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53-412: The volcanic field covers an area of approximately 965 square miles (2,500 km) and contains about 300 maars and diatremes . The erosional exposure of the deposits varies with those in the eastern portion exhibiting the shallowly eroded maar deposits and those in the western portion the more deeply eroded feeder diatremes. The maars result from explosive interaction of the hot diatreme material with

106-481: 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

159-456: 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

212-497: A broad definition: 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 range from slightly acidic to slightly basic, while bogs are always acidic because precipitation lacks

265-812: 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

318-612: 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. Bogs are widely distributed in cold, temperate climes , mostly in boreal ecosystems in

371-620: A mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme . The name maar comes from a Moselle Franconian dialect word used for the circular lakes of the Daun area of Germany. The word evolved from its first use in German in the modern geological sense in 1819 and is now used in English and in the geological sciences as the term for the explosion crater, even if water from rainfall might always have drained from

424-534: 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

477-527: A roothold. The result is a narrow, permanently wet habitat. 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")

530-402: 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: In cool climates with consistently high rainfall (on more than c. 235 days a year),

583-469: A volcanic crater, is a maar. The carbon dioxide -saturated Lake Nyos in northwestern Cameroon is another example, as is Zuñi Salt Lake in New Mexico , a shallow saline lake that occupies a flat-floored crater about 6,500 ft (2,000 m) across and 400 ft (120 m) deep. Its low rim is composed of loose pieces of basaltic lava and wall rocks ( sandstone , shale , limestone ) of

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636-642: Is Kagamiike Pond as well as many on the volcanic island of Miyake-jima , Izu Islands (Furumio, Mi'ike, Mizutamari, Shinmio). Koranga Maar and Numundo Maar are in Papua New Guinea . Kawah Masemo maar is on Mount Sempu volcano in Indonesia. The San Pablo Volcanic Field in the Province of Laguna on the island of Luzon in the Philippines contains maars. The Newer Volcanics Province in

689-515: Is a broad, low- relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma ). A maar characteristically fills with water to form a relatively shallow crater lake , which may also be called a maar. Maars range in size from 20 to 3,000  m (66 to 9,800  ft ) across and from 5 to 200 m (20 to 700 ft) deep. Most maars fill with water to form natural lakes. Most maars have low rims composed of

742-538: 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 bayhead 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

795-581: The Auckland volcanic field has other easily accessible maars such as the Mangere Lagoon , Orakei Basin , Panmure Basin , and Pukaki Lagoon . Elsewhere a recent example, only 4000 years old, is Lake Rotokawau in the Bay of Plenty Region . Bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials – often mosses , typically sphagnum moss. It

848-1123: The Butajiri - Silti -Volcanic Field, Ethiopia, the Bayuda Volcanic Field in the Sudan and Lake Nyos in the Oku Volcanic Field in Cameroon). In Saudi Arabia the Al Wahbah crater formed as a result of a maar eruption. In Japan there are maars in the Kirishima - Yaku volcanic field in the Kirishima-Yaku National Park on Kyushu . These include the several maars of the Ibusuki volcanic field such as Lake Unagi . On Honshu in Myōkō-Togakushi Renzan National Park there

901-651: The Eifel region of Germany (where they were originally described), and in other geologically young volcanic regions of Earth. Elsewhere in Europe, La Vestide du Pal, a maar in the Ardèche department of France, is easily visible from the ground or air. Kilbourne Hole and Hunt's Hole, in southern New Mexico near El Paso, Texas , are maars. The Crocodile Lake in Los Baños in the Philippines, though originally thought to be

954-675: 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

1007-1318: 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

1060-803: The Province of Ciudad Real . Active maars were commonplace in Fife and Lothian , Scotland during the Carboniferous period. The location of one such maar was Elie Ness. Active maar volcanoes are mainly known outside Europe. In the US there are numerous maar areas, such as in Alaska ( Ukinrek maars , Nunivak in the Bering Sea ); in Washington ( Battle Ground Lake ); in Oregon ( Fort Rock basin with

1113-883: The Swabian Jura and the Albvorland (the Swabian Volcano) there are maar-forming volcanoes. Because the over 350 eruption points were only active in the Upper Miocene 17 to 11 million years ago, all the maars, apart from the dry maar, Randecker Maar and the Molach, are only detectable geologically. In the Ore Mountains near Hammerunterwiesenthal , the Hammerunterwiesenthal Maar formed about 30 million years ago during

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1166-464: 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. The peat in bogs is an important place for the storage of carbon. If

1219-416: 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

1272-523: The Congo , discovered a peat bog "as big as England " which stretches into neighboring Democratic Republic of Congo . 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

1325-552: The Eifel and Volcanic Eifel there are numerous dry maars: The following volcanic features are often colloquially referred to as a "maar" or "maar lake", although they are not, strictly speaking, maars: In Germany there are also several maars outside of the Eifel. A well-known example is the Messel pit , a former maar lake near Messel in the county of Darmstadt-Dieburg and which is known for its well preserved fossils . In addition in

1378-715: The Oligocene; the maar measures 2 kilometres from east to west and 1.4 kilometres from north to south. The Chaîne des Puys in France contains numerous maars; Lake Albano in the Alban Mountains is a complex maar, and there is also a submarine maar ( Kolumbo ) near Santorini in Greece. The Campo de Calatrava Volcanic Field in Spain contains numerous maars; a typical example being the maar of Hoya del Mortero at Poblete in

1431-567: The States of South Australia and Victoria , Australia, has numerous maars, such as Mount Gambier , Mount Schank and Tower Hill , whose complex system of nested maars is enclosed by one of the largest maars in the world. Foulden Maar in Otago , New Zealand , is an important fossil site, but there are many more maars in New Zealand. As already mentioned these include Lake Pupuke , but

1484-518: The combination of low nutrient levels and waterlogging. 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

1537-511: The crater after the formation event. This extension in meaning was due to recognising that the lake may no longer exist. Since maar lakes are formed after initially ground or subsurface water interacts with a magma intrusion to create an explosion crater, the name came to be used for the crater type as well. The present definition of the term relates to both its common and scientific discourse use in language over two centuries. Depending upon context there may be other descriptors available to use in

1590-400: 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. 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

1643-558: The dissolved minerals (e.g. calcium , magnesium , carbonate ) that act to buffer the natural acidity of atmospheric carbon dioxide . Geography and geology both impact the hydrology: as groundwater mineral content reflects the bedrock geology, there can be great deal of variability in some common ions (e.g. manganese , iron ) while proximity to coastal areas is associated with higher sulfate and sodium concentrations. There are many highly specialized animals, fungi, and plants associated with bog habitat. Most are capable of tolerating

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1696-460: 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 glauca ) 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

1749-765: The explosive reaction that occurs when magma comes into contact with permafrost . Hydromagmatic eruptions are increasingly explosive when the ratio of water to magma is low. Since permafrost melts slowly, it provides a steady source of water to the eruption while keeping the water to magma ratio low. This produces the prolonged, explosive eruptions that created these large maars. Examples of the Seward Peninsula maars include North Killeak Maar, South Killeak Maar, Devil Mountain Maar and Whitefish Maar. Maars occur in western North America, Patagonia in South America,

1802-420: The geological sciences such as the term tuff ring or maar-diatreme volcanoes. These last are volcanoes produced by explosive eruptions that cut deeply into the country rock with the maar being " the crater cut into the ground and surrounded by an ejecta ring ". A 2011 geological clarification of a maar is " Maar volcanoes are distinguished from other small volcanoes in having craters with their floor lying below

1855-553: 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. Bog habitats may develop in various situations, depending on the climate and topography. Bogs may be classified on their topography, proximity to water, method of recharge, and nutrient accumulation. These develop in gently sloping valleys or hollows. A layer of peat fills

1908-421: 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

1961-698: The groundwater system and result in a mixture of volcanic tuff material and sediments of the Miocene – Pliocene lacustrine sediments of the Bidahochi Formation . In the western portion of the field the buttes consist of the feeder diatremes of monchiquite and nepheline syenite magmas . Most of the volcanic activity occurred between 8.5 and 6 million years ago, with the most recent dated at 4.2 million years ago. 35°28′03″N 110°11′32″W  /  35.46750°N 110.19222°W  / 35.46750; -110.19222 Maar A maar

2014-469: 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

2067-840: The headwaters of large rivers. Even the enormous Yangtze River arises in the Ruoergai peatland near its headwaters in Tibet . 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. The anaerobic environment and presence of tannic acids within bogs can result in

2120-521: 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. 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

2173-536: The hollow. The largest known maars are found at Espenberg on the Seward Peninsula in northwest Alaska. These maars range in size from 4 to 8 km (2.5 to 5.0 mi) in diameter and a depth up to 300 m (980 ft). These eruptions occurred in a period of about 100,000 years, with the youngest (the Devil Mountain Maar) occurring about 17,500 years ago. Their large size is due to

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2226-640: The latter is the Eckfelder Maar . Near Steffeln is the Eichholzmaar (also called the Gussweiher ) which has dried out during the last century and is being renaturalised into a maar. In some cases the underlying rock is so porous that maar lakes are unable to form. After winters of heavy snow and rainfall many dry maars fill partially and temporarily with water; others contain small bogs or often artificial ponds that, however, only occupy part of

2279-497: 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

2332-408: 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. 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

2385-768: The maars of Big Hole , Hole-in-the-Ground , Table Rock ); in Death Valley National Park , California ( Ubehebe Crater ); in Nevada ( Soda Lakes ); as well as the maars of the White Rock Canyon , Mount Taylor , the Potrillo volcanic fields ( Kilbourne Hole and Hunt's Hole ), and Zuñi Salt Lake in New Mexico. In Central Mexico, the Tarascan volcanic field contains several maars in

2438-475: 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. 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

2491-426: The pre-eruptive surface ". Maar lakes , also referred to simply as maars , occur when groundwater or precipitation fills the funnel-shaped and usually round hollow of the maar depression formed by volcanic explosions. Examples of these types of maar are the three maars at Daun in the Eifel mountains of Germany . A dry maar results when a maar lake dries out, becomes aggraded or silted up . An example of

2544-613: 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 . 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

2597-680: The states of Michoacán and Guanajuato . In Nicaragua is the maar of Laguna de Xiloa, part of the Apoyeque volcano. From South America, there are known maars in Chile (e.g. Cerro Overo and Cerro Tujle in northern Chile). Jayu Khota is a maar in Bolivia . The maar of Birket Ram lies on the Golan Heights ; further south maars occur in Africa ( Bilate Volcanic Field and Haro Maja in

2650-781: The underlying diatreme , as well as chunks of ancient crystalline rocks blasted upward from great depths. Maars in Canada are found in the Wells Gray-Clearwater volcanic field of east-central British Columbia and in kimberlite fields throughout Canada. Another field of maars is found in the Pali-Aike Volcanic Field in Patagonia , South America. and in the Sudanese Bayuda Volcanic Field . The Auckland volcanic field in

2703-590: The urban area of Auckland , New Zealand, has several maars, including the readily accessible Lake Pupuke in the North Shore suburb of Takapuna . Arizona 's Meteor Crater was for many years thought to be a maar of volcanic origin but it is now known to be an impact crater . In the Volcanic Eifel there are about 75 maars. Both lake-filled and dry maars are typical, though the latter are more common. The last eruptions took place at least 11,000 years ago, and many maars are older, as evidenced by their heavy erosion and less obvious shapes and volcanic features. In

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2756-401: The water surface to cover bays or even entire small lakes. Bogs at the edges of lakes may become detached and form floating islands . 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

2809-401: 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

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