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Powell Formation
The Powell Formation or Powell Dolomite is a geologic formation in northern Arkansas, southeast Missouri and Virginia. It contains gastropod, cephalopod, and trilobite fossils dating back to the Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ... Period. See also * List of fossiliferous stratigraphic units in Arkansas * List of fossiliferous stratigraphic units in Missouri * List of fossiliferous stratigraphic units in Virginia References * Ordovician Arkansas Ordovician Missouri Ordovician geology of Virginia Ordovician Tennessee Ordovician southern paleotemperate deposits Ordovician southern paleotropical deposits Dolomite formations of the United States Shale formations of the United States Sandstone formations of the United States Chert formations G ... [...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 (geology), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale Formations Of The United States
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g., kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the narrower sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable bedding plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolomite Formations Of The United States
Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincorporated community *Dolomites, a section of the Alps * Lucanian Dolomites, a mountain range in southern Italy *Manila Dolomite Beach, formally known as the Manila Baywalk Dolomite Beach, an urban artificial beach in Manila, Philippines *Triumph Dolomite (1934–1940), a sporting car made by Triumph Motor Company *Triumph Dolomite, a small car made by the British Leyland Corporation in the 1970s and 1980s See also *''Dolemite'', 1975 blaxploitation feature film and the name of its principal character **''Shaolin Dolemite'', a 1999 in-name-only sequel to ''Dolemite'' **"Dolemite", the opening track on ''Tore Down House'', a 1997 album by Scott Henderson; the track features samples from the film *''Dolemite Is My Name ''Dolemite Is My Name' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician Southern Paleotropical Deposits
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Megaannum, Ma (million years ago) to the start of the Silurian Period Ma. The Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician Southern Paleotemperate Deposits
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Ma (million years ago) to the start of the Silurian Period Ma. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Virginia
This article contains a list of fossil-bearing stratigraphic units in the state of Virginia, U.S. Sites See also * Paleontology in Virginia References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Virginia Virginia Stratigraphic units A stratigraphic unit is a volume of Rock (geology), rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrography, petrographic, lithology, lithologic or paleontology, ... Stratigraphy of Virginia Virginia geography-related lists United States geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Missouri
This article contains a list of fossil-bearing stratigraphic units in the state of Missouri, U.S. Sites See also * Paleontology in Missouri References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Missouri Missouri Stratigraphic units A stratigraphic unit is a volume of Rock (geology), rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrography, petrographic, lithology, lithologic or paleontology, ... Stratigraphy of Missouri Missouri geography-related lists United States geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
