Eruption at Krafla, 1984

The Iceland hotspot is a hotspot which is partly responsible for the high volcanic activity which has formed the island of Iceland. Krafla is a volcanic system with a diameter of about 20 km in the north of Iceland in the Mývatn region. ... 1984 is a leap year starting on Sunday of the Gregorian calendar. ... In geology, a hotspot is a location on the Earths surface that has experienced active vulcanism for a long period of time. ... Iceland (disambiguation). ...

Evidence

Iceland is one of the most active volcanic regions in the world, with eruptions occurring on average roughly every five years. About a third of the basaltic lavas erupted in recorded history have been produced by Icelandic eruptions. Notable eruptions have included that of Laki in 1783, which was the largest basaltic eruption ever witnessed, and several eruptions beneath ice caps, which have generated devastating glacial bursts, most recently in 1996. This article is about volcanoes in geology. ... Basalt Basalt is an extrusive igneous rock, sometimes porphyritic, and is often both fine-grained and dense. ... Lava is molten rock that a volcano expels during an eruption. ... The name Laki has more than one meaning:- A town called Laki in Plovdiv district in Bulgaria. ... Events February 3 - Spain recognizes United States independence. ... An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (12 million acres). ... 1996 is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ...

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. It is believed that a hotspot must lie beneath the island, enhancing the volcanism already caused by plate separation. Courtesy USGS The Mid-Atlantic Ridge is an underwater mountain range of the Atlantic Ocean that runs from Iceland to Antarctica, and is the longest mountain range on Earth. ... Categories: Plate tectonics | Geology stubs ... The North American Plate is a continental tectonic plate covering the continent of North America and extending eastward to the Mid-Atlantic Ridge. ... A seamount is a mountain rising from the seafloor that does not reach to the surface of the ocean. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... In geology, a hotspot is a location on the Earths surface that has experienced active vulcanism for a long period of time. ...

As well as driving volcanism in the centre of the island, the hotspot is also believed to feed magma to the Reykjanes ridge, another region of elevated volcanism to the southwest of the main volcanic zone of Iceland. The peninsula Reykjanes (also known under the name Reykjaneskagi) is situated at the south-west end of Iceland not far from the capital Reykjavík. ...

Nature of the hotspot

Iceland's hotspot is believed to be quite narrow, perhaps 100 km across, and extends down to between 400 and 650 km beneath the Earth's surface. As well as being a region of higher temperature than the surrounding mantle, it is also believed to have a higher concentration of water. The presence of water in magma reduces the melting temperature, and so the wetness of the Iceland hotspot probably also plays a role in enhancing Icelandic volcanism. A Mantle is a piece of clothing, similar to a robe but open on the front side and often sleeveless. ... Drinking water This article focuses on water as we experience it every day. ... This article is about the type of rock. ...

Some geologists have questioned whether the Iceland hotspot has the same origin as other hotspots such as the Hawaii hotspot. While the Hawaiian island chain and Emperor Seamounts show a clear time-progressive volcanic track caused by the movement of the Pacific Plate over the Hawaiian hotspot, no such track exists at Iceland. Studies also suggest that the hotspot is only 50-100 K hotter than its surroundings, which may not be a great enough difference to drive a buoyant plume. Rather than being driven by a deep mantle plume, the Iceland hotspot may originate at a much shallower depth. The Emperor Seamounts are a chain of seamounts (submerged volcanic mountains) extending from the northwestern Hawaiian Islands (see Kure and Midway atolls) in a northwesterly direction until approximately 170º east longitude where they trend abruptly northward towards the tip of the Aleutian Islands and the Kamchatka Peninsula. ... The Pacific Plate is an oceanic tectonic plate beneath the Pacific Ocean. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... In physics, buoyancy is an upward force on an object immersed in a fluid (i. ...

References

1. Allen R.M., Nolet G., Morgan W.J. et al (1999), The thin hot plume beneath Iceland, Geophysical Journal International, v. 137, pp. 51-63
2. Foulger G.R., Anderson D.L. (2005), A cool model for the Iceland hotspot, Journal of Volcanology and Geothermal Research, v. 141, p. 1–22
3. 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, v. 202, p. 77-87

External links

• http://www.mantleplumes.org/Iceland3.html