Langjökull
Encyclopedia
Langjökull is the second largest ice cap
Ice cap
An ice cap is an ice mass that covers less than 50 000 km² of land area . Masses of ice covering more than 50 000 km² are termed an ice sheet....

 in Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 (953 km2), after Vatnajökull
Vatnajökull
Vatnajökull is the largest glacier in Iceland. It is located in the south-east of the island, covering more than 8% of the country.-Size:With an area of 8,100 km², Vatnajökull is the largest ice cap in Europe by volume and the second largest in area Vatnajökull is the largest glacier in...

. It is situated in the west of the Icelandic interior or Highlands of Iceland
Highlands of Iceland
The Highlands of Iceland cover most of the interior of Iceland. They are situated above 400–500 metres and are mostly an uninhabitable volcanic desert, because the water precipitating as rain or snow infiltrates so quickly into the ground that it is unavailable for plant growth, which results...

 and can be seen clearly from Haukadalur
Haukadalur
-Haukadalur, Golden Circle:This valley lies to the north of the Laugarvatn in the south of Iceland at .There are to be seen some of the most famous sights of the island: the geysers and other geothermal features which have developed on Laugarfjall rhyolitic dome. The biggest geysers of Haukadalur...

.

The glacier is located at 64°45′N 19°59′W.

Its volume is 195 km³ and the ice is up to 580 m (1,902.9 ft) thick. The highest point of the ice cap (at Baldjökull at the northern end of Langjökull) is about 1450 m (4,757.2 ft) above sea level.

In the past, the largest recorded surface area was in 1840.

Situation and form

The glacier is roughly parallel to the direction of the country's active volcanic zone (see volcanism in Iceland): north-east to south-west. It is about 50 km (31.1 mi) long and 15 kilometre wide, and has a slightly narrower point roughly between the lake Hvítárvatn
Hvítárvatn
Hvítárvatn is a lake in the Highlands of Iceland and the source of glacial river Hvítá. It is located 45 km northeast of Gullfoss. Its surface is about 30 km²; its greatest depth is 84 m....

 on the Kjölur
Kjölur
The Kjölur is a highland road in Iceland. It is the second longest of the roads through the Highlands of Iceland. It takes about 5 hours to traverse by car.- Geography :...

 mountain road to the east and the Þrístapajökull glacier to the west, near another smaller glacier, Eiríksjökull
Eiríksjökull
Eiríksjökull is a glacier north-west of Langjökull in Iceland, with an area of reaching a height of , making it the largest table mountain in Iceland. Rising over above its surrounding, the lowest of a hyaloclastite tuya formed presumably by a single subglacial volcanic activity is capped by a...

, which is not quite connected to Langjökull. It is the nearest large glacier to Reykjavík
Reykjavík
Reykjavík is the capital and largest city in Iceland.Its latitude at 64°08' N makes it the world's northernmost capital of a sovereign state. It is located in southwestern Iceland, on the southern shore of Faxaflói Bay...

.

The area of the glacier includes some mountains, e.g. Jarlhettur ("The earl's hat") on the east side of Langjökull, a palagonitic
Palagonite
Palagonite is an alteration product from the interaction of water with volcanic glass of chemical composition similar to basalt. Palagonite can also result from the interaction between water and basalt melt...

 mountain range, which originated in a fissure eruption under a glacier during Ice Age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

.

The mountain Skríðufell (1235 m (4,051.8 ft)) is situated on the east, above lake Hvítárvatn
Hvítárvatn
Hvítárvatn is a lake in the Highlands of Iceland and the source of glacial river Hvítá. It is located 45 km northeast of Gullfoss. Its surface is about 30 km²; its greatest depth is 84 m....

. Other mountains on the eastern side of Langjökull are Fjallkirkja (1177 m (3,861.5 ft)), Þursaborg ({convert|1290|m|abbr=on}}) and Péturshorn (1370 m (4,494.8 ft)).

A little to the east of Fjallkirkja is the hut of the Icelandic Glacier Research Society (Jöklarannsóknarfélag), which includes scientists as well as interested amateurs.

Glaciers in the area

A number of outlet glaciers reach down from Langjökull to the valleys and plains below. These include Norður- and Suðurjökull to the east; Vestri- and Eystri-Hagafellsjökull at the southern end of Langjökull which are separated by the mountain Hagafell; and Þrístapajökull to the west. Geitlandsjökull
Geitlandsjökull
Geitlandsjökull is a lateral glacier of Langjökull, the second largest ice cap in Iceland , in the west of Iceland. The highest point of Geitlandsjökull, which lies on top of a tuya, reaches a height of 1,400 m....

 (1395m) is an outpost to the southwest, a glacier covering a tuya
Tuya
A tuya is a type of distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are somewhat rare worldwide, being confined to regions which were covered by glaciers and also had active volcanism during the same time period.-Formation:Tuyas are...

 which is connected to Langjökull.

Research shows that the outlet glaciers Norður- and Suðurjökull reached as far as lake Hvítárvatn until about 1900 but have retreated rapidly since then
.

Water flow and development of the glacier

Despite the size of Langjökull, not many rivers directly originate there. However research has shown that large quantities of water flow in sub-surface streams to lake Þingvallavatn
Þingvallavatn
Þingvallavatn is a lake in south-western Iceland. With a surface of 84 km² it is the largest natural lake in Iceland. Its greatest depth is at 114 m. At the northern shore of the lake, at Þingvellir , the Alþingi, the national parliament, was founded in the year 930.The lake is part of the...

 (some 50 km to the south and easily accessible to tourists) and reappear in springs in and around the lake, while the same happens on the west side, giving rise to various tributaries of the Hvítá
Hvítá
Hvítá is a river whose source is in the glacier lake Hvítárvatn at Langjökull glacier in the highlands of Iceland at . The river flows for 40 km before dropping down into a narrow gorge at the waterfall Gullfoss....

 river as well as some rivers flowing north towards Húnaflói
Húnaflói
Húnaflói is a large bay between Strandir and Skagaströnd in Iceland. It is about wide and long. The towns Blönduós and Skagaströnd are located on the bay's eastern side....

. Thus many of the hot springs in the Borgarfjörður
Borgarfjörður
Borgarfjörður is a fjord in the west of Iceland near the town of Borgarnes. The waters of Borgarfjörður appear to be calm, however the fjord is on the contrary a rather dangerous part of the sea because of its undercurrents and shallows....

 region (near the estuary of the Hvítá on the west coast), such as Deildartunguhver
Deildartunguhver
Deildartunguhver is a hotspring in Reykholtsdalur, Iceland. It is characterized by a very high flow rate for a hot spring and water emerges at 97 °C...

, receive ground water from Langjökull.

The same is true for the lake Hvítárvatn
Hvítárvatn
Hvítárvatn is a lake in the Highlands of Iceland and the source of glacial river Hvítá. It is located 45 km northeast of Gullfoss. Its surface is about 30 km²; its greatest depth is 84 m....

 to the east: ⅔ of its waters appear to come from Langjökull by underwater channels
.

Langjökull is shrinking quite fast, and some researchers believe that it will disappear in about 150 years if climate change continues at its recent pace.

Volcanism

Under Langjökull there are 2 or more volcanic systems. The calderas can easily be seen from the air. The best known of these is Hveravellir with its hot spring and high temperature area to the east of the glacier. During an Ice Age some shield volcano
Shield volcano
A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from more explosive volcanoes...

es of this system covered the plains with lava in the region of today’s Kjölur
Kjölur
The Kjölur is a highland road in Iceland. It is the second longest of the roads through the Highlands of Iceland. It takes about 5 hours to traverse by car.- Geography :...

 mountain road: the Kjalhraun (hraun means "lava field"). The lava field is about 7800 years old.

A smaller volcanic system lies to the north-west of the glacier in the Arnarvatnsheiði, north of the glacier Eiríksjökull
Eiríksjökull
Eiríksjökull is a glacier north-west of Langjökull in Iceland, with an area of reaching a height of , making it the largest table mountain in Iceland. Rising over above its surrounding, the lowest of a hyaloclastite tuya formed presumably by a single subglacial volcanic activity is capped by a...

. About 1000 years ago, the craters of this system produced the lava field Hallmundarhraun which extends some 50 km westward into the valley of the Hvítá, and is traversed by underground streams which emerge at the beautiful waterfalls of Hraunfossar
Hraunfossar
Hraunfossar is a series of waterfalls formed by rivulets streaming over a distance of about 900 meters out of the Hallmundarhraun, a lava field which flowed from an eruption of one of the volcanoes lying under the glacier Langjökull. The waterfalls pour into the Hvítá river from ledges of less...

 not far from Húsafell
Húsafell
Húsafell is a sprawling farm and church estate and the former site of a rectory. It is the innermost farm in Borgarfjörður in the west county of Iceland, not far from Reykholt and Reykholtsdalur. Húsafell farm now serves as a hub of service for various types of tourists visiting and residing in...

.

Another volcanic system to the south-west of Langjökull is Presthnúkur, named after its central volcano, a Rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...

 dome
Lava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...

 with a high temperature area at its foot. Its fissures extend under Langjökull.

Volcanically, the region is relatively quiet, compared to other regions in Iceland, with just 32 eruptions in the last 10,000 years.

Highland roads

Two highland tracks, open in the summer months, lead alongside this glacier: the Kaldidalur
Kaldidalur
The Kaldidalsvegur is the shortest of the highland tracks traversing the Highlands of Iceland, therefore the nickname "highlands for beginners". Its name derives from the valley it crosses: kaldidalur means "cold dale/valley"...

 and Kjölur
Kjölur
The Kjölur is a highland road in Iceland. It is the second longest of the roads through the Highlands of Iceland. It takes about 5 hours to traverse by car.- Geography :...

 tracks.

The former (road F550) runs along the west of Langjökull, between it and the small Ok
Ok (glacier)
Ok is a shield volcano in Iceland, to the west of Langjökull. It erupted during interglacials in the Pleistocene. The glacier on top is thought to have disappeared ....

 glacier. To the south it leads towards Þingvellir
Þingvellir
|Thing]] Fields) is a place in Bláskógabyggð in southwestern Iceland, near the peninsula of Reykjanes and the Hengill volcanic area. Þingvellir is a site of historical, cultural, and geological importance and is one of the most popular tourist destinations in Iceland. It is the site of a rift...

 and Reykjavík, while to the north it leads to the Hvítá valley which leads down towards Borgarnes.

The latter (road F35) runs along the east side of Langjökull, between it and Hofsjökull
Hofsjökull
Hofsjökull is the third largest glacier in Iceland after Vatnajökull and Langjökull and the largest active volcano in the country. It situates at the west of the Highlands of Iceland and north of the mountain range Kerlingarfjöll, between the two largest glaciers of Iceland. It covers an area of...

. It is the main route across the interior between the main population centres in the SW and the N of the country, but nevertheless traffic is extremely sparse.

Film

In popular culture, the glacier may be best known as the place where the pieces of the nuclear-blasted Iron Giant fall in the 1999
1999 in film
The year 1999 in film involved several noteworthy events and has been called "The Year That Changed Movies". Several significant feature films, including Stanley Kubrick's final film Eyes Wide Shut, Pedro Almodóvar's first Oscar-winning film All About My Mother, science fiction The Matrix, Deep...

 animated science fiction film
Science fiction film
Science fiction film is a film genre that uses science fiction: speculative, science-based depictions of phenomena that are not necessarily accepted by mainstream science, such as extraterrestrial life forms, alien worlds, extrasensory perception, and time travel, often along with futuristic...

, The Iron Giant
The Iron Giant
The Iron Giant is a 1999 animated film produced by Warner Bros. Animation, based on the 1968 novel The Iron Man by Ted Hughes. Brad Bird directed the film, which stars a voice cast of Jennifer Aniston, Harry Connick, Jr., Vin Diesel, Eli Marienthal, Christopher McDonald and John Mahoney...

,
before it reassembles itself in the final scene of the movie.

See also

  • Geography of Iceland
    Geography of Iceland
    Iceland is a medium-sized island in the North Atlantic ocean. The island is located east of Greenland and immediately south of the Arctic Circle, atop the divergent boundary of the Mid-Atlantic Ridge in the North Atlantic Ocean. It lies about from New York City and from Scotland...

  • Glaciers of Iceland
    Glaciers of Iceland
    The glaciers and ice caps of Iceland cover 11.1% of the land area of the country and have a considerable impact on its landscape and meteorology...

  • Iceland plume
    Iceland plume
    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 ca. 2880 km depth. Opinions differ as to whether seismic studies have imaged...

  • Lakes of Iceland
  • List of islands off Iceland
  • List of volcanoes in Iceland
  • Rivers of Iceland
  • Volcanism in Iceland
  • Waterfalls of Iceland
    Waterfalls of Iceland
    Iceland is unusually suited for waterfalls. This small island country has a north Atlantic climate that produces frequent rain or snow and a near-Arctic location that produces large glaciers, whose summer melts feed many rivers...

  • List of glaciers

The glacier


Volcanism under its surface


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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