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Landforms

Landform

A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. 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 ocean 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, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux, and plains are the four major types of landforms. Minor landforms include buttes, canyons, valleys, and basins. Tectonic plate movement under the Earth can create landforms by pushing up mountains and hills. == Hierarchy of classes == Oceans and continents exemplify the highest-order landforms. Landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders, saddles, foreslopes and backslopes. Some generic landform elements including: pits, peaks, channels, ridges, passes, pools and plains. Terrain (or relief) is the third or vertical dimension of land surface. Topography is the study of terrain, although the word is often used as a synonym for relief itself. When relief is described underwater, the term bathymetry is used. In cartography, many different techniques are used to describe relief, including contour lines and triangulated irregular networks. Elementary landforms (segments, facets, relief units) are the smallest homogeneous divisions of the land surface, at the given scale/resolution. These are areas with relatively homogeneous morphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales, ranging from a few hundred meters to hundreds of kilometers. Hence, the spatial distribution of landforms is often scale-dependent, as is the case for soils and geological strata. A number of factors, ranging from plate tectonics to erosion and deposition (also due to human activity), can generate and affect landforms. Biological factors can also influence landforms— for example, note the role of vegetation in the development of dune systems and salt marshes, and the work of corals and algae in the formation of coral reefs. Landforms do not include several man-made features, such as canals, ports and many harbors; and geographic features, such as deserts, forests, and grasslands. Many of the terms are not restricted to refer to features of the planet Earth, and can be used to describe surface features of other planets and similar objects in the Universe. Examples are mountains, hills, polar caps, and valleys, which are found on all of the terrestrial planets. The scientific study of landforms is known as geomorphology. In onomastic terminology, toponyms (geographical proper names) of individual landform objects (mountains, hills, valleys, etc.) are called oronyms. == Recent developments == Landforms may be extracted from a digital elevation model (DEM) using some automated techniques where the data has been gathered by modern satellites and stereoscopic aerial surveillance cameras. Until recently, compiling the data found in such data sets required time consuming and expensive techniques involving many man-hours. The most detailed DEMs available are measured directly using LIDAR techniques. == See also == == References == == Sources == Room, Adrian (1996). An Alphabetical Guide to the Language of Name Studies. Lanham and London: The Scarecrow Press. ISBN 9780810831698. == Further reading == Hargitai Hetal. (2015) Classification and Characterization of Planetary Landforms. In: Hargitai H (ed) Encyclopedia of Planetary Landforms. Springer. DOI 10.1007/978-1-4614-3134-3 https://link.springer.com/content/pdf/bbm%3A978-1-4614-3134-3%2F1.pdf Page D (2015) The Geology of Planetary Landforms. In: Hargitai H (ed) Encyclopedia of Planetary Landforms. Springer. == External links == Open-Geomorphometry Project

Landforms

Glossary of landforms

Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type. == Landforms by process == Landforms organized by the processes that create them. === Aeolian landforms === Aeolian landform – Landforms produced by action of the winds are formed by the wind and include: Dry lake – Basin or depression that formerly contained a standing surface water body Sandhill – Type of ecological community or xeric wildfire-maintained ecosystem Ventifact – Rock that has been eroded by wind-driven sand or ice crystals Yardang – Streamlined aeolian landform === Coastal and oceanic landforms === Coastal and oceanic landforms include: === Cryogenic landforms === === Erosion landforms === Landforms produced by erosion and weathering usually occur in coastal or fluvial environments, and many also appear under those headings. === Fluvial landforms === Fluvial – Processes associated with rivers and streamsPages displaying short descriptions of redirect targets landforms include: === Impact landforms === Landforms created by extraterrestrial impacts – Collision of two astronomical objects with measurable effects – include: === Lacustrine landforms === Lacustrine – associated with lakes – landforms include: === Mountain and glacial landforms === Mountain and glacial landform – Landform created by the action of glaciers – include: === Slope landforms === Slope landforms include: === Tectonic landforms === Landforms created by tectonic activity include: === Volcanic landforms === Volcanic landforms include: === Weathering landforms === Weathering landforms include: == Landforms by shape == === Positive landforms === === Depressions === === Flat landforms === == Landforms, alphabetic == == Further reading == Hargitai H., Kereszturi Á. (eds): Encyclopedia of Planetary Landforms. Springer. https://link.springer.com/referencework/10.1007/978-1-4614-3134-3 == See also == Geomorphology – Scientific study of landforms Types of bodies of water Ocean – Body of salt water covering the majority of Earth Sea – Large body of salt water

Landforms

Alcove (landform)

Alcoves is the geographical and geological term for a steep-sided hollow in the side of an exposed rock face or cliff of a homogeneous rock type, that was water eroded. They are created through weathering, erosion, dry granular flow, and stress. Another factor in the formation of alcoves is winds between mid to late summer that steepen at the edge which leads to the failure and shaping of sand deposition in certain areas. == Locations on Earth == === North Pole === Although alcoves are both found in the northern and southern hemisphere, more newly developed alcoves are in the northern hemisphere region. Around the North Pole, dune alcoves, dune furrows, and scarp avalanches can form. The mechanism dune furrows are formed are through cryo jets and many form at alluvial fans. Furrows are channels and although mostly small they can vary in size and everytime they form in the spring season. Furrows do not have a long lifetime as they are often blown away by strong summer winds. === South Pole === In comparison, the South Pole differs in having higher elevation which can cause changes in alcove formation. These differences include the South Pole having older alcoves due to its denser deposition craters which are approximately 2 to 3 m thick which include particles of ice and minerals, and craters that contains carbon dioxide ice. Both South Pole and North Pole alcoves are formed through stress cementing the sandstone particles together. So after erosion, at the area where the most rock has been excavated by weathering the pressure builds up and the sand particles become very stable and hold the arch above. == Locations on Other Planetary Bodies == === Mars === Annually in the North Pole region, alcove formation is most active during autumn and winter seasons and also form specific alcove-apron regions during springtime sublimation. This is when the alcoves start at the edge of dunes and deposit and end into an apron fan shape. During summertime on Mars, strong winds will blow away smaller less stable alcoves which starts the cycle for new alcoves to form the following autumn and winter. It is estimated that alcove formation is responsible for a range of 2 to 20% of sand movement on Mars. == References ==

Landforms

Alder carr

An alder carr is a particular type of carr, i.e. waterlogged wooded terrain populated with alder trees. == Examples == Alder Carr, Hildersham Alderfen Broad Fawley Ford on the Beaulieu River Biebrza National Park Fen Alder Carr Harston Wood Holywells Park, Ipswich: Pond 5 is known as Alder Carr and is a biodiversity action plan habitat. Historically there was another Alder Carr in the Cobbold family estate in what is now the northern edge of the Landseer Park. Jackson's Coppice and Marsh Loynton Moss == Gallery == == References ==

Landforms

Alvar

An alvar is a biological environment based on a limestone plain with thin or no soil and, as a result, sparse grassland vegetation. Often flooded in the spring, and affected by drought in midsummer, alvars support a distinctive group of prairie-like plants. Most alvars occur either in northern Europe or around the Great Lakes in North America. This stressed habitat supports a community of rare plants and animals, including species more commonly found on prairie grasslands. Lichen and mosses are common species. Trees and bushes are absent or severely stunted. The primary cause of alvars is the shallow exposed bedrock. Flooding and drought, as noted, add to the stress of the site and prevent many species from growing. Disturbance may also play a role. In Europe, grazing is frequent, while in North America, there is some evidence that fire may also prevent encroachment by forest. The habitat also has strong competition gradients, with better competitors occupying the deeper soil and excluding other species to less productive locations. Crevices in the limestone provide a distinctive habitat which is somewhat protected from grazing, and which may provide habitat for unusual ferns such as Pellaea atropurpurea. Bare rock flats provide areas with extremely low competition that serve as refugia for weak competitors such as the sandwort Minuartia michauxii and Micranthes virginiensis. In a representative set of four Ontario alvars, seven habitat types were described. From deep to shallow soil these were: tall grassy meadows, tall forb-rich meadows, low grassy meadows, low forb-rich meadows, dry grassland, rock margin grassland and bare rock flats.Alvars comprise a small percentage of the Earth's ecosystems by land extent. Although some 120 exist in the Great Lakes region, in total there are only about 43 sq mi (110 km2) left across the entire Great Lakes basin, and many of these have been degraded by agriculture and other human uses. More than half of all remaining alvars occur in Ontario. There are smaller areas in New York, Michigan, Ohio, Wisconsin and Quebec.In North America, alvars provide habitat for birds such as bobolinks, eastern meadowlarks, upland sandpipers, eastern towhees, brown thrashers and loggerhead shrikes whose habitat is declining elsewhere. Rare plants include Kalm's lobelia (Lobelia kalmii), Pringle's aster (Symphyotrichum pilosum var. pringlei), juniper sedge (Carex juniperorum), lakeside daisy (Hymenoxys acaulis), ram's-head lady's-slipper (Cypripedium arietinum), and dwarf lake iris (Iris lacustris). Also associated with alvars are rare butterflies and snails. The use of the word "alvar" to refer to this type of environment originated in Sweden. The largest alvar in Europe is located on the Swedish island of Öland. Here the thin soil mantle is only 0.5 to 2.0 centimeters thick in most places and in many extents consists of exposed limestone slabs. The landscape there has been designated a UNESCO World Heritage Site. There are other more local names for similar landforms, such as a pavement barren, although this term is also used for similar landforms based on sandstone. In the United Kingdom the exposed landform is called a limestone pavement and thinly covered limestone is known as calcareous grassland. == European alvar locations == Sweden Öland – Stora Alvaret – largest alvar extent in Europe Gotland Västergötland – several locations on limestone mountain Kinnekulle, smaller fragments on Falbygden, e.g. in Dala and Högstena parishes Estonia Alvars are distributed along the whole northern coast of Estonia from approx. the town of Paldiski to Sillamäe, wherever limestone comes to the surface near the seashore (see Baltic Klint), as well as on the islands of the West Estonian archipelago. Estonia used to be home to approximately one third of the world's alvars; however, the total area of alvars has decreased from 43,000 hectares in the 1930s to 12,000 hectares in 2000, and approximately 9,000 hectares in 2010. Estonian alvars are home to 267 species of vascular plants, approximately one fifth of which are protected. There are also 142 species of bryophytes and 263 species of lichens. The Estonian government has committed itself to protect at least 9,800 hectares of the country's alvars as part of the Natura 2000 network. The Loopealse subdistrict of Tallinn is named after alvar. Vardi Nature Reserve in Rapla County is an Estonian nature reserve especially designated to protect one of the more representative alvar areas of Estonia. England Cumbria and North Yorkshire – under protection in the UK Biodiversity Action Plan Ireland The Burren, a large alvar in northwest County Clare == Some North American alvar locations == The rare Charitable Research Reserve – Cambridge, Ontario Lake Erie Kelley's Island, Ohio – North Shore Alvar State Nature Preserve Marblehead, Ohio – mostly destroyed by limestone quarrying Pelee Island, Ontario – Stone Road Alvar Nature Reserve Lake Huron Maxton Plains Proposed Natural Area, Drummond Island, Michigan Belanger Bay Alvar, Manitoulin Island, Ontario Quarry Bay Nature Reserve, Manitoulin Island, Ontario Bruce Alvar Nature Reserve, Bruce Peninsula, Ontario Baptise Harbour Nature Reserve, Bruce Peninsula, Ontario Misery Bay Provincial Park, Manitoulin Island, Ontario Lake Michigan Red Banks Alvar, Red Banks, Brown County, Wisconsin Lake Ontario Carden Plain Alvar, City of Kawartha Lakes, Ontario, including Carden Alvar Provincial Park Chaumont Barrens Preserve, New York Three Mile Creek Barrens, New York Burnt Lands Alvar, Almonte, Ontario Balsam Lake Indian Point Provincial Park, Ontario Quebec Quyon Alvar d'Aylmer Manitoba Interlake == See also == Calcareous grassland – An ecosystem associated with thin basic soil Chalk heath Edaphic – Science concerned with the influence of soils on living beingsPages displaying short descriptions of redirect targets Gypcrust – Hardened layer of soil with a high percentage of gypsum Gypsum flora of Nova Scotia – Group of plants in Nova Scotia, Canada Rendzina – Humus-rich shallow soil type Barren vegetation – Area of land where plant growth may be limited == References == == External links == Media related to Alvar at Wikimedia Commons http://www.epa.gov/ecopage/shore/alvars/

Landforms

Amba (landform)

An Amba (Amharic: ዐምባ āmbā, Tigrinya: እምባ imbā) is a characteristic landform in Ethiopia. It is a steep-sided, flat-topped mountain, often the site of villages, wells, and their surrounding farmland. Such settlements were frequently located on these amba plateaus because they were very defensible and often virtually inaccessible from the ground. The original term in Amharic indicates a mountain fortress. Amba Geshen, for example, is a historically significant amba where members of royal families were kept under guard for their safety and to prevent their participation in plots against the sitting emperor. Other noted Ambas include Amba Aradam and Amba Alagi, sites of famous battles during the first and second Italo-Ethiopian Wars. == Notable Ambas in Ethiopian History == Amba Geshen - A Historic 'Prison' or 'Detention' location for royal family members. Debre Damo - The name of both an Amba and historic Ethiopian Church. Magdala - Emperor Tewodros's capitol before his death during the British Expedition to Abyssinia. Amba Alagi - Site of 3 Battles, in both Italo-Ethiopian Wars. == More Recent Information Regarding Ambas == In 2008, a scientific mission identified on an amba near Harar, the Kundudo, one of just two feral horse populations in Africa. == See also == Hillfort Mesa == References == == Sources == Munro-Hay, Stuart, Ethiopia, the Unknown Land: A Cultural and Historical Guide, Contributor Pamala Taor, Published 2002 by I. B. Tauris, 384 pages, ISBN 1-86064-744-8

Landforms

Barachois

A barachois is a term used in Atlantic Canada, Saint Pierre and Miquelon, Réunion and Mauritius to describe a coastal lagoon partially or totally separated from the ocean by a sand or shingle bar. Sometimes the bar is constructed of boulders, as is the case at Freshwater Bay near St. John’s, Newfoundland. Salt water may enter the barachois during high tide. The bar often is formed as a result of sediment deposited in the delta region of a river or – as is the case in Miquelon – by a tombolo. == Name == The English term comes from the French language, where the word is pronounced [ba.ʁa.ʃwa]. The term comes from a Basque word, barratxoa, meaning little bar. The popular derivation from the French barre à choir is without historical merit. In Newfoundland English, the word has become pronounced as barshwa. == Examples == Dark Harbour, Grand Manan, New Brunswick (photo) Barachois de Malbaie on the tip of the Gaspé Peninsula, fed by one of two Malbaie Rivers in Quebec and the Beattie, du Portage, and Murphy Rivers Grand Barachois, Miquelon Island Grand-Barachois, in Westmorland County, New Brunswick Barachois Pond Provincial Park in western Newfoundland Big Barasway and Little Barasway, communities on Newfoundland's Cape Shore Prince Edward Island National Park has several examples Percival Bay, off the Northumberland Strait, is also known as the Big Barachois The coves in the lagoon of Diego Garcia in the Indian Ocean Topsail Beach Provincial Park, Topsail Former settlement of Freshwater, near St John's, Newfoundland. Great Barachois, near Petit-de-Grat, Nova Scotia == References ==

Landforms

Barrier range

Landforms

Barrier ridge

The terms barrier ridge, a term of art in the earth sciences, especially geology and sometimes barrier range (more common as a geography term) describing the existence of gross landforms describing long ridgelines which are particularly difficult to pass, especially in the context of being on foot or dependent upon other forms of animal powered transportation systems, in mountainous and sometimes hilly terrains. Barrier ridges such as the steep rising slopes or escarpments of the Allegheny Front, separating the ridge-and-valley Appalachians from the drainage divides of the uplands of the Appalachian Plateau. The ridge and valley region is filled with a succession of nearly impassible ridges from Northern Georgia, along the Appalachian chain all the way to Maine. == Notes == == References == == External links == Media related to Barrier ridge at Wikimedia Commons

Landforms

Basin and range topography

Basin and range topography is characterized by alternating parallel mountain ranges and valleys. It is a result of crustal extension due to mantle upwelling, gravitational collapse, crustal thickening, or relaxation of confining stresses. The extension results in the thinning and deformation of the upper crust, causing it to fracture and create a series of long parallel normal faults. This results in block faulting, where the blocks of rock between the normal faults either subside, uplift, or tilt. The movement of these blocks results in the alternating valleys and mountains. As the crust thins, it also allows heat from the mantle to more easily melt rock and form magma, resulting in increased volcanic activity. == Types of faulting == === Symmetrical faulting: horst and graben === With crustal extension, a series of normal faults which occur in groups, form in close proximity and dipping in opposite directions. As the crust extends it fractures in series of fault planes, some blocks sink down due to gravity, creating long linear valleys or basins also known as grabens, while the blocks remaining up or uplifted produce mountains or ranges, also known as horsts. Fault scarps are exposed on the horst block and expose the footwall of the normal fault. This is a type of block faulting known as grabens and horsts. This basin and range topography is symmetrical having equal slopes on both sides of the valleys and mountain ranges. === Asymmetric faulting: tilted block faulting === Tilted block faulting, also known as half-graben or rotational block faulting, can also occur during extension. Large gently dipping normal faults, also known as detachment faults, act as platforms in which normal faulted blocks tilt or slide along. However, instead of the whole block subsiding only one side, the block may slip along the detachment fault, tilting toward the fault plane, again creating mountains (ranges) and valleys (basins), many tilted slightly in one direction at their tops due to the motion of their bottoms along the main detachment fault. This basin and range topography has one steep side and the other is more gradual. == Examples == === Basin and Range Province === The Basin and Range Province is the most well known example of basin and range topography. Clarence Dutton compared the many narrow parallel mountain ranges that distinguish the unique topography of the Basin and Range to an "army of caterpillars crawling northward."The physiography of the province is the result of tectonic extension that began around 17 million years ago in the early Miocene epoch. Opinions vary regarding the total extension of the region; however, the median estimate is about 100% total lateral extension. The tectonic mechanisms responsible for lithospheric extension in the Basin and Range province are controversial, and several competing hypotheses attempt to explain them. === Aegean Sea Plate === The Aegean Sea Plate consists of thinned continental crust. The northern part of the plate is currently a region of crustal extension caused by slab rollback on the Hellenic Subduction Zone to the south, causing extensive normal faulting and the formation of horsts and grabens on the seafloor. Many of the islands are the result of peaks reaching above sea level. == Mapping extension == One of the most studied basin and range topographies is the Basin and Range Province in the western United States, located between the Sierra Nevada and the Rocky Mountains. The extension of the province was believed to have begun in the late Cenozoic Era, roughly 20 Ma. Between 1992 and 1998 scientists conducted GPS surveys to map the deformation of the Basin and Range province. In the study, Thatcher et al. discovered that most deformation was happening in the west, adjacent to the Sierra Nevada block, while less deformation was happening in the east. This coincides with the northwestward movement of the Sierra Nevada microplate.Though the Aegean Sea Plate is more difficult to study because it is underwater, efforts have been made to conduct GPS surveys of the seafloor and surrounding area. Some studies show regions of extension within the plate, while others suggest a four-microplate model to represent the motion. The plate's deformation is thought to be a result of crustal collapse (beginning c. 14 Ma) combined with slab rollback on the Hellenic Subduction Zone. == See also == Bolson Endorheic basin == References == == External links == Southern California Earthquake Data Center Glossary

Landforms

Bench (geology)

In geomorphology, geography and geology, a bench or benchland is a long, relatively narrow strip of relatively level or gently inclined land that is bounded by distinctly steeper slopes above and below it. Benches can be of different origins and created by very different geomorphic processes. First, the differential erosion of rocks or sediments of varying hardness and resistance to erosion can create benches. Earth scientists called such benches "structural benches." Second, other benches are narrow fluvial terraces created by the abandonment of a floodplain by a river or stream and entrenchment of the river valley into it. Finally, a bench is also the name of a narrow flat area often seen at the base of a sea cliff that was created by waves or other physical or chemical erosion near the shoreline. These benches are typically referred to as either "coastal benches," "wave-cut benches," or "wave-cut platforms."In mining, a bench is a narrow, strip of land cut into the side of an open-pit mine. These step-like zones are created along the walls of an open-pit mine for access and mining. == See also == Raised beach, also known as Marine terrace – Emergent coastal landform Piedmonttreppen Strandflat – Type of landform found in high-latitude areas Terrace (geology) – A step-like landform == References == == External links ==

Landforms

Bocage

Bocage (UK: , US: BOH-kahzh) is a terrain of mixed woodland and pasture characteristic of parts of northern France, southern England, Ireland, the Netherlands and northern Germany, in regions where pastoral farming is the dominant land use. Bocage may also refer to a small forest, a decorative element of leaves, or a type of rubble-work, comparable with the English use of "rustic" in relation to garden ornamentation. In the decorative arts, especially porcelain, it refers to a leafy screen spreading above and behind figures. Though found on continental figures, it is something of an English speciality, beginning in the mid-18th century, especially in Chelsea porcelain, and later spreading to more downmarket Staffordshire pottery figures. In English, bocage refers to a terrain of mixed woodland and pasture, with fields and winding country lanes sunken between narrow low ridges and banks surmounted by tall thick hedgerows that break the wind but also limit visibility. It is the sort of landscape found in many parts of southern England, for example the Devon hedge and Cornish hedge. However the term is more often found in technical than general usage in England. In France the term is in more general use, especially in Normandy, with a similar meaning. Bocage landscape in France is largely confined to Normandy, Brittany, and parts of the Loire valley. == Etymology == Bocage is a Norman word that comes from the Old Norman boscage (Anglo-Norman boscage, Old French boschage), from the Old French root bosc ("wood") > Modern French bois ("wood") cf. Medieval Latin boscus (first mentioned in 704 AD). The Norman place names retain it as Bosc-, -bosc, Bosc-, pronounced traditionally [bɔk] or [bo]. The suffix -age means "a general thing". The boscage form was used in English for "growing trees or shrubs; a thicket, grove; woody undergrowth" and to refer to decorative design imitating branches and foliage or leafy decoration such as is found on eighteenth-century porcelain; since early twentieth century this usually called "bocage". Similar words occur in Scandinavian (cf. Swedish buskage; Danish buskads) and other Germanic languages (cf. Dutch bos, boshaag); the original root is thought to be the Proto-Germanic *bŏsk-. The boscage form seems to have developed its meaning under the influence of eighteenth-century romanticism. The 1934 Nouveau Petit Larousse defined bocage as "a bosquet, a little wood, an agreeably shady wood" and a bosquet as "a little wood, a clump of trees". By 2006, the Petit Larousse definition had become "(Norman word) Region where the fields and meadows are enclosed by earth banks carrying hedges or rows of trees and where the habitation is generally dispersed in farms and hamlets." == Historic role == === England === In Southeast England, in spite of a sedimentary soil which would not fit this landscape, a bocage resulted from the movement of the enclosure of the open fields. During the 17th century, England developed an ambitious sea policy. One of the effects of this was the importation of Russian wheat, which was cheaper than English wheat at that time. The enclosures common in the bocage countryside favoured sheep husbandry and limited English cereal grain production, and as a consequence of this policy, the rural exodus was amplified, accelerating the Industrial Revolution. The surplus of agricultural workers migrated to the cities to work in factories. === Normandy === In Normandy, the bocage acquired a particular significance in the Chouannerie during the French Revolution.The bocage was also significant during the Battle of Normandy in World War II, as it made progress against the German defenders difficult. Plots of land were divided by ancient rows of dirt alongside irrigation ditches; thick vegetation on these dirt mounds could create walls up to sixteen feet high. A typical square mile on the battlefield might contain hundreds of irregular hedged enclosures. In response, "Rhino tanks" fitted with bocage-cutting modifications were developed. American personnel usually referred to bocage as hedgerows. The German army also used sunken lanes to implement strong points and defences to stop the American troops on the Cotentin Peninsula and around the town of Saint-Lô. === Ireland === Almost all of lowland Ireland is characterised by bocage landscape, a consequence of pastoral farming which requires enclosure for the management of herds. Approximately 5% of Ireland's land area is devoted to hedges, field walls and shelterbelts. In the more fertile areas these usually consist of earthen banks, which are planted with or colonised by trees and shrubs; this vegetation can give the impression of a wooded landscape, even where there is little or no woodland. This pattern of hedgerows was largely established in the late 18th and 19th centuries, a period when Ireland was virtually devoid of natural woodland. Modern intensive agriculture has tended to increase field size by removing hedgerows, a trend which for years was promoted by the Common Agricultural Policy of the European Union and recently has been countered by the European Union's agricultural policies favouring the conservation of wildlife habitats. == References == == Sources == Oxford English Dictionary Nouveau Petit Larousse Illustré (1934) Petit Larousse Illustré 2007 (2006) == External links == Media related to Boscages at Wikimedia Commons The dictionary definition of bocage at Wiktionary

Landforms

Bog

A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials – often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; alkaline mires are called fens. A baygall is another type of bog found in the forest of the Gulf Coast states in the United States. They are often covered in heath or heather shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink.Bogs occur where the water at the ground surface is acidic and low in nutrients. A bog usually is found at a freshwater soft spongy ground that is made up of decayed plant matter which is known as peat. They are generally found in cooler northern climates and are formed in poorly draining lake basins. In contrast to fens, they derive most of their water from precipitation rather than mineral-rich ground or surface water. Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate result in relatively slow plant growth, but decay is even slower due to low oxygen levels in saturated bog soils. Hence, peat accumulates. Large areas of the landscape can be covered many meters deep in peat.Bogs have distinctive assemblages of animal, fungal, and plant species, and are of high importance for biodiversity, particularly in landscapes that are otherwise settled and farmed. == Distribution and extent == Bogs are widely distributed in cold, temperate climes, mostly in boreal ecosystems in the Northern Hemisphere. The world's largest wetland is the peat bogs of the Western Siberian Lowlands in Russia, which cover more than a million square kilometres. Large peat bogs also occur in North America, particularly the Hudson Bay Lowland and the Mackenzie River Basin. They are less common in the Southern Hemisphere, with the largest being the Magellanic moorland, comprising some 44,000 square kilometres (17,000 sq mi) in southern South America. Sphagnum bogs were widespread in northern Europe but have often been cleared and drained for agriculture. A paper led by Graeme T. Swindles in 2019 showed that peatlands across Europe have undergone rapid drying in recent centuries owing to human impacts including drainage, peat cutting and burning. A 2014 expedition leaving from Itanga village, Republic of the Congo, discovered a peat bog "as big as England" which stretches into neighboring Democratic Republic of Congo. == Definition == Like all wetlands, it is difficult to rigidly define bogs for a number of reasons, including variations between bogs, the in-between nature of wetlands as an intermediate between terrestrial and aquatic ecosystems, and varying definitions between wetland classification systems. However, there are characteristics common to all bogs that provide a broad definition: Peat is present, usually thicker than 30 cm. The wetland receives most of its water and nutrients from precipitation (ombrotrophic) rather than surface or groundwater (minerotrophic). The wetland is nutrient-poor (oligotrophic). The wetland is strongly acidic (bogs near coastal areas may be less acidic due to sea spray).Because all bogs have peat, they are a type of peatland. As a peat-producing ecosystem, they are also classified as mires, along with fens. Bogs differ from fens in that fens receive water and nutrients from mineral-rich surface or groundwater, while bogs receive water and nutrients from precipitation. Because fens are supplied with mineral-rich water, they tend to be slightly acidic to slightly basic, while bogs are always acidic because precipitation is mineral-poor. == Ecology and protection == There are many highly specialized animals, fungi, and plants associated with bog habitat. Most are capable of tolerating the combination of low nutrient levels and waterlogging.: chapter 3  Sphagnum is generally abundant, along with ericaceous shrubs. The shrubs are often evergreen, which may assist in conservation of nutrients. In drier locations, evergreen trees can occur, in which case the bog blends into the surrounding expanses of boreal evergreen forest. Sedges are one of the more common herbaceous species. Carnivorous plants such as sundews (Drosera) and pitcher plants (for example Sarracenia purpurea) have adapted to the low-nutrient conditions by using invertebrates as a nutrient source. Orchids have adapted to these conditions through the use of mycorrhizal fungi to extract nutrients.: 88  Some shrubs such as Myrica gale (bog myrtle) have root nodules in which nitrogen fixation occurs, thereby providing another supplemental source of nitrogen. Bogs are recognized as a significant/specific habitat type by a number of governmental and conservation agencies. They can provide habitat for mammals, such as caribou, moose, and beavers, as well as for species of nesting shorebirds, such as Siberian cranes and yellowlegs. Bogs contain species of vulnerable reptilians such as the bog turtle. Bogs even have distinctive insects; English bogs give a home to a yellow fly called the hairy canary fly (Phaonia jaroschewskii), and bogs in North America are habitat for a butterfly called the bog copper (Lycaena epixanthe). In Ireland, the viviparous lizard, the only known reptile in the country, dwells in bogland.The United Kingdom in its Biodiversity Action Plan establishes bog habitats as a priority for conservation. Russia has a large reserve system in the West Siberian Lowland. The highest protected status occurs in Zapovedniks (IUCN category IV); Gydansky and Yugansky are two prominent examples.Bogs are fragile ecosystems, and have been deteriorating quickly, as archaeologists and scientists have been recently finding. Bone material found in bogs has had accelerated deterioration from first analyses in the 1940s. This has been found to be from fluctuations in ground water and increase in acidity in lower areas of bogs that is affecting the rich organic material. Many of these areas have been permeated to the lowest levels with oxygen, which dries and cracks layers. There have been some temporary solutions to try and fix these issues, such as adding soil to the tops of threatened areas, yet they do not work in the long-term. Extreme weather like dry summers are likely the cause, as they lower precipitation and the groundwater table. It is speculated that these issues will only increase with a rise in global temperature and climate change. Since bogs take thousands of years to form and create the rich peat that is used as a resource, once they are gone they are extremely hard to recover. Arctic and sub-Arctic circles where many bogs are warming at 0.6 °C per decade, an amount twice as large as the global average. Because bogs and other peatlands are carbon sinks, they are releasing large amounts of greenhouse gases as they warm up. These changes have resulted in a severe decline of biodiversity and species populations of peatlands throughout Northern Europe. == Types == Bog habitats may develop in various situations, depending on the climate and topography (see also hydrosere succession). === By location and water source === Bogs may be classified on their topography, proximity to water, method of recharge, and nutrient accumulation . ==== Valley bog ==== These develop in gently sloping valleys or hollows. A layer of peat fills the deepest part of the valley, and a stream may run through the surface of the bog. Valley bogs may develop in relatively dry and warm climates, but because they rely on ground or surface water, they only occur on acidic substrates. ==== Raised bog ==== These develop from a lake or flat marshy area, over either non-acidic or acidic substrates. Over centuries there is a progression from open lake, to a marsh, to a fen (or, on acidic substrates, valley bog), to a carr, as silt or peat accumulates within the lake. Eventually, peat builds up to a level where the land surface is too flat for ground or surface water to reach the center of the wetland. This part, therefore, becomes wholly rain-fed (ombrotrophic), and the resulting acidic conditions allow the development of bog (even if the substrate is non-acidic). The bog continues to form peat, and over time a shallow dome of bog peat develops into a raised bog. The dome is typically a few meters high in the center and is often surrounded by strips of fen or other wetland vegetation at the edges or along streamsides where groundwater can percolate into the wetland. The various types of raised bog may be divided into: Coastal bog Plateau bog Upland bog Kermi bog String bog Palsa bog Polygonal bog ==== Blanket bog ==== In cool climates with consistently high rainfall (on more than c. 235 days a year), the ground surface may remain waterlogged for much of the time, providing conditions for the development of bog vegetation. In these circumstances, bog develops as a layer "blanketing" much of the land, including hilltops and slopes. Although a blanket bog is more common on acidic substrates, under some conditions it may also develop on neutral or even alkaline ones, if abundant acidic rainwater predominates over the groundwater. A blanket bog can occur in drier or warmer climates, because under those conditions hilltops and sloping ground dry out too often for peat to form – in intermediate climates a blanket bog may be limited to areas which are shaded from direct sunshine. In periglacial climates a patterned form of blanket bog may occur, known as a string bog. In Europe, these mostly very thin peat layers without significant surface structures are distributed over the hills and valleys of Ireland, Scotland, England, and Norway. In North America, blanket bogs occur predominantly in Canada east of Hudson Bay. These bogs are often still under the influence of mineral soil water (groundwater). Blanket bogs do not occur north of the 65th latitude in the northern hemisphere. ==== Quaking bog ==== A quaking bog, schwingmoor, or swingmoor is a form of floating bog occurring in wetter parts of valley bogs and raised bogs and sometimes around the edges of acidic lakes. The bog vegetation, mostly sphagnum moss anchored by sedges (such as Carex lasiocarpa), forms a floating mat approximately half a meter thick on the surface of water or above very wet peat. White spruce (Picea pungens) may grow in this bog regime. Walking on the surface causes it to move – larger movements may cause visible ripples on the surface, or they may even make trees sway. The bog mat may eventually spread across the water surface to cover bays or even entire small lakes. Bogs at the edges of lakes may become detached and form floating islands. ==== Cataract bog ==== A cataract bog is a rare ecological community formed where a permanent stream flows over a granite outcropping. The sheeting of water keeps the edges of the rock wet without eroding the soil, but in this precarious location, no tree or large shrub can maintain a roothold. The result is a narrow, permanently wet habitat. == Uses == === Industrial uses === After drying, peat is used as a fuel, and it has been used that way for centuries. More than 20% of home heat in Ireland comes from peat, and it is also used for fuel in Finland, Scotland, Germany, and Russia. Russia is the leading exporter of peat for fuel, at more than 90 million metric tons per year. Ireland's Bord na Móna ("peat board") was one of the first companies to mechanically harvest peat, which is being phased out.The other major use of dried peat is as a soil amendment (sold as moss peat or sphagnum peat) to increase the soil's capacity to retain moisture and enrich the soil. It is also used as a mulch. Some distilleries, notably in the Islay whisky-producing region, use the smoke from peat fires to dry the barley used in making Scotch whisky.Once the peat has been extracted it can be difficult to restore the wetland, since peat accumulation is a slow process. More than 90% of the bogs in England have been damaged or destroyed. In 2011 plans for the elimination of peat in gardening products were announced by the UK government. === Other uses === The peat in bogs is an important place for the storage of carbon. If the peat decays, carbon dioxide would be released to the atmosphere, contributing to global warming. Undisturbed, bogs function as a carbon sink. As one example, the peatlands of the former Soviet Union were calculated to be removing 52 Tg of carbon per year from the atmosphere.: 41  Therefore, the rewetting of drained peatlands may be one of the most cost-effective ways to mitigate climate change.Peat bogs are also important in storing fresh water, particularly in the headwaters of large rivers. Even the enormous Yangtze River arises in the Ruoergai peatland near its headwaters in Tibet.: fig. 13.8 Blueberries, cranberries, cloudberries, huckleberries, and lingonberries are harvested from the wild in bogs. Bog oak, wood that has been partially preserved by bogs, has been used in the manufacture of furniture.Sphagnum bogs are also used for outdoor recreation, with activities including ecotourism and hunting. For example, many popular canoe routes in northern Canada include areas of peatland. Some other activities, such as all-terrain vehicle use, are especially damaging to bogs. == Archaeology == The anaerobic environment and presence of tannic acids within bogs can result in the remarkable preservation of organic material. Finds of such material have been made in Slovenia, Denmark, Germany, Ireland, Russia, and the United Kingdom. Some bogs have preserved bog-wood such as ancient oak logs useful in dendrochronology, and they have yielded extremely well-preserved bog bodies, with hair, organs, and skin intact, buried there thousands of years ago after apparent Germanic and Celtic human sacrifice. Excellent examples of such human specimens include the Haraldskær Woman and Tollund Man in Denmark, and Lindow man found at Lindow Common in England. The Tollund Man was so well preserved that when the body was discovered in 1950, the discoverers thought it was a recent murder victim and researchers were even able to tell the last meal that the Tollund Man ate before he died: porridge and fish. This process happens because of the low oxygen levels of bogs in combination with the high acidity. These anaerobic conditions lead to some of the best preserved mummies and offer a lot of archeological insight on society as far as 8,000 years back. Céide Fields in County Mayo in Ireland, a 5,000-year-old neolithic farming landscape has been found preserved under a blanket bog, complete with field walls and hut sites. One ancient artifact found in various bogs is bog butter, large masses of fat, usually in wooden containers. These are thought to have been food stores, of both butter and tallow. == Image gallery == == See also == == References == == Bibliography == Aiton, William (1811). General View of The Agriculture of the County of Ayr; observations on the means of its improvement; drawn up for the consideration of the Board of Agriculture, and Internal Improvements, with Beautiful Engravings. Glasgow. == External links == Ballynahone Bog Archived 19 October 2021 at the Wayback Machine Black Spruce Bog Describes a forested bog type of North America Bog bodies Germany's Endangered Bogs - slideshow by Der Spiegel 'Preserve peat bogs' for climate BBC 28 March 2007 "Bog" . Encyclopædia Britannica (11th ed.). 1911. "Bog" . The American Cyclopædia. 1879.

Landforms

Bolson

A bolson is a desert valley or depression, usually draining into a playa or salt pan, and entirely surrounded by recently uplifted hills or mountains. Bolsons are sites of active deposition of sediments (aggradation). They are a type of endorheic basin characteristic of basin and range topography. The term was an Americanism originating in the 1830s and 1840s during the explorations of the far west of North America, particularly of what became the Southwestern United States and northern Mexico. It was derived from the Spanish bolsón (large purse).Examples of this type of formation would be the Hueco Bolson in the western Trans-Pecos of Texas, and the Mesilla Bolson in southern New Mexico and the northeastern part of Chihuahua, Mexico. Bolsons are the locations of large aquifers of waters, accumulated over millennia in their deep layers of sediments, now many are being used to supply water to the populations in those areas. These are called bolson aquifers. == See also == Bolsón (disambiguation) == References ==

Landforms

Burn (landform)

In local usage, a burn is a kind of watercourse. The term applies to a large stream or a small river. The word is used in Scotland and England (especially North East England) and in parts of Ulster, Australia and New Zealand. == Etymology == The cognate of burn in standard English is "bourn", "bourne", "borne", "born", which is retained in placenames like Bournemouth, King's Somborne, Holborn, Melbourne. A cognate in German is Born (contemp. Brunnen), meaning "well", "spring" or "source", which is retained in placenames like Paderborn in Germany. Both the English and German words derive from the same Proto-Germanic root.Scots Gaelic has the word bùrn, also cognate, but which means "fresh water"; the actual Gaelic for a "burn" is allt (sometimes anglicised as "ault" or "auld" in placenames.) == Examples == == References == == External links == Scottish Words and Place-Names:Place-Name Glossary

Landforms

Carr (landform)

A carr is a type of waterlogged wooded terrain that, typically, represents a succession stage between the original reedy marsh and the likely eventual formation of forest in a sub-maritime climate. Carrs are wetlands that are dominated by shrubs rather than trees. The carr is one stage in a hydrosere: the progression of vegetation beginning from a terrain submerged by fresh water along a river or lake margin. In sub-maritime regions, it begins with reed-marsh. As the reeds decay, the soil surface eventually rises above the water, creating fens that allow vegetation such as sedge to grow. As this progression continues, riparian trees and bushes appear and a carr landscape is created – in effect a wooded fen in a waterlogged terrain. At this stage, overall, unlike the overwhelming acidity of decaying reeds, the pH is not too acidic and the soil is not too deficient in minerals, making a habitat for endemic and other wildlife. Characteristic water-tolerant trees include alder and willow. == Etymology == The word carr derives from the Old Norse kjarr, meaning "brushwood" in the word kjarr-mýrr, meaning "marsh overgrown with brushwood." Other descendants of kjarr include Icelandic kjarr "brushwood"; Norwegian kjarr, kjerr "brushwood"; Danish kær "swamp", Swedish kärr, same meaning. == References ==

Landforms

Carse

In Scottish geography, a Carse (the modern form of older Scots kerse; Scottish Gaelic càrrsa or còrrsa) is an area of fertile, low-lying (typically alluvial) land occupying certain Scottish river valleys, such as that of the River Forth. == Carse of Forth == The Carse of Forth contrasts with the Ochil Hills to the north, from which it is separated by the Ochil Fault. The carse is generally so flat that, except in the case of alluvial fans, such as that on which the small town of Alva is situated, it has only reached a height of about 9 metres above sea level at the Ochil Fault, typically two or more miles from the river. In the case of the River Forth, the carse extends some considerable distance above and below Stirling, where due to constraints such as the Abbey Craig to the north and the castle rock, on which the town is based, to the south, it is very narrow. The carse typically offers good agricultural land, however underlying the topsoil and alluvium is glacial boulder clay. In other places, especially in the west, the carse was overlain by peat bogs such as Flanders Moss, much of which has been cleared to improve agriculture. == Other carses == Carse of Gowrie, Perthshire, near Blairgowrie Carse of Lecropt near Bridge of Allan, Stirling Carse of Stirling Carse of Ae Carse of Falkirk Carse of Blair Drummond, Stirling Friar's Carse, Dumfries and Galloway Carsphairn The Carse (Inverness) Kinneil Kerse (West Lothian) Carse of Raddery (Ross and Cromarty) Carse Knowe (West Lothian) Kerse (Ayrshire) East Kerse Mains (West Lothian) Carsethorn (Kirkcudbright), Dumfries and Galloway Carse Grey estate near Forfar, plus nearby Carseburn and Carsebank (Angus) == References ==

Landforms

Cataract bog

A cataract bog is a rare ecological community formed where a permanent stream flows over a granite outcropping. The sheeting of water keeps the edges of the rock wet without eroding the soil; in this precarious location no tree or large shrub can maintain a roothold. The result is a narrow, permanently wet, sunny habitat. While a cataract bog is host to plants typical of a bog, it is technically a fen. Bogs get water from the atmosphere, while fens get their water from groundwater seepage.Cataract bogs inhabit a narrow, linear zone next to the stream and are partly shaded by trees and shrubs in the adjacent plant communities. Algae growing on the rocks can make the surface slippery and dangerous for those exploring a cataract bog. == Typical species == The rushing water carves out small depressions where soil accumulates, forming micro-islands that play host to plants that thrive with low levels of nutrients and shallow root structures. Typical species include Sphagnum moss; carnivorous plants such as round-leaf sundew (Drosera rotundifolia), pitcher plants (Sarracenia purpurea and S. jonesii), and horned bladderwort (Utricularia cornuta); several orchid species such as common grass pink (Calopogon tuberosus), small green wood-orchid (Platanthera clavellata), rose pogonia (Pogonia ophioglossoides), and nodding ladies'-tresses (Spiranthes cernua). Other plants found in cataract bogs are limeseep grass-of-Parnassus (Parnassia grandifolia), Indian paint brush (Castilleja coccinea), stiff cowbane (Oxypolis rigidior), Appalachian bluet (Houstonia serpyllifolia) and northern sundrops (Oenothera tetragona).The plant communities are fragile because of their tenuous attachment to thin soil above the rock substrate. During prolonged drought, the stream may dry up and the edges of the micro-islands curl up. Heavy rainfall can then wash away the micro-islands, so a cataract bog is in a continual state of change and renewal. == Location == Cataract bogs are found only in the southern Appalachian Mountains of the United States, at elevations of between 1,200 and 2,400 feet (370 and 730 m). They are restricted to the Blue Ridge Escarpment region of South Carolina and a small area of North Carolina, a region with exceptionally high rainfall. == References ==

Landforms

Chevron (land form)

A chevron is a wedge-shaped sediment deposit observed on coastlines and continental interiors around the world. The term chevron was originally used independently by Maxwell and Haynes and Hearty and others for large, V-shaped, sub-linear to parabolic landforms in southwestern Egypt and on islands in the eastern, windward Bahamas. == General == The Egyptian “chevrons” are active, wind-generated dunes, but the “chevrons” in the Bahamas are inactive and have been variously interpreted. The most common interpretation of large, chevron-shaped bed forms is that they are a form of parabolic dune, and that most examples are generated by wind action.Many chevrons can be found in Australia, but others are concentrated around the coastlines of the world. For instance there are chevrons in Hither Hills State Park on Long Island and in Madagascar (such as the Fenambosy Chevron), as well as in interior sites of the United States such as the Palouse region of eastern Washington State, the Great Sand Dunes National Park and Preserve, and White Sands National Park. == Formation == According to Hansen et al. 2015, powerful storms and changes in sea level rise can explain chevrons. An example of the formation of chevrons can be seen in the Bahamas, where the lightly indurated ooid sand ridges appear to have been created by the impact of strong waves over a long period of time. Subsequently, the internal structure of the chevrons showed that they were "rapidly emplaced by water rather than wind". The notion that chevrons are caused by powerful storm surges rather than wind can also be attributed to tsunami deposits, with examples of complex chevron formations being found several kilometres inland, at high elevations and on shorelines without beaches. The Holocene Impact Research Group hypothesizes that the formations could be caused by tsunamis from meteorite impacts or submarine slides which lift sediment up and carry it hundreds of miles until depositing it on coastlines. Part of the evidence they cite for this hypothesis is that the sediments contain tiny marine fossils; however, such fossils can be moved by the wind, just like sand. In 2017, Abbott et al. reported that the Madagascar chevrons contain considerable quantities of early Holocene carbonate samples that resemble marine foraminifera shells, including those that are partly dolomitized and others that are infilled with mud. These findings show that the chevrons' marine carbonate tests were eroded from the continental shelf, rather than from current beaches.The impact idea is controversial not only because chevrons are similar to wind-blown landforms found far from the ocean, but also because it is unlikely that there have been enough large impacts and landslides to explain the observed chevrons. Moreover, some computer models and sediment-transport analysis do not support this theory. For example, the orientation of chevrons along the southern coast of Madagascar do not line up with what these models of mega-tsunamis have simulated. Additional evidence against the mega-tsunami hypothesis is that the force of the water would not produce such regular bed forms. == See also == Chevron (geology) == Notes == == References == Blakeslee, Sandra (November 14, 2006), "Ancient Crash, Epic Wave", The New York Times Chevron image from New York Times

Landforms

Chute (gravity)

A chute is a vertical or inclined plane, channel, or passage through which objects are moved by means of gravity. == Landform == A chute, also known as a race, flume, cat, or river canyon, is a steep-sided passage through which water flows rapidly. Akin to these, man-made chutes, such as the timber slide and log flume, were used in the logging industry to facilitate the downstream transportation of timber along rivers. These are no longer in common use. Man-made chutes may also be a feature of spillways on some dams. Some types of water supply and irrigation systems are gravity fed, hence chutes. These include aqueducts, puquios, and acequias. == Building chute == Chutes are in common use in tall buildings to allow the rapid transport of items from the upper floors to a central location on one of the lower floors or basement. Chutes may be round, square or rectangular at the top and/or the bottom. Laundry chutes in hotels are placed on each floor to allow the expedient transfer and collection of dirty laundry to the hotel's laundry facility without having to use elevators or stairs. These chutes are generally aluminized steel and welded together to avoid any extruding parts that may rip or damage the materials.Home laundry chutes are placed on each floor of multistory homes allow the collection of all household members' dirty laundry to one location, conveniently next to the laundry facilities, without the constant transport of laundry bins from story-to-story or room-to-room or up and down stairs. Home laundry chutes may be less common than previously due to building codes or concern regarding fireblocking, the prevention of fire from spreading from floor-to-floor, as well as child safety. However, construction including cabinets, doors, lids, and locks may make both risks significantly less than with simple stairwells.Refuse chute or Garbage chutes are common in high-rise apartment buildings and are used to collect all the building's garbage in one place. Often the bottom end of the chute is placed directly above a large, open waste container. This makes garbage collection faster and more efficient. Mail chutes are used in some buildings to collect the occupants' mail. A notable example is the Asia Insurance Building. Escape chutes are used and proposed for use in evacuation of mining equipment and high-rise buildings. Construction chutes are used to remove rubble and similar demolition materials safely from taller buildings. These temporary structures typically consist of a chain of cylindrical or conical plastic tubes, each fitted into the top of the one below and tied together, usually with chains. Together they form a long flexible tube, which is hung down the side of the building. The lower end of this tube is placed over a skip or other receptacle, and waste materials are dropped into the top. Heavy duty steel chutes may also be used when the debris being deposited is heavy duty and in cases of particularly high buildings.An elevator is not a chute as it does not move by gravity. == Chutes in transportation == Goust, a hamlet in southwestern France, is notable for its mountainside chute that is used to transport coffins.Chutes are also found in: Hopper cars Hopper barges == References ==

Landforms

Col

In geomorphology, a col is the lowest point on a mountain ridge between two peaks. It may also be called a gap. Particularly rugged and forbidding cols in the terrain are usually referred to as notches. They are generally unsuitable as mountain passes, but are occasionally crossed by mule tracks or climbers' routes. The term col tends to be associated more with mountain rather than hill ranges. It is derived from the French col ("collar, neck") from Latin collum, "neck".The height of a summit above its highest col (called the key col) is effectively a measure of a mountain's topographic prominence. Cols lie on the line of the watershed between two mountains, often on a prominent ridge or arête. For example, the highest col in Austria, the Obere Glocknerscharte ("Upper Glockner Col", 3,766 m (AA)), lies between the Kleinglockner (3,783 m above sea level (AA)) and Grossglockner (3,798 m above sea level (AA)) mountains, giving the Kleinglockner a minimum prominence of 17 metres.The majority of cols are unnamed and are either never transited or only crossed in the course of negotiating a ridge line. Many double summits are separated by prominent cols. The distinction with other names for breaks in mountain ridges such as saddle, wind gap or notch is not sharply defined and may vary from place to place. == See also == Arête – Narrow ridge of rock which separates two valleys Saddle (landform) == References == == External links == Illustrated Glossary of Alpine Mountain Landforms: Col. Retrieved 16 August 2015.

Landforms

Couloir

A couloir (French: [ku.lwaʁ], "passage" or "corridor") is a narrow gully with a steep gradient in a mountainous terrain. == Geology == A couloir may be a seam, scar, or fissure, or vertical crevasse in an otherwise solid mountain mass. Though often hemmed in by sheer cliff walls, couloirs may also be less well-defined, and often simply a line of broken talus or scree ascending the mountainside and bordered by trees or other natural features. Couloirs are especially significant in winter months when they may be filled in with snow or ice, and become much more noticeable than in warmer months when most of the snow and ice may recede. These physical features make the use of couloirs popular for both mountaineering and extreme skiing. == References ==

Landforms

Cyclopean stairs

Cyclopean stairs form as a result of glacial erosion. The term refers to the longitudinal profile of a glaciated valley that has several consecutive hanging valleys. == Formation == There are a few different ways cyclopean stairs can form. One way they form is through plucking. Different bedrock types may be more susceptible to plucking. If a highly jointed layer of bedrock is on the surface, large portions of it will be picked up by the glacier and deposited later as a glacial erratic. The valley formed in this fashion may have a steep wall at its head caused by a change in the bedrock type. The stronger bedrock will remain in the form of a riser at the end of a hanging valley. Cyclopean stairs can also form at points where tributary glaciers feed into larger central glaciers. The tributary glacier causes the central glacier to thicken and downcut more rapidly. This may cause a very sudden drop in the valley floor at the points where the glaciers converged. They may also form at the head of a glacier. In an area where the snowline is rising, the cirque in which the glacier forms my recede. A new cirque may form above the previous cirque and carve out a new step. As the snowline continues to rise, new cirques would continue to form the steps of the cyclopean stairs. == References == Surface Processes and Landforms, Don J. Easterbrook. Prentice Hall, New Jersey, 1999.

Landforms

Dale (landform)

A dale is an open valley. Dale is a synonym of the word valley. The name is used when describing the physical geography of an area. It is used most frequently in the Lowlands of Scotland and in the North of England; the term "fell" commonly refers to the mountains or hills that flank the dale. == Etymology == The word dale comes from the Old English word dæl, from which the word "dell" is also derived. It is also related to Old Norse word dalr (and the modern Icelandic word dalur), which may perhaps have influenced its survival in northern England. The Germanic origin is assumed to be *dala-. Dal- in various combinations is common in placenames in Norway. Modern English valley and French vallée are presumably not related to dale. A distant relative of dale is currency unit dollar, stemming from German thaler or daler, short for joachimsthaler coins manufactured in the town of Joachimsthal in Bohemia.The word is perhaps related to Welsh dol (meadow, pasture, valley), Russian dol (valley, reverse side) and Serbian/Croatian/Bulgarian/Russian dolina (basin, doline is a geological term for certain surface depressions in karst areas). There is semantic equivalency to many words and phrases, suggesting a common Indo-European affinity. Vale and thalweg are also related. == Examples == The following are several examples of major dales that have the name dale. The river name is usually appended with "-dale". There are also many smaller dales; this is not an exhaustive list (see dale (place name element) for more). Airedale (Yorkshire) Annandale (Dumfries & Galloway) Calderdale (Yorkshire) Clydesdale (Lanarkshire) Coquetdale (Northumberland) Eskdale (Cumbria) Eskdale (Dumfries & Galloway) Eskdale (Yorkshire) Lauderdale (Scottish Borders) Lonsdale (or Lunesdale, valley of the Lune, Lancashire-Cumbria) Nithsdale (Dumfries & Galloway) Rochdale (Greater Manchester) Teesdale (Durham) Tweeddale (Scottish Borders) Tynedale (Northumberland) Weardale (Durham) Wensleydale (or Yoredale, valley of the Ure, Yorkshire)The name Wuppertal (North Rhine-Westphalia) is similar in form. == References ==

Landforms

Dambo

A dambo is a class of complex shallow wetlands in central, southern and eastern Africa, particularly in Zambia, Malawi and Zimbabwe. They are generally found in higher rainfall flat plateau areas and have river-like branching forms which in themselves are not very large but combined add up to a large area. Dambos have been estimated to comprise 12.5% of the area of Zambia. Similar African words include mbuga (commonly used in East Africa), matoro (Mashonaland), vlei (South Africa), fadama (Nigeria), and bolis (Sierra Leone); the French bas-fond and German Spültal have also been suggested as referring to similar grassy wetlands. == Characteristics == Dambos are characterised by grasses, rushes and sedges, contrasting with surrounding woodland such as miombo woodland. They may be substantially dry at the end of the dry season, revealing grey soils or black clays, but unlike a flooded grassland, they retain wet lines of drainage through the dry season. They are inundated (waterlogged) in the wet season but not generally above the height of the vegetation, and any open water surface is usually confined to streams and small ponds or lagoons (called pans) at the lowest point generally near the centre. The name dambo is most frequently used for wetlands on flat plateaus which form the headwaters of streams. The definition for scientific purposes has been proposed as “seasonally waterlogged, predominantly grass covered, depressions bordering headwater drainage lines”. == Types == The problem with the preceding definition is that the word may also be used for wetlands bordering rivers far from the headwaters, for example the dambo of the Mbereshi River where it enters the swamps of the Luapula River in Zambia, 09°43′30″S 28°46′00″E. A 1998 report of the Food and Agriculture Organization distinguishes between ‘hydromorphic/phreatic’ dambos (associated with headwaters) and ‘fluvial’ dambos (associated with rivers), and also referred to five geomorphological types in Zambia’s Luapula Province: upland, valley, hanging, sand dune and pan dambos. == Hydrology == Dambos are fed by rainfall which drains out slowly to feed streams and are therefore a vital part of the water cycle. As well as being complex ecosystems, they also play a role in the biodiversity of the region.There is a popular idea that dambos act like sponges to soak up the wet season rain which they release slowly into rivers during the dry season thus ensuring a year-round flow, but this is opposed by some research which suggests that in the middle to late dry season the water is actually released from aquifers. Springs are seen in some dambos. Thus it may take a long time—perhaps several years—for water from a heavy rainy season to percolate through hills and emerge in a dambo, creating lagoons there or a flow in downstream rivers which cannot be explained by the previous year's rainfall. Dambos may be involved, for instance, in explaining puzzling variations in water level or flow in Lake Mweru Wantipa and Lake Chila in Mbala. == Use == Traditionally, dambos have been exploited: as a dry-season water source for rushes used as thatching and fencing material for clay used for building, brick-making and earthenware for hunting (especially birds and small antelope) for growing vegetables and other food crops, which can be vital in drought years since dambo soils usually retain enough moisture to produce a harvest when the rains fail for soaking bitter cassava in dug ponds for fishing (generally using fish traps) in those dambos with streamsMore recently, they have been used for fish ponds and growing upland rice. Efforts to develop dambos agriculturally have been hampered by a lack of research on the hydrology and soils of dambos, which have proved to be variable and complex. == Example == A dambo can be seen at 11°28′S 28°54′E (30 km south of Mansa, Zambia) in a forest reserve. Unlike in the neighbouring areas which have been cleared for farming and charcoal-burning, the dambo contrasts well with the undisturbed miombo woodland canopy. Headwater dambos have a branching structure like rivers. Most of the dambos have roughly the same width and form the same sort of pattern. An example of a pan dambo can be seen at 16°22.003′S 24°18.580′E (102 km north-west of Mulobezi, Zambia). The water in the pan has dried out, and the grass has been burnt off giving the dark appearance at the centre of the dambo. To the east and west of the pan dambo a series of dambos can be seen along two river courses. == References ==

Landforms

De Geer Land Bridge

The De Geer Land Bridge was a land bridge that connected Fennoscandia to northern Greenland. The land bridge provided a northern route from Europe to North America from the Late Cretaceous to the Early Paleocene, although this timeframe has been disputed.The De Geer Land Bridge provided a path from Scandinavia across the Barents Sea to Svalbard, northern Greenland, and northern Canada. This may have been possible due to the Barents Sea residing on the shallow continental shelf. == Relation to other land bridges == The De Geer Land Bridge was the initial route from Europe and North America. Long after the De Geer Land Bridge disappeared, the Thule Land Bridge appeared and offered a more southern route from Europe to North America.Beringia, a land bridge from Northeast Asia to Alaska, was another route to North America that existed at the same time as the De Geer Land Bridge. == References ==

Landforms

Fairy circle (arid grass formation)

Fairy circles are circular patches of land barren of plants, varying between 2 and 12 metres (7 and 39 ft) in diameter, often encircled by a ring of stimulated growth of grass. They occur in the arid grasslands of the Namib desert in western parts of Southern Africa, and in a part of the Pilbara in Western Australia. Studies have posited various hypotheses about their origins, but none have conclusively proven how they are formed. Theories include the activities of various types of termites, or the consequence of vegetation patterns that arise naturally from competition between grasses. In the languages of the Aboriginal Australian peoples who inhabit the Pilbara, they are known as linyji (Manyjilyjarra language) or mingkirri (Warlpiri language). == Location == Until 2014, the phenomenon was only known to occur in the arid grasslands of the Namib desert in western parts of Southern Africa, being particularly common in Namibia. In that year, ecologists were alerted to similar rings of vegetation outside Africa, in a part of the Pilbara in Western Australia.In Africa, the circles occur in a band lying about 160 kilometres (100 mi) inland, and extending southward from Angola for some 2,400 kilometres (1,500 mi) down to the Northwestern Cape province of South Africa. It is largely a remote and inhospitable region, much of it over a hundred kilometres from the nearest village. The circles have been recognised and informally remarked on for many years, first being mentioned in technical literature in the 1920s and intermittently thereafter with the intensity of study increasing during the final quarter of the 20th century.In 2014, fairy circles were first discovered outside Africa, 15 km (9.3 mi) outside of the town Newman, in the Pilbara region of Western Australia. Australian environmental engineer Bronwyn Bell, alongside Stephan Getzin from the Helmholtz Centre for Environmental Research, released a paper in 2016, providing new insight into possible cause of the fairy circle formations.Examples can be found at 24.95°S 15.93°E / -24.95; 15.93 (Namibia) and 23.45°S 119.85°E / -23.45; 119.85 (Western Australia) == Description == Fairy circles typically occur in essentially monospecific grassy vegetation, where conditions are particularly arid. Associated grasses commonly are species in the genus Stipagrostis. Studies show that these circles pass through a life cycle of some 30 to 60 years. They become noticeable at a diameter of about 2 metres (6 ft 7 in), achieving a peak diameter of perhaps 12 metres (39 ft), after which they mature and "die" as they undergo invasion, mainly by grasses.In the languages of the Martu and Warlpiri peoples of Western Australia, fairy circles are known as "linyji" in the Manyjilyjarra language and "mingkirri" in the Warlpiri language. == Theories of formation == Like heuweltjies in South Africa and Mima mounds in the U.S., the cause of fairy circles has long been a puzzle and the investigation has proved challenging. Fairy circles in Namibia may be created in a different way from those in Australia, because they formed on sand rather than clay.In 2004, University of Pretoria botanist Gretel van Rooyen rejected proposals of termite activity, radioactive soil, and of plant toxins. In 2008, Angelique Joubert proposed that residual plant toxins remaining in the soil after the death of Euphorbia damarana plants might be the cause of the barren interiors of the circles.In 2012, Eugene Moll suggested the termite species Baucaliotermes hainsei and Psammotermes allocerus as the creator of these circles. All rings have been found to contain termite casts, and radar investigations suggest that a moist layer of soil is situated beneath the fairy circles.In 2013, this theory was supported by Norbert Juergens. Juergens found evidence that the sand termite, Psammotermes allocerus, generates a local ecosystem that profits from and promotes the creation of the fairy circle. The sand termite was found in 80-100% of the circles, in 100% of newly formed circles, and was the only insect to live across the range of the phenomenon. Sand termites create the fairy circle by consuming vegetation and burrowing in the soil to create the ring. The barren circle allows water to percolate down through sandy soil and accumulate underground, allowing the soil to remain moist even under the driest conditions. Grass growth around the circle is promoted by the accumulated soil water, and in turn the termites feed on the grasses, slowly increasing the diameter of the circle. This behaviour on the part of Psammotermes allocerus amounts to creation of a local ecosystem in a manner analogous to behaviour of the common beaver.Walter R. Tschinkel, a biologist at Florida State University, who also researched the fairy circles, remarked that Juergens, "has made the common scientific error of confusing correlation (even very strong correlation) with causation". Previously, Tschinkel had searched for harvester termites without success. Juergens responded that sand termites differ from harvester termites and live deep beneath the circle; they do not create mounds or nests above ground, and they leave no tracks in the sand. In such respects the sand termite is unusually inconspicuous in its activities. Unresolved questions remain about the soil from the centre of the circle inhibiting plant growth and the interactions of other species in the fairy circle as they relate to the local ecosystem. The received wisdom from about a century ago remarked on the "heuweltjies" being anomalously rich in plant nutrients, raising the question of how many effectively different types or circumstances of circles or heuweltjies there might be.Later in 2013, Michael Cramer and Nichole Barger suggested that the circles were the consequence of vegetation patterns that arose naturally from competition between grasses. They examined the conditions under which fairy circles arise and found that fairy circles are negatively correlated with precipitation and soil nutrition. This observation is consistent with resource competition being a cause of the crop circles. Grassy landscapes with a mixture of grasses can result in barren spots as a consequence of under-ground competition between different types of grasses. The patches are maintained because they form a reservoir of nutrients for the taller grasses at the periphery and possibly because of the activity of termites, as in the theory above. Using rainfall, biomass and temperature seasonality, they can predict with high accuracy the presence or absence of fairy circles in a region. According to Walter Tschinkel, this theory accounts for all the characteristics of fairy circles, including the presence of tall grass species. Other recent work has considered interacting combinations of both animal- and vegetation-induced patterning effects as a potential unifying theoretical explanation for the fairy circle phenomenon.A 2015 theory about the Australian fairy circles suggested that the distinct vegetation patterns are a population-level consequence of competition for scarce water, as the plants "organise" themselves to maximise access to scarce resources. The circular barren patches capture water which then flows to the outer edges of the ring. More water available increases biomass and roots which leads to the soil becoming looser. The less dense soil allows more water to penetrate and feed the vegetation, creating a feedback loop supporting the plants at the edge of the circle. Field observations by Sujith Ravi, Lixin Wang and colleagues using soil moisture, soil particle size, and soil water infiltration measurements in Namibia in 2015 and 2016 support this.In 2021 an explanation using hydrological feedbacks and the Turing mechanism was proposed as the cause of the patterns in Australia.In February 2023, weak seeps of hydrogen through faults, fractures, and diffused through rocks, were identified as a possible cause of the depressions. One researcher suggested that "hydrogen-loving microbes" may consume all other nutrients in the soil.An Australian cross-cultural study published in April 2023, involving local Martu peoples and using their traditional knowledge of the phenomenon, are pavement nests occupied by Drepanotermes (Australian harvester termites). The research showed that the circles may have been created in the Pleistocene (over 12,000 years ago), and that termites lived in them and were continuing to build them. Aboriginal peoples have lived on the Australian continent for up to 65,000 years and have deep knowledge passed down through their oral traditions. === Myths === In the oral myths of the Himba people of the Kunene Region of northern Namibia, these barren patches are said to have been caused by the gods, spirits and/or natural divinities. The region's bushmen have traditionally ascribed spiritual and magical powers to them. Of specific beliefs, the Himba people note that their original ancestor, Mukuru, was responsible for the creation of the fairy circles, or that they were the footprints of gods.Another myth put forth, promoted by some tour guides in Namibia, is that the circles are formed by a dragon in the earth and that its poisonous breath kills the vegetation. == Use == The Himba people use the fairy circles in their agriculture. Because fairy circles support grasses in otherwise barren land, they provide grazing. Sometimes they erect temporary wooden fences around the circles to corral young cattle for overnight protection against predators. == See also == Media related to Fairy circles at Wikimedia Commons Fairy ring Forest ring Hodotermitidae Creosote bush rings List of unsolved problems in biology Patterns in nature Tiger bush == References == == Further reading == Alvarez, Amanda (27 June 2012). "Scientist uses satellites to examine circles in African desert". Journal Sentinel.

Landforms

Fell

A fell (from Old Norse fell, fjall, "mountain") is a high and barren landscape feature, such as a mountain or moor-covered hill. The term is most often employed in Fennoscandia, Iceland, the Isle of Man, parts of northern England, and Scotland. == Etymology == The English word "fell" comes from Old Norse fell and fjall (both forms existed). It is cognate with Danish fjeld, Faroese fjall and fjøll, Icelandic fjall and fell, Norwegian fjell with dialects fjøll, fjødd, fjedd, fjedl, fjill, fil(l), and fel, and Swedish fjäll, all referring to mountains rising above the alpine tree line. == British Isles == In northern England, especially in the Lake District and in the Pennine Dales, the word "fell" originally referred to an area of uncultivated high ground used as common grazing usually on common land and above the timberline. Today, generally, "fell" refers to the mountains and hills of the Lake District and the Pennine Dales. Names that originally referred to grazing areas have been applied to these hilltops. This is the case with Seathwaite Fell, for example, which would be the common grazing land used by the farmers of Seathwaite. The fellgate marks the road from a settlement onto the fell (see photograph for example), as is the case with the Seathwaite Fell. In other cases the reverse is true; for instance, the name of Wetherlam, in the Coniston Fells, though understood to refer to the mountain as a whole, strictly speaking refers to the summit; the slopes have names such as Tilberthwaite High Fell, Low Fell and Above Beck Fells. The word "fell" is also used in the names of various breeds of livestock, bred for life on the uplands, such as Rough Fell sheep, Fell terriers and Fell ponies. It is also found in many place names across the north of England, often attached to the name of a community; thus the township of Cartmel Fell. In northern England, there is a Lord of the Fells – this ancient aristocratic title being associated with the Lords of Bowland. Groups of cairns are a common feature on many fells, often marking the summit – there are fine examples on Wild Boar Fell in Mallerstang Dale, Cumbria, and on Nine Standards Rigg just outside Kirkby Stephen, Cumbria. As the most mountainous region of England, the Lake District is the area most closely associated with the sport of fell running, which takes its name from the fells of the district. "Fellwalking" is also the term used locally for the activity known in the rest of Great Britain as hillwalking. The word "fell" also enjoys limited use in Scotland; with, for example, the Campsie Fells in central Scotland, to the north-east of Glasgow. One of the most famous examples of the use of the word "fell" in Scotland is Goat Fell, the highest point on the Isle of Arran. Criffel and the nearby Long Fell in Galloway may be seen from the northern Lake District of England. Peel Fell in the Kielder Forest is on the border between the Scottish Borders to the north and the English county of Northumberland to the south. == Fennoscandia == === Norway === In Norway, fjell, in common usage, is generally interpreted as simply a summit or area of greater altitude than a hill, which leads to a great deal of local variation in what is defined as a fjell. Fjell is mostly used about areas above the forest line. Distinct summits can be referred to as et fjell (a mountain). High plateaus (vidde landscape) such as Hardangervidda are also regarded as fjell. Professor of geography at the University of Bergen, Anders Lundeberg, has summed up the problem by stating, "There simply is no fixed and unambiguous definition of fjell." Ivar Aasen defined fjell as a "tall berg", primarily referring to a berg that reaches an altitude where trees don't grow, lower berg are referred to as "berg", ås (hill, ridge) or hei (moor, heathland). The fixed expression til fjells refers to mountains (or uplands) as a collective rather than a specific location or specific summit (the "s" in til fjells is an old genitive form remaining only in fixed expressions). According to Ivar Aasen, berg refers to cliffs, bedrock and notable elevations of the surface underpinned by bedrock; berg also refers to the substance of bedrock. For all practical purposes, fjell can be translated as "mountain" and the Norwegian language has no other commonly used word for mountain. === Sweden === In Sweden, fjäll generally refers to any mountain or upland high enough that forest will not naturally survive at the top, in effect a mountain tundra. Fjäll is primarily used to describe mountains in the Nordic countries, but also more generally to describe mountains shaped by massive ice sheets, primarily in Arctic and subarctic regions. There are however dialectal differences in usage, with comparatively low mountains or plateaus, sometimes tree-covered, in Bohuslän and Västergötland (e.g. Safjällets nationalpark and Kynnefjäll) being referred to as "fjäll", similar to how the word is used in Norwegian === Finland === In Finnish, the mountains characteristic of the region of Lapland are called tunturi (plural: tunturit), i.e. "fell". A tunturi is a hill high enough that its top is above the tree line and has alpine tundra. In Finnish, the geographical term vuori is used for mountains recently uplifted and with jagged terrain featuring permanent glaciers, while tunturi refers to the old, highly eroded, gently shaped terrain without glaciers, as found in Finland. They are round inselbergs rising from the otherwise flat surroundings. The tree line can be at a rather low altitude, such as 600 m in Enontekiö, owing to the high latitude. The fells in Finnish Lapland form vestiges of the Karelides mountains, formed two billion years ago. The term tunturi is also generally used to refer to treeless plains at high altitudes in far north regions. The term tunturi, originally a word limited to far-Northern dialects of Finnish and Karelian, is a loan from Sami, compare Proto-Sami *tuontër, South Sami doedtere, Northern Sami duottar, Inari Sami tuodâr "uplands, mountains, tundra", Kildin Sami tūndâr, which means "uplands, treeless mountain tract" and is cognate with Finnish tanner "hard ground". From this Sami word, the word "tundra" is borrowed, as well, through the Russian language. Hills that are over 50 m high, but do not reach the tree line are referred to as vaara, while the general term for hills including hills of 50 m or less is mäki. In place names, however, tunturi, vaara and vuori are used inconsistently, e.g. Rukatunturi is technically a vaara, as it lacks alpine tundra. === Förfjäll === The term förfjäll (literally "fore-fell") is used in Sweden and Finland to denote mountainous zones lower and less dissected than the fell proper. However, its more pronounced relief, its often higher amount of plateaux, and its coherent valley systems distinguishes the förfjäll also from the undulating hilly terrain (bergkullsterräng) and the plains with residual hills (bergkullslätt). Generally, the förfjäll do not surpass 1000 m ASL. As a geomorphic unit, the förfjäll extends across Sweden as a 650 km-long and 40 km to 80 km-broad belt from Dalarna in the south to Norrbotten in the north. == Scandinavian and English terms == bekkr - 'stream' » beck dalr - 'valley' » dale fors - 'waterfall' » force/foss fjallr - 'mountain' (usually a large, flat mountain) » fell gil - 'ravine' » gill/ghyll haugr - 'hill' » howe pic - 'peak' » pike sætr - 'shieling' » side/seat tjorn - 'small lake' » tarn þveit - 'clearing' » thwaite ness - 'headland' » ness == See also == Fell farming Fell Terrier List of fells in the Lake District List of Wainwrights (the 214 fells described in A. Wainwright's Pictorial Guide to the Lakeland Fells) The Outlying Fells of Lakeland List of Birketts (the 541 fells in Bill Birketts Complete Lakeland Fells) Middlesex Fells, a rocky highland just north of Boston, Massachusetts Snaefell, Isle of Man Nunatak == Notes == == References ==

Landforms

Fellfield

A fellfield or fell field comprises the environment of a slope, usually alpine or tundra, where the dynamics of frost (freeze and thaw cycles) and of wind give rise to characteristic plant forms in scree interstices. == Soil dynamics == The freeze-thaw cycles tend to push plants out of the soil. In addition, the high porosity of the soil makes a fellfield a difficult place for plants to grow. Fellfields often have typical patterns of rocks: lines of rocks that have been pushed out of the soil, and slid into a low region. == Botany == In botany the term "fellfield" describes an ecoregion, ecosystem, habitat, or plant community. The term frequently used is alpine fellfield. Fellfield is usually applied to an alpine tundra region of high altitude mountains, or high latitude islands, and the alpine plants there. === Flora === Fellfields are typically populated by cushion plants: perennials that grow close to the ground. Cushion plants are well-adapted to the dryness and short growing season of a fellfield. Cushion plants often have hairy foliage and long taproots, to gather and retain moisture. Examples of cushion plants include the lupines and buckwheats. ==== Fellfield species ==== Alpine flora list Azorella selago Oenothera xylocarpa Calyptridium umbellatumSome geologists find it is controversial to share the term for biology and geomorphology applications. == See also == Feldmark == References ==

Landforms

Fen

A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. The unique water chemistry of fens is a result of the ground or surface water input. Typically, this input results in higher mineral concentrations and a more basic pH than found in bogs. As peat accumulates in a fen, groundwater input can be reduced or cut off, making the fen ombrotrophic rather than minerotrophic. In this way, fens can become more acidic and transition to bogs over time.Fens can be found around the world, but the vast majority are located at the mid to high latitudes of the Northern Hemisphere. They are dominated by sedges and mosses, particularly graminoids that may be rarely found elsewhere, such as the sedge species Carex exilis. Fens are highly biodiverse ecosystems and often serve as habitats for endangered or rare species, with species composition changing with water chemistry. They also play important roles in the cycling of nutrients such as carbon, nitrogen, and phosphorus due to the lack of oxygen (anaerobic conditions) in waterlogged organic fen soils.Fens have historically been converted to agricultural land. However, fens face a number of other threats, including peat cutting, pollution, invasive species, and nearby disturbances that lower the water table in the fen, such as quarrying. Interrupting the flow of mineral-rich water into a fen changes the water chemistry, which can alter species richness and dry out the peat. Drier peat is more easily decomposed and can even burn. == Distribution and extent == Fens are distributed around the world, but are most frequently found at the mid-high latitudes of the Northern Hemisphere. They are found throughout the temperate zone and boreal regions, but are also present in tundra and in specific environmental conditions in other regions around the world. In the United States, fens are most common in the Midwest and Northeast, but can be found across the country. In Canada, fens are most frequent in the lowlands near Hudson Bay and James Bay, but can also be found across the country. Fens are also spread across the northern latitudes of Eurasia, including Britain and Ireland, as well as Japan, but east-central Europe is especially rich in fens. Further south, fens are much rarer, but do exist under specific conditions. In Africa, fens have been found in the Okavango Delta in Botswana and the highland slopes in Lesotho. Fens can also be found at the colder latitudes of the Southern Hemisphere. They are found in New Zealand and southwest Argentina, but the extent is much less than that of the northern latitudes. Locally, fens are most often found at the intersection of terrestrial and aquatic ecosystems, such as the headwaters of streams and rivers.It is estimated that there are approximately 1.1 million square kilometers of fens worldwide, but quantifying the extent of fens is difficult. Because wetland definitions vary regionally, not all countries define fens the same way. In addition, wetland data is not always available or of high quality. Fens are also difficult to rigidly delineate and measure, as they are located between terrestrial and aquatic ecosystems. == Definition == Rigidly defining types of wetlands, including fens, is difficult for a number of reasons. First, wetlands are diverse and varied ecosystems that are not easily categorized according to inflexible definitions. They are often described as a transition between terrestrial and aquatic ecosystems with characteristics of both. This makes it difficult to delineate the exact extent of a wetland. Second, terms used to describe wetland types vary greatly by region. The term bayou, for example, describes a type of wetland, but its use is generally limited to the southern United States. Third, different languages use different terms to describe types of wetlands. For instance, in Russian, there is no equivalent word for the term swamp as it is typically used in North America. The result is a large number of wetland classification systems that each define wetlands and wetland types in their own way. However, many classification systems include four broad categories that most wetlands fall into: marsh, swamp, bog, and fen. While classification systems differ on the exact criteria that define a fen, there are common characteristics that describe fens generally and imprecisely. A general definition provided by the textbook Wetlands describes a fen as "a peat-accumulating wetland that receives some drainage from surrounding mineral soil and usually supports marsh like vegetation."Three examples are presented below to illustrate more specific definitions for the term fen. === Canadian Wetland Classification System definition === In the Canadian Wetland Classification System, fens are defined by six characteristics: Peat is present. The surface of the wetland is level with the water table. Water flows on the surface and through the subsurface of the wetland. The water table fluctuates. It may be at the surface of the wetland or a few centimeters above or below it. The wetland receives a significant amount of its water from mineral-rich groundwater or surface water. Decomposed sedges or brown moss peat are present. The vegetation is predominantly graminoids and shrubs. === Wetland Ecology: Principles and Conservation (Keddy) definition === In the textbook Wetland Ecology: Principles and Conservation, Paul A. Keddy offers a somewhat simpler definition of a fen as "a wetland that is usually dominated by sedges and grasses rooted in shallow peat, often with considerable groundwater movement, and with pH greater than 6." This definition differentiates fens from swamps and marshes by the presence of peat. === The Biology of Peatlands (Rydin) definition === In The Biology of Peatlands fens are defined by the following criteria: The wetland is not flooded by lake or stream water. Woody vegetation 2 meters or taller is absent or canopy cover is less than 25%. The wetland is minerotrophic (it receives its nutrients from mineral-rich groundwater).A further distinction is made between open and wooded fens, where open fens have canopy cover less than 10% and wooded fens have 10–25% canopy cover. If tall shrubs or trees dominate, the wetland is instead classified as a wooded bog or swamp forest, depending on other criteria. == Biogeochemical features == === Hydrological conditions === Hydrologyal conditions, as seen in other wetlands, are a major determinant of fen biota and biogeochemistry. Fen soils are constantly inundated because the water table is at or near the surface. The result is anaerobic (oxygen-free) soils due to the slow rate at which oxygen diffuses into waterlogged soil. Anaerobic soils are ecologically unique because earth's atmosphere is oxygenated, while most terrestrial ecosystems and surface waters are aerobic. The anaerobic conditions found in wetland soils result in reduced, rather than oxidized, soil chemistry.A hallmark of fens is that a significant portion of their water supply is derived from groundwater (minerotrophy). Because hydrology is the dominant factor in wetlands, the chemistry of the groundwater has an enormous effect on the characteristics of the fen it supplies. Groundwater chemistry, in turn, is largely determined by the geology of the rocks that the groundwater flows through. Thus, the characteristics of a fen, especially its pH, are directly influenced by the type of rocks its groundwater supply contacts. pH is a major factor in determining fen species composition and richness, with more basic fens called "rich" and more acidic fens called "poor." Rich fens tend to be highly biodiverse and harbor a number of rare or endangered species, and biodiversity tends to decrease as the richness of fen decreases.Fens tend to be found above rocks that are rich in calcium, such as limestone. When groundwater flows past calcareous (calcium-rich) rocks like limestone (calcium carbonate), a small amount dissolves and is carried to the fen supplied by the groundwater. When calcium carbonate dissolves, it produces bicarbonate and a calcium cation according to the following equilibrium: CaCO 3 + H 2 CO 3 ↽ − − ⇀ Ca 2 + + 2 HCO 3 − {\displaystyle {\ce {CaCO3 + H2CO3 <=> Ca^2+ + 2HCO3^-}}} where carbonic acid (H2CO3) is produced by the dissolution of carbon dioxide in water. In fens, the bicarbonate anion produced in this equilibrium acts as a pH buffer, which keeps the pH of the fen relatively stable. Fens supplied by groundwater that doesn't flow through minerals and act as a buffer when dissolved tend to be more acidic. The same effect is observed when groundwater flows through minerals with low solubility, such as sand.In extreme rich fens, calcium carbonate can precipitate out of solution to form marl deposits. Calcium carbonate precipitates out of solution when the partial pressure of carbon dioxide in the solution falls. The decrease in carbon dioxide partial pressure is caused by uptake by plants for photosynthesis or direct loss to the atmosphere. This reduces the availability of carbonic acid in solution, shifting the above equilibrium back towards the formation of calcium carbonate. The result is the precipitation of calcium carbonate and the formation of marl. === Nutrient cycling === Fen, being a distinct type of wetland, shares many biogeochemical characteristics with other wetlands. Like all wetlands, they play an important role in nutrient cycling because they are located at the interface of aerobic (oxic) and anaerobic (anoxic) environments. Most wetlands have a thin top layer of oxygenated soil in contact with the atmosphere or oxygenated surface waters. Nutrients and minerals may cycle between this oxidized top layer and the reduced layer below, undergoing oxidation and reduction reactions by the microbial communities adapted to each layer. Many important reactions take place in the reduced layer, including denitrification, manganese reduction, iron reduction, sulfate reduction, and methanogenesis. Because wetlands are hotspots for nutrient transformations and often serve as nutrient sinks, they may be constructed to treat nutrient-rich waters created by human activities.Fens are also hotspots for primary production, as the continuous input of groundwater stimulates production. Bogs, which lack this input of groundwater, have much lower primary production. ==== Carbon ==== Carbon from all types of wetlands, including fens, arrives mostly as organic carbon from either adjacent upland ecosystems or by photosynthesis in the wetland itself. Once in the wetland, organic carbon generally has three main fates: oxidation to CO2 by aerobic respiration, burial as organic matter in peat, or decomposition to methane. In peatlands, including fens, primary production by plants is greater than decomposition, which results in the accumulation of organic matter as peat. Resident mosses usually carry out decomposition within the fen, and temperate fens are often driven by plant roots' decomposition. These peat stores sequester an enormous amount of carbon. Nevertheless, it is difficult to determine whether fens net take up or emit greenhouse gases. This is because fens emit methane, which is a more potent greenhouse gas than carbon dioxide. Methanogenic archaea that reside in the anaerobic layers of peat combine carbon dioxide and hydrogen gas to form methane and water. This methane can then escape into the atmosphere and exert its warming effects. Peatlands dominated by brown mosses and sedges such as fens have been found to emit a greater amount of methane than Sphagnum-dominated peatlands such as bogs. ==== Nitrogen ==== Fens play an important role in the global nitrogen cycle due to the anaerobic conditions found in their soils, which facilitate the oxidation or reduction of one form of nitrogen to another. Most nitrogen arrives in wetlands as nitrate from runoff, in organic matter from other areas, or by nitrogen fixation in the wetland. There are three main forms of nitrogen found in wetlands: nitrogen in organic matter, oxidized nitrogen (nitrate or nitrite), and ammonium.Nitrogen is abundant in peat. When the organic matter in peat is decomposed in the absence of oxygen, ammonium is produced via ammonification. In the oxidized surface layer of the wetland, this ammonium is oxidized to nitrite and nitrate by nitrification. The production of ammonium in the reduced layer and its consumption in the top oxidized layer drives upward diffusion of ammonium. Likewise, nitrate production in the oxidized layer and nitrate consumption in the reduced layer by denitrification drives downward diffusion of nitrate. Denitrification in the reduced layer produces nitrogen gas and some nitrous oxide, which then exit the wetland to the atmosphere. Nitrous oxide is a potent greenhouse gas whose production is limited by nitrate and nitrite concentrations in fens.Nitrogen, along with phosphorus, controls how fertile a wetland is. ==== Phosphorus ==== Almost all of the phosphorus that arrives in a wetland does so through sediments or plant litter from other ecosystems. Along with nitrogen, phosphorus limits wetland fertility. Under basic conditions like those found in extremely rich fens, calcium will bind to phosphate anions to make calcium phosphates, which are unavailable for uptake by plants. Mosses also play a considerable role in aiding plants in phosphorus uptake by decreasing soil phosphorus stress and stimulating phosphatase activity in organisms found below the moss cover. Helophytes have been shown to bolster phosphorus cycling within fens, especially in fen reestablishment, due to their ability to act as a phosphorus sink, which prevents residual phosphorus in the fen from being transferred away from the it. Under normal conditions, phosphorus is held within soil as dissolved inorganic phosphorus, or phosphate, which leaves trace amounts of phosphorus in the rest of the ecosystem.Iron is important in phosphorus cycling within fens. Iron can bind to high levels of inorganic phosphate within the fen, leading to a toxic environment and inhibition of plant growth. In iron-rich fens, the area can become vulnerable to acidification, excess nitrogen and potassium, and low water levels. Peat soils play a role in preventing the bonding of irons to phosphate by providing high levels of organic anions for iron to bind to instead of inorganic anions such as phosphate. === Bog-rich fen gradient === Bogs and fens can be thought of as two ecosystems on a gradient from poor to rich, with bogs at the poor end, extremely rich fens at the rich end, and poor fens in between. In this context, "rich" and "poor" refer to the species richness, or how biodiverse a fen or bog is. The richness of these species is strongly influenced by pH and concentrations of calcium and bicarbonate. These factors assist in identifying where along the gradient a particular fen falls. In general, rich fens are minerotrophic, or dependent on mineral-rich groundwater, while bogs are ombrotrophic, or dependent on precipitation for water and nutrients. Poor fens fall between these two. ==== Rich fens ==== Rich fens are strongly minerotrophic; that is, a large proportion of their water comes from mineral-rich ground or surface water. Fens that are more distant from surface waters such as rivers and lakes, however, have been shown to be more rich than fens that are connected. This water is dominated by calcium and bicarbonate, resulting in a slightly acidic to slightly basic pH, which is characteristic of rich fens. These conditions promote high biodiversity. Within rich fens, there is a large amount of variability. The richest fens are the extreme rich (marl) fens, where marl deposits are often build up. These are often pH 7 or greater. Rich and intermediate rich fens are generally neutral to slightly acidic, with a pH of approximately 7 to 5. Rich fens are not always very productive; at high calcium concentrations, calcium ions bind to phosphate anions, reducing the availability of phosphorus and decreasing primary production. Rich bogs with limited primary production can stabilize with the accumulation of mosses and mycorrhiza, which promote phosphorus cycling and can support the growth of new vegetation and bacteria. Brown mosses (family Amblystegiaceae) and sedges (genus Carex) are the dominant vegetation. However, an accumulation of mosses such as Sphagnum can lead to the acidification of the rich fen, potentially converting it into a poor fen. Compared to poor fens, rich fens have higher concentrations of bicarbonate, base cations (Na+, Ca2+, K+, Mg2+), and sulfate. ==== Poor fens ==== Poor fens are in many ways an intermediate between rich fens and bogs. Hydrologically, they are more alike to rich fens than to bogs, but in terms of vegetation composition and chemistry, they are more similar to bogs than rich fens. They are much more acidic than their rich counterparts, with a pH of approximately 5.5 to 4. Peat in poor fens tends to be thicker than that of rich fens, which cuts off vegetation access to the mineral-rich soil underneath. In addition, the thicker peat reduces the influence of mineral-rich groundwater that buffers the pH. This makes the fen more ombrotrophic, or dependent on nutrient-poor precipitation for its water and nutrients. Poor fens may also form in areas where the groundwater supplying the fen flows through sediments that don't dissolve well or have low buffering capacity when dissolved. Species richness tends to be lower than that of rich fens but higher than that of bogs. Poor fens, like bogs, are dominated by Sphagnum mosses, which acidify the fen and decrease nutrient availability. == Threats == One of the many threats that fens face is conversion to agricultural lands. Where climates are suitable, fens have been drained for agricultural use alongside crop production, grazing, and hay making. Draining a fen directly is particularly damaging because it lowers the water table. A lower water table can increase aeration and dry out peat, allowing for aerobic decomposition or burning of the organic matter in peat. Draining a fen indirectly by decreasing its water supply can be just as damaging. Disrupting groundwater flow into the fen with nearby human activities such as quarrying or residential development changes how much water and nutrients enter the fen. This can make the fen more ombrotrophic (dependent on precipitation), which results in acidification and a change in water chemistry. This has a direct impact on the habitat of these species and many signature fen species disappear.Fens are also threatened by invasive species, fragmentation, peat cutting, and pollution. Non-native invasive species, such as the common buckthorn in North America, can invade fens and outcompete rare fen species, reducing biodiversity. Habitat fragmentation threatens fen species, especially rare or endangered species that are unable to move to nearby fens due to fragmentation. Peat cutting, while much more common in bogs, does happen in fens. Peat cut from fens has many uses, including burning as a fuel. Pollutants can alter the chemistry of fens and facilitate invasion by invasive species. Common pollutants of fens include road salts, nutrients from septic tanks, and runoff of agricultural fertilizers and pesticides. == Use of term in literature == Shakespeare used the term "fen-sucked" to describe the fog (literally: rising from marshes) in King Lear, when Lear says "Infect her beauty, You fen-sucked fogs drawn by the powerful sun, To fall and blister." == Images == == See also == === Specific fens === == References == === Citations === === General bibliography === == External links == Media related to Fens at Wikimedia Commons

Landforms

List of fen plants

The following is a list of plant species to be found in a north European fen habitat with some attempt to distinguish between reed bed relicts and the carr pioneers. However, nature does not come in neat compartments so that for example, the odd stalk of common reed will be found in carr. == In pools == Beaked sedge; Carex rostrata Whorl grass; Catabrosa aquatica Needle spike-rush; Eleocharis acicularis Northern spike-rush; Eleocharis austriaca Sweet grasses; Glyceria species. Common reed; Phragmites australis Swamp meadow grass; Poa palustris == In typical fen == Flat sedge; Blysmus compressus Great fen sedge; Cladium mariscus Lesser tufted sedge; Carex acuta Lesser pond sedge; Carex acutiformis Davall's sedge; Carex davalliana Dioecious sedge; Carex dioica Brown sedge; Carex disticha Tufted sedge; Carex elata Slender sedge; Carex lasiocarpa Flea sedge; Carex pulicaris Greater pond sedge; Carex riparia Common spike-rush; Eleocharis palustris Few-flowered spike-rush; Eleocharis quinqueflora Slender spike-rush; Eleocharis uniglumis Broad-leaved cotton sedge; Eriophorum latifolium Reed sweet-grass; Glyceria maxima Yellow flag iris; Iris pseudacorus Brown bog [sic] rush; Schoenus ferrugineus == In fen carr == Narrow small-reed; Calamagrostis stricta Purple small-reed; Calamagrostis canescens Tussock sedge; Carex paniculata Cyperus sedge; Carex pseudocyperus Wood club rush; Scirpus sylvaticus == References == Rose, F. Grasses, Sedges, Rushes and Ferns of the British Isles and north-western Europe (1989) ISBN 0-670-80688-9

Landforms

Flark

A flark is a depression or hollow within a bog. Flarks typically occur as a series of parallel depressions, separated by intervening ridges known as strings.Early theories suggested that flarks were formed by frost heaving, but flarks have since been found in areas where frost heaving does not occur. Flarks are now thought to form when the peat that forms the base of the bog becomes so thick that it slides downslope due to its own weight. Irregularities in the underlying terrain halt the slide of the peat, causing flarks to form downslope from the obstruction as the downslope peat tears away from the portion of the peat mass held back by the underlying obstruction. Another theory suggests that flarks are formed by areas within the bog which experience accelerated rates of decay, causing depressions in the bog. == References ==

Landforms

Flat (landform)

A flat is a relatively level surface of land within a region of greater relief, such as hills or mountains, usually used in the plural. The term is often used to name places with such features, for example, Yucca Flat or Henninger Flats. Flat is also used to describe other level geographic areas as mud flats or salt flats. == See also == Glade – Open area within a woodland Dry lake – Basin or depression that formerly contained a standing surface water body == References ==

Landforms

Fluting (geology)

In the earth sciences, the terms fluting and flute have very different meanings in its subdisciplines of geomorphology, glaciology, sedimentology, and speleology. == Geomorphology == In geomorphology, a flute is a narrow, shallow channel that runs nearly vertically down the face of a rock surface. It is formed by the weathering and erosion of the rock surface. Correspondingly, fluting is the erosional process by which a well-jointed coarse-grained rock, such as granite or gneiss, surface develops a set of flutes. The includes the formation of small-scale ridges and depressions by wave action. == Glaciology == For the main article about glacial flutes, please see Flute (glacial). In glaciology, flutes are narrow, elongated, straight, parallel ridges generally consisting of till, but sometimes composed of sand or silt/clay. Flutes typically reach a height of only a few meters or less, but some may reach heights of 10 meters (33 ft), and up to 100 meters (330 ft) in length. Flutes are oriented parallel to the direction of ice movement. They are formed when boulders become lodged on the glacial till floor by basal melting and can no longer be moved by the passing glacial ice and the resulting deformation of the till bed.A fluted moraine, also called a fluted moraine surface, is a glacial moraine whose surface exhibits parallel ridges, glacial flutes. They are typically tens of centimeters to a few meters in width and height, and tens of meters in length. The long axes of the flutes are parallel to the flow direction of the glacier. Fluted moraines mainly developed in till surfaces on land, but some have been found in shallow glacimarine settings.Finally, in glaciology, fluting is used in older publications for smooth, deep, gutterlike channels or furrows cut by glaciers into the stoss side of a rocky hill obstructing its advance. Fluting is larger than glacial grooves and do not extend around the hill to its lee side. == Sedimentology == For the main article about the sedimentary structures known as flutes and flute casts, please see Sole markings. In sedimentology, a flute is a primary sedimentary structure consisting of a discontinuous scoop-shaped, spatulate, or lingulate depression or groove. Flutes typically range from 5–50 cm (2.0–19.7 in), in width, from 1–20 cm (0.39–7.87 in) and in depth, and from a few centimeters up to rarely 10 in (25 cm) in depth. They exhibit a steep or abrupt upcurrent end where their depth usually is the greatest. A flute’s long axis is typically parallel to the current. They are typically created by the scouring action of a turbulent, sediment-laden current of water flowing over a muddy bottom. The process by which a flute is formed by the cutting or scouring action of a current of water is often called fluting. After their formation, these types of flutes are often preserved by being filled by sandy or silty sediment to form flute casts, which are infrequently also called fluting. == Speleology == In speleology, flutes are grooves in the walls of a cave that are formed by the dissolution of carbonate rocks of cave walls by descending water. They are typically found in the walls of vertical cave shafts. == References ==

Landforms

Gap (landform)

A gap is a geological formation that is a low point or opening between hills or mountains or in a ridge or mountain range. It may be called a col, notch, pass, saddle, water gap, or wind gap. Geomorphologically, a gap is most often carved by water erosion from a freshet, stream or a river. Gaps created by freshets are often, if not normally, devoid of water through much of the year, their streams being dependent upon the meltwaters of a snow pack. Gaps sourced by small springs will generally have a small stream excepting perhaps during the most arid parts of the year. Water gaps of necessity often cut entirely through a barrier range and riverine gaps may create canyons such as the riverine gaps of the Danube River, Lehigh River Gorge, the Colorado River's Grand Canyon and the Genesee River. Such cuttings may expose millennia of strata in the local rock column writing the geologic record. == References ==

Landforms

Glen

A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Whittow defines it as a "Scottish term for a deep valley in the Highlands" that is "narrower than a strath". The word is Goidelic in origin: gleann in Irish and Scottish Gaelic, glion in Manx. The designation "glen" also occurs often in place names. == Etymology == The word is Goidelic in origin: gleann in Irish and Scottish Gaelic, glion in Manx. In Manx, glan is also to be found meaning glen. It is cognate with Welsh glyn.Examples in Northern England, such as Glenridding, Westmorland, or Glendue, near Haltwhistle, Northumberland, are thought to derive from the aforementioned Cumbric cognate, or another Brythonic equivalent. This likely underlies some examples in Southern Scotland.As the name of a river, it is thought to derive from the Irish word glan meaning clean, or the Welsh word gleindid meaning purity. An example is the Glens of Antrim in Northern Ireland where nine glens radiate out from the Antrim plateau to the sea along the coast between Ballycastle and Larne. == Places == The designation "glen" also occurs often in place names such as Great Glen and Glenrothes in Scotland; Glendalough, Glenswilly, Glen of Aherlow, Glen of Imaal and the Glens of Antrim in Ireland; Glenn Norman in Canada; Glendale, Glen Ellen and Klamath Glen in California, Glenview in Illinois, and Glenrock in Wyoming; Glenview, Glen Waverley, Glen Eira, Glengowrie, Glen Huntly and Glen Forrest in Australia; and Glendowie, Glen Eden and Glen Innes in New Zealand.In the Finger Lakes region of New York State, the southern ends of Seneca Lake and Cayuga Lake in particular are etched with glens, although in this region the term "glen" refers most frequently to a narrow gorge, as opposed to a wider valley or strath. The steep hills surrounding these lakes are filled with loose shale from glacial moraines. This material has eroded over the past 10,000 years to produce rocky glens (e.g., Watkins Glen, Fillmore Glen State Park and Treman State Parks) and waterfalls (e.g., Taughannock Falls) as rainwater has flowed down toward the lakes below. == See also == High valley – Valley in the upper third of a mountain range Strath – Large valley == References ==

Landforms

Grotto

A grotto is a natural or artificial cave used by humans in both modern times and antiquity, and historically or prehistorically. Naturally occurring grottoes are often small caves near water that are usually flooded or often flooded at high tide. Sometimes, artificial grottoes are used as garden features. The Grotta Azzurra at Capri and the grotto at Tiberius' Villa Jovis in the Bay of Naples are examples of popular natural seashore grottoes. Whether in tidal water or high up in hills, grottoes are generally made up of limestone geology, where the acidity of standing water has dissolved the carbonates in the rock matrix as it passes through what were originally small fissures. == Etymology == The word grotto comes from Italian grotta, Vulgar Latin grupta, and Latin crypta ("a crypt"). It is also related by a historical accident to the word grotesque. In the late 15th century, Romans accidentally unearthed Nero's Domus Aurea on the Palatine Hill, a series of rooms, decorated with designs of garlands, slender architectural framework, foliage, and animals. The rooms had sunk underground over time. The Romans who discovered this historical monument found it very strange, partly because it was uncovered from an "underworld" source. This led the Romans of that era to give it the name grottesca, from which came the French grotesque. == Antiquity == Grottoes were very popular in Greek and Roman culture. Spring-fed grottoes were a feature of Apollo's oracles at Delphi, Corinth, and Clarus. The Hellenistic city of Rhodes was designed with rock-cut artificial grottoes incorporated into the city, made to look natural. At the great Roman sanctuary of Praeneste south of Rome, the oldest portion of the primitive sanctuary was situated on the second lowest terrace, in a grotto in the natural rock where a spring developed into a well. According to tradition, Praeneste's sacred spring had a native nymph, who was honored in a grotto-like watery nymphaeum. == Cellars in Ticino == In Ticino, the Italian-speaking part of Switzerland, grottoes were places where wine and food were stored and preserved. They were built by exploiting the morphology of rocks and boulders, to create rooms with a cool climate suitable for food, particularly milk and cheese, as well as potatoes, sausages, and wine storage.The importance of these cellars is demonstrated in their number; for example, there are 40 grotti in Maggia, no fewer in Moghegno, and about 70 in Cevio behind Case Franzoni. Some grotti have been opened to the public, as in Avegno, but most have lost their original character as they became rustic restaurants which serve basic local food and drink. A true grotto is dug out under a rock or between two boulders, where subterranean air currents keep the room cool. Often a grotto had a second floor with another one or two rooms for the fermentation cask and tools of the vintage. In front of the grotto were a table and benches of stone, where the farmers could rest and refresh themselves.: 18  == Garden grottoes == The popularity of artificial grottoes introduced the Mannerist style to Italian and French gardens of the mid-16th century. Two famous grottoes in the Boboli Gardens of Palazzo Pitti were begun by Vasari and completed by Ammanati and Buontalenti between 1583 and 1593. One of these grottoes originally housed the Prisoners of Michelangelo. Before the Boboli grotto, a garden was laid out by Niccolò Tribolo at the Medici Villa Castello, near Florence. At Pratolino, in spite of the dryness of the site, there was a Grotto of Cupid (surviving), with water tricks for the unsuspecting visitor. The Fonte di Fata Morgana ("Fata Morgana's Spring") at Grassina, not far from Florence, is a small garden building, built in 1573–74 as a garden feature in the extensive grounds of the Villa "Riposo" (rest) of Bernardo Vecchietti. It is decorated with sculptures in the Giambolognan manner. The outsides of garden grottoes are often designed to look like an enormous rock, a rustic porch, or a rocky overhang. Inside, they are decorated as a temple or with fountains, stalactites, and imitation gems and shells (sometimes made in ceramic); herms and mermaids, mythological subjects suited to the space; and naiads, or river gods whose urns spilled water into pools. Damp grottoes were cool places to retreat from the Italian sun, but they also became fashionable in the cool drizzle of the Île-de-France. In the Kuskovo Estate, there is the Grotto Pavilion, built between 1755-61. Grottoes could also serve as baths; an example of this is at the Palazzo del Te, in the 'Casino della Grotta', where a small suite of intimate rooms is laid out around a grotto and loggetta (covered balcony). Courtiers once bathed in the small cascade that splashed over the pebbles and shells encrusted in the floor and walls. Grottoes have also served as chapels, or at Villa Farnese at Caprarola, a little theater designed in the grotto manner. They were often combined with cascading fountains in Renaissance gardens. The grotto designed by Bernard Palissy for Catherine de' Medici's château in Paris, the Tuileries, was renowned. There are also grottoes in the gardens designed by André Le Nôtre for Versailles. In England, an early garden grotto was built at Wilton House in the 1630s, probably by Isaac de Caus. Grottoes were suitable for less formal gardens too. Pope's Grotto, created by Alexander Pope, is almost all that survives of one of the first landscape gardens in England, at Twickenham. Pope was inspired after seeing grottoes in Italy during a visit there. Efforts are underway to restore his grotto. There are grottoes in the landscape gardens of Painshill Park, Stowe, Clandon Park, and Stourhead. Scott's Grotto is a series of interconnected chambers, extending 67 ft (20 metres) into the chalk hillside on the outskirts of Ware, Hertfordshire. Built during the late 18th century, the chambers and tunnels are lined with shells, flints, and pieces of colored glass. The Romantic generation of tourists might not actually visit Fingal's Cave, on the remote isle of Staffa in the Scottish Hebrides, but they have often heard of it, perhaps through Felix Mendelssohn's "Hebrides Overture", better known as "Fingal's Cave", which was inspired by his visit. In the 19th century, when miniature Matterhorns and rock gardens became fashionable, a grotto was often found, such as at Ascott House. In Bavaria, Ludwig's Linderhof contains an abstraction of the grotto under Venusberg, which is figured in Wagner's Tannhäuser. Although grottoes have largely fallen from fashion since the British Picturesque movement, architects and artists occasionally try to redefine the grotto in contemporary design works. Such examples include Frederick Kiesler's Grotto of Meditation for New Harmony (1964), ARM'st post-modern Storey Hall (1995), Aranda/Lasch's Grotto Concept, (2005), Callum Moreton's Grotto pavilion (2010), and Antonino Cardillo's Grottoes series (2013–2016). == Religious grottoes == Today, artificial grottoes are purchased and built for ornamental and devotional purposes. They are often used as shrines in which to place statues of saints, particularly the Virgin Mary, in outdoor gardens. Many Roman Catholics visit a grotto where Bernadette Soubirous saw apparitions of Our Lady of Lourdes. Numerous garden shrines are modeled after these apparitions. They can commonly be found displayed in gardens and churches, among other places (see Lourdes grotto). The largest grotto is believed to be the Grotto of the Redemption in West Bend, Iowa. == Gallery == == See also == Cave Architecture of cathedrals and great churches Blue Grotto, former underground wine storage vaults in the anchorages under the Brooklyn Bridge, on the Manhattan side Caves of Hercules Grotto-heavens, Chinese religious usage associated with Daoist religion Karst Shell grotto Tunnels in popular culture == Notes == == Further reading == Jackson, Hazelle (2001). Shell Houses and Grottoes. England: Shire Books). Traces the development of the grotto in Italy during the Renaissance and its popularity in the UK from the eighteenth century to the present. Includes gazetteer of UK grottoes. Jones, B. (1953). Follies and Grottoes. London. Miller, Naomi (1982). Heavenly Caves: Reflections on the Garden Grotto. New York: Braziller. Traces the development of the grotto from Antiquity to modern times.

Landforms

Gypsum cave

A gypsum cave is a natural karstic formation in gypsum. Gypsum karst is very rare. It depends on deposits of gypsum or anhydrite, often also called alabaster. Chemically it is calcium sulfate, CaSO4. Gypsum caves can be found in several places on earth, including: Optymistychna Cave in Ukraine, considered the longest gypsum cave at 232 km Orda Cave underneath the Western Ural Mountains, with 5.1km length, including 4.8km underwater Cuevas de Sorbas in Almeria, SpainCaves noted for large scale gypsum speleothems include: Cave of the Crystals in Chihuahua, Mexico Lechuguilla Cave in New Mexico, US == References == == Related pages == Gypsum Karst == External links == World's longest gypsum caves compiled

Landforms

Heath

A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler and damper climate. Heaths are widespread worldwide but are fast disappearing and considered a rare habitat in Europe. They form extensive and highly diverse communities across Australia in humid and sub-humid areas where fire regimes with recurring burning are required for the maintenance of the heathlands. Even more diverse though less widespread heath communities occur in Southern Africa. Extensive heath communities can also be found in the Texas chaparral, New Caledonia, central Chile, and along the shores of the Mediterranean Sea. In addition to these extensive heath areas, the vegetation type is also found in scattered locations across all continents, except Antarctica. == Characteristics == Heathland is favoured where climatic conditions are typically hard and dry, particularly in summer, and soils acidic, of low fertility, and often sandy and very free-draining; a mire may occur where drainage is poor, but usually is only small in extent. Heaths are dominated by low shrubs, 20 centimetres (8 in) to 2 metres (7 feet) tall. Heath vegetation can be extremely plant-species rich, and heathlands of Australia are home to some 3,700 endemic or typical species in addition to numerous less restricted species. The fynbos heathlands of South Africa are second only to tropical rainforests in plant biodiversity with over 7,000 species. In marked contrast, the tiny pockets of heathland in Europe are extremely depauperate with a flora consisting primarily of heather (Calluna vulgaris), heath (Erica species) and gorse (Ulex species). The bird fauna of heathlands are usually cosmopolitan species of the region. In the depauperate heathlands of Europe, bird species tend to be more characteristic of the community, and include Montagu's harrier and the tree pipit. In Australia the heathland avian fauna is dominated by nectar-feeding birds such as honey-eaters and lorikeets, although numerous other birds from emus to eagles are also common in Australian heathlands. The birds of the South African fynbos include sunbirds, warblers and siskins. Heathlands are also an excellent habitat for insects including ants, moths, butterflies and wasps; many species are restricted entirely to it. One such example of an organism restricted to heathland is the silver-studded blue butterfly, Plebejus argus. == Anthropogenic heaths == Anthropogenic heath habitats are a cultural landscape that can be found worldwide in locations as diverse as northern and western Europe, the Americas, Australia, New Zealand, Madagascar and New Guinea. These heaths were originally made or expanded by centuries of human clearance of the natural forest and woodland vegetation, by grazing and burning. In some cases this clearance went so far that parts of the heathland have given way to open spots of pure sand and sand dunes, with a local climate that, even in Europe, can rise to temperatures of 50 °C (122 °F) in summer, drying the sand spot bordering the heathland and further raising its vulnerability for wildfires. Referring to heathland in England, Oliver Rackham says, "Heaths are clearly the product of human activities and need to be managed as heathland; if neglected they turn into woodland".The conservation value of these man-made heaths has become much more appreciated due to their historical cultural value as habitats; consequently, most heathlands are protected. However they are also threatened by tree incursion because of the discontinuation of traditional management techniques, such as grazing and burning, that mediated the landscapes. Some are also threatened by urban sprawl. Anthropogenic heathlands are maintained artificially by a combination of grazing and periodic burning (known as swailing), or (rarely) mowing; if not so maintained, they are rapidly recolonised by forest or woodland. The recolonising tree species will depend on what is available as the local seed source, and thus it may not reflect the natural vegetation before the heathland became established. == In literature == The heath features prominently in: King Lear, by William Shakespeare Wuthering Heights, by Emily Brontë The Return of the Native, by Thomas Hardy Ethan Frome, by Edith Wharton == Gallery == == See also == Bolster heath Chalk heath Garrigue Maquis shrubland Matorral Scrubland == References == == External links == The Countryside Agency information on types of open land Origin of the word 'heath'

Landforms

Highland

Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally, upland refers to a range of hills, typically from 300 m (980 ft) up to 500–600 m (1,600–2,000 ft), while highland is usually reserved for ranges of low mountains. However, the two terms are sometimes interchangeable. == Highlands internationally == Probably the best-known area officially or unofficially referred to as highlands in the Anglosphere is the Scottish Highlands in northern Scotland, the mountainous region north and west of the Highland Boundary Fault. The Highland council area is a local government area in the Scottish Highlands and Britain's largest local government area. Other highland or upland areas reaching 400-500 m or higher in the United Kingdom include the Southern Uplands in Scotland, the Pennines, North York Moors, Dartmoor and Exmoor in England, and the Cambrian Mountains in Wales. Many countries and regions also have areas referred to as highlands. These include parts of Afghanistan, Tibet, Ethiopia, Canada, Kenya, Eritrea, Yemen, Ghana, Nigeria, Papua New Guinea, Syria, Turkey and Cantabria.Synonymous terms used in other countries include high country, used in New Zealand, New South Wales, Victoria, Tasmania and Southern Queensland in Australia, and parts of the United States (notably Western North Carolina), highveld, used in South Africa and Roof of the World, used for Tibet. The central Afghan highlands are in the center of Afghanistan, mostly located between 2,000 and 3,000 m above sea level. They have a very cold winter, and a short and cool summer. These highlands have mountain pastures during summer (sardsīr), watered by many small streams and rivers. There are also pastures available during winter in the neighboring warm lowlands (garmsīr), which makes the region ideal for seasonal transhumance. The highlands in Australia are often above the elevation of 500 m. These areas often receive snowfall in winter. Most of the highlands lead up to large alpine or sub-alpine mountainous regions such as the Australian Alps, Snowy Mountains, Great Dividing Range, Northern Tablelands and Blue Mountains. The most mountainous region of Tasmania is the Central Highlands area, which covers most of the central-western parts of the state. Many of these areas are highly elevated alpine regions. The Ozarks cover nearly 120,000 square kilometres (46,000 sq mi), making it the most extensive highland region between the Appalachians and Rockies. This region contains some of the oldest rocks in North America. The spine of the mountains stretches across the island of New Guinea, forming the densely populated highlands of Papua New Guinea, and the Highland Papua, Indonesia. The Central Highlands of Sri Lanka are rain forests, where the elevation reaches 2,500 m (8,200 ft) above sea level. The Sri Lanka montane rain forests represent the montane and submontane moist forests above 1,000 m (3,300 ft) in the central highlands and in the Knuckles mountain range. Half of Sri Lanka's endemic flowering plants and 51 percent of the endemic vertebrates are restricted to this ecoregion. The highlands of Iceland cover about 40% of the country and are mostly inhospitable to humans. They are generally considered to be any land above 500 m. The mountainous natural region of the Thai highlands is found in Northern Thailand. The Cameron Highlands is a highland area and hill station in Northern Malaysia. Shillong in India in the state of Meghalaya is a hill station that is surrounded by highlands. Officers of the British Raj referred to Shillong as "The Scotland of the East". == Other planets == Highland continents—or terrae—are areas of topographically unstable terrain, with high peaks and valleys. They resemble highlands on Earth, but the term is applied to much larger areas on other planets. They can be found on Mercury, Venus, Mars, and the Moon. == See also == Highlander (disambiguation) Plateau == References ==

Landforms

Hill chain

A hill chain, sometimes also hill ridge, is an elongated line of hills that usually includes a succession of more or less prominent hilltops, domed summits or kuppen, hill ridges and saddles and which, together with its associated lateral ridges and branches, may form a complex topographic structure. It may occur within a hill range, within an area of low rolling hill country or on a plain. It may link two or more otherwise distinct hill ranges. The transition from a hill chain to a mountain chain is blurred and depends on regional definitions of a hill or mountain. For example, in the UK and Ireland a mountain must officially be 600 m (2,000 ft) or higher, whereas in North America mountains are often (unofficially) taken as being 1,000 ft (300 m) high or more.The chain-like arrangement of hills in a chain is a consequence of their collective formation by mountain building forces or ice age earth movements. Hill chains generally have a uniform geological age, but may comprise several types of rock or sediment. Hill chains normally form a watershed. They are crossed by roads that often use a natural saddle in the terrain. == Examples == the Argonne hill chain, in France. the Fläming south of Berlin in Germany. the Malvern Hills in central England. the ridge between the Taunus and Vogelsberg, which lies south of Giessen and forms the watershed between the Lahn valley and the Wetterau in Germany. == See also == Mountain chain == References == == Literature == Stebbing, W.P.D. (1940). "Some early references to geology from the sixteenth century onwards". Proceedings of the Geologists' Association. 51 (2): 49–63. Bünz, Enno (2008). Ostsiedlung und Landesausbau in Sachsen. Leipzig: Leipziger Universitätsverlag. Leggiere, Michael V. (2007). The Fall of Napoleon. Vol. 1. Cambridge University Press. == External links ==

Landforms

Hillock

A hillock or knoll is a small hill, usually separated from a larger group of hills such as a range. Hillocks are similar in their distribution and size to small mesas or buttes. This particular formation occurs often in Great Britain and China. A similar type of landform in the Scandinavian countries goes by the name ”kulle” or ”bakke” (depending on the country) and is contrary to the above phenomena formed when glaciers polish down hard, crystalline bedrock of gneiss or granites, leaving a rounded rocky hillock with sparse vegetation.One of the most famous knolls is the one near John F. Kennedy's point of assassination, the grassy knoll, in Dealey Plaza of downtown Dallas, Texas. It is the source of many prominent conspiracy theories regarding the circumstances of his assassination. A "blind knoll" is either hidden or not readily apparent to those driving vehicles. There are road signs that warn of this, advising drivers to slow down. == Gallery == == See also == Crug (disambiguation) Mound – Artificial heaped pile of earth, gravel, sand, rocks, or debris Mountain – Large natural elevation of the Earth's surface Hügelland – Landscape consisting of low, rolling hills == Notes ==

Landforms

Huerta

A huerta (Spanish: [ˈweɾta]) or horta (Catalan: [ˈɔɾta], Portuguese: [ˈɔɾtɐ]), from Latin hortus, "garden", is an irrigated area, or a field within such an area, common in Spain and Portugal, where a variety of vegetables and fruit trees are cultivated for family consumption and sale. Typically, individual huertas belong to different people; they are located around rivers or other water sources because of the amount of water required, which is usually provided through small canals (acequias). They are a kind of market garden. == Alternate definitions == Elinor Ostrom has defined huertas as "well-demarked irrigation areas surrounding or near towns" (emphasis added). == See also == Acequia Irrigation district Horta of Valencia == References == == Bibliography == Glick, Thomas F. 1970. Irrigation and Society in Medieval Valencia. Cambridge, MA: Harvard University Press. Maass, Arthur, and Raymond Lloyd Anderson. 1978. ...and the Desert Shall Rejoice: Conflict, Growth and Justice in Arid Environments. Cambridge, MA: MIT Press. ISBN 9780262131346 Ostrom, Elinor (2015 [1990]). "Huerta Irrigation Institutions." Pp.69-82 in Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge, UK: Cambridge University Press. ISBN 9781107569782

Landforms

Hügelkultur

Hügelkultur (German pronunciation: [ˈhyːɡl̩kʊlˌtuːɐ̯]), literally mound bed or mound culture is a horticultural technique where a mound constructed from decaying wood debris and other compostable biomass plant materials is later (or immediately) planted as a raised bed. Adopted by permaculture advocates, it is suggested the technique helps to improve soil fertility, water retention, and soil warming, thus benefitting plants grown on or near such mounds. == History == Hügelkultur is a German word meaning mound culture or hill culture. Though the technique is alleged to have been practiced in German and Eastern European societies for hundreds of years, the term was first published in a 1962 German gardening booklet by Herrman Andrä. Inspired by the diversity of plants growing in a pile of woody debris in his grandmother's garden, Andrä promoted "mound culture" as opposed to "flatland culture". This was also posited as an easy way to utilise woody debris without burning, which was illegal. Andrä appears to have been influenced by Rudolf Steiner's biodynamic agriculture. Steiner explained his biodynamic philosophy as developed through meditation and clairvoyance, rejecting scientific inquiry on the grounds that his methods were “true and correct unto themselves.” Andrä quotes a 1924 lecture on biodynamics by Steiner, which describes mixing of soil with composting or decaying material in earthen hillocks. Joined by author Hans Beba, another German gardener, "Hill Culture - the horticultural method of the future" was revised and republished several times in the 1970s and 1980s.The technique was later adopted and developed by Sepp Holzer, an Austrian permaculture advocate. More recent permaculture advocates such as Paul Wheaton strongly promote Hügelkultur beds as a perfect permaculture design. == Use == === Construction === In its basic form, mounds are constructed by piling logs, branches, plant waste, compost and additional soil directly on the ground. The pile has the form of a pyramid. The sides of the two slopes both have a grade of between 65 and 80 degrees. The beds are usually about 3 by 6 feet (0.91 by 1.83 m) in area and about 3 feet (0.91 m) high. However, this height reduces as decomposition progresses.When positioned on sloped terrain, the beds need to be placed on contour, or put at an angle to the hillside (rather than having them parallel to it). This makes sure the beds do not receive unequal amounts of water. In most cases, it is useful to have the beds positioned against the prevailing wind direction. The raised bed can form light-duty swales, circles and mazes. Mounds may also be made from alternating layers of wood, sod, compost, straw, and soil. Although their construction is straightforward, planning is necessary to prevent steep slopes that would result in erosion.In his book Desert or Paradise: Restoring Endangered Landscapes Using Water Management, Including Lake and Pond Construction, Holzer describes a method of constructing Hügelkultur which incorporates rubbish such as cardboard, clothes and kitchen waste. He recommends building mounds that are 1 meter (3.3 ft) wide and any length. Mounds are built in a 0.7 meters (2.3 ft) trench in sandy soil, and without a trench if the ground is wet. === Planting === The mound is left to rest for several months before planting, although some advise immediate planting.Anything can be grown on the raised beds, but if the bed will decompose/release its nutrients quickly (so long as it is not made of bulky materials like tree trunks), more demanding crops such as pumpkins, zucchini, cucumbers, cabbages, tomatoes, sweet corn, celery, or potatoes are grown in the first year, after which the bed is used for less demanding crops like beans, peas, and strawberries. === Lifespan === The original German publications described the mounds as having a lifespan of 5–6 years, after which they had to be rebuilt from scratch. == Evidence == As of 2017 there are no peer-reviewed scientific studies available regarding the efficacy of the technique. A few university student projects investigate Hügelkultur but have not been published in scientific journals.One small scale and short term student project investigated the Hügelkultur method as a potential use for yard trimmings waste, and also if lima beans, kale and okra planted on a Hügelkultur mound showed any signs of nutrient deficiency compared to a non-raised control bed. It was found that over 11 tons of yard trimmings were used in the mound, and no evidence of macronutrient deficiency could be detected in the crops in the short term. Indeed, despite concerns that incorporation of large quantities of high carbon woody matter would lead to nitrogen immobilization and hence nitrogen deficiency in the crop, a higher level of nitrogen was found in the raised bed. However, the micronutrient iron was lower relative to the control bed. The author speculated that no nitrogen deficiency occurred since the roots of the plants did not penetrate past the superficial layers of the mound into the deeper wood-containing region.A student thesis investigated the water holding capacity of Hügelkultur beds and whether the technique could be useful to prevent karst rocky desertification in China. Over 3 months of measurements, water concentration in hügel mounds remained high. Samples from hügel sites contained almost twice as much water as those from flat control plots. It was suggested that 1 ha (2+1⁄2 acres) of hügels has 3-10 times more water than a flat plot affected by karst rocky desertification. == Theory == Many publications and websites advocate the technique based on personal experience of the authors. Some have criticised the technique as lacking genuine scientific principles, and running counter to the ecological principles of soil building with litterfall.Hügelkultur is said to replicate the natural process of decomposition that occurs on forest floors, however in natural ecosystems wood would be present at the soil surface. Trees that fall in a forest often become nurse logs decaying and providing ecological facilitation to seedlings. As the wood decays, its porosity increases, allowing it to store water like a sponge. The water is slowly released back into the environment, benefiting nearby plants.These beds are also considered beneficial because of the airpockets created by the settling caused by the wood's decomposition. This gives the benefits of tilling, without the destruction of soil microorganisms that come with tilling ("every time you till the soil, you lose 30% of the organic material (microbial soil life is killed, and plants feast on their bodies)"). And, the organic material of the rotting wood also houses beneficial soil microorganisms.Hügelkultur beds are said to be ideal for areas where the underlying soil is of poor quality or compacted. They tend to be easier to maintain due to their relative height above the ground.The decomposition speed of organic material depends on the carbon to nitrogen ratio of the material, among other factors. Wood breaks down relatively slowly because it has one of the highest carbon to nitrogen ratios of all organic matter that is used in composting. If the wood is not processed into smaller pieces with larger surface area to speed up chemical reactions, breakdown is even slower. The decomposition process may, in the short term, take more nitrogen from the soil through microbial activity (nitrogen immobilization), if not enough nitrogen is available. Thus, in the short term, the fertility of the soil may be decreased before, eventually, perhaps after one to two years, the nitrogen level is increased past the original level. Traditionally, therefore, it is said to be advantageous to balance "browns" (e.g. woodchippings) with "greens" (e.g. grass clippings) for efficient composting, and to allow compost to become well-rotted before applying it to a bed, to prevent competition between soil bacteria and plants for nitrogen, which reduces yield. == Criticisms and controversy == === Hügelkultur mounds as solid earthworks === Although Hügelkultur beds can safely retain water in light-duty applications (for example, conserving the moisture of rain that falls on the bed), creating heavy-duty rainwater retention areas behind Hügelkultur beds on contour, to catch surface runoff from surrounding areas, can be dangerous. Some designers conflate the Hügelkultur bed's appearance with that of solid earthworks, but Hügelkultur beds cannot predictably control large amounts of stormwater in the way that solid earthworks can. Whereas embankment dams or the hillsides of swales can be relied on to hold back many thousands of gallons of water for weeks to allow it to seep into the ground, and berms can slow runoff, Hügelkultur beds are different in two ways: earthworks have no buoyant core (whereas Hügelkultur mounds contain logs), and the soil that they are made of is compacted. If fresh or dried timber is used in the bed, it may become buoyant in the water-saturated substrate, bursting from the soil covering and releasing all the sitting water through a breach. This can be an issue for years, until the wood is sufficiently rotten and infused with water. Another consideration is that Hügelkultur beds will degrade, shrinking over time into much lower mounds of soft, rich soil. This means that the retention area will have less depth as time goes on, but it also means that the uncompacted soil will remain a threat to breaching even if the logs become saturated. Some permaculturists have taken mild positions against the "hügel swales" still being promoted by other permaculturists, citing the danger and cross-purposes of Hügelkultur beds and swales. Swales are for long-term installations where perennials - like fruit trees - are grown. Hügelkultur is used for shorter term, more annual crops, as the soil settling that occurs with hugel decomposition is bad for the root system of fruit trees.There is a recorded instance of a breach occurring in a new project. Upon the first rainstorm, the retention areas behind the Hügelkultur beds filled with water and broke through. The released water carried the freshly-buried logs and dirt downhill, smashing a hole in a building being used as a church and filling the space with mud. No injuries were reported. === Overfertilization, contamination of soil and water habitats === Over-fertilized plants are said to have less flavor, and too much nitrogen can be consumed by eating certain plants which have been over-fertilised (e.g., spinach). Advocates state that overfertilization is a risk in the first year if woodchips are used, which will break down too fast. Instead raised beds made with whole logs release nutrients slowly over a period of years. It has been suggested that excessive use of decomposing organic matter in Hügelkultur could leach out and contaminate and disrupt soil and water habitats. == See also == Hotbed Hot container composting Vertical farming == References == == External links == Media related to Category:Hügelkultur at Wikimedia Commons Practical step by step guide to implement hügelkultur raised beds hugelkultur: the ultimate raised garden beds 7 Things to Know About Hugelkultur Gardening Hugelkultur: Composting Whole Trees With Ease

Landforms

Hügelland

Hügelland is a type of landscape consisting of low rolling hills whose topography or surface structure lies between that of a lowland region (plains or river terraces) and that of a more rugged hill range or low mountain range. The term is German and has no exact equivalent in English, but is often translated as "hill country", "hilly terrain", "upland(s)" or "gently undulating" or "rolling country", or "rolling countryside". It is derived from Hügel, a low hill or hillock and appears frequently as a proper name for this type of terrain. The term Hügelland is not unambiguously defined, even in German. For example, on the plains of North Germany, Poland or Hungary it may be applied to terrain with a height variation of just 50 metres, whilst in the Alpine Foreland or in the Voralpen it might refer to terrain with a height difference of at least 100–200 metres. On the other hand, some scholars prefer to define Hügelland by its height above sea level; for example, applying it to terrain between 200 and 500 metres above sea level. == Structure == Structurally and geomorphologically, a Hügelland landscape has a significant proportion of less well-defined components. For example: It is topographically not as clearly defined a mountain or hill range, which is why it usually exhibits variable erosion (the aspects of its slopes facing all points of the compass) and why it rarely has series of parallel watercourses such as those typically created in hilly or mountainous terrain. Settlements may be located either in the valleys or on the heights (which offered sunny sites in winter, sheltered leeward locations and, formerly, better defensive positions); Arable usage is equally diverse - depending on soil type, local climate and groundwater. The formation of the terrain often has geological causes that differ from those of hills and mountains:Hills and mountains are caused by folding along tectonic weaknesses or fault lines, which are then followed by rivers. This results in a parallel pattern, which can be made even more regular through erosion. Hügelland rarely exhibits these properties. When the gently rolling hills of a Hügelland are suitable for agriculture, their small-scale nature is further reinforced, which may result in a colourful succession of mixed forest and open areas with pastures, meadows, arable crops and orchards, divided by hedgerows along the tracks, lanes and embankments. Mixed woodland, hedges, ponds and scattered settlements occur, giving the appearance of a mosaic from the air. == Regions named Hügelland == The regions listed below have Hügelland as part of their proper name. Several also have alternative English-language names. Austria: Mattersburger Hügelland, Burgenland Oststeirisches Hügelland, Styria Germany: Aachener Hügelland, North Rhine-Westphalia Alzeyer Hügelland, Rhineland-Palatinate Angelner Hügelland, Schleswig-Holstein Mittelsächsisches Hügelland, Saxony Nordthüringer Hügelland, Thuringia Ostbraunschweigisches Hügelland, Lower Saxony Schleswig-Holsteinisches Hügelland, Schleswig-Holstein Spalter Hügelland, Bavaria Unterbayerisches Hügelland, Bavaria Switzerland Freiburger Hügelland == Other examples == Austria: Upper Austria: Innviertel, Hausruckviertel Lower Austria: Bucklige Welt, parts of Mostviertel; Weinviertel, Wienerwaldsee South Burgenland SE-Carinthia Germany Baden-Württemberg: Jagst-Ries, Kraichgau Bavaria: Haßlacherbergkette in North-Upper Franconia, Middle Franconia, Upper Swabia Brandenburg/Saxony-Anhalt: Fläming Rhineland-Palatinate: Rhenish Hesse Lower Saxony: Lüneburg Heath Mecklenburg-Vorpommern: Baltic Uplands, Feldberg Lake District, Mecklenburg Switzerland North Rhine-Westphalia: Baumberge and Beckum Hills, Münsterland Saxony: Lower Lusatia, North Saxony Schleswig-Holstein: Holstein Switzerland, Hütten Hills Italy: The Langhe in the Piemont, between Turin and the Ligurian Alps Poland: Pomeranian Lakeland, Prussian-, Baltic Uplands Lower Silesia, Lodz region Switzerland Parts of the Jura Swiss Plateau, Napf Hungary, Romania, Serbia Göcsej, Raabtal, Balaton-South; Buda Hills, Zemplín Slavonia, Batschka, Banat, Siebenbürgen, Dobruja == Similar concepts == An example of Hügelland outside Europe is Rwanda in Africa, whose character is expressed by its French name of Pays de Mille Collines ("Land of a Thousand Hills"). In Sweden the term undulating hilly land (Swedish: bergkullterräng) is used since Sten Rudberg coined the concept in 1960. In the Swedish context this means hilly areas made up of crystalline rocks of the Baltic Shield that are often contrasted with joint valley landscapes, the Sub-Cambrian peneplain and plains with residual hills. In southern Sweden the undulating hilly lands are coterminous with the Sub-Mesozoic hilly peneplains, an ancient surface formed by weathering in warm and humid climates during the Mesozoic. == References ==

Landforms

Intertidal wetland

An intertidal wetland is an area along a shoreline that is exposed to air at low tide and submerged at high tide. This type of wetland is defined by an intertidal zone and includes its own intertidal ecosystems. == Description == The main types of intertidal wetlands are mudflats (e.g., mangrove swamps) and salt marshes. The mangrove swamps are encountered along tropical shores and are characterized by tree vegetation, while salt marshes are mostly found in temperate zones and are mostly grass ecosystems.Intertidal wetlands are commonly encountered in most estuaries. Intertidal wetland ecosystems are amongst the most productive plant communities and often constitute a large part of the estuary areas. == See also == Tidal marsh == References ==

Landforms

Inverted river delta

An inverted river delta is special category of river delta in which the narrow end of the delta emerges on the seafront and the wide end is located further inland, so that with respect to the seafront, the locations of both ends of the delta are inverted. == Explanation == River deltas typically form on flat, coastal floodplains: the narrow end located at the point where a river fans out and deposits sediment in a region extending outward into the body of water which the river empties. In the case of an inverted delta, the delta is located at the waterway's exit from a large, flat valley, yet still inside the valley. The sediment is dropped within the valley and the clear water then exits into a bay or the ocean, so the apex of the delta is at this exit, a configuration said to be inverted from that usually seen. Inverted deltas typically do not last long in geological terms, since they tend to fill up with sediments rather quickly and eventually become normal deltas. == Examples == === The Sacramento-San Joaquin River Delta === A classic example of an inverted river delta is the Sacramento-San Joaquin River Delta, which lies at the confluence of the Sacramento and San Joaquin rivers in California. The water from the rivers that drain the entire, large California Central Valley exit through the Carquinez Strait, a narrow gap in the Coast Range. An inverted river delta exists behind this strait. === The Tagus River === Another example is the delta of the Tagus river in Portugal, although due to sedimentation this delta is now only very partially inverted, with the valley now mostly filled with sediment. It is still about 15 km wide and 25 km long, compared with the 2 km wide exit into the sea, and forms a large lagoon with large and very shallow sand banks which go uncovered during low tides. The delta used to be even bigger thousands of years ago.

Landforms

Karst Topography

Landforms

Karst

Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone, dolomite, and gypsum. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. In regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground.The study of paleokarst (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. == Etymology == The English word karst was borrowed from German Karst in the late 19th century, which entered German much earlier. According to one interpretation, the term is derived from the German name for a number of geological, geomorphological, and hydrological features found within the range of the Dinaric Alps. The range stretches from the northeastern corner of Italy above the city of Trieste, across the Balkan peninsula along the coast of the eastern Adriatic to Kosovo and North Macedonia, where the massif of the Šar Mountains begins. The karst zone is at the northwesternmost section, described in early topographical research as a plateau between Italy and Slovenia. In the local South Slavic languages, all variations of the word are derived from a Romanized Illyrian base (yielding Latin: carsus, Dalmatian: carsus), later metathesized from the reconstructed form *korsъ into forms such as Slovene: kras and Serbo-Croatian: krš, kras. Languages preserving the older, non-metathesized form include Italian: Carso, German: Karst, and Albanian: karsti; the lack of metathesis precludes borrowing from any of the South Slavic languages, specifically Slovene. The Slovene common noun kras was first attested in the 18th century, and the adjective form kraški in the 16th century. As a proper noun, the Slovene form Grast was first attested in 1177.Ultimately, the word is of Mediterranean origin. It has been suggested that the word may derive from the Proto-Indo-European root karra- 'rock'. The name may also be connected to the oronym Kar(u)sádios oros cited by Ptolemy, and perhaps also to Latin Carusardius. == Early studies == Johann Weikhard von Valvasor, a pioneer of the study of karst in Slovenia and a fellow of the Royal Society, London, introduced the word karst to European scholars in 1689 to describe the phenomenon of underground flows of rivers in his account of Lake Cerknica.Jovan Cvijić greatly advanced the knowledge of karst regions, so much that he became known as the "father of karst geomorphology". Primarily discussing the karstic regions of the Balkans, Cvijić's 1893 publication Das Karstphänomen describes landforms such as karren, dolines and poljes. In a 1918 publication, Cvijić proposed a cyclical model for karstic landscape development. Karst hydrology emerged as a discipline in the late 1950s and the early 1960s in France. Previously, the activities of cave explorers, called speleologists, had been dismissed as more of a sport than a science and so the underground karstic caves and their associated watercourses were, from a scientific perspective, understudied. == Development == Karst is most strongly developed in dense carbonate rock, such as limestone, that is thinly bedded and highly fractured. Karst is not typically well developed in chalk, because chalk is highly porous rather than dense, so the flow of groundwater is not concentrated along fractures. Karst is also most strongly developed where the water table is relatively low, such as in uplands with entrenched valleys, and where rainfall is moderate to heavy. This contributes to rapid downward movement of groundwater, which promotes dissolution of the bedrock, whereas standing groundwater becomes saturated with carbonate minerals and ceases to dissolve the bedrock. === Chemistry of dissolution === The carbonic acid that causes karstic features is formed as rain passes through Earth's atmosphere picking up carbon dioxide (CO2), which readily dissolves in the water. Once the rain reaches the ground, it may pass through soil that provides additional CO2 produced by soil respiration. Some of the dissolved carbon dioxide reacts with the water to form a weak carbonic acid solution, which dissolves calcium carbonate. The primary reaction sequence in limestone dissolution is the following: In very rare conditions, oxidation can play a role. Oxidation played a major role in the formation of ancient Lechuguilla Cave in the US state of New Mexico and is presently active in the Frasassi Caves of Italy. The oxidation of sulfides leading to the formation of sulfuric acid can also be one of the corrosion factors in karst formation. As oxygen (O2)-rich surface waters seep into deep anoxic karst systems, they bring oxygen, which reacts with sulfide present in the system (pyrite or hydrogen sulfide) to form sulfuric acid (H2SO4). Sulfuric acid then reacts with calcium carbonate, causing increased erosion within the limestone formation. This chain of reactions is: This reaction chain forms gypsum. == Morphology == The karstification of a landscape may result in a variety of large- or small-scale features both on the surface and beneath. On exposed surfaces, small features may include solution flutes (or rillenkarren), runnels, limestone pavement (clints and grikes), kamenitzas collectively called karren or lapiez. Medium-sized surface features may include sinkholes or cenotes (closed basins), vertical shafts, foibe (inverted funnel shaped sinkholes), disappearing streams, and reappearing springs. Large-scale features may include limestone pavements, poljes, and karst valleys. Mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers, or haystack/eggbox landscapes. Beneath the surface, complex underground drainage systems (such as karst aquifers) and extensive caves and cavern systems may form.Erosion along limestone shores, notably in the tropics, produces karst topography that includes a sharp makatea surface above the normal reach of the sea, and undercuts that are mostly the result of biological activity or bioerosion at or a little above mean sea level. Some of the most dramatic of these formations can be seen in Thailand's Phangnga Bay and at Halong Bay in Vietnam. Calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide. Rivers which emerge from springs may produce tufa terraces, consisting of layers of calcite deposited over extended periods of time. In caves, a variety of features collectively called speleothems are formed by deposition of calcium carbonate and other dissolved minerals. == Hydrology == Farming in karst areas must take into account the lack of surface water. The soils may be fertile enough, and rainfall may be adequate, but rainwater quickly moves through the crevices into the ground, sometimes leaving the surface soil parched between rains. A karst fenster (karst window) occurs when an underground stream emerges onto the surface between layers of rock, cascades some distance, and then disappears back down, often into a sinkhole. Rivers in karst areas may disappear underground a number of times and spring up again in different places, usually under a different name (like Ljubljanica, the river of seven names). An example of this is the Popo Agie River in Fremont County, Wyoming. At a site simply named "The Sinks" in Sinks Canyon State Park, the river flows into a cave in a formation known as the Madison Limestone and then rises again 800 m (1⁄2 mi) down the canyon in a placid pool. A turlough is a unique type of seasonal lake found in Irish karst areas which are formed through the annual welling-up of water from the underground water system.Water supplies from wells in karst topography may be unsafe, as the water may have run unimpeded from a sinkhole in a cattle pasture, through a cave and to the well, bypassing the normal filtering that occurs in a porous aquifer. Karst formations are cavernous and therefore have high rates of permeability, resulting in reduced opportunity for contaminants to be filtered. Groundwater in karst areas is just as easily polluted as surface streams. Sinkholes have often been used as farmstead or community trash dumps. Overloaded or malfunctioning septic tanks in karst landscapes may dump raw sewage directly into underground channels. Geologists are concerned with these negative effects of human activity on karst hydrology which, as of 2007, supplied about 25% of the global demand for drinkable water.The karst topography also poses difficulties for human inhabitants. Sinkholes can develop gradually as surface openings enlarge, but progressive erosion is frequently unseen until the roof of a cavern suddenly collapses. Such events have swallowed homes, cattle, cars, and farm machinery. In the United States, sudden collapse of such a cavern-sinkhole swallowed part of the collection of the National Corvette Museum in Bowling Green, Kentucky in 2014. === Aquifers === == Interstratal karst == Interstratal karst is a karstic landscape which is developed beneath a cover of insoluble rocks. Typically this will involve a cover of sandstone overlying limestone strata undergoing solution. In the United Kingdom for example extensive doline fields have developed at Cefn yr Ystrad, Mynydd Llangatwg and Mynydd Llangynidr in South Wales across a cover of Twrch Sandstone which overlies concealed Carboniferous Limestone, the last-named having been declared a site of special scientific interest in respect of it. == Kegelkarst == Kegelkarst is a type of tropical karst terrain with numerous cone-like hills, formed by cockpits, mogotes, and poljes and without strong fluvial erosion processes. This terrain is found in Cuba, Jamaica, Indonesia, Malaysia, the Philippines, Puerto Rico, southern China, Myanmar, Thailand, Laos and Vietnam. == Pseudokarst == Pseudokarsts are similar in form or appearance to karst features but are created by different mechanisms. Examples include lava caves and granite tors—for example, Labertouche Cave in Victoria, Australia—and paleocollapse features. Mud Caves are an example of pseudokarst. == Salt karst == Salt karst (or 'halite karst') is developed in areas where salt is undergoing solution underground. It can lead to surface depressions and collapses which present a geo-hazard. == Paleokarst == Paleokarst or palaeokarst is a development of karst observed in geological history and preserved within the rock sequence, effectively a fossil karst. There are for example palaeokarstic surfaces exposed within the Clydach Valley Subgroup of the Carboniferous Limestone sequence of South Wales which developed as sub-aerial weathering of recently formed limestones took place during periods of non-deposition within the early part of the period. Sedimentation resumed and further limestone strata were deposited on an irregular karstic surface, the cycle recurring several times in connection with fluctuating sea levels over prolonged periods. == Karst forest == Karst areas tend to have unique types of forests. The karst terrain is difficult for humans to traverse, so that their ecosystems are often relatively undisturbed. The soil tends to have a high pH, which encourages growth of unusual species of orchids, palms, mangroves, and other plants. == Karst areas == The world's largest limestone karst is Australia's Nullarbor Plain. Slovenia has the world's highest risk of sinkholes, while the western Highland Rim in the eastern United States is at the second-highest risk of karst sinkholes.In Canada, Wood Buffalo National Park, NWT contains areas of karst sinkholes.Mexico hosts important karstic regions in the Yucatán Peninsula and Chiapas.The South China Karst in the provinces of Guizhou, Guangxi, and Yunnan provinces is a UNESCO World Heritage Site. == List of terms for karst-related features == Abîme, a vertical shaft in karst that may be very deep and usually opens into a network of subterranean passages Cenote, a deep sinkhole, characteristic of Mexico, resulting from collapse of limestone bedrock that exposes groundwater underneath Doline, also sink or sinkhole, is a closed depression draining underground in karst areas. The name "doline" comes from dolina, meaning "valley", and derives from South Slavic languages. Foibe, an inverted funnel-shaped sinkhole Karst window (also known as a "karst fenster"), a feature where a spring emerges briefly, with the water discharge then abruptly disappearing into a nearby sinkhole Karst spring, a spring emerging from karst, originating a flow of water on the surface Limestone pavement, a landform consisting of a flat, incised surface of exposed limestone that resembles an artificial pavement Losing stream, sinking river or ponornica in South Slavic languages. Polje (karst polje, karst field), a large flat specifically karstic plain. The name "polje" derives from South Slavic languages. Ponor, same as estavelle, sink or sinkhole in South Slavic languages, where surface flow enters an underground system Scowle, porous irregular karstic landscape in a region of England. Turlough (turlach), a type of disappearing lake characteristic of Irish karst. Uvala, a collection of multiple smaller individual sinkholes that coalesce into a compound sinkhole. The term derives from South Slavic languages (many karst-related terms derive from South Slavic languages, entering scientific vocabulary through early research in the Western Balkan Dinaric Alpine karst). == See also == == References == == Further reading == Ford, D.C., Williams, P., Karst Hydrogeology and Geomorphology, John Wiley and Sons Ltd., 2007, ISBN 978-0-470-84996-5 Jennings, J.N., Karst Geomorphology, 2nd ed., Blackwell, 1985, ISBN 0-631-14032-8 Palmer, A.N., Cave Geology, 2nd Printing, Cave Books, 2009, ISBN 978-0-939748-66-2 Sweeting, M.M., Karst Landforms, Macmillan, 1973, ISBN 0-231-03623-X van Beynen, P. (Ed.), Karst management, Springer, 2011, ISBN 978-94-007-1206-5 Vermeulen, J.J., Whitten, T., "Biodiversity and Cultural Property in the Management of Limestone Resources in East Asia: Lessons from East Asia", The World Bank, 1999, ISBN 978-0-821345-08-5 == External links == Speleogenesis Network, a communication platform for physical speleology and karst science research Speleogenesis and Karst Aquifers – a large glossary of Karst related terms Acta Carsologica – research papers and reviews in all the fields related to karst CDK Citizens of the Karst – Citizens of the Karst, a non profit NGO dedicated to the protection of the Puerto Rican Karst (English site available) The Virtual Cave's page on karst landforms Karst Information Portal - an open-access digital library linking scientists, managers, and explorers

Landforms

Salt cave

A salt cave is a cave formed within rock salt by dissolution of this very soluble rock by water. As with other soluble rocks, a distinctive set of landscape features can arise from the solutional process; in this case it is known as salt karst or 'halite karst'. The three key areas of salt karst are those in Iran, Israel and Spain, together with an example in Romania. Malcham cave in Israel is the longest salt cave in the world with a measured length of over 10km. It is located at Mount Sodom. There are significant salt caves on Qeshm Island in Iran including Tri Nahacu Cave and Namakdan Cave. This cave was listed in October 2022 by the International Union of Geological Sciences in their 'First 100 IUGS Geological Heritage Sites' as being of global significance for the understanding of tectonics and ongoing geological processes. Amongst the caves developed within the several salt karsts in Spain are Cova dels Meandres de Sales which at 4.3km in length is the world's third longest. The fourth longest is Pestera 6S de la Mânzălesti, in România, at 3.1km in length. == References ==

Landforms

Koog

A koog (plural: köge) or groden is a type of polder found on the North Sea coast of Germany that is established by the construction of dykes enclosing the land which is then drained to form marshland. This type of land reclamation is also used along rivers. In general, a koog is protected by embankments known as dykes (Deiche). == Etymology == Unlike the meaning in modern German, Ingvaeonic *kāg, Old Dutch *kōg, modern Dutch koog and West Frisian Dutch kaag all designate "land outside the dike". In the Netherlands, it primarily survives in place names (e.g. De Koog, Koog aan de Zaan, Kaag). From the Dithmarschen word koch (15th and 16th centuries), it went into Danish as kog. In North Frisian it is kuch. The spelling koog was used by the poet Michael Richey in 1755 and around 1700, what is now the port of Cuxhaven was still called Koogshaven. == Polders == In the Netherlands and in the adjacent regions of East Frisia the word polder (Low German: Poller) is used for land enclosed by embankments from where the water is artificially drained. The etymology of the word polder/poller is unclear but it is probably related to English pool. == Groden == The term groden (c.f. the English verb "to grow") used in Lower Saxony, particularly in the eastern part of East Frisia and in the Oldenburg Land, refers to new areas of land washed up by the sea. Sediments are deposited by the sea on mud flats when the tides change. After reaching a certain height, the land is dyked. Dyked land becomes innengroden. As a result of draining the fertile soil compacts and, over time, can sink until it is below sea level. The rising sea level in front of the dyke and the sinking of the old, now drained, sea areas behind the dyke leads to further dykes being built at an ever-higher level to enclose the newly dyked areas of marsh. In this way a so-called "polder staircase" is formed.The name groden is found for example in the borough of Wilhelmshaven in the villages of Altengroden, Neuengroden and Fedderwardergroden, the Heppenser, Voslapper and Rüstersieler Groden, and in the surrounding area are the Cäciliengroden, Petersgroden and Adelheidsgroden. All these areas, whether they emerged more recently (i.e. in the 20th century) or in older times, were formed as a result of dyke enclosure and Aufspülung, as is often the case with polders. → See also salt marsh == Drainage == Because a koog often lies below the level of the adjacent sea or river, it has to be continually drained. This is carried out with the aid of soakaways, sluices, pumping stations and water pumps.Today the pumps are powered by engines, in pre-industrial times and sometimes even into the period of intense industrialisation, they were driven by wind power (wind pumps). The groups of wind mills on the dykes of the Rhine delta - a symbol of the Netherlands - are old water pumps. == Riparian köge == As well land reclaimed from the sea, a koog may also refer to land reclaimed alongside rivers. These are usually wet areas that are now used for agriculture. This entails creating a completely new ecosystem from a river meadow or a carr. Often its name will recall its original situation, for example, the Oderbruch. On the Rhine, Elbe and Oder rivers these areas are also used for flood protection. Once the flooding has subsided, water is pumped out again and the land can be used for farming until the next flood. Until the 1950s, köge were mainly created to reclaim land for farming; since then coastal defence has been the main aim. == North German köge == On the western coast of Schleswig-Holstein and on the shores of the Lower Elbe over 230 koogs have been created over the centuries. The oldest ones are in the borough of Eiderstedt; they date to the 11th century. After the Burchardi flood of 1634, an increasing number of "octroi" koogs were built. Well known koogs include: County of Dithmarschen Christianskoog Delver Koog Dieksanderkoog (formerly Adolf Hitler Koog) Friedrichsgabekoog Friedrichskoog Hedwigenkoog Kaiser-Wilhelm-Koog Karolinenkoog Kronprinzenkoog Neufelderkoog Preiler Koog Speicherkoog in the Bay of Meldorf Wesselburenerkoog Westerkoog County of Nordfriesland Augustenkoog Beltringharder Koog Hauke-Haien-Koog (named after the lead character of the novella The Rider on the White Horse by Theodor Storm) Friedrich-Wilhelm-Lübke-Koog – in 1954 the last koog reclaimed for settlement in Schleswig-Holstein. Gotteskoog Tümlauer-Koog (formerly Hermann Göring Koog) Norderheverkoog (formerly Horst Wessel Koog) Bottschlotter Koog (Dagebüll) Kleiseerkoog (Galmsbüll) Herrenkoog Former island of Nordstrand Elisabeth-Sophien-Koog Alter Koog Osterkoog Trendermarschkoog Neukoog Morsumkoog Pohnshalligkoog Municipality of Reußenköge Cecilienkoog Desmerciereskoog Louisen-Reußen-Koog Reußenkoog Sönke-Nissen-Koog Sophien-Magdalenen-Koog County of Pinneberg Hetlinger Neuerkoog == Literature == Harry Kunz, Albert Panten: Die Köge Nordfrieslands. Mit Karte. Nordfriisk Instituut, Bräist/Bredstedt, 1997, ISBN 3-88007-251-5 (Nordfriisk Instituut 144). == External links == Salzderhelden == References ==

Landforms

Kuppe

A Kuppe is the term used in German-speaking central Europe for a mountain or hill with a rounded summit that has no rock formation, such as a tor, on it. A range of such hills is called a Kuppengebirge. In geology the term also refers to corresponding stratigraphic forms. The term is similar to the English topographical and geological terms, knoll and dome. It is also analogous to the French word ballon which means a mountain with a rounded summit. In cartography in German-speaking countries, the term is used more widely to refer to all eminences (biaxially convex landforms) i.e. including those with a more pointed appearance. Kuppen are a common feature of many ranges within the German Central Uplands including the Rhön Mountains. == Derivation == Kuppe comes from the Middle High German language of the 18th century, probably deriving from the Late Latin/Common Roman word cuppa = "beaker", which then became commonly used in the sense of Haube ("helmet" or "covering") for a summit. == Geomorphology and geology == Kuppengebirge ("kuppe hills") is a geomorphological term. Their formation usually arises as a combination of certain types of rock and the onset of steady erosion processes. == Distribution == Kuppen are typical of the Central Uplands and the Prealps of Europe. For example, the many domed summits of the Fichtel Mountains or the Pohorje are called kuppen, but they also occur in hilly areas. In this connexion, for example, a part of the Rhön Mountains is known as the Kuppen Rhön (Kuppenrhön) and Kuppe or Koppe is often part of the name of mountains and hills, e.g. the Wasserkuppe and the Schneekoppe. Places where sedimentary beds have bulged and where rising oil or natural gas has accumulated, are also called kuppen. == References ==

Landforms

Land bridge

In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea levels fall, exposing shallow, previously submerged sections of continental shelf; or when new land is created by plate tectonics; or occasionally when the sea floor rises due to post-glacial rebound after an ice age. == Prominent examples == Adam's Bridge (also known as Rama Setu), connecting India and Sri Lanka The Bassian Plain, which linked Australia and Tasmania The Bering Land Bridge (aka Beringia), which intermittently connected Alaska (Northern America) with Siberia (North Asia) as sea levels rose and fell under the effect of ice ages Land bridges of Japan, several land bridges which connected Japan to Russia and Korea at various times in history. De Geer Land Bridge, a route that connected Fennoscandia to northern Greenland Doggerland, a former landmass in the southern North Sea which connected the island of Great Britain to continental Europe during the last ice age The Isthmus of Panama, whose appearance three million years ago allowed the Great American Biotic Interchange between North America and South America The Thule Land Bridge, a since disappeared land bridge between the British Isles and Greenland The Sinai Peninsula, linking Africa and Eurasia Torres Strait land bridge, Sahul, between modern-day West Papua and Cape York == Land bridge theory == In the 19th century, scientists including Joseph Dalton Hooker noted puzzling geological, botanical, and zoological similarities between widely separated areas. To solve these problems, they proposed land bridges between appropriate land masses. In geology, the concept was first proposed by Jules Marcou in Lettres sur les roches du Jura et leur distribution géographique dans les deux hémisphères ("Letters on the rocks of the Jura [Mountains] and their geographic distribution in the two hemispheres"), 1857–1860.The hypothetical land bridges included: Archatlantis from the West Indies to North Africa Archhelenis from Brazil to South Africa Archiboreis in the North Atlantic Archigalenis from Central America through Hawaii to Northeast Asia Archinotis from South America to Antarctica Lemuria in the Indian OceanThe theory of continental drift provided an alternate explanation that did not require land bridges. However the continental drift theory was not widely accepted until the development of plate tectonics in the early 1960s, which more completely explained the motion of continents over geological time. == See also == Habitat fragmentation Sea level rise == References == == Further reading == Ernest Ingersoll (1920). "Land-Bridges Across the Oceans" . Encyclopedia Americana. == External links ==

Landforms

Ländchen (Havelland)

A Ländchen is the German name given to several Ice Age plateaux in the Havelland region, which climb to over 70 metres above the formerly marshy urstromtal levels (old glacial meltwater valleys) of the Havelland Luch and the Rhinluch. The difference between these Ländchen and the surrounding countryside is even more marked because of the different land uses to which they are put. Extensive pastures in the lowlands contrast with the arable fields and woods on the low hills. Geologically they are largely complete formations of ground moraine from the Saale and Weichselian glaciations that, in places, are covered by gently rolling end moraines. Their names are: Ländchen Bellin near Fehrbellin (52.78°N 12.79°E / 52.78; 12.79 (Ländchen Bellin)) Ländchen Friesack near Friesack (52.70°N 12.56°E / 52.70; 12.56 (Ländchen Friesack)) Ländchen Glien near Paaren im Glien north of Falkensee (52.68°N 13.05°E / 52.68; 13.05 (Ländchen Glien)) Ländchen Rhinow near Rhinow near the confluence of the Rhin and the Havel (52.72°N 12.35°E / 52.72; 12.35 (Ländchen Rhinow)) Land Schollene between Havel and the Elbe valley, west of Rathenow (52.63°N 12.16°E / 52.63; 12.16 (Land Schollene)) Ribbeck Heath, part of the Nauen Plateau (52.60°N 12.73°E / 52.60; 12.73 (Ribbeck Heath)) Zootzen north of Friesack, scarcely higher than the Luche (52.76°N 12.67°E / 52.76; 12.67 (Zootzen)) == Sources == Topographic map, 1:100,000 series, Sheets C 3538 Brandenburg an der Havel and C 3542 Berlin West, both from LGB Brandenburg

Landforms

Landmass

A landmass, or land mass, is a large region or area of land that is in one piece and not broken up by oceans. The term is often used to refer to lands surrounded by an ocean or sea, such as a continent or a large island. In the field of geology, a landmass is a defined section of continental crust extending above sea level.Continents are often thought of as distinct landmasses and may include any islands that are part of the associated continental shelf. When multiple continents form a single contiguous land connection, the connected continents may be viewed as a single landmass. Earth's largest landmasses are (starting with largest): Afro-Eurasia (main landmass of the geoscheme region of the same name and its continental parts Africa and Eurasia - or Europe and Asia; the center of Earth's land hemisphere, comprising more than half of Earth's landmass) Americas (main landmass of the geo-region of the same name and its continental parts North and South America; comprising most of the landmass of the Western Hemisphere) Antarctica (main landmass of the geo-region and continent of the same name) Mainland Australia (main landmass of the geo-region Oceania, its sub-region Australasia, the continent Australia and the country Australia) == See also == Coastline paradox Continent Boundaries between the continents of Earth Island List of islands by area Landform Glossary of landforms Mainland Supercontinent == References ==

Landforms

Little Switzerland (landscape)

A little Switzerland or Schweiz is a landscape, often of wooded hills. This Romantic aesthetic term is not a geographic category, but was widely used in the 19th century to connote dramatic natural scenic features that would be of interest to tourists. Since it was ambiguous from the very beginning, it was flexibly used in travel writing to imply that a landscape had some features, though on a much smaller scale, that might remind a visitor of Switzerland. == Rock outcrops == The original generic term was applied to dozens of locations in Europe, the bulk of them German-speaking, as well as to other parts of the world, to direct attention to rock outcrops that stand out, usually amid steep forest. The original, 18th-century comparison was usually with the fissured crags of the Jura Mountains on the Franco-Swiss border which hardly rise higher than 1700 metres. Histories of Saxon Switzerland (Sächsische Schweiz) in Saxony, Germany, assert that the landscape description schweiz arose there at the end of the 18th century. Schweiz is the German-language name of Switzerland. The term was used both alone and with the prefix "little", for example in the title of an 1820 German book-length poem, Die kleine Schweiz by Jakob Reiselsberger, which praised the rocky scenery of a part of Franconia in Germany known thereafter as the Franconian Switzerland (Fränkische Schweiz). The term was already colloquial by this time in English: in 1823 a correspondent asserted in The Gentleman's Magazine that a steep area by the road outside Petersfield in southern England was a little Switzerland. The aesthetic term, to describe picturesque exposed rock and steepness rather than altitude, was also in common use in other European languages, including the French term Suisse. Rocks and wild landscapes were a favoured theme in Romantic painting. The many English places praised in 19th-century promotional literature as "little Switzerland" include Church Stretton, Whitfield and the coastal area around the North Devon twin towns of Lynton and Lynmouth. Chalet-style buildings were sometimes erected to emphasize little Switzerland pretensions, for example at Matlock Bath, which (unusually for England) also features a cable car. == Mountains == From the beginning, the term was often understood as a comparison to the snow-capped Alps rather than to the Jura. The following passage, describing Wales, appears in an 1831 English-language edition of Malte-Brun's Universal Geography, which had originally been written in French in 1803–07: The great number of mountains which diversify its surface have gained it the name of Little Switzerland. It will be readily understood that it is not in the loftiness of their summits this resemblance can be traced with the country of the Alps, but in their steep, rough and perpendicular sides, the depth of their narrow valleys, the small but limpid lakes which occur at every step, the great number of rivers and streams which are now precipitated in cascades, and now roll their waters slowly through the meadows, the damp fogs which rise from the surface of these waters and often hang about the summits of the highest mountains, and the snow which frequently continues upon the heights till the end of spring: all of which give to these mountains, notwithstanding their inconsiderable height ... an appearance resembling those lordly eminences mounting up to the clouds and bearing on their heads eternal snows. Describing the Atlantic island of St Helena in A New Voyage Round the World (1823–26), Otto von Kotzebue and Johann Friedrich Eschscholtz were translated into English as writing: The environs of Sandy Bay would be a perfect little Switzerland, but that the glaciers are wanting to complete the resemblance. Scattered among the enormous masses of rock which lie confusedly heaped upon each other a frightful wilderness and most smilingly picturesque landscape alternately present their contrasted images. In the United States, the raw White Mountains of New Hampshire, which were soon to be one of the definitive subjects of American Romantic painting, were termed a little Switzerland by travel writer Henry Tudor as early as 1832. == Lakelands == In the later 19th century, authors and tourism promoters would praise picture-postcard summer scenery of woods and low hills reflected in blue lakes as a little Switzerland or schweiz. Whereas the earlier use had implied a landscape of dangers, this was a term for beauty. This usage, reflected today in the official geographical terms for the Holstein Switzerland (Holsteinische Schweiz) and Mecklenburg Switzerland (Mecklenburgische Schweiz) in Germany, where there are neither mountains nor outcrops, is difficult to account for, but may refer to prestigious Swiss lakeside tourist destinations such as Zurich, Lucerne or Interlaken or to Lakes Geneva and Constance. == Official names == The term has often appeared anachronistic since travel to Switzerland became affordable. By the 21st century, it was common for observers to express puzzlement that the "little Switzerland" label applied at all to regions such as the Suisse Normande, or to the Holstein Switzerland where the flat hilltops are no more than 150 metres above the lake surfaces. In 1992, the Swiss Tourism Federation counted more than 190 places round the world that had at least for some period been named after Switzerland, either because of a fancied scenic resemblance, in jest or referring to a banking haven, political neutrality or habitation by Swiss emigrants. No fewer than 67 places in neighbouring Germany were said by the Federation to have adopted little Switzerland names. While the byname has fallen out of fashion in some places, it persists as the official geographical name for several administrative regions and national parks including (with dates of legal designation): Bohemian Switzerland (České Švýcarsko, nature park, Czech Republic, legislation with effect 2000) Bremen Switzerland (undulating geest north of Bremen, that reaches 30 m; c.f. the flat land on which Bremen is built.) Franconian Switzerland (tourism region, Germany, designated 1968) Hersbruck Switzerland (Hersbrucker Schweiz), low mountain region around Hersbruck, Germany Hohburg Switzerland (Hohburger Schweiz), alternative name for the Hohburg Hills near Leipzig Holstein Switzerland (nature park, Germany, formed by association 1986) Kashubian Switzerland (Szwajcaria Kaszubska, Poland) Kroppach Switzerland, rocky upland region near Kroppach in the Westerwald Marcher Switzerland (Märkische Schweiz, nature park, Germany, by decree 1990) Mecklenburg Switzerland (nature park, Germany, designated 1997) Rhenish-Hessian Switzerland (protected landscape and recreation area in Rhineland-Palatinate). Rostock Switzerland (rugged terminal moraine landscape near the Baltic coast in Mecklenburg-Vorpommern). Rüdigsdorf Switzerland (hill range and karst landscape in the southern Harz, most of which is a nature reserve) Ruppin Switzerland (a forested lakeland in Brandenburg) Saxon Switzerland (nature park, Germany, designated 1990; local government area, now in Saxon Switzerland-East Ore Mountains district)Business promotion regions using the name without legally defined boundaries include: Suisse Normande (in the border region of the departments Calvados and Orne, France) Little Switzerland (Luxembourg) (dolomite formations near Echternach, Luxembourg)Notable privately developed properties known by the name include: Little Switzerland, North Carolina (resort development on hilltop in North Carolina, US, from 1909) Little Switzerland (Wisconsin) (a ski resort from 1941 onwards)In Israel, there is an area in Mount Carmel National Park popularly referred to as Little Switzerland (שוויצריה הקטנה). This name has been adopted by the Israel Nature and Parks Authority, which explains the name as having been given “due to the evergreen forest, the spectacular wild landscapes, and the pleasant weather on most days of the year.” == Usage == In English, "Little Switzerland" is usually said without any definite article or additional adjective, but often with a genitive modifier if there are several little Switzerlands within one nation, e.g. North Carolina's Little Switzerland. In European languages where Switzerland proper takes a definite article, little Switzerlands do likewise. Their English names may echo the vernacular, being capitalized and modified to the English alphabet, sometimes taking an English definite article, e.g. the Saechsische Schweiz (die Sächsische Schweiz) and the Suisse Normande (la Suisse normande). English forms are also widespread, e.g. Holstein Switzerland (Dickinson, 1964), Swiss Franconia (Michelin, 1993), Franconian Switzerland (Fodor, 1962, and Bolt, 2005.) == See also == Geography of Switzerland == References ==

Landforms

Lynchet

A lynchet or linchet is an earth terrace found on the side of a hill. Lynchets are a feature of ancient field systems of the British Isles. They are commonly found in vertical rows and more commonly referred to as "strip lynchets". Lynchets appear predominantly in Southern Britain and many are in areas close to Iron Age forts and other earthworks, including later Roman earthworks and earlier barrows from the Neolithic and Bronze Age periods. The size, location, spacing and number of rows of many strip lynchets indicates that many were man-made. It is most likely that lynchets were dug to maximise the use of land for agriculture, although they may have had other, ceremonial uses. The word is the diminutive form of lynch, now rarely appearing in the English language, indicating an agricultural terrace; it is cognate with the golf links. However, both "lynchet" and "lynch" may also be used to refer to a strip of green land left between two pieces of ploughed land on non-sloping ground; or to a natural slope or terrace along the face of a chalk down.The traditional theory on the formation of lynchets is that they may form naturally on the downslope of a field ploughed over a long period of time. The disturbed soil slips down the hillside to create a "positive lynchet" (where the new surface is higher than the original surface), while the area reduced in level becomes a "negative lynchet" (where the new surface is lower). In Loders, Dorset, lynchets form a terraced band structure similar to an amphitheatre overlooking the village. Lynchets also form part of the conservation area of the neighbouring village of Uploders, where they apparently form old hillside field systems in close proximity to an Iron Age fort and hill-top barrows. 19th-century maps indicate that cider orchards were planted on some lynchets in that area. == See also == Ridge and furrow Céide Fields Lazy bed Cord rig == References == == Further reading == Johnson, Walter (1908). Folk-Memory: or the continuity of British archaeology. Oxford: Clarendon Press. pp. 263–294.

Landforms

Mallín

Mallín is a type of meadow and wetland found in southern Chile and Argentina. Mallines are distinguished from other wetlands in that the groundwater level reaches the surface at them, yet the mallín is still an area of net infiltration. Soils in mallines are rich in organic matter. In Argentina mallins have been important grazing lands for cattle, sheep and horses. In eastern Patagonia the base of basaltic plateaus are associated with mallines. == See also == Ñadi == References ==

Landforms

Massif

A massif ( or ) is simply a principal mountain mass, for example, a compact portion of a mountain range, containing one or more summits (See for example, France's Massif Central.). In mountaineering literature, a massif is frequently used to denote the main mass of an individual mountain. As a purely scientific term in geology, however, a "massif" is separately and more specifically defined as a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. A massif is a smaller structural unit than a tectonic plate, and is considered the fourth-largest driving force in geomorphology.The word "massif" is taken from French (in which the word also means "massive"), where it is used to refer to a large mountain mass or compact group of connected mountains forming an independent portion of a range. The Face on Mars is an example of an extraterrestrial massif. Massifs may also form underwater, as with the Atlantis Massif. == List of massifs == === Africa === Adrar des Ifoghas – Mali Aïr Massif – Niger Benna Massif – Guinea Bongo Massif – Central African Republic Ennedi Plateau – Chad Kilimanjaro Massif – border of Kenya and Tanzania Oban Massif – Nigeria Marojejy Massif – Madagascar Mulanje Massif – Malawi Virunga Massif – border shared by Uganda, Rwanda and DR Congo Waterberg Biosphere – South Africa ==== Algeria ==== Collo Massif Edough Massif Khachna Massif === Antarctica === Borg Massif Craddock Massif Cumpston Massif Vinson Massif Otway Massif === Asia === Annapurna – Nepal Bromo-Tengger-Semeru – Indonesia Chu Pong Massif – Vietnam Dhaulagiri – Nepal Gasherbrum – China-Pakistan Kangchenjunga – Nepal–India Knuckles Massif – Sri Lanka Kondyor Massif – Russia Kugitangtau Ridge – Turkmenistan Kumgangsan – North Korea Logar ultrabasite massif – Afghanistan Mount Ararat – Turkey Mount Everest massif (including Lhotse) – border of Nepal and Tibet (China) Mount Kinabalu – Malaysia Mount Tomuraushi – Japan Nanga Parbat – Pakistan ==== India ==== Bundelkhand Nun Kun Panchchuli Shillong ==== Iran ==== Dena Hazaran Kheru-Naru (Chekel) Kholeno Mount Damavand Sabalan Takht-e Suleyman Massif Zard-Kuh ==== Kazakhstan ==== Degelen Kokshetau Massif Mount Ku Myrzhyk Semizbughy === Europe === Aarmassif – Switzerland Ardennes Massif – France/Belgium/Luxembourg Åreskutan – Sweden Arlberg – Austria Bohemian Massif – Czech Republic Ceahlău Massif – Romania Gotthard Massif – Switzerland Hesperian Massif – Iberian Peninsula Jungfrau Massif – Switzerland Mangerton Mountain – Ireland Montgris – Spain Montserrat – Spain Mont Blanc massif – Italy/France/Switzerland Rhenish Massif – Germany, Belgium, Luxembourg and France Rila – Rhodope Massif – Bulgaria/Greece Troodos – Cyprus Untersberg – Germany/Austria Vitosha Massif – Bulgaria ==== France ==== Alpilles Aravis Range Armorican Massif Bauges Massif Beaufortain Massif Belledonne massif Bornes Massif Calanques Massif Cerces Massif Chablais Massif Chartreuse Massif Dévoluy Massif Massif des Écrins Jura Mountains Lauzière massif Luberon Massif Central Massif de l'Esterel Mercantour Monte Cinto massif Taillefer Massif Queyras Massif Vanoise Massif Vercors Plateau Vosges Mountains ==== Italy ==== Gran Sasso d'Italia Grappa Massif Massiccio del Matese Massiccio del Pollino Monte Ermada Sila Massif Speikboden (South Tyrol) ==== United Kingdom ==== Ben Nevis massif Cornubian Massif Long Mynd Snowdon Massif === North America === ==== Canada ==== Laurentian Massif – Quebec Le Massif de Charlevoix – Quebec Mount Logan – YukonBritish Columbia Mount Cayley – British Columbia Level Mountain Mount Edziza Mount Meager massif Mount Septimus ==== United States ==== Adirondack Massif – New York Denali – Alaska Mount Juneau – Alaska Mount Katahdin – Maine Mount Le Conte – Tennessee Mount Shuksan – Washington Mount Timpanogos – Utah Shenandoah – Virginia French Broad – North Carolina and Virginia Teton Range – Wyoming === Oceania === Big Ben – Heard Island Ahipara Gumfields – New Zealand === Caribbean === Massif de la Hotte – Haiti Valle Nuevo Massif – Dominican Republic === South America === Brasilia Massif – Brazil, Argentina, Paraguay, Uruguay. Neblina Massif – Venezuela–Brazil border Colombian Massif – Colombia North Patagonian Massif – Argentina Deseado Massif – Argentina === Submerged === Atlantis Massif – part of the Mid-Atlantic Ridge in the North Atlantic Ocean Tamu Massif — the largest volcano on Earth == References ==

Landforms

Moorland

Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland, nowadays, generally means uncultivated hill land (such as Dartmoor in South West England), but also includes low-lying wetlands (such as Sedgemoor, also South West England). It is closely related to heath, although experts disagree on what precisely distinguishes these types of vegetation. Generally, moor refers to highland and high rainfall zones, whereas heath refers to lowland zones which are more likely to be the result of human activity. Moorland habitats mostly occur in tropical Africa, northern and western Europe, and neotropical South America. Most of the world's moorlands are diverse ecosystems. In the extensive moorlands of the tropics, biodiversity can be extremely high. Moorland also bears a relationship to tundra (where the subsoil is permafrost or permanently frozen soil), appearing as the tundra and the natural tree zone. The boundary between tundra and moorland constantly shifts with climatic change. == Heather moorland == Heathland and moorland are the most extensive areas of semi-natural vegetation in the British Isles. The eastern British moorlands are similar to heaths but are differentiated by having a covering of peat. On western moors, the peat layer may be several metres thick. Scottish "muirs" are generally heather moors, but also have extensive covering of grass, cotton-grass, mosses, bracken and under-shrubs such as crowberry, with the wetter moorland having sphagnum moss merging into bog-land.There is uncertainty about how many moors were created by human activity. Oliver Rackham writes that pollen analysis shows that some moorland, such as in the islands and extreme north of Scotland, are clearly natural, never having had trees, whereas much of the Pennine moorland area was forested in Mesolithic times. How much the deforestation was caused by climatic changes and how much by human activity is uncertain. == Ecology == A variety of distinct habitat types are found in different world regions of moorland. The wildlife and vegetation forms often lead to high endemism because of the severe soil and microclimate characteristics. An example of this is the Exmoor Pony, a rare horse breed which has adapted to the harsh conditions in England's Exmoor. In Europe, the associated fauna consists of bird species such as red grouse, hen harrier, merlin, golden plover, curlew, skylark, meadow pipit, whinchat, ring ouzel, and twite. Other species dominate in moorlands elsewhere. Reptiles are few due to the cooler conditions. In Europe, only the common viper is frequent, though in other regions moorlands are commonly home to dozens of reptile species. Amphibians such as frogs are well represented in moorlands. When moorland is overgrazed, woody vegetation is often lost, being replaced by coarse, unpalatable grasses and bracken, with a greatly reduced fauna. Some hill sheep breeds, such as Scottish Blackface and the Lonk, thrive on the austere conditions of heather moors. == Management == Burning of moorland has been practised for a number of reasons, for example, when grazing is insufficient to control growth. This is recorded in Britain in the fourteenth century. Uncontrolled burning frequently caused (and causes) problems and was forbidden by statute in 1609. With the rise of sheep and grouse management in the nineteenth century, it again became common practice. Heather is burnt at about 10 or 12 years old when it will regenerate easily. Left longer, the woodier stems will burn more aggressively and will hinder regrowth. Burning of moorland vegetation needs to be very carefully controlled, as the peat itself can catch fire, and this can be difficult if not impossible to extinguish. In addition, uncontrolled burning of heather can promote alternative bracken and rough grass growth, which ultimately produces poorer grazing. As a result, burning is now a controversial practice; Rackham calls it "second-best land management".Mechanical cutting of the heather has been used in Europe, but it is important for the material to be removed to avoid smothering regrowth. If heather and other vegetation are left for too long, a large volume of dry and combustible material builds up. This may result in a wildfire burning out a large area, although it has been found that heather seeds germinate better if subject to the brief heat of controlled burning.In terms of managing moorlands for wildlife, in the UK, vegetation characteristics are important for passerine abundance, whilst predator control benefits red grouse, golden plover, and curlew abundances. To benefit multiple species, many management options are required. However, management needs to be carried out in locations that are also suitable for species in terms of physical characteristics such as topography, climate and soil. == Moorland in literature == The development of a sensitivity to nature and one's physical surroundings grew with the rise of interest in landscape painting, and particularly the works of artists that favoured wide and deep prospects, and rugged scenery. To the English Romantic imagination, moorlands fitted this image perfectly, enhancing the emotional impact of the story by placing it within a heightened and evocative landscape. Moorland forms the setting of various works of late Romantic English literature, ranging from the Yorkshire moorland in Emily Brontë's Wuthering Heights and The Secret Garden by Frances Hodgson Burnett to Dartmoor in Arthur Conan Doyle's Holmesian mystery The Hound of the Baskervilles. They are also featured in Charlotte Bronte's Jane Eyre representing the heroine's desolation and loneliness after leaving Mr Rochester. Enid Blyton's Famous Five series featured the young protagonists adventuring across various moorlands where they confronted criminals or other individuals of interest. Such a setting enhanced the plot as the drama unfolded away from the functioning world where the children could solve their own problems and face greater danger. Moorland in the Forest of Bowland in Lancashire is the setting for Walter Bennett's The Pendle Witches, the true story of some of England's most infamous witch trials. In Erin Hunter's Warriors series, one of the four Clans, WindClan, lives in the moorland alone. Michael Jecks, author of Knights Templar Mysteries, sets his books in and around Dartmoor, England. Paul Kingsnorth’s Beast is also set on a western English moor, using the barren landscape and fields of heather to communicate themes of timelessness and distance from civilization. == Notable moorlands == === Africa === ==== Democratic Republic of the Congo ==== Ruwenzori-Virunga montane moorlands ==== Ethiopia ==== Ethiopian montane moorlands ==== Kenya ==== East African montane moorlands Mount Kenya ==== Rwanda ==== Ruwenzori-Virunga montane moorlands ==== Sudan ==== East African montane moorlands Ethiopian montane moorlands ==== Tanzania ==== East African montane moorlands Kilimanjaro Mount Meru ==== Uganda ==== East African montane moorlands === Europe === ==== Austria ==== Tanner Moor Längsee Moor Moorbad Gmös ==== Belgium ==== Weißer Stein (Eifel) High Fens ==== France ==== Monts d'Arrée ==== Germany ==== Großes Torfmoor Hücker Moor Oppenwehe Moor Worringer Bruch High Fens ==== The Netherlands ==== Dwingelderveld Bargerveen Fochteloërveen The Peel ==== Great Britain ==== Great Britain is home to an estimated 10–15% of the world's moors. Notable areas of upland moorland in Britain include the Lake District, the Pennines (including the Dark Peak and Forest of Bowland), Mid Wales, the Southern Uplands of Scotland, the Scottish Highlands, and a few pockets in the West Country. Bleaklow, Dark Peak Bodmin Moor, Cornwall Black Mountains, Wales Brecon Beacons, Wales Dartmoor, Devon Drumossie Moor, often called Culloden Moor, the site of the Battle of Culloden Exmoor, West Somerset & North Devon Forest of Bowland, Lancashire Hexhamshire Moors, Northumberland and County Durham North York Moors, North Yorkshire Migneint, Gwynedd Mynydd Hiraethog, Denbighshire and Conwy Penwith, Cornwall Rannoch Moor, Highlands, Scotland Rombalds Moor (including Ilkley Moor), West Yorkshire Rossendale Valley, Lancashire Saddleworth Moor, Greater Manchester Shropshire Hills, small pockets of moorland such as the Long Mynd West Pennine Moors, including Oswaldtwistle Moor, Haslingden Moor, Rivington Moor and Darwen Moor in Lancashire Yorkshire Dales National Park, North Yorkshire Ythan Estuary complex, Aberdeenshire, Scotland: largest coastal moorland in the British Isles, known for high biodiversity ==== Spain ==== Moorlands are called páramos in Spanish. They are particularly common in Northern Spain and the Meseta Central. Boedo, Palencia, Castile Páramo del Duratón, Castile Paramo de Masa, Burgos, Castile Páramo del Sil, Galicia Las Loras, Castile === South America === ==== Argentina ==== Magellanic moorland ==== Chile ==== Magellanic moorland ==== Colombia ==== Colombia is one of only three countries in the world to be home to páramo (tropical moorland) and more than 60% of the paramo regions are found on its soil. Sumapaz Páramo, Bogota Chingaza National Natural Park, Cundinamarca department Oceta Páramo, Boyacá Department Iguaque, Boyacá Department Puracé, Cauca Department Páramo de Santurbán, Santander Department == See also == Fen Siskiyou plateau and the high desert (Oregon) – two similar habitats, although more arid, found in western North America Páramo == References ==

Landforms

Mountain chain

A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains, or a contiguous ridge of mountains within a larger mountain range. The term is also used for elongated fold mountains with several parallel chains ("chain mountains"). While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of hills tends to be referred to a ridge or hill chain. Elongated mountain chains occur most frequently in the orogeny of fold mountains, (that are folded by lateral pressure), and nappe belts (where a sheetlike body of rock has been pushed over another rock mass). Other types of range such as horst ranges, fault block mountain or truncated uplands rarely form parallel mountain chains. However, if a truncated upland is eroded into a high table land, the incision of valleys can lead to the formations of mountain or hill chains. == Formation of parallel mountain chains == The chain-like arrangement of summits and the formation of long, jagged mountain crests – known in Spanish as sierras ("saws") – is a consequence of their collective formation by mountain building forces. The often linear structure is linked to the direction of these thrust forces and the resulting mountain folding which in turn relates to the fault lines in the upper part of the earth's crust, that run between the individual mountain chains. In these fault zones, the rock, which has sometimes been pulverised, is easily eroded, so that large river valleys are carved out. These, so called longitudinal valleys reinforce the trend, during the early mountain building phase, towards the formation of parallel chains of mountains. The tendency, especially of fold mountains (e. g. the Cordilleras) to produce roughly parallel chains is due to their rock structure and the propulsive forces of plate tectonics. The uplifted rock masses are either magmatic plutonic rocks, easily shaped because of their higher temperature, or sediments or metamorphic rocks, which have a less robust structure, that are deposited in the synclines. As a result of orogenic movements, strata of folded rock are formed that are crumpled out of their original horizontal plane and thrust against one another. The longitudinal stretching of the folds takes place at right angles to the direction of the lateral thrusting. The overthrust folds of a nappe belt (e.g. the Central Alps) are formed in a similar way. Although the fold mountains, chain mountains and nappe belts around the world were formed at different times in the earth's history, all during their initial mountain building phases, they are nevertheless morphologically similar. Harder rock forms continuous arêtes or ridges that follow the strike of the beds and folds. The mountain chains or ridges therefore run approximately parallel to one another. They are only interrupted by short, usually narrow, transverse valleys, which often form water gaps. During the course of earth history, erosion by water, ice and wind carried away the highest points of the mountain crests and carved out individual summits or summit chains. Between them, notches were formed that, depending on altitude and rock-type, form knife-edged cols or gentler mountain passes and saddles. == Dominant rocks and mountain forms == Nappe or fold mountains, with their roughly parallel mountain chains, generally have a common geological age, but may consist of various types of rock. For example, in the Central Alps, granitic rocks, gneisses and metamorphic slate are found, while to the north and south, are the Limestone Alps. The Northern Limestone Alps are, in turn, followed by soft flysch mountains and the molasse zone. The type of rock influences the appearance of the mountain ranges very markedly, because erosion leads to very different topography depending on the hardness of the rock and its petrological structure. In addition to height and climate, other factors are the layering of the rock, its gradient and aspect, the types of waterbody and the lines of dislocation. For hard rock massifs, rugged rock faces (e.g. in the Dolomites) and mighty scree slopes are typical. By contrast, flysch or slate forms gentler mountain shapes and kuppen or domed mountaintops, because the rock is not porous, but easily shaped. == See also == Orogeny Tectonics List of highest mountains on Earth List of mountain ranges == References == == Literature == Wissen heute: Geologie. Kaiser-Verlag, Florence/Klagenfurt, 1995 Der geologische Aufbau Österreichs. Geologische Bundesanstalt, Springer-Verlag Vienna/ New York PanGeo, Erdwissenschaften in Österreich. Conference proceedings, 200 pp., Sessions on the Neogene, TRANSALP I and II. Univ. Salzburg, 2005 Fischer-Lexikon Geographie, pp. 101–129, Frankfurt, 1959 Großer Weltatlas, Enzyklopädischer Teil (mountain building, folds and faults, the rock cycle). Publ. ÖAMTC, Vienna, ~1980 André Cailleux: Der unbekannte Planet: Anatomie der Erde. Kindlers Universitätsbibliothek, Munich, 1968, Chapters 1 and 3 Gebirge, in: Lueger, Otto: Lexikon der gesamten Technik und ihrer Hilfswissenschaften, Vol. 4 Stuttgart, Leipzig, 1906, pp. 316-317.

Landforms

Mud volcano

A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots. The mud produced by mud volcanoes is mostly formed as hot water, which has been heated deep below the Earth's surface, begins to mix and blend with subterranean mineral deposits, thus creating the mud slurry exudate. This material is then forced upwards through a geological fault or fissure due to local subterranean pressure imbalances. Mud volcanoes are associated with subduction zones and about 1100 have been identified on or near land. The temperature of any given active mud volcano generally remains fairly steady and is much lower than the typical temperatures found in igneous volcanoes. Mud volcano temperatures can range from near 100 °C (212 °F) to occasionally 2 °C (36 °F), some being used as popular "mud baths".About 86% of the gas released from these structures is methane, with much less carbon dioxide and nitrogen emitted. Ejected materials are most often a slurry of fine solids suspended in water that may contain a mixture of salts, acids and various hydrocarbons.Possible mud volcanoes have been identified on Mars. == Details == A mud volcano may be the result of a piercement structure created by a pressurized mud diapir that breaches the Earth's surface or ocean bottom. Their temperatures may be as low as the freezing point of the ejected materials, particularly when venting is associated with the creation of hydrocarbon clathrate hydrate deposits. Mud volcanoes are often associated with petroleum deposits and tectonic subduction zones and orogenic belts; hydrocarbon gases are often erupted. They are also often associated with lava volcanoes; in the case of such close proximity, mud volcanoes emit incombustible gases including helium, whereas lone mud volcanoes are more likely to emit methane. Approximately 1,100 mud volcanoes have been identified on land and in shallow water. It has been estimated that well over 10,000 may exist on continental slopes and abyssal plains. === Features === Gryphon: steep-sided cone shorter than 3 meters that extrudes mud Mud cone: high cone shorter than 10 meters that extrudes mud and rock fragments Scoria cone: cone formed by heating of mud deposits during fires Salse: water-dominated pools with gas seeps Spring: water-dominated outlets smaller than 0.5 metres Mud shield === Emissions === Most liquid and solid material is released during eruptions, but seeps occur during dormant periods. The mud is rich in halite (rock salt).First-order estimates of mud volcano emissions have been made (1 Tg = 1 million metric tonnes). 2002: L. I. Dimitrov estimated that 10.2–12.6 Tg/yr of methane is released from onshore and shallow offshore mud volcanoes. 2002: Etiope and Klusman estimated at least 1–2 and as much as 10–20 Tg/yr of methane may be emitted from onshore mud volcanoes. 2003: Etiope, in an estimate based on 120 mud volcanoes: "The emission results to be conservatively between 5 and 9 Tg/yr, that is 3–6% of the natural methane sources officially considered in the atmospheric methane budget. The total geologic source, including MVs (this work), seepage from seafloor (Kvenvolden et al., 2001), microseepage in hydrocarbon-prone areas and geothermal sources (Etiope and Klusman, 2002), would amount to 35–45 Tg/yr." 2003: analysis by Milkov et al. suggests that the global gas flux may be as high as 33 Tg/yr (15.9 Tg/yr during quiescent periods plus 17.1 Tg/yr during eruptions). Six teragrams per year of greenhouse gases are from onshore and shallow offshore mud volcanoes. Deep-water sources may emit 27 Tg/yr. Total may be 9% of fossil CH4 missing in the modern atmospheric CH4 budget, and 12% in the preindustrial budget. 2003: Alexei Milkov estimated approximately 30.5 Tg/yr of gases (mainly methane and CO2) may escape from mud volcanoes to the atmosphere and the ocean. 2003: Achim J. Kopf estimated 1.97×1011 to 1.23×1014 m³ of methane is released by all mud volcanoes per year, of which 4.66×107 to 3.28×1011 m³ is from surface volcanoes. That converts to 141–88,000 Tg/yr from all mud volcanoes, of which 0.033–235 Tg is from surface volcanoes. == Locations == === Europe === Dozens of mud volcanoes are located on the Taman Peninsula of Russia and the Kerch Peninsula of Crimea, Ukraine along with the south-western portion of Bulgaria near Rupite. In Italy, they are located in Emilia-Romagna (Salse di Nirano and Salse di Regnano), in the northern front of the Apennines as well as the southern part (Bolle della Malvizza), and in Sicily. On 24 August 2013, a mud volcano appeared in the center of the via Coccia di Morto roundabout in Fiumicino near Rome.Mud volcanoes are located in the Berca Mud Volcanoes near Berca in Buzău County, Romania, close to the Carpathian Mountains. They were declared a natural monument in 1924. === Asia === ==== Central Asia, The Caucasus, and The Caspian Sea ==== Many mud volcanoes exist on the shores of the Black Sea and Caspian Sea. Tectonic forces and large sedimentary deposits around the latter have created several fields of mud volcanoes, many of them emitting methane and other hydrocarbons. Features over 200 metres (656 ft) high occur in Azerbaijan, with large eruptions sometimes producing flames of similar scale. ==== Georgia ==== There are mud volcanoes in Georgia, such as the one at Akhtala. ==== Turkmenistan ==== Turkmenistan is home to numerous mud volcanoes, mainly in the Western part of the country including Cheleken Peninsula, which borders the Caspian Sea. ==== Iran and Pakistan (Makran Mountain Range) ==== Iran and Pakistan possess mud volcanoes in the Makran range of mountains in the south of the two countries. A large mud volcano is located in Balochistan, Pakistan. It is known as Baba Chandrakup (literally Father Moonwell) on the way to Hinglaj and is a Hindu pilgrim site. ==== Azerbaijan ==== Azerbaijan and its Caspian coastline are home to nearly 400 mud volcanoes, more than half the total throughout the continents. Most mud volcanoes in Azerbaijan are active; some are protected by the Azerbaijan Ministry of Ecology and Natural Resources, and the admission of people, for security reasons, is prohibited. In 2001, one mud volcano 15 kilometres (9 mi) from Baku made world headlines when it started ejecting flames 15 metres (49 ft) high.In Azerbaijan, eruptions are driven from a deep mud reservoir which is connected to the surface even during dormant periods, when seeping water shows a deep origin. Seeps have temperatures that are generally above ambient ground temperature by 2 °C (3.6 °F) – 3 °C (5.4 °F).On 4 July 2021, a mud volcano eruption on Dashli Island in the Caspian Sea, near an oil platform off the coast of Azerbaijan, caused a massive explosion and fireball, which was seen across the region, including from the capital Baku, which is 74 kilometres (46 mi) to the north. The flames towered 500 metres (1,640 ft) into the air. There were no reports of injuries or damage to any oil platforms. The last previous volcanic eruption on the island was recorded in 1945 and the preceding one in 1920. ==== India ==== Extensive mud volcanism on the Andaman accretionary prism, located at the Andaman Islands in the Indian Ocean. ==== Indonesia ==== Mud volcanism is a common phenomenon in Indonesia with dozens of structures present onshore and offshore.The Indonesian Lusi mud eruption is a hybrid mud volcano, driven by pressure from steam and gas from a nearby (igneous) volcanic system, and from natural gas. Geochemical, petrography and geophysical results reveal that it is a sediment-hosted hydrothermal system connected at depth with the neighboring Arjuno-Welirang volcanic complex.Drilling or an earthquake in the Porong subdistrict of East Java province, Indonesia, may have resulted in the Sidoarjo mud flow on 29 May 2006. The mud covered about 440 hectares, 1,087 acres (4.40 km2) (2.73 mi2), and inundated four villages, homes, roads, rice fields, and factories, displacing about 24,000 people and killing 14. The gas exploration company involved was operated by PT Lapindo Brantas and the earthquake that may have triggered the mud volcano was the 6.4 magnitude Yogyakarta earthquake of 27 May 2006. According to geologists who have been monitoring Lusi and the surrounding area, the system is beginning to show signs of catastrophic collapse. It was forecasted that the region could sag the vent and surrounding area by up to 150 metres (490 ft) in the next decade. In March 2008, the scientists observed drops of up to 3 metres (9.8 ft) in one night. Most of the subsidence in the area around the volcano is more gradual, at around 1 millimetre (0.039 in) per day. A study by a group of Indonesian geoscientists led by Bambang Istadi predicted the area affected by the mudflow over a ten-year period. More recent studies carried out in 2011 predict that the mud will flow for another 20 years, or even longer. Now named Lusi – a contraction of Lumpur Sidoarjo, where lumpur is the Indonesian word for "mud" – the eruption represent an active hybrid system. In the Suwoh depression in Lampung, dozens of mud cones and mud pots varying in temperature are found.In Grobogan, Bledug Kuwu mud volcano erupts at regular intervals, about every 2 or 3 minutes. ==== Iran ==== There are many mud volcanoes in Iran: in particular, in the provinces of Golestan, Hormozgan, and Sistan and Baluchestan, where Pirgel is located. ==== Mariana Forearc ==== There are 10 active mud volcanoes in the Izu–Bonin–Mariana Arc which can be found along a north to south trend, parallel to the Mariana trench. The material erupted at these mud volcanoes consists primarily of blue and green serpentinite mud which contains fresh and serpentinized peridotite material from the subduction channel. Fluid from the descending Pacific Plate is released by dehydration and alteration of rocks and sediment. This fluid interacts with mafic and ultramafic rocks in the descending Pacific Plate and overriding Philippine Plate, resulting in the formation of serpentinite mud. All of these mud volcanoes are associated with faults, indicating that the faults act as conduits for the serpentine mud to migrate from the subduction channel to the surface. These mud volcanoes are large features on the forearc, the largest of which has a diameter of ~50 kilometres (31 mi) and is over 2 kilometres (1.2 mi) high. ==== Pakistan ==== In Pakistan there are more than 130 active mud volcanoes or vents in Balochistan province; there are about 10 locations with clusters of mud volcanoes. In the west, in Gwadar District, the mud volcanoes are very small and mostly sit in the south of Jabal-e-Mehdi toward Sur Bandar. Many more are in the northeast of Ormara. The remainder are in Lasbela District and are scattered between south of Gorangatti on Koh Hinglaj to Koh Kuk in the North of Miani Hor in the Hangol Valley. In this region, the heights of mud volcanoes range between 300 and 2,600 feet (91.4 and 792.5 m). The most famous is Chandragup. The biggest crater is of V15 mud volcano found at 25°33'13.63"N. 65°44'09.66"E is about 450 feet (137.16 m) in diameter. Most mud volcanoes in this region are in out-of-reach areas having very difficult terrain. Mount Mehdi Mud Volcano near Miani Hor is also famous for large mud glacier around its caldera. Dormant mud volcanoes stand like columns of mud in many other areas. ==== Philippines ==== In the Turtle Islands, in the province of Tawi-Tawi, the southwestern edge of the Philippines bordering Malaysia, presence of mud volcanoes are evident on three of the islands – Lihiman, Great Bakkungan and Boan Islands. The northeastern part of Lihiman Island is distinguished for having a more violent kind of mud extrusions mixed with large pieces of rocks, creating a 20-m (66-ft) wide crater on that hilly part of the island. Such extrusions are reported to be accompanied by mild earthquakes and evidence of extruded materials can be found high in the surrounding trees. Submarine mud extrusions off the island have been observed by local residents. ==== Other Asian locations ==== There are a number of mud volcanoes in Xinjiang. There are mud volcanoes at the Minbu Township, Magway Region, Myanmar (Burma). There are two active mud volcanoes in southern Taiwan and several inactive ones. The Wushan Mud Volcanoes are in the Yanchao District of Kaohsiung City. There are active mud volcanoes in Wandan township of Pingtung County. There are mud volcanoes on the island of Pulau Tiga, off the western coast of the Malaysian state of Sabah on Borneo. The Meritam Volcanic Mud, locally called the 'lumpur bebuak', located about 35 kilometres (22 mi) from Limbang, Sarawak, Malaysia is a tourist attraction. A drilling accident offshore of Brunei on Borneo in 1979 caused a mud volcano which took 20 relief wells and nearly 30 years to halt. Active mud volcanoes occur in Oesilo (Oecusse District, East Timor). A mud volcano in Bibiluto (Viqueque District) erupted between 1856 and 1879. === North America === Mud volcanoes of the North American continent include: A field of small (<2 metres (6.6 ft) high) fault-controlled, cold mud volcanoes is on California's Mendocino Coast, near Glenblair and Fort Bragg, California. The fine-grained clay is occasionally harvested by local potters. Shrub and Klawasi mud volcanoes in the Copper River basin by the Wrangell Mountains, Alaska. Emissions are mostly CO2 and nitrogen; the volcanoes are associated with magmatic processes. An unnamed mud volcano 30 metres (98 ft) high and with a top about 100 metres (328 ft) wide, 24 kilometres (15 mi) off Redondo Beach, California, and 800 metres (2,620 ft) under the surface of the Pacific Ocean. A field of small (<3 metres (9.8 ft)) mud volcanoes in the Salton Sea geothermal area near the town of Niland, California. Emissions are mostly CO2. One, known as the Niland Geyser, continues to move erratically. Smooth Ridge mud volcano in 1,000 metres (3,280 ft) of water near Monterey Canyon, California. Kaglulik mud volcano, 43 metres (141 ft) under the surface of the Beaufort Sea, near the northern boundary of Alaska and Canada. Petroleum deposits are believed to exist in the area. Maquinna mud volcano, located 16–18 kilometres (9.9–11.2 mi) west of Vancouver Island, British Columbia, Canada. ==== Yellowstone's "Mud Volcano" ==== The name of Yellowstone National Park's "Mud Volcano" feature and the surrounding area is misleading; it consists of hot springs, mud pots and fumaroles, rather than a true mud volcano. Depending upon the precise definition of the term mud volcano, the Yellowstone formation could be considered a hydrothermal mud volcano cluster. The feature is much less active than in its first recorded description, although the area is quite dynamic. Yellowstone is an active geothermal area with a magma chamber near the surface, and active gases are chiefly steam, carbon dioxide, and hydrogen sulfide. However, there are mud volcanoes and mud geysers elsewhere in Yellowstone. One, the "Vertically Gifted Cyclic Mud Pot" sometimes acts as a geyser, throwing mud up to 30 feet high. The mud volcano feature in Yellowstone was previously a mound until a thermal explosion in the 1800s ripped it apart. ==== Caribbean ==== There are many mud volcanoes in Trinidad and Tobago in the Caribbean, near oil reserves in southern parts of the island of Trinidad. As of 15 August 2007, the mud volcano titled the Moruga Bouffle was said to being spitting up methane gas which shows that it is active. There are several other mud volcanoes in the tropical island which include: the Devil's Woodyard mud volcano near New Grant, Princes Town, Trinidad and Tobago the Moruga Bouffe mud volcano near Moruga the Digity mud volcano in Barrackpore the Piparo mud volcano the Chatham mud volcano underwater in the Columbus Channel; this mud volcano periodically produces a short-lived island. the Erin Bouffe mud volcano near Los Iros beach L'eau Michel mud volcano in Bunsee Trace, PenalA number of large mud volcanoes have been identified on the Barbados accretionary complex, offshore Barbados. === South America === ==== Venezuela ==== The eastern part of Venezuela contains several mud volcanoes (or mud domes), all of them having an origin related to oil deposits. The mud of 6 kilometres (3.7 mi) from Maturín, contains water, biogenic gas, hydrocarbons and an important quantity of salt. Cattle from the savanna often gather around to lick the dried mud for its salt content. ==== Colombia ==== Volcan El Totumo, which marks the division between Bolívar and Atlantico in Colombia. This volcano is approximately 50 feet (15 m) high and can accommodate 10 to 15 people in its crater; many tourists and locals visit this volcano due to the alleged medicinal benefits of the mud; it is next to a cienaga, or lake. This volcano is under legal dispute between the Bolívar and Atlántico Departamentos because of its tourist value. === Africa === === Australasia === ==== New Zealand ==== As well as the Runaruna Mud Volcano the size of the splatter cones associated with some of New Zealands many geothermal mud pools or mudpots might qualify, depending upon definition. == See also == == References == == External links == Origin of mud volcanoes Cold water mud volcanoes created by artesian pressure in Minnesota's Nemadji River basin Bulletin Of Mud Volcanology Azerbaijan Academy Of Sciences (in English) Gaia's Breath—Methane and the Future of Natural Gas Archived 2009-02-12 at the Wayback Machine – USGS, June 2003 Azeri mud volcano flares – October 29, 2001, BBC report Redondo Beach mud volcano with methane hydrate deposits Hydrocarbons Associated with Fluid Venting Process in Monterey Bay, California Hydrothermal Activity and Carbon-Dioxide Discharge at Shrub and Upper Klawasi Mud Volcanoes, Wrangell Mountains, Alaska – U.S. Geological Survey Water-Resources Investigations Report 00-4207 Mud Volcano Eruption at Baratang, Middle Andamans Article on mud volcanoes from Azerbaijan International Mud volcano floods Java, August 2006 Mud volcano work suspended, 25 Feb 2007, Al Jazeera English Possible mud volcano on Mars (BBC News) Of Mud Pots and the End of the San Andreas Fault (Seismo Blog) Mud Volcanoes at West Nile Delta Video by GEOMAR I Helmholtz-Centre for Ocean Research Kiel El Totumo volcano near Cartagena, Colombia on YouTube World's Only Moving Mud Puddle on YouTube showing the progress over time of the Niland Geyser

Landforms

Mudflat

Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal flat ecosystems are as extensive globally as mangroves, covering at least 127,921 km2 (49,391 sq mi) of the Earth's surface. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries; they are also seen in freshwater lakes and salty lakes (or inland seas) alike, wherein many rivers and creeks end. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and aquatic animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily. A recent global remote sensing analysis estimated that approximately 50% of the global extent of tidal flats occurs within eight countries (Indonesia, China, Australia, United States, Canada, India, Brazil, and Myanmar) and that 44% of the world's tidal flats occur within Asia (56,051 km2 or 21,641 sq mi). A 2022 analysis of tidal wetland losses and gains estimates that global tidal flats experienced losses of 7,000 km2 (2,700 sq mi) between 1999 and 2019, which were largely offset by global gains of 6,700 km2 (2,600 sq mi) over the same time period.In the past tidal flats were considered unhealthy, economically unimportant areas and were often dredged and developed into agricultural land.On the Baltic Sea coast of Germany in places, mudflats are exposed not by tidal action, but by wind-action driving water away from the shallows into the sea. This kind of wind-affected mudflat is called Windwatt in German. == Ecology == Tidal flats, along with intertidal salt marshes and mangrove forests, are important ecosystems. They usually support a large population of wildlife, and are a key habitat that allows tens of millions of migratory shorebirds to migrate from breeding sites in the northern hemisphere to non-breeding areas in the southern hemisphere. They are often of vital importance to migratory birds, as well as certain species of crabs, mollusks and fish. In the United Kingdom mudflats have been classified as a Biodiversity Action Plan priority habitat. The maintenance of mudflats is important in preventing coastal erosion. However, mudflats worldwide are under threat from predicted sea level rises, land claims for development, dredging due to shipping purposes, and chemical pollution. In some parts of the world, such as East and South-East Asia, mudflats have been reclaimed for aquaculture, agriculture, and industrial development. For example, around the Yellow Sea region of East Asia, more than 65% of mudflats present in the early 1950s had been destroyed by the late 2000s. It is estimated that up to 16% of the world tidal flats have disappeared since the mid-1980s.Mudflat sediment deposits are focused into the intertidal zone which is composed of a barren zone and marshes. Within these areas are various ratios of sand and mud that make up the sedimentary layers. The associated growth of coastal sediment deposits can be attributed to rates of subsidence along with rates of deposition (example: silt transported via river) and changes in sea level.Barren zones extend from the lowest portion of the intertidal zone to the marsh areas. Beginning in close proximity to the tidal bars, sand dominated layers are prominent and become increasingly muddy throughout the tidal channels. Common bedding types include laminated sand, ripple bedding, and bay mud. Bioturbation also has a strong presence in barren zones. Marshes contain an abundance of herbaceous plants while the sediment layers consist of thin sand and mud layers. Mudcracks are a common as well as wavy bedding planes. Marshes are also the origins of coal/peat layers because of the abundant decaying plant life.Salt pans can be distinguished in that they contain thinly laminated layers of clayey silt. The main source of the silt comes from rivers. Dried up mud along with wind erosion forms silt dunes. When flooding, rain or tides come in, the dried sediment is then re-distributed. == Selected example areas == Arcachon Bay, France Banc d'Arguin, Mauritania Great Rann of Kutch, India Belhaven, East Lothian Scotland, United Kingdom Bridgwater Bay and Morecambe Bay, United Kingdom Cape Cod Bay, Massachusetts, United States Cook Inlet, Alaska, United States Lindisfarne Island, England, United Kingdom Minas Basin, Nova Scotia, Canada Moreton Bay, Queensland, Australia North Slob, Wexford, Ireland Padilla Bay, Washington, United States Plymouth Bay, Massachusetts, United States Port of Tacoma, Washington, United States Port Susan, Warm Beach, Washington, United States Skagit Bay, Washington Snettisham Norfolk England, United Kingdom Wadden Sea: Netherlands, Germany, Denmark West coast of Andros Island, Bahamas Yellow Sea: China, North Korea, South Korea == See also == Herringbone cross beds == References == == External links == Tidal Flats Tidal Flats Field Sites Intertidal Change Explorer

Landforms

Muskeg

Muskeg (Ojibwe: mashkiig; Cree: maskīk; French: fondrière de mousse, lit. moss bog) is a peat-forming ecosystem found in several northern climates, most commonly in Arctic and boreal areas. Muskeg is approximately synonymous with bog or peatland, and is a standard term in Western Canada and Alaska. The term became common in these areas because it is of Cree origin; maskek (ᒪᐢᑫᐠ) meaning "low-lying marsh".Muskeg consists of non-living organic material in various states of decomposition (as peat), ranging from fairly intact sphagnum moss, to sedge peat, to highly decomposed humus. Pieces of wood can make up five to fifteen percent of the peat soil. The water table tends to be near the surface. The sphagnum moss forming it can hold fifteen to thirty times its own weight in water, which allows the spongy wet muskeg to also form on sloping ground. Muskeg patches are ideal habitats for beavers, pitcher plants, agaric mushrooms and a variety of other organisms. == Composition == Muskeg forms because permafrost, clay or bedrock prevents water drainage. The water from rain and snow collects, forming permanently waterlogged vegetation and stagnant pools. Muskeg is wet, acidic, and relatively infertile, which prevents large trees from growing, although stunted shore pine, cottonwood, some species of willow, and black spruce are typically found in these habitats. It needs two conditions to develop: abundant rain and cool summers. A dead plant that falls on dry soil is normally attacked by bacteria and fungi and quickly rots. If the same plant lands in water or on saturated soil, it decomposes differently. Less oxygen is available under water, so aerobic bacteria and fungi fail to colonize the submerged debris effectively. In addition, cool temperatures retard bacterial and fungal growth. This causes slow decomposition, and thus the plant debris gradually accumulates to form peat and eventually muskeg. Depending on the underlying topography of the land, muskeg can reach depths greater than 30 metres (100 ft). == Description == Although at first glance muskeg resembles a plain covered with short grasses, a closer look reveals a bizarre and almost unearthly landscape. Small stands of stunted and often dead trees, which vaguely resemble bonsai, grow where land protrudes above the water table, with small pools of water stained dark red scattered about. Its grassland appearance invites the unwary to walk on it, but even the most solid muskeg is spongy and waterlogged. Traveling through muskeg is a strange and dangerous experience for the unaccustomed. Muskeg can grow atop bodies of water, especially small ponds and streams. Because of the water beneath, the muskeg surface sometimes ripples underfoot. Thinner patches allow large animals to fall through, becoming trapped under the muskeg and drowning. Moose are at a special disadvantage in muskeg due to their long legs, minimal hoof area, and great weight. Hunters and hikers may occasionally encounter young moose in muskeg-covered ponds submerged up to their torsos or necks, having been unaware of the unstable ground. == Surface strength == Muskeg can be a significant impediment to transportation. During the 1870s, muskeg in Northern Ontario was reported to have swallowed a railroad engine whole when a track was laid on muskeg instead of clearing down to bedrock.Many other instances have been reported of heavy construction equipment vanishing into muskeg in the spring as the frozen muskeg beneath the vehicle thawed. Construction in muskeg-laden areas sometimes requires the complete removal of the soil and filling with gravel. If the muskeg is not completely cleared to bedrock, its high water content will cause buckling and distortion from winter freezing, much like permafrost. One method of working atop muskeg is to place large logs on the ground, covered with a thick layer of clay or other stable material. This is commonly called a corduroy road. To increase the effectiveness of the corduroy, prevent erosion, and allow removal of material with less disturbance to the muskeg, a geotextile fabric is sometimes placed down before the logs. However temporary winter access roads on muskeg (ice road), created by clearing the insulating snow and allowing the muskeg to freeze, are more commonly used as they are cheaper to construct and easier to decommission. Water is often sprayed on these roads to thicken the ice allowing heavy trucks and equipment to safely access remote sites in the winter. == In fiction == In Jack London's short story, "Love of Life," the starving protagonist eats muskeg berries along the trail. "A muskeg berry is a bit of seed enclosed in a bit of water. In the mouth the water melts away and the seed chews sharp and bitter. The man knew there was no nourishment in the berries, but he chewed them patiently with a hope greater than knowledge and defying experience." Also, in Rick Riordan's young adult novel The Son of Neptune, one of the protagonists accidentally gets swallowed by muskeg soil as a trap laid by the Earth goddess Gaia. Gordon Lightfoot references muskeg in his song "Canadian Railroad Trilogy". In Martha Ostenso's novel Wild Geese, the land owned and beloved by the antagonist plays an important role: "Southeast, under the ridge, bottomless and foul, lay the muskeg, the sore to Caleb's eye. In the heat of summer it gave up sickly vapours in which clouds of mosquitoes rose. Cattle and horses, breaking through the pasture fence and heading for the hay field, had disappeared beneath its spongy surface." (p. 12) == Gallery == == Sources == C. Michael Hogan. 2008. Black Spruce: Picea mariana, GlobalTwitcher.com, ed. Nicklas Stromberg, November, 2008 "What on Earth is Muskeg?". Forest Facts. Tongass National Forest. 25 August 2000. Archived from the original on 14 January 2012. == References ==

Landforms

One-Line Sky

One-line sky or single-line sky refers to the landform of a narrow passage between huge rocks, where the sky looks like a single line. It is a word often used in China and the Chinese cultural sphere.One-line sky is found in the following areas: Huangshan, Anhui Province Wuyi Mountains, Fujian Province Shoushan, Kaohsiung, Taiwan == See also == Slot canyon == References ==

Landforms

Paleocollapse

Paleocollapse is a rock structure resembling the karst landform, but is formed essentially by the dissolution of underlying sedimentary rock. It has also been called paleo-karst collapse. This has the effect of collapsing the formerly intact rock above, forming extensive fractures, debris pipes, and open caverns. Normally, the process was started and completed in the geologic past. The mechanism of its formation is relatively simple. As in the illustration, a deeper layer of salt (or other evaporite) is dissolved, through some process. The support for the upper rock vanishes, and starts the collapse process. This is much like the subsidence associated with old coal mines. Eventually, the caving process reaches the surface, and can be associated with debris pipes, rock fractures, and open caverns. At some later date, undisturbed sediments, or glacial till may fill the collapse zone. Paleocollapse geology can be remarkably stable (unlike karst), but poses some serious challenges to engineering or environmental geology. Primarily, the collapse zone is extremely permeable. This can provide a conduit for groundwater, or contaminant transport. As well, these zones may only be marginally stable, in that they can be reactivated by human activity, or events such as earthquakes. In China, underground mines have become suddenly flooded, due to paleocollapse features. In order to fully characterize the hazard, investigations may be undertaken, using dye tracers, or exploration geophysics. Of particular importance is understanding the true stability of the region. The paleocollapse process may continue at some future date, due to deep groundwater flow changes. Or perhaps, the reason that a certain evaporite zone has dissolved, is because of underlying faults in the bedrock. == References ==

Landforms

Panhole

A panhole is a depression or basin eroded into flat or gently sloping cohesive rock. Similar terms for this feature are gnamma or rock holes (Australia), armchair hollows, weathering pans (or pits) and solution pans (or pits).Some authors refer to panholes also as potholes, which is a term typically used for similarly shaped riverine landforms. In fluvial geomorphology, the term pothole is typically used for a smooth, bowl-shaped or cylindrical hollow, generally deeper than wide, found developed in the rocky bed of a stream. This type of feature is created by the grinding action either of a stone or stones or of coarse sediment whirled around and kept in motion by eddies or the force of the stream current in a given spot. == Description of panholes == Panholes are erosional or destructional features that are developed in a variety of climatic environments and in a wide range of rock types. These shallow basins, or closed depressions, are quite commonly well developed in surfaces of granitic rocks and sandstone. They are generally characterized by flat bottoms and sometimes by overhanging sides. The initial form may be a closed hollow created by a patch of humus. Diameters are rarely greater than 6 ft (1.8 m). Some panholes were at one time thought to be man-made because their roundness was so perfect they were argued not be natural and must have been shaped by humans.Panholes are most commonly found in desert environments such as the Colorado Plateau. A few well-known panholes are found developed in sandstone surfaces in Canyonlands National Park, Capitol Reef National Park, and Moab. Panholes are capable of collecting water when it rains, freezing over when the weather gets cold, dry out in hotter weather, and can even contain some species of bacteria, lichens, mosses, and blue-green algae. Panholes range in size from a few centimeters to many meters in diameter. The cavities can be shallow or more than 15 meters (49 ft) deep, containing hundreds of liters of water. The Australian Aboriginal term gnamma, in particular, implies a depression capable of holding water in arid areas, forming an important water resource for Aboriginal people that needed to be carefully maintained.Within the potholes is a varied eco-system that contains bacteria such as cyanobacteria, fungi, and algae which can be referred as biofilm. Potholes do not contain predators like fish or aquatic insect. The biofilm breaks down some of the siliceous minerals in the pothole for nutrients resulting in furthering the weathering the pothole. The organisms that live in the potholes have to tolerate rapid change in water temperature, pH, oxygen, carbon dioxide concentration, and ion concentration. == Origin of panholes == In the Sierra Nevada, California these features were termed weathering pits by François E. Matthes, where they are thought to indicate rock surfaces that are unglaciated or escaped more recent glaciations. In Sierra Nevada granitic rocks, these features have a characteristic shape such that they expand more rapidly in width than they grow in depth. One explanation for their conformation is because the most active environment for weathering is the zone of alternate wetting and drying along the margins of the pools that collect in the pits, the margins tend to deepen and enlarge until all points of the bottom are equally wet or dry at the same time, thus producing their characteristic shape. Potholes can expand from weathering and erosion but the main activity of how potholes expand is from biological weathering. At one time the belief was that the only agents involved with the expansion of potholes were physical weathering. == Terminology == === Australia === In Australia, the terms "gnamma" and "rock hole" (or "rockhole") are used. Gnamma is an anglicization of a Nyoongar language word, used by that Aboriginal people of Western Australia to describe a naturally formed rock hole as well as its retained rainwater. The term "gnamma hole" is also widely used, but is incorrect, being a tautology. == Locations == === Australia === Hiltaba Nature Reserve === United States === Beam Rocks, Forbes State Forest, Pennsylvania Glacier Point, Yosemite National Park, California Navajo National Monument, Arizona Shenandoah National Park, Virginia Stone Mountain, Georgia Stone Mountain (North Carolina), North Carolina == References ==

Landforms

Pediment (geology)

A pediment, also known as a concave slope or waning slope, is a very gently sloping (0.5°-7°) inclined bedrock surface. It is typically a concave surface sloping down from the base of a steeper retreating desert cliff, escarpment, or surrounding a monadnock or inselberg, but may persist after the higher terrain has eroded away.Pediments are erosional surfaces. A pediment develops when sheets of running water (sheet floods) wash over it in intense rainfall events. It may be thinly covered with fluvial gravel that has washed over it from the foot of mountains produced by cliff retreat erosion.A pediment is not to be confused with a bajada, which is a merged group of alluvial fans. Bajadas also slope gently from an escarpment, but are composed of material eroded from canyons in the escarpment and redeposited on the bajada, rather than of bedrock with a thin veneer of gravel. == Description == Pediments were originally recognized as the upper part of smoothly sloping (0.5°-7°) concave piedmont surfaces surrounding mountains in arid regions. The lower part of the piedmont is a bajada, with the distinction being that the upper pediment surface is cut into bedrock (with possibly a thin veneer of alluvium) and is thus a result of erosion, while the lower bajada is aggradational (formed by accumulation of fresh sediments). Above the pediment, the slope abruptly increases, with an angle of 15° to nearly vertical. This creates a well-defined knickpoint at the base of the higher terrain.The lower part of the pediment may be buried under younger bajada deposits. This is described as a concealed pediment. An originally level pediment that is subsequently dissected is described as a dissected pediment, though the term has also been applied to bedrock surfaces that were never level.It is not uncommon to find isolated erosional remnants on a pediment.Individual pediments formed where canyons emerge from the high ground may merge to form coalescing pediments that may remain when the higher terrain is entirely eroded away. Coalescence of pediments over a large area results in a pediplain. A pediplain is distinguished from a peneplain because a pediplain has a thin veneer of gravel and is relatively steep, while a peneplain is surfaced with deep residual soil and is extremely level, with slopes of less than 55 feet per mile (10 meters per km). It has even been suggested that there are no true peneplains, and most identified peneplains are actually pediplains. == Occurrence == Pediments are commonly found in arid to semiarid climates and are particularly well known from the western United States. However, they are also found along the forearc of the Andes in South America and in South Africa. More recently, it has been recognized that pediments are formed in temperate and humid climates and in a variety of tectonic settings, and that the character of the bedrock is not critical to their formation.Ancient pediments surfaces have been found in the geologic record as far back as the Proterozoic. == Processes responsible for carving pediments == The processes responsible for creating a pediment, and especially for creating a sharp knickpoint at the juncture of the pediment with higher terrain, have been debated for over a century. It is now recognized that pediments are found in humid as well as arid climates, in many tectonic settings, and on many varieties of bedrock. They are nonetheless not universal features of mountain fronts. This realization has prompted renewed efforts to explain their formation, including through numerical modeling.Proposed mechanisms of formation include: Sheetwash or sheet erosion, in which broad sheets of flowing water evenly remove thin layers of surface material without incising channels. Mountain-front retreating by weathering Lateral planation or erosion by a stream Rillwash or rill erosion, in which flow is concentrated in numerous closely spaced minute channels.Later researchers looked to a combination of these mechanisms to explain pedimentation. In numerical models that couple granitic bedrock weathering and episodic stream transport of sediments, pediments emerge spontaneously. Pediment formation is promoted by arid conditions that hinder vegetation, reduce soil cohesion, and contribute to channel bank instability. Localized flooding on terrain with high infiltration rates also promotes pedimentation. These conditions all reduce incision rates. The models correctly predict that pediments are more common in hydrologically open basins than in hydrologically closed basins. == History == In 1877 Grove Karl Gilbert first observed pediments in the Henry Mountains in Utah. He described the formation as "hills of planation cut across the upturned edges of tilted beds". Gilbert believed the origin of pediments in the Henry Mountains are due to stream planation and active erosion of deserts. This theory was advocated by Sydney Paige (1912), and Douglas Johnson (1932). Johnson identified three zones of pediments. == References ==

Landforms

Peninsula

A peninsula (from Latin paeninsula; from paene 'almost', and insula 'island') is a landform that extends from a mainland and is surrounded by water on most, but not all of its borders. A peninsula is also sometimes defined as a piece of land bordered by water on three of its sides. Peninsulas exist on all continents. The size of a peninsula can range from tiny to very large. The largest peninsula in the world is the Arabian Peninsula. Peninsulas form due to a variety of causes. == Etymology == Peninsula derives from Latin paeninsula, which is translated as 'peninsula'. Paeninsula itself was derived from paene 'almost', and insula 'island', or together, 'almost an island'. The word entered English in the 16th century. == Definitions == A peninsula is usually defined as a piece of land surrounded on most, but not all sides, by water, but is sometimes instead defined as a piece of land bordered by water on three of its sides.A peninsula may be bordered by more than one body of water, and the body of water does not have to be an ocean or a sea. A piece of land on a very tight river bend or one between two rivers is sometimes said to form a peninsula, for example in the New Barbadoes Neck in New Jersey, United States. A peninsula may be connected to the mainland via an isthmus, for example, in the isthmus of Corinth which connects to the Peloponnese peninsula. == Formation and types == Peninsulas can be formed from continental drift, glacial erosion, glacial meltwater, glacial deposition, marine sediment, marine transgressions, volcanoes, divergent boundaries or river sedimentation. More than one factor may play into the formation of a peninsula. For example, in the case of Florida, continental drift, marine sediment, and marine transgressions were all contributing factors to its shape. === Glaciers === In the case of formation from glaciers (e.g., the Antarctic Peninsula or Cape Cod), peninsulas can be created due to glacial erosion, meltwater or deposition. If erosion formed the peninsula, softer and harder rocks were present, and since the glacier only erodes softer rock, it formed a basin. This may create peninsulas, and occurred for example in the Keweenaw Peninsula.In the case of formation from meltwater, melting glaciers deposit sediment and form moraines, which act as dams for the meltwater. This may create bodies of water that surround the land, forming peninsulas.If deposition formed the peninsula, the peninsula was composed of sedimentary rock, which was created from a large deposit of glacial drift. The hill of drift becomes a peninsula if the hill formed near water but was still connected to the mainland, for example during the formation of Cape Cod about 23,000 years ago. === Others === In the case of formation from volcanoes, when a volcano erupts magma near water, it may form a peninsula (e.g., the Alaskan Peninsula). Peninsulas formed from volcanoes are especially common when the volcano erupts near shallow water. Marine sediment may form peninsulas by the creation of limestone. A rift peninsula may form as a result of a divergent boundary in plate tectonics (e.g. the Arabian Peninsula), while a convergent boundary may also form peninsulas (e.g. Gibraltar or the Indian subcontinent). Peninsulas can also form due to sedimentation in rivers. When a river carrying sediment flows into an ocean, the sediment is deposited, forming a delta peninsula.Marine transgressions (changes in sea level) may form peninsulas, but also may affect existing peninsulas. For example, the water level may change, which causes a peninsula to become an island during high water levels. Similarly, wet weather causing higher water levels make peninsulas appear smaller, while dry weather make them appear larger. Sea level rise from global warming will permanently reduce the size of some peninsulas over time. == Uses == Peninsulas are noted for their use as shelter for humans and Neanderthals. The landform is advantageous because it gives hunting access to both land and sea animals. They can also serve as markers of nation's borders. == List of peninsulas == == See also == Barrier island Cape Headland Promontory Salient Spit Tidal island == References == === Bibliography === == External links == The dictionary definition of peninsula at Wiktionary

Landforms

Pillar (landform)

A pillar is a landform, either of rock or earth, defined by the USGS as: "Vertical, standing, often spire-shaped, natural rock formation (chimney, monument, pinnacle, pohaku, rock tower)." Some examples of rock pillars are Chambers Pillar, Katskhi pillar, Pompeys Pillar, and Pillar Rock. The Oxford Dictionary of Geography defines earth pillar as: "An upstanding, free column of soil that has been sheltered from erosion by a natural cap of stone on the top. They are common where boulder-rich moraines have been subject to gully erosion, as in parts of the southern Tyrol." A Hoodoo is another type of earth pillar. Examples of earth pillars are Awa Sand Pillars and Đavolja Varoš. == See also == Glossary of geology – List of definitions of geological terminology == References ==

Landforms

Pinge

A Pinge ([ˈpɪŋə], plural: Pingen) or Binge ("binger") is the name given in German-speaking Europe to a wedge-, ditch- or funnel-shaped depression in the terrain caused by mining activity. This depression or sink-hole is frequently caused by the collapse of old underground mine workings that are close to the Earth's surface. Unlike natural landforms, a Pinge is a direct result of human activity. The term has no direct equivalent in English, but may be translated as "mining sink-hole", "mine slump" or, in some cases, as "glory hole". == Origin of the word == In the original sense of the word, the mining terms Pinge or Binge go back to the activity known as pingen which meant something like "prospecting". An aufgepingter lode was one near the surface of the ground. The Pinge was therefore like a primitive, open pit mine.Subsequently, the term was transferred to the funnel-shaped depressions that formed at the surface above filled or collapsed mineshafts. In lode mining, shafts and pits followed the strike of the lode and left behind the typical lines of Pingen (Pingenzüge) associated with medieval mining that may still be seen, for example, in the Thuringian Forest, the Upper Harz Mountains, the Ore Mountains and the Eschweiler area in central Europe. Later on, the term Pinge was applied to many kinds of depression left in the terrain as a result of mining activity, including the holes left by opencast pits in surface mining or the cave-ins above underground mines. The latter occurred either as a result of the unexpected consequences of active mining (often associated with accidents or disasters) or the subsidence above abandoned mines. They were sometimes willingly and knowingly accepted, for example, when mining was carried out by a method known as block caving. A Pingenzug is a row of several Pingen in succession. == Types == A Pinge can arise in different ways. In some cases it is caused by surface excavation. In other cases it follows the extraction of mineral deposits at a shallow depth and the associated collapse of the overburden that can result in subsidence at the surface. Pingen caused by surface mining generally date to the 16th and 17th centuries and are mostly only 0.5 - 1 metre deep. Deeper Pingen, caused by collapse of the overburden, date to the 18th and 19th centuries. The Pinge, which is caused as a result of the subsidence of the surface of the terrain, is usually surrounded by a ring-shaped mound (German: Halde). A number of Pingen form trenches up to 250 metres long and 15 metres wide. === Excavation === Initially, the extraction of ore or coal took place near the surface at outcrops of the main deposits. Excavations of seam-like deposits were carried out by digging out bowl-shaped depressions, the so-called Pütts, that miners hewed out along the course of the seam with picks and shovels. Once digging reached the water table, groundwater ran into the hole. If the quantity of water was so great that it entered the pit faster than it could be drained, the holes filled up with groundwater. To make matters worse, the ingress of water and the consequent softening of the soil reduced the stability of the side walls. For this reason, the pit was simply abandoned in such cases and a new one dug some distance away. Over the years, these hollows became Pingen. In the southern Ruhr, there are numerous such Pingen caused by surface mining. Subsequent erosion and collapse has produced funnel-shaped hollows, the Pingen. Where Pingen have resulted from surface mining, small ring-shaped tips were often made by dumping the waste rock. Another origin of Pingen occurred in a method of lignite mining called Kuhlenbau or "pit mining". Here, the brown coal was extracted by means of small, square, open pit known as a Kuhle. As one pit was exhausted, it was filled with spoil from the next. In this way, a row of several hollows or Pingen was created. === Collapse === Pingen were also caused by the mining of a lode near the surface that was not properly supported. When a deposit is exploited through underground mining, there are pressures and strains along the hanging walls. Over time, the hanging wall slips along the tear line into the mine cavity. Pingen are mining sink-holes covering a small area. But just like the continual, large-scale subsidence caused by large-scale mining at great depths, the overburden of mines near the surface collapses at regular intervals along a tear line. This subsidence of the strata is usually accompanied by an audible mining shockwave (Bergschlag). The actual shape of the Pinge is primarily determined by the different rock formations. In addition, the shape and appearance of Pingen is influenced by their age. A Pinge which is only shallow and only gently shaped over its entire surface is usually older than a Pinge with sharp contours.How quickly an underground cavity near the surface collapses is dependent on various factors. Key criteria are the depth and the stability of the overburden. The depth of the Pinge is essentially determined by the size of the cavity created. If larger voids are created at less depth as in the mining technique known as Tummelbau ("underground pit mining"), the Pinge can be several metres deep. This sort of mining damage is particularly problematic if it occurs in a populated area. ==== Schachtpinge ==== A Schachtpinge ("shaft pinge") is a particular type of Pinge caused by the collapsing of old surface mineshafts. Especially in the early days of mining, very many smaller mineshafts were sunk. The shafts were predominantly lined with mine timber. Only in rare cases was natural stone, brick or concrete used for this purpose. If these wells were then abandoned, the wooden lining rotted over the years, fell away and then the pit collapsed, leading to the formation of a Schachtpinge. The diameter and depth of a Schachtpinge depends on the size of the shafts, and whether the shaft had been filled in and the quality of the infill. Another cause for the emergence of a Schachtpinge was so-called Duckelbau mining. In this type of mining, the overburden in the area of the shaft usually collapsed very quickly, because ore was dug out just a few metres below the surface and, in most cases, not in solid rock. ==== Stollenpinge ==== A Stollenpinge is caused by the collapse of parts of a mining gallery (Stollen) that is usually located at levels close to the surface or in weathered rock. They are generally easily recognizable from their typical asymmetrical shape and their shape of the depression which, unlike Pingen caused by excavations, is normally greater on the uphill side as well as their rather large mounds. == Examples of well-known Pingen == The following Pingen were formed by the collapse of overburden. Altenberg (Germany) the first collapses occurred as early as 1545 as a result of the uncontrolled mining (by fire-setting) of the Altenberg tin ore mountain. Later on, ore was extracted both from the solid rock as well as the broken rock mass. As a result of continued, unchecked fire-setting of the solid rock, there was a significant amount of further excavation which was unable to withstand the pressure of the overburden. In 1578, 1583, 1587 and 1619 there were further collapses, although it is not clear whether these were caused deliberately. The largest occurred on 24 January 1620. This destroyed 36 pits and created a funnel-shaped hole on the surface that covered 2 hectares. In the following centuries, mining was continued by extracting the broken rock "from below" until 1991. Further fractures took place, initially uncontrolled, but later planned. As a result, the Altenberg Pinge grew 150 m deep and 450 m in diameter, covering an area of 12 ha by the time tin ore working ceased. Today the Great Pinge is not only one of the attractions of the town of Altenberg, but was also designated in May 2006 by the Academy of Geosciences at Hanover as one of the 77 most important national geotopes in Germany.Falun (Sweden) Uncontrolled copper mining at the Great Copper Mountain led in 1687 to a large-scale collapse of the mine. The resulting Pinge, known as Stora Stöten, is today 95 m deep and 350 m wide. Geyer (Germany) The Geyersche Binge (50.621108°N 12.928289°E / 50.621108; 12.928289) was caused by intensive overworking of the pits under the Geyersberg hill. In 1704, after a cavern up to 35 m high and, at its foot, 40 metres wide had been dug out, the first big cave-in occurred at the surface. This was followed by others up to 1803. The last disastrous collapse happened on 11 May 1803. It led to the cessation of underground mining. From 1851 a quarry firm mined the broken rock in the Binge. When that closed in 1935 the Binge was made a nature reserve. Today it is 50–60 metres deep and covers an area of about 200 by 250 metres.Plattenberg (Czech Republic) At Plattenberg there are 2 well-known Pingen (50.398689°N 12.778473°E / 50.398689; 12.778473), relicts of an old tin mine. The Eispinge ("Ice Pinge", Czech: Ledová Jáma) was caused by the collapse of a gallery. The name of this natural monument is due to its ravine-like shape. All year round, heavy, cold and damp air sinks down to the floor of the crevice which is only one metre wide, but 15–20 metres deep. Light, warm air never penetrates it. As a result, cave ice and snow lie all year round in the Pinge. In 1813, snow and ice from the Eispinge were transported as far as Leipzig to be used in the care of the wounded at the Battle of Leipzig. The appearance of the neighbouring Wolfspinge ("Wolf's Pinge", Czech: Vlčí Jáma) goes back to the collapse of the old Wolfgang Pit. It is about 200 m long, up to 45 m wide and up to 25 m deep.Seiffen (Germany) In Seiffen near the church are two neighbouring sink-holes up to 34 metres deep above the old tin mine that are called the Geyerin and Neuglücker Stockwerkspinge. They were probably formed in the 16th century as a result of fire-setting. As in Altenberg, mining carried on even after the collapse. Unlike Altenberg, however, the rubble was mined at the surface using a gantry crane (Förderbrücke). Mining operations shut down in the 19th century. Since 1934, there has been an open-air stage in the Geyerin. (50.646266°N 13.453879°E / 50.646266; 13.453879). == See also == Caldera Cenote Ponor Sinkhole == Footnotes == == References == == External links == Josef Stiny: Zur Entstehung von Kohlenmulden. (pdf; 330 kB)

Landforms

Pinnacle (geology)

A pinnacle, tower, spire, needle or natural tower (German: Felsnadel, Felsturm or Felszinne) in geology is an individual column of rock, isolated from other rocks or groups of rocks, in the shape of a vertical shaft or spire. Examples are the summits of the Aiguille du Midi in the Mont Blanc massif in France, the almost 43-metre-high Barbarine on the south side of the Pfaffenstein hill near Königstein in Germany, or the Bischofsmütze, the Drei Zinnen and the Vajolet Towers in the Dolomites, which are rich in such towers. An area of limestone formations within Nambung National Park, near the town of Cervantes, Western Australia, is known as The Pinnacles. == Gallery == == See also == Hoodoo Kigilyakh Pinnacles National Park Pyramidal peak Stack (geology) Totem pole (Monument Valley) Trango Towers == External links ==

Landforms

Polar desert

Polar deserts are the regions of Earth that fall under an ice cap climate (EF under the Köppen classification). Despite rainfall totals low enough to normally classify as a desert, polar deserts are distinguished from true deserts (BWh or BWk under the Köppen classification) by low annual temperatures and evapotranspiration. Most polar deserts are covered in ice sheets, ice fields, or ice caps, and they are also called white deserts.Polar deserts are one of two polar biomes, the other being Arctic tundra. These biomes are located at the poles of Earth, covering much of the Antarctic in the southern hemisphere, and in the northern hemisphere extending from the Arctic into North America, Europe and Asia. Unlike the tundra that can support plant and animal life in the summer, polar deserts are largely barren environments, comprising permanent, flat layers of ice; due to the scarcity of liquid water, the same is also true of the few ice-free areas. However, there is evidence of some life in this seemingly inhospitable landscape: sediments of organic and inorganic substances in the thick ice hosting microbial organisms closely related to cyanobacteria, able to fix carbon dioxide from the melting water.Temperature changes in polar deserts frequently cross the freezing point of water. This "freeze-thaw" alternation forms patterned textures on the ground, as much as 5 m (16 ft) in diameter. Most of the interior of Antarctica is polar desert, despite the thick ice cover. Conversely, the McMurdo Dry Valleys of Antarctica, although they have had no ice for thousands of years due to katabatic wind but contain ephemeral streams and hypersaline lakes characteristic of extreme non-polar deserts, are not necessarily polar desert.Polar deserts are relatively common during ice ages, as ice ages tend to be dry. Climate scientists have voiced concerns about the effects of global warming to the ice poles in these polar biomes. == See also == Desert Desertification List of deserts by area List of deserts by continent Tundra == References == This article incorporates public domain material from Types of Deserts. United States Geological Survey.

Landforms

Polje

A polje, also called karst polje or karst field, is a large flat plain found in karstic geological regions of the world, with areas usually in the range of 5–400 km2 (2–154 sq mi). The name derives from the Slavic languages, where polje literally means 'field', whereas in English polje specifically refers to a karst plain or karst field. == In geology == A polje, in geological terminology, is a large, flat-floored depression within karst limestone, whose long axis develops in parallel with major structural trends and can become several miles (tens of kilometers) long. Superficial deposits tend to accumulate along the floor. Drainage may be either by surface watercourses (as an open polje) or by swallow holes (as a closed polje) or ponors. Usually, the ponors cannot transmit entire flood flows, so many poljes become wet-season lakes. The structure of some poljes is related to the geological structure, but others are purely the result of lateral dissolution and planation. The development of poljes is fostered by any blockage in the karst drainage.A polje covers the flatbottomed lands of closed basins which may extend over large areas, up to 1,000 km2. The flat floor of a polje may consist of bare limestone, of a nonsoluble formation (as with rolling topography), or of soil. A polje typically shows complex hydrogeological characteristics such as exsurgences, estavelles, swallow holes, and lost rivers. In colloquial use, the term "polje" designates flat-bottomed lands which are overgrown or are under cultivation. The Dinaric Karst has many poljes.They are mostly distributed in subtropical and tropical latitudes but some also appear in temperate or, rarely, boreal regions. Usually covered with thick sediments, called "terra rossa", they are used extensively for agricultural purposes. Some poljes of the Dinaric Alps are inundated during the rainy winters and spring seasons as masses of water called izvor or vrelo appears at the margins. The water disappears through shafts called ponor. Prominent karst poljes are Livanjsko polje (about 60 km long and 7 km wide), Glamočko Polje, Grahovsko Polje, Drvarsko Polje, Duvanjsko Polje, Kupreška Visoravan (Kupres Highlands), Popovo Polje, Dabarsko Polje, Nevesinjsko Polje and Gatačko Polje in Bosnia and Herzegovina; Logatec, Planina, and Cerknica Polje in Slovenia; Grahovsko Polje and Nikšićko Polje in Montenegro; Ličko Polje and Krbava in Lika, Croatia; Begovo Pole in North Macedonia and Odorovsko polje the only karst polje in Serbia. In Portugal, the town of Minde is located in a landscape of intensive karst. In the summer the polje is fertile fields, in winter, in case of heavy rain, a temporary lake. Compare also Lake Copais in Boeotia in Greece. == Etymology == In its original languages, the word is synonymous with interior valley. The word polje (Cyrillic: поље) itself is of Slavic origin (best known as the root for the country Poland, Polska, from the Polish word pole 'field'). English borrowed polje from Slovene or Serbo-Croatian (Cyrillic: поље, pronounced [pôʎe]). The equivalent in neighbouring Macedonian and Bulgarian is pole (поле), and in Russian it is polye (поле). As a borrowing, apart from English it can be found in a number of languages including: French, German, Greek, Italian, Spanish and Turkish (which uses polye). == Notes ==

Landforms

Polonyna (montane meadow)

Polonyna (Ukrainian: полонина, romanized: polonyna; Rusyn: полонина, romanized: polonyna; Polish: połonina; Slovak: polonina) is a specific, regionally-focused geographic term, that is used as a designation for areas of montane meadows (a landform type) in the upper subalpine or alpine zones of the Carpathian Mountains. The term polonyna was introduced to English from Slavic languages, in order to designate various mountainous regions, mainly in the Eastern Carpathians, and also in the Western Carpathians. The polonyna type areas of montane meadows are very frequent in the Outer Eastern Carpathians, particularly in the Eastern Beskids. Throughout history, they were used for pasture, and in modern times they have become a popular destination for various forms of recreational tourism.The noun polonyna (plur. polonynas) and its corresponding adjectives (anglicized as polonyne or polonynian) are also used frequently in local toponyms throughout the Carpathian region. One of two main mountain ranges of the Eastern Beskids is known as the Polonyne Beskids or Polonynian Beskids (Ukrainian: Полонинські Бескиди; Polish: Beskidy Połonińskie), and it includes several mountains that also contain the same term in their names, like: Smooth Polonyna (Polish: Połonina Równa; Ukrainian: Полонина Рівна), Polonyna Borzhava (Polish: Połonina Borżawska; Ukrainian: Полонина Боржава), Red Polonyna (Polish: Połonina Czerwona; Ukrainian: Червонa Полонина), etc. == See also == == References == == Sources == Földvary, Gábor Z. (1988). Geology of the Carpathian Region. Singapore: World Scientific Publishing Company. ISBN 9789813103825. Tasenkevich, Lydia (2009). "Polonynas: Highlands Pastures in the Ukrainian Carpathians". Grasslands in Europe: Of High Nature Value. Zeist: KNNV Publishing. pp. 203–208. ISBN 9789004278103. == Further reading == Андрій Л. Байцар, "Полонини Українських Карпат" (Adriy L. Baytsar, Polonynas of the Ukrainian Carpathians), in: Генеза, географія та екологія ґрунтів: Збірник наукових праць Міжнародної конференції (Genesis, Geography and Ecology of Soils: Collection of Scientific Papers from the International Conference). Львів, 1999. - P. 107-109. Андрій Л. Байцар, "Полонини Українських Карпат: генезис, поширення та морфологія" (Adriy L. Baytsar, Polonynas of the Ukrainian Carpathians: Genesis, Distribution, and Morphology), Вісник Львівського університету: Серія географічна, 29 (2003) - P. 3-6. == External links == Encyclopedia of Ukraine: Polonynian Beskyd Encyclopedia of Ukraine: Borzhava Encyclopedia of Ukraine: Krasna Encyclopedia of Ukraine: Svydivets Encyclopedia of Ukraine: Chornohora Encyclopedia of Ukraine: Skole Beskyd National Nature Park

Landforms

Pothole (landform)

In Earth science, a pothole is a smooth, bowl-shaped or cylindrical hollow, generally deeper than wide, found carved into the rocky bed of a watercourse. Other names used for riverine potholes are pot, (stream) kettle, giant's kettle, evorsion, hollow, rock mill, churn hole, eddy mill, and kolk. Although somewhat related to a pothole in origin, a plunge pool (or plunge basin or waterfall lake) is the deep depression in a stream bed at the base of a waterfall. It is created by the erosional forces of turbulence generated by water falling on rocks at a waterfall's base where the water impacts. Potholes are also sometimes referred to as swirlholes. This word was created to avoid confusion with an English term for a vertical or steeply inclined karstic shaft in limestone. However, given widespread usage of this term for a type of fluvial sculpted bedrock landform, pothole is preferred in usage to swirlhole. The term pothole is also used to refer to other types of depressions and basins that differ in origin. For example, some authors refer to panholes found in the Colorado Plateau also as potholes. Other terms used for panholes are gnamma (Australia), opferkessel (German, roughly “sacrificial basin”), armchair hollows, weathering pans (or pits) and solution pans or solution pits. In another case, the term pothole is used to refer to a shallow depression, generally less than 10-acre (4.0 ha) in area that occurs between dunes or on subdued morainic relief on a prairie, as in Minnesota and the Dakotas, and often contains an intermittent pond or marsh that serves as a nesting place for waterfowl. == Origin == The consensus of geomorphologists and sedimentologists is that fluvial potholes are created by the grinding action of either a stone or stones or coarse sediment (sand, gravel, pebbles, boulders), whirled around and kept in motion by eddies within and force of the stream current in a given spot. Being a spectacular feature of bedrock river channels, they have been and still are studied extensively and considered as a key factor in bedrock channel development and morphology and important factor in the incision of bedrock channels. == References ==

Landforms

Prairie lake

A prairie lake is a somewhat shallow lake that will empty naturally during dry seasons, allowing a variety of terrestrial plants to flourish upon the rich nutrients in the exposed lakebed, and the lakes eventually refill with water returning to their previous aquatic state. In northern Florida, a flatwoods/prairie lake is generally a shallow basin in flatlands with high water table and often with sinkholes. These lakes frequently have a broad littoral zone; still water or flow-through; sand or peat substrate; variable water chemistry, but characteristically colored to clear, acidic to slightly alkaline, soft to moderately hard water with moderate mineral content sodium, chloride, sulfate; oligo-mesotrophic to eutrophic. These lakes are often associated with aquifers. Northern Florida has four large prairie lakes: Lake Lafayette, Lake Jackson, Lake Iamonia, and Lake Miccosukee. During the antebellum period in Florida, cotton plantation owners used these lakes to graze cattle, sheep, and other animals when dry. Prairie lakes also exist in the upper midwestern United States in Iowa, Montana, and Minnesota in Black Rush Lake, and Lake Shaokatan, a shallow prairie lake in west central Lincoln County. The geology may be different from those in Florida. == Resources == Florida Natural Areas Inventory Paisley, Clifton; From Cotton To Quail, University of Florida Press, c1968. EPA study University of Minnesota

Landforms

Pressure ridge (ice)

A pressure ridge, when consisting of ice, is a linear pile-up of sea ice fragments formed in pack ice by accumulation in the convergence between floes. Such a pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Within sea ice expanses, pressure ridges originate from the interaction between floes, as they collide with each other. Currents and winds are the main driving forces, but the latter is particularly effective when they have a predominant direction. Pressure ridges are made up of angular ice blocks of various sizes that pile up on the floes. The part of the ridge that is above the water surface is known as the sail; that below it as the keel. Pressure ridges are the thickest sea ice features and account for up to 30-40% of the total sea ice area and about one-half of the total sea ice volume. Stamukhi are pressure ridges that are grounded and that result from the interaction between fast ice and the drifting pack ice. Similar to undeformed ice, pressure ridges can be first-, second-, and multiyear depending on how many melt seasons they managed to survive. Ridges can be formed from ice of different ages, but mostly consist of 20-40 cm thick blocks of thin and young ice. == Internal structure == The blocks making up pressure ridges are mostly from the thinner ice floe involved in the interaction, but it can also include pieces from the other floe if it is not too thick. In the summer, the ridge can undergo a significant amount of weathering, which turns it into a smooth hill. During this process, the ice loses its salinity (as a result of brine drainage and meltwater flushing). This is known as an aged ridge. A fully consolidated ridge is one whose base has undergone complete freezing. The term consolidated layer is used to designate freezing up of the rubble just below the water line. The existence of a consolidated layer depends on air temperature — in this layer, the water between individual blocks is frozen, with a resulting reduction in porosity and an increase in mechanical strength. A keel's depth of an ice ridge is much higher than its sail's height - typically about 3-5 times. The keel is also 2-3 times wider than the sail. Ridges are usually melting faster than level ice, both at the surface and at the bottom. Sea-ice ridges also play an important role in confining meltwater within under-ice meltwater layers, which may lead to the formation of false bottoms. == Thickness and consolidation == One of the largest pressure ridges on record had a sail extending 12 m above the water surface, and a keel depth of 45 m. The total thickness for a multiyear ridge was reported to be 40 m. On average, total thickness ranges between 5 m and 30 m, with a mean sail height that remains below 2 m. The average keel depth of Arctic ridges is 4.5 m. The sail height is usually proportional to the square root of the ridge block thickness. Ice ridges in Fram Strait usually have a trapezoidal shape with a bottom horizontal section covering around 17% of the total ridge width and with a mean draft of 7 m, while ice ridges in the Chukchi and Beaufort Seas have a concave close to triangular shape.The average consolidated layer thickness of Arctic ridges is 1.6 m. Usually, ridges are consolidating faster than level ice because of their initial macroporosity. Ridge rubble porosity (or water-filled void fraction of ridge unconsolidated part) is in the wide range of 10-40%. During winter, ice ridges are consolidating up to two times faster than level ice, with the ratio of level ice and consolidated layer thickness proportional to the square root of ridge rubble porosity. This results in 1.6-1.8 ratio of consolidated layer and level ice thickness by the end of winter season. Meanwhile, snow is usually about three times thicker above ridges than above level ice. Sometimes ridges can be found fully consolidated with the total thickness up to 8 m. Ridges may also contain from 6% to 11% of snow mass fraction, which can be potentially linked to the mechanisms of ridge consolidation. Fram Strait ridge observations suggest, that the largest part of ridge consolidation happens during the spring season when during warm air intrusions or dynamic events snow can enter ridge keels via open leads and increase the speed of ridge consolidation. These observations are supported by high snow mass fraction in refrozen leads, observed during the spring season. The ridge consolidation potentially reduces light levels and the habitable space available for organisms, which may have negative ecological impacts as ridges have been identified as ecological hotspots. == Characterization methods == The physical characterization of pressure ridges can be done using the following methods: Mechanical drilling of the ice with non-coring or coring augers (when the ice core is retrieved for analysis). Surveying, whereby a level, theodolite or a differential GPS system is used to determine sail geometry. Thermal drilling – drilling involving melting of the ice. Observation of the ice canopy by scuba divers. Upward looking sonars and multibeam sonars fixed on seabed or moounted on a remotely operated underwater vehicle. A series of thermistors (ice mass balance buoy), to monitor temperature changes. Electromagnetic induction, from the ice surface or from an aircraft. == Interest for pressure ridges == From an offshore engineering and naval perspective, there are three reasons why pressure ridges are a subject of investigation. Firstly, because the highest loads applied on offshore structures operating in cold oceans by drift ice are associated with these features. Secondly, when pressure ridges drift into shallower areas, their keel may come into contact with the seabed, thereby representing a risk for subsea pipelines (see Seabed gouging by ice) and other seabed installations. Thirdly, they have a significant impact on navigation. In the Arctic, ridged ice makes up about 40% of the overall mass of sea ice. First-year ridges with large macroporosity are important for the ice-associated sympagic communities and identified as potential ecological hotspots and proposed to serve as refugia of ice-associated organisms. == See also == Finger rafting Iceberg Ice volcano Offshore geotechnical engineering == Notes == == References ==

Landforms

Promontory

A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the softer rock to the sides of it, or are the high ground that remains between two river valleys where they form a confluence. A headland, or head, is a type of promontory. == Promontories in history == Located at the edge of a landmass, promontories offer a natural defense against enemies, as they are often surrounded by water and difficult to access. Many ancient and modern forts and castles have been built on promontories for this reason. One of the most famous examples of promontory forts is the Citadel of Namur in Belgium. Located at the confluence of the Meuse and Sambre rivers, the citadel has been a prime fortified location since the 10th century. The surrounding rivers act as a natural moat, making it difficult for enemies to access the fort. Another example of a promontory fort is Fort Pitt, which was built by the English during the American Revolution on the site of the former Fort Duquesne, which belonged to the French during the French and Indian War. The fort was located at the confluence of the Allegheny and Monongahela rivers, providing an additional layer of defense. The surrounding area eventually became the city of Pittsburgh, Pennsylvania. In Ireland, many promontory forts were built by the ancient Celts for defense against invaders. These forts were often located on isolated peninsulas or headlands and were difficult to access, making them ideal for defending against enemy attacks. The ancient town of Ras Bar Balla in southern Somalia is another example of a promontory fort. Located on a small promontory, the town was part of the Ajuran Sultanate's domain during the Middle Ages and was strategically located to defend against potential invaders. == See also == Isthmus – Narrow strip of land connecting two larger land areas == References == == External links == The dictionary definition of promontory at Wiktionary

Landforms

Purple moor grass and rush pastures

Purple moor grass and rush pastures is a type of Biodiversity Action Plan habitat in the UK. It occurs on poorly drained neutral and acidic soils of the lowlands and upland fringe. It is found in the South West of England, especially in Devon. The vegetation consists of species-rich, semi-natural grassland containing abundant purple moor grass (Molinia caerulea) and one or more of several creeping rushes: sharp-flowered rush (Juncus acutiflorus), jointed rush (Juncus articulatus) and blunt-flowered rush (Juncus subnodulosus). Only 8% remains of the area thought to have existed in 1900. In the UK estimate the area is thought to be less than 70,000 hectares (170,000 acres). Their importance is recognised and are included as a priority habitat in the United Kingdom Biodiversity Action Plan. == Etymology == In Devon and Cornwall it is known as culm grassland, after the Culm Measures on which it is predominantly found. In East Anglia it is known as litter meadow due to the practice of cutting it for bedding. In Wales it is known as rhôs pasture. == Typical grasses == Common bent (Agrostis capillaris), crested dog's-tail (Cynosurus cristatus), floating sweet grass (Glyceria fluitans), marsh foxtail (Alopecurus geniculatus), purple moor grass (Molinia caerulea), red fescue (Festuca rubra), sweet vernal grass (Anthoxanthum odoratum). == Characteristic species == The Natural England Higher Level Stewardship Farm Environmental Plan handbook defines the habitat as grassland with at least two of the following species are found frequently, with another two being found occasionally. Bog asphodel (Narthecium ossifragum) Bog mosses (Sphagnum spp) Bog pimpernel (Anagallis tenella) Bugle (Ajuga reptans) Common valerian (Valeriana officinalis) Common meadow-rue (Thalictrum flavum) Cross-leaved heath (Erica tetralix) Devil's-bit scabious (Succisa pratensis) Globeflower (Trollius europaeus) Greater burnet (Sanguisorba officinalis) Greater bird's foot trefoil (Lotus pedunculatus) Hemp-agrimony (Eupatorium cannabinum) Jointed rush (Juncus articulatus) Lesser spearwort (Ranunculus flammula) Lesser water-parsnip (Berula erecta) Lousewort (Pedicularis sylvatica) Fen bedstraw (Galium uliginosum) Marsh bedstraw (Galium palustre) Marsh cinquefoil (Potentilla palustris) Marsh hawk's-beard (Crepis paludosa) Marsh-marigold (Caltha palustris) Marsh pennywort (Hydrocotyle vulgaris) Marsh valerian (Valeriana dioica) Marsh violet (Viola palustris) Meadow thistle (Cirsium dissectum) Meadowsweet (Filipendula ulmaria) Orchids (Orchidaceae) Ragged robin (Lychnis flos-cuculi) Rough hawkbit (Leontodon hispidus) Saw-wort (Serratula tinctoria) Sneezewort (Achillea ptarmica) Tormentil (Potentilla erecta) Water avens (Geum rivale) Water mint (Mentha aquatica) Whorled Caraway (Carum verticillatum) Wild angelica (Angelica sylvaticum) Small blue-green sedges: glaucous sedge (Carex flacca), common sedge (Carex nigra), carnation sedge (Carex panicea) etc. Yellow flag (Iris pseudacorus) == Key animal species associated with purple moor grass and rush pastures == Marsh fritillary butterfly (Eurodryas aurinia), uses scattered scrub and carr in September/October. Brown hairstreak (Theccla betulae) Narrow-bordered bee hawkmoth (Hemaris tityus) - fly during April/May, during the day. Eurasian curlew (Numenius arquata) - lays eggs in April/May in open ground on a mound or tussock, incubates them through to June, and young may not be ready to fly until late July or into August. Common snipe (Gallinago gallinago) Barn owl (Tyto alba) Marbled white (Melanargia galathea) on the wing in June/July. Reed bunting (Emberiza schoeniclus) uses scattered scrub and carr in September/October. == British National Vegetative Classification == The main British National Vegetation Classification communities associated with purple moor grass and rush pastures include M23 (Juncus effusus/acutiflorus-Galium palustre rush pasture), M25 (Molinia caerulea-Potentilla erecta mire), M26 (Molinia caerulea-Crepis paludosa mire) and British NVC community MG10 (Holco-Juncetum effusi rush-pasture). == Threats == Drainage Cultivation Fertiliser application Overgrazing Frequent burning Undergrazing - leading to succession to scrub and woodland. Can become dominated by soft rush (Juncus effusus) Afforestation == Management == Natural England Guidance advocates an average grass height of 7 and 8 centimetres (2.8 and 3.1 in) for rush during April and May, increasing to 10 and 13 centimetres (3.9 and 5.1 in) in June to October, a quarter of the sward no more than 15 centimetres (5.9 in) for grass and 40 centimetres (16 in) for rushes - a diverse sward of shorter areas interspersed by taller tussocks.Areas of dense litter are beneficial to overwintering insects and small mammals, but should be less than 25% of the total area in October. == Protection == In the UK there are a number of initiatives to help prevent deterioration and to restore these sites. These include designation as Site of Special Scientific Interest, national nature reserves, voluntary entry into the Environmental Stewardship Scheme by landowners, or work by voluntary conservation organisations such as the Devon Wildlife Trust. The largest area of Culm grassland in Devon is Hare's Down, Knowstone & Rackenford Moors near Rackenford and is owned by Devon Wildlife Trust. Their management regime includes controlled burning in winter and light grazing by cattle in the summer. The aim is to control the amounts of scrub and bracken without removing them completely. == References == == External links == Magic mapping system showing purple moor grass and rush pasture locations in the UK

Landforms

Reef knoll

A reef knoll is a land-based landform that comprises an immense pile of calcareous material that accumulated on a previously existing ancient sea floor. At the time of its accumulation it may have had enough structure from organisms such as sponges to have been free-standing and to withstand the sea currents as material accumulated, and was likely an atoll. Another possibility is the remains of deep water coral. Such structures are thus often fossil-rich. A bioherm is a sedimentary rocky landform enclosed or surrounded by rock of different origin. A biostrome is a distinctly bedded or broadly lenticular sedimentary rocky landform. Krumbein defines these terms as types of stromatolites: "Distinctly bedded, widely extensive, blanketlike build-ups are biostromes. Nodular, biscuit-like, dome-shaped or columnar stromatolites are also referred to as bioherms". == England == Examples on the Derbyshire/Staffordshire border include Thorpe Cloud and Bunster Hill in southern Dovedale, and also Chrome Hill and Parkhouse Hill at the northern end. These structures are often most clearly seen where the surrounding rocks are much softer and so can be preferentially eroded. All the Derbyshire examples quoted lie at the edge of the limestone areas; Chrome and Parkhouse lie at the divide between limestone and the much softer shale. Examples in the Yorkshire Dales lie on the downthrow side (north) of the Mid Craven Fault. There is one set located around Thorpe (Skelterton, Butter Haw, Stebden, Elbolton, Thorpe Kail, Myra Bank and Hartlington Kail); one set located around Malham (Burns Hill, Cawden, and Wedber); and a set around Settle (High Hill and Scaleber). It was once proposed that in Lancashire, reef knolls could be seen between the villages of Worston and Downham near Clitheroe. == See also == Waulsortian mudmound == References == == External links == British Geological Survey website, on Chrome, Parkhouse and Derbyshire atolls

Landforms

Ridge and swale

Ridge and swale, or in dunal areas dune and swale, is a landform consisting of regular, parallel ridges alternating with marshy depressions. Ridge-and-swale landscapes are most commonly formed by the gradual movement of a beach, for example as a result of gradually fluctuating water levels, or the shifting meanders of a river. In the river context, ridge-and-swale landscapes are commonly formed by scroll bars. They are also found along ocean coasts, for example on the Outer Banks of North Carolina. == Great Lakes ridge and swale == Freshwater ridge-and-swale ecosystems are globally rare and found only in parts of the Great Lakes of North America. They were formed as a result of the gradual retreat of beaches due to falling water levels and post-glacial rebound. The swales and the adjoining lake or river commonly form a single hydrological unit, so that rising or falling lake levels will cause water levels in the swales to rise or fall as well. Most ridge-and-swale landscapes have been destroyed as a result of the massive industrial development found in many former ridge-and-swale areas, such as the Calumet Region of Northwest Indiana. However, some extensive dune-and-swale complexes persist in Michigan, such as at the Michigan Wilderness State Park. The remaining dune-and-swale complexes along the Great Lakes are often home to extremely rare plants and animals, such as the endangered Karner Blue butterfly. In the Calumet Region, the difficulty of moving equipment through dune-and-swale topography greatly slowed industrial development, but could not stop it after the turn of the 20th century. The few remnants are preserved as nature preserves, including the Gibson Woods county park in Hessville, Indiana, the Miller Woods section of the Indiana Dunes National Park, and additional preserves operated by The Nature Conservancy and Shirley Heinze Land Trust. == Works cited == Kenneth Schoon (2016). Shifting Sands: The Restoration of the Calumet Area. ISBN 9780253023407. == References == == External links == Wooded dune and swale complex

Landforms

Rolling hills (geology)

Landforms

Saddle (landform)

The saddle between two hills or mountains is the region surrounding the saddle point, the lowest point on the line tracing the drainage divide (the col) connecting the peaks. When, and if, the saddle is navigable, even if only on foot, the saddle of a (optimal) pass between the two massifs, is the area generally found around the lowest route on which one could pass between the two summits, which includes that point which is a mathematically when graphed a relative high along one axis, and a relative low in the perpendicular axis, simultaneously; that point being by definition the col of the saddle. == Topography == A saddle is the lowest area between two highlands (prominences or peaks) which has two wings which span the divide (the line between the two prominences) by crossing the divide at an angle, and, so is concurrently the local highpoint of the land surface which falls off in the lower direction. That is, the drainage divide is a ridge along the high point of the saddle, as well as between the two peaks and so defines the major reference axis. A saddle can vary from a sharp, narrow gap to a broad, comfortable, sway-backed, shallow valley so long as it is both the high point in the sloping faces which descends to lower elevations and the low area between the two (or three or four.) flanking summits. Concurrently, along a different axis, it is the low point between two peaks, so as such, is the likely 'optimal' high point in a pass if the saddle is traversed by a track, road or railway. === Saddles and cols === The relationship between saddles and cols is not universally agreed. A col is sometimes defined as the lowest point on a saddle co-linear with the drainage divide that connects the peaks. Whittow describes a saddle as "low point or col on a ridge between two summits", whilst the Oxford Dictionary of English implies that a col is the lowest point on the saddle. Monkhouse describes a saddle as a "broad, flat col in a ridge between two mountain summits." The term col tends to be associated more with mountain, rather than hill, ranges.The height of a summit above its highest saddle (called the key saddle) is effectively a measure of a hill's prominence, an important measure of the independence of its summit. Saddles lie on the line of the watershed between two hills. == Structural geology == In structural geology, a saddle is a depression located along the axial trend of an anticline. == Mathematical saddles == A 'saddle point' in mathematics derives its name from the fact that the prototypical example in two dimensions is a surface that curves up in one direction, and curves down in a different direction, resembling a riding saddle or a mountain pass between two peaks forming a landform saddle. == Notes == == References ==

Landforms

Salt surface structures

Salt surface structures are extensions of salt tectonics that form at the Earth's surface when either diapirs or salt sheets pierce through the overlying strata. They can occur in any location where there are salt deposits, namely in cratonic basins, synrift basins, passive margins and collisional margins. These are environments where mass quantities of water collect and then evaporate; leaving behind salt and other evaporites to form sedimentary beds. When there is a difference in pressure, such as additional sediment in a particular area, the salt beds – due to the unique ability of salt to behave as a fluid under pressure – form into new structures. Sometimes, these new bodies form subhorizontal or moderately dipping structures over a younger stratigraphic unit, which are called allochthonous salt bodies or salt surface structures. == Salt == === Tectonic environments === Four key environments can facilitate salt deposition. These places allow salt-bearing water to collect and evaporate, leaving behind bedded deposits of solidified salt crystals. Below are short descriptions of these environments and a few examples. Convergent boundaries – Areas where two plates collide; if there is water trapped between the two, there is the possibility of evaporation and deposition. The Mediterranean Sea, particularly during the Messinian salinity crisis, is a prime example. Rifted boundaries/passive margins – Also known as divergent boundaries, these areas begin as rift basins, where extension is pulling apart the crust. If this rifting allows water to flood the resulting valley, salt deposition can occur. Examples include the Campos Basin, Brazil, Kwanza Basin, West Africa, and the Gulf of Mexico. Cratonic basins – Within continental boundaries, salt deposition can occur anywhere that bodies of water can collect. Even away from ocean sources, water is capable of dissolving and carrying ions that can later precipitate as salts, and when the water evaporates, the salts are left behind. Examples of these basins are the South Oman Salt Basin and the Michigan Basin. In the past, there was a great shallow sea covering most of the Great Plains region of the United States; when this sea dried up, it created the Strataca deposit now mined in Kansas, among others. === Characteristics === Salt has two key characteristics that make it unique in a tectonic setting, and important economically. The first is that salt (and other evaporites) deform plastically over geologic time, and thus behaves as a fluid rather than a rigid structure. This allows structures with salt components to deform more easily and have a slightly different appearance. Take, for example the Appalachians, which contain some salt deposits, and the Rocky Mountains, which is an accretionary terrain with little to no salt. This also allows for the creation of structural traps for oil and gas, as well as metals which makes them sought after targets in industry. The second, which is the fact that evaporites are often less dense, or more buoyant, than the surrounding rock, which aids in its mobility and creates a Rayleigh Taylor instability. This means that the less dense substance will find a way to rise through or away from the more dense one. In salt tectonics, this occurs in three ways; the first is differential loading, where the salt flows from an area of high pressure to lower pressure, the second is gravitational spreading, where the salt spreads out laterally under its own gravitational weight, the last is thermal convection, where warmer – and thus less dense – salt rises through colder and more dense salt. This is only seen in laboratory settings due to the unlikely occurrence of salt bodies with great enough temperature variance. == Evolution histories == In order for originally horizontal beds to form the allochthonous salts, they must first break free of their geological restraints. The first base structure can be formed in a combination of six ways: Reactive piercement – a normal fault synrift relieves pressure above the salt layer. This causes the salt to flow into the area of lower pressure to maintain its equilibrium. Active piercement – salt moves through sediments where there are no structures to take advantage of. Erosional piercement – overlying sediments are eroded away, revealing the present salt dome. Thrust piercement – local thrust faults apply force to salt sheets which follow the path of least resistance up the footwall of the fault. Ductile piercement – not so much a 'piercing' movement, but local differential pressure force the salt to rise through weaker overlying sediments. Occurs due to the Rayleigh-Taylor instability created by salt's low density. Passive piercement – after the salt column has initially pierced the overlying sediments, the rate it rises matches or supersedes the growing sediment layers.From here there are three paths that a forming surface structure can take. Two stem from a diapir base, and the third from a sheet base. The sheet becomes a source-fed thrust, not unlike the thrust piercement, it takes advantage of local fault planes to rise. The difference between the two diapir bases, is that one, termed a plug-fed thrust, has a sediment cap over the top, preventing the salt from freely flowing until building pressure forces it through the cap; the other, a plug-fed extrusion, lacks the sediment cap and is allowed to flow freely. == Types of surface structures == Once the salt structure has reached the surface, it is termed one of four names; salt-wing intrusions, extrusive advance, open-toed advance or thrust advance. There is a certain level of transition between the four, as some process, such as the dissolution and removal of salt, deposition of new sediment, erosion and thrusting can shift the characteristics between them. === Salt-wing intrusions === Salt-wing intrusions are technically underground structures; found in shortening, or compressional, systems, they form radial salt wedges between detached bedding planes. However, the caps on them can be eroded away, revealing the salt and transforming it into an extrusive advance. === Extrusive advance === Extrusive advances begin once the diapir reaches the ground's surface and the salt is exposed. The salt then spreads from the feeder under gravitational pressure alone. This flowing has two consequences that form the structure. First, as the top of the salt flows faster than the bottom, there is a frontal roll along the leading edge. Second, the salt overrides any sediment being deposited at the same time, causing the feature to climb upsection and prograde. Over time, some of the salt is dissolved away, leaving a layer of impurities and other sediments behind, the thickness of this roof, or sediment cap, depends on the percentage of impurities in the salt and the sedimentation rate of the area. === Thrust advance === Thrust advances return to salt sheets as their primary base structure, and form because salt provides a weak detachment layer for faulting systems. When force is applied in such systems, the buried sheet will advance along the hanging wall. There are three driving processes in this type of advance; gravitational pressure of both the salt and overlying sediments, spreading of the margin and general plate tectonics. === Open-toed advance === Open-toed advances can either evolve from the dissolution of salts from an extrusive advance structure, or it could have evolved from a plug-fed thrust. They are partially buried advances where only the advancing edge, called the toe, is open to flow, which is controlled by a combination of gravitational forces and differential pressure of the overlying sediments. There are three described sediment roof types: synclinal basins – isolated patches of consolidated sediments, prograding roof – a growing sheet of sediments, and salt breakout – where the salt had to force its way through the overlying sediments. == References ==

Landforms

Sand island

A sand island is an island that is mostly made of sand. The largest sand island in the world is Fraser Island, Australia. Other examples of large sand islands are Moreton, North Stradbroke and Bribie Islands which lie south of Fraser Island off the east coast of Brisbane, Australia. == References ==

Landforms

Sandfall

Sandfall (sand fall or grainfall) is a term applied to a variety of forms of sedimentary transport or sedimentary features belonging to the larger category of mass wasting, and are driven by wind, water currents and gravitational forces. One, sometimes spectacular, form is superficially similar to waterfalls and may be found under dry, desert conditions or in submarine conditions. The sand either falls vertically over suitable drops or cascades down hard slopes. The process has been described as "dry sandflows cascading down the escarpment face, where the grain concentration decreases dramatically and the streaming component of stress greatly exceeds the collisional component" Sandfalls are found in sandstone canyons such as Antelope Canyon. A similar process occurs in submarine environments driven by water currents and gravity. Sandfalls on a large scale occur off the southern tip of the island of Mauritius, where strong ocean currents move sand from the high coastal shelf over the edge and into the abyssal depths. Sandfalls in the submarine San Lucas Canyon off Cabo San Lucas, Baja California were dived by Jacques Cousteau. Carter (1975) argues that the ubiquity of this process is evident from the examples from the sides of submarine canyons documented by Dill (1964) and from seamounts and deep-sea trenches documented by Heezen and Holhster (1971).Also sometimes referred to as sandfall, is the movement of sand on the "steeply sloping surface on the lee side of a dune standing at or near the angle of repose of loose sand and advancing downwind by a succession of slides wherever that angle is exceeded."The process of sand falling like rain has also been referred to as a sandfall. == References == == External links == sand falls have u seen that before ?????? – YouTube Sand Falls Cabo San Lucas – YouTube Sand Falls – Photograph at BetterPhoto.com

Landforms

Schlatt (landform)

Schlatt or Flatt is the Lower Saxon name for a heathland pond, an undrained body of water usually shallow, that is fed by surface water and is largely unaffected by ground water. The water is impounded by a water-retentive layer. Most Schlatts can dry out from time to time. Schlatts are characteristic of the nutrient-poor geest ridges of the North German Plain. Most of them were formed as wind-blown hollows in the periglacial region of the last ice age. The term is of Lower Saxon origin and is used mainly for the ponds in that part of Germany. In the district of Diepholz (Lower Saxony) the Conservation Foundation (Stiftung Naturschutz) has taken upon itself the preservation of Schlatts as part of a Schlatt programme. Using volunteers working with the land owners and farmers over 300 small ponds and Schlatts have been cleaned up and maintained in order to preserve them as habitats for threatened animal and plant species. == Sources == === Literature === Jan Höper: Flora und Vegetation von Kleingewässern in landwirtschaftlich genutzten Bereichen des Landkreises Diepholz. Diplomarbeit, Göttingen 1999, 129 S. Georg Müller: "Was ist ein Schlatt", Entstehung-Entwicklung-Zustand und rechtliche Hinweise. Broschüre 16 Seiten, Ganderkesee 2009 www.wallhecke.de == External links == Schlatt programme (in German) Plant species in Schlatts (in German) Forgotten Schlatts (in German) Schlatt information (in German) Was ist ein Schlatt? (in German)