|
Frasnian
The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during the Frasnian Stage, particularly in western Canada and Australia. On land, the first forests were taking shape. In North America, the Antler orogeny peaked, which were contemporary with the Bretonic phase of the Variscan orogeny in Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east .... The Frasnian coincides with the second half of the "charcoal gap" in the fossil record, a time when atmospheric oxygen levels were below 13 percent, the minimum necessary to sustain wildfires. North American subdivisions of the Frasnian include * We ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free- sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants ( pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Rev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genesee Group
The Genesee Formation (Group) is a geologic formation in New York. It is equivalent the Harrell Shale in Pennsylvania. It dates back to the Upper Devonian period. It is the basal unit of the Frasnian and Upper Devonian period. The Genesee Formation was defined by de Witt and Colton, 1959 as all strata between the Middlesex Unit of the Sonyea Group and the Tully Formation, where present or the Moscow Formation where the Tully is not present. Description The Genesee includes several members. Moving westward towards the Findley and Cincinnati Archs the formation thins to less than 9 feet. To the east it feathers in with coarser grained formations. Stratigraphy The Genesee has several members. With coarser clastic material coming mostly from the east there are several members that are feathered to the West River and Penn Yann on the eastern flanks. Below are listed the units found within the Genesee. West River Shale Member Clarke and Luther (1904, p. 28) coined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonyea Group
The Sonyea Group is a geologic group in the northern part of the Appalachian Basin. It preserves fossils dating back to the Devonian period. In the western part, it is divided into the Cashaqua Shale at the top, and the Middlesex Shale at the bottom. In the east, various shale formations are included between the Cashaqua and Middlesex members, including Rye Point Shale, Rock Stream Formation ("Enfield Formation The Enfield Formation is a Formation (stratigraphy), geologic formation in New York (state), New York. It preserves fossils dating back to the Devonian Period (geology), period. See also * List of fossiliferous stratigraphic units in New York R ...") Siltstone, Pulteney shale, Sawmill Creek Shale, Johns Creek Shale and Montour Shale. See also * List of fossiliferous stratigraphic units in Pennsylvania * Paleontology in Pennsylvania References * * Geologic groups of Pennsylvania Devonian Pennsylvania Devonian geology of New York (state) Shale form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Falls Group
The West Falls Group is a geologic group in the Appalachian Basin. It dates back to the Devonian period. Also stratigraphically equivalent to the Portage Group. Description Stratigraphy The West Falls Group is a geologic group in New York. It dates back to the Devonian period. Also stratigraphically equivalent to the Portage Group. The West Falls formation is bounded above by the Java Formation and below by the Sonyea Formation. It comprises the Angola Shale and Rhinestreet Shale Members. It was deposited during the Acadian Orogeny and is part of the Salina thrust sheet. Also known as the West Falls Formation in New York. Geographic distribution The West Falls is recognized in the subsurface from western New York to eastern Tennessee. Lithology The predominant lithology of the West Falls Group is shale. The Rhinestreet Member can be further subdivided into two shale types: a thick, fissile black shale underlies a gray to greenish-gray shale that likely indicates a transi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Famennian
The Famennian is the later of two faunal stages in the Late Devonian epoch. The most recent estimate for its duration is that it lasted from around 371.1 to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commission on Stratigraphy, is that it lasted from million years ago to million years ago. It was preceded by the Frasnian stage and followed by the Tournaisian stage. Major events In the seas, a novel major group of ammonoid cephalopods called clymeniids appeared, underwent tremendous diversification and spread worldwide, then just as suddenly went extinct. The beginning of the Famennian is marked by the final stages of a major extinction event, the Kellwasser Event, which is the largest component of the Late Devonian mass extinction. The end of the Famennian experiences a smaller but still quite severe extinction event, the Hangenberg Event. A brief episode of glaciation, possibly linked to the Hangenberg event, occurred during the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Givetian
The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in France. The oldest forests occurred during the late Givetian. The lower GSSP A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. ... is located at Jebel Mech Irdane, Tafilalt, Morocco. Name and definition The Givetian Stage was proposed in 1879 by French geologist Jules Gosselet and was accepted for the higher stage of the Middle Devonian by the Subcommission on Devonian Stratigraphy in 1981. References Further reading * {{Geological history, p, p Middle Devonian Devonian geochronology . Devonian North America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmatolepis
''Palmatolepis'' is an extinct conodont genus in the family Palmatolepidae. It was the most abundant genus of conodonts of the Late Devonian, disappearing during the Devonian/Carboniferous crisis. Species * †''Palmatolepis glabra'' * †''Palmatolepis hassi''Locality and horizon: Upper part of the Grey Member, Ferques Formation, La Parisienne quarry (now flooded), Pas-de-Calais, France. Specimen from lowermost Ag. triangularis Conodont Zone, equivalent to late Palmatolepis hassi Zone (ca. 373 Ma, Frasnian). * †''Palmatolepis khaensis'' Savage 2013 * †''Palmatolepis marki'' Savage 2013 * †''Palmatolepis spallettae'' * †''Palmatolepis subperlobata'' ** †''Palmatolepis subperlobata lapoensis'' Savage 2013 * †''Palmatolepis triangularis'' * †''Palmatolepis unicornis'' Use in stratigraphy The Famennian (372.2 ± 1.6 mya) is defined by a GSSP Golden Spike located at Coumiac quarry, Montagne Noire, France where there is a biologic abundant occurrence of ''Palmato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jules Gosselet
Jules-Auguste Gosselet (19 April 1832 – 20 March 1916) was a French geologist born in Cambrai, France.Prix Gosselet - Société géologique de France (biography) Following unsuccessful studies of , and a stint as a teacher at the Lycée du Quesnoy, he pursued a career in . In 1853 he became a preparateur of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conodont
Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard, mineralised tooth-like structures called "conodont elements" that in life were present in the oral cavity and used to process food. Rare soft tissue remains suggest that they had elongate eel-like bodies with large eyes. Conodonts were a long-lasting group with over 300 million years of existence from the Cambrian (over 500 million years ago) to the beginning of the Jurassic (around 200 million years ago). Conodont elements are highly distinctive to particular species and are widely used in biostratigraphy as indicative of particular periods of geological time. Discovery and understanding of conodonts The teeth-like fossils of the conodont were first discovered by Heinz Christian Pander and the results published in Saint Petersburg, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coumiac Quarry
The Coumiac Formation is a geologic formation in France. It preserves fossils dated to the Devonian period. The Global Boundary Stratotype Section and Point (GSSP) for the base of the Famennian Stage of the Devonian is located at Coumiac quarry () near Cessenon-sur-Orb Cessenon-sur-Orb (, literally ''Cessenon on Orb (river), Orb''; ) is a Communes of France, commune in the Hérault Departments of France, department in southern France. Population See also *Communes of the Hérault department References .... See also * List of fossiliferous stratigraphic units in France References * Devonian France Devonian southern paleotemperate deposits {{Devonian-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the south and west by the Pacific Ocean. The region includes Middle America (Americas), Middle America (comprising the Caribbean, Central America, and Mexico) and Northern America. North America covers an area of about , representing approximately 16.5% of Earth's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa, and the list of continents and continental subregions by population, fourth-largest continent by population after Asia, Africa, and Europe. , North America's population was estimated as over 592 million people in list of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
