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Lacustrine Plain
A lacustrine plain or lake plain is a plain formed due to the past existence of a lake and its accompanying sedimentation, sediment accumulation. Lacustrine plains can be formed through one of three major mechanisms: glacial drainage, differential uplift, and inland lake creation and drainage. Lake plains can have various uses depending on where and how they form. Over time, in regions where a lake once existed, as water drains or evaporates from the lake, the deposited sediments are left behind, resulting in a level plain of land where the lake once existed. The soil of the plain may constitute fertile and productive farmland due to the previous accumulation of lacustrine sediments; in other cases, it may become a wetland or a desert. Background Lacustrine plains are plains formed when lakes filled with sediments are drained. There are several reasons why drainage might occur, but in all cases the water in the lake is lost, leaving behind a level land of sediments. The result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chad Basin
The Chad Basin is the largest endorheic basin in Africa, centered approximately on Lake Chad. It has no outlet to the sea and contains large areas of semi-arid desert and savanna. The drainage basin is approximately coterminous with the sedimentary basin of the same name, but extends further to the northeast and east. The basin spans four modern nations, including most of Chad and a large part of Niger, Nigeria and Cameroon. A combination of dams, increased irrigation, climate change, and reduced rainfall are causing water shortages. 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, West African Craton and Congo craton, Congo Craton, and formed about the same time as the Benue Trough. It covers an area of about . It merges into the Iullemmeden Basin to the west at the Dame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciolacustrine Deposits
Sediments deposited into lakes that have come from glaciers are called glaciolacustrine deposits. In some European geological traditions, the term limnoglacial is used. These lakes include ice margin lakes or other types formed from glacial erosion or deposition. Sediments in the bedload and suspended load are carried into lakes and deposited. The bedload is deposited at the lake margin while the suspended load is deposited all over the lake bed. Glaciolacustrine deposits commonly form varves, which are annually deposited layers of silt and clay, where silt is deposited during the summer, and clay during the winter. Bedload deposits Sediments carried in the bedload of a stream, mostly sands and gravels, are deposited in deltas that form at the edges of lakes. These deposits will only be found near the edges of the lake. Suspended deposits Sediments that are carried in the suspended load of a stream, commonly silts and clays, are transported into the lake in suspension or by cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Till Plain
Till plains are an extensive flat plain of glacial till that forms when a sheet of ice becomes detached from the main body of a glacier and melts in place, depositing the sediments it carried. Ground moraines are formed with melts out of the glacier in irregular heaps, forming rolling hills. Till plains are common in areas such as the Midwestern United States, due to multiple glaciation events that occurred in the Holocene epoch. During this period, the Laurentide Ice Sheet advanced and retreated during the Pleistocene epoch. Till plains formed by the Wisconsin glaciation cover much of the Midwest, including North Dakota, South Dakota, Indiana, Minnesota, Wisconsin, Iowa, Illinois, and northern Ohio (see Glacial till plains (Ohio)). Characteristics Till plains are large flat or gently sloping areas of land on which glacial till has been deposited from a melted glacier. In some areas, these depositions can be up to hundreds of feet thick. The morphology of the till plain is ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluvial Plain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge.Goudie, A. S., 2004, ''Encyclopedia of Geomorphology'', vol. 1. Routledge, New York. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because of regular flooding, floodplains frequently have high soil fertility since nutrients are deposited with the flood waters. This can encourage farming; some important agricultural regions, such as the Nile and Mississippi river basins, heavily exploit floodplains. Agricultural and urban regions have developed near or on floodplains to take advantage of the rich soil and freshwater. However, the risk of inundation has led to increasing efforts to control flooding. Formation Most floodplains are formed by deposition on the inside of river meanders and by overbank flow. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvial Plain
An alluvial plain is a plain (an essentially flat landform) created by the deposition of sediment over a long period by one or more rivers coming from highland regions, from which alluvial soil forms. A ''floodplain'' is part of the process, being the smaller area over which the rivers flood at a particular time. In contrast, the alluvial plain is the larger area representing the region over which the floodplains have shifted over geological time. As the highlands erode due to weathering and water flow, the sediment from the hills is transported to the lower plain. Various creeks will carry the water further to a river, lake, bay, or ocean. As the sediments are deposited during flood conditions in the floodplain of a creek, the elevation of the floodplain will be raised. As this reduces the channel floodwater capacity, the creek will, over time, seek new, lower paths, forming a meander (a curved path). The leftover higher locations, typically natural levees at the margins of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plain
In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or Highland, uplands. Plains are one of the major landforms on earth, being present on all continents and covering more than one-third of the world's land area. Plains in many areas are important for agriculture. There are various types of plains and biomes on them. Description A plain or flatland is a flat expanse of land with a layer of grass that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or Highland, uplands. Plains are one of the major landforms on earth, where they are present on all continents, and cover more than one-third of the world's land area. In a valley, a plain is enclosed on tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congo River
The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon River, Amazon and Ganges rivers. It is the world's deepest recorded river, with measured depths of around . The Congo–Lualaba River, Lualaba–Luvua River, Luvua–Luapula River, Luapula–Chambeshi River system has an overall length of , which makes it the world's ninth-List of rivers by length, longest river. The Chambeshi is a tributary of the Lualaba River, and ''Lualaba'' is the name of the Congo River upstream of Boyoma Falls, extending for . Measured along with the Lualaba, the main tributary, the Congo River has a total length of . It is the only major river to cross the equator twice. The Congo Basin has a total area of about , or 13% of the entire African landmass. Name The name ''Congo/Kongo'' originates from the Kingdom of Ko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llancanelo Lake
Llancanelo Lake (Spanish: ''Laguna de Llancanelo'') is a wetland with an area of 650 km2. It is located in the Malargüe Department in the south of Mendoza Province, Argentina, 75 km from the city of Malargüe, at 1,280 m above mean sea level, within the arid region near the Andes in the limit between the regions of Cuyo and Patagonia. Llancanelo Lake is a provincial nature reserve. It hosts a variety of bird species, including flamingos, black-necked swans, herons and ducks. The lake is also a Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ... site (RS #759) since 8 November 1995. References Laguna de Llancanelo— Information sheet on Ramsar Wetlands. *Laguna de Llancaneloat PatrimonioNatural.com. Lakes of Mendoza Province Ramsar sites in Argen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Plains
The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include the mixed grass prairie, the tallgrass prairie between the Great Lakes and Appalachian Plateau, and the Taiga Plains Ecozone, Taiga Plains and Boreal Plains Ecozone, Boreal Plains ecozones in Northern Canada. "Great Plains", or Western Plains, is also the ecoregion of the Great Plains or the western portion of the Great Plains, some of which in the farthest west is known as the High Plains. The Great Plains lie across both the Central United States and Western Canada, encompassing: *Most or all of the U.S. states of Kansas, Nebraska, and North Dakota, North and South Dakota; *Eastern parts of the U.S. states of Colorado, Montana, and Wyoming; *Parts of the U.S. states of New Mexico, Oklahoma, Texas; *Sometimes western parts of Iowa, Minnesot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Bonneville
Lake Bonneville was the largest Late Pleistocene paleolake in the Great Basin of western North America. It was a pluvial lake that formed in response to an increase in precipitation and a decrease in evaporation as a result of cooler temperatures. The lake covered much of what is now western Utah and at its highest level extended into present-day Idaho and Nevada. Many other hydrographically closed basins in the Great Basin contained expanded lakes during the Late Pleistocene, including Lake Lahontan in northwestern Nevada. Geologic description Shorelines of Lake Bonneville are visible above Salt Lake City along the western front of the Wasatch Mountains and on other mountains throughout the Bonneville basin.Gilbert, G.K., 1890. Lake Bonneville. U.S. Geological Survey Monograph 1. 438 pp. These shorelines appear as shelves or benches that protrude from the mountainside above the valley floor, are visible on the ground from long distances and on satellite images, and have both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspian Sea
The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, west of the broad steppe of Central Asia, south of the fertile plains of Southern Russia in Eastern Europe, and north of the mountainous Iranian Plateau. It covers a surface area of (excluding the highly saline lagoon of Garabogazköl to its east), an area approximately equal to that of Japan, with a volume of . It has a salinity of approximately 1.2% (12 g/L), about a third of the salinity of average seawater. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the southwest, Iran to the south, and Turkmenistan to the southeast. The name of the Caspian Sea is derived from the ancient Iranian peoples, Iranic Caspians, Caspi people. The sea stretches from north to south, with an average width of . Its gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
