali) * Erg Iguidi (extends into Mauritania) * Erg Issaouane * Erg er-Raoui * Erg Tiferine * Erg Tidohaine * Erg Merhiti * Erg Admer ; Botswana * Kalahari Desert ; Chad * Erg Djourab * Erg Idrisi ; Egypt * Black Desert * Erg Abunugar * Erg Abu Muharrik * Erg Abu Ramada * Gilf Kebir * Ramla el Kebir * Erg Somaya * Negev Desert (extends into Israel) * Great Sand Sea Desert * White Desert ; Libya * Erg Awbari * Erg Ubari * Erg Titersine * Erg Idehan Murzuq * Erg Ouan Kasa * Erg Tannezouft * Erg Takarkouri * Erg Mehedjibat * Erg Tassegefit * Calanshio Sand Sea * Rebiana Sand Sea ; Mali * Erg Achaif * Erg Aoukar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blowout (geology)
Blowouts are sandy depressions in a sand dune ecosystem (psammosere) caused by the removal of sediments by wind. Commonly found in coastal settings and margins of arid areas, blowouts tend to form when wind erodes patches of bare sand on stabilized vegetated dunes. Generally, blowouts do not form on actively flowing dunes because the dunes need to be bound to some extent, for instance by plant roots. These depressions usually start on the higher parts of stabilized dunes on account of the more considerable desiccation and disturbances occurring there, which allows for greater surface drag and sediment entrainment when the sand is bare. Most of the time, exposed areas become quickly re-vegetated before they can become blowouts and expand; however, when circumstances are favourable, wind erosion can gouge the exposed surface and create a tunneling effect which increases local wind speed. A depression may then develop until it hits a non-erodible substrate, or morphology limits it. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeolian Processes
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erosion, erode, transport, and deposit materials. They are effective agents in regions with sparse vegetation, a lack of soil moisture and a large supply of unconsolidated sediments. Although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts. The term is derived from the name of the Greek god Aeolus#Aeolus (son of Hippotes), Aeolus, the keeper of the winds. Definition and setting ''Aeolian processes'' are those processes of erosion, Sediment transport, transport, and Deposition (geology), deposition of sediments that are caused by wind at or near the surface of the earth. Sediment deposits produced by the action of wind and the sedimentary structures characteristic of these deposits are also described as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheumatism
Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including arthritis and "non-articular rheumatism", also known as "regional pain syndrome" or "soft tissue rheumatism". There is a close overlap between the term soft tissue disorder and rheumatism. Sometimes the term "soft tissue rheumatic disorders" is used to describe these conditions. The term "Rheumatic Diseases" is used in MeSH to refer to connective tissue disorders. The branch of medicine devoted to the diagnosis and therapy of rheumatism is called rheumatology. Types Many rheumatic disorders of chronic, intermittent pain (including joint pain, neck pain or back pain) have historically been caused by infectious diseases. Their etiology was unknown until the 20th century and not treatable. Postinfectious arthritis, also known as react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merzouga
Merzouga (, ) is a village in southeastern Morocco. The village is near the Erg Chebbi dunes, one of the tallest in the Sahara. It is about southeast of Rissani, about from Erfoud and about from the Algeria–Morocco border, Algerian border. Some of the other villages near the dunes are Hassilabied ( away), Tanamoust ( away), Takoujt ( away), Khamlia ( away), and Tisserdmine ( away). Rissani is the closest city of significant size, at 41.9 km away. (26 mi). History Approximately 9,000 to 10,000 years ago, the region was likely a tropical jungle, coinciding with a period when the Sahara Desert was characterized by abundant vegetation and Lake, lakes. Merzouga was an uninhabited oasis that later became a transit point for merchants heading to Timbuktu. It also became a pilgrimage destination for the nomads of the Aït Atta, Ait Atta tribes and eventually a tourist destination. During French Protectorate in Morocco, French colonial rule, fortifications were built by troops of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morocco
Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocco border, the east, and the disputed territory of Western Sahara to Morocco–Western Sahara border, the south. Morocco also claims the Spain, Spanish Enclave and exclave, exclaves of Ceuta, Melilla and Peñón de Vélez de la Gomera, and several small Plazas de soberanía, Spanish-controlled islands off its coast. It has a population of approximately 37 million. Islam is both the official and predominant religion, while Arabic and Berber are the official languages. Additionally, French and the Moroccan dialect of Arabic are widely spoken. The culture of Morocco is a mix of Arab culture, Arab, Berbers, Berber, Culture of Africa, African and Culture of Europe, European cultures. Its capital is Rabat, while its largest city is Casablanca. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
