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Atoka Formation
Named after Atoka County, Oklahoma, the Atoka Formation is a geologic formation in central and western Arkansas, eastern Oklahoma, central and western Texas, and eastern New Mexico. It is the surface rock of the Boston Mountains and dominates exposures in the Frontal Ouachita Mountains of the Arkansas River Valley. Sedimentology The Atoka Formation is a sequence of marine sandstone, sandstones, siltstone, siltstones, and shale, shales, and may be as thick at 25,000 feet in the Ouachita Mountains. The formation is conformable with the Bloyd_Formation, Bloyd Shale in the Boston Mountains and the Johns Valley Formation in the Ouachita Mountains. Paleofauna Conodonts * ''Cavusgnathus'' : ''C. lauta'' : ''C. sinuata'' * ''Gnathodus'' : ''G. wapanuckensis'' * ''Gondolella'' : ''G. bella'' * ''Hindeodella'' * ''Ligonodina'' : ''L. lexingtonensis'' * ''Ozarkodina'' : ''O. recta'' * ''Polygnathodella'' : ''P. attenuata'' : ''P. ouachitensis'' * ''Streptognathodus'' : ''S. cancellosus'' : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formation
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 Wer ... [...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] |
Fusulinella
The Fusulinidae is a family of fusulinacean foraminifera from the upper Carboniferous (Lower Pennsylvanian, Morrowan) to the Upper Permian (Guadalupian The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± ...), tests of which are fusiform to subcylindrical with walls of two to four layers. Are planispirally coiled throughout or with early whorls at a distinct angle to the later plane of coiling. Septa, flat to well fluted; tunnel, single; chomata variable in development. Taxonomy The Fusulinidae is divided into the following subfamilies, ordered as in Loeblich and Tappan, 1988. Fusulinellinae, Staff and Wedekind 1910. Fusulinidae with flat or slightly fluted septa, wall of three or four layers including diaphanotheca and generally pronounced outer tectorium. U Carb - U Permian (as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptognathodus
''Streptognathodus'' is an extinct genus of conodonts from the Late Carboniferous to Early Permian. Use in stratigraphy Late Carboniferous The top of the Kasimovian stage is close to the first appearance of ''Streptognathodus zethus''. The golden spike for the Kasimovian stage has not yet been assigned (in 2008). The Kasimovian is subdivided into three conodont biozones: *''Idiognathodus toretzianus'' Zone *''Idiognathodus sagittatus'' Zone *''Streptognathodus excelsus'' and ''Streptognathodus makhlinae'' Zone The base of the Gzhelian is at the first appearance of ''Streptognathodus zethus''. The top of the stage (also the top base of the Silesian and the base of the Permian system) is at the first appearance of ''Streptognathodus isolatus'' within the ''Streptognathus "wabaunsensis"'' chronocline. The Gzhelian stage is subdivided into five biozones, based on the conodont genus ''Streptognathodus'': * ''Streptognathodus wabaunsensis'' and ''Streptognathodus bellus'' Zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygnathodella
''Polygnathodella'' is an extinct genus of conodont. Glen K. Merrill stated in 1963 that "conodont workers have considered ''Idiognathoides'' to be a junior synonym of ''Polygnathodella'' but it now proves to be a junior synonym of ''Cavusgnathus ''Cavusgnathus'' is an extinct genus of conodonts. Glen K. Merrill A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Whittow defines it as ...''. ''Polygnathodella'' and ''Cavusgnathus'' are shown to form a transitional series."Polygnathodella Harlton, 1933, or Idiognathoides Harris and Hollingsworth, 1933? Glen K. Merrill, Journal of Paleontology, March 1963, volume 37, issue 2abstract References External links * * Conodont genera Pennsylvanian conodonts Fossil taxa described in 1933 {{conodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozarkodina
''Ozarkodina'' is an extinct genus of conodonts in the family Spathognathodontidae. Use in stratigraphy ''Ozarkodina snajdri'' forms a subdivision of the '' Pseudomonoclimacis'' latilobus graptolite zone in the Burgsvik beds Silurian formation in Sweden. An ''Ozarkodina snajdri crispa'' zone has also been identified in the Wills Creek in Virginia. ''Ozarkodina derenjalensis'' is found in the Silurian of the Niur Formation in Iran.A new early Silurian prioniodontid conodont with three P elements from Iran and associated species. Peep Männik, C. Giles Miller and Vachik Hairapetian, Acta Palaeontologica Polonica, 2015, volume 60, issue 3, pages 733–746, The Kellwasser event in the Devonian which saw the extinction of all ''Ozarkodina'' species is reported in the list of Global Boundary Stratotype Sections and Points. References External links ''Ozarkodina''at fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gondolella
''Gondolella'' is an extinct genus of conodonts in the family Gondolellidae Gondolellidae is an extinct family of conodonts in the order Ozarkodinida. There are three subfamilies: Mullerinae, Neogondolellinae and Novispathodinae. References External links * * Ozarkodinida families {{conodont-st ....The Pennsylvanian conodont genus Gondolella Stauffer & Plummer, 1932: reinterpretation of the original type specimens and concepts. Glen K. Merrill and Peter H. Von Bitter, Journal of Micropalaeontology, volume 26, issue 1, pages 41-46, April 2007, References External links * * Ozarkodinida genera Pennsylvanian conodonts Fossil taxa described in 1932 {{conodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathodus
''Gnathodus'' is an extinct conodont genus in the family Idiognathodontidae. Use in stratigraphy The Tournaisian, the oldest age of the Mississippian (also known as Lower Carboniferous), contains eight conodont biozones, 3 of which are defined by ''Gnathodus species'': * the zone of ''Gnathodus pseudosemiglaber'' and '' Scaliognathus anchoralis'' * the zone of ''Gnathodus semiglaber'' and ''Polygnathus communis'' * the zone of ''Gnathodus typicus'' and ''Siphonodella isosticha'' The Visean, the second age of the Mississippian, contains four conodont biozones, two of which are defined by ''Gnathodus'' species: * the ''Gnathodus bilineatus'' Zone * the ''Gnathodus texanus'' Zone The Serpukhovian The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed b ..., the third or youngest age o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavusgnathus
''Cavusgnathus'' is an extinct genus of conodonts. Glen K. Merrill A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Whittow defines it as a "Scottish term for a deep valley in the Highlands" that is "narrower ... stated in 1963 that "conodont workers have considered '' Idiognathoides'' to be a junior synonym of '' Polygnathodella'' but it now proves to be a junior synonym of ''Cavusgnathus''. ''Polygnathodella'' and ''Cavusgnathus'' are shown to form a transitional series."Polygnathodella Harlton, 1933, or Idiognathoides Harris and Hollingsworth, 1933? Glen K. Merrill, Journal of Paleontology, March 1963, volume 37, issue 2abstract References External links * * Ozarkodinida genera Pennsylvanian conodonts Gzhelian life Kasimovian life Fossil taxa described in 1933 Pennsylvanian first appearances Pennsylvanian extinctions {{conodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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