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Impact Glass
Impactite is rock created or modified by one or more impacts of a meteorite. Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. On Earth, impactites consist primarily of modified terrestrial material, sometimes with pieces of the original meteorite. Formation When a large meteorite hits a planet, it can radically deform the rocks and regolith that it hits. The heat, pressure, and shock of the impact changes these materials into impactite. Only very massive impacts generate the heat and pressure needed to transform a rock, so impactites are created rarely. Characteristics Impactite includes shock-metamorphosed target rocks, melts (suevites) and mixtures of the two, as well as sedimentary rocks with significant impact-derived components (shocked mineral grains, tektites, anomalous geochemical signatures, etc.). In June 2015, NASA reported that impact glass has been detected on the planet Mars. Such mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Lattice
In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystal, crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of Three-dimensional space (mathematics), three-dimensional space in matter. The smallest group of particles in a material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive Translation (geometry), translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice. The lengths of principal axes/edges, of the unit cell and angles between them are lattice constants, also called ''lattice parameters'' or ''cell parameters''. The symmetry properties of a crystal are described by the concept of space groups. All possi ... [...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] |
Darwin Crater
Darwin Crater is a suspected meteorite impact crater in Western Tasmania about south of Queenstown, just within the Franklin-Gordon Wild Rivers National Park. The crater is expressed as a rimless circular flat-floored depression, in diameter, within mountainous and heavily forested terrain. It is east of the West Coast Range and the former North Mount Lyell Railway formation. Discovery and description The crater was discovered by the geologist R. J. Ford in 1972, after a search for the source of Darwin glass, an impact glass found over more than of southwestern Tasmania. Geophysical investigations and drilling have shown that the crater is filled with up to of breccia capped by Pleistocene lake sediments. Although definitive proof of an impact origin of the crater is lacking, the impact hypothesis is strongly supported by the relationship of the glass to the crater, as well as the stratigraphy and deformation of the crater-filling material. If the crater is indeed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charlevoix Impact Structure
The Charlevoix impact structure is a large eroded meteorite impact structure in the Charlevoix region of Quebec, Canada. Only part of the impact structure is exposed at the surface, the rest lying beneath the Saint Lawrence River. Description The original impact structure is estimated to have been in diameter and the age of the impact is estimated to be 450 ± 20 million years (Ordovician to Silurian age).Schmieder, M., Shaulis, B.J., Lapen, T.J., Buchner, E. and Kring, D.A., 2019. ''In situ U–Pb analysis of shocked zircon from the Charlevoix impact structure, Québec, Canada.'' ''Meteoritics & Planetary Science.'' 54(8) pp. 1808-1827. The projectile was probably a stony asteroid, at least in diameter, and weighing an estimated . The Mont des Éboulements, situated in the exact centre of the impact structure, is interpreted as the central uplift, a consequence of elastic rebound.Interpretation Centre, Parc national des Grands-Jardins, Charlevoix The impact structure is clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barringer Crater
Meteor Crater, or Barringer Crater, is an impact crater about east of Flagstaff and west of Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fragments of the meteorite are officially called the Canyon Diablo Meteorite, after the adjacent Canyon Diablo. Meteor Crater lies at an elevation of above sea level. It is about in diameter, some deep, and is surrounded by a rim that rises above the surrounding plains. The center of the crater is filled with of rubble lying above crater bedrock. One of the features of the crater is its squared-off outline, believed to be caused by existing regional jointing (cracks) in the strata at the impact site. Despite an attempt to make the crater a public landmark, the crater remains privately owned by the Barringer family to the present day through their Barringer Crater Company. The Lunar and Planetary Institute, the American Museum of Natural History, and other science institutes pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-G
A&G, AG, Ag or ag may refer to Businesses and organizations * A&G Railroad (former reporting mark AG) * Action Group (Nigeria), a political party during the Nigerian First Republic * Aktiengesellschaft, a German type of corporation * Assemblies of God, the world's largest Pentecostal organization * Associated Group, a Pakistani company * Astronomische Gesellschaft, a German astronomical society * IATA code for Aruba Airlines * Australian Greens, a political party Entertainment * ''American Gladiators'' (1989–1996 TV series) * ''American Gladiators'' (2008 TV series) * Atarashii Gakko!, a Japanese girl group Government and military * Adjutant general, the Army branch responsible for personnel * Administrator-General of South West Africa, the head of government in Namibia prior to independence in 1990 * Aerographer's mate, a rating or specialty in the US Navy that deals with weather and oceanography * American Holland-class submarine (''Amerikansky Golland''), a class o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alamo Bolide Impact
The Alamo bolide impact occurred 377–378 million years ago, when one or more hypervelocity objects from space slammed into shallow marine waters at a site that is now the Devonian Guilmette Formation of the Worthington Mountains and Schell Creek Range of southeastern Nevada; the event is named for breccias of metamorphosed crushed rock deposits, found near the town of Alamo, Nevada (the "Alamo Breccia"). This catastrophic impact event resulted in what is one of the best-exposed and has become the most accurately dated impact events; it occurred within the Frasnian age of the Devonian at about 377-378 Ma, a moment in time that was about 5.9 Ma prior to the Frasnian/Famennian extinction events, which it is unlikely to have affected. The actual impact site has not yet been significantly documented—even its precise diameter and its internal structural features are not yet clear enough to make speculations on the mass and trajectory genuinely useful. The "tectonic overprin ... [...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] |
