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Allen Formation
The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous (middle Campanian to early Maastrichtian.Salgado et al., 2007 Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 600-604. . Description The stratotype of the formation was defined by Uliana and Dellapé in 1981 in the eastern area of the Bajo de Añelo, where the relation between base and top is clearly exposed. The deposits are mostly clastic, interbedded with banks of limestone and layers of anhydrite, which were defined continental and shallow marine facies associated with semiarid conditions.Armas & Sánchez, 2015, p.101 The interpreted sedimentary paleoenvironments range from purely continental such as ephemer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Auca Mahuida
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Auca or AUCA may refer to : * Auca (titular diocese), the former Catholic bishopric of (Villafranca Montes de) Oca in Spain, now a Latin titular see * A pejorative name for the native Huaorani people in Ecuador ** Operation Auca, an endeavor to evangelize the Huaorani tribe * ''Auca'' (genus), a genus of butterflies in the subfamily Satyrinae of the family Nymphalidae * Auca (cartoon), a Catalan genre of story in pictures * Sociedad Deportiva Aucas, a football club from Quito, Ecuador ; AUCA as an acronym : * Adventist University of Central Africa * American University of Central Asia The American University of Central Asia (AUCA) (russian: Американский университет в Центральной Азии; ky, Борбордук Азиядагы Америка Университети), formerly the ''Kyrgyz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Allen Formation Fauna
Allen, Allen's or Allens may refer to: Buildings * Allen Arena, an indoor arena at Lipscomb University in Nashville, Tennessee * Allen Center, a skyscraper complex in downtown Houston, Texas * Allen Fieldhouse, an indoor sports arena on the University of Kansas campus in Lawrence * Allen House (other) * Allen Power Plant (other) Businesses * Allen (brand), an American tool company *Allen's, an Australian brand of confectionery *Allens (law firm), an Australian law firm formerly known as Allens Arthur Robinson * Allen's (restaurant), a former hamburger joint and nightclub in Athens, Georgia, United States *Allen & Company LLC, a small, privately held investment bank * Allens of Mayfair, a butcher shop in London from 1830 to 2015 *Allens Boots, a retail store in Austin, Texas * Allens, Inc., a brand of canned vegetables based in Arkansas, US, now owned by Del Monte Foods * Allen's department store, a.k.a. Allen's, George Allen, Inc., Philadelphia, USA People * Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Austroraptor Reconstruction
''Austroraptor'' ( ) is a genus of large dromaeosaurid dinosaur that lived during the Late Cretaceous Period in what is now Argentina. ''Austroraptor'' was a large-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at in length. It is one of the largest dromaeosaurids known, with only ''Achillobator'', ''Dakotaraptor'', and ''Utahraptor'' approaching or surpassing it in length. Discovery and naming The type specimen of ''Austroraptor cabazai'', holotype MML-195, was recovered in the Bajo de Santa Rosa locality of the Allen Formation, in Río Negro, Argentina. The specimen was collected in 2002 by the team of Fernando Emilio Novas of the '' Museo Argentino de Ciencias Naturales''. It consists of a fragmentary skeleton including parts of the skull, lower jaw, a few neck and torso vertebrae, some ribs, a humerus, and assorted bones from both legs. The specimen was prepared by Marcelo Pablo Isasi and Santiago Reuil. In 2008, the type species ''Austroraptor ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Austroraptor
''Austroraptor'' ( ) is a genus of large dromaeosaurid dinosaur that lived during the Late Cretaceous Period (geology), Period in what is now Argentina. ''Austroraptor'' was a large-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at in length. It is one of the largest dromaeosaurids known, with only ''Achillobator'', ''Dakotaraptor'', and ''Utahraptor'' approaching or surpassing it in length. Discovery and naming The type specimen of ''Austroraptor cabazai'', holotype MML-195, was recovered in the Bajo de Santa Rosa locality of the Allen Formation, in Río Negro (Argentina), Río Negro, Argentina. The specimen was collected in 2002 by the team of Fernando Emilio Novas of the ''Museo Argentino de Ciencias Naturales''. It consists of a fragmentary skeleton including parts of the skull, lower jaw, a few neck and torso vertebrae, some ribs, a humerus, and assorted bones from both legs. The specimen was prepared by Marcelo Pablo Isasi and Santiago Reuil. In 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Aeolosaurus
''Aeolosaurus'' (; "Aeolus' lizard") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. Like most sauropods, it would have been a quadrupedal herbivore with a long neck and tail. ''Aeolosaurus'' is well known for a titanosaur, as it is represented by the remains of several individuals belonging to at least two species. However, like most titanosaurs, no remains of the skull are known. The holotype of ''Aeolosaurus rionegrinus'' consists of a series of seven tail vertebrae, as well as parts of both forelimbs and the right hindlimb. It was discovered in the Angostura Colorada Formation in Argentina, which dates from the Campanian stage of the Late Cretaceous, about 83 to 74 million years ago. The species ''A. maximus'' was transferred over to the new genus '' Arrudatitan'' in 2021. Etymology This dinosaur is named after the Greek mythological figure Aeolus, Keeper of the Winds in Homer's Odyssey, because of the frequent wind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Evaporite
An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean deposits, and non-marine, which are found in standing bodies of water such as lakes. Evaporites are considered sedimentary rocks and are formed by chemical sediments. Formation of evaporite rocks Although all water bodies on the surface and in aquifers contain dissolved salts, the water must evaporate into the atmosphere for the minerals to precipitate. For this to happen, the water body must enter a restricted environment where water input into this environment remains below the net rate of evaporation. This is usually an arid environment with a small basin fed by a limited input of water. When evaporation occurs, the remaining water is enriched in salts, and they precipitate when the water becomes supersaturated. Evaporite depo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Tidal Flat
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal flat ecosystems are as extensive globally as mangroves, covering at least of the Earth's surface. / They are found in sheltered areas such as bays, bayous, lagoons, and estuaries; they are also seen in freshwater lakes and salty lakes (or inland seas) alike, wherein many rivers and creeks end. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and aquatic animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily. A recent global remote sensing analysis estimated that approximately 50% of the global extent of tidal flats occurs within eight countries (Indonesia, China, Aust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Estuary
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Fluvial
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used. Fluvial processes Fluvial processes include the motion of sediment and erosion or deposition on the river bed. The movement of water across the stream bed exerts a shear stress directly onto the bed. If the cohesive strength of the substrate is lower than the shear exerted, or the bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment, this material can act as tools to enhance wear of the bed ( abrasion). At the same time the fragments themselves are ground down, becoming smaller and more rounded ( attrition). Sediment in rivers is transported as either bedload (the coar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Aeolian Processes
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials and are effective agents in regions with sparse vegetation, a lack of soil moisture and a large supply of unconsolidated sediments. Although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts. The term is derived from the name of the Greek god Aeolus, the keeper of the winds. Definition and setting ''Aeolian processes'' are those processes of erosion, transport, and deposition of sediments that are caused by wind at or near the surface of the earth. Sediment deposits produced by the action of wind and the sedimentary structures characteristic of these deposits are also described as ''aeolian''. Aeolian processes are most important in areas where there is little ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |