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Lake Chad
Lake Chad (, Kanuri language, Kanuri: ''Sádǝ'', ) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon in western and central Africa respectively, with a catchment area of . It is an important wetland ecosystem in West-Central Africa. The lakeside is rich in reeds and swamps, and the plain along the lake is fertile, making it an important irrigated agricultural area. The lake is rich in aquatic resources and is one of the important freshwater fish producing areas in Africa. Lake Chad is divided into deeper southern parts and shallower northern parts. The water source of the lake mainly comes from rivers such as the Chari River that enter the lake. The water level varies greatly seasonally, and the area of the lake also changes dramatically. During the African humid period, the area of Lake Chad reached . Due to the increasingly arid climate, the lake surface gradually shrank. In the 19th century, Lake Chad still had an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sahel
The Sahel (; ar, ساحل ' , "coast, shore") is a region in North Africa. It is defined as the ecoclimatic and biogeographic realm of transition between the Sahara to the north and the Sudanian savanna to the south. Having a hot semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea. The Sahel part of Africa includes – from west to east – parts of northern Senegal, southern Mauritania, central Mali, northern Burkina Faso, the extreme south of Algeria, Niger, the extreme north of Nigeria, Cameroon and Central African Republic, central Chad, central and southern Sudan, the extreme north of South Sudan, Eritrea and Ethiopia. Historically, the western part of the Sahel was sometimes known as the Sudan region (''bilād as-sūdān'' "lands of the Sudan"). This belt was located between the Sahara and the coastal areas of West Africa. There are frequent shortages of food and water due to the dry h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kanuri Language
Kanuri () is a dialect continuum spoken in Nigeria, Niger, Chad and Cameroon, as well as in small minorities in southern Libya and by a diaspora in Sudan. Background At the turn of the 21st century, its two main dialects, Manga Kanuri and Yerwa Kanuri (also called Beriberi, which its speakers consider to be pejorative), were spoken by 9,700,000 people in Central Africa. It belongs to the Western Saharan subphylum of Nilo-Saharan. Kanuri is the language associated with the Kanem and Bornu empires that dominated the Lake Chad region for a thousand years. The basic word order of Kanuri sentences is subject–object–verb. It is typologically unusual in simultaneously having postpositions and post-nominal modifiers – for example, "Bintu's pot" would be expressed as ''nje Bintu-be'', "pot Bintu-of". Kanuri has three tones: high, low, and falling. It has an extensive system of consonantal lenition; for example, "they" + "have eaten" → "they have eaten". Traditionally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mayo Kébbi
The Mayo Kébbi is a river in Central and West Africa. The river rises in Chad, then flows west into the Bénoué River. Mayo-Kébbi Prefecture in Chad is named for it. The Mayo Kébbi is the major outlet for Lake Fianga, shared between Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ... and Chad. In the past, the Mayo Kébbi served as the outlet of the paleolake Mega-Chad.Leblanc et al. (2006). "Reconstruction of megalake Chad using shuttle radar topographic mission data". ''Palaeogeography, palaeoclimatology, palaeoecology'' 239, pp. 16–27 1872-616X The presence of African manatees in the inflows of Lake Chad is evidence of this, since the manatee is otherwise only in rivers connected to the Atlantic Ocean (i.e. it is not possible that it evolved separately in an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benue River
The Benue River (french: la Bénoué), previously known as the Chadda River or Tchadda, is the major tributary of the Niger River. The river is approximately long and is almost entirely navigable during the summer months. The size of its basin is . As a result, it is an important transportation route in the regions through which it flows. Geography It rises in the Adamawa Plateau of northern Cameroon, from where it flows west, and through the town of Garoua and Lagdo Reservoir, into Nigeria south of the Mandara mountains, and through Jimeta, Ibi and Makurdi before meeting the Niger River at Lokoja. Large tributaries are the Faro River, the Gongola River and the Mayo Kébbi, which connects it with the Logone River (part of the Lake Chad system) during floods. Other tributaries are Taraba River and River Katsina Ala. At the point of confluence, the Benue exceeds the Niger by volume. The mean discharge before 1960 was for the Benue and for the Niger. During the following ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacustrine Deposits
Lacustrine deposits are sedimentary rock formations which formed in the bottom of ancient lakes. A common characteristic of lacustrine deposits is that a river or stream channel has carried sediment into the basin. Lacustrine deposits form in all lake types including rift graben lakes, oxbow lakes, glacial lakes, and crater lakes. Lacustrine environments, like seas, are large bodies of water. They share similar sedimentary deposits which are mainly composed of low-energy particle sizes. Lacustrine deposits are typically very well sorted with highly laminated beds of silts, clays, and occasionally carbonates. In regards to geologic time, lakes are temporary and once they no longer receive water, they dry up and leave a formation. Lake types Lacustrine deposits can form in every variety of basins found in nature. How each basin originates is where the distinction between lacustrine deposit types stem. Rift graben lakes are formed from crustal stretching also known as rifting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatomaceous Earth
Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to less than 1 mm, but typically 10 to 200 μm. Depending on the granularity, this powder can have an abrasive feel, similar to pumice powder, and has a low density as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80–90% silica, with 2–4% alumina (attributed mostly to clay minerals), and 0.5–2% iron oxide. Diatomaceous earth consists of the fossilized remains of diatoms, a type of hard-shelled microalgae. It is used as a filtration aid, mild abrasive in products including metal polishes and toothpaste, mechanical insecticide, absorbent for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eolianite
Eolianite or aeolianite is any rock formed by the lithification of sediment deposited by aeolian processes; that is, the wind. In common use, however, the term refers specifically to the most common form of eolianite: coastal limestone consisting of carbonate sediment of shallow marine biogenic origin, formed into coastal dunes by the wind, and subsequently lithified. It is also known as kurkar_in_the_Middle_East.html" ;"title="haron Horowitz. ''The Quaternary of ... in the Middle East">haron Horowitz. ''The Quaternary of ... in the Middle East, miliolite in India and Arabia, and grès dunaire in the eastern Mediterranean. eolianite has a hardness of 4.3 and is very dull. Streak is light brown. Description Sayles coined the term in 1931, when he described the dune-shaped hills of Bermuda, consisting of bioclastic grainstones. Thus, Bermuda is considered the type locality for carbonate eolianite facies, with clearly defined cross-bedding, foresets, and topsets. Deposition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Shield
The Western Ethiopian Shield is a small geological shield along the western border of Ethiopia. Its plutons were formed between 830 and 540 million years ago. See also *Craton *Platform *Basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ... * Platform basement References Cratons Geology of Africa Geology of Ethiopia {{Geology-stub lv:Arābijas-Nūbijas vairogs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chad Basin
The Chad Basin is the largest endorheic basin in Africa, centered on Lake Chad. It has no outlet to the sea and contains large areas of semi-arid desert and savanna. The drainage basin is roughly coterminous with the sedimentary basin of the same name, but extends further to the northeast and east. The basin spans eight countries, including most of Chad and a large part of Niger. The region has an ethnically diverse population of about 30 million people as of 2011, growing rapidly. A combination of dams, increased irrigation, climate change, and reduced rainfall are causing water shortages, contributing to terrorism and the rise of Boko Haram in the region. Lake Chad continues to shrink. Geology The geological basin, which is smaller than the drainage basin, is a Phanerozoic sedimentary basin formed during the plate divergence that opened the South Atlantic Ocean. The basin lies between the West African Craton and Congo Craton, and formed around the same time as the Benue Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
