In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with larger body. In most common usage, the term is used for the approximately circular depression in the surface of a planet, moon or other solid body in the Solar System, formed by the hyper-velocity impact of a smaller body with the surface. Depression in Geology is a Landform sunken or depressed below the surrounding area A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is A natural satellite or moon is a Celestial body that Orbits a Planet or smaller body which is called the primary. The Solar System consists of the Sun and those celestial objects bound to it by Gravity. The term hypervelocity usually refers to a very high Velocity, typically over 3000 meters per second (6700 mph 11000 km/h 10000 ft/s or Mach A collision is an isolated event in which two or more bodies (colliding bodies exert relatively strong forces on each other for a relatively short time This is in contrast to the pit crater which results from an internal collapse. A pit crater (also called a subsidence crater) is a depression formed by a sinking of the ground surface lying above a void or empty chamber rather than by Impact craters typically have raised rims, and they range from small, simple, bowl-shaped depressions to large, complex, multi-ringed, impact basins. Meteor Crater or pit crater is perhaps the best-known example of a small impact crater on the Earth. Meteor Crater is a Meteorite Impact crater located approximately 43 miles east of Flagstaff, near Winslow in the northern A pit crater (also called a subsidence crater) is a depression formed by a sinking of the ground surface lying above a void or empty chamber rather than by
Impact craters provide the dominant landforms on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. TemplateInfobox Planet.--> Callisto (kəˈlɪstoʊ, or as Greek TemplateInfobox Planet.--> Ganymede (ˈgænɨmiːd, or as Greek Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but On other planets and moons that experience more-active surface geological processes, such as Earth, Venus, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University TemplateInfobox Planet.--> Europa (jʊˈroʊpə; or as TemplateInfobox Planet.--> Io (ˈaɪoʊ, or as Greek TemplateInfobox Planet.--> Titan (ˈtaɪtən, or as Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind This article discusses the geologic usage for the philosophical or architectural usage see Architectonics ' Or see Plate tectonics. Where such processes have destroyed most of the original crater topography, the terms impact structure or astrobleme are more commonly used. The term impact structure is closely related to the terms Impact crater or Meteorite Impact crater, and is used in cases where erosion or burial have destroyed In early literature, before the significance of impact cratering was widely recognised, the terms cryptoexplosion or cryptovolcanic structure were often used to describe what are now recognised as impact-related features on Earth. The term cryptoexplosion structure (or cryptovolcanic structure is now largely obsolete but was once commonly used to describe sites where there was geological evidence of
In the early Solar System, rates of impact cratering were much higher than today. The large multi-ringed impact basins, with diameters of hundreds of kilometres or more, retained for example on Mercury and the Moon, record a period of intense early bombardment in the inner Solar System that ended about 3. The Late Heavy Bombardment (commonly referred to as the lunar cataclysm, or LHB) is a period of time approximately 3800 to 4100 million years ago ( mya 8 billion years ago. Since that time, the rate of crater production on Earth has been considerably lower, but it is appreciable nonetheless; Earth experiences from one to three impacts large enough to produce a 20 km diameter crater about once every million years on average. This indicates that there should be far more relatively young craters on the planet than have been discovered so far.
Although the Earth’s active surface processes quickly destroy the impact record, about 170 terrestrial impact craters have been identified. These range in diameter from a few tens of meters up to about 300 km, and they range in age from recent times (e. g. the Sikhote-Alin craters in Russia witnessed in 1947) to more than two billion years, though most are less than 200 million years old because geological processes tend to obliterate older craters. Sikhote-Alin is an iron Meteorite fell in 1947 on the Sikhote-Alin Mountains in ( Russia) Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending They are also selectively found in the stable interior regions of continents. A craton ( Greek kratos / κρἀτος ( neut. "strength" is an old and stable part of the Continental crust that has survived Few under sea craters have been discovered because of the difficulty of surveying the sea floor, the rapid rate of change of the ocean bottom, and the subduction of the ocean floor into the Earth's interior by processes of plate tectonics. In Geology, a subduction zone is an area on Earth where two tectonic plates meet and move towards one another with one sliding underneath the other Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere
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History
Daniel Barringer (1860-1929) was one of the first to identify an impact crater, Meteor Crater in Arizona; to crater specialists the site is referred to as Barringer Crater in his honor. For other persons named Daniel Barringer see Daniel Barringer. Meteor Crater is a Meteorite Impact crater located approximately 43 miles east of Flagstaff, near Winslow in the northern The State of Arizona ( is a state located in the southwestern region of the United States. Meteor Crater is a Meteorite Impact crater located approximately 43 miles east of Flagstaff, near Winslow in the northern Initially Barringer's ideas were not widely accepted, and even when the origin of Meteor Crater was finally acknowledged, the wider implications for impact cratering as a significant geological process on Earth were not.
In the 1920s, the American geologist Walter H. Bucher studied a number of sites now recognized as impact craters in the USA. Dr Walter Hermann Bucher (March 12 1889&ndashFebruary 17 1965 was a German - American Geologist and Paleontologist. He concluded they had been created by some great explosive event, but believed that this force was probably volcanic in origin. Plate tectonics and hotspots Divergent plate boundaries At the However, in 1936, the geologists John D. Boon and Claude C. Albritton Jr. revisited Bucher's studies and concluded that the craters that he studied were probably formed by impacts.
The concept of impact cratering remained more or less speculative until the 1960s. At this time a number of researchers, most notably Eugene M. Shoemaker, conducted detailed studies of a number of craters and recognized clear evidence that they had been created by impacts, specifically identifying the shock-metamorphic effects uniquely associated with impact events, of which the most familiar is shocked quartz. Eugene Merle Shoemaker (or Gene Shoemaker ( April 28, 1928 &ndash July 18, 1997) was one of the founders of the fields of Planetary Shocked quartz is a form of Quartz that has a microscopic structure that is different from normal quartz
Armed with the knowledge of shock-metamorphic features, Carlyle S. Beals and colleagues at the Dominion Observatory in Victoria, British Columbia, Canada, and Wolf von Engelhardt of the University of Tübingen in Germany began a methodical search for impact craters. The Dominion Observatory was an astronomical Observatory in Ottawa, Canada that operated from 1902 to 1970 Victoria (vɪkˈtɔɹiə is the capital city of British Columbia. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Eberhard Karls University of Tübingen ( German: Eberhard Karls Universität Tübingen, sometimes called the "Eberhardina Carolina" is a public university Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. By 1970, they had tentatively identified more than 50. Although their work was controversial, the American Apollo Moon landings, which were in progress at the time, provided supportive evidence by recognizing the rate of impact cratering on the Moon. Processes of erosion on the Moon are minimal and so craters persist almost indefinitely. Since the Earth could be expected to have roughly the same cratering rate as the Moon, it became clear that the Earth had suffered far more impacts than could be seen by counting evident craters.
Crater formation
Impact cratering involves high velocity collisions between solid objects, typically much greater than the velocity of sound in those objects. Sound is a vibration that travels through an elastic medium as a Wave. Such hyper-velocity impacts produce physical effects such as melting and vaporization, that do not occur in familiar sub-sonic collisions. Melting is a process that results in the phase change of a substance from a Solid to a Liquid. Evaporation is the process by which Molecules in a Liquid state (e On Earth, ignoring the slowing effects of travel through the atmosphere, the lowest impact velocity with an object from space is equal to the gravitational escape velocity of about 11 km/s. In Physics, escape velocity is the speed where the Kinetic energy of an object is equal to the magnitude of its Gravitational potential energy The fastest impacts occur at more than 70 km/s, calculated by summing the escape velocity from Earth, the escape velocity from the Sun at the Earth's orbit, and the motion of the Earth around the Sun. In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star The median impact velocity on Earth is about 20 to 25 km/s. In Probability theory and Statistics, a median is described as the number separating the higher half of a sample a population or a Probability distribution
Impacts at these high speeds produce shockwaves in solid materials, and both impactor and the material impacted are rapidly compressed to high density. For the music album by Converter see Shock Front For the 1977 horror film see Shock Waves A shock wave (also called Physical compression is the result of the subjection of a material to Compressive stress, resulting in reduction of Volume. Following initial compression, the high-density, over-compressed region rapidly depressurizes, exploding violently, to set in train the sequence of events that produces the impact crater. Impact-crater formation is therefore more closely analogous to cratering by high explosives than by mechanical displacement. An explosive material is a material that either is chemically or otherwise Energetically unstable or produces a sudden expansion of the material usually accompanied Indeed, the energy density of some material involved in the formation of impact craters is many times higher than that generated by high explosives. Energy density is the amount of Energy stored in a given system or region of space per unit Volume, or per unit Mass, depending on the context although Since craters are caused by explosions, they are nearly always circular – only very low-angle impacts cause significantly elliptical craters. An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release
It is convenient to divide the impact process conceptually into three distinct stages: (1) initial contact and compression, (2) excavation, (3) modification and collapse. In practice, there is overlap between the three processes with, for example, the excavation of the crater continuing in some regions while modification and collapse is already underway in others.
Contact and compression
In the absence of atmosphere, the impact process begins when the impactor first touches the target surface. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " This contact accelerates the target and decelerates the impactor. Because the impactor is moving so rapidly, the rear of the object moves a significant distance during the short-but-finite time taken for the deceleration to propagate across the impactor. As a result, the impactor is compressed, its density rises, and the pressure within it increases dramatically. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Peak pressures in large impacts exceed 1 TPa to reach values more usually found deep in the interiors of planets, or generated artificially in nuclear explosions. TERA is a shielded Twisted pair connector for use with Category 7 twisted-pair data cables developed by The Siemon Company and standardized in 2003 by The energy released from a nuclear weapon detonated in the Troposphere can be divided into four basic categories Blast &mdash40-50% of total energy
In physical terms, a supersonic shockwave initiates from the point of contact. For other uses see Supersonic. The term supersonic is used to define a speed that is over the Speed of sound ( Mach 1 As this shockwave expands, it decelerates and compresses the impactor, and it accelerates and compresses the target. Stress levels within the shockwave far exceeds the strength of solid materials; consequently, both the impactor and the target close to the impact site are irreversibly damaged. Many crystalline minerals can be transformed into higher-density phases by shockwaves, for example the common mineral quartz can be transformed into the higher-pressure forms coesite and stishovite. Coesite is a form ( polymorph) of Silicon dioxide Si[[oxygen O]]2 that is formed when very high pressure (2&ndash3 Gigapascals and Stishovite (after SM Stishov 20th-century Russian mineralogist is an extremely hard dense Tetragonal form ( polymorph) of Silicon dioxide. Many other shock-related changes take place within both impactor and target as the shockwave passes through, and some of these changes can be used as diagnostic tools to determine whether particular geological features were produced by impact cratering.
As the shockwave decays, the shocked region decompresses towards more usual pressures and densities. The damage produced by the shockwave raises the temperature of the material, and in all but the smallest impacts this increase in temperature is sufficient to melt the impactor, and in larger impacts to vaporize most of it and to melt large volumes of the target. As well as being heated, the target near the impact is accelerated by the shockwave, and it remains moving away from the impact behind the decaying shockwave.
Excavation
Contact, compression, decompression, and the passage of the shockwave all occur within a few tenths of a second for a large impact. The subsequent excavation of the crater occurs more slowly, and during this stage the flow of material is largely sub-sonic. During excavation, the crater grows as the accelerated target moves away from the impact point. The motion is initially downwards and outwards, and with time this evolves to becomes outwards and upwards. The flow initially produces an approximately hemispherical cavity. The cavity continues to grow, eventually producing a paraboloid (bowl-shaped) crater in which the centre has been pushed down, a significant volume of material has been ejected, and a topographically elevated crater rim has been pushed up. When this cavity has reached its maximum size, it is called the transient cavity.
The depth of the transient cavity is typically a quarter to a third of its diameter. Herschel (ˈhɝːʃəl is a huge crater on the Saturnian moon Mimas. TemplateInfobox Planet. --> Mimas (ˈmaɪməs, or as Greek Ejecta thrown out of the crater does not include material excavated from the full depth of the transient cavity - typically the depth of maximum excavation is only about a third of the total depth. As a result, about one third of the volume of the transient crater is formed by the ejection of material, and the remaining two thirds is formed by the displacement of material downwards, outwards and upwards, to form the elevated rim. For impacts into highly porous materials, a significant crater volume may also be formed by the permanent compaction of the pore space. Such compaction craters may be important on many asteroids, comets and small moons.
In large impacts, as well as material displaced and ejected to form the crater, significant volumes of target material may be melted and vaporized together with the original impactor. Some of this impact melt rock may be ejected, but most of it remains within the transient crater, initially forming a layer of impact melt coating the interior of the transient cavity. In contrast, the hot dense vaporized material expands rapidly out of the growing cavity, carrying some solid and molten material within it as it does so. As this hot vapor cloud expands, it rises and cools much like the archetypal mushroom cloud generated by large nuclear explosions. In large impacts, the expanding vapor cloud may rise to many times the scale height of the atmosphere, effectively expanding into free space.
Most material ejected from the crater is deposited within a few crater radii, but a small fraction may travel large distances at high velocity, and in large impacts it may exceed escape velocity and leave the impacted planet or moon entirely. In Physics, escape velocity is the speed where the Kinetic energy of an object is equal to the magnitude of its Gravitational potential energy The majority of the fastest material is ejected from close to the centre of impact, and the slowest material is ejected close to the rim at low velocities to form an overturned coherent flap of ejecta immediately outside the rim. As ejecta escapes from the growing crater, it forms an expanding curtain in the shape of an inverted cone; the trajectory of individual particles within the curtain is thought to be largely ballistic.
Small volumes of un-melted and relatively un-shocked material may be spalled at very high relative velocities from the surface of the target and from the rear of the impactor. Spall are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms including as a result of Projectile impact Corrosion Spalling provides a potential mechanism whereby material may be ejected into inter-planetary space largely undamaged, and whereby small volumes of the impactor may be preserved undamaged even in large impacts. Small volumes of high-speed material may also be generated early in the impact by jetting. This occurs when two surfaces converge rapidly and obliquely at a small angle, and high-temperature highly shocked material is expelled from the convergence zone with velocities that may be several times larger than the impact velocity.
Modification and collapse
In most circumstances, the transient cavity is not stable: it collapses under gravity. In small craters, less than about 4 km diameter on Earth, there is some limited collapse of the crater rim coupled with debris sliding down the crater walls and drainage of impact melts into the deeper cavity. The resultant structure is called a simple crater, and it remains bowl-shaped and superficially similar to the transient crater. In simple craters, the original excavation cavity is overlain by a lens of collapse breccia, ejecta and melt rock, and a portion of the central crater floor may sometimes be flat. Breccia (ˈbrɛtʃiə ˈbrɛʃiə breach is a rock composed of angular fragments of several Minerals or rocks in a matrix, that is a cementing material
Above a certain threshold size, which varies with planetary gravity, the collapse and modification of the transient cavity is much more extensive, and the resulting structure is called a complex crater. TemplateInfobox Planet.--> Callisto (kəˈlɪstoʊ, or as Greek The collapse of the transient cavity is driven by gravity, and involves both the uplift of the central region and the inward collapse of the rim. The central uplift is not the result of elastic rebound which is a process in which a material with elastic strength attempts to return to its original geometry; rather the collapse is a process in which a material with little or no strength attempts to return to a state of gravitational equilibrium.
Complex craters have uplifted centers, and they have typically broad flat shallow crater floors, and terraced walls. At the largest sizes, one or more exterior or interior rings may appear, and the structure may be labeled an impact basin rather than an impact crater. Complex-crater morphology on rocky planets appears to follow a regular sequence with increasing size: small complex craters with a central topographic peak are called central peak craters, for example Tycho; intermediate-sized craters, in which the central peak is replaced by a ring of peaks, are called peak-ring craters, for example Schrodinger; and the largest craters contain multiple concentric topographic rings, and are called multi-ringed basins, for example Orientale. Tycho is a prominent lunar Impact crater located in the southern lunar highlands named after the Danish Astronomer Tycho Brahe. Schrödinger is a huge lunar Impact crater of the form normally called a walled-plain Like a target ring bull's-eye the Lunar mare Mare Orientale (the "eastern sea" is one of the most striking large scale lunar features On icy as opposed to rocky bodies, other morphological forms appear which may have central pits rather than central peaks, and at the largest sizes may contain very many concentric rings – Valhalla on Callisto is the type example of the latter. Valhalla is the largest multi-ring structure Impact crater on Jupiter 's moon Callisto.
Identifying impact craters
Some volcanic features can resemble impact craters, and brecciated rocks are associated with other geological formations besides impact craters. Breccia (ˈbrɛtʃiə ˈbrɛʃiə breach is a rock composed of angular fragments of several Minerals or rocks in a matrix, that is a cementing material Clastic rocks are composed of fragments or clasts, of pre-existing rock. Non-explosive volcanic craters can usually be distinguished from impact craters by their irregular shape and the association of volcanic flows and other volcanic materials. An exception is that impact craters on Venus often have associated flows of melted material.
The distinctive mark of an impact crater is the presence of rock that has undergone shock-metamorphic effects, such as shatter cones, melted rocks, and crystal deformations. Shatter cones are rare geological features that are only known to form in the bedrock beneath Meteorite impact craters or underground nuclear explosions The problem is that these materials tend to be deeply buried, at least for simple craters. They tend to be revealed in the uplifted center of a complex crater, however.
Impacts produce distinctive "shock-metamorphic" effects that allow impact sites to be distinctively identified. Breccia (ˈbrɛtʃiə ˈbrɛʃiə breach is a rock composed of angular fragments of several Minerals or rocks in a matrix, that is a cementing material The 35-40 km-diameter Azuara Impact crater is located in northeast Spain roughly 50 km south of Zaragoza. Such shock-metamorphic effects can include:
- A layer of shattered or "brecciated" rock under the floor of the crater. Breccia (ˈbrɛtʃiə ˈbrɛʃiə breach is a rock composed of angular fragments of several Minerals or rocks in a matrix, that is a cementing material This layer is called a "breccia lens".
- Shatter cones, which are chevron-shaped impressions in rocks. Such cones are formed most easily in fine-grained rocks.
- High-temperature rock types, including laminated and welded blocks of sand, spherulites and tektites, or glassy spatters of molten rock. Spherulites, in Petrology, are small rounded bodies that commonly occur in Vitreous Igneous rocks They are often visible in specimens of Obsidian Tektites (from Greek tektos, molten are natural Glass objects up to a few centimeters in size which most scientists argue were formed by the impact of The impact origin of tektites has been questioned by some researchers; they have observed some volcanic features in tektites not found in impactites. Tektites are also drier (contain less water) than typical impactites. While rocks melted by the impact resemble volcanic rocks, they incorporate unmelted fragments of bedrock, form unusually large and unbroken fields, and have a much more mixed chemical composition than volcanic materials spewed up from within the Earth. They also may have relatively large amounts of trace elements that are associated with meteorites, such as nickel, platinum, iridium, and cobalt. Note: it is reported in the scientific literature that some "shock" features, such as small shatter cones, which are often reported as being associated only with impact events, have been found in terrestrial volcanic ejecta.
- Microscopic pressure deformations of minerals. These include fracture patterns in crystals of quartz and feldspar, and formation of high-pressure materials such as diamond, derived from graphite and other carbon compounds, or stishovite and coesite, varieties of shocked quartz. Coesite is a form ( polymorph) of Silicon dioxide Si[[oxygen O]]2 that is formed when very high pressure (2&ndash3 Gigapascals and Shocked quartz is a form of Quartz that has a microscopic structure that is different from normal quartz
Craters can also be created from underground nuclear explosions. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. One of the most crater-pocked sites on the planet is the Nevada Test Site, where a number of craters were purposely made during its years as a center for nuclear testing (see, for example, Operation Plowshare). The Nevada Test Site is a United States Department of Energy reservation located in Nye County, Nevada, about 65 miles (105 km northwest of the City of Nuclear weapons tests are experiments carried out to determine the effectiveness yield and explosive capability of Nuclear weapons Throughout the twentieth century most nations Operation Plowshare, better known as Project Plowshare not to be confused with the anti-nuclear Plowshares Movement, was the overall United States term for the development of
Lunar crater categorization
In 1978, Chuck Wood and Leif Andersson of the Lunar & Planetary Lab devised a system of categorization of lunar impact craters. They used a sampling of craters that were relatively unmodified by subsequent impacts, then grouped the results into five broad categories. These successfully accounted for about 99% of all lunar impact craters.
The LPC Crater Types were as follows:
- ALC — small, cup-shaped craters with a diameter of about 10 km or less, and no central floor. The archetype for this category is 'Albategnius C'. An archetype ( pronounced: /ˈɑːkɪtaɪp/ (Brit or /ˈɑrkɪtaɪp/ (Amer Albategnius is an ancient lunar Impact crater located in the central highlands
- BIO — similar to an ALC, but with small, flat floors. Typical diameter is about 15 km. The lunar crater archetype is Biot. Biot is a small bowl-shaped lunar crater located in the southern reaches of the Mare Fecunditatis.
- SOS — the interior floor is wide and flat, with no central peak. The inner walls are not terraced. The diameter is normally in the range of 15-25 km. The archetype is Sosigenes crater. Sosigenes is a lunar Impact crater on the west edge of Mare Tranquillitatis.
- TRI — these complex craters are large enough so that their inner walls have slumped to the floor. They can range in size from 15-50 km in diameter. The archetype crater is Triesnecker. Triesnecker is a prominent lunar Impact crater that is located in the Sinus Medii, near the central part of the Moon 's near side
- TYC — these are larger than 50 km, with terraced inner walls and relatively flat floors. They frequently have large central peak formations. Tycho crater is the archetype for this class. Tycho is a prominent lunar Impact crater located in the southern lunar highlands named after the Danish Astronomer Tycho Brahe.
Beyond a couple of hundred kilometers diameter, the central peak of the TYC class disappear and they are classed as basins.
Lists of craters
Notable impact craters on Earth
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See the Earth Impact Database,[1] a website concerned with over 170 identified impact craters on the Earth. This list of Impact craters on Earth includes all confirmed impact craters as listed in the Earth Impact Database. This is a list of named craters on Mercury. All Mercurian Craters are named after famous Writers and Artists Craters larger than 250km in diameter This is a list of craters on the Moon. The large majority of these features are Impact craters The crater nomenclature is governed by the International There are hundreds of thousands of craters on Mars, but only some of them have names In addition to the large Galilean moons, Jupiter is orbited by sixty three smaller moons but only two of them Amalthea and Thebe, have been imaged at sufficient The surface of Jupiter 's moon Europa, is very young geologically speaking and as a result there are very few craters Furthermore as Europa's surface is potentially Ganymede is the largest moon in the Solar system, and thus has many craters covering its hard surface Callisto, one of the many moons of Jupiter, is the most heavily cratered moon in the Solar system. This is list of named geological features on Janus, Epimetheus and Phoebe. This is a list of named geological features on Mimas. The geological features of Mimas are named after people and places in Arthurian legend or the legends of the This is a list of named geological features on Enceladus. Geological features on Enceladus are named after people and places from the Arabian Nights, a This is a list of named geological features on Tethys. Tethysian geological features are named after people and places in The Iliad and The Odyssey This is a list of named geological features on Dione. Dionean geological features are named after people and places in Roman mythology. This is a list of named geological features on Rhea, the second largest moon of Saturn. This is a list of named geological features on Iapetus. Most Iapetian geological features are named after characters and locations in the Chanson de Roland This is a list of named craters on Puck. Puckian craters are named after mischievous spirits in European Mythology. This is a list of named geological features on Miranda. Craters Mirandan craters are named after characters in Shakespeare 's This list of geological features on Ariel itemizes the named geological features on the Moon of Uranus called Ariel. This is a list of named craters on Umbriel. Umbrielian craters are named after evil spirits in various mythologies This is a list of named geological features on Titania. Chasms Titanian Chasms are called chasmata. This is a list of named geological features (mostly craters) on Oberon. This is a list of named geological features of various kinds on Triton, the Planet Neptune 's largest moon. This list of Impact craters on Earth includes all confirmed impact craters as listed in the Earth Impact Database. Meteor Crater is a Meteorite Impact crater located approximately 43 miles east of Flagstaff, near Winslow in the northern Beyenchime-Salaatin is an impact crater ( Astrobleme) at 71° 0' N 121° 40' E in the Russian Far East. Lake Bosumtwi, situated within an ancient Meteorite Impact crater, is approximately 8 km across and the only natural lake in Ghana. The Chesapeake Bay impact crater was formed by a Bolide that impacted the eastern shore of North America about 35 The Chicxulub Crater (tʃikʃuˈlub is an ancient Impact crater buried underneath the Yucatán Peninsula in Mexico. The Clearwater Lakes (officially known by the French name Lac à l'Eau Claire; the Cree call them Wiyasakami and the Inuit Connolly Basin is a 9 km-diameter circular depression interpreted as an eroded Meteorite Impact crater, located in the Gibson Desert of central Western Deep Bay is a bay near the south-western tip of Reindeer Lake in Saskatchewan, Canada. Gosses Bluff (Gosse's Bluff is an Impact crater in the southern Northern Territory, near the centre of Australia, about 175 km (109 Haughton Impact crater is located on Devon Island, Nunavut in far northern Canada. Kaali is a small group of 9 Meteorite craters on Saaremaa, Estonia. Kara-Kul or Qarokul (Қарoкул is a 25-kilometer (16-mile diameter Lake in the Pamir Mountains in Tajikistan, which lies at an Kebira Crater ( Arabic: فوهة كبيرة is the name that has recently been proposed for a circular topographic feature in the Sahara desert Lonar crater is an Impact crater situated in the Buldhana district of the Indian state of Maharashtra. Mahuika crater is a disputed submarine Bolide Impact crater, 20 ± 2 kilometers wide and over 153 meters deep on the New Zealand continental shelf at, Manicouagan Reservoir (also Lake Manicouagan) is an annular lake in central Quebec, Canada. See also Iowa geology The Manson Impact crater is near the site of Manson Iowa where an asteroid or comet nucleus struck the Earth during the Mistastin crater is a Meteorite crater in Labrador, Canada which contains the roughly circular Mistastin Lake. Morokweng crater (or Morokweng impact structure) is a large Meteorite crater buried beneath the Kalahari Desert near the town of Morokweng Ries Crater Rimjpg|thumb|right|250px|The crater rim near the village of Mönchsdeggingen There is also a Panther Mountain in Franklin County New York near the southern end of Lower Saranac Lake. The Popigai crater in Siberia, Russia is tied with Manicouagan Reservoir as the 4th largest Impact crater on Earth. The Río Cuarto craters are a group of depressions located in Córdoba Province, Argentina. Rochechouart is an impact crater in France. The crater Diameter is still under debate but expected to be about and its current age estimate Roter Kamm is a Meteorite crater, located within the Namibian section of the Namib Desert. Shoemaker (formerly known as Teague Ring) is an Impact structure (or Astrobleme) the deeply eroded remnant of a former Impact crater, situated Shunak is a Meteorite Impact crater located in the south-eastern part of Qaraghandy Province in Kazakhstan (No Siljan, in Dalarna in central Sweden, is Sweden's sixth largest Lake. Silverpit crater is a buried sub-sea structure under the North Sea off the coast of the United Kingdom The Sudbury Basin, also known as Sudbury Structure or the Sudbury Nickel Irruptive, is the second largest known Impact crater or Astrobleme Vredefort crater is the largest verified Impact crater on Earth. The Weaubleau-Osceola structure is thought to be a Meteorite impact site in western Missouri near the towns Wilkes Land crater is an informal term that may apply to two separate cases of conjectured giant Impact craters hidden beneath the Ice cap of Wilkes Land Yarrabubba crater refers to an Impact structure (or Astrobleme) the eroded remnant of a former Impact crater, situated in the northern Yilgarn Craton The Earth Impact Database is the authoritative source for information on confirmed impact structures or craters on Earth.
Some extraterrestrial craters
- Caloris Basin (Mercury)
- Hellas Basin (Mars)
- Mare Orientale (Moon)
- Petrarch crater (Mercury)
- Skinakas Basin (Mercury)
- South Pole-Aitken basin (Moon)
- Herschel crater (Mimas)
Largest named craters in the Solar System
- South Pole-Aitken basin - Moon - Diameter: 2,500 km
- Hellas Basin - Mars - Diameter: 2,100 km
- "Skinakas Basin" - Mercury - Diameter: ~1,600 km
- Caloris Basin - Mercury - Diameter: 1,550 km
- Mare Imbrium - Moon - Diameter: 1,100 km
- Isidis Planitia - Mars - Diameter: 1,100 km
- Mare Tranquilitatis - Moon - Diameter: 870 km
- Argyre Planitia - Mars - Diameter: 800 km
- Mare Serenitatis - Moon - Diameter: 700 km
- Mare Nubium - Moon - Diameter: 700 km
- Beethoven - Mercury - Diameter: 625 km
- Valhalla - Callisto - Diameter: 600 km, with rings to 4,000 km diameter
- Hertzsprung - Moon - Diameter: 590 km
- Apollo - Moon - Diameter: 540 km
- Huygens - Mars - Diameter: 470 km
- Schiaparelli - Mars - Diameter: 470 km
- Menrva - Titan - Diameter: 440 km
- Korolev - Moon - Diameter: 430 km
- Dostievskij - Mercury - Diameter: 400 km
- Odysseus - Tethys - Diameter: 400 km
- Tolstoj - Mercury - Diameter: 390 km
- Goethe - Mercury - Diameter: 380 km
- Mare Orientale - Moon - Diameter: 350 km, with rings to 930 km diameter
- Epigeus - Ganymede - Diameter: 340 km
- Gertrude - Titania - Diameter: 320 km
- Asgard - Callisto - Diameter: 300 km, with rings to 1,400 km diameter
- Vredefort crater - Earth - Diameter: 300 km
- Mead - Venus - Diameter: 270 km
There are approximately twelve more impact craters/basins larger than 300 km on the Moon, five on Mercury, and four on Mars. The Caloris Basin, also called Caloris Planitia, is an Impact crater on Mercury about 1550 km in Diameter, one of the largest False color of Hellas Planitiajpeg|thumb|220px|This elevation map shows the surrounding elevated debris ring]] Hellas Planitia, also known as the Hellas Impact Basin Like a target ring bull's-eye the Lunar mare Mare Orientale (the "eastern sea" is one of the most striking large scale lunar features This is a list of named craters on Mercury. All Mercurian Craters are named after famous Writers and Artists Craters larger than 250km in diameter The Skinakas Basin is the informal name given to a structure on Mercury that appears to be an extremely large Impact basin. The South Pole-Aitken basin is an Impact crater on Earth 's Moon. Herschel (ˈhɝːʃəl is a huge crater on the Saturnian moon Mimas. The South Pole-Aitken basin is an Impact crater on Earth 's Moon. False color of Hellas Planitiajpeg|thumb|220px|This elevation map shows the surrounding elevated debris ring]] Hellas Planitia, also known as the Hellas Impact Basin The Skinakas Basin is the informal name given to a structure on Mercury that appears to be an extremely large Impact basin. The Caloris Basin, also called Caloris Planitia, is an Impact crater on Mercury about 1550 km in Diameter, one of the largest Mare Imbrium, Latin for "Sea of Showers" or "Sea of Rains" is a vast Lunar mare (mahr'-ay filling a basin on Earth 's Moon Isidis Planitia is a plain located inside a giant impact basin on Mars, centered at. Mare Tranquillitatis ( Latin for Sea of Tranquility) is a Lunar mare that sits within the Tranquillitatis basin on Earth 's Moon Argyre Planitia is a plain located in the Argyre Impact basin in the southern highlands of Mars. Mare Serenitatis (the "sea of serenity" is a Lunar mare that sits just to the east of Mare Imbrium on Earth's moon. Mare Nubium ("sea of clouds" is a Lunar mare in the Nubium basin on the Moon's near side Beethoven is a crater at latitude -20 longitude 124 on Mercury. Valhalla is the largest multi-ring structure Impact crater on Jupiter 's moon Callisto. Hertzsprung is an enormous lunar crater that is located on the far side of the Moon, beyond the western limb Huygens is an impact crater on mars named in honour of the Dutch astronomer mathematician and physicist Christiaan Huygens. Schiaparelli is an impact crater on Mars named after Giovanni Schiaparelli located in the Schiaparelli hemisphere. Korolev is a large lunar crater of the walled plain type named for Soviet rocket engineer Sergey Korolyov. Odysseus is the largest crater on Saturn 's moon Tethys. It is 400 km across 2/5 of the moon's diameter Tolstoj is a large ancient Impact crater at latitude -15 longitude 165 on Mercury. Goethe Basin is a 383 km diameter Impact basin at 785° N 445° W on Mercury. Like a target ring bull's-eye the Lunar mare Mare Orientale (the "eastern sea" is one of the most striking large scale lunar features Asgard is the second largest multi-ring structure ( Impact crater) on Jupiter 's moon Callisto, measuring 1600 km in diameter Vredefort crater is the largest verified Impact crater on Earth. Mead is an Impact crater on Venus named in honor of the Cultural anthropologist Margaret Mead. [2] Large basins, some unnamed but mostly smaller than 300 km, can also be found on Saturn's moons Dione, Rhea and Iapetus.
See also
- Caldera
- Cretaceous–Tertiary extinction event
- Impact event
- Impact depth
- Nemesis
- Rampart crater
- Ray system
References
- Charles A. A caldera is a cauldron-like volcanic feature formed by the collapse of land following a volcanic eruption The Cretaceous–Tertiary extinction event, which occurred approximately ( Ma) was a large-scale mass extinction of animal and plant species in a geologically See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically The physicist Sir Isaac Newton first developed this idea to get rough approximations for the impact depth for Projectiles travelling at high velocities Nemesis is a hypothetical Red dwarf star or Brown dwarf, orbiting the Sun at a distance of about 50000 to 100000 AU, somewhat Rampart craters are a specific type of Martian Impact crater which are accompanied by distinctive fluidized Ejecta features A ray system comprises the radial streaks of fine Ejecta thrown out during the formation of an Impact crater. Wood and Leif Andersson, New Morphometric Data for Fresh Lunar Craters, 1978, Proceedings 9th Lunar and Planet. Sci. Conf.
- Bond, J. W. , "The development of central peaks in lunar craters", Moon and the Planets, vol. 25, Dec. 1981.
- Melosh, H. J. , 1989, Impact cratering: A geologic process: New York, Oxford University Press, 245 p.
External links
- Study of a South Carolina crater
- The Geological Survey of Canada Crater database, 172 impact structures
- A recent news report about tektites
- Aerial Explorations of Terrestrial Meteorite Craters
- Google Earth Placemarker based on the Geological Survey of Canada Crater database (KML)
- All 172 confirmed meteor impact sites on earth, viewable in Google Earth (Largest, Most recent, Per continent, Including size indicator)
- Impact sites, with individual bibliographies
- Solarviews: Terrestrial Impact Craters
- Earth Impact Database
- Giant Crater Found: Tied to Worst Mass Extinction Ever
- WA Geological Survey Meteorite Impacts in Western Australia
- Terrestrial Impact Craters
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