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Sag (geology)
In geology a sag, or Trough (geology), trough, is a depressed, persistent, low area; the opposite of an arch, or ridge, a raised, persistent, high area. The terms sag and arch were used historically to describe very large features, for example, characterizing North America as two arches with a sag between them. Also, a sag is a former river bed which has been partially filled with debris from glacier, glaciation or other natural processes but which is still visible in the surface terrain. Sags formed by the former river beds of large rivers often become the valleys of smaller streams after a change of course by the main river. Examples of sags include the former continuations of the Grand River (South Dakota), Grand, Moreau River (South Dakota), Moreau, and White River (Missouri River), White rivers in South Dakota in the United States. Before the Last Glacial Period, last ice age, these rivers continued eastward past their current confluences with the present course of Missouri R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trough (geology)
In geology, a trough is a linear structural depression that extends laterally over a distance. Although it is less steep than a ''trench'', a trough can be a narrow basin or a geologic rift. These features often form at the rim of tectonic plates. There are various oceanic troughs on the ocean floors. Examples of oceanic troughs * Benue Trough * Cayman Trough * Hesperides Trough * Kings Trough * Mariana Trough * Nankai Trough * Northumberland Trough * Okinawa Trough in the East China Sea * Rockall Trough and others along the rift of the mid-oceanic ridge * Salton Trough * South Shetland Trough * Suakin TroughDinwiddie, Robert et al. (2008) ''Ocean: The World's Last Wilderness Revealed'', London, Dorling Kindersley, page 452. in the Red Sea * Timor Trough See also * Oceanic basin * Thalweg * Walker Lane The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ridge
A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, with the terrain dropping down on either side. The crest, if narrow, is also called a ridgeline. Limitations on the dimensions of a ridge are lacking. Its height above the surrounding terrain can vary from less than a meter to hundreds of meters. A ridge can be either depositional, erosional, tectonic, or a combination of these in origin and can consist of either bedrock, loose sediment, lava, or ice depending on its origin. A ridge can occur as either an isolated, independent feature or part of a larger geomorphological and/or structural feature. Frequently, a ridge can be further subdivided into smaller geomorphic or structural elements. Classification As in the case of landforms in general, there is a lack of any commonly agreed clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land“Glacier, N., Pronunciation.” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/7553486115. Accessed 25 Jan. 2025. and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand River (South Dakota)
The Grand River () is a tributary of the Missouri River in South Dakota in the United States. The length of the combined branch is 110 mi (177 km). With its longest fork, its length is approximately 200 mi (320 km). Variant names According to the Geographic Names Information System, it has also been known historically as: *Creek of the Rees *Marapa River *Palanat Palanata Wakpa Ree *Ree River *Riviere au Corn *We tar hoo River Course It is formed by the confluence of the North Fork (which rises in North Dakota) and the longer South Fork (which rises in South Dakota and passes through the town of Buffalo) in northwestern South Dakota near Shadehill in Perkins County, near several parcels of the Grand River National Grassland. Shadehill Reservoir is located at this confluence. It flows east, through the Standing Rock Sioux Reservation and joins the Missouri in Lake Oahe, approximately northwest of Mobridge. The lower of the river form an arm of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moreau River (South Dakota)
The Moreau River (Lakota: Hiŋháŋ Wakpá) a tributary of the Missouri River, approximately long, in South Dakota in the United States. Moreau River has the name of a pioneer trader. It rises in two forks in northwestern South Dakota, in the Badlands Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded."Badlands" in '' Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 47. They are characterized by steep slopes, ... of Butte County, South Dakota, Butte and Harding County, South Dakota, Harding Counties. The North Fork rises approximately northeast of Crow Buttes. The South Fork rises approximately west of the headwaters of the North Fork. The two forks flow ESE and unite near Zeona, South Dakota, Zeona in southern Perkins County, South Dakota, Perkins County. The combined stream flows east, past Usta, South Dakota, Usta, and across the Cheyenne River Indian Reservation, past Iron Lightning, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White River (Missouri River)
The White River is a Missouri River tributary that flows through the U.S. states of Nebraska and South Dakota. The name stems from the water's white-gray color, a function of eroded sand, clay, and volcanic ash carried by the river from its source near the Badlands. Draining a basin of about , about of which is in South Dakota, the stream flows through a region of sparsely populated hills, plateaus, and badlands. The White River rises in northwestern Nebraska, in the Pine Ridge escarpment north of Harrison, at an elevation of above sea level. It flows southeast then northeast past Fort Robinson and north of Crawford. It crosses into southwestern South Dakota and flows north across the Pine Ridge Indian Reservation, then northeast, receiving Wounded Knee Creek and flowing between units of Badlands National Park. It flows east-northeast and southeast at the northern edge of the reservation, forming the northern boundary of the reservation and the southern boundary of Buffa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux tribe, which comprises a large portion of the population—with nine Indian reservation, reservations in the state—and has historically dominated the territory. South Dakota is the List of U.S. states and territories by area, 17th-largest by area, the List of U.S. states and territories by population, fifth-least populous, and the List of U.S. states and territories by population density, fifth-least densely populated of the List of U.S. states, 50 United States. Pierre, South Dakota, Pierre is the List of capitals in the United States, state capital, and Sioux Falls, South Dakota, Sioux Falls, with a population of about 213,900, is South Dakota's List of cities in South Dakota, most populous city. The state is bisected by the Missouri Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missouri River
The Missouri River is a river in the Central United States, Central and Mountain states, Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Mountains of southwestern Montana, then flows east and south for before entering the Mississippi River north of St. Louis, Missouri. The river drains Semi-arid climate, semi-arid Drainage basin, watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces. Although a tributary of the Mississippi, the Missouri River is slightly longer and carries a comparable volume of water, though a fellow tributary (Ohio River) carries more water. When combined with the lower Mississippi River, it forms the List of rivers by length, world's fourth-longest river system. For over 12,000 years, people have depended on the Missouri River and its Tributary, tributaries as a source of sustena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plateau
In geology and physical geography, a plateau (; ; : plateaus or plateaux), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides have deep hills or escarpments. Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental. A few plateaus may have a small flat top while others have wider ones. Formation Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, plate tectonics movements, and erosion by water and glaciers. Volcanic Volcanic plateaus are produced by volcanic activity. They may be formed by upwelling of volcanic magma or extrusion of lava. The underlining mechanism in forming p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missouri Coteau
The Missouri Coteau, or Missouri Plateau, () is a large plateau that stretches along the eastern side of the valley of the Missouri River in central North Dakota and north-central South Dakota in the United States. In the Canadian provinces of Saskatchewan and Alberta this physiographic region is classified as the Uplands Missouri Coteau, which is a part of the Great Plains Province or Alberta Plateau Region, which extends across the southwest corner of the province of Saskatchewan as well as the southeast corner of the province of Alberta. Historically, in Canada the area was known as the Palliser's Triangle and regarded as an extension of the Great American Desert and unsuitable for agriculture and thus designated by Canadian geographer and explorer John Palliser. The terrain of the Missouri Coteau features low hummocky, undulating, rolling hills, potholes, and grasslands. Apart from being a geographical area, the Missouri Coteau also has a cultural connection to the people of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
