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Travesser Formation
The Travesser Formation is a geologic formation in northeastern New Mexico, southeastern Colorado, westernmost Oklahoma, and northwestern Texas, particularly in the Dry Cimarron valley. It preserves fossils dating back to the late Triassic period. Description The formation is mostly reddish-brown clay-rich siltstone and fine-grained sandstone, with sandstone beds up to thick. The formation also contains conglomerate lenses up to . The total thickness of the formation is . The formation unconformably overlies the Baldy Hill Formation and underlies the Sloan Canyon Formation or locally the Exeter Sandstone. The formation is usually assigned to the Dockum Group. The proposal of Spencer G. Lucas and his collaborators to abandon the Dockum Group, possibly in favor of the Chinle Group, is highly controversial. Formations A fossil phytosaur skull and metoposaurids have been found in the formation. History of investigation The formation was first named by Baldwin and Muelberger i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In New Mexico
This article contains a list of fossil-bearing stratigraphic units in the state of New Mexico, U.S. Sites See also * Paleontology in New Mexico References * {{DEFAULTSORT:Fossiliferous stratigraphic units in New Mexico New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ... Stratigraphic units Stratigraphy of New Mexico New Mexico geography-related lists United States geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metoposaurid
Metoposauridae is an extinct family of trematosaurian temnospondyls. The family is known from the Triassic period. Most members are large, approximately long and could reach 3 m long.Brusatte, S. L., Butler R. J., Mateus O., & Steyer S. J. (2015). A new species of Metoposaurus from the Late Triassic of Portugal and comments on the systematics and biogeography of metoposaurid temnospondyls. Journal of Vertebrate Paleontology. e912988., 2015: Metoposaurids can be distinguished from the very similar mastodonsauroids by the position of their eyes, placed far forward on the snout. Taphonomy Several mass accumulations of metoposaurid fossils are known from the southwestern United States and Morocco. These have often been interpreted as the result of mass deaths from droughts. Many individuals would have died in one area, creating a dense bone bed once fossilized. These mass accumulations of metoposaurids are often dominated by one taxa, such as ''Anaschisma'' or ''Metoposaurus''. Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytosaur
Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent groupings containing the same species, but some studies have identified non-phytosaurid phytosaurians. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution. The name "phytosaur" means "plant reptile", as the first fossils of phytosaurs were mistakenly thought to belong to plant eaters. The name is misleading because the sharp teeth in phytosaur jaws clearly show that they were predators. For many years, phytosaurs were considered to be the most basal group of Pseudosuchia (crocodile-line archosaurs), meaning that they were thought to be more closely related to the crocodilians than to birds (the other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinle Group
The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In New Mexico, it is often raised to the status of a geological group, the Chinle Group. Some authors have controversially considered the Chinle to be synonymous to the Dockum Group of eastern Colorado and New Mexico, western Texas, the Oklahoma panhandle, and southwestern Kansas. The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains.GEOLEX database entry for Chinle USGS (viewed 19 March 2006) A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spencer G
Spencer may refer to: People *Spencer (surname) ** Spencer family, British aristocratic family **List of people with surname Spencer *Spencer (given name), a given name (including a list of people with the name) Places Australia * Spencer, New South Wales, on the Central Coast *Spencer Gulf, one of two inlets on the South Australian coast United States * Spencer, Idaho * Spencer, Indiana *Spencer, Iowa *Spencer, Massachusetts ** Spencer (CDP), Massachusetts * Spencer, Missouri *Spencer, Nebraska * Spencer, New York **Spencer (village), New York *Spencer, North Carolina * Spencer, Ohio *Spencer, Oklahoma *Spencer, South Dakota * Spencer, Tennessee * Spencer, Virginia *Spencer, West Virginia *Spencer, Wisconsin **Spencer (town), Wisconsin *Spencer County, Indiana *Spencer County, Kentucky Ireland *Spencer Dock, North Wall, Dublin Arts and entertainment Fictional characters *Spencer, character in ''Beyblade'' *Spencer, character from ''Final Fantasy Mystic Quest'' * Spencer fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exeter Sandstone
The Exeter Sandstone is a geologic formation exposed in northeastern New Mexico. Its age is poorly controlled, but it is thought to have been deposited during the middle Jurassic. Description The formation consists of up to of white to pale pink crossbedded quartz sandstone. It unconformably overlies the Sheep Pen Sandstone and is in turn overlain by the Bell Ranch Formation. The Exeter Formation varies greatly in thickness, with the maximum thickness in synclinal valleys of the underlying Dockum Group and the formation being absent on some anticlinal crests of the Dockum Group. The formation has long been thought to have formed in the eastern part of the Entrada Formation dune sea and thus to be correlative with the Entrada Formation, and Spencer G. Lucas and coinvestigators recommended demoting the Exeter Sandstone to member rank within the Entrada Formation. However, age control is poor on the Exeter Sandstone, and other investigators have retained the Exeter Sandstone at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity (geology)
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conglomerate (geology)
Conglomerate () is a clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts. A conglomerate typically contains a matrix of finer-grained sediments, such as sand, silt, or clay, which fills the interstices between the clasts. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay. Conglomerates form by the consolidation and lithification of gravel. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. In terms of origin and depositional mechanisms, they are closely related to sandstones and exhibit many of the same types of sedimentary structures, e.g., tabular and trough cross-bedding and graded bedding.Boggs, S. (2006) ''Principles of Sedimentology and Stratigraphy.'', 2nd ed. Prentice Hall, New York. 662 pp. Friedman, G.M. (2003) ''Classification of sediments and sedimentary rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, pp.381-382 Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock ( clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
