A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption. They are sometimes confused with volcanic craters. The word comes from Spanish caldera, and this from Latin CALDARIA, meaning "cooking pot." In some texts the English term cauldron is also used.
In 1815, the German geologist Leopold von Buch visited the Las Cañadas caldera of Teide on Tenerife, and the Caldera de Taburiente on La Palma, both in the Canary Islands. When he published his memoirs he introduced the term caldera into the geological vocabulary.
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Caldera formation [link]
A collapse is triggered by the emptying of the magma chamber beneath the volcano, usually as the result of a large volcanic eruption. If enough magma is ejected, the emptied chamber is unable to support the weight of the volcanic edifice above it. A roughly circular fracture, the ring fault, develops around the edge of the chamber. Ring fractures serve as feeders for fault intrusions which are also known as ring dykes. Secondary volcanic vents may form above the ring fracture. As the magma chamber empties, the center of the volcano within the ring fracture begins to collapse. The collapse may occur as the result of a single cataclysmic eruption, or it may occur in stages as the result of a series of eruptions. The total area that collapses may be hundreds or thousands of square kilometers.
Explosive calderas [link]
If the magma is rich in silica, the caldera is often filled in with ignimbrite, tuff, rhyolite, and other igneous rocks. Silica-rich magma has a high viscosity, and therefore does not flow easily like basalt. As a result, gases tend to become trapped at high pressure within the magma. When the magma approaches the surface of the Earth, the rapid off-loading of overlying material causes the trapped gases to decompress rapidly, thus triggering explosive destruction of the magma and spreading volcanic ash over wide areas. The lava of explosive calderas is called A'a. Further lava flows may be erupted.
If volcanic activity continues, the centre of the caldera may be uplifted in the form of a resurgent dome such as is seen at Cerro Galán, Lake Toba, Yellowstone, and so on, by subsequent intrusion of magma. A silicic or rhyolitic caldera may erupt hundreds or even thousands of cubic kilometers of material in a single event. Even small caldera-forming eruptions, such as Krakatoa in 1883 or Mount Pinatubo in 1991, may result in significant local destruction and a noticeable drop in temperature around the world. Large calderas may have even greater effects.
When Yellowstone Caldera last erupted some 650,000 years ago, it released about 1,000 km3 of material (as measured in dense rock equivalent (DRE)), covering a substantial part of North America in up to two metres of debris. By comparison, when Mount St. Helens erupted in 1980, it released ~1.2 km3 (DRE) of ejecta. The ecological effects of the eruption of a large caldera can be seen in the record of the Lake Toba eruption in Indonesia.
Toba [link]
About 75,000 years ago, this Indonesian volcano released about 2,800 km3 DRE of ejecta, the largest known eruption within the Quaternary Period (last 1.8 million years) and the largest known explosive eruption within the last 25 million years. In the late 1990s, anthropologist Stanley Ambrose[1] proposed that a volcanic winter induced by this eruption reduced the human population to about 2,000 - 20,000 individuals, resulting in a population bottleneck (see Toba catastrophe theory). More recently several geneticists, including Lynn Jorde and Henry Harpending have proposed that the human race was reduced to approximately five to ten thousand people.[2] Whichever figure is right, the fact remains that the human race seemingly came close to extinction about 75,000 years ago.
Eruptions forming even larger calderas are known, especially La Garita Caldera in the San Juan Mountains of Colorado, where the 5,000 km3 Fish Canyon Tuff was blasted out in a single major eruption about 27.8 million years ago.
At some points in geological time, rhyolitic calderas have appeared in distinct clusters. The remnants of such clusters may be found in places such as the San Juan Mountains of Colorado (formed during the Oligocene, Miocene, and Pliocene periods) or the Saint Francois Mountain Range of Missouri (erupted during the Proterozoic).
Non-explosive calderas [link]
Some volcanoes, such as shield volcanoes Kīlauea and Mauna Loa (respectively the most active and the largest on Earth, both on the island of Hawaii), form calderas in a different fashion. The magma feeding these volcanoes is basalt which is silica poor. As a result, the magma is much less viscous than the magma of a rhyolitic volcano, and the magma chamber is drained by large lava flows rather than by explosive events. The resulting calderas are also known as subsidence calderas, and can form more gradually than explosive calderas. For instance, the caldera atop Fernandina Island underwent a collapse in 1968, when parts of the caldera floor dropped 350 meters.[3] Kilauea Caldera has an inner crater known as Halema‘uma‘u, which has often been filled by a lava lake.
It is very frequent for a caldera to become emptied by drainage of melted lava through a breach on the caldera's rim. The Caldera de Taburiente and the Caldereta, both in the island of La Palma (Canary Islands), are calderas emptied by a river of lava some 500,000 years ago.
Extraterrestrial calderas [link]
Since the early 1960s, it has been known that volcanism has occurred on other planets and moons in the Solar System. Through the use of manned and unmanned spacecraft, volcanism has been discovered on Venus, Mars, the Moon and Io, a satellite of Jupiter. None of these worlds have plate tectonics, which contributes approximately 60% of the Earth's volcanic activity (the other 40% is attributed to hot spot volcanism).[4] Caldera structure is similar on all of these planetary bodies, though the size varies considerably. The average caldera diameter on Venus is 68 km. The average caldera diameter of Io is close to 40 km, and the mode is 6 km. Tvashtar Paterae is likely the largest caldera on Io with a diameter of 290 km. The average caldera diameter of Mars is 48 km, smaller than Venus. Calderas on Earth are the smallest of all planetary bodies and vary from 1.6 to 80 km as a maximum (Gottsmann 2008).
The Moon [link]
The Moon has an outer shell of low density crystalline rock that is a few hundred kilometers thick, which formed due to a rapid creation. The craters of the moon have been well preserved through time and were once thought to have been the result of extreme volcanic activity, but instead were formed by meteorites, nearly all of which took place in the first few hundred million years after the Moon formed. Around 500 million years afterward, the Moon's mantle was able to be extensively melted due to the decay of radioactive elements. Massive basaltic eruptions took place generally at the base of large impact craters. Also, eruptions may have taken place due to a magma reservoir at the base of the crust. This forms a dome, possibly the same morphology of a shield volcano where calderas universally are known to form.[4]
Mars [link]
The volcanic activity of Mars is concentrated in two major provinces, Tharsis and Elysium. Each province contains a series of giant shield volcanoes that are similar to what we see on Earth and likely are the result of mantle hot spots. The surfaces are dominated by lava flows, and all have one or more collapse calderas.[4] Mars has the largest volcano in the Solar System called Olympus Mons, which is more than three times the height of Mount Everest, with a diameter of 520 km (323 miles). The summit of the mountain has six nested calderas.[5]
Venus [link]
Because there are no plate tectonics on Venus, heat is only lost by conduction through the lithosphere. This causes enormous lava flows, accounting for 80% of Venus' surface area. Many of the mountains are large shield volcanoes that range in size from 150–400 km in diameter and 2–4 km high. More than 80 of these large shield volcanoes have summit calderas averaging 60 km across.[4]
Io [link]
Io, unusually, is heated by solid flexing due to the tidal influence of Jupiter and Io's orbital resonance with neighboring large moons Europa and Ganymede, which keeps its orbit slightly eccentric. Unlike any of the planets mentioned, Io is continuously volcanically active and contains many calderas with diameters tens of kilometers across. For example in 1979 The Voyager 1 and The Voyager 2 spotted 9 erupting volcanoes while passing Io.[4]
Mineralization [link]
Some calderas are known to host rich ore deposits. One of the world's best preserved mineralized calderas is the Neoarchean Sturgeon Lake Caldera in northeastern Ontario, Canada.[6]
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List of volcanic calderas [link]
See also Category:Volcanic calderas
- Africa
- Ngorongoro Crater (Tanzania, Africa)
- Menengai Crater (Kenya, Africa)
- Mount Elgon (Uganda/Kenya)
- Mount Fogo, Cape Verde
- Erta Ale, Ethiopia
- See Europe for calderas in the Canary Islands
- Asia
Mt.Aso's caldera measures 25 km north-south and 18 km east-west
Mt.Pinatubo, Philippines- East Asia
- Dakantou Candera (大墈头), Shanhuyan Village, Taozhu Town, Linhai, Zhejiang, China
- Ma'anshan Candera (马鞍山), Shishan Town (石山镇), Xiuying, Hainan, China
- Yiyang Candera (宜洋), Yiyang, Pingnan County, Fujian (屏南县双溪镇宜洋村), China
- Aira Caldera (Kagoshima Prefecture, Japan)
- Kussharo(Hokkaido, Japan)
- Kuttara(Hokkaido, Japan)
- Mashū(Hokkaido, Japan)
- Aso (Kumamoto Prefecture, Japan)
- Kikai Caldera (Kagoshima Prefecture, Japan)
- Towada (Aomori Prefecture, Japan)
- Tazawa (Akita Prefecture, Japan)
- Ashi (Kanagawa Prefecture, Japan)
- Mount Halla (Jeju-do, South Korea)
- Southeast Asia
- Russia
- East Asia
- Americas
- USA
Crater Lake, Oregon, formed around 5,680 BC
Aniakchak-caldera, Alaska
- Mount Aniakchak (Aniakchak National Monument and Preserve), (Alaska, US)
- Crater Lake on Mount Mazama (Crater Lake National Park, Oregon, US)
- Mount Katmai (Alaska, US)
- La Garita Caldera (Colorado, US)
- Long Valley (California, US)
- Henry's Fork Caldera (Idaho, US)
- Island Park Caldera (Idaho, Wyoming, US)
- Newberry Volcano (Oregon, US)
- Mount Okmok (Alaska, US)
- Valles Caldera (New Mexico, US)
- Yellowstone Caldera (Wyoming, US)
- Canada
- Silverthrone Caldera (British Columbia, Canada)
- Mount Edziza (British Columbia, Canada)
- Bennett Lake Volcanic Complex (British Columbia/Yukon, Canada)
- Mount Pleasant Caldera (New Brunswick, Canada)
- Sturgeon Lake Caldera (Ontario, Canada)
- Mount Skukum Volcanic Complex (Yukon, Canada)
- Blake River Megacaldera Complex (Quebec/Ontario, Canada)
- Chile
- Ecuador
- El Salvador
- Other
- USA
- Europe
- Banská Štiavnica (Slovakia)
- Bakuriani/Didveli Caldera (Georgia)
- Samsari (Georgia)
- Santorini (Greece)
- Nisyros (Greece)
- Askja (Iceland)
- Grímsvötn (Iceland)
- Katla (Iceland)
- Krafla (Iceland)
- Campi Flegrei (Italy)
- Lake Bracciano (Italy)
- Lake Bolsena (Italy)
- Las Cañadas on Teide (Spain)
- Ardnamurchan (Scotland)
- Laacher see (Germany)
- Lagoa das sete cidades on Azores islands (Portugal)
- Oceania
Satellite photo of Lake Taupo- Lake Rotorua (New Zealand)
- Lake Taupo (New Zealand)
- Maroa (New Zealand)
- Okataina (New Zealand)
- Reparoa (New Zealand)
- Kilauea (Hawaii, US)
- Moku‘āweoweo Caldera on Mauna Loa (Hawaii, US)
- Rano Kau (Easter Island, Chile)
- Tweed Volcano (New South Wales, Queensland), (Australia)
- Antarctica
- Indian Ocean
- Mars
- Olympus Mons Caldera
- Venus
- Maat Mons Caldera
Eroded calderas [link]
- Americas
- Europe
- Oceania
See also [link]
References [link]
- ^ Stanley Ambrose page at University of Illinois at Urbana-Champaign
- ^ Supervolcanoes, BBC2, 3 February 2000
- ^ "Fernandina: Photo". Global Volcanism Program, Smithsonian Institution. https://www.volcano.si.edu/world/volcano.cfm?vnum=1503-01=&volpage=photos&photo=062078.
- ^ a b c d e Parfitt, L.; Wilson, L. (Feb. 19 2008), "Volcanism on Other Planets", Fundamentals of Physical Volcanology, Malden, MA: Blackwell Publishing, pp. 190–212, ISBN 978-0-632-05443-5, OCLC 173243845, https://google.com/books?id=ptpCiNkwLj8C&printsec=frontcover
- ^ Book Title Philip's World reference Atlas Including Stars and Planets ISBN 0-7537-0310-6 Publishing House Octopus publishing Group Ltd Page 9
- ^ UMD: Precambrian Research Center
- Clough, C. T; Maufe, H. B. & Bailey, E. B; 1909. "The cauldron subsidence of Glen Coe, and the Associated Igneous Phenomena". Quarterly Journal of the Geological. Society. 65, 611-678.
- Gudmundsson, A (2008). Magma-Chamber Geometry, Fluid Transport, Local Stresses, and Rock Behavior During Collapse Caldera Formation. In Gottsmann J. & Marti, J (Ed. 10) Caldera Volcanism: Analysis, Modeling, and Response (314-346) Elsener, Amsterdam, The Netherlands
- Kokelaar, B. P; and Moore, I. D; 2006. Glencoe caldera volcano, Scotland. ISBN. 0852725252. Pub. British Geological Survey, Keyworth, Nottinghamshire. There is an associated 1:25000 solid geology map.
- Lipman, P; 1999. "Caldera". In Haraldur Sigurdsson, ed. Encyclopedia of Volcanoes. Academic Press. ISBN 0-12-643140-X
- Williams, H; 1941. Calderas and their origin. California University Publ. Geol. Sci. 25, 239-346.
External links [link]
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Caldera OpenLinux
Caldera OpenLinux (COL) is a defunct Linux distribution that was originally introduced by Caldera in 1997 based on the German LST Power Linux distribution, and then taken over and further developed by Caldera Systems (now SCO Group) since 1998. A successor to the Caldera Network Desktop put together by Caldera since 1995, OpenLinux was an early "business-oriented distribution" and foreshadowed the direction of developments that came to most other distributions and the Linux community generally.
Novell Corsair
Corsair, a user interface for NetWare, was a project run by Novell corporation's Advanced Technology Group (ATG) between 1993 and 1995. Novell wanted an internet desktop and conducted research on how to better and more easily integrate and manage network access for users. Windows's own support for connecting to Novell networks would not be improved until later releases and the Internet was dominated by Unix-based operating systems. Relative to their needs, Novell deemed the Unixes of the day were too hardware intensive, too large, and charged too much in license fees.
Caldera (film)
Caldera is an 11-minute computer animated short film released in 2012. It was directed by Evan Viera, co-written by Chris Bishop, co-produced by Chris Perry, and created in conjunction with Bit Films, the computer animation incubator program at Hampshire College in Amherst, Massachusetts.
Caldera received a Prix Ars Electronica Award of Distinction in the Computer Animation category in 2012.
Plot
Caldera is about a young girl who goes off her medication and leaves a bleak metropolis to immerse herself in a vibrant oceanic cove. Ultimately, the story is about the young girl’s impossible predicament, where she can not live in either the fantastical and haunting world of psychosis or in the marginalizing society that mandates her medication.
Awards
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External links
Éric
Éric ['eʁik] is a French masculine given name, the equivalent of English Eric. In French-speaking Canada and Belgium it is also sometimes unaccented, and pronounced "Eric" as English with the stress on the "i". A notable French exception is Erik Satie, born Éric, but who in later life signed his name "Erik" pronounced as in English.
As with Étienne, Émile, Édouard, Élisabeth, Édith the accent É is sometimes omitted in older printed sources, though French orthography is to include accents on capitals.
People named Éric
Richard Taylor (cartoonist)
Richard Taylor (1902–1970) was a Canadian cartoonist best known for his cartoons in the magazine The New Yorker. He signed his work Ric. Canadian comics historian John Bell called Taylor "one of the greatest New Yorker cartoonists".
Taylor was born in 1902 in Fort William, Ontario, in Canada. In the 1920s, he contributed to Toronto-based publications; he constirbuted for a year to Toronto Telegram newspaper, from 1927 to the University of Toronto's humour magazine The Goblin, and the Communist Party of Canada newspaper The Worker. Aside from cartooning, he produced commercial art and in his spare time painted. In 1935, The New Yorker began publishing his work, and he thereafter moved to the United States, where there were more opportunites for better pay for cartoonists. Taylor died in Bethel, Connecticut, in the United States in 1970.
References
Works cited
Further reading
RIC
Ric may refer to:
