Les frontières des plaques
Dossier réalisé pour Eduterre-IFE par Christine Cottard
Cette Création est mise à disposition sous un contrat Creative Commons.

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Informations techniques à respecter:
1) Dans "Calques" (ou "Données géographiques") : tout décocher.
2) Pour ouvrir un dossier cocher la case.
3) Un clic sur le nom du dossier permet d'afficher un texte.
Deux clics permettent de se rendre au lieu désiré.
4) Si le dossier contient différentes couches de données il y a un triangle blanc (ou un + ) devant il suffit alors de cliquer sur le triangle qui devient noir (ou sur le +, un - apparait alors) et les différentes données s'affichent .
Attention : ne jamais perdre le Nord.
4) Au fur et à mesure, décocher les données non utilisées.
5) En fermant Google Earth : ne pas enregistrer dans mes lieux préférés.
6) Ne pas tenir compte en bas de certaines pages de :

La tâche à accomplir
Repèrer les différents types de frontières des plaques lithosphériques.
Repèrer les différents types de reliefs formés dans les zones de frontières.
Rechercher le nom de chaque phènomène géologique correspondant aux différentes frontières.
ATTENTION : il faut penser à utiliser le lexique pour trouver le nom des phénomènes
et aussi... penser à décocher les données non utilisées.

Les frontières des plaques lithosphériques
La zone où deux plaques s'éloignent l'une de l'autre est appelée frontière divergente
La zone où deux plaques se rapprochent l'une de l'autre est appelée frontière convergente
Les différents mouvements peuvent aussi engendrer des failles
Dossier réalisé pour Eduterre - IFE à partir des données modifiées de l'USGS
Cette création est mise à disposition sous un contrat Creative Commons.

Frontières des plaques.kmz
La zone où deux plaques s'éloignent l'une de l'autre est appelée frontière divergente
La zone où deux plaques se rapprochent l'une de l'autre est appelée frontière convergente
Les différents mouvements peuvent aussi engendrer des failles
Dossier réalisé pour Eduterre - IFE à partir des données modifiées de l'USGS
Cette création est mise à disposition sous un contrat Creative Commons.

Frontières des plaques
La zone où deux plaques s'éloignent l'une de l'autre est appelée frontière divergente
La zone où deux plaques se rapprochent l'une de l'autre est appelée frontière convergente
Les différents mouvements peuvent aussi faire coulisser des zones, il y a alors formation de failles transformantes
Cette création est mise à disposition sous un contrat Creative Commons
.

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Diffuse

Divergent

Convergent

Transform

Plate Boundaries

legende

legende-frontieres

Noms des plaques
Dossier réalisé pour Eduterre - IFE à partir des données modifiées de l'USGS
Cette création est mise à disposition sous un contrat Creative Commons.

Plaque africaine

Plaque antartique

Plaque arabique

Plaque australienne

Plaque caraibe

Plaque de Cocos

Plaque eurasienne

Plaque indienne

Plaque nord américaine

Plaque de Nazca

Plaque d' Okhotsk

Plaque pacifique

Plaque philippine

Plaque sud-américaine

Les frontières convergentes
Repère et nomme les 2 types de reliefs formés dans les zones de frontières convergentes.
Décris et nomme pour chaque type de reliefs le phénomène qui leur a donné naissance.
Pense à utiliser le lexique!

Un relief sous marin
Le point "O" est situé au niveau d'une "grande ligne sombre" c'est un relief particulier .
Cliquer avec le bouton droit sur le trait rouge
puis sur " Afficher le profil d'élévation"
et
pour un repérage sur la ligne, déplacer la souris le long du profil d'élévation.
- Aide toi du lexique pour nommer ce relief.
- A quel type de frontière correspond ce type de relief?
- Recherche le long de quel autre continent ce relief est aussi présent.

Afficher une ligne
Dans " Edition " cliquer sur " afficher le profil d'élévation"
Pour un repérage sur la ligne, déplacer la souris le long du profil d'élévation

Sans titre - Repère

Relief sous marin particulier
Nomme ce relief sous-marin. Pense au lexique!

L'himalaya
A la frontière de quelles plaques se situe l'Himalaya? Quel est ce relief? Comment se nomme le phénomène qui a lieu au niveau des 2 plaques (qui a permis la formation de l'Himalaya) ?

Le Mont Everest
Cliquer avec le bouton droit sur le trait rouge
puis sur " Afficher le profil d'élévation"
et
pour un repérage sur la ligne, déplacer la souris le long du profil d'élévation.
- Repère l'altitude du Mont Everest

Mont Everest

Sans titre - Trajet

Les frontières divergentes
Repère et nomme les structures formées dans les zones de frontières divergentes.
Décris et nomme le phénomène qui leur a donné naissance.
Tu observeras le cas d'une dorsale océanique visible à l'air libre : l'Islande

L'Islande
L'islande est située aux frontières divergentes de 2 plaques , cette frontière est une dorsale océanique.
Que constates-tu sur l'âge des roches par rapport à la dorsale?

Quelles sont ces structures?
Au niveau des dorsales océaniques des structures particulières se forment, lesquelles?

Ages des roches
Que constates-tu sur l'âge des roches par rapport à la dorsale?

Le volcanisme

Iceland and Arctic Ocean

Iceland (western)

Snaefellsjökull
Western Iceland
Volcano types:
Stratovolcano
Pyroclastic cones
Summit Elev: 1448 m
Latitude: 64.80°N
Longitude: 23.78°W
Ice-clad Snaefellsjökull volcano anchors the western tip of the isolated Snaefellsnes Peninsula in western Iceland. Numerous pyroclastic cones dot the flanks of the 1448-m-high stratovolcano, the only large central volcano in this part of Iceland. Lower-flank craters produced basaltic lava flows and upper-flank craters intermediate-to-silicic material. Holocene lava flows extend to the sea over the entire western half of the volcano. Several Holocene silicic eruptions have originated from the summit crater. The latest dated eruption took place about 1750 years ago; several lava flows may be even younger.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Inst of Earth Sciences, Univ of Iceland

Helgrindur
Western Iceland
Volcano types:
Pyroclastic cones
Summit Elev: 647 m
Latitude: 64.87°N
Longitude: 23.25°W
Helgrindur (also known as Lysuhóll or Lysukard) is one of Iceland's smallest volcanic systems. It consists of a chain of small alkali olivine basaltic cinder cones and vents along a WNW-ESE line cutting across the central Snaefellsnes Peninsula in western Iceland. The slightly arcuate line of Quaternary vents extends to the northern coast of the peninsula. Helgrindur is the central of three volcanic systems occupying the peninsula. The latest eruption from Helgrindur is undated, but the volcanic field has been active during the Holocene.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Inst of Earth Sciences, Univ of Iceland

Ljósufjöll
Western Iceland
Volcano types:
Fissure vents
Cinder cones
Summit Elev: 1063 m
Latitude: 64.87°N
Longitude: 22.23°W
The Ljósufjöll volcanic system at the eastern end of the Snaefellsnes Peninsula is composed of a group of alkali olivine basaltic cinder cones and lava flows along short fissures on a roughly 90-km-long WNW-ESE line. The volcanic field is about 20-km wide at the eastern end and narrows to about 10-km width on the west. The Ljósufjöll volcanic field contains the largest outcrops of silicic rhyolitic and trachytic rocks in the Snaefellsnes volcanic zone, erupted during the mid-to-late Pleistocene. Youthful-looking cinder cones and lava flows with morphologically pristine surfaces as evidence of numerous eruptions during the Holocene. The latest eruption at Ljósufjöll post-dated the settlement of Iceland, and took place about 1000 years ago.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Inst of Earth Sciences, Univ of Iceland

Iceland (southwestern)

Reykjanes
Southwestern Iceland
Crater rows
Shield volcanoes
The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the volcanic system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions at Reykjaneshryggur dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula.

Krísuvík
Southwestern Iceland
Crater rows
Shield volcanoes
The Krísuvík volcanic system (also spelled Krysuvik) consists of a group of NE-SW-trending basaltic crater rows and small shield volcanoes cutting the central Reykjanes Peninsula west of Kleifarvatn lake. Several eruptions have taken place since the settlement of Iceland, including the eruption of a large lava flow from the Ogmundargigar crater row around the 12th century. The latest eruption at Krísuvík took place during the 14th century.

Brennisteinsfjöll
Southwestern Iceland
Crater rows
Shield volcanoes
The Brennisteinsfjöll volcanic system, located east of Kleifarvatn lake, consists of a series of NE-SW-trending crater rows and small shield volcanoes. Postglacial and historical basaltic lavas cover a wide area. An eruption in 1000 AD was dated by its occurrence at the time of a meeting of the Icelandic outdoor parliament at Thingvellier. The most recent eruption at Brennisteinsfjöll took place in the 14th century.

Hengill
The Hengill volcanic system, cutting through Thingvallavatn lake, consists of a series of NE-SW-trending fissure vents, crater rows, and small shield volcanoes occupying a strongly faulted graben. Hengill is the easternmost of a series of four closely spaced basaltic fissure systems that cut diagonally across the Reykjanes Peninsula and lies at the triple junction of the Reykjanes Peninsula volcanic zone, the Western volcanic zone, and the South Iceland seismic zone. Postglacial lava flows surface much of the volcanic system. The latest eruption was radiocarbon dated about 1900 years before present. An eruption in the Hellisheidi area once thought to have occurred around 1000 AD at the time of a meeting of the Icelandic parliament at Thingvellir is now known to have occurred at a vent about 5 km away in the Brennisteinsfjöll volcanic system. The high-temperature Nesjavellir geothermal area NE of the uplifted hyaloclastite ridge forming the Hengill central volcano and the Helllisheidi geothermal field SW of Hengill are major producers of geothermal energy for Reykjavik.

Grímsnes
Maar
Grímsnes is a relatively small volcanic system located SE of Thingvallavatn lake. The Grímsnes volcanic system is displaced about 15-20 km to the east of the other en echelon group of volcanic fields of the Western Volcanic Zone extending across the Reykjanes Peninsula. Grímsnes lava flows cover 54 sq km and were erupted from a group of 11 fissures that produced a series of NE-SW-trending crater rows. The eruptions of the basaltic Grímsnes lavas were considered to have been restricted to a relatively short interval between about 6500 and 5500 years ago, but later work showed that some of the lava flows were radiocarbon dated at between about 7400 and 8900 years ago.

Prestahnukur
Subglacial volcano
Fissure vents
The massive subglacial Prestahnukur volcano at the SW end of the Langjökull icecap has associated rift zones to the north and SW that have erupted during the Holocene. Hot springs are associated with the rhyolitic Prestahnukur central volcano. The classic Icelandic shield volcano Skjaldbreidur was formed at the southern end of the Prestahnukur volcanic system, between Thorsjökull glacier and Thingvallavatn lake. The broad, low-angle shield volcano produced more than 13 cu km of basaltic lava flows during the early Holocene. The smaller mid-Holocene Sköflungur lava shield lies immediately NE of Skjaldbreidur.

Hveravellir
Subglacial volcano
Caldera
The Hveravellir central volcano lies at the northern end of an active volcanic zone that extends to the NE from the Reykjanes Peninsula. Hveravellir central volcano occupies the NE half of the massive Langjökull icecap, east of the prominent Pleistocene table mountain, Erikskökull. A summit caldera lies beneath the ice. The Kjalhraun shield volcano east of Langjökull produced about 11 cu km of lava about 7800 years ago. Several small shield volcanoes have been constructed along flank fissure zones, producing postglacial lava flows that flank Langjökull on the northern, western, and eastern sides. One of the most prominent of these is a small shield volcano that was formed at the site of the massive Hallmundahraun lava flow, which covers about 240 sq km and was erupted about 950 AD. The Geysir thermal area, containing Iceland's largest geysers, lies in the Haukadalur basin, near the southern end of the lengthy fissure system extending from the Hveravellir central volcano.

Hofsjökull
Subglacial volcano
Calderas
Stratovolcano
Hofsjökull volcano lies along an east-west-trending area connecting the two principal rift zones of Iceland. It bridges the gap between the Reykjanes-Langjökull rift on the west, which terminates at Langjökull, and the eastern zone, which extends NE-ward across east-central Iceland. The roughly 7 x 11 km central caldera of Hofsjökull volcano lies beneath the western part of the massive Hofsjökull icecap. A small Holocene shield volcano is located at the SW margin of the icecap. Flank fissures north and east of the icecap have produced basaltic lava flows during the Holocene. Kerlingarfjöll, a glacially dissected, largely Pleistocene rhyolitic central volcano located SW of the Hofsjökull icecap, is considered part of the Hofsjökull volcanic system. Steep-sided Pleistocene rhyolitic lava domes and numerous hot springs occupy two calderas at the center of the 5 x 7 km wide complex. Fumarolic activity at Kerlingarfjöll, mostly concentrated in the center of the complex, is the most vigorous in Iceland.

Iceland (southern)

Vestmannaeyjar
Southern Iceland
Submarine volcanoes
Fissure vents
Pyroclastic cones
The mostly submarine Vestmannaeyjar volcanic system is the southernmost and youngest volcanic center of the eastern volcanic zone that cuts across east-central Iceland. It consists of a roughly 30 x 40 km group of basaltic volcanic islands and submarine cones occupying a shallow shelf off the south coast of Iceland. Vestmannaeyjar was the site of two of Iceland's most noted 20th-century eruptions. The new island of Surtsey grew from the ocean floor during 1963-67. The island of Heimaey, 20 km to the NE, was the site of dramatic eruptions in 1973 during which lava flows partially overran the town of Vestmannaeyjar and threatened its harbor. Several other volcanoes have erupted during historical time. Twenty-two postglacial eruption sites are known in the Vestmannaeyjar system, and all ten subaerial vents on Heimaey are of Holocene age.

Eyjafjallajökull
Southern Iceland
Stratovolcano
Caldera
Eyjafjallajökull (also known as Eyjafjöll) is located west of Katla volcano. Eyjafjallajökull consists of an E-W-trending, elongated ice-covered basaltic-andesite stratovolcano with a 2.5-km-wide summit caldera. Fissure-fed lava flows occur on both the eastern and western flanks of the volcano, but are more prominent on the western side. Although the 1666-m-high volcano has erupted during historical time, it has been less active than other volcanoes of Iceland's eastern volcanic zone, and relatively few Holocene lava flows are known. An intrusion beneath the south flank from July-December 1999 was accompanied by increased seismic activity and was constrained by tilt measurements, GPS-geodesy and InSAR. The last historical eruption of Eyjafjallajökull prior to an eruption in 2010 produced intermediate-to-silicic tephra from the central caldera during December 1821 to January 1823.

Katla
Southern Iceland
Caldera
Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is hidden beneath the Myrdalsjökull icecap. The subglacial basaltic-to-rhyolitic volcano is one of Iceland's most active and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods. A large 10 x 14 km subglacial caldera with a long axis in a NW-SE direction is up to 750 m deep. Its high point reaches 1380 m, and three major outlet glaciers have breached its rim. Although most historical eruptions have taken place from fissures inside the caldera, the Eldgjá fissure system, which extends about 60 km to the NE from the current ice margin towards Grímsvötn volcano, has been the source of major Holocene eruptions. An eruption from the Eldgjá fissure system about 934 AD produced a voluminous lava flow of about 18 cu km, one of the world's largest known Holocene lava flows. Katla has been the source of frequent subglacial basaltic explosive eruptions that have been among the largest tephra-producers in Iceland during historical time and has also produced numerous dacitic explosive eruptions during the Holocene.

Torfajökull
The Torfajökull central volcano, located north of Myrdalsjökull and south of Thorisvatn lake, is cut by a 12-km-wide caldera that formed during the Pleistocene. Torjajökull consists of the largest area of silicic and intermediate volcanism in Iceland; about 225 cu km of silicic extrusive rocks are exposed. The dominantly rhyolitic complex rises about 500 m above surrounding basaltic plains and is elongated in a WNW-ESE direction. Most rhyolitic lava flows were erupted subglacially, forming silicic hyaloclastites that form ridge and dome-shaped breccias. During postglacial times only a narrow fissure zone at the western end has been active, producing mostly silicic lava flows, lava domes, and tephras. The most recent silicic eruption produced the Hrafntinnuhraun lava flow about 900 AD. The fissure system is along trend with and was active at the same time as the basaltic Veidivötn fissure system of Bárdarbunga central volcano in 1477 AD. The small Torfajökull icecap lies mostly outside the SE rim of the caldera, which is the site of vigorous thermal activity over a broad area of 130-140 sq km.

Hekla
One of Iceland's most prominent and active volcanoes, Hekla lies near the southern end of the eastern rift zone. Hekla occupies a rift-transform junction, and has produced basaltic andesites, in contrast to the tholeiitic basalts typical of Icelandic rift zone volcanoes. Vatnafjöll, a 40-km-long, 9-km-wide group of basaltic fissures and crater rows immediately SE of Hekla forms a part of the Hekla-Vatnafjöll volcanic system. A 5.5-km-long fissure, Heklugjá, cuts across the 1491-m-high Hekla volcano and is often active along its full length during major eruptions. Repeated eruptions along this rift, which is oblique to most rifting structures in the eastern volcanic zone, are responsible for Hekla's elongated ENE-WSW profile. Frequent large silicic explosive eruptions during historical time have deposited tephra throughout Iceland, providing valuable time markers used to date eruptions from other Icelandic volcanoes. Hekla tephras are generally rich in fluorine and are consequently very hazardous to grazing animals. Extensive lava flows from Hekla's historical eruptions, which date back to 1104 AD, cover much of the volcano's flanks.

Iceland (northeastern)

Grímsvötn
Northeastern Iceland
Grímsvötn, Iceland's most frequently active volcano in historical time, lies largely beneath the vast Vatnajökull icecap. The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed. The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano. The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow during an eruption in 1783. The 15-cu-km basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system. Extensive crop damage and livestock losses caused a severe famine that resulted in the loss of one-fifth of the population of Iceland.

Bárdarbunga
Northeastern Iceland
The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.

Tungnafellsjökull
Northeastern Iceland
Calderas
The Tungnafellsjökull central volcano, located immediately NW of the massive Vatnajökull icecap, contains two calderas. One is largely filled by the Tungnafellsjökull glacier, and the other ice-free caldera located to the SE contains Pleistocene rhyolitic lavas. The 1535-m-high Tungnafellsjökull volcano is largely of Pleistocene age, but postglacial flank fissures on the NE side have produced young basalts. The Hágöngur central volcano to the SW is part of the Tungnafellsjökull volcanic system.

Kverkfjöll
Kverkfjöll is a large subglacial volcano at the NE end of the Vatnajökull icecap. Two elliptical ice-filled calderas, 8 x 5 km in diameter, have been identified. An associated fissure swarm can be traced 60 km to the NE. A half dozen ridges of subglacially erupted pillow lavas are now exposed and extend beyond the glacial icecap to the NE. Subglacial historical eruptions have been recorded since the mid-17th century. Several other historical eruptions once attributed to Kverkfjöll are now thought to have originated from Bárdarbunga volcano to the west.

Askja
Calderas
Askja is a large basaltic central volcano that forms the Dyngjufjöll massif. It is truncated by three overlapping calderas, the largest of which is 8 km wide and may have been produced primarily from subglacial ring-fracture eruptions rather than by subsidence. A major rhyolitic explosive eruption from Dyngjufjöll about 10,000 years ago was in part associated with the formation of Askja caldera. Many postglacial eruptions also occurred along the ring-fracture. A major explosive eruption on the SE caldera margin in 1875 was one of Iceland's largest during historical time. It resulted in the formation of a smaller 4.5-km-wide caldera, now filled by Öskjuvatn lake, that truncates the rim of the larger central caldera. The 100-km-long Askja fissure swarm, which includes the Sveinagja graben, is also related to the Askja volcanic system, as are several small shield volcanoes such as Kollatadyngja. Twentieth-century eruptions at Askja have produced lava flows from vents located mostly near Öskjuvatn lake.

Fremrinamur
Fremrinamur central volcano, NNE of Askja and SE of Myvatn lake, is a volcanic system that is being constructed over the basaltic Ketildyngja shield volcano. Associated fissure systems, including the Sveinar fissure, extend 130 km to the northern coast of Iceland. The Kerlingardyngja shield volcano to the south is also part of the Fremrinamur volcanic system and formed about 6000 years ago. Iceland's renowned Myvatn lake formed as a result of the eruption of the massive 70-km-long older Laxarhraun lava flow from Ketildyngja shield volcano about 3800 years ago. The latest eruption from Fremrinamur produced the Burfellshraun lava flow about 2500-3000 years ago.

Krafla
Maars
The Krafla central volcano, located NE of Myvatn lake, is a topographically indistinct 10-km-wide caldera that is cut by a N-S-trending fissure system. Eruption of a rhyolitic welded tuff about 100,000 years ago was associated with formation of the caldera. Krafla has been the source of many rifting and eruptive events during the Holocene, including two in historical time, during 1724-29 and 1975-84. The prominent Hverfjall and Ludent tuff rings east of Myvatn were erupted along the 100-km-long fissure system, which extends as far as the north coast of Iceland. Iceland's renowned Myvatn lake formed during the eruption of the older Laxarhraun lava flow from the Ketildyngja shield volcano of the Fremrinamur volcanic system about 3800 years before present (BP); its present shape is constrained by the roughly 2000 years BP younger Laxarhraun lava flow from the Krafla volcanic system. The abundant pseudocraters that form a prominent part of the Myvatn landscape were created when the younger Laxarhraun lava flow entered the lake.

Theistareykjarbunga
Shield volcano
The Holocene Theistareykjarbunga basaltic shield volcano (also known as Theistareykir) and its associated N-S fissure system extends from north of Myvatn lake to the northern coast of Iceland. The low, 564-m-high Theistareykjarbunga shield volcano is the northernmost subaerial volcanic system along the eastern volcanic zone of Iceland. The Theistareykjarbunga segment is dominated by the 30 cu km Storaviti shield volcano, which was formed slightly after deglaciation. The youngest dated eruption produced the Theistareykjahraun lava flow about 3000-2700 years ago.

Tjörnes Fracture Zone
North of Iceland
Submarine volcano
The offshore Tjörnes Fracture Zone is an oblique transform zone that separates the northern volcanic zone of Iceland from the Kolbeinsey Ridge, part of the Mid-Atlantic Ridge north of Iceland. A submarine eruption was reported during 1867-1868 at the SE part of the fissure system off the northern coast of Iceland along the Manareyjar Ridge immediately north of Manareyjar Island.
About Volcano Data |

Iceland (southeastern)

Öraefajökull
Southeastern Iceland
Öraefajökull, Iceland's highest peak, is a broad glacier-clad central volcano at the SE end of the Vatnajökull icecap. A 4 x 5 km subglacial caldera truncates the summit of the dominantly basaltic and rhyolitic volcano. The extensive summit icecap is drained through deep glacial valleys dissecting the SW-to-SE flanks of the volcano. The largest-volume volcano in Iceland, 2119-m-high Öraefajökull was mostly constructed during Pleistocene glacial and interglacial periods. Holocene activity has been dominated by explosive summit eruptions, although flank lava effusions have also occurred. A major silicic eruption in 1362 AD was Iceland's largest historical explosive eruption. It and another eruption during 1727-28 were accompanied by major jökulhlaups (glacier outburst floods) that caused property damage and fatalities.

North of Iceland

Kolbeinsey Ridge
North of Iceland
Submarine volcano
A submarine eruption was reported in 1372 near the Kolbeinsey Ridge NW of Grimsey Island. Kolbeinsey Island, the only subaerial expression of this portion of the Mid-Atlantic Ridge, is a small, rapidly eroding island that formed during the late-Pleistocene or Holocene. Dredged glass shards indicate submarine eruptive activity during the late-Pleistocene until at least 11,800 radiocarbon years ago. The island was 700 m long in 1616 AD, but had shrunk to 42 m long and 5 m high by 1985 and could be eroded below sea level in the early part of the 21st century. The Kolbeinsey Hydrothermal Field lies south of the island. Thorarinsson (1965) roughly plotted the location of the 1372 eruption at about 66 degrees 40 minutes North. Reidel et al. (2003) note that the location is uncertain, but could lie between the Kolbeinsey Ridge and Hóll Seamount. Other reports of submarine eruptions north of Iceland have an even more uncertain location (1755) or have been discredited (1783 and 1838).
About Volcano Data |
Smithsonian Volcano Information

Atlantic Ocean (Jan Mayen)

Jan Mayen
Jan Mayen Island (Northern Atlantic)
Cinder cones
Remote Jan Mayen Island, located in the Norwegian Sea along the Mid-Atlantic Ridge about 650 km NE of Iceland, consists of two volcanic complexes separated by a narrow isthmus. The large Beerenberg basaltic stratovolcano (Nord-Jan) forms the NE end of the 40-km-long island, which is ringed by high cliffs. Beerenberg is a large 2277-m-high glacier-covered stratovolcano with a 1-km-wide summit crater and numerous cinder cones that were erupted along flank fissures. It is composed primarily of basaltic lava flows with minor amounts of tephra. Historical eruptions at Beerenberg date back to the 18th century. The Sor-Jan group of pyroclastic cones and lava domes occupies the SW tip of Jan Mayen. The Holocene Sor-Jan cinder cones, tephra rings, and trachytic lava domes were erupted from short fissures with a NE-SW trend.
Smithsonian Volcano Information

Arctic Ocean

Unnamed
East Gakkel Ridge
Submarine volcano
Summit Elev: -3800 m
Longitude: 85.00°E
Two young volcanoes were discovered along the eastern part of the slow-spreading Gakkel Ridge during a bathymetric survey from a submarine in 1999. The westernmost volcano showed evidence of highly reflective, sediment-free surfaces and young faults overprinted by lava flows. During January-September 1999 global seismic networks detected an earthquake swarm corresponding to the approximate location of this volcano. The correlation between the locations of the earthquake epicenter locations and the strongly reflective, untectonized western volcano together with the volcanic character of the seismic record provided evidence that lava erupted on the East Gakkel Ridge within days to months prior to a May 1999 submarine survey (Edwards et al., 2001). Because 12-kHz sonars can penetrate through thin sediments covering acoustically reflective lavas, it is possible that no eruption occurred on Gakkel Ridge in 1999. Historical global seismic records indicate that this was the only earthquake swarm detected on the Gakkel Ridge in about 100 years.
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Lexique
Arc insulaire : ensemble d'îles (souvent volcaniques), réparties en un ou plusieurs alignements courbes dessinant des arcs.
Asthénosphère : couche de 700km d'épaissseur sur laquelle les plaques lithosphériques sont en mouvement, elle est moins rigide que la lithosphère.
Collision : phénomène ayant lieu lorsque 2 plaques lithosphériques continentales s'affrontent provoquant la formation de chaînes de montagnes
Cône volcanique : : relief formé par l'accumulation des matériaux émis par le volcan.
Cratère: cavité située au sommet du cône volcanique.
Faille : zone où des blocs rocheux se sont déplacés.
Dorsale océanique : zone sous marine à la limite des frontières divergentes des plaques.
Expansion océanique : phénomène permettant la formation de lithosphère océanique au niveau d'une dorsale océanique formant une frontière divergente.
Fosse océanique : relief sous marin allongé de grande profondeur (5000 à 10000 m).
Frontière convergente : : zone à la limite de 2 plaques qui se rapprochent.
Frontière divergente : zone à la limite de 2 plaques qui s'éloignent.
Lave : magma dégazé émis à la surface du globe terrestre.
Lithosphère : couche supeprficielle du globe terrestre très rigide: son épaisseur varie selon les endroits de quelques km à 150 km (environ).
Lithosphère océanique : couche formée au niveau des dorsales océaniques formant le "plancher" des océans.
Lithosphère continentale : couche formant les continents.
Magma : matière minérale provenant de la fusion plus ou moins partielle des roches composé de liquides, éléments solides et gaz dissous.
Plaque lithosphérique : vaste zone de la surface du globe constituée de lithosphère (couche trés rigide) et délimitée par des zones ("frontières") actives. L'épaisseur maximale des plaques est de 150km .
Point chaud : zone très profonde de température élévée permettant la fusion des roches, de cette zone, le magma moins dense remonte en surface.
Un point chaud est considéré comme fixe.
Roches volcaniques : roches issues du refroidissement d'une lave.
Subduction : phénomène ayant lieu lorsque une plaque de lithosphère océanique s'enfonce sous une plaque de lithosphère continentale.
Zone active : zone étroite de forte activité sismique et volcanique .

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Les animations montrent les 3 types de phénomènes qui ont lieu aux frontières des plaques.
Cliquer sur le lien suivant et télécharger l'animation pour le collège " tectonique v2" .
animation