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Maars
A maar 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.David S.G. Thomas and Andrew Goudie (eds.), ''The Dictionary of Physical Geography'' (Oxford: Blackwell, 2000), 301. . Maars range in size from across and from deep. Most maars fill with water to form natural lakes. Most maars have low rims composed of a mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme. Etymology 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 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maar USGS
A maar is a broad, low-Terrain, 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 Volcanic crater lake, crater lake, which may also be called a maar.David S.G. Thomas and Andrew Goudie (eds.), ''The Dictionary of Physical Geography'' (Oxford: Blackwell, 2000), 301. . Maars range in size from across and from deep. Most maars fill with water to form natural lakes. Most maars have low rims composed of a mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme. Etymology The name ''maar'' comes from a Moselle Franconian language, Moselle Franconian dialect word used for the circular lakes of the Daun (Germany), 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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatomagmatic Eruption
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts.Heiken, G. & Wohletz, K. 1985. Volcanic Ash. University of California Press, Berkeley It is common for a large explosive eruption to have magmatic and phreatomagmatic components. Mechanisms Several competing theories exist as to the exact mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water. In many cases the water is supplied by the sea, such as in the Surtsey eruption. In other cases the water may be present in a lake or caldera-lake, as at Santorini, where the phreatomagmatic component of the Minoan eruption was a result of both a lake and later the sea. There have also been examples of interaction between mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devil Mountain Lakes
Devil Mountain Lakes ( Inupiaq: ''Qitiqłiik'') is a maar (a form of crater lake) in the western part of Alaska. The lake is considered to be the largest maar in the world; , Alaska Science Forum it is part of the Espenberg volcanic field, Espenberg volcanic field. Geography Devil Mountain Lakes is located about southwest of Kotzebue on the northern part of the .[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eichholzmaar
The Eichholzmaar is one of the smaller maars in the Volcanic Eifel and lies on the ''Landstraße'' between Steffeln and Duppach. It has a diameter of c. 120 metres. Its greatest depth is 3 metres. The circular shape of the bowl of the maar can still be easily seen. It lies exactly on a geological fault line, which runs from northwest to southeast. At the beginning of the 20th century the maar was drained in order to create meadows. From late summer 2007 to spring 2008 a renaturalisation was carried out and the lake restored with an area of c. 1,1 hectares. In only a few years the maar has become a refuge for rare water birds and reptiles. Two natural mineral springs in the immediate vicinity of the maar are accessible on foot. About 300 metres upstream in a westerly direction from the Eichholzmaar is the mineral spring known as the ''Steffelner Dress'' (). Around 270 metres downstream in an easterly direction from the Eichholzmaar is the mineral spring of ''Aueler Dress'' (). D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eckfelder Maar
The Eckfelder Maar is a former volcanic lake, that was formed during the Middle Eocene around 44.3 million years ago and is thus the oldest known maar. It lies in the southwestern Eifel mountains near Manderscheid in Germany.''Das Eckfelder Maar'' at www.eckfelder-maar.de. Retrieved 22 Jul 2016. It is also an important site that contains numerous fossil remains of fauna and flora, some of them nearly complete state of preservation. It has been continuously scientifically researched since 1987. The large number of finds - to date 25,000 fossil specimens have been found - have enabled a very detailed reconstruction of the landscape. This |
Daun (Germany)
Daun () is a town in the Vulkaneifel district in Rhineland-Palatinate, Germany. It is the district seat and also the seat of the ' of Daun. Geography Location The town lies in the , a part of the Eifel known for its volcanic history, geographical and geological features, and even ongoing activity today, including gases that sometimes well up from the earth. Daun lies south of the High Eifel on the river Lieser. Found from 2.5 to 3.5 km southeast of Daun’s town centre are the Dauner ''Maare'', a group of three volcanic lakes separated almost wholly by only the walls of tuff between them. The town is home to the '. Daun is furthermore a spa town and has mineral water springs. Constituent communities The district seat of Daun has 8,514 inhabitants (as of 31 December 2005, counting only those with their main residence in the town). Besides the main town, also called Daun (4,264 inhabitants), the municipal area also includes these outlying centres (') that were form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cape Espenberg
Cape Espenberg is a cape located on the Seward Peninsula in Alaska, on the Chukchi Sea coast. Cape Espenberg points northwards, 42 mi NW of Deering, Kotzebue-Kobuk Low. On its southeastern side there is the small Goodhope Bay, an inlet of the Kotzebue Sound. Named in 1816 by Lt. Otto von Kotzebue (1821, p. 236) for Dr. Karl Espenberg, a surgeon who accompanied Captain (later Admiral, IRN) Adam Johann von Krusenstern Adam Johann von Krusenstern (; 10 October 177012 August 1846) was a Russian admiral and explorer of Swedish and Baltic German descent, who led the first Russian circumnavigation of the Earth in 1803–1806. Life Krusenstern was born i ... on his voyage around the world in 1803–06. Cape Espenberg lies on the Arctic Circle at the terminus of a 30 km long mainland attached beach ridge plain at the northern limit of Seward Peninsula, in western Alaska. At the entry of the shallow Kotzebue Sound embayment, Cape Espenberg faces a potent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seward Peninsula
The Seward Peninsula is a large peninsula on the western coast of the U.S. state of Alaska whose westernmost point is Cape Prince of Wales. The peninsula projects about into the Bering Sea between Norton Sound, the Bering Strait, the Chukchi Sea, and Kotzebue Sound, just below the Arctic Circle. The entire peninsula is about long and wide. Like Seward, Alaska, it was named after William H. Seward, the United States Secretary of State who fought for the U.S. purchase of Alaska. The Seward Peninsula is a remnant of the Bering land bridge, a roughly thousand-mile-wide swath of land connecting Siberia with mainland Alaska during the Pleistocene Ice Age. This land bridge aided in the migration of humans, as well as plant and animal species, from Asia to North America. Excavations at sites such as the Trail Creek Caves and Cape Espenberg in the Bering Land Bridge National Preserve as well as Cape Denbigh to the south have provided insight into the timeline of prehistorical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steffeln
Steffeln is an '' Ortsgemeinde'' – a municipality belonging to a ''Verbandsgemeinde'', a kind of collective municipality – in the Vulkaneifel district in Rhineland-Palatinate, Germany. It belongs to the ''Verbandsgemeinde'' of Gerolstein, whose seat is in the municipality of Gerolstein. Geography Location The municipality lies in the Vulkaneifel, a part of the Eifel known for its volcanic history, geographical and geological features, and even ongoing activity today, including gases that sometimes well up from the earth. Constituent communities Steffeln's ''Ortsteile'' are, besides the main centre, also called Steffeln, Auel and Lehnerath. Climate Yearly precipitation in Steffeln amounts to 946 mm, which is very high, falling into the highest fourth of the precipitation chart for all Germany. At 81% of the German Weather Service's weather stations, lower figures are recorded. The driest month is April. The most rainfall comes in December. In that month, precipi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CIRCULAR
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{{disambiguation ...
Circular may refer to: * The shape of a circle * ''Circular'' (album), a 2006 album by Spanish singer Vega * Circular letter (other), a document addressed to many destinations ** Government circular, a written statement of government policy **Circulaire * Circular reasoning, a type of logical fallacy * Circular reference *Circular Quay, Australia *Circular Park, Armenia See also * Circular DNA (other) * Circular Line (other) * Circularity (other) Circularity may refer to: *Circular definition *Circular economy *Circular reasoning Circular reasoning (, "circle in proving"; also known as circular logic) is a fallacy, logical fallacy in which the reasoner begins with what they are trying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggradation
Aggradation (or alluviation) is the term used in geology for the increase in land elevation, typically in a river system, due to the deposition of sediment. Aggradation occurs in areas in which the supply of sediment is greater than the amount of material that the system is able to transport. The mass balance between sediment being transported and sediment in the bed is described by the Exner equation. Typical aggradational environments include lowland alluvial rivers, river deltas, and alluvial fans. Aggradational environments are often undergoing slow subsidence which balances the increase in land surface elevation due to aggradation. After millions of years, an aggradational environment will become a sedimentary basin, which contains the deposited sediment, including paleochannels and ancient floodplains. Aggradation can be caused by changes in climate, land use, and geologic activity, such as volcanic eruption, earthquake An earthquakealso called a quake, tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
