Iceland hotspot

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Eruption at Krafla, 1984 Lava flow at Krafla, 1984.jpg
Eruption at Krafla, 1984
Active volcanic areas and systems in Iceland Volcanic system of Iceland-Map-en.svg
Active volcanic areas and systems in Iceland
Iceland Mid-Atlantic Ridge map.svg

The Iceland hotspot 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.

Contents

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). [1] About 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), [2] and several eruptions beneath ice caps, which have generated devastating glacial bursts, most recently in 2010 after 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 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.

Theories of causation

There is an ongoing discussion about whether the hotspot is caused by a deep mantle plume or originates at a much shallower depth. [3] Recently, seismic tomography studies have found seismic wave speed anomalies under Iceland, consistent with a hot conduit 100 km (62 mi) across that extends to the lower mantle. [4]

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. [5] Bijwaard and Spakman, however, believe the Icelandic plume does reach to the mantle, and therefore comes from the same source as Hawaii. [6] While the Hawaiian island chain and 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. [7]

Mantle plume theory

The Iceland plume 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. [8] In this framework, the volcanism of Iceland is attributed to this plume, according to the theory of W. Jason Morgan. [9]

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 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. [10] 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 the plume head may be greater than 1,000 km (620 mi) in diameter. [10] [11]

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, [12] and the later entrenchment of the plume material into the northern Mid-Atlantic Ridge following its formation. [10]

Geological history

According to 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. [13] : 73–74  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 the plume was linked to, and has perhaps contributed to, the breakup of [14] 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, [15] as 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. [16]

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 a part of the submarine volcanic system of mid-oceanic ridges. [17] 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. [13] : 74  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 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. [18] Some geologists have suggested that the Iceland plume could have been responsible for the Paleogene uplift of the Scandinavian Mountains by producing changes in the density of the lithosphere and asthenosphere during the opening of the North Atlantic. [19] 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. [20]

An extinct ridge exists in western Iceland, leading to the theory that the plume has shifted east with time. The oldest crust of Iceland is more than 20 million years old and was formed at an old oceanic spreading center in the Westfjords (Vestfirðir) region. [13] : 74  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 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 was initiated 3 million years ago, develops. [21] The reorganisation of the plate boundaries in Iceland has also been attributed to microplate tectonics, [18] and an independent Hreppar microplate exists.

Topography/bathymetry of the north Atlantic around Iceland N-Atlantic-topo.png
Topography/bathymetry of the north Atlantic around Iceland

Challenges to the plume model

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 a mantle plume at all, but that the volcanism there results from processes related to plate tectonics and is restricted to the upper mantle. [22] [3]

Subducted ocean plate

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. [18] This model, however, 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.

Upper mantle convection

Another model proposes that the upwelling in the Iceland region is driven by lateral temperature gradients between the suboceanic mantle and the neighbouring Greenland craton and therefore also restricted to the upper 200–300 km (120–190 mi) of the mantle. [23] 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.

Geophysical and geochemical observations

Information about the structure of Earth's deep interior can be acquired only indirectly by geophysical and geochemical methods. For 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.

Seismology

An important method for imaging large-scale structures in Earth's interior is seismic tomography, by which 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, 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 the mantle transition zone at roughly 600 km (370 mi) depth. [17] [24] [25] 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.

Geochemistry

Numerous studies have addressed 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 the basalt in subducted slabs and is more easily fusible than peridotite. [26] [27] 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 was about 100 °C (212 °F) greater than that of the source of mid-ocean ridge basalts. [28]

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 (3He) to helium-4 (4He) isotopes. The ratio of helium-3 and helium-4 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 3He to 4He is strongly correlated with mid ocean ridge eruptions due to its shallow source of mantle, while high ratios of 3He to 4He are correlated with ocean island basalts due to its deeper source of mantle. Both high and low ratios of 3He to 4He are found on Iceland. High ratios are associated with the western portion of the island, while lower ratios are associated with the eastern part of the island. [29] 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 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 is regarded to lie at about 150 parts per million. [30] [31] 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. [13] : 106 

Gravimetry/Geoid

The north Atlantic is characterized by strong, large-scale anomalies of the gravity field and 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. [32] Furthermore, the plume and the thickened crust cause a positive gravity anomaly of about 60 mGal (=0.0006 m/s²) (free-air).

Free-air gravity anomalies in the north Atlantic around Iceland. For better representation the color scale was limited to anomalies up to +80 mGal (+0.8 mm/s2). N-Atlantic-grav.png
Free-air gravity anomalies in the north Atlantic around Iceland. For better representation the color scale was limited to anomalies up to +80 mGal (+0.8 mm/s²).

Geodynamics

Since 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 the seismological and geochemical observations. [33] [34] 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). [13] : 71  Such temperatures have not yet been confirmed by petrology, however.

Magma Transportation Under Iceland

Understanding how magma is transported from great depths near the Moho discontinuity to the surface has implications for understanding 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. [35] 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, 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. [35]

See also

Related Research Articles

<span class="mw-page-title-main">Mantle plume</span> Upwelling of abnormally hot rock within Earths mantle

A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries.

<span class="mw-page-title-main">Hotspot (geology)</span> Volcanic region hotter than the surrounding mantle

In geology, hotspots are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii, Iceland, and Yellowstone hotspots. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them.

<span class="mw-page-title-main">Large igneous province</span> Huge regional accumulation of igneous rocks

A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive and extrusive, arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics. The formation of some of the LIPs in the past 500 million years coincide in time with mass extinctions and rapid climatic changes, which has led to numerous hypotheses about causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems.

<span class="mw-page-title-main">Geology of Iceland</span>

The geology of Iceland is unique and of particular interest to geologists. Iceland lies on the divergent boundary between the Eurasian Plate and the North American Plate. It also lies above a hotspot, the Iceland plume. The plume is believed to have caused the formation of Iceland itself, the island first appearing over the ocean surface about 16 to 18 million years ago. The result is an island characterized by repeated volcanism and geothermal phenomena such as geysers.

<span class="mw-page-title-main">East Australia hotspot</span>

The East Australia hotspot is a volcanic province in southeast Australia which includes the Peak Range in central Queensland, the Main Range on the Queensland-New South Wales border, Tweed Volcano in New South Wales, and the Newer Volcanics Province (NVP) in Victoria and South Australia. A number of the volcanoes in the province have erupted since Aboriginal settlement. The most recent eruptions were about 5,600 years ago, and memories of them survive in Aboriginal folklore. These eruptions formed the volcanoes Mount Schank and Mount Gambier in the NVP. There have been no eruptions on the Australian mainland since European settlement.

<span class="mw-page-title-main">Volcanic belt</span> Large volcanically active region

A volcanic belt is a large volcanically active region. Other terms are used for smaller areas of activity, such as volcanic fields or volcanic systems. Volcanic belts are found above zones of unusually high temperature where magma is created by partial melting of solid material in the Earth's crust and upper mantle. These areas usually form along tectonic plate boundaries at depths of 10 to 50 kilometres. For example, volcanoes in Mexico and western North America are mostly in volcanic belts, such as the Trans-Mexican Volcanic Belt that extends 900 kilometres (560 mi) from west to east across central-southern Mexico and the Northern Cordilleran Volcanic Province in western Canada. In the case of Iceland, the geologist G.G. Bárdarson in 1929 identified clusters of volcanic belts while studying the Reykjanes Peninsula.

<span class="mw-page-title-main">New England hotspot</span> Volcanic hotspot in the North Atlantic Ocean

The New England hotspot, also referred to as the Great Meteor hotspot and sometimes the Monteregian hotspot, is a volcanic hotspot in the North Atlantic Ocean. It created the Monteregian Hills intrusions in Montreal and Montérégie, the White Mountains intrusions in New Hampshire, the New England and Corner Rise seamounts off the coast of North America, and the Seewarte Seamounts east of the Mid-Atlantic Ridge on the African Plate, the latter of which include its most recent eruptive center, the Great Meteor Seamount. The New England, Great Meteor, or Monteregian hotspot track has been used to estimate the movement of the North American Plate away from the African Plate from the early Cretaceous period to the present using the fixed hotspot reference frame.

<span class="mw-page-title-main">Azores hotspot</span> Volcanic hotspot at the Azores

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<span class="mw-page-title-main">Eifel hotspot</span> Volcanic hotspot in Western Germany

The Eifel hotspot is a volcanic hotspot in Western Germany. It is one of many recent volcanic formations in and around the Eifel mountain range and includes the volcanic field known as Volcanic Eifel. Although the last eruption occurred around 10,000 years ago, the presence of escaping volcanic gases in the region indicates that it is still weakly active.

<span class="mw-page-title-main">Marquesas hotspot</span> Volcanic hotspot in the Pacific Ocean

The Marquesas hotspot is a volcanic hotspot in the southern Pacific Ocean. It is responsible for the creation of the Marquesas Islands – a group of eight main islands and several smaller ones – and a few seamounts. The islands and seamounts formed between 5.5 and 0.4 million years ago and constitute the northernmost volcanic chain in French Polynesia.

<span class="mw-page-title-main">North Atlantic Igneous Province</span> Large igneous province in the North Atlantic, centered on Iceland

The North Atlantic Igneous Province (NAIP) is a large igneous province in the North Atlantic, centered on Iceland. In the Paleogene, the province formed the Thulean Plateau, a large basaltic lava plain, which extended over at least 1.3 million km2 (500 thousand sq mi) in area and 6.6 million km3 (1.6 million cu mi) in volume. The plateau was broken up during the opening of the North Atlantic Ocean leaving remnants preserved in north Ireland, west Scotland, the Faroe Islands, northwest Iceland, east Greenland, western Norway and many of the islands located in the north eastern portion of the North Atlantic Ocean. The igneous province is the origin of the Giant's Causeway and Fingal's Cave. The province is also known as Brito–Arctic province and the portion of the province in the British Isles is also called the British Tertiary Volcanic Province or British Tertiary Igneous Province.

<span class="mw-page-title-main">Society hotspot</span> Pacific volcanic hotspot

The Society hotspot is a volcanic hotspot in the south Pacific Ocean which is responsible for the formation of the Society Islands, an archipelago of fourteen volcanic islands and atolls spanning around 720 kilometres (450 mi) of the ocean which formed between 4.5 and <1 Ma.

<span class="mw-page-title-main">Ocean island basalt</span> Volcanic rock

Ocean island basalt (OIB) is a volcanic rock, usually basaltic in composition, erupted in oceans away from tectonic plate boundaries. Although ocean island basaltic magma is mainly erupted as basalt lava, the basaltic magma is sometimes modified by igneous differentiation to produce a range of other volcanic rock types, for example, rhyolite in Iceland, and phonolite and trachyte at the intraplate volcano Fernando de Noronha. Unlike mid-ocean ridge basalts (MORBs), which erupt at spreading centers (divergent plate boundaries), and volcanic arc lavas, which erupt at subduction zones (convergent plate boundaries), ocean island basalts are the result of intraplate volcanism. However, some ocean island basalt locations coincide with plate boundaries like Iceland, which sits on top of a mid-ocean ridge, and Samoa, which is located near a subduction zone.

The Erebus hotspot is a volcanic hotspot responsible for the high volcanic activity on Ross Island in the western Ross Sea of Antarctica. Its current eruptive zone, Mount Erebus, has erupted continuously since its discovery in 1841. Magmas of the Erebus hotspot are similar to those erupted from hotspots at the active East African Rift in eastern Africa. Mount Bird at the northernmost end of Ross Island and Mount Terror at its eastern end are large basaltic shield volcanoes that have been potassium-argon dated 3.8–4.8 and 0.8–1.8 million years old.

<span class="mw-page-title-main">Geology of Cape Verde</span>

Cape Verde is a volcanic archipelago situated above an oceanic rise that puts the base of the islands 2 kilometers (1.2 mi) above the rest of the seafloor. Cape Verde has been identified as a hotspot and the majority of geoscientists have argued that the archipelago is underlain by a mantle plume and that this plume is responsible for the volcanic activity and associated geothermal anomalies.

<span class="mw-page-title-main">Opening of the North Atlantic Ocean</span> Breakup of Pangea

The opening of the North Atlantic Ocean is a geological event that has occurred over millions of years, during which the supercontinent Pangea broke up. As modern-day Europe and North America separated during the final breakup of Pangea in the early Cenozoic Era, they formed the North Atlantic Ocean. Geologists believe the breakup occurred either due to primary processes of the Iceland plume or secondary processes of lithospheric extension from plate tectonics.

The Discovery Seamounts are a chain of seamounts in the Southern Atlantic Ocean, including Discovery Seamount. The seamounts are 850 kilometres (530 mi) east of Gough Island and once formed islands. Various volcanic rocks as well as glacial dropstones and sediments have been dredged from the Discovery Seamounts.

<span class="mw-page-title-main">Noronha hotspot</span>

Noronha hotspot is a hypothesized hotspot in the Atlantic Ocean. It has been proposed as the candidate source for volcanism in the Fernando de Noronha archipelago of Brazil, as well as of other volcanoes also in Brazil and even the Bahamas and the Central Atlantic Magmatic Province.

<span class="mw-page-title-main">Plate theory (volcanism)</span> Model of volcanic activities on Earth

The plate theory is a model of volcanism that attributes all volcanic activity on Earth, even that which appears superficially to be anomalous, to the operation of plate tectonics. According to the plate theory, the principal cause of volcanism is extension of the lithosphere. Extension of the lithosphere is a function of the lithospheric stress field. The global distribution of volcanic activity at a given time reflects the contemporaneous lithospheric stress field, and changes in the spatial and temporal distribution of volcanoes reflect changes in the stress field. The main factors governing the evolution of the stress field are:

  1. Changes in the configuration of plate boundaries.
  2. Vertical motions.
  3. Thermal contraction.

Intraplate volcanism is volcanism that takes place away from the margins of tectonic plates. Most volcanic activity takes place on plate margins, and there is broad consensus among geologists that this activity is explained well by the theory of plate tectonics. However, the origins of volcanic activity within plates remains controversial.

References

Notes

  1. ↑ "Hversu mörg eldgos hafa verið á Íslandi síðustu fimmtíu árin?". Vísindavefurinn (in Icelandic).
  2. ↑ Bindeman, Ilya; Gurenko, Andrey; Sigmarsson, Olgeir; Chaussidon, Marc (1 September 2008). "Oxygen isotope heterogeneity and disequilibria of olivine crystals in large volume Holocene basalts from Iceland: Evidence for magmatic digestion and erosion of Pleistocene hyaloclastites". Geochimica et Cosmochimica Acta. 72 (17): 4397–4420. Bibcode:2008GeCoA..72.4397B. doi:10.1016/j.gca.2008.06.010.
  3. 1 2 Foulger, G. R. (8 February 2005). "Iceland & the North Atlantic Igneous Province". MantlePlumes.org. Retrieved 2008-03-22.
  4. ↑ Rickers, Florian; Fichtner, Andreas; Trampert, Jeannot (1 April 2013). "The Iceland–Jan Mayen plume system and its impact on mantle dynamics in the North Atlantic region: Evidence from full-waveform inversion". Earth and Planetary Science Letters. 367: 39–51. Bibcode:2013E&PSL.367...39R. doi: 10.1016/j.epsl.2013.02.022 . hdl: 20.500.11850/77780 .
  5. ↑ Foulger, G. R.; Pritchard, M. J.; Julian, B. R.; Evans, J. R. (1 September 2000). "The seismic anomaly beneath Iceland extends down to the mantle transition zone and no deeper". academic.oup.com. pp. F1–F5.
  6. ↑ Bijwaard, Harmen; Spakman, Wim (15 March 1999). "Tomographic evidence for a narrow whole mantle plume below Iceland". Earth and Planetary Science Letters. 166 (3–4): 121–126. Bibcode:1999E&PSL.166..121B. doi:10.1016/S0012-821X(99)00004-7.
  7. ↑ Morgan, W. Jason; Morgan, Jason Phipps (2009). "Plate velocities in hotspot reference frame: electronic supplement" (PDF). In Foulger, Gillian R.; Jurdy, Donna M. (eds.). Plates, Plumes, and Planetary Processes (P4).
  8. ↑ Ritsema, J.; Van Heijst, H. J.; Woodhouse, J. H. (1999). "Complex shear wave velocity structure imaged beneath Africa and Iceland". Science . 286 (5446): 1925–1928. doi:10.1126/science.286.5446.1925. PMID   10583949. S2CID   46160705.
  9. ↑ Morgan, W. J. (1971). "Convection Plumes in the Lower Mantle". Nature . 230 (5288): 42–43. Bibcode:1971Natur.230...42M. doi:10.1038/230042a0. S2CID   4145715.
  10. 1 2 3 Howell, Samuel M.; Ito, Garrett; Breivik, Asbjørn J.; Rai, Abhishek; Mjelde, Rolf; Hanan, Barry; Sayit, Kaan; Vogt, Peter (15 April 2014). "The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day". Earth and Planetary Science Letters. 392: 143–153. Bibcode:2014E&PSL.392..143H. doi:10.1016/j.epsl.2014.02.020. hdl: 10125/41133 .
  11. ↑ Dordevic, Mladen; Georgen, Jennifer (1 January 2016). "Dynamics of plume–triple junction interaction: Results from a series of three-dimensional numerical models and implications for the formation of oceanic plateaus". Journal of Geophysical Research: Solid Earth. 121 (3): 2014JB011869. Bibcode:2016JGRB..121.1316D. doi: 10.1002/2014JB011869 . ISSN   2169-9356.
  12. ↑ Mihalffy, Peter; Steinberger, Bernhard; Schmeling, Harro (1 February 2008). "The effect of the large-scale mantle flow field on the Iceland hotspot track". Tectonophysics. Plate movement and crustal processes in and around Iceland. 447 (1–4): 5–18. Bibcode:2008Tectp.447....5M. doi:10.1016/j.tecto.2006.12.012.
  13. 1 2 3 4 5 Ruedas, Thomas; Marquart, Gabriele; Schmeling, Harro (2007). "Iceland: The current picture of a ridge-centred mantle plume". In Ritter, Joachim R. R.; Christensen, Ulrich R. (eds.). Mantle Plumes: A multidisciplinary approach. Springer. pp. 71–126. doi:10.1007/978-3-540-68046-8_3. ISBN   9783540680451.
  14. ↑ White, R.; McKenzie, D. (1989). "Magmatism at rift zones: The generation of volcanic continental margins and flood basalts". Journal of Geophysical Research: Solid Earth . 94 (B6): 7685. Bibcode:1989JGR....94.7685W. doi:10.1029/JB094iB06p07685.
  15. ↑ Lawver, L. A.; Muller, R. D. (1994). "Iceland hotspot track". Geology . 22 (4): 311–314. Bibcode:1994Geo....22..311L. doi:10.1130/0091-7613(1994)022<0311:IHT>2.3.CO;2.
  16. ↑ Forsyth, D. A.; Morel-A-L'Huissier, P.; Asudeh, I.; Green, A. G. (1986). "Alpha Ridge and iceland-products of the same plume?". Journal of Geodynamics . 6 (1–4): 197–214. Bibcode:1986JGeo....6..197F. doi:10.1016/0264-3707(86)90039-6.
  17. 1 2 Wolfe, C. J.; Bjarnason, I. Th.; VanDecar, J. C.; Solomon, S. C. (1997). "Seismic structure of the Iceland mantle plume". Nature . 385 (6613): 245–247. Bibcode:1997Natur.385..245W. doi:10.1038/385245a0. S2CID   4353383.
  18. 1 2 3 Foulger, G. R.; Anderson, D. L. (2005). "A cool model for the Iceland hotspot". Journal of Volcanology and Geothermal Research . 141 (1–2): 1–22. Bibcode:2005JVGR..141....1F. doi:10.1016/j.jvolgeores.2004.10.007.
  19. ↑ Nielsen, S. B.; et al. (2002). "Paleocene initiation of Cenozoic uplift in Norway". In Doré, A. G.; Cartwright, J. A.; Stoker, M. S.; Turner, J. P.; White, N. (eds.). Exhumation of the North Atlantic Margin: Timing, Mechanisms and Implications for Petroleum Exploration. Geological Society, London, Special Publications. Vol. 196. Geological Society of London. pp. 103–116. Bibcode:2002GSLSP.196...45N. doi:10.1144/GSL.SP.2002.196.01.04. S2CID   128675048.
  20. ↑ Gale, Andrew S.; Lovell, Bryan (2018). "Proceedings of the Geologists' Association". The Cretaceous–Paleogene Unconformity in England: Uplift and Erosion Related to the Iceland Mantle Plume. 129 (3): 421–435. doi:10.1016/j.pgeola.2017.04.002. S2CID   133817989.
  21. ↑ Sæmundsson, K. (1979). "Outline of the geology of Iceland" (PDF). Jökull . 29: 7–28. doi:10.33799/jokull1979.29.007. S2CID   257227875.
  22. ↑ Foulger, G. R. (2010). Plates vs. Plumes: A Geological Controversy. Wiley-Blackwell. ISBN   978-1-4051-6148-0.
  23. ↑ King, S. D.; Anderson, D. L. (1995). "An alternative mechanism of flood basalt formation". Earth and Planetary Science Letters . 136 (3–4): 269–279. Bibcode:1995E&PSL.136..269K. doi:10.1016/0012-821X(95)00205-Q.
  24. ↑ Allen, R. M; et al. (2002). "Imaging the mantle beneath Iceland using integrated seismological techniques". Journal of Geophysical Research: Solid Earth . 107 (B12): ESE 3-1–ESE 3-16. Bibcode:2002JGRB..107.2325A. doi: 10.1029/2001JB000595 .
  25. ↑ Foulger, G. R; et al. (2001). "Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle". Geophysical Journal International . 146 (2): 504–530. Bibcode:2001GeoJI.146..504F. doi: 10.1046/j.0956-540x.2001.01470.x .
  26. ↑ Thirlwall, M. F. (1995). "Generation of the Pb isotopic characteristics of the Iceland plume". Journal of the Geological Society . 152 (6): 991–996. Bibcode:1995JGSoc.152..991T. doi:10.1144/GSL.JGS.1995.152.01.19. S2CID   130291755.
  27. ↑ Murton, B. J. (2002). "Plume-Ridge Interaction: A Geochemical Perspective from the Reykjanes Ridge". Journal of Petrology . 43 (11): 1987–2012. Bibcode:2002JPet...43.1987M. doi: 10.1093/petrology/43.11.1987 .
  28. ↑ Herzberg, C.; et al. (2007). "Temperatures in ambient mantle and plumes: Constraints from basalts, picrites, and komatiites". Geochemistry, Geophysics, Geosystems . 8 (2): Q02006. Bibcode:2007GGG.....8.2006H. doi: 10.1029/2006GC001390 . hdl: 20.500.11820/adec2586-1b4f-4a63-8cc2-b4b3159e2729 .
  29. ↑ Harðardóttir, Sunna; Halldórsson, Sæmundur Ari; Hilton, David R. (2018). "Spatial Distribution of Helium Isotopes in Icelandic Geothermal Fluids and Volcanic Materials with Implications for Location, Upwelling and Evolution of the Icelandic Mantle Plume". Chemical Geology. 480: 12–27. Bibcode:2018ChGeo.480...12H. doi:10.1016/j.chemgeo.2017.05.012.
  30. ↑ Jamtveit, B.; Brooker, R.; Brooks, K.; Larsen, L. M.; Pedersen, T. (2001). "The water content of olivines from the North Atlantic Volcanic Province". Earth and Planetary Science Letters . 186 (3–4): 401. Bibcode:2001E&PSL.186..401J. doi:10.1016/S0012-821X(01)00256-4.
  31. ↑ Nichols, A. R. L.; Carroll, M. R.; Höskuldsson, Á. (2002). "Is the Iceland hot spot also wet? Evidence from the water contents of undegassed submarine and subglacial pillow basalts". Earth and Planetary Science Letters . 202 (1): 77. Bibcode:2002E&PSL.202...77N. doi:10.1016/S0012-821X(02)00758-6.
  32. ↑ Marquart, G. (2001). "On the geometry of mantle flow beneath drifting lithospheric plates". Geophysical Journal International . 144 (2): 356–372. Bibcode:2001GeoJI.144..356M. doi: 10.1046/j.0956-540X.2000.01325.x .
  33. ↑ Ribe, N. M.; Christensen, U. R.; Theißing, J. (1995). "The dynamics of plume-ridge interaction, 1: Ridge-centered plumes". Earth and Planetary Science Letters . 134 (1): 155. Bibcode:1995E&PSL.134..155R. doi:10.1016/0012-821X(95)00116-T.
  34. ↑ Ito, G.; Lin, J.; Gable, C. W. (1996). "Dynamics of mantle flow and melting at a ridge-centered hotspot: Iceland and the Mid-Atlantic Ridge". Earth and Planetary Science Letters . 144 (1–2): 53. Bibcode:1996E&PSL.144...53I. doi:10.1016/0012-821X(96)00151-3.
  35. 1 2 Mutch, E.J.F.; Maclennan, J.; Shorttle, O.; Edmonds, M.; Rudge, J.F. (2019). "Rapid transcrustal magma movement under Iceland". Nature Geoscience. 12 (7): 569–574. Bibcode:2019NatGe..12..569M. doi:10.1038/s41561-019-0376-9.

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