The coastline of the North Sea has been evolving since the end of the last ice age . The coastline varies from fjords, river estuaries to mudflats.
134-491: The eastern and western coasts of the North Sea are jagged, as they were stripped by glaciers during the ice ages. The coastlines along the southernmost part are soft, covered with the remains of deposited glacial sediment, which was left directly by the ice or has been redeposited by the sea. The Norwegian mountains plunge into the sea, giving rise, north of Stavanger , to deep fjords and archipelagos . South of Stavanger,
268-630: A bolide impact, for which an impact crater containing Manicouagan Reservoir in Quebec , Canada , has been singled out. However, the Manicouagan impact melt has been dated to 214±1 Mya. The date of the Triassic-Jurassic boundary has also been more accurately fixed recently, at 201.4 Mya. Both dates are gaining accuracy by using more accurate forms of radiometric dating, in particular the decay of uranium to lead in zircons formed at time of
402-626: A cosmopolitan distribution . Coelacanths show their highest post- Devonian diversity in the Early Triassic . Ray-finned fishes (actinopterygians) went through a remarkable diversification in the beginning of the Triassic, leading to peak diversity during the Middle Triassic; however, the pattern of this diversification is still not well understood due to a taphonomic megabias . The first stem-group teleosts appeared during
536-651: A National Park. The whole of the coastal zone is shallow; the tides flood large areas and uncover them again, constantly depositing sediments. The Southern Bight has been especially changed by land reclamation, as the Dutch have been especially active. The largest project of this type was the diking and reclamation of the IJsselmeer . Tidal forces have formed the Frisian Islands . In the micro tidal area, (a tidal range of up to 1.35 meters (4.4 ft), such as on
670-571: A Tuath . The North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea because of its long coastline and the European rivers that empty it. There is little documentary evidence concerning the North Sea before the Roman conquest of Britain in 43 CE, however, archaeological evidence reveals the diffusion of cultures and technologies from across or along
804-555: A chain of mountain ranges stretching from Turkey to Malaysia . Pangaea was fractured by widespread faulting and rift basins during the Triassic—especially late in that period—but had not yet separated. The first nonmarine sediments in the rift that marks the initial break-up of Pangaea, which separated eastern North America from Morocco , are of Late Triassic age; in the United States , these thick sediments comprise
938-738: A challenge to their dominance of the North Sea until the 20th century. Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident . During the Russo-Japanese War , several ships of the Russian Baltic Fleet, which was on its way to the Far East, mistook British fishing boats for Japanese ships and fired on them, and then upon each other, near the Dogger Bank, nearly causing Britain to enter
1072-474: A few exposures in the west. During the Triassic peneplains are thought to have formed in what is now Norway and southern Sweden. Remnants of this peneplain can be traced as a tilted summit accordance in the Swedish West Coast . In northern Norway Triassic peneplains may have been buried in sediments to be then re-exposed as coastal plains called strandflats . Dating of illite clay from
1206-471: A long beak-like snout), and Shringasaurus (a horned herbivore which reached a body length of 3–4 metres (9.8–13.1 ft)). One group of archosauromorphs, the archosauriforms , were distinguished by their active predatory lifestyle, with serrated teeth and upright limb postures. Archosauriforms were diverse in the Triassic, including various terrestrial and semiaquatic predators of all shapes and sizes. The large-headed and robust erythrosuchids were among
1340-617: A pseudosuchian. Pseudosuchians were far more ecologically dominant in the Triassic, including large herbivores (such as aetosaurs ), large carnivores (" rauisuchians "), and the first crocodylomorphs (" sphenosuchians "). Aetosaurs were heavily-armored reptiles that were common during the last 30 million years of the Late Triassic until they died out at the Triassic-Jurassic extinction. Most aetosaurs were herbivorous and fed on low-growing plants, but some may have eaten meat. " rauisuchians " (formally known as paracrocodylomorphs ) were
1474-458: A short period of time, becoming extinct about 220 million years ago. They were exceptionally abundant in the middle of the Triassic, as the primary large herbivores in many Carnian-age ecosystems. They sheared plants with premaxillary beaks and plates along the upper jaw with multiple rows of teeth. Allokotosaurs were iguana-like reptiles, including Trilophosaurus (a common Late Triassic reptile with three-crowned teeth), Teraterpeton (which had
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#17327836911881608-449: A strandflat of Bømlo , southern Norway, have shown that landscape there became weathered in Late Triassic times ( c. 210 million years ago) with the landscape likely also being shaped during that time. Eustatic sea level in the Triassic was consistently low compared to the other geological periods. The beginning of the Triassic was around present sea level, rising to about 10–20 metres (33–66 ft) above present-day sea level during
1742-585: A supercontinent has less shoreline compared to a series of smaller continents, Triassic marine deposits are relatively uncommon on a global scale. A major exception is in Western Europe , where the Triassic was first studied. The northeastern margin of Gondwana was a stable passive margin along the Neo-Tethys Ocean, and marine sediments have been preserved in parts of northern India and Arabia . In North America , marine deposits are limited to
1876-665: A vast merchant marine, a large fishing fleet, powerful navy, and sophisticated financial markets made the Dutch the ascendant power in the North Sea, to be challenged by an ambitious England. This rivalry led to the first three Anglo-Dutch Wars between 1652 and 1673, which ended with Dutch victories. After the Glorious Revolution in 1688, the Dutch prince William ascended to the English throne. With unified leadership, commercial, military, and political power began to shift from Amsterdam to London. The British did not face
2010-472: A volume of 54,000 cubic kilometres (13,000 cu mi). Around the edges of the North Sea are sizeable islands and archipelagos , including Shetland , Orkney , and the Frisian Islands . The North Sea receives freshwater from a number of European continental watersheds, as well as the British Isles . A large part of the European drainage basin empties into the North Sea, including water from
2144-620: Is 17 °C (63 °F) in the summer and 6 °C (43 °F) in the winter. The average temperatures have been trending higher since 1988, which has been attributed to climate change . Air temperatures in January range on average between 0 and 4 °C (32 and 39 °F) and in July between 13 and 18 °C (55 and 64 °F). The winter months see frequent gales and storms. The salinity averages between 34 and 35 grams per litre (129 and 132 g/US gal) of water. The salinity has
2278-562: Is a major fishery . The coast is a popular destination for recreation and tourism in bordering countries, and a rich source of energy resources, including wind and wave power . The North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe , from the Middle Ages to the modern era. It was also important globally through the power northern Europeans projected worldwide during much of
2412-468: Is a recent study of North American faunas. In the Petrified Forest of northeast Arizona there is a unique sequence of late Carnian-early Norian terrestrial sediments. An analysis in 2002 found no significant change in the paleoenvironment. Phytosaurs , the most common fossils there, experienced a change-over only at the genus level, and the number of species remained the same. Some aetosaurs ,
2546-466: Is a series of asymmetrical trenches between 20 and 30 kilometres (12 and 19 mi) long, one and two kilometres (0.6 and 1.2 mi) wide and up to 230 metres (750 ft) deep. Other areas which are less deep are Cleaver Bank , Fisher Bank and Noordhinder Bank . The International Hydrographic Organization defines the limits of the North Sea as follows: On the Southwest. A line joining
2680-526: Is also home to marine mammals. Common seals , grey seals , and harbour porpoises can be found along the coasts, at marine installations, and on islands. The very northern North Sea islands such as the Shetland Islands are occasionally home to a larger variety of pinnipeds including bearded , harp , hooded and ringed seals , and even walrus . North Sea cetaceans include various porpoise , dolphin and whale species. Plant species in
2814-780: Is bounded by the Orkney Islands and east coast of Great Britain to the west and the northern and central European mainland to the east and south, including Norway , Denmark , Germany , the Netherlands , Belgium , and France . In the southwest, beyond the Straits of Dover , the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via
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#17327836911882948-508: Is likely a paraphyletic group rather than a true clade. Tanystropheids were a family of protorosaurs which elevated their neck size to extremes, with the largest genus Tanystropheus having a neck longer than its body. The protorosaur family Sharovipterygidae used their elongated hindlimbs for gliding. Other archosauromorphs, such as rhynchosaurs and allokotosaurs , were mostly stocky-bodied herbivores with specialized jaw structures. Rhynchosaurs, barrel-gutted herbivores, thrived for only
3082-466: Is low and marshy. The east coast and south-east of the North Sea ( Wadden Sea ) have coastlines that are mainly sandy and straight owing to longshore currents , particularly along Belgium and Denmark. The northern North Sea coasts bear the impression of the enormous glaciers which covered them during the Ice Ages and created fjords, lakes and valleys along the coastline and landscape. Fjords arose by
3216-469: Is no evidence of glaciation at or near either pole; in fact, the polar regions were apparently moist and temperate , providing a climate suitable for forests and vertebrates, including reptiles. Pangaea's large size limited the moderating effect of the global ocean; its continental climate was highly seasonal, with very hot summers and cold winters. The strong contrast between the Pangea supercontinent and
3350-643: Is recorded to have killed more than 100,000 people. In 1362, the Second Marcellus Flood , also known as the Grote Manndrenke , hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths, large parts of the coast were lost permanently to the sea, including the now legendary lost city of Rungholt . In the 20th century, the North Sea flood of 1953 flooded several nations' coasts and cost more than 2,000 lives. 315 citizens of Hamburg died in
3484-460: Is superimposed by 22 sea level drop events widespread in the geologic record, mostly of minor (less than 25-metre (82 ft)) and medium (25–75-metre (82–246 ft)) magnitudes. A lack of evidence for Triassic continental ice sheets suggest that glacial eustasy is unlikely to be the cause of these changes. The Triassic continental interior climate was generally hot and dry, so that typical deposits are red bed sandstones and evaporites . There
3618-536: Is the Norwegian trench , which extends parallel to the Norwegian shoreline from Oslo to an area north of Bergen . It is between 20 and 30 kilometres (12 and 19 mi) wide and has a maximum depth of 725 metres (2,379 ft). The Dogger Bank , a vast moraine , or accumulation of unconsolidated glacial debris, rises to a mere 15 to 30 m (50 to 100 ft) below the surface. This feature has produced
3752-653: Is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon . Both the start and end of the period are marked by major extinction events . The Triassic Period is subdivided into three epochs: Early Triassic , Middle Triassic and Late Triassic . The Triassic began in the wake of the Permian–Triassic extinction event , which left the Earth's biosphere impoverished; it
3886-518: The Baltic Sea . The largest and most important rivers flowing into the North Sea are the Elbe and the Rhine – Meuse . Around 185 million people live in the catchment area of the rivers discharging into the North Sea encompassing some highly industrialized areas. For the most part, the sea lies on the European continental shelf with a mean depth of 90 metres (300 ft). The only exception
4020-525: The Battle of Heligoland Bight , the Battle of the Dogger Bank , and the Battle of Jutland . World War I also brought the first extensive use of submarine warfare , and a number of submarine actions occurred in the North Sea. The Second World War also saw action in the North Sea, though it was restricted more to aircraft reconnaissance and action by fighter/bomber aircraft, submarines and smaller vessels such as minesweepers and torpedo boats . After
4154-578: The Carnian (early part of the Late Triassic), some advanced cynodonts gave rise to the first mammals . During the Triassic, archosaurs displaced therapsids as the largest and most ecologically prolific terrestrial amniotes. This "Triassic Takeover" may have contributed to the evolution of mammals by forcing the surviving therapsids and their mammaliaform successors to live as small, mainly nocturnal insectivores . Nocturnal life may have forced
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4288-528: The English Channel was triggered by the earthquake, which in turn caused a tsunami. The tsunami triggered by the 1755 Lisbon earthquake reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the 1931 Dogger Bank earthquake , which measured 6.1 on the Richter magnitude scale and caused a small tsunami that flooded parts of
4422-614: The Jurassic , when the temnospondyls had become very rare. Most of the Reptiliomorpha , stem-amniotes that gave rise to the amniotes, disappeared in the Triassic, but two water-dwelling groups survived: Embolomeri that only survived into the early part of the period, and the Chroniosuchia , which survived until the end of the Triassic. The Permian–Triassic extinction devastated terrestrial life. Biodiversity rebounded as
4556-568: The Lake Lugano region of northern Italy and southern Switzerland , was in Middle Triassic times a lagoon behind reefs with an anoxic bottom layer, so there were no scavengers and little turbulence to disturb fossilization, a situation that can be compared to the better-known Jurassic Solnhofen Limestone lagerstätte . The remains of fish and various marine reptiles (including the common pachypleurosaur Neusticosaurus , and
4690-517: The Last Glacial Maximum when the sea began to flood the European continental shelf. In 2006 a bone fragment was found while drilling for oil in the North Sea. Analysis indicated that it was a Plateosaurus from 199 to 216 million years ago. This was the deepest dinosaur fossil ever found and the first find for Norway. Copepods and other zooplankton are plentiful in the North Sea. These tiny organisms are crucial elements of
4824-965: The Latin names Mare Germanicum and Oceanus Germanicus , and these persisted in use until the First World War. Other common names in use for long periods were the Latin terms Mare Frisicum , as well as the English equivalent, "Frisian Sea". The modern names of the sea in the other local languages are: Danish : Vesterhavet , lit. 'West Sea' [ˈvestɐˌhɛˀvð̩] or Nordsøen [ˈnoɐ̯ˌsøˀn̩] , Dutch : Noordzee , Dutch Low Saxon : Noordzee , French : Mer du Nord , West Frisian : Noardsee , German : Nordsee , Low German : Noordsee , North Frisian : Weestsiie , lit. 'West Sea', Swedish : Nordsjön , Bokmål : Nordsjøen [ˈnûːrˌʂøːn] , Nynorsk : Nordsjøen , Scots : North Sea and Scottish Gaelic : An Cuan
4958-595: The Netherlands , Belgium and France . An epeiric sea on the European continental shelf , it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, covering 570,000 square kilometres (220,000 sq mi). It hosts key north European shipping lanes and
5092-658: The Newark Supergroup . Rift basins are also common in South America, Europe, and Africa. Terrestrial environments are particularly well-represented in the South Africa, Russia, central Europe, and the southwest United States. Terrestrial Triassic biostratigraphy is mostly based on terrestrial and freshwater tetrapods, as well as conchostracans ("clam shrimps"), a type of fast-breeding crustacean which lived in lakes and hypersaline environments. Because
5226-472: The North Sea flood of 1962 . Though rare, the North Sea has been the site of a number of historically documented tsunamis . The Storegga Slides were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BCE and 6000 BCE, and caused a tsunami up to 20 metres (66 ft) high that swept through
5360-474: The Olenekian and Anisian of Gondwana . Both kannemeyeriiform dicynodonts and gomphodont cynodonts remained important herbivores during much of the period. Therocephalians included both large predators ( Moschorhinus ) and herbivorous forms ( bauriids ) until their extinction midway through the period. Ecteniniid cynodonts played a role as large-sized, cursorial predators in the Late Triassic. During
5494-1016: The Phare de Walde (Walde Lighthouse, in France, 50°59'37"N, 1°54'53"E) and Leathercoat Point (England, 51°10'01.4"N 1°24'07.8"). northeast of Dover. On the Northwest. From Dunnet Head (58°40'20"N, 3°22'30"W) in Scotland to Tor Ness (58°47'N) in the Island of Hoy , thence through this island to the Kame of Hoy (58°55'N) on to Breck Ness on Mainland (58°58'N) through this island to Costa Head (3°14'W) and Inga Ness (59'17'N) in Westray through Westray, to Bow Head, across to Mull Head (North point of Papa Westray ) and on to Seal Skerry (North point of North Ronaldsay ) and thence to Horse Island (South point of
Coastline of the North Sea - Misplaced Pages Continue
5628-826: The Shetland Islands). On the North. From the North point (Fethaland Point) of the Mainland of the Shetland Islands, across to Graveland Ness (60°39'N) in the Island of Yell , through Yell to Gloup Ness (1°04'W) and across to Spoo Ness (60°45'N) in Unst island, through Unst to Herma Ness (60°51'N), on to the SW point of the Rumblings and to Muckle Flugga ( 60°51′N 0°53′W / 60.850°N 0.883°W / 60.850; -0.883 ) all these being included in
5762-608: The Skagerrak and Kattegat , narrow straits that separate Denmark from Norway and Sweden respectively. In the north it is bordered by the Shetland Islands , and connects with the Norwegian Sea , which is a marginal sea in the Arctic Ocean . The North Sea is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, with an area of 750,000 square kilometres (290,000 sq mi) and
5896-463: The food chain supporting many species of fish. Over 230 species of fish live in the North Sea. Cod , haddock , whiting , saithe , plaice , sole , mackerel , herring , pouting , sprat , and sandeel are all very common and are fished commercially. Due to the various depths of the North Sea trenches and differences in salinity, temperature, and water movement, some fish such as blue-mouth redfish and rabbitfish reside only in small areas of
6030-535: The littoral is low and marshy. The east coast and south-east of the North Sea ( Wadden Sea ) have coastlines that are mainly sandy and straight owing to longshore drift , particularly along Belgium and Denmark. The southern coastal areas were originally flood plains and swampy land. In areas especially vulnerable to storm surges, people settled behind elevated levees and on natural areas of high ground such as spits and geestland . As early as 500 BC, people were constructing artificial dwelling hills higher than
6164-735: The surviving species repopulated empty terrain, but these were short-lived. Diverse communities with complex food-web structures took 30 million years to reestablish. Archosauromorph reptiles, which had already appeared and diversified to an extent in the Permian Period, exploded in diversity as an adaptive radiation in response to the Permian-Triassic mass extinction. By the Early Triassic, several major archosauromorph groups had appeared. Long-necked, lizard-like early archosauromorphs were known as protorosaurs , which
6298-463: The temnospondyls , giant aquatic predators that had survived the end-Permian extinction and saw a new burst of diversification in the Triassic, before going extinct by the end; however, early crown-group lissamphibians (including stem-group frogs , salamanders and caecilians ) also became more common during the Triassic and survived the extinction event. The earliest known neopterygian fish, including early holosteans and teleosts , appeared near
6432-524: The thecodonts ) disappeared, as did most of the large labyrinthodont amphibians, groups of small reptiles, and most synapsids. Some of the early, primitive dinosaurs also became extinct, but more adaptive ones survived to evolve into the Jurassic. Surviving plants that went on to dominate the Mesozoic world included modern conifers and cycadeoids. The cause of the Late Triassic extinction is uncertain. It
6566-437: The traversodont cynodonts—were much reduced in the northern half of Pangaea ( Laurasia ). These extinctions within the Triassic and at its end allowed the dinosaurs to expand into many niches that had become unoccupied. Dinosaurs became increasingly dominant, abundant and diverse, and remained that way for the next 150 million years. The true "Age of Dinosaurs" is during the following Jurassic and Cretaceous periods, rather than
6700-741: The 13th century the Hanseatic League , though centred on the Baltic Sea , started to control most of the trade through important members and outposts on the North Sea. The League lost its dominance in the 16th century, as neighbouring states took control of former Hanseatic cities and outposts. Their internal conflict prevented effective cooperation and defence. As the League lost control of its maritime cities, new trade routes emerged that provided Europe with Asian, American, and African goods. The 17th century Dutch Golden Age saw Dutch maritime power at its zenith. Important overseas colonies,
6834-832: The Anisian to Ladinian of the Tethysian domain, and from the Carnian and Rhaetian of a larger area that includes also the Boreal domain (e.g., Svalbard Islands), the North American continent, the South China block and Argentina . The best-studied of such episodes of humid climate, and probably the most intense and widespread, was the Carnian Pluvial Event . The Early Triassic was the hottest portion of
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#17327836911886968-410: The British coast. Shallow epicontinental seas like the current North Sea have since long existed on the European continental shelf . The rifting that formed the northern part of the Atlantic Ocean during the Jurassic and Cretaceous periods, from about 150 million years ago , caused tectonic uplift in the British Isles. Since then, a shallow sea has almost continuously existed between
7102-405: The Carnian and include early sauropodomorphs and theropods. Most Triassic dinosaurs were small predators and only a few were common, such as Coelophysis , which was 1 to 2 metres (3.3 to 6.6 ft) long. Triassic sauropodomorphs primarily inhabited cooler regions of the world. The large predator Smok was most likely also an archosaur, but it is uncertain if it was a primitive dinosaur or
7236-400: The Dutch or Danish coasts, barrier beaches with dunes are formed. In the mesotidal area (a tidal range of between 1.35 and 2.9 m (4.4 and 9.5 ft)), barrier islands are formed; in the macrotidal area (above 2.9 meters (9.5 ft) tidal range), intertidal deposits raise the spring tide range 4 meters (13 ft). A soft rock coast is formed in the meso-macro tidal areas located in
7370-448: The Early Triassic, forming small patches of reefs of modest extent compared to the great reef systems of Devonian or modern times. At the end of the Carnian, a reef crisis occurred in South China. Serpulids appeared in the Middle Triassic. Microconchids were abundant. The shelled cephalopods called ammonites recovered, diversifying from a single line that survived the Permian extinction. Bivalves began to rapidly diversify during
7504-402: The Early Triassic, while others (e.g. capitosaurs ) remained successful throughout the whole period, or only came to prominence in the Late Triassic (e.g. Plagiosaurus , metoposaurs ). The first Lissamphibians (modern amphibians) appear in the Triassic, with the progenitors of the first frogs already present by the Early Triassic. However, the group as a whole did not become common until
7638-401: The Early and Middle Triassic. Sea level rise accelerated in the Ladinian, culminating with a sea level up to 50 metres (164 ft) above present-day levels during the Carnian. Sea level began to decline in the Norian, reaching a low of 50 metres (164 ft) below present sea level during the mid-Rhaetian. Low global sea levels persisted into the earliest Jurassic. The long-term sea level trend
7772-490: The Humber and the Thames. There are skerries in southern Norway formed by similar action to that which created the fjords and firths. The glaciers in these places affected the land to an even greater extent, so that large areas were scraped away. The coastal brim ( Strandflaten ), which is found especially in southern Norway, is a gently sloping lowland area between the sea and the mountains. It consists of plates of rock platforms, and often extends for kilometres, reaching under
7906-499: The Jurassic. There were many types of marine reptiles. These included the Sauropterygia , which featured pachypleurosaurus and nothosaurs (both common during the Middle Triassic, especially in the Tethys region), placodonts , the earliest known herbivorous marine reptile Atopodentatus , and the first plesiosaurs . The first of the lizardlike Thalattosauria ( askeptosaurs ) and the highly successful ichthyopterygians , which appeared in Early Triassic seas, soon diversified. By
8040-432: The Late Triassic but did not become dominant until the succeeding Jurassic Period. Archosaurs that became dominant in this period were primarily pseudosuchians , relatives and ancestors of modern crocodilians , while some archosaurs specialized in flight, the first time among vertebrates, becoming the pterosaurs . Therapsids , the dominant vertebrates of the preceding Permian period, saw a brief surge in diversification in
8174-446: The Latest Olenekian Cooling (LOC), from 248 to 247 Ma, temperatures cooled by about 6 °C. The Middle Triassic was cooler than the Early Triassic, with temperatures falling over most of the Anisian, with the exception of a warming spike in the latter portion of the stage. From 242 to 233 Ma, the Ladinian-Carnian Cooling (LCC) ensued. At the beginning of the Carnian, global temperatures continued to be relatively cool. The eruption of
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#17327836911888308-407: The Middle Ages and into the modern era. The North Sea was the centre of the Vikings' rise . The Hanseatic League , the Dutch Republic , and the British each sought to gain command of the North Sea and access to the world's markets and resources. As Germany's only outlet to the ocean, the North Sea was strategically important through both world wars. The coast has diverse geology and geography. In
8442-445: The Middle Ages through the 15th century, the northern European coastal ports exported domestic goods, dyes, linen, salt, metal goods and wine. The Scandinavian and Baltic areas shipped grain, fish, naval necessities, and timber. In turn, the North Sea countries imported high-grade cloths, spices, and fruits from the Mediterranean region. Commerce during this era was mainly conducted by maritime trade due to underdeveloped roadways. In
8576-420: The Middle Triassic, becoming highly abundant in the oceans. Aquatic insects rapidly diversified during the Middle Triassic, with this time interval representing a crucial diversification for Holometabola , the clade containing the majority of modern insect species. In the wake of the Permian-Triassic mass extinction event , the fish fauna was remarkably uniform, with many families and genera exhibiting
8710-428: The Middle Triassic, some ichthyopterygians were achieving very large body masses. Among other reptiles, the earliest turtles , like Proganochelys and Proterochersis , appeared during the Norian Age (Stage) of the Late Triassic Period. The Lepidosauromorpha , specifically the Sphenodontia , are first found in the fossil record of the earlier Carnian Age, though the earliest lepidosauromorphs likely occurred in
8844-426: The Netherlands. The North Sea Floods of 1953 and 1962 were the impetus for further raising of the dikes as well as the shortening of the coast line so as to present as little surface area as possible to the punishment of the sea and the storms. Currently, 27% of the Netherlands is below sea level protected by dikes, dunes, and beach flats. Coastal management today consists of several levels. The dike slope reduces
8978-683: The North Sea are home to nature reserves including the Ythan Estuary , Fowlsheugh Nature Preserve, and Farne Islands in the UK and the Wadden Sea National Parks in Denmark, Germany and the Netherlands. These locations provide breeding habitat for dozens of bird species. Tens of millions of birds make use of the North Sea for breeding, feeding, or migratory stopovers every year. Populations of black-legged kittiwakes , Atlantic puffins , northern gannets , northern fulmars , and species of petrels , seaducks , loons (divers), cormorants , gulls , auks , and terns , and many other seabirds make these coasts popular for birdwatching . The North Sea
9112-516: The North Sea area; thence up the meridian of 0°53' West to the parallel of 61°00' North and eastward along this parallel to the coast of Norway, the whole of Viking Bank is thus included in the North Sea. On the East. The Western limit of the Skagerrak [A line joining Hanstholm ( 57°07′N 8°36′E / 57.117°N 8.600°E / 57.117; 8.600 ) and the Naze ( Lindesnes , 58°N 7°E / 58°N 7°E / 58; 7 )]. The average temperature
9246-402: The North Sea during the Migration Period . They made successive invasions of the island from what is now the Netherlands, Denmark, and Germany. The Viking Age began in 793 with the attack on Lindisfarne ; for the next quarter-millennium, the Vikings ruled the North Sea. In their superior longships , they raided, traded, and established colonies and outposts along the coasts of the sea. From
9380-554: The North Sea include species of wrack , among them bladder wrack , knotted wrack , and serrated wrack. Algae , macroalgal, and kelp , such as oarweed and laminaria hyperboria, and species of maerl are found as well. Eelgrass , formerly common in the entirety of the Wadden Sea, was nearly wiped out in the 20th century by a disease. Similarly, sea grass used to coat huge tracts of ocean floor, but have been damaged by trawling and dredging have diminished its habitat and prevented its return. Invasive Japanese seaweed has spread along
9514-445: The North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on the North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade the diffusion of cultures and technologies from across or along the North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on
9648-416: The North Sea until the 20th century, when numbers declined due to overfishing . Other factors like the introduction of non-indigenous species , industrial and agricultural pollution , trawling and dredging , human-induced eutrophication , construction on coastal breeding and feeding grounds, sand and gravel extraction, offshore construction , and heavy shipping traffic have also contributed to
9782-590: The North Sea, having the greatest effect on Scotland and the Faeroe Islands . The Dover Straits earthquake of 1580 is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter scale. This event caused extensive damage in Calais both through its tremors and possibly triggered a tsunami , though this has never been confirmed. The theory is a vast underwater landslide in
9916-453: The North Sea. Crustaceans are also commonly found throughout the sea. Norway lobster , deep-water prawns , and brown shrimp are all commercially fished, but other species of lobster , shrimp , oyster , mussels and clams all live in the North Sea. Recently non-indigenous species have become established including the Pacific oyster and Atlantic jackknife clam . The coasts of
10050-572: The North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade and many Scandinavian tribes participated in raids and wars against the Romans and Roman coinage and manufacturing were important trade goods. When the Romans abandoned Britain in 410, the Germanic Angles , Frisians , Saxons , and Jutes began the next great migration across
10184-500: The North Sea. The wave continues to travel northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the Kelvin wave turns east and south and once again enters the North Sea. The eastern and western coasts of the North Sea are jagged, formed by glaciers during the ice ages . The coastlines along the southernmost part are covered with the remains of deposited glacial sediment. The Norwegian mountains plunge into
10318-558: The Orkney Islands through the mid-16th century, as both Sable Island and Orkney Islands lay within their normal range. Grey whales also resided in the North Sea but were driven to extinction in the Atlantic in the 17th century Other species have dramatically declined in population, though they are still found. North Atlantic right whales , sturgeon , shad , rays , skates , salmon , and other species were common in
10452-505: The Permian extinction, Archaeplastida (red and green algae) had been the major marine phytoplanktons since about 659–645 million years ago, when they replaced marine planktonic cyanobacteria , which first appeared about 800 million years ago, as the dominant phytoplankton in the oceans. In the Triassic, secondary endosymbiotic algae became the most important plankton. In marine environments , new modern types of corals appeared in
10586-475: The Permian. The Procolophonidae , the last surviving parareptiles , were an important group of small lizard-like herbivores. The drepanosaurs were a clade of unusual, chameleon-like arboreal reptiles with birdlike heads and specialised claws. Three therapsid groups survived into the Triassic: dicynodonts , therocephalians , and cynodonts . The cynodont Cynognathus was a characteristic top predator in
10720-553: The Scottish coast. Individual islands in the firths, or islands and the coast, are often joined up by sandbars or spits made up of sand deposits known as " tombolos ". Towards the south the firths give way to a cliff coast, which was formed by the moraines of Ice Age glaciers. The horizontal impact of waves on the North Sea coast gives rise to eroded coasts. The cliff landscape is interrupted in southern England by large estuaries with their corresponding fringing marshes, notably
10854-408: The Triassic (teleosts are by far the most diverse group of fish today). Predatory actinopterygians such as saurichthyids and birgeriids , some of which grew over 1.2 m (3.9 ft) in length, appeared in the Early Triassic and became widespread and successful during the period as a whole. Lakes and rivers were populated by lungfish (Dipnoi), such as Ceratodus , which are mainly known from
10988-476: The Triassic was mostly hot and dry, with deserts spanning much of Pangaea's interior. However, the climate shifted and became more humid as Pangaea began to drift apart. The end of the period was marked by yet another major mass extinction, the Triassic–Jurassic extinction event , that wiped out many groups, including most pseudosuchians, and allowed dinosaurs to assume dominance in the Jurassic. The Triassic
11122-609: The Triassic, enlarging the Neo-Tethys Ocean which formed in their wake. At the same time, they forced the Paleo-Tethys Ocean to shrink as it was being subducted under Asia. By the end of the Triassic, the Paleo-Tethys Ocean occupied a small area and the Cimmerian terranes began to collide with southern Asia. This collision, known as the Cimmerian Orogeny , continued into the Jurassic and Cretaceous to produce
11256-428: The Triassic, with dicynodonts and cynodonts quickly becoming dominant, but they declined throughout the period with the majority becoming extinct by the end. However, the first stem-group mammals ( mammaliamorphs ), themselves a specialized subgroup of cynodonts, appeared during the Triassic and would survive the extinction event, allowing them to radiate during the Jurassic. Amphibians were primarily represented by
11390-839: The Wrangellia Large Igneous Province around 234 Ma caused abrupt global warming, terminating the cooling trend of the LCC. This warming was responsible for the Carnian Pluvial Event and resulted in an episode of widespread global humidity. The CPE ushered in the Mid-Carnian Warm Interval (MCWI), which lasted from 234 to 227 Ma. At the Carnian-Norian boundary occurred a positive δ C excursion believed to signify an increase in organic carbon burial. From 227 to 217 Ma, there
11524-427: The action of glaciers, which dragged their way through them from the highlands, cutting and scraping deep trenches in the land. Fjords are particularly common on the coast of Norway. Firths are similar to fjords, but are generally shallower with broader bays in which small islands may be found. The glaciers that formed them influenced the land over a wider area and scraped away larger areas. Firths are to be found on
11658-415: The beginning of the Triassic, and quickly diversified to become among the dominant groups of fish in both freshwater and marine habitats. The vast supercontinent of Pangaea dominated the globe during the Triassic, but in the latest Triassic ( Rhaetian ) and Early Jurassic it began to gradually rift into two separate landmasses: Laurasia to the north and Gondwana to the south. The global climate during
11792-455: The bizarre long-necked archosauromorph Tanystropheus ), along with some terrestrial forms like Ticinosuchus and Macrocnemus , have been recovered from this locality. All these fossils date from the Anisian and Ladinian ages (about 242 Ma ago). The Triassic Period ended with a mass extinction, which was particularly severe in the oceans; the conodonts disappeared, as did all
11926-464: The coast softens, the islands become fewer. The eastern Scottish coast is similar, though less severe than Norway. Starting from Flamborough Head in the north east of England, the cliffs become lower and are composed of less resistant moraine , which erodes more easily, so that the coasts have more rounded contours. In the Netherlands, Belgium and in the east of England ( East Anglia ) the littoral
12060-551: The coasts of the Netherlands, Belgium, Germany, and Denmark and low-lying areas of eastern England particularly around The Wash and Fens . Storm surges are caused by changes in barometric pressure combined with strong wind created wave action . The first recorded storm tide flood was the Julianenflut , on 17 February 1164. In its wake, the Jadebusen , (a bay on the coast of Germany), began to form. A storm tide in 1228
12194-412: The corresponding rocks are referred to as Lower, Middle, or Upper Triassic. The faunal stages from the youngest to oldest are: During the Triassic, almost all the Earth's land mass was concentrated into a single supercontinent , Pangaea ( lit. ' entire land ' ). This supercontinent was more-or-less centered on the equator and extended between the poles, though it did drift northwards as
12328-586: The decline. For example, a resident orca pod was lost in the 1960s, presumably due to the peak in PCB pollution in this time period. The OSPAR commission manages the OSPAR convention to counteract the harmful effects of human activity on wildlife in the North Sea, preserve endangered species , and provide environmental protection. All North Sea border states are signatories of the MARPOL 73/78 Accords, which preserve
12462-506: The dental plates, abundant in the fossils record. Hybodonts , a group of shark-like cartilaginous fish , were dominant in both freshwater and marine environments throughout the Triassic. Last survivors of the mainly Palaeozoic Eugeneodontida are known from the Early Triassic. Temnospondyl amphibians were among those groups that survived the Permian–Triassic extinction. Once abundant in both terrestrial and aquatic environments,
12596-428: The dominant carnivores in the early Triassic. Phytosaurs were a particularly common group which prospered during the Late Triassic. These long-snouted and semiaquatic predators resemble living crocodiles and probably had a similar lifestyle, hunting for fish and small reptiles around the water's edge. However, this resemblance is only superficial and is a prime-case of convergent evolution. True archosaurs appeared in
12730-458: The early Triassic, splitting into two branches: Avemetatarsalia (the ancestors to birds) and Pseudosuchia (the ancestors to crocodilians). Avemetatarsalians were a minor component of their ecosystems, but eventually produced the earliest pterosaurs and dinosaurs in the Late Triassic. Early long-tailed pterosaurs appeared in the Norian and quickly spread worldwide. Triassic dinosaurs evolved in
12864-555: The energy of the incoming sea, so that the dike itself does not receive the full impact. Dikes that lie directly on the sea are especially reinforced. The dikes have, over the years, been repeatedly raised, sometimes up to 9 metres (30 ft) and have been made flatter to better reduce wave erosion. Where the dunes are sufficient to protect the land behind them from the sea, these dunes are planted with beach grass ( Ammophila arenaria ) to protect them from erosion by wind, water, and foot traffic. Storm surges threaten, in particular,
12998-640: The entire Phanerozoic, seeing as it occurred during and immediately after the discharge of titanic volumes of greenhouse gases from the Siberian Traps. The Early Triassic began with the Permian-Triassic Thermal Maximum (PTTM) and was followed by the brief Dienerian Cooling (DC) from 251 to 249 Ma, which was in turn followed by the Latest Smithian Thermal Maximum (LSTT) around 249 to 248 Ma. During
13132-480: The extinct family Cheirolepidiaceae , which first appeared in the Late Triassic, and would be prominent throughout most of the rest of the Mesozoic. No known coal deposits date from the start of the Triassic Period. This is known as the Early Triassic "coal gap" and can be seen as part of the Permian–Triassic extinction event . Possible explanations for the coal gap include sharp drops in sea level at
13266-572: The finest fishing location of the North Sea. The Long Forties and the Broad Fourteens are large areas with roughly uniform depth in fathoms (forty fathoms and fourteen fathoms or 73 and 26 m or 240 and 85 ft deep, respectively). These great banks and others make the North Sea particularly hazardous to navigate, which has been alleviated by the implementation of satellite navigation systems . The Devil's Hole lies 320 kilometres (200 mi) east of Dundee , Scotland. The feature
13400-521: The global ocean triggered intense cross-equatorial monsoons , sometimes referred to as the Pangean megamonsoons . The Triassic may have mostly been a dry period, but evidence exists that it was punctuated by several episodes of increased rainfall in tropical and subtropical latitudes of the Tethys Sea and its surrounding land. Sediments and fossils suggestive of a more humid climate are known from
13534-531: The highest variability where there is fresh water inflow, such as at the Rhine and Elbe estuaries, the Baltic Sea exit and along the coast of Norway. The main pattern to the flow of water in the North Sea is an anti-clockwise rotation along the edges. The North Sea is an arm of the Atlantic Ocean receiving the majority of ocean current from the northwest opening, and a lesser portion of warm current from
13668-420: The impact. So, the evidence suggests the Manicouagan impact preceded the end of the Triassic by approximately 10±2 Ma. It could not therefore be the immediate cause of the observed mass extinction. The number of Late Triassic extinctions is disputed. Some studies suggest that there are at least two periods of extinction towards the end of the Triassic, separated by 12 to 17 million years. But arguing against this
13802-401: The keystone predators of most Triassic terrestrial ecosystems. Over 25 species have been found, including giant quadrupedal hunters, sleek bipedal omnivores, and lumbering beasts with deep sails on their backs. They probably occupied the large-predator niche later filled by theropods. "Rauisuchians" were ancestral to small, lightly-built crocodylomorphs, the only pseudosuchians which survived into
13936-611: The mammaliaforms to develop fur and a higher metabolic rate . Two Early Triassic lagerstätten (high-quality fossil beds), the Dienerian aged Guiyang biota and the earliest Spathian aged Paris biota stand out due to their exceptional preservation and diversity . They represent the earliest lagerstätten of the Mesozoic era and provide insight into the biotic recovery from the Permian-Triassic mass extinction event. The Monte San Giorgio lagerstätte, now in
14070-489: The marine environment by preventing pollution from ships. Germany, Denmark, and the Netherlands also have a trilateral agreement for the protection of the Wadden Sea , or mudflats , which run along the coasts of the three countries on the southern edge of the North Sea. The North Sea has had various names throughout history. One of the earliest recorded names was Septentrionalis Oceanus , or "Northern Ocean", which
14204-453: The marine reptiles except ichthyosaurs and plesiosaurs . Invertebrates like brachiopods and molluscs (such as gastropods ) were severely affected. In the oceans, 22% of marine families and possibly about half of marine genera went missing. Though the end-Triassic extinction event was not equally devastating in all terrestrial ecosystems, several important clades of crurotarsans (large archosaurian reptiles previously grouped together as
14338-458: The modern Pacific Ocean . Practically all deep-ocean crust present during the Triassic has been recycled through the subduction of oceanic plates, so very little is known about the open ocean from this time period. Most information on Panthalassan geology and marine life is derived from island arcs and rare seafloor sediments accreted onto surrounding land masses, such as present-day Japan and western North America. The eastern edge of Pangea
14472-430: The next most common tetrapods, and early dinosaurs, passed through unchanged. However, both phytosaurs and aetosaurs were among the groups of archosaur reptiles completely wiped out by the end-Triassic extinction event. It seems likely then that there was some sort of end-Carnian extinction, when several herbivorous archosauromorph groups died out, while the large herbivorous therapsids —the kannemeyeriid dicynodonts and
14606-679: The north, deep fjords and sheer cliffs mark much of its Norwegian and Scottish coastlines respectively, whereas in the south, the coast consists mainly of sandy beaches, estuaries of long rivers and wide mudflats . Due to the dense population, heavy industrialisation , and intense use of the sea and the area surrounding it, various environmental issues affect the sea's ecosystems. Adverse environmental issues – commonly including overfishing , industrial and agricultural runoff , dredging , and dumping, among others – have led to several efforts to prevent degradation and to safeguard long-term economic benefits. The North Sea
14740-402: The order Isoetales (which contains living quillworts ), rose to prominence due to the environmental instability following the Permian-Triassic extinction, with one particularly notable example being the genus Pleuromeia , which grew in columnar like fashion, sometimes reaching a height of 2 metres (6.6 ft). The relevance of lycophytes declined from the Middle Triassic onwards, following
14874-504: The period progressed. Southern Pangea, also known as Gondwana , was made up by closely-appressed cratons corresponding to modern South America , Africa , Madagascar , India , Antarctica , and Australia . North Pangea, also known as Laurussia or Laurasia , corresponds to modern-day North America and the fragmented predecessors of Eurasia . The western edge of Pangea lay at the margin of an enormous ocean, Panthalassa ( lit. ' entire sea ' ), which roughly corresponds to
15008-500: The prevailing flood levels. It was only around the beginning of the High Middle Ages , in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground. The modern form of the dikes supplemented by overflow and lateral diversion channels, began to appear in the 17th and 18th centuries, built in
15142-487: The return of more stable environmental conditions. While having first appeared during the Permian, the extinct seed plant group Bennettitales first became a prominent element in global floras during the Late Triassic, a position they would hold for much of the Mesozoic. In the Southern Hemisphere landmasses of Gondwana, the tree Dicroidium , an extinct " seed fern " belong to the order Corystospermales
15276-469: The sea creating deep fjords and archipelagos . South of Stavanger, the coast softens, the islands become fewer. The eastern Scottish coast is similar, though less severe than Norway. From north east of England , the cliffs become lower and are composed of less resistant moraine , which erodes more easily, so that the coasts have more rounded contours. In the Netherlands, Belgium and in East Anglia
15410-452: The sea, at a depth of only a few metres. The shallow-water coasts of the southern and eastern coast up to Denmark were formed by ice age activity, but their particular shape is determined for the most part by the sea and sediment deposits. The Wadden Sea stretches between Esbjerg , Denmark in the north and Den Helder , Netherlands in the west. This landscape is heavily influenced by the tides and important sections of it have been declared
15544-413: The shores of the sea clogging harbours and inlets and has become a nuisance. Due to the heavy human populations and high level of industrialization along its shores, the wildlife of the North Sea has suffered from pollution, overhunting, and overfishing. Flamingos and pelicans were once found along the southern shores of the North Sea, but became extinct over the second millennium. Walruses frequented
15678-471: The smaller opening at the English Channel. These tidal currents leave along the Norwegian coast. Surface and deep water currents may move in different directions. Low salinity surface coastal waters move offshore, and deeper, denser high salinity waters move inshore. The North Sea located on the continental shelf has different waves from those in deep ocean water. The wave speeds are diminished and
15812-439: The southern North Sea. These soft rock coastal bedrock plains are interspersed with soft rock (shale and sandstone) cliffs. The small, historically strategic island of Heligoland was not formed by recent sediment deposition; it is considerably older and is composed of early Triassic sandstone . North Sea Download coordinates as: The North Sea lies between Great Britain , Denmark , Norway , Germany ,
15946-676: The terminus of the Triassic, there was an extreme warming event referred to as the End-Triassic Thermal Event (ETTE), which was responsible for the Triassic-Jurassic mass extinction. Bubbles of carbon dioxide in basaltic rocks dating back to the end of the Triassic indicate that volcanic activity from the Central Atlantic Magmatic Province helped trigger climate change in the ETTE. During the Early Triassic, lycophytes , particularly those of
16080-595: The terrestrial species had mostly died out during the extinction event. The Triassic survivors were aquatic or semi-aquatic, and were represented by Tupilakosaurus , Thabanchuia , Branchiosauridae and Micropholis , all of which died out in Early Triassic, and the successful Stereospondyli , with survivors into the Cretaceous Period. The largest Triassic stereospondyls, such as Mastodonsaurus , were up to 4 to 6 metres (13 to 20 ft) in length. Some lineages (e.g. trematosaurs ) flourished briefly in
16214-577: The time of the Permo-Triassic boundary; acid rain from the Siberian Traps eruptions or from an impact event that overwhelmed acidic swamps; climate shift to a greenhouse climate that was too hot and dry for peat accumulation; evolution of fungi or herbivores that were more destructive of wetlands; the extinction of all plants adapted to peat swamps, with a hiatus of several million years before new plant species evolved that were adapted to peat swamps; or soil anoxia as oxygen levels plummeted. Before
16348-888: The uplands of the Fennoscandian Shield and the British Isles. This precursor of the current North Sea has grown and shrunk with the rise and fall of the eustatic sea level during geologic time. Sometimes it was connected with other shallow seas, such as the sea above the Paris Basin to the south-west, the Paratethys Sea to the south-east, or the Tethys Ocean to the south. During the Late Cretaceous, about 85 million years ago , all of modern mainland Europe except for Scandinavia
16482-568: The war on the side of Japan. During the First World War , Great Britain's Grand Fleet and Germany's Kaiserliche Marine faced each other in the North Sea, which became the main theatre of the war for surface action. Britain's larger fleet and North Sea Mine Barrage were able to establish an effective blockade for most of the war, which restricted the Central Powers ' access to many crucial resources. Major battles included
16616-561: The war, hundreds of thousands of tons of chemical weapons were disposed of by being dumped in the North Sea. Triassic The Triassic ( / t r aɪ ˈ æ s ɪ k / try- ASS -ik ; sometimes symbolized 🝈 ) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya ), to the beginning of the Jurassic Period 201.4 Mya. The Triassic
16750-406: The wave amplitudes are increased. In the North Sea there are two amphidromic systems and a third incomplete amphidromic system. In the North Sea the average tide difference in wave amplitude is between zero and eight metres (26 ft). The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward. Some of the energy from this wave travels through the English Channel into
16884-615: Was a dominant element in forest habitats across the region during the Middle-Late Triassic. During the Late Triassic, the Ginkgoales (which today are represented by only a single species, Ginkgo biloba ) underwent considerable diversification. Conifers were abundant during the Triassic, and included the Voltziales (which contains various lineages, probably including those ancestral to modern conifers), as well as
17018-673: Was a relatively cool period known as the Early Norian Cool Interval (ENCI), after which occurred the Mid-Norian Warm Interval (MNWI) from 217 to 209 Ma. The MNWI was briefly interrupted around 214 Ma by a cooling possibly related to the Manicouagan impact . Around 212 Ma, a 10 Myr eccentricity maximum caused a paludification of Pangaea and a reduction in the size of arid climatic zones. The Rhaetian Cool Interval (RCI) lasted from 209 to 201 Ma. At
17152-595: Was a scattering of islands. By the Early Oligocene , 34 to 28 million years ago , the emergence of Western and Central Europe had almost completely separated the North Sea from the Tethys Ocean, which gradually shrank to become the Mediterranean as Southern Europe and South West Asia became dry land. The North Sea was cut off from the English Channel by a narrow land bridge until that
17286-505: Was accompanied by huge volcanic eruptions that occurred as the supercontinent Pangaea began to break apart about 202 to 191 million years ago (40Ar/39Ar dates), forming the Central Atlantic Magmatic Province (CAMP), one of the largest known inland volcanic events since the planet had first cooled and stabilized. Other possible but less likely causes for the extinction events include global cooling or even
17420-566: Was breached by at least two catastrophic floods between 450,000 and 180,000 years ago. Since the start of the Quaternary period about 2.6 million years ago , the eustatic sea level has fallen during each glacial period and then risen again. Every time the ice sheet reached its greatest extent, the North Sea became almost completely dry, the dry landmass being known as Doggerland , whose northern regions were themselves known to have been glaciated. The present-day coastline formed after
17554-632: Was cited by Pliny . He also noted that the Cimbri called it Morimarusa – "Dead Sea". The name "North Sea" probably came into English, however, via the Dutch Noordzee , who named it thus either in contrast with the Zuiderzee ("South Sea"), located south of Frisia , or because the sea is generally to the north of the Netherlands. Before the adoption of "North Sea", the names used in English were "German Sea" or "German Ocean", referred to as
17688-484: Was encroached upon by a pair of extensive oceanic basins: The Neo-Tethys (or simply Tethys) and Paleo-Tethys Oceans . These extended from China to Iberia, hosting abundant marine life along their shallow tropical peripheries. They were divided from each other by a long string of microcontinents known as the Cimmerian terranes . Cimmerian crust had detached from Gondwana in the early Permian and drifted northwards during
17822-451: Was named in 1834 by Friedrich August von Alberti , after a succession of three distinct rock layers (Greek triás meaning 'triad') that are widespread in southern Germany : the lower Buntsandstein (colourful sandstone ) , the middle Muschelkalk (shell-bearing limestone ) and the upper Keuper (coloured clay ). On the geologic time scale , the Triassic is usually divided into Early , Middle , and Late Triassic Epochs , and
17956-528: Was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles , especially archosaurs , were the chief terrestrial vertebrates during this time. A specialized group of archosaurs, called dinosaurs , first appeared in
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