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Keurusselkä
Keurusselkä is a lake in Central Finland between the towns of Keuruu to the north and Mänttä to the south. It covers an area of . Its average depth is with a maximum depth of . The surface lies at above sea level. The lake is long and is a part of the Kokemäenjoki, Kokemäenjoki River drainage basin, basin. Keurusselkä gained international publicity in 2004 when a pair of amateur geologists discovered an ancient impact structure on the western shore of the lake. Etymology Keurusselkä was originally only the name of the largest fjard of the lake, while the lake was known as ''Väärinkeuru'' or ''Keuruvesi''. The element ''keuru'' is a dialectal word meaning "crooked", in this context referring to the shape of the lake. The older names were displaced by the name Keurusselkä in the 19th century. The name of Keuruu is derived from the lake's name. Environmental issues In 1986, the Keurusselkä region was heavily contaminated (70 Becquerel, kBq/m2) by radioactive decay, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keuruu
Keuruu (; ) is a List of cities and towns in Finland, town and municipalities of Finland, municipality of Finland. It is located in the provinces of Finland, province of Western Finland and is part of the Central Finland regions of Finland, region. The municipality has a population of () and covers an area of of which is water. The population density is . The town center and Haapamäki village are both the most populated places in Keuruu. The municipality is unilingually Finnish language, Finnish. The municipality of Pihlajavesi, Keuruu, Pihlajavesi was consolidated with Keuruu in 1969. The subject of the coat of arms of Keuruu is inspired by agriculture (referenced by crossed Flail (tool), flails) and the church trips that were once made in the area on long rowboats. The coat of arms was designed by Olof Eriksson and was adopted on December 30, 1952. Geography Neighbouring municipalities are Jämsä, Multia, Mänttä-Vilppula, Petäjävesi, Virrat and Ähtäri. There are 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landsat 7
Landsat 7 is the seventh satellite of the Landsat program. Launched on 15 April 1999, Landsat 7's primary goal is to refresh the global archive of satellite photos, providing up-to-date and cloud-free images. The Landsat program is managed and operated by the United States Geological Survey, and data from Landsat 7 is collected and distributed by the USGS. The NASA WorldWind project allows 3D images from Landsat 7 and other sources to be freely navigated and viewed from any angle. The satellite's companion, Earth Observing-1, trailed by one minute and followed the same orbital characteristics, but in 2011 its fuel was depleted and EO-1's orbit began to degrade. Landsat 7 was built by Lockheed Martin Space Systems. In 2016, NASA announced it planned to attempt the first ever refueling of a live satellite by refueling Landsat 7 in 2020 with the OSAM-1 mission. However after multiple delays, NASA announced the cancellation of OSAM-1 in March 2024. The mission officially ended in 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Plant
A nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a electric generator, generator that produces electricity. , the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction. Most nuclear power plants use thermal reactors with enriched uranium in a Nuclear fuel cycle#Once-through nuclear fuel cycle, once-through fuel cycle. Fuel is removed when the percentage of neutron poison, neutron absorbing atoms becomes so large that a nuclear chain reaction, chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planar Deformation Features
Planar deformation features, or PDFs, are optically recognizable microscopic features in grains of silicate minerals (usually quartz or feldspar), consisting of very narrow planes of glassy material arranged in parallel sets that have distinct orientations with respect to the grain's crystal structure. PDFs are only produced by extreme shock compressions on the scale of meteor impacts. They are not found in volcanic environments. Their presence therefore is a primary criterion for recognizing that an impact event has occurred. See also * Shocked quartz * Shock metamorphism Shock metamorphism or impact metamorphism describes the effects of shock-wave related deformation and heating during impact events. The formation of similar features during explosive volcanism is generally discounted due to the lack of metamorp ... References * http://www.lpi.usra.edu/publications/slidesets/craters/glossary.shtml * https://www.unb.ca/passc/ImpactDatabase/essay.html * Impact geology M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a Fracture (geology), planar fracture or discontinuity in a volume of Rock (geology), rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust (geology), crust result from the action of Plate tectonics, plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction, subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the Plane (geometry), plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geological maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Metamorphism
Shock metamorphism or impact metamorphism describes the effects of shock-wave related deformation and heating during impact events. The formation of similar features during explosive volcanism is generally discounted due to the lack of metamorphic effects unequivocally associated with explosions and the difficulty in reaching sufficient pressures during such an event. Effects Mineral microstructures Planar fractures Planar fractures are parallel sets of multiple planar cracks or cleavages in quartz grains; they develop at the lowest pressures characteristic of shock waves (~5–8 GPa) and a common feature of quartz grains found associated with impact structures. Although the occurrence of planar fractures is relatively common in other deformed rocks, the development of intense, widespread, and closely spaced planar fractures is considered diagnostic of shock metamorphism. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breccia
Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, fault (geology), fault or tectonics, tectonic breccia, igneous breccia, Impact event, impact breccia, and Hydrothermal circulation, hydrothermal breccia. A megabreccia is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides, impact events, or caldera collapse. Types Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like Conglomerate (geology), conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from Conglomerate (geol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Lappajärvi
Lappajärvi is a lake in Finland, in the municipalities of Finland, municipalities of Lappajärvi, Alajärvi and Vimpeli. It is formed in a wide, partly eroded meteorite impact crater. The lake is part of Ähtävänjoki () basin together with Lake Evijärvi that is located downstream (north) of it. The Lappajärvi impact structure is estimated to be 77.85 ± 0.78 million years old (Campanian age of the Late Cretaceous time period). Experts working on Finland's Onkalo spent nuclear fuel repository project have studied Lake Lappajärvi to help them project how Finnish landscapes might look one million years in the future and beyond. An island in the middle of the lake, Kärnänsaari (Kärnä Island), gives the name to the black impact melt rock (impactite) found there, locally called ''Kärnäiitti''. Nearby towns include Lappajärvi and Vimpeli and the nearest major city is Seinäjoki. In September 2023, UNESCO accepted the Lappajärvi area's "Impact Crater Lake" Geopark applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shatter Cone
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the range of . Morphology Shatter cones have a distinctively conical shape that radiates from the top (''apex'') of the cones repeating cone-on-cone in large and small scales in the same sample. Sometimes they have more of a spoon shape on the side of a larger cone. In finer-grained rocks such as limestone, they form an easily recognizable "horsetail" pattern with thin grooves ('' striae''). Coarser grained rocks tend to yield less well developed shatter cones, which may be difficult to distinguish from other geological formations such as slickensides. Geologists have various theories of what causes shatter cones to form, including compression by the wave as it passes through the rock or tension as the rocks rebound after the pressure subsides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologist
A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, field and the laboratory. Geologists work in the Energy industry, energy and mining sectors to exploit Natural resource, natural resources. They monitor environmental hazards such as earthquakes, volcanoes, tsunamis and landslides. Geologists are also important contributors to climate change discussions. History James Hutton is often viewed as the first modern geologist. In 1785 he presented a paper entitled ''Theory of the Earth'' to the Royal Society of Edinburgh. In his paper, he explained his theory that the Earth must be much older than had previously been supposed to allow enough time for mountains to be eroded and for sediments to form new rocks at the bottom of the sea, which in turn were raised up to become dry land. Hutton pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Perch
The European perch (''Perca fluviatilis''), also known as the common perch, redfin perch, big-scaled redfin, English perch, Euro perch, Eurasian perch, Eurasian river perch, Hatch, poor man's rockfish or in Anglophone parts of Europe, simply the perch, is a predatory freshwater fish native to Europe and North Asia. It is the type species of the genus '' Perca''. The perch is a popular game fish for recreational anglers, and has been widely introduced beyond its native Eurasian habitats into Australia, New Zealand and South Africa. Known locally simply as "redfin", they have caused substantial damage to native fish populations in Australia and have been proclaimed a noxious species in New South Wales. Taxonomy The first scientific description of the river perch was made by Peter Artedi in 1730. He defined the basic morphological signs of this species after studying perch from Swedish lakes. Artedi described its features, counting the fin rays scales and vertebrae of the typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Pike
The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are known simply as a pike (Plural, : pike) in Great Britain, Ireland, most of Eastern Europe, Canada and the United States, U.S., although in the Midwestern United States, they may just be called a Northern. Pike can grow to a relatively large size. Their average length is about , with maximum recorded lengths of up to and maximum weights of . The International Game Fish Association, IGFA currently recognises a pike caught by Lothar Louis on Greffern Lake, Germany, on 16 October 1986, as the all-tackle world-record holding northern pike. Northern pike grow to larger sizes in Eurasia than in North America, and in coastal Eurasian regions than inland ones. Etymology The northern pike gets its common name from its resemblance to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
