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Glaciovolcanism
Glaciovolcanism is volcanism and related phenomena associated with glacial ice. The ice commonly constrains the erupted material and melts to create meltwater. Considerable melting of glacial ice can create massive lahars and glacial outburst floods known as jökulhlaups. General Three forms of glaciovolcanism are known. Subglacial eruptions occur when a volcano erupts under ice. Such activity can produce landforms such as tuyas and subglacial mounds. Ice-marginal volcanism takes place when material from a subaerial eruption makes lateral contact with ice. Ice-marginal lava flows are a product of this phenomenon. Supraglacial eruptions deposit ejecta onto the surface of an ice sheet. World regions identified for possible glaciovolcanic activity include Alaska, and western parts of Canada, southern Chile, Argentina, Iceland, and a couple of regions along Antarctica's coast, such as the Antarctic Peninsula and the Ross Ice Shelf. Volcanologist Bill McGuire noted in 2014, Examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice-marginal Lava Flow
An ice-marginal lava flow is a lava flow that comes into direct contact with a glacier or the margins of a large ice sheet. As the lava reaches the margins of an ice sheet, the front of the lava flow cools very quickly to form a barrier. Behind this barrier, the lava begins to pool, ceasing the contact between the hot lava and cold ice. The barrier is left behind as the ice retreats, leaving a thick lava front, which is in the form of a large, steep and unstable cliff face. Examples The Barrier The Barrier in British Columbia, Canada is a natural lava dam that formed when Mount Price produced a lava flow that travelled down the Rubble Creek valley and met the Cordilleran Ice Sheet about 13,000 years ago. Two lakes behind the lava dam, Garibaldi Lake and Lesser Garibaldi Lake, formed after meltwater pooled behind the lava flow wall. The vertical slabs of lava that make up The Barrier occasionally collapse to form massive rock avalanches that travel down the valley toward local res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciovolcanism
Glaciovolcanism is volcanism and related phenomena associated with glacial ice. The ice commonly constrains the erupted material and melts to create meltwater. Considerable melting of glacial ice can create massive lahars and glacial outburst floods known as jökulhlaups. General Three forms of glaciovolcanism are known. Subglacial eruptions occur when a volcano erupts under ice. Such activity can produce landforms such as tuyas and subglacial mounds. Ice-marginal volcanism takes place when material from a subaerial eruption makes lateral contact with ice. Ice-marginal lava flows are a product of this phenomenon. Supraglacial eruptions deposit ejecta onto the surface of an ice sheet. World regions identified for possible glaciovolcanic activity include Alaska, and western parts of Canada, southern Chile, Argentina, Iceland, and a couple of regions along Antarctica's coast, such as the Antarctic Peninsula and the Ross Ice Shelf. Volcanologist Bill McGuire noted in 2014, Examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine Island Glacier
Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica's ice loss. The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. It was mapped by the United States Geological Survey (USGS) from surveys and United States Navy (USN) air photos, 1960–66, and named by the Advisory Committee on Antarctic Names (US-ACAN) in association with Pine Island Bay. The area drained by Pine Island Glacier comprises about 10% of the West Antarctic Ice Sheet. Satellite measurements have shown that the Pine Island Glacier Basin has a greater net contribution of ice to the sea than any other ice drainage basin in the world and this has increased due to recent acceleration of the ice stream. An iceberg about twice the size of Washington, DC broke off from the glacier in February 2020. Pine Island Glacier's ice velocity has accelerated to over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water. A contour line of constant salinity is called an ''isohaline'', or sometimes ''isohale''. Definitions Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate which dissolve into ions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isostatic Rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ''ocean siphoning'' and ''continental levering'', the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets.Milne, G.A., and J.X. Mitrovica (2008) ''Searching for eustasy in deglacial sea-level histories.'' Quaternary Science Reviews. 27:2292–2302. Overview During the last glacial period, much of northern Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vatnajökull
Vatnajökull ( Icelandic pronunciation: , literally "Glacier of Lakes"; sometimes translated as Vatna Glacier in English) is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island ice cap of Novaya Zemlya. It is in the south-east of the island, covering approximately 8% of the country. Size With an area of 7,900 km2, Vatnajökull is the second largest ice cap in Europe by volume (about 3,000 km3) and area (after the still larger Severny Island ice cap of Novaya Zemlya, Russia, which is in the extreme northeast of Europe). On 7 June 2008, it became a part of the Vatnajökull National Park. The average thickness of the ice is , with a maximum thickness of . Iceland's highest peak, Hvannadalshnúkur (), as part of the Öræfajökull, is in the southern periphery of Vatnajökull, near Skaftafell. Volcanoes Under the ice cap, as under many of the glaciers of Iceland, there are several List of volcanoes in Ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanism Of Iceland
:''The volcano system in Iceland that started activity on August 17, 2014, and ended on February 27, 2015, is Bárðarbunga.'' :''The volcano in Iceland that erupted in May 2011 is Grímsvötn.'' Iceland experiences frequent volcanic activity, due to its location both on the Mid-Atlantic Ridge, a divergent tectonic plate boundary, and over a hot spot. Nearly thirty volcanoes are known to have erupted in the Holocene epoch; these include Eldgjá, source of the largest lava eruption in human history. Volcanic systems and volcanic zones of Iceland Holocene volcanism in Iceland is mostly to be found in the ''Neovolcanic Zone'', comprising the Reykjanes Volcanic Belt (RVB), the West Volcanic Zone (WVZ), the Mid-Iceland Belt (MIB), the East Volcanic Zone (EVZ) and the North Volcanic Zone (NVZ). Two lateral volcanic zones play a minor role: Öræfi Volcanic Belt (ÖVB) and Snæfellsnes Volcanic Belt (SVB). Outside of the main island are the Reykjanes Ridge (RR), as part of the Mid-At ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bill McGuire (volcanologist)
William J. McGuire (born 1954) is a volcanologist and Emeritus Professor of Geophysical & Climate Hazards at University College London. His main interests include volcano instability and lateral collapse, the nature and impact of global geophysical events and the effect of climate change on geological hazards. Background McGuire studied at UCL and Luton College of Higher Education, now the University of Bedfordshire and has a PhD in Geology from University College London (1980). He began lecturing in Geology at the West London Institute of Higher Education in the 1980s, former home of well known TV geologist Iain Stewart. He was then appointed Reader at Cheltenham & Gloucester College of Higher Education (now the University of Gloucestershire), and made it into the university sector in the 1990s when he was appointed Professor of Geohazards and Director of the Aon Benfield UCL Hazard Research Centre at University College London. The centre is funded by the insurance industry. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ross Ice Shelf
The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between high above the water surface. Ninety percent of the floating ice, however, is below the water surface. Most of Ross Ice Shelf is in the Ross Dependency claimed by New Zealand. It floats in, and covers, a large southern portion of the Ross Sea and the entire Roosevelt Island located in the east of the Ross Sea. The ice shelf is named after Sir James Clark Ross, who discovered it on 28 January 1841. It was originally called "The Barrier", with various adjectives including "Great Ice Barrier", as it prevented sailing further south. Ross mapped the ice front eastward to 160° W. In 1947, the U.S. Board on Geographic Names applied the name "Ross Shelf Ice" to this feature and published it in the original U.S. Antarctic Gazetteer. In Januar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
