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26-491: Rheic may refer to: Rheic Ocean , a Paleozoic ocean between the large continent Gondwana to the south and the microcontinents Avalonia and others Rheic acid , a synonym for the molecule rhein Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Rheic . If an internal link led you here, you may wish to change

52-578: A land mass, which has been named Gondwana (present day South America, Africa, Antarctica, Arabia , the Indian subcontinent , Zealandia and Australia), straddled the space between the South Pole and the Equator on one side of the globe. Off to the west were three other masses: Laurentia , Siberia and Baltica , located as if on the vertices of a triangle. To the south of them was a large archipelago,

78-746: A mid-oceanic ridge that separated small continental fragments such as Avalonia and Carolina from the main Gondwanan land mass, leading to the formation of the Rheic Ocean in the Early Ordovician. As Avalonia-Carolina drifted north from Gondwana, the Rheic Ocean grew and reached its maximum width (4,000 km (2,500 mi)) in the Silurian. In this process, the Iapetus Ocean closed as Avalonia-Carolina collided with Laurentia and

104-655: A rare green mineral first discovered in the Vogtland district of Saxony in Germany, which is in the Variscan belt, has the same etymology.) Hercynian , on the other hand, derives from the Hercynian Forest . Both words were descriptive terms of strike directions observed by geologists in the field, variscan for southwest to northeast, hercynian for northwest to southeast. The variscan direction reflected

130-611: A similar shift in meaning. Today, Hercynian is often used as a synonym for Variscan but is somewhat less used than the latter in the English speaking world. In the United States, it is used only for European orogenies; the contemporaneous and genetically linked mountain-building phases in the Appalachian Mountains have different names. The regional term Variscan underwent a further meaning shift since

156-695: A wide belt north of the Algarve and extending into the northernmost part the autonomous region of Andalusia and southern Extremadura . In the Czech Republic and southwestern Poland the Bohemian Massif is the eastern end of the unmodified Variscan belt of crustal deformation in Europe. Further Variscan developments to the southeast are partly hidden and overprinted by the Alpine orogeny . In

182-691: The Alps a Variscan core is built by Mercantour , Pelvoux , Belledonne , Montblanc and Aar Massif . Dinaric , Greek and Turkish mountain chains are the southeastern termination of the Variscan proper. The Variscan was contemporaneous with the Acadian and Alleghenian orogeny in the United States and Canada, responsible for forming the Ouachita and Appalachian Mountains . North American areas with Variscan foldbelts include New England , Nova Scotia and Newfoundland and Labrador . The Moroccan Meseta and

208-948: The Anti-Atlas in northwestern Africa show close relations to the Appalachian Mountains and used to form the eastern part of the Appalachian orogeny before the opening of the Atlantic Ocean in Jurassic times. 'Variscan' mountains in a broad chronological sense include the Urals , the Pamir , the Tian Shan and other Asian foldbelts. The Variscan orogeny involved a complicated heterogeneous assembly of different microplates and heterochronous collisions, making

234-709: The Appalachian orogeny formed. The closure of the Rheic began in the Early Devonian and was completed in the Mississippian when Gondwana and Laurentia collided to form Pangaea. This closure resulted in the largest collisional orogen of the Palaeozoic: the Variscan and Alleghanian orogens between Gondwana's West African margin and southern Baltica and eastern Laurentia and the Ouachita orogeny between

260-573: The Cadomian orogeny during the Ediacaran period. This orogeny formed a cordillera -type volcanic arc where oceanic crust subducted below Gondwana. When a mid-oceanic ridge subducted at an oblique angle, extensional basins developed along the northern margin of Gondwana. During the late Cambrian to Early Ordovician these extensional basins had evolved a rift running along the northern edge of Gondwana. The rift in its turn evolved into

286-535: The Rhine Massif (Ardennes, Eifel , Hunsrück , Taunus and other regions on both sides of Middle Rhine Valley), the Black Forest and Harz Mountains remain as testimony. In southern Iberia it is marked by a classic strike-slip suture zone between very distinct suspect terranes, and clear evidence can be seen of ductile shearing between high-grade metamorphic rocks and lower grade sedimentary rocks in

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312-764: The terrane Avalonia , rifted off the north Gondwana margin in early Ordovician . By the end of the Silurian and in Early Devonian times, Baltica and Laurentia drifted towards each other, closing the Iapetus Ocean between them. They collided in the Caledonian orogeny and formed the Caledonide mountains of North America, Greenland , the British Isles and Norway . Seafloor spreading to

338-556: The 1960s. Geologists generally began to use it to characterize late Paleozoic fold-belts and orogenic phases having an age of approximately 380 to 280 Ma. Some publications use the term Variscan for fold belts of even younger age, deviating from the meaning as a term for the North American and European orogeny related to the Gondwana-Laurasia collision. The North American and European Variscan Belt includes

364-565: The Amazonian margin of Gondwana and southern Laurentia. The Prague Basin, which was an archipelago of humid volcanic islands in the Rheic Ocean on the outer edges of what was then the Gondwanan shelf during the Silurian, was a major hotspot of plant biodiversity during the early stages of the Silurian-Devonian Terrestrial Revolution . The geologically rapid environmental changes associated with

390-707: The British Isles, northern Germany, Scandinavia and western Russia). In late Devonian and in the Carboniferous the archipelago Armorica of southern Europe, which had rifted off Gondwana after Avalonia later in the Ordovician, was pushed into Avalonia, creating a second range, the North American/European Variscan, to the east of the Caledonide/Appalachian. The collision of Gondwana proper with Laurussia followed in

416-756: The Early Cambrian was named for Iapetus , in Greek mythology the father of Atlas (from which source the Atlantic Ocean ultimately gets its name), just as the Iapetus Ocean was the predecessor of the Atlantic Ocean . The ocean between Gondwana and Laurussia ( Laurentia – Baltica – Avalonia ) that existed from the Early Ordovician to the Early Carboniferous was named the Rheic Ocean after Rhea , sister of Iapetus. At

442-471: The beginning of the Paleozoic Era, about 540 million years ago, most of the continental mass on Earth was clustered around the south pole as the paleocontinent Gondwana. The exception was formed by a number of smaller continents, such as Laurentia and Baltica . The Paleozoic ocean between Gondwana, Laurentia and Baltica is called the Iapetus Ocean . The northern edge of Gondwana had been dominated by

468-610: The direction of ancient fold belts cropping out throughout Germany and adjacent countries and the meaning shifted from direction to the fold belt proper. One of the pioneers in research on the Variscan fold belt was the German geologist Franz Kossmat , establishing a still valid division of the European Variscides in 1927. The other direction, Hercynian , for the direction of the Harz Mountains in Germany, saw

494-485: The early Carboniferous, when the Variscan belt was already in place and actively developing. By the end of the Carboniferous, Gondwana had united with Laurussia on its western end through northern South America and northwestern Africa. Siberia was approaching from the northeast, separated from Laurussia only by shallow waters. Collision with Siberia produced the Ural Mountains in the latest Paleozoic and completed

520-471: The exact reconstruction of the plate tectonic processes difficult. Plate convergence that caused the Caledonian orogeny in the Silurian continued to form the Variscan orogeny in the succeeding Devonian and Carboniferous Periods. Both orogenies resulted in the assembly of a super-continent, Pangaea , which was essentially complete by the end of the Carboniferous. In the Ordovician Period,

546-792: The formation and erosion of volcanic islands and high rates of endemism associated with island ecosystems likely played an important role in driving the rapid early diversification of vascular plants . It is believed that the closure of the Rheic, alongside the simultaneous onset of the Late Palaeozoic Ice Age , may have sparked the Carboniferous-Earliest Permian Biodiversification Event , an evolutionary radiation of marine life dominated by increase in species richness of fusulinids and brachiopods . Variscan orogeny The Variscan orogeny , or Hercynian orogeny ,

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572-947: The formation of Pangaea. Eastern Laurussia was still divided from Gondwana by the Paleotethys Ocean. In the Triassic Period of the Mesozoic Era, animals could move without oceanic impediment from Siberia over the North Pole to Antarctica over the South Pole. In the Mesozoic Era, rifting and subsequent opening of the Atlantic split Pangaea. As a consequence, the Variscan Belt around the then periphery of Baltica ended up many hundreds of miles from

598-409: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Rheic&oldid=556836470 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Rheic Ocean The ocean located between Gondwana and Laurentia in

624-913: The mountains of Portugal and Spain ( Galicia , and Pyrenees ), southwestern Ireland (i.e. Munster ), Cornwall , Devon , Pembrokeshire , the Gower Peninsula and the Vale of Glamorgan . Its effects are present in France from Brittany , below the Paris Basin to the Ardennes , the Massif Central , the Vosges and Corsica . The Variscan Belt reappears in Sardinia in Italy and in Germany where

650-587: The south of Avalonia pushed the latter into north Laurentia and thrust up the northern Appalachian Mountains in the acadian phase of the Caledonian orogeny. Contemporaneously the Tornquist Sea between Avalonia and Baltica was entirely closed. Thus Avalonia formed the southern coast of the new continent Euramerica ( Laurussia , the Old Red Sandstone continent in present-day North America,

676-599: Was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea . The name Variscan comes from the Medieval Latin name for the district Variscia , the home of a Germanic tribe, the Varisci ; Eduard Suess , professor of geology at the University of Vienna , coined the term in 1880. ( Variscite ,

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