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Dry Mesa Quarry
The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them ''Ceratosaurus'', '' Supersaurus'', and ''Torvosaurus''. The quarry is found within the Uncompahgre National Forest. History In 1971, a large theropod phalanx (''Torvosaurus'' ''tanneri'') was discovered at Dry Mesa by Ed and Vivian Jones of Delta, Colorado. The find was reported to James A. Jensen of Brigham Young University (BYU) who commenced quarrying operations in 1972. In 1973, Brigham Young University cooperated with producer Steve Linton and director John Linton in order to produce '' The Great Dinosaur Discovery'', a 1-hour-long color documentary showing Jensen's on-site finds in Dry Mesa. First released on November 13, 1973, in local "Egyptian Theater" in Delta, and subsequently aired on several USA TV channels, ''The G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Mesa Quarry
The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them ''Ceratosaurus'', '' Supersaurus'', and ''Torvosaurus''. The quarry is found within the Uncompahgre National Forest. History In 1971, a large theropod phalanx (''Torvosaurus'' ''tanneri'') was discovered at Dry Mesa by Ed and Vivian Jones of Delta, Colorado. The find was reported to James A. Jensen of Brigham Young University (BYU) who commenced quarrying operations in 1972. In 1973, Brigham Young University cooperated with producer Steve Linton and director John Linton in order to produce '' The Great Dinosaur Discovery'', a 1-hour-long color documentary showing Jensen's on-site finds in Dry Mesa. First released on November 13, 1973, in local "Egyptian Theater" in Delta, and subsequently aired on several USA TV channels, ''The G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velocities
Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of bodies. Velocity is a physical vector quantity; both magnitude and direction are needed to define it. The scalar absolute value (magnitude) of velocity is called , being a coherent derived unit whose quantity is measured in the SI (metric system) as metres per second (m/s or m⋅s−1). For example, "5 metres per second" is a scalar, whereas "5 metres per second east" is a vector. If there is a change in speed, direction or both, then the object is said to be undergoing an ''acceleration''. Constant velocity vs acceleration To have a ''constant velocity'', an object must have a constant speed in a constant direction. Constant direction const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antidune
An antidune is a bedform found in fluvial and other channeled environments. Antidunes occur in supercritical flow, meaning that the Froude number is greater than 1.0 or the flow velocity exceeds the wave velocity; this is also known as upper flow regime. In antidunes, sediment is deposited on the upstream (stoss) side and eroded from the downstream (lee) side, opposite lower flow regime bedforms. As a result, antidunes migrate in an upstream direction, counter to the current flow. Antidunes are called in-phase bedforms, meaning that the water surface elevation mimics the bed elevation; this is due to the supercritical flow regime. Antidune bedforms evolve rapidly, growing in amplitude as they migrate upstream. The resultant wave at the water's surface also increases in amplitude. When that wave becomes unstable, breaks and washes downstream, much of the antidune bedform may be destroyed. Formation Antidunes are typically found in fluvial environments in shallow areas with a high f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arenite
Arenite (Latin: ''arena'', "sand") is a sedimentary clastic rock with sand grain size between 0.0625 mm (0.00246 in) and 2 mm (0.08 in) and contain less than 15% matrix. The related adjective is ''arenaceous''. The equivalent Greek-derived term is psammite, though this is more commonly used for metamorphosed sediments. Since it refers to grain size rather than chemical composition, the term is used for example in the classification of clastic carbonatic limestones, as the granulometrically equivalent term sandstone is not appropriate for limestone. Other arenites include sandstones, arkoses, greensands, and greywackes. Arenites mainly form by erosion of other rocks or turbiditic re-deposition of sands. Some arenites contain a varying amount of carbonatic components and thus belong to the rock-category of carbonatic sandstones or silicatic limestones. Arenites often appear as massive or bedded medium-grained rocks with a middling- to wide-spaced preferred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrates
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Flood
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may also occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding. Flash floods are a significant hazard, causing more fatalities in the U.S. in an average year than lightning, tornadoes, or hurricanes. Flash floods can also deposit large quantities of sediments on floodplains and can be destructive of vegetation cover not adapted to frequent flood conditions. Causes Flash floods most often occur in dry areas that have recently received precipitation, but they may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, and O. Zolina, 2021Water Cycle Changes In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1055–1210, doi:10.1017/9781009157896.010. This means that a drought is "a moisture deficit relative to the average water availability at a given location and season". A drought can last for days, months or years. Drought ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototheria
Prototheria (; from Greek πρώτος, ''prōtos'', first, + θήρ, ''thēr'', wild animal) is a subclass to which the orders Monotremata, Morganucodonta, Docodonta, Triconodonta and Multituberculata have been assigned, although the validity of the subclass has been questioned. Most of the animals in this group are extinct. The egg-laying monotremes are known from fossils of the Cretaceous and Cenozoic periods; they are represented today by the platypus and several species of echidna. The names Prototheria, Metatheria, and Eutheria (meaning "first beasts", "changed beasts", and "true beasts", respectively) refer to the three mammalian groupings of which we have living representatives. Each of the three may be defined as a total clade containing a living crown-group (respectively the Monotremata, Marsupialia and Placentalia) plus any fossil species which are more closely related to that crown-group than to any other living animals. The threefold division of living mammals int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lungfish
Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. Today there are only six known species of lungfish, living in Africa, South America, and Australia. The fossil record shows that lungfish were abundant since the Triassic. While vicariance would suggest this represents an ancient distribution limited to the Mesozoic supercontinent Gondwana, the fossil record suggests advanced lungfish had a widespread freshwater distribution and the current distribution of modern lungfish species reflects extinction of many lineages subsequent to the breakup of Pangaea, Gondwana and Laurasia. Lungfish have historically been referred to as salamanderfish, but this t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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