Misplaced Pages

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98-512: The relatively thin crust and short lifespan of the Aegir Ridge is anomalous given its proximity to the Iceland hotspot . Mantle hotspots deliver warm, actively-upwelling material to mid-ocean ridges, increasing mantle melting and crustal production. Likely, the stresses associated with plate tectonics and the mechanical structure of the lithosphere created a situation in which spreading at

196-569: A longhouse in Stöðvarfjörður that may date to as early as 800. Swedish Viking explorer Garðar Svavarsson was the first to circumnavigate Iceland in 870 and establish that it was an island. He stayed during the winter and built a house in Húsavík . Garðar departed the following summer, but one of his men, Náttfari , decided to stay behind with two slaves. Náttfari settled in what is now known as Náttfaravík, and he and his slaves became

294-469: A shield volcano with a magma chamber underneath). Several classifications of the systems exist, for example there is one of 30 systems, and one of 34 systems, with the later currently being used in Iceland itself. The climate of Iceland's coast is subarctic . The warm North Atlantic Current ensures generally higher annual temperatures than in most places of similar latitude in the world. Regions in

392-537: A summit in Reykjavík in 1986 between United States President Ronald Reagan and Soviet Premier Mikhail Gorbachev , during which they took significant steps towards nuclear disarmament . A few years later, Iceland became the first country to recognise the independence of Estonia , Latvia , and Lithuania as they broke away from the USSR. Throughout the 1990s, the country expanded its international role and developed

490-444: A 32 percent increase in Iceland's gross national income between 2002 and 2007. In 2003–2007, following the privatisation of the banking sector under the government of Davíð Oddsson , Iceland moved towards having an economy based on international investment banking and financial services. It was quickly becoming one of the most prosperous countries in the world, but was hit hard by a major financial crisis . The crisis resulted in

588-664: A convicted child sex offender. Snap elections in October 2017 brought to power a new coalition consisting of the Independence Party, the Progressive Party, and the Left-Green Movement , headed by Katrín Jakobsdóttir . After the 2021 parliamentary election , the new government was, just like the previous government, a tri-party coalition of the Independence Party, the Progressive Party, and

686-665: A defence agreement was signed with the United States. American troops returned to Iceland as the Iceland Defence Force and remained throughout the Cold War . The US withdrew the last of its forces on 30 September 2006. Iceland prospered during the Second World War. The immediate post-war period was followed by substantial economic growth , driven by the industrialisation of the fishing industry and

784-465: A famine that killed nearly a quarter of the island's population. In addition, the eruption caused dust clouds and haze to appear over most of Europe and parts of Asia and Africa for several months afterwards, and affected climates in other areas. Iceland has many geysers , including Geysir , from which the English word is derived, and the famous Strokkur , which erupts every 8–10 minutes. After

882-603: A foreign policy orientated towards humanitarian and peacekeeping causes. To that end, Iceland provided aid and expertise to various NATO-led interventions in Bosnia , Kosovo , and Iraq . Iceland joined the European Economic Area in 1994, after which the economy was greatly diversified and liberalised. International economic relations increased further after 2001 when Iceland's newly deregulated banks began to raise great amounts of external debt , contributing to

980-725: A fully sovereign and independent state in a personal union with Denmark. The Government of Iceland established an embassy in Copenhagen and requested that Denmark carry out on its behalf certain defence and foreign affairs matters, subject to consultation with the Althing. Danish embassies around the world displayed two coats of arms and two flags: those of the Kingdom of Denmark and those of the Kingdom of Iceland . Iceland's legal position became comparable to those of countries belonging to

1078-516: A hot conduit 100 km (62 mi) across that extends to the lower mantle. Foulger et al. believe the Icelandic plume reaches only to the mantle transition layer and can therefore not come from the same source as Hawaii. Bijwaard and Spakman, however, believe the Icelandic plume does reach to the mantle, and therefore comes from the same source as Hawaii. While the Hawaiian island chain and

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1176-730: A latitude just south of the Arctic Circle . Its latitude and marine influence keep summers chilly, and most of its islands have a polar climate . According to the ancient manuscript Landnámabók , the settlement of Iceland began in 874 AD, when the Norwegian chieftain Ingólfr Arnarson became the island's first permanent settler. In the following centuries, Norwegians , and to a lesser extent other Scandinavians , immigrated to Iceland, bringing with them thralls (i.e., slaves or serfs) of Gaelic origin. The island

1274-470: A low- silica lava associated with effusive volcanism as has occurred also in Hawaii . Iceland, however, has a variety of volcanic types (composite and fissure), many producing more evolved lavas such as rhyolite and andesite . Iceland has hundreds of volcanoes with about 30 active volcanic systems. Surtsey , one of the youngest islands in the world, is part of Iceland. Named after Surtr , it rose above

1372-418: A mantle plume at all, but that the volcanism there results from processes related to plate tectonics and is restricted to the upper mantle . According to one of those models, a large chunk of the subducted plate of a former ocean has survived in the uppermost mantle for several hundred million years, and its oceanic crust now causes excessive melt generation and the observed volcanism. This model, however,

1470-542: A part of the submarine volcanic system of mid-oceanic ridges . The initial plume head may have been several thousand kilometers in diameter, and it erupted volcanic rocks on both sides of the present ocean basin to produce the North Atlantic Igneous Province . Upon further opening of the ocean and plate drift, the plume and the mid-Atlantic Ridge are postulated to have approached one another, and finally met. The excess magmatism that accompanied

1568-406: A phase of inactivity, Geysir started erupting again after a series of earthquakes in 2000 . Geysir has since grown quieter and does not erupt often. With the widespread availability of geothermal power and the harnessing of many rivers and waterfalls for hydroelectricity , most residents have access to inexpensive hot water, heating, and electricity. The island is composed primarily of basalt ,

1666-641: A popular holiday destination. In 2016, Prime Minister Sigmundur Davíð Gunnlaugsson resigned after being implicated in the Panama Papers scandal. Early elections in 2016 resulted in a right-wing coalition government of the Independence Party , the Reform Party and Bright Future . This government fell when Bright Future quit the coalition due to a scandal involving then-Prime Minister Bjarni Benediktsson 's father's letter of support for

1764-504: A region of higher temperature than the surrounding mantle , the hotspot is believed to have a higher concentration of water . The presence of water in magma reduces the melting temperature, which may also play a role in enhancing Icelandic volcanism. There is an ongoing discussion about whether the hotspot is caused by a deep mantle plume or originates at a much shallower depth. Recently, seismic tomography studies have found seismic wave speed anomalies under Iceland, consistent with

1862-429: A republic in 1944, ending the remaining formal ties to Denmark. Although the Althing was suspended from 1799 to 1845, Iceland nevertheless has a claim to sustaining one of the world's longest-running parliaments. Until the 20th century, Iceland relied largely on subsistence fishing and agriculture. Industrialization of the fisheries and Marshall Plan aid after World War II brought prosperity, and Iceland became one of

1960-489: A society where subsistence depended almost entirely on agriculture. The Black Death swept Iceland twice, first in 1402–1404 and again in 1494–1495. The former outbreak killed 50% to 60% of the population, and the latter 30% to 50%. Around the middle of the 16th century, as part of the Protestant Reformation , King Christian III of Denmark began to impose Lutheranism on all his subjects. Jón Arason ,

2058-407: A third of the basaltic lavas erupted in recorded history have been produced by Icelandic eruptions. Notable eruptions have included that of Eldgjá , a fissure of Katla , in 934 (the world's largest basaltic eruption ever witnessed), Laki in 1783 (the world's second largest), and several eruptions beneath ice caps , which have generated devastating glacial bursts , most recently in 2010 after

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2156-611: Is a Nordic island country between the North Atlantic and Arctic Oceans , on the Mid-Atlantic Ridge between North America and Europe . It is culturally and politically linked with Europe and is the region's westernmost and most sparsely populated country . Its capital and largest city is Reykjavík , which is home to about 36% of the country's roughly 380,000 residents (excluding nearby towns/suburbs which are separate municipalities). The official language of

2254-515: Is a hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland . It contributes to understanding the geological deformation of Iceland . Iceland is one of the most active volcanic regions in the world, with eruptions occurring on average roughly every three years (in the 20th and 21st century until 2010 there were 45 volcanic eruptions on and around Iceland). About

2352-566: Is a sitka spruce planted in 1949 in Kirkjubæjarklaustur ; it was measured at 25.2 m (83 ft) in 2013. Algae such as Chondrus crispus , Phyllphora truncata and Phyllophora crispa and others have been recorded from Iceland. The only native land mammal when humans arrived was the Arctic fox , which came to the island at the end of the ice age, walking over the frozen sea. On rare occasions, bats have been carried to

2450-576: Is a marker that indicates the origin of the mantle involved in eruptions. Helium-3 is captured during planetary accretion, thus is associated with relatively deeper or lower mantle. Helium-4 is created from the decay of uranium and thorium parent isotopes. A low ratio of He to He is strongly correlated with mid ocean ridge eruptions due to its shallow source of mantle, while high ratios of He to He are correlated with ocean island basalts due to its deeper source of mantle. Both high and low ratios of He to He are found on Iceland. High ratios are associated with

2548-460: Is a postulated upwelling of anomalously hot rock in the Earth's mantle beneath Iceland . Its origin is thought to lie deep in the mantle, perhaps at the boundary between the core and the mantle at about 2,880 km (1,790 mi) depth. Opinions differ as to whether seismic studies have imaged such a structure. In this framework, the volcanism of Iceland is attributed to this plume, according to

2646-501: Is also where most settlements are situated. The island's interior, the Highlands of Iceland , is a cold and uninhabitable combination of sand, mountains, and lava fields . The major towns are the capital city of Reykjavík , along with its outlying towns of Kópavogur , Hafnarfjörður , and Garðabær , nearby Reykjanesbær where the international airport is located, and the town of Akureyri in northern Iceland. The island of Grímsey on

2744-460: Is closer to continental Europe than to mainland North America, although it is closest to Greenland (290 kilometres; 155 nautical miles), an island of North America. Iceland is generally included in Europe for geographical, historical, political, cultural, linguistic and practical reasons. Geologically, the island includes parts of both continental plates. The closest bodies of land in Europe are

2842-459: Is more than 20 million years old and was formed at an old oceanic spreading center in the Westfjords (Vestfirðir) region. The westward movement of the plates and the ridge above the plume and the strong thermal anomaly of the latter caused this old spreading center to cease 15 million years ago and lead to the formation of a new one in the area of today's peninsulas Skagi and Snæfellsnes ; in

2940-399: Is not backed by dynamical calculations, nor is it exclusively required by the data, and it also leaves unanswered questions concerning the dynamical and chemical stability of such a body over that long period or the thermal effect of such massive melting. Another model proposes that the upwelling in the Iceland region is driven by lateral temperature gradients between the suboceanic mantle and

3038-412: Is regarded to lie at about 150 parts per million. The presence of such a large amount of water in the source of the lavas would tend to lower its melting point and make it more productive for a given temperature. It would also produce the higher melt temperatures found, than typical of mid-ocean ridge basalts. The north Atlantic is characterized by strong, large-scale anomalies of the gravity field and

Aegir Ridge - Misplaced Pages Continue

3136-407: Is the surface expression of the Iceland Plateau , a large igneous province forming as a result of volcanism from the Iceland hotspot and along the Mid-Atlantic Ridge , the latter of which runs right through it. This means that the island is highly geologically active with many volcanoes including Hekla , Eldgjá , Herðubreið , and Eldfell . The volcanic eruption of Laki in 1783–1784 caused

3234-533: Is whether the plume is thought to have ascended from the deep mantle only at that time or whether it is much older and also responsible for the old volcanism in northern Greenland, on Ellesmere Island , and at Alpha Ridge in the Arctic. As the northern Atlantic opened to the east of Greenland during the Eocene, North America and Eurasia drifted apart; the Mid-Atlantic Ridge formed as an oceanic spreading center and

3332-463: The Boreal Kingdom . Plantlife consists mainly of grassland, which is regularly grazed by livestock. The most common tree native to Iceland is the northern birch ( Betula pubescens ), which formerly formed forests over much of Iceland, along with aspens ( Populus tremula ), rowans ( Sorbus aucuparia ), common junipers ( Juniperus communis ), and other smaller trees, mainly willows. When

3430-751: The Emperor Seamounts show a clear time-progressive volcanic track caused by the movement of the Pacific Plate over the Hawaiian hotspot, no such track can be seen at Iceland. It is proposed that the line from Grímsvötn volcano to Surtsey shows the movement of the Eurasian Plate , and the line from Grímsvötn volcano to the Reykjanes volcanic belt shows the movement of the North American Plate. The Iceland plume

3528-602: The Faroe Islands (420 km; 225 nmi); Jan Mayen Island (570 km; 310 nmi); Shetland and the Outer Hebrides , both about 740 km (400 nmi); and the Scottish mainland and Orkney , both about 750 km (405 nmi). The nearest part of Continental Europe is mainland Norway, about 970 km (525 nmi) away, while mainland North America is 2,070 km (1,120 nmi) away, at

3626-471: The Kolbeinsey Ridge. Depending on which elements are considered and how large the area covered is, one can identify up to six different mantle components, which are not all present in any single location. Furthermore, some studies show that the amount of water dissolved in mantle minerals is two to six times higher in the Iceland region than in undisturbed parts of the mid-oceanic ridges, where it

3724-589: The Little Ice Age , and overgrazing by sheep imported by settlers caused a loss of critical topsoil due to erosion . Today, many farms have been abandoned. Three-quarters of Iceland's 100,000 square kilometres (39,000 sq mi) is affected by soil erosion; 18,000 km (6,900 sq mi) is affected to a degree serious enough to make the land useless. Only a few small birch stands now exist in isolated reserves. The Icelandic Forest Service and other forestry groups promote large-scale reforestation in

3822-529: The Mid-Atlantic Ridge , a ridge along which the oceanic crust spreads and forms new crust. This part of the mid-ocean ridge is located above a mantle plume, causing Iceland to be subaerial (above the surface of the sea). The ridge marks the boundary between the Eurasian and North American Plates , and Iceland was created by rifting and accretion through volcanism along the ridge. Many fjords punctuate Iceland's 4,970-km-long (3,088-mi) coastline, which

3920-714: The Scandinavian Mountains by producing changes in the density of the lithosphere and asthenosphere during the opening of the North Atlantic. To the south the Paleogene uplift of the English chalklands that resulted in the formation of the Sub-Paleogene surface has also been attributed to the Iceland plume. An extinct ridge exists in western Iceland, leading to the theory that the plume has shifted east with time. The oldest crust of Iceland

4018-704: The Treaty of Kiel formally ceded Iceland to Denmark in 1814. Influenced by ideals of nationalism after the French Revolution , Iceland's struggle for independence took form and culminated in the Danish–Icelandic Act of Union in 1918, with the establishment of the Kingdom of Iceland , sharing through a personal union the incumbent monarch of Denmark . During the occupation of Denmark in World War II, Iceland voted overwhelmingly to become

Aegir Ridge - Misplaced Pages Continue

4116-463: The Vestmannaeyjar archipelago. Lakes and glaciers cover 14.3% of its surface; only 23% is vegetated. The largest lakes are Þórisvatn reservoir: 83–88 km (32–34 sq mi) and Þingvallavatn : 82 km (32 sq mi); other important lakes include Lagarfljót and Mývatn . Jökulsárlón is the deepest lake, at 248 m (814 ft). Geologically, Iceland is part of

4214-469: The geoid . The geoid rises up to 70 m (230 ft) above the geodetic reference ellipsoid in an approximately circular area with a diameter of several hundred kilometers. In the context of the plume hypothesis, this has been explained by the dynamic effect of the upwelling plume which bulges up the surface of the Earth. Furthermore, the plume and the thickened crust cause a positive gravity anomaly of about 60 mGal (=0.0006 m/s²) (free-air). Since

4312-468: The plume model, the source of Icelandic volcanism lies deep beneath the center of the island. The earliest volcanic rocks attributed to the plume are found on both sides of the Atlantic. Their ages have been determined to lie between 64 and 58 million years. This coincides with the opening of the north Atlantic in the late Paleocene and early Eocene , which has led to suggestions that the arrival of

4410-619: The 1850s under the leadership of Jón Sigurðsson , based on the burgeoning Icelandic nationalism inspired by the Fjölnismenn and other Danish-educated Icelandic intellectuals. In 1874, Denmark granted Iceland a constitution and limited home rule. This was expanded in 1904, and Hannes Hafstein served as the first Minister for Iceland in the Danish cabinet. The Danish–Icelandic Act of Union , an agreement with Denmark signed on 1 December 1918 and valid for 25 years, recognised Iceland as

4508-621: The Arctic Circle contains the northernmost habitation of Iceland, whereas Kolbeinsey contains the northernmost point of Iceland. Iceland has three national parks : Vatnajökull National Park , Snæfellsjökull National Park , and Þingvellir National Park . The country is considered a "strong performer" in environmental protection, having been ranked 13th in Yale University 's Environmental Performance Index of 2012. A geologically young land at 16 to 18 million years old, Iceland

4606-587: The Commonwealth of Nations, such as Canada, whose sovereign is King Charles III . During World War II, Iceland joined Denmark in asserting neutrality. After the German occupation of Denmark on 9 April 1940, the Althing replaced the King with a regent and declared that the Icelandic government would take control of its own defence and foreign affairs. A month later, British armed forces conducted Operation Fork ,

4704-500: The Kolbeinsey Ridge was energetically favorable to spreading at the Aegir Ridge. As the Kolbeinsey Ridge began rifting, hotspot material would then draw out of the Aegir Ridge and flow preferentially towards the Kolbeinsey Ridge, leading to the ultimate extinction of the spreading center. This tectonics article is a stub . You can help Misplaced Pages by expanding it . Iceland hotspot The Iceland hotspot

4802-635: The Left-Green Movement, headed by Prime Minister Katrín Jakobsdóttir. In April 2024, Bjarni Benediktsson of the Independence party succeeded Katrín Jakobsdóttir as prime minister. Iceland is at the juncture of the North Atlantic and Arctic Oceans. The main island is entirely south of the Arctic Circle , which passes through the small Icelandic island of Grímsey off the main island's northern coast. The country lies between latitudes 63 and 68°N , and longitudes 25 and 13°W . Iceland

4900-700: The US Marshall Plan programme, through which Icelanders received the most aid per capita of any European country (at US$ 209, with the war-ravaged Netherlands a distant second at US$ 109). Vigdís Finnbogadóttir assumed Iceland's presidency on 1 August 1980, making her the first elected female head of state in the world. The 1970s were marked by the Cod Wars —several disputes with the United Kingdom over Iceland's extension of its fishing limits to 200 nmi (370 km) offshore. Iceland hosted

4998-472: The area under consideration is "illuminated" from all sides with seismic waves from earthquakes from as many different directions as possible; these waves are recorded with a network of seismometers . The size of the network is crucial for the extent of the region which can be imaged reliably. For the investigation of the Iceland Plume, both global and regional tomography have been used; in the former,

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5096-432: The basalt in subducted slabs and is more easily fusible than peridotite. The origin of the latter is assumed to be metamorphosed, very old oceanic crust which sank into the mantle several hundreds of millions of years ago during the subduction of an ocean, then upwelled from deep within the mantle. Studies using the major and trace-element compositions of Icelandic volcanics showed that the source of present-day volcanism

5194-463: The country is Icelandic . Iceland is on a rift between tectonic plates , and its geologic activity includes geysers and frequent volcanic eruptions . The interior consists of a volcanic plateau with sand and lava fields , mountains and glaciers , and many glacial rivers flow to the sea through the lowlands . Iceland is warmed by the Gulf Stream and has a temperate climate , despite

5292-575: The country's climate continued to grow colder, resulting in mass emigration to the New World , particularly to the region of Gimli , Manitoba in Canada, which was sometimes referred to as New Iceland . About 15,000 people emigrated, out of a total population of 70,000. A national consciousness arose in the first half of the 19th century, inspired by romantic and nationalist ideas from mainland Europe. An Icelandic independence movement took shape in

5390-416: The country's total exports. Birds, especially seabirds, are an important part of Iceland's animal life. Atlantic puffins , skuas , and black-legged kittiwakes nest on its sea cliffs. Commercial whaling is practised intermittently along with scientific whale hunts. Whale watching has become an important part of Iceland's economy since 1997. Around 1,300 species of insects are known in Iceland. This

5488-417: The country. Due to the reforestation efforts, the forest cover of Iceland increased six-fold since the 1990s. This helps to offset carbon emissions, prevent sand storms and increase the productivity of farms. The planting of new forests has increased the number of trees, but the result does not compare to the original forests. Some of the planted forests include introduced species . The tallest tree in Iceland

5586-410: The enhanced igneous crustal thickness found along the southern Aegir and Kolbeinsey ridges may be results of interaction between the plume and the Mid-Atlantic Ridge . The plume stem is believed to be quite narrow, perhaps 100 km (62 mi) across and extending down to at least 400–650 km (250–400 mi) beneath the Earth's surface, and possibly down to the core-mantle boundary , while

5684-408: The eruption of Eyjafjallajökull . Iceland's location astride the Mid-Atlantic Ridge , where the Eurasian and North American Plates are moving apart, is partly responsible for this intense volcanic activity, but an additional cause is necessary to explain why Iceland is a substantial island while the rest of the ridge mostly consists of seamounts , with peaks below sea level . As well as being

5782-527: The eruption, known as the Mist Hardships ( Icelandic : Móðuharðindin ), over half of all livestock in the country died. Around a quarter of the population starved to death in the ensuing famine . In 1814, following the Napoleonic Wars , Denmark-Norway was broken up into two separate kingdoms via the Treaty of Kiel , but Iceland remained a Danish dependency. Throughout the 19th century,

5880-588: The events known locally as the Turkish Abductions , in which hundreds of residents were taken into slavery in North Africa and dozens killed; this was the only invasion in Icelandic history to have casualties. The 1707–08 Iceland smallpox epidemic is estimated to have killed a quarter to a third of the population. In 1783 the Laki volcano erupted, with devastating effects. In the years following

5978-469: The first permanent residents of Iceland to be documented. The Norwegian-Norse chieftain Ingólfr Arnarson built his homestead in present-day Reykjavík in 874. Ingólfr was followed by many other emigrant settlers, largely Scandinavians and their thralls , many of whom were Irish or Scottish . By 930, most arable land on the island had been claimed; the Althing , a legislative and judicial assembly

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6076-401: The geochemical signature of the lavas present on Iceland and in the north Atlantic. The resulting picture is consistent in several important respects. For instance, it is not contested that the source of the volcanism in the mantle is chemically and petrologically heterogeneous: it contains not only peridotite , the principal mantle rock type, but also eclogite, a rock type that originates from

6174-471: The greatest migration from Iceland since 1887, with a net emigration of 5,000 people in 2009. Iceland's economy stabilised under the government of Jóhanna Sigurðardóttir and grew by 1.6% in 2012. The centre-right Independence Party was returned to power in coalition with the Progressive Party in the 2013 election. In the following years, Iceland saw a surge in tourism as the country became

6272-482: The invasion and occupation of the country, violating Icelandic neutrality . In 1941, the Government of Iceland, friendly to Britain, invited the then-neutral United States to take over its defence so that Britain could use its troops elsewhere. On 31 December 1943, the Danish–Icelandic Act of Union expired after 25 years. Beginning on 20 May 1944, Icelanders voted in a four-day plebiscite on whether to terminate

6370-413: The investigation of postulated plumes, gravimetric , geoid and in particular seismological methods along with geochemical analyses of erupted lavas have proven especially useful. Numerical models of the geodynamical processes attempt to merge these observations into a consistent general picture. An important method for imaging large-scale structures in Earth's interior is seismic tomography , by which

6468-527: The island was first settled, it was extensively forested, with around 30% of the land covered in trees. In the late 12th century, Ari the Wise described it in the Íslendingabók as "forested from mountain to sea shore". Permanent human settlement greatly disturbed the isolated ecosystem of thin, volcanic soils and limited species diversity . The forests were heavily exploited over the centuries for firewood and timber. Deforestation , climatic deterioration during

6566-440: The island was then called Garðarshólmur, which means "Garðar's Isle". Then came a Viking named Flóki Vilgerðarson ; his daughter drowned en route, then his livestock starved to death. The sagas say that the rather despondent Flóki climbed a mountain and saw a fjord ( Arnarfjörður ) full of icebergs, which led him to give the island its new and present name. The notion that Iceland's Viking settlers chose that name to discourage

6664-568: The island with the winds, but they are not able to breed there. No native or free-living reptiles or amphibians are on the island. The animals of Iceland include the Icelandic sheep , cattle , chickens , goats , the sturdy Icelandic horse , and the Icelandic Sheepdog , all descendants of animals imported by Europeans. Wild mammals include the Arctic fox, mink , mice, rats, rabbits, and reindeer . Polar bears occasionally visit

6762-415: The island, travelling from Greenland on icebergs, but no Icelandic populations exist. In June 2008, two polar bears arrived in the same month. Marine mammals include the grey seal ( Halichoerus grypus ) and harbour seal ( Phoca vitulina ). Many species of fish live in the ocean waters surrounding Iceland, and the fishing industry is a major part of Iceland's economy, accounting for roughly half of

6860-437: The last Catholic bishop of Hólar , was beheaded in 1550 along with two of his sons. The country subsequently became officially Lutheran, and Lutheranism has since remained the dominant religion. In the 17th and 18th centuries, Denmark imposed harsh trade restrictions on Iceland. Natural disasters, including volcanic eruptions and disease, contributed to a decreasing population. In the summer of 1627, Barbary Pirates committed

6958-506: The latter there is still some activity in the form of the Snæfellsjökull volcano. The spreading center, and hence the main activity, shifted eastward again 9 to 7 million years ago and formed the current volcanic zones in the south–west ( Reykjanes , Hofsjökull ) and north–east ( Tjörnes ). Presently, a slow decrease of the activity in the north–east takes place, while the volcanic zone in the south–east ( Katla , Vatnajökull ), which

7056-550: The magma was originally at a depth of 24 km (15 mi). The resulting velocity of the magma ascension was calculated to be 0.02-0.1 m/s so that magma takes a mean of 10 days to reach the surface of Iceland from the Moho discontinuity which is faster than previously thought. 64°24′00″N 17°18′00″W  /  64.4000°N 17.3000°W  / 64.4000; -17.3000 Iceland Iceland ( Icelandic : Ísland , pronounced [ˈistlant] )

7154-455: The mantle transition zone at roughly 600 km (370 mi) depth. The velocities of seismic waves are reduced by up to 3% ( P waves ) and more than 4% ( S waves ), respectively. These values are consistent with a small percentage of partial melt, a high magnesium content of the mantle, or elevated temperature. It is not possible to unambiguously separate out which effect causes the observed velocity reduction. Numerous studies have addressed

7252-461: The mechanics of magma movement under Iceland. A study on the Borgarhraun basalt flow helped to constrain the velocity of magma transport from great depths to the surface. Geothermal barometry and statistical analysis of aluminium within olivine crystals allowed the researchers to determine the depth that these crystals were formed in and how long it took them to reach the surface. In this case,

7350-417: The mid-1990s several attempts have been made to explain the observations with numerical geodynamical models of mantle convection . The purpose of these calculations was, among other things, to resolve the paradox that a broad plume with a relatively low temperature anomaly is in better agreement with the observed crustal thickness, topography, and gravity than a thin, hot plume, which has been invoked to explain

7448-494: The neighbouring Greenland craton and therefore also restricted to the upper 200–300 km (120–190 mi) of the mantle. However, this convection mechanism is probably not strong enough under the conditions prevailing in the north Atlantic, with respect to the spreading rate, and it does not offer a simple explanation for the observed geoid anomaly. Information about the structure of Earth's deep interior can be acquired only indirectly by geophysical and geochemical methods. For

7546-481: The northeastern hinterland. The temperature records for Reykjavík are 26.2 °C (79.2 °F) on 30 July 2008, and −24.5 °C (−12.1 °F) on 21 January 1918. The entire country is in a single ecoregion , the Iceland boreal birch forests and alpine tundra . Some areas are covered by glaciers . Phytogeographically , Iceland belongs to the Arctic province of the Circumboreal Region within

7644-410: The northern tip of Labrador . Iceland is the world's 18th-largest island , and Europe's second-largest island after Great Britain and before Ireland. The main island covers 101,826 km (39,315 sq mi), but the entire country is 103,000 km (40,000 sq mi) in size, of which 62.7% is tundra . Iceland contains about 30 minor islands, including the lightly populated Grímsey and

7742-401: The ocean in a series of volcanic eruptions between 8 November 1963 and 5 June 1968. Only scientists researching the growth of new life are allowed to visit the island. The country has around 30 active volcanic systems. Within each are volcano-tectonic fissure systems and many, but not all of them, also have at least one central volcano (mostly in the form of a stratovolcano , sometimes of

7840-517: The personal union with Denmark, abolish the monarchy, and establish a republic. The vote was 97% to end the union, and 95% in favour of the new republican constitution. Iceland formally became a republic on 17 June 1944, with Sveinn Björnsson as its first president. In 1946, the US Defence Force Allied left Iceland. The nation formally became a member of NATO on 30 March 1949, amid domestic controversy and riots . On 5 May 1951,

7938-407: The plume head may be greater than 1,000 km (620 mi) in diameter. It is suggested that the lack of a time-progressive track of seamounts is due to the location of the plume beneath the thick Greenland craton (Laurentia) for ~ 15 Myr after continental breakup, and the later entrenchment of the plume material into the northern Mid-Atlantic Ridge following its formation. According to

8036-412: The plume was linked to, and has perhaps contributed to, the breakup of Laurasia . In the framework of the plume hypothesis, the volcanism was caused by the flow of hot plume material initially beneath thick continental lithosphere and then beneath the lithosphere of the growing ocean basin as rifting proceeded. The exact position of the plume at that time is a matter of disagreement between scientists, as

8134-438: The seismological and geochemical observations. The most recent models prefer a plume that is 180–200 °C (356–392 °F) hotter than the surrounding mantle and has a stem with a radius of about 100 km (62 mi). Such temperatures have not yet been confirmed by petrology , however. Understanding how magma is transported from great depths near the Moho discontinuity to the surface has implications for understanding

8232-578: The settlement of their verdant isle is most likely a myth. According to both Landnámabók and Íslendingabók , monks known as the Papar lived in Iceland before Scandinavian settlers arrived, possibly members of a Hiberno-Scottish mission . An archaeological excavation has revealed the ruins of a cabin in Hafnir on the Reykjanes peninsula . Carbon dating indicates that it was abandoned sometime between 770 and 880. In 2016, archaeologists uncovered

8330-668: The signing of the Old Covenant in 1262, which ended the Commonwealth and brought Iceland under the Norwegian crown. Possession of Iceland passed from the Kingdom of Norway (872–1397) to the Kalmar Union in 1415, when the kingdoms of Norway, Denmark, and Sweden were united. After the break-up of the union in 1523, it remained a Norwegian dependency, as a part of Denmark–Norway . Infertile soil, volcanic eruptions, deforestation, and an unforgiving climate made for harsh life in

8428-480: The smallest population of any NATO member and is the only one with no standing army , possessing only a lightly armed coast guard . The Sagas of Icelanders say that a Norwegian named Naddodd (or Naddador) was the first Norseman to reach Iceland; in the ninth century, he named it Snæland or "Snowland" because it was snowing. Following Naddodd, the Swede Garðar Svavarsson arrived, and so

8526-463: The south coast is warmer, wetter, and windier than the north. The Central Highlands are the coldest part of the country. Low-lying inland areas in the north are the aridest. Snowfall in winter is more common in the north than in the south. The highest air temperature recorded was 30.5 °C (86.9 °F) on 22 June 1939 at Teigarhorn on the southeastern coast. The lowest was −38 °C (−36.4 °F) on 22 January 1918 at Grímsstaðir and Möðrudalur in

8624-489: The theory of W. Jason Morgan . It is believed that a mantle plume underlies Iceland, of which the hotspot is thought to be the surface expression, and that the presence of the plume enhances the volcanism already caused by plate separation. Additionally, flood basalts on the continental margins of Greenland and Norway , the oblique orientation of the Reykjanes Ridge segments to their spreading direction, and

8722-468: The transition from flood volcanism on Greenland, Ireland and Norway to present-day Icelandic activity was the result of ascent of the hot mantle source beneath progressively thinning lithosphere, according to the plume model, or a postulated unusually productive part of the mid-ocean ridge system. Some geologists have suggested that the Iceland plume could have been responsible for the Paleogene uplift of

8820-449: The western portion of the island, while lower ratios are associated with the eastern part of the island. These ratio trends correlate well with geophysical anomalies, and the decrease of this and other geochemical signatures with increasing distance from Iceland. Combined, they indicate that the extent of the compositional anomaly reaches about 1,500 km (930 mi) along the Reykjanes Ridge and at least 300 km (190 mi) along

8918-421: The whole mantle is imaged at relatively low resolution using data from stations all over the world, whereas in the latter, a denser network only on Iceland images the mantle down to 400–450 km (250–280 mi) depth with higher resolution. Regional studies from the 1990s and 2000s show that there is a low seismic-wave-speed anomaly beneath Iceland, but opinion is divided as to whether it continues deeper than

9016-550: The world with similar climates include the Aleutian Islands , the Alaska Peninsula , and Tierra del Fuego , although these regions are closer to the equator. Despite its proximity to the Arctic, the island's coasts remain ice-free through the winter. Ice incursions are rare, with the last having occurred on the north coast in 1969. The climate varies between different parts of the island. Generally speaking,

9114-680: The world's wealthiest and most developed nations. In 1994 it became a part of the European Economic Area , further diversifying its economy into sectors such as finance, biotechnology, and manufacturing . Iceland has a market economy with relatively low taxes , compared to other OECD countries, as well as the highest trade union membership in the world . It maintains a Nordic social welfare system that provides universal health care and tertiary education . Iceland ranks highly in international comparisons of national performance, such as quality of life, education, protection of civil liberties, government transparency, and economic freedom. It has

9212-434: Was about 100 °C (212 °F) greater than that of the source of mid-ocean ridge basalts. The variations in the concentrations of trace elements such as helium , lead , strontium , neodymium , and others show clearly that Iceland is compositionally distinct from the rest of the north Atlantic. An example of this is seen in the ratio of helium-3 ( He) to helium-4 ( He) isotopes . The ratio of helium-3 and helium-4

9310-515: Was adopted by consensus around 999–1000, although Norse paganism persisted among segments of the population for some years afterward. The Icelandic Commonwealth lasted until the 13th century when the political system devised by the original settlers proved unable to cope with the increasing power of Icelandic chieftains. The internal struggles and civil strife of the Age of the Sturlungs led to

9408-493: Was governed as an independent commonwealth under the native parliament, the Althing , one of the world's oldest functioning legislative assemblies. After a period of civil strife , Iceland acceded to Norwegian rule in the 13th century. In 1397, Iceland followed Norway's integration into the Kalmar Union along with the kingdoms of Denmark and Sweden, coming under de facto Danish rule upon its dissolution in 1523. The Danish kingdom introduced Lutheranism by force in 1550, and

9506-407: Was initiated 3 million years ago, develops. The reorganisation of the plate boundaries in Iceland has also been attributed to microplate tectonics, and an independent Hreppar microplate exists. The weak visibility of the postulated plume in tomographic images of the lower mantle and the geochemical evidence for eclogite in the mantle source have led to the theory that Iceland is not underlain by

9604-558: Was initiated to regulate the Icelandic Commonwealth . The lack of arable land also served as an impetus to the settlement of Greenland starting in 986. The period of these early settlements coincided with the Medieval Warm Period , when temperatures were similar to those of the early 20th century. At this time about 25% of Iceland was covered with forest, compared to 1% in the present day. Christianity

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