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For other uses, see Caldera (disambiguation).
Satellite image of Santorini. The Minoan caldera is at the lower part of the image and formed in the Minoan eruption approx. 3615 BP. The whole caldera is formed of three overlapping calderas. Clockwise from centre: Nea Kameni; Palea Kameni; Aspronisi; Therasia; Thera
Satellite image of Santorini. The Minoan caldera is at the lower part of the image and formed in the Minoan eruption approx. The Minoan eruption of Thera, also referred to as the Thera eruption or Santorini eruption was a major catastrophic volcanic eruption ( VEI 3615 BP. Before Present (BP years are a time scale used in Archaeology, Geology, and other scientific disciplines to specify when events in the past occurred The whole caldera is formed of three overlapping calderas. Clockwise from centre: Nea Kameni; Palea Kameni; Aspronisi; Therasia; Thera

A caldera is a volcanic feature formed by the collapse of land following a volcanic eruption. Plate tectonics and hotspots Divergent plate boundaries At the They are sometimes confused with volcanic craters. A volcanic crater is a circular depression in the ground caused by volcanic activity The word comes from Spanish, meaning "bowl". In some texts the English term cauldron is also used.

In 1815, the German geologist Leopold von Buch visited the Las Cañadas Caldera Teide, Tenerife and the Caldera de Taburiente, La Palma, both in the Canary Islands. Christian Leopold Freiherr von Buch ( April 26, 1774 - March 4, 1853) was a German Geologist and Paleontologist Mount Teide or in Spanish El Teide, is an active though dormant Volcano which last erupted in 1909 from the El Chinyero vent on the Santiago (northwestern rift Tenerife (previously known and spelled as "Teneriffe" in English before mass tourism adopted the Spanish spelling a Spanish Island, is the largest Parque Nacional de la Caldera de Taburiente is a national park on the island of La Palma, Canary Islands, Spain, located at. Isla de La Palma (known in English as "La Palma" not to be confused with "Palma" in the Balearic Islands is a Spanish volcanic ocean island The Canary Islands ( English pronunciation kəˈnæriː ˈaɪləndz Spanish: Islas Canarias, ˈizlas kaˈnarjas are a Spanish When he published his memoirs he introduced the term "caldera" into the geological vocabulary.

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Caldera formation

A collapse is triggered by the emptying of the magma chamber beneath the volcano, usually as the result of a large volcanic eruption. A magma chamber is a large underground pool of molten rock lying under the surface of the earth's crust Plate tectonics and hotspots Divergent plate boundaries At the If enough magma is erupted, the emptied chamber will not be able to support the weight of the volcanic edifice above it. A roughly circular fracture - the "Ring Fault" develops around the edge of the chamber. These 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 centre 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 km2.

Landsat image of Lake Toba. A resurgent dome formed the island of Samosir.
Landsat image of Lake Toba. The Landsat program is the longest running enterprise for acquisition of imagery of Earth from space Lake Toba ( Danau Toba) is a Lake and Supervolcano, 100 km long and 30 km wide and 505 m A resurgent dome formed the island of Samosir. In Geology, a resurgent dome is a dome formed by swelling or rising of a Caldera floor due to movement in the Magma chamber beneath it Samosir, or Pulau Samosir, is a large volcanic island in Lake Toba.

Explosive calderas

If the magma is rich in silica, the caldera is often filled in with ignimbrite, tuff, rhyolite, and other igneous rocks. Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Ignimbrite is a Volcanic Pyroclastic rock often of Dacitic or Rhyolitic composition Tuff (from the Italian "tufo" is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption This page is about a volcanic rock For the ghost town see Rhyolite Nevada, and for the satellite system see Rhyolite/Aquacade. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Silica-rich magma does not flow like basalt due to having a high viscosity. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. As a result, gases tend to become trapped at high pressure within the magma. When the magma approaches the surface of the Earth, the gases decompress rapidly, causing explosive destruction of the magma and spreading volcanic ash over wide areas. Volcanic ash consists of small Tephra, which are bits of pulverized rock and glass created by volcanic eruptions less than in diameter Further lava flows may be erupted. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures

If volcanic activity continues the centre of the caldera may be uplifted in the form of a resurgent dome such as is seen seen at Cerro Galán, Toba, Yellowstone etc; by subsequent intrusion of magma. In Geology, a resurgent dome is a dome formed by swelling or rising of a Caldera floor due to movement in the Magma chamber beneath it Cerro Galán is a Caldera in Catamarca Province, Argentina, considered to be the best exposed large Caldera in the world A silicic or rhyolitic caldera may erupt hundreds or even thousands of cubic kilometers of material in a single event. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. 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. Krakatoa ( Indonesian: Krakatau) also spelled Krakatao or Krakatowa, is a volcanic island in the Sunda Strait Mount Pinatubo is an active Stratovolcano located on the island of Luzon Large calderas may have even greater effects.

When Yellowstone Caldera last erupted ~640 ka, it released ~1,000 km3 of dense rock equivalent (DRE) material, covering a substantial part of North America in up to two metres of debris. The Yellowstone Caldera is the volcanic Caldera in Yellowstone National Park in the United States. By comparison, when Mount St. Helens erupted in 1980, it released ~1. Mount St Helens is an active Stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States 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. Lake Toba ( Danau Toba) is a Lake and Supervolcano, 100 km long and 30 km wide and 505 m The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia.

Toba

About 75,000 years ago, this Indonesian volcano released ~2. 8 x 103 km3 DRE of ejecta, the largest known eruption within the Quaternary Period (last 1. Overview The term Quaternary ("fourth" was proposed by Giovanni Arduino in 1759 for alluvial deposits in the Po river valley in northern 8 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). Anthropology (/ˌænθɹəˈpɒlədʒi/ from Greek grc ἄνθρωπος anthrōpos, "human" -λογία -logia) is the study of A volcanic winter is the reduction in temperature caused by Volcanic ash and droplets of Sulfuric acid obscuring the Sun and lowering the Albedo Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus A population bottleneck (or genetic bottleneck) is an Evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented According to the Toba catastrophe theory, 70000 to 75000 years ago a supervolcanic event at Lake Toba, on Sumatra, reduced the world's human population More recently several geneticists, including Lynn Jorde and Henry Harpending have proposed that the human race was reduced to approximately 5,000 to 10,000 people. Henry C Harpending (1944-) is an anthropologist and population geneticist at the University of Utah, where he is a [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. La Garita Caldera is a large volcanic Caldera located in the San Juan volcanic field in the San Juan Mountains in southwestern Colorado The San Juan Mountains are a rugged Mountain range in the Rocky Mountains in southwestern Colorado. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. 0 x 103 km3 Fish Canyon Tuff was blasted out in a major single eruption ~27. 8 million years ago.

At some points in geological time, rhyolitic calderas have appeared in distinct clusters. The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other The remnants of such clusters may be found in places such as the San Juan Mountains of Colorado (erupted during the Tertiary Period) or the Saint Francois Mountain Range of Missouri (erupted during the Proterozoic). The San Juan Mountains are a rugged Mountain range in the Rocky Mountains in southwestern Colorado. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately The Saint Francois Mountains, a range located in southeast Missouri, is an outcrop of Precambrian Igneous rock mountains rising over the Ozark Missouri ( or) is a state in the Midwestern region of the United States bordered by Iowa, Illinois, Kentucky, Tennessee The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth.

Satellite photograph of Fernandina Island's summit caldera
Satellite photograph of Fernandina Island's summit caldera

Non-explosive calderas

Some volcanoes, such as Kīlauea on the island of Hawaii, form calderas in a different fashion. Fernandina Island (formerly known in English as Narborough Island is the third largest and youngest island of the Galápagos Islands. Kīlauea (kiːlauea is an active Volcano in the Hawaiian Islands, one of five Shield volcanoes that together form the Island of Hawai{{okina}}i The Island of Hawaii, also called the Big Island or Hawaii Island, is a volcanic Island in the U In the case of Kilauea, the magma feeding the volcano is basalt which is silica poor. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. 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. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. 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. Fernandina Island (formerly known in English as Narborough Island is the third largest and youngest island of the Galápagos Islands. [3] Kilauea Caldera has an inner crater known as Halema‘uma‘u, which has often been filled by a lava lake. Kīlauea (kiːlauea is an active Volcano in the Hawaiian Islands, one of five Shield volcanoes that together form the Island of Hawai{{okina}}i At the summit of largest volcano on Earth, Mauna Loa is a subsidence caldera called Moku‘āweoweo Caldera. Mauna Loa is the largest volcano on earth and one of five volcanoes that form the Island of Hawaii in the U

Non-volcanic calderas

It is possible, although rare, for a caldera-like formation to be created by erosion rather than volcanism. Some geologists consider that the Caldera de Taburiente on La Palma in the Canary Islands may be an erosion caldera. Parque Nacional de la Caldera de Taburiente is a national park on the island of La Palma, Canary Islands, Spain, located at. Isla de La Palma (known in English as "La Palma" not to be confused with "Palma" in the Balearic Islands is a Spanish volcanic ocean island The Canary Islands ( English pronunciation kəˈnæriː ˈaɪləndz Spanish: Islas Canarias, ˈizlas kaˈnarjas are a Spanish

Mineralization

Some calderas are known to support rich mineralogy. Mineralogy is an Earth Science focused around the Chemistry, Crystal structure, and physical (including optical) properties of Minerals One of the world's best preserved mineralized calderas is the Neoarchean Sturgeon Lake Caldera in northeastern Ontario, Canada. The Neoarchean (ˌniːoʊɑrˈkiːən also spelled Neoarchaean) is a geologic era within the Archaean. Sturgeon Lake Caldera is a large extinct Caldera in Kenora District of Northwestern Ontario, Canada. Cities and towns Northeastern Ontario has six cities They are Greater Sudbury, Sault Ste Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page [1]


Notable calderas

See also Category:Volcanic calderas

Crater Lake, Oregon, formed around 5,680 BC
Crater Lake, Oregon, formed around 5,680 BC
Satellite photo of Lake Taupo
Satellite photo of Lake Taupo

See also

External links

Notes

  1. ^ UMD: Precambrian Research Center

References

Dictionary

caldera

-noun

  1. (geology) A large crater formed by volcanic explosion or by collapse of the cone of a volcano
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