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Shocked Quartz
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These planes, which show up as lines under a microscope, are called planar deformation features (PDFs), or shock lamellae. Discovery Shocked quartz was discovered following underground nuclear weapons testing, which generated the intense pressures required to alter the quartz lattice. Eugene Shoemaker showed that shocked quartz is also found inside craters created by meteor impact, such as the Barringer Crater and Chicxulub crater. The presence of shocked quartz supports that such craters were formed by impact, because a volcanic eruption would not generate the required pressure. Lightning is now known to contribute to the surface record of shocked quartz grains, complicating identification of hypervelocity impact features. Formation Shocke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suvasvesi Shocked Quartz
Suvasvesi is a lake in Eastern Finland near the city of Kuopio. Suvasvesi consists of two circular open lakes, Kuukkarinselkä in north and Haapaselkä in south. The lakes are separated by a group of islands. The lake has 688 islands in total. The area of the lake is making it the 18th largest lake in Finland. Kuukkarinselkä is the third deepest lake in Finland measuring in the deepest point. In 2001, shatter cones were found in Kuukkarinselkä making it the 6th known impact crater in Finland. The crater, usually referred as Suvasvesi North crater, is located in the center of Kuukkarinselkä and measures about in diameter. Its age is estimated to be about 85 Ma but the Earth Impact Database The Earth Impact Database is a database of confirmed impact structures or impact crater, craters on Earth. It was initiated in 1955 by the Dominion Observatory, Ottawa, under the direction of Carlyle Smith Beals, Carlyle S. Beals. Since 2001, it h ... (EID) gives a broader span of less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Event
An impact event is a collision between astronomical objects causing measurable effects. Impact events have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and Biosphere, biospheric consequences, as the impacting body is usually traveling at several kilometres per second (km/s), with a minimum impact speed of 11.2 km/s (7.0 mi/s) for bodies striking Earth. Atmosphere, While planetary atmospheres can mitigate some of these impacts through the effects of atmospheric entry, many large bodies retain sufficient energy to reach the surface and cause substantial damage. This results in the formation of Impact crater, impact craters and Impact structure, structures, shaping the dominant landforms found across various types of solid objects found in the Solar System. Their prevalence and ubiquity pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudotachylite
Pseudotachylyte (sometimes written as pseudotachylite) is an extremely fine-grained to glassy, dark, cohesive rock occurring as veinsTrouw, R.A.J., C.W. Passchier, and D.J. Wiersma (2010) ''Atlas of Mylonites- and related microstructures.'' Springer-Verlag, Berlin, Germany. 322 pp. that form through frictional melting and subsequent quenching during earthquakes, large-scale landslides, and impacts events. Chemical composition of pseudotachylyte generally reflects the local bulk chemistry, though may skew to slightly more mafic compositions due to the preferential incorporation of hydrous and ferro-magnesian minerals (mica and amphibole, respectively) into the melt phase. Pseudotachylyte was first documented by Shand in the Vredefort Impact Structure and was named due to its close resemblance to tachylyte, a basaltic glass. Though pseudotachylyte is reported to have a glassy appearance, they are extremely susceptible to alteration and are thus rarely found to be entirely compose ... [...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] |
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] |
Nördlingen
Nördlingen (; Swabian: ''Nearle'' or ''Nearleng'') is a town in the Donau-Ries district, in Swabia, Bavaria, Germany, with a population of approximately 20,674. It is located approximately east of Stuttgart, and northwest of Munich. It was built in an impact crater 15 million years old and in diameter—the Nördlinger Ries—of a meteorite which hit with an estimated speed of 70,000 km/h, and left the area riddled with an estimated 72,000 tons of micro-diamonds. Nördlingen was first mentioned in recorded history in 898. The town was the location of two battles during the Thirty Years' War, which took place between 1618 and 1648. Today it is one of very few towns in Germany that still have completely intact city walls—joining the ranks of Rothenburg ob der Tauber, Dinkelsbühl and Berching, all of them in Bavaria. Another attraction in the town is Saint George's Church's steeple, called "Daniel," which is made of a suevite impact breccia that contains shocked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bavaria
Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total land area of Germany, and with over 13.08 million inhabitants, it is the list of German states by population, second most populous German state, behind only North Rhine-Westphalia; however, due to its large land area, its population density is list of German states by population density, below the German average. Major cities include Munich (its capital and List of cities in Bavaria by population, largest city, which is also the list of cities in Germany by population, third largest city in Germany), Nuremberg, and Augsburg. The history of Bavaria includes its earliest settlement by Iron Age Celts, Celtic tribes, followed by the conquests of the Roman Empire in the 1st century BC, when the territory was incorporated into the provinces of Ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium
Iridium is a chemical element; it has the symbol Ir and atomic number 77. This very hard, brittle, silvery-white transition metal of the platinum group, is considered the second-densest naturally occurring metal (after osmium) with a density of as defined by experimental X-ray crystallography. 191Ir and 193Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant. It is one of the most corrosion-resistant metals, even at temperatures as high as . Iridium was discovered in 1803 in the acid-insoluble residues of platinum ores by the English chemist Smithson Tennant. The name ''iridium'', derived from the Greek word ''iris'' (rainbow), refers to the various colors of its compounds. Iridium is one of the rarest elements in Earth's crust, with an estimated annual production of only in 2023. The dominant uses of iridium are the metal itself and its alloys, as in high-performance spark plugs, crucibles for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene
The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the first period of the Cenozoic Era, the tenth period of the Phanerozoic and is divided into the Paleocene, Eocene, and Oligocene epochs. The earlier term Tertiary Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg", although the United States Geological Survey uses the abbreviation "" for the Paleogene on the Survey's geologic maps. Much of the world's modern vertebrate diversity originated in a rapid surge of diversification in the early Paleogene, as survivors of the Cretaceous–Paleogene extinction event took advantage of empty ecolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geological period of the entire Phanerozoic. The name is derived from the Latin , 'chalk', which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation . The Cretaceous was a period with a relatively warm climate, resulting in high Sea level#Local and eustatic, eustatic sea levels that created numerous shallow Inland sea (geology), inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was largely ice-free, although there is some evidence of brief periods of glaciation during the cooler first half, and forests extended to the poles. Many of the dominant taxonomic gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous–Paleogene Boundary
The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at 66 million years, with radiometric dating yielding a more precise age of 66.043 ± 0.043 Ma. The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for some birds. Strong evidence exists that the extinction coincided with a large meteorite impact at the Chicxulub crater and the generally accepted scientific theory is that this impact triggered the extinction event. The word "Cretaceous" is derived from the Latin "creta" ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulgurite
Fulgurites (), commonly called "fossilized lightning", are natural tubes, clumps, or masses of sintered, vitrified, or fused soil, sand, rock, organic debris and other sediments that sometimes form when lightning discharges into ground. When composed of silica, fulgurites are classified as a variety of the mineraloid lechatelierite. When ordinary negative polarity cloud-ground lightning discharges into a grounding substrate, greater than 100 million volts (100 MV) of potential difference may be bridged. Such current may propagate into silica-rich quartzose sand, mixed soil, clay, or other sediments, rapidly vaporizing and melting resistant materials within such a common dissipation regime. This results in the formation of generally hollow and/or vesicular, branching assemblages of glassy tubes, crusts, and clumped masses. Fulgurites have no fixed composition because their chemical composition is determined by the physical and chemical properties of whatever material is bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
