130-514: Hveragerði ( Icelandic pronunciation: [ˈkʰvɛːraˌcɛrðɪ, ˈxʷɛː-] , "hot-spring yard") is a town and municipality in the south of Iceland , 45 km east of Reykjavík on Iceland's main ringroad, Route 1 . The river Varmá runs through the town. Hveragerði is the third smallest municipality in Iceland by size. The surrounding area is part of the Hengill central volcano , and
260-569: 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
390-414: 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
520-537: 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
650-549: 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 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 ,
780-444: 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
910-439: A consequence, a powerful source generating plate motion is the excess density of the oceanic lithosphere sinking in subduction zones. When the new crust forms at mid-ocean ridges, this oceanic lithosphere is initially less dense than the underlying asthenosphere, but it becomes denser with age as it conductively cools and thickens. The greater density of old lithosphere relative to the underlying asthenosphere allows it to sink into
1040-664: 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
1170-665: 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
1300-465: 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
1430-450: A few tens of millions of years. Armed with the knowledge of a new heat source, scientists realized that Earth would be much older, and that its core was still sufficiently hot to be liquid. By 1915, after having published a first article in 1912, Alfred Wegener was making serious arguments for the idea of continental drift in the first edition of The Origin of Continents and Oceans . In that book (re-issued in four successive editions up to
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#17327721764471560-603: 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
1690-725: 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
1820-579: A layer of basalt (sial) underlies the continental rocks. However, based on abnormalities in plumb line deflection by the Andes in Peru, Pierre Bouguer had deduced that less-dense mountains must have a downward projection into the denser layer underneath. The concept that mountains had "roots" was confirmed by George B. Airy a hundred years later, during study of Himalayan gravitation, and seismic studies detected corresponding density variations. Therefore, by
1950-470: 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
2080-400: A misnomer as there is no force "pushing" horizontally, indeed tensional features are dominant along ridges. It is more accurate to refer to this mechanism as "gravitational sliding", since the topography across the whole plate can vary considerably and spreading ridges are only the most prominent feature. Other mechanisms generating this gravitational secondary force include flexural bulging of
2210-406: 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 ,
2340-641: 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
2470-429: 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
2600-558: A secondary phenomenon of this basically vertically oriented mechanism. It finds its roots in the Undation Model of van Bemmelen . This can act on various scales, from the small scale of one island arc up to the larger scale of an entire ocean basin. Alfred Wegener , being a meteorologist , had proposed tidal forces and centrifugal forces as the main driving mechanisms behind continental drift ; however, these forces were considered far too small to cause continental motion as
2730-489: 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 ,
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#17327721764472860-407: A solid crust and mantle and a liquid core, but there seemed to be no way that portions of the crust could move around. Many distinguished scientists of the time, such as Harold Jeffreys and Charles Schuchert , were outspoken critics of continental drift. Despite much opposition, the view of continental drift gained support and a lively debate started between "drifters" or "mobilists" (proponents of
2990-478: A static Earth without moving continents up until the major breakthroughs of the early sixties. Two- and three-dimensional imaging of Earth's interior ( seismic tomography ) shows a varying lateral density distribution throughout the mantle. Such density variations can be material (from rock chemistry), mineral (from variations in mineral structures), or thermal (through thermal expansion and contraction from heat energy). The manifestation of this varying lateral density
3120-519: Is geothermally active and experiences very frequent (usually minor) earthquakes . The town is known for its greenhouses , which are heated by hot water from volcanic hot springs . The first greenhouse was built in 1923. These springs are the site of occurrence of certain extremophile micro-organisms, that are capable of surviving in extremely hot environments. Close to the church is a hot spring called Sandhólshver ( [ˈsantˌhoulsˌkʰvɛːr̥, -xʷɛːr̥] , "sand hill hot-spring"), formed during
3250-438: Is mantle convection from buoyancy forces. How mantle convection directly and indirectly relates to plate motion is a matter of ongoing study and discussion in geodynamics. Somehow, this energy must be transferred to the lithosphere for tectonic plates to move. There are essentially two main types of mechanisms that are thought to exist related to the dynamics of the mantle that influence plate motion which are primary (through
3380-566: 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
3510-501: 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
3640-527: Is based on their modes of formation. Oceanic crust is formed at sea-floor spreading centers. Continental crust is formed through arc volcanism and accretion of terranes through plate tectonic processes. Oceanic crust is denser than continental crust because it has less silicon and more of the heavier elements than continental crust . As a result of this density difference, oceanic crust generally lies below sea level , while continental crust buoyantly projects above sea level. Average oceanic lithosphere
3770-461: Is called a plate boundary . Plate boundaries are where geological events occur, such as earthquakes and the creation of topographic features such as mountains , volcanoes , mid-ocean ridges , and oceanic trenches . The vast majority of the world's active volcanoes occur along plate boundaries, with the Pacific plate's Ring of Fire being the most active and widely known. Some volcanoes occur in
3900-533: Is called the geosynclinal theory . Generally, this was placed in the context of a contracting planet Earth due to heat loss in the course of a relatively short geological time. It was observed as early as 1596 that the opposite coasts of the Atlantic Ocean—or, more precisely, the edges of the continental shelves —have similar shapes and seem to have once fitted together. Since that time many theories were proposed to explain this apparent complementarity, but
4030-460: 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
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4160-515: 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 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
4290-492: Is in motion, presents a problem. The same holds for the African, Eurasian , and Antarctic plates. Gravitational sliding away from mantle doming: According to older theories, one of the driving mechanisms of the plates is the existence of large scale asthenosphere/mantle domes which cause the gravitational sliding of lithosphere plates away from them (see the paragraph on Mantle Mechanisms). This gravitational sliding represents
4420-408: Is invoked as the major driving force, through slab pull along subduction zones. Gravitational sliding away from a spreading ridge is one of the proposed driving forces, it proposes plate motion is driven by the higher elevation of plates at ocean ridges. As oceanic lithosphere is formed at spreading ridges from hot mantle material, it gradually cools and thickens with age (and thus adds distance from
4550-511: Is low compared with other countries (over one million species have been described worldwide). Iceland is essentially free of mosquitoes . Plate tectonics Plate tectonics (from Latin tectonicus , from Ancient Greek τεκτονικός ( tektonikós ) 'pertaining to building') is the scientific theory that Earth 's lithosphere comprises a number of large tectonic plates , which have been slowly moving since 3–4 billion years ago. The model builds on
4680-415: Is still advocated to explain the break-up of supercontinents during specific geological epochs. It has followers amongst the scientists involved in the theory of Earth expansion . Another theory is that the mantle flows neither in cells nor large plumes but rather as a series of channels just below Earth's crust, which then provide basal friction to the lithosphere. This theory, called "surge tectonics",
4810-593: 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
4940-488: Is to consider the relative rate at which each plate is moving as well as the evidence related to the significance of each process to the overall driving force on the plate. One of the most significant correlations discovered to date is that lithospheric plates attached to downgoing (subducting) plates move much faster than other types of plates. The Pacific plate, for instance, is essentially surrounded by zones of subduction (the so-called Ring of Fire) and moves much faster than
5070-407: Is typically 100 km (62 mi) thick. Its thickness is a function of its age. As time passes, it cools by conducting heat from below, and releasing it raditively into space. The adjacent mantle below is cooled by this process and added to its base. Because it is formed at mid-ocean ridges and spreads outwards, its thickness is therefore a function of its distance from the mid-ocean ridge where it
5200-435: Is used. It asserts that super plumes rise from the deeper mantle and are the drivers or substitutes of the major convection cells. These ideas find their roots in the early 1930s in the works of Beloussov and van Bemmelen , which were initially opposed to plate tectonics and placed the mechanism in a fixed frame of vertical movements. Van Bemmelen later modified the concept in his "Undation Models" and used "Mantle Blisters" as
5330-532: 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
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5460-567: The Appalachian Mountains of North America are very similar in structure and lithology . However, his ideas were not taken seriously by many geologists, who pointed out that there was no apparent mechanism for continental drift. Specifically, they did not see how continental rock could plow through the much denser rock that makes up oceanic crust. Wegener could not explain the force that drove continental drift, and his vindication did not come until after his death in 1930. As it
5590-463: 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
5720-602: 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
5850-589: 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
5980-529: 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
6110-704: 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
6240-463: 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
6370-422: The chemical subdivision of these same layers into the mantle (comprising both the asthenosphere and the mantle portion of the lithosphere) and the crust: a given piece of mantle may be part of the lithosphere or the asthenosphere at different times depending on its temperature and pressure. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates , which ride on
6500-668: The fluid-like solid the asthenosphere . Plate motions range from 10 to 40 millimetres per year (0.4 to 1.6 in/year) at the Mid-Atlantic Ridge (about as fast as fingernails grow), to about 160 millimetres per year (6.3 in/year) for the Nazca plate (about as fast as hair grows). Tectonic lithosphere plates consist of lithospheric mantle overlain by one or two types of crustal material: oceanic crust (in older texts called sima from silicon and magnesium ) and continental crust ( sial from silicon and aluminium ). The distinction between oceanic crust and continental crust
6630-473: The lithosphere and asthenosphere . The division is based on differences in mechanical properties and in the method for the transfer of heat . The lithosphere is cooler and more rigid, while the asthenosphere is hotter and flows more easily. In terms of heat transfer, the lithosphere loses heat by conduction , whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. This division should not be confused with
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#17327721764476760-534: 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 was governed as an independent commonwealth under the native parliament,
6890-619: 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
7020-621: 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
7150-644: 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 ,
7280-598: The Earth's rotation and the Moon as main driving forces for the plates. The vector of a plate's motion is a function of all the forces acting on the plate; however, therein lies the problem regarding the degree to which each process contributes to the overall motion of each tectonic plate. The diversity of geodynamic settings and the properties of each plate result from the impact of the various processes actively driving each individual plate. One method of dealing with this problem
7410-699: 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
7540-700: 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
7670-541: The actual motions of the Pacific plate and other plates associated with the East Pacific Rise do not correlate mainly with either slab pull or slab push, but rather with a mantle convection upwelling whose horizontal spreading along the bases of the various plates drives them along via viscosity-related traction forces. The driving forces of plate motion continue to be active subjects of on-going research within geophysics and tectonophysics . The development of
7800-478: The assumption of a solid Earth made these various proposals difficult to accept. The discovery of radioactivity and its associated heating properties in 1895 prompted a re-examination of the apparent age of Earth . This had previously been estimated by its cooling rate under the assumption that Earth's surface radiated like a black body . Those calculations had implied that, even if it started at red heat , Earth would have dropped to its present temperature in
7930-399: The asthenosphere. This theory was launched by Arthur Holmes and some forerunners in the 1930s and was immediately recognized as the solution for the acceptance of the theory as originally discussed in the papers of Alfred Wegener in the early years of the 20th century. However, despite its acceptance, it was long debated in the scientific community because the leading theory still envisaged
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#17327721764478060-476: The base of the lithosphere. Slab pull is therefore most widely thought to be the greatest force acting on the plates. In this understanding, plate motion is mostly driven by the weight of cold, dense plates sinking into the mantle at trenches. Recent models indicate that trench suction plays an important role as well. However, the fact that the North American plate is nowhere being subducted, although it
8190-495: The bathymetry of the deep ocean floors and the nature of the oceanic crust such as magnetic properties and, more generally, with the development of marine geology which gave evidence for the association of seafloor spreading along the mid-oceanic ridges and magnetic field reversals , published between 1959 and 1963 by Heezen, Dietz, Hess, Mason, Vine & Matthews, and Morley. Simultaneous advances in early seismic imaging techniques in and around Wadati–Benioff zones along
8320-416: The concept of continental drift , an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics . Tectonic plates also occur in other planets and moons. Earth's lithosphere, the rigid outer shell of
8450-413: The concept was of continents plowing through oceanic crust. Therefore, Wegener later changed his position and asserted that convection currents are the main driving force of plate tectonics in the last edition of his book in 1929. However, in the plate tectonics context (accepted since the seafloor spreading proposals of Heezen, Hess, Dietz, Morley, Vine, and Matthews (see below) during the early 1960s),
8580-575: 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
8710-416: 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
8840-417: 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
8970-415: The deep mantle at subduction zones, providing most of the driving force for plate movement. The weakness of the asthenosphere allows the tectonic plates to move easily towards a subduction zone. For much of the first quarter of the 20th century, the leading theory of the driving force behind tectonic plate motions envisaged large scale convection currents in the upper mantle, which can be transmitted through
9100-534: The discussions treated in this section) or proposed as minor modulations within the overall plate tectonics model. In 1973, George W. Moore of the USGS and R. C. Bostrom presented evidence for a general westward drift of Earth's lithosphere with respect to the mantle, based on the steepness of the subduction zones (shallow dipping towards the east, steeply dipping towards the west). They concluded that tidal forces (the tidal lag or "friction") caused by Earth's rotation and
9230-466: The driving force for horizontal movements, invoking gravitational forces away from the regional crustal doming. The theories find resonance in the modern theories which envisage hot spots or mantle plumes which remain fixed and are overridden by oceanic and continental lithosphere plates over time and leave their traces in the geological record (though these phenomena are not invoked as real driving mechanisms, but rather as modulators). The mechanism
9360-428: The earthquake of 2008. There is also a swimming pool there called Laugasgarður which is the largest one in Iceland tied with Laugardalslaug which has two 50 m long swimming pools. Hveragarðurinn is a park with various hot springs and fumaroles and information boards providing explanations on the occurrence. In Lystigarðurinn Fossflöt , a park which was founded in 1983, a hydroelectric power station can be visited which
9490-527: 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,
9620-588: 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
9750-473: The final one in 1936), he noted how the east coast of South America and the west coast of Africa looked as if they were once attached. Wegener was not the first to note this ( Abraham Ortelius , Antonio Snider-Pellegrini , Eduard Suess , Roberto Mantovani and Frank Bursley Taylor preceded him just to mention a few), but he was the first to marshal significant fossil and paleo-topographical and climatological evidence to support this simple observation (and
9880-415: 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
10010-695: The forces acting upon it by the Moon are a driving force for plate tectonics. As Earth spins eastward beneath the Moon, the Moon's gravity ever so slightly pulls Earth's surface layer back westward, just as proposed by Alfred Wegener (see above). Since 1990 this theory is mainly advocated by Doglioni and co-workers ( Doglioni 1990 ), such as in a more recent 2006 study, where scientists reviewed and advocated these ideas. It has been suggested in Lovett (2006) that this observation may also explain why Venus and Mars have no plate tectonics, as Venus has no moon and Mars' moons are too small to have significant tidal effects on
10140-588: The geographical latitudinal and longitudinal grid of Earth itself. These systematic relations studies in the second half of the nineteenth century and the first half of the twentieth century underline exactly the opposite: that the plates had not moved in time, that the deformation grid was fixed with respect to Earth's equator and axis, and that gravitational driving forces were generally acting vertically and caused only local horizontal movements (the so-called pre-plate tectonic, "fixist theories"). Later studies (discussed below on this page), therefore, invoked many of
10270-471: 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
10400-718: The interiors of plates, and these have been variously attributed to internal plate deformation and to mantle plumes. Tectonic plates may include continental crust or oceanic crust, or both. For example, the African plate includes the continent and parts of the floor of the Atlantic and Indian Oceans. Some pieces of oceanic crust, known as ophiolites , failed to be subducted under continental crust at destructive plate boundaries; instead these oceanic crustal fragments were pushed upward and were preserved within continental crust. Three types of plate boundaries exist, characterized by
10530-482: 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
10660-527: 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
10790-440: 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
10920-621: 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
11050-415: 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
11180-412: The large scale convection cells) or secondary. The secondary mechanisms view plate motion driven by friction between the convection currents in the asthenosphere and the more rigid overlying lithosphere. This is due to the inflow of mantle material related to the downward pull on plates in subduction zones at ocean trenches. Slab pull may occur in a geodynamic setting where basal tractions continue to act on
11310-437: 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
11440-421: The lithosphere before it dives underneath an adjacent plate, producing a clear topographical feature that can offset, or at least affect, the influence of topographical ocean ridges. Mantle plumes and hot spots are also postulated to impinge on the underside of tectonic plates. Slab pull : Scientific opinion is that the asthenosphere is insufficiently competent or rigid to directly cause motion by friction along
11570-403: The lower mantle, there is a slight westward component in the motions of all the plates. They demonstrated though that the westward drift, seen only for the past 30 Ma, is attributed to the increased dominance of the steadily growing and accelerating Pacific plate. The debate is still open, and a recent paper by Hofmeister et al. (2022) revived the idea advocating again the interaction between
11700-405: The many geographical, geological, and biological continuities between continents. In 1912, the meteorologist Alfred Wegener described what he called continental drift, an idea that culminated fifty years later in the modern theory of plate tectonics. Wegener expanded his theory in his 1915 book The Origin of Continents and Oceans . Starting from the idea (also expressed by his forerunners) that
11830-429: The matching of the rock formations along these edges. Confirmation of their previous contiguous nature also came from the fossil plants Glossopteris and Gangamopteris , and the therapsid or mammal-like reptile Lystrosaurus , all widely distributed over South America, Africa, Antarctica, India, and Australia. The evidence for such an erstwhile joining of these continents was patent to field geologists working in
11960-568: The motion picture of the Atlantic region", processes that anticipated seafloor spreading and subduction . One of the first pieces of geophysical evidence that was used to support the movement of lithospheric plates came from paleomagnetism . This is based on the fact that rocks of different ages show a variable magnetic field direction, evidenced by studies since the mid–nineteenth century. The magnetic north and south poles reverse through time, and, especially important in paleotectonic studies,
12090-438: The motion. At a subduction zone the relatively cold, dense oceanic crust sinks down into the mantle, forming the downward convecting limb of a mantle cell , which is the strongest driver of plate motion. The relative importance and interaction of other proposed factors such as active convection, upwelling inside the mantle, and tidal drag of the Moon is still the subject of debate. The outer layers of Earth are divided into
12220-470: The north pole, and each continent, in fact, shows its own "polar wander path". During the late 1950s, it was successfully shown on two occasions that these data could show the validity of continental drift: by Keith Runcorn in a paper in 1956, and by Warren Carey in a symposium held in March 1956. The second piece of evidence in support of continental drift came during the late 1950s and early 60s from data on
12350-481: 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
12480-410: 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
12610-401: 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
12740-407: The oceanic crust is suggested to be in motion with the continents which caused the proposals related to Earth rotation to be reconsidered. In more recent literature, these driving forces are: Forces that are small and generally negligible are: For these mechanisms to be overall valid, systematic relationships should exist all over the globe between the orientation and kinematics of deformation and
12870-437: The oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust. Along convergent plate boundaries , the process of subduction carries the edge of one plate down under the other plate and into the mantle . This process reduces the total surface area (crust) of the Earth. The lost surface is balanced by the formation of new oceanic crust along divergent margins by seafloor spreading, keeping
13000-517: 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,
13130-589: The planet including the crust and upper mantle , is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault ): convergent , divergent , or transform . The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes , volcanic activity , mountain-building , and oceanic trench formation. Tectonic plates are composed of
13260-470: The planet. In a paper by it was suggested that, on the other hand, it can easily be observed that many plates are moving north and eastward, and that the dominantly westward motion of the Pacific Ocean basins derives simply from the eastward bias of the Pacific spreading center (which is not a predicted manifestation of such lunar forces). In the same paper the authors admit, however, that relative to
13390-399: The plate as it dives into the mantle (although perhaps to a greater extent acting on both the under and upper side of the slab). Furthermore, slabs that are broken off and sink into the mantle can cause viscous mantle forces driving plates through slab suction. In the theory of plume tectonics followed by numerous researchers during the 1990s, a modified concept of mantle convection currents
13520-426: The plates of the Atlantic basin, which are attached (perhaps one could say 'welded') to adjacent continents instead of subducting plates. It is thus thought that forces associated with the downgoing plate (slab pull and slab suction) are the driving forces which determine the motion of plates, except for those plates which are not being subducted. This view however has been contradicted by a recent study which found that
13650-408: The present continents once formed a single land mass (later called Pangaea ), Wegener suggested that these separated and drifted apart, likening them to "icebergs" of low density sial floating on a sea of denser sima . Supporting evidence for the idea came from the dove-tailing outlines of South America's east coast and Africa's west coast Antonio Snider-Pellegrini had drawn on his maps, and from
13780-459: The relationships recognized during this pre-plate tectonics period to support their theories (see reviews of these various mechanisms related to Earth rotation the work of van Dijk and collaborators). Of the many forces discussed above, tidal force is still highly debated and defended as a possible principal driving force of plate tectonics. The other forces are only used in global geodynamic models not using plate tectonics concepts (therefore beyond
13910-428: The relative position of the magnetic north pole varies through time. Initially, during the first half of the twentieth century, the latter phenomenon was explained by introducing what was called "polar wander" (see apparent polar wander ) (i.e., it was assumed that the north pole location had been shifting through time). An alternative explanation, though, was that the continents had moved (shifted and rotated) relative to
14040-399: The ridge). Cool oceanic lithosphere is significantly denser than the hot mantle material from which it is derived and so with increasing thickness it gradually subsides into the mantle to compensate the greater load. The result is a slight lateral incline with increased distance from the ridge axis. This force is regarded as a secondary force and is often referred to as " ridge push ". This is
14170-634: 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
14300-608: 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
14430-480: 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
14560-463: 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
14690-491: The southern hemisphere. The South African Alex du Toit put together a mass of such information in his 1937 publication Our Wandering Continents , and went further than Wegener in recognising the strong links between the Gondwana fragments. Wegener's work was initially not widely accepted, in part due to a lack of detailed evidence but mostly because of the lack of a reasonable physically supported mechanism. Earth might have
14820-481: The theory of plate tectonics was the scientific and cultural change which occurred during a period of 50 years of scientific debate. The event of the acceptance itself was a paradigm shift and can therefore be classified as a scientific revolution, now described as the Plate Tectonics Revolution . Around the start of the twentieth century, various theorists unsuccessfully attempted to explain
14950-502: The theory) and "fixists" (opponents). During the 1920s, 1930s and 1940s, the former reached important milestones proposing that convection currents might have driven the plate movements, and that spreading may have occurred below the sea within the oceanic crust. Concepts close to the elements of plate tectonics were proposed by geophysicists and geologists (both fixists and mobilists) like Vening-Meinesz, Holmes, and Umbgrove. In 1941, Otto Ampferer described, in his publication "Thoughts on
15080-476: The total surface area constant in a tectonic "conveyor belt". Tectonic plates are relatively rigid and float across the ductile asthenosphere beneath. Lateral density variations in the mantle result in convection currents, the slow creeping motion of Earth's solid mantle. At a seafloor spreading ridge , plates move away from the ridge, which is a topographic high, and the newly formed crust cools as it moves away, increasing its density and contributing to
15210-429: The trenches bounding many continental margins, together with many other geophysical (e.g., gravimetric) and geological observations, showed how the oceanic crust could disappear into the mantle, providing the mechanism to balance the extension of the ocean basins with shortening along its margins. All this evidence, both from the ocean floor and from the continental margins, made it clear around 1965 that continental drift
15340-567: The violent South Iceland earthquake of 1896. A fenced-off geothermal area in the town has numerous hot springs and fumaroles . Hveragerði contains a number of greenhouses and is a hotbed for Icelandic horticulture . To the south of Hveragerði, there is the small port of Þorlákshöfn , winter point of departure for the ferry to the Westman Islands . Water from hot springs has been used for heating in this area since 1929. Hveragerði had 121 inhabitants in 1940 and 399 in 1946. Hveragerði
15470-467: The way the plates move relative to each other. They are associated with different types of surface phenomena. The different types of plate boundaries are: Tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere . Dissipation of heat from the mantle is the original source of the energy required to drive plate tectonics through convection or large scale upwelling and doming. As
15600-550: 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,
15730-680: 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
15860-515: 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
15990-604: Was awarded municipal status ( kaupstaðuréttindi ) on 1 July 1987. In 1989 the town had 1.593 inhabitants. On 29 May 2008 people were injured and many buildings in Hveragerði and its surroundings were damaged by a M w 6.3 earthquake . Hveragerðiskirkja , a modern Protestant church, was built 1967–72. Listasafn Árnesinga is a museum of arts founded in 1963 where about 500 pieces of art are exhibited. The exhibition Skjálftinn 2008 in Sunnumörk shopping centre refers to
16120-483: Was built as early as 1902 beside the waterfall Reykjafoss . The local football club is Hamar , who play in Iceland's fourth tier. Hveragerði is twinned with: Iceland Iceland ( Icelandic : Ísland , pronounced [ˈistlant] ) is a Nordic island country between the North Atlantic and Arctic Oceans , on the Mid-Atlantic Ridge between North America and Europe . It
16250-531: Was feasible. The theory of plate tectonics was defined in a series of papers between 1965 and 1967. The theory revolutionized the Earth sciences, explaining a diverse range of geological phenomena and their implications in other studies such as paleogeography and paleobiology . In the late 19th and early 20th centuries, geologists assumed that Earth's major features were fixed, and that most geologic features such as basin development and mountain ranges could be explained by vertical crustal movement, described in what
16380-599: Was formed. For a typical distance that oceanic lithosphere must travel before being subducted, the thickness varies from about 6 km (4 mi) thick at mid-ocean ridges to greater than 100 km (62 mi) at subduction zones. For shorter or longer distances, the subduction zone, and therefore also the mean, thickness becomes smaller or larger, respectively. Continental lithosphere is typically about 200 km (120 mi) thick, though this varies considerably between basins, mountain ranges, and stable cratonic interiors of continents. The location where two plates meet
16510-558: 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
16640-424: Was observed early that although granite existed on continents, seafloor seemed to be composed of denser basalt , the prevailing concept during the first half of the twentieth century was that there were two types of crust, named "sial" (continental type crust) and "sima" (oceanic type crust). Furthermore, it was supposed that a static shell of strata was present under the continents. It therefore looked apparent that
16770-443: Was popularized during the 1980s and 1990s. Recent research, based on three-dimensional computer modelling, suggests that plate geometry is governed by a feedback between mantle convection patterns and the strength of the lithosphere. Forces related to gravity are invoked as secondary phenomena within the framework of a more general driving mechanism such as the various forms of mantle dynamics described above. In modern views, gravity
16900-575: Was supported in this by researchers such as Alex du Toit ). Furthermore, when the rock strata of the margins of separate continents are very similar it suggests that these rocks were formed in the same way, implying that they were joined initially. For instance, parts of Scotland and Ireland contain rocks very similar to those found in Newfoundland and New Brunswick . Furthermore, the Caledonian Mountains of Europe and parts of
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