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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 large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti .... 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 * Wes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Geochronology
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Famennian
The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commission on Stratigraphy, estimated 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 Han ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genesee Group
The Genesee Group is a geologic formation in Pennsylvania. It preserves fossils dating back to the Devonian period. It includes submembers: * West River Shale * Genundewa Limestone * Penn Yan Formation * Geneseo Shale * North Evans Limestone North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' i ... See also * List of fossiliferous stratigraphic units in Pennsylvania * Paleontology in Pennsylvania References * * Geologic groups of Pennsylvania {{Pennsylvania-geologic-formation-stub ... [...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") Siltstone, Pulteney shale The Pulteney Shale is a geologic formation in New York. It preserves fossils dating back to the Devonian period. See also * List of fossiliferous stratigraphic units in New York This article contains a list of fossil-bearing stratigraphic uni ..., 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 geology of New York (state) {{Pennsylvania-geologic-formation- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Falls Group
Description Stratigraphy The West Falls Group is a geologic group in New York. It preserves fossils dating back to the Devonian period. 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. Geographic distribution The Rhinestreet Shale and Angola Shale Members of the West Falls Formation are both 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 transitional environment. The Angola member is a gray to greenish-gray shale, easily distinguished by its consistent low gamma ray signature, which is typical of this shale type. Paleontolog ... [...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 ''Palmatol ... [...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 is located at Jebel Mech Irdane Jabal, Jabel, Jebel or Jibal may refer to: People * Jabal (name), a male Arabic given name * Jabal (Bible), mentioned in the Hebrew Bible Places In Arabic, ''jabal'' or ''jebel'' (spelling variants of the same word) means 'mountain'. * Dzhebel, ..., 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 Givetian, Middle Devonian Devonian geochronology Devonian Europe, . Devonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conodont
Conodonts ( Greek ''kōnos'', " cone", + ''odont'', " tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which are usually found in isolation and are now called conodont elements. Knowledge about soft tissues remains limited. They existed in the world's oceans for over 300 million years, from the Cambrian to the beginning of the Jurassic. Conodont elements are widely used as index fossils, fossils used to define and identify geological periods. The animals are also called Conodontophora (conodont bearers) to avoid ambiguity. 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, Russia, in 1856. The name ''pander'' is commonly used in scientific names of conodonts. It was only in the early 1980s that the first fossil evi ... [...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 mathematics teacher at the Lycée du Quesnoy, he pursued a career in natural history. In 1853 he became a preparateur of |
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. See also * List of fossiliferous stratigraphic units in France See also * Lists of fossiliferous stratigraphic units in Europe References * {{DEFAULTSORT:Fossiliferous stratigraphic units in France * * France France geography-related lists ... References * Devonian France Devonian southern paleotemperate deposits {{Devonian-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
