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63-399: The volcano consists of a 3.5-kilometre-wide (2.2 mi) caldera and two stratovolcanoes . Four pyroclastic cones located 7 kilometres (4.3 mi) to the northeast have produced basalt - andesite lava flows that cover an area of 10 square kilometres (4 sq mi). Incahuasi lies on the border between Argentina and Chile , close to Paso San Francisco . A major road crosses

126-409: A caldera, possibly an ash-flow caldera. 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. Mars has the tallest volcano in

189-416: A cylindrical vent. Unlike shield volcanoes , they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions . Some have collapsed craters called calderas . The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around 500 meters (1,600 ft) to over several kilometers in diameter. This central core

252-400: A diameter of 290 km (180 mi). The average caldera diameter on Mars is 48 km (30 mi), smaller than Venus. Calderas on Earth are the smallest of all planetary bodies and vary from 1.6–80 km (1–50 mi) as a maximum. 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

315-430: A few days to a few years. Of observed cinder cone eruptions, 50% have lasted for less than 30 days, and 95% stopped within one year. In case of Parícutin, its eruption lasted for nine years from 1943 to 1952. Rarely do they erupt either two, three, or more times. Later eruptions typically produce new cones within a volcanic field at separation distances of a few kilometers and separate by periods of 100 to 1,000 years. Within

378-467: A magma chamber whose magma is rich in silica . Silica-rich magma has a high viscosity , and therefore does not flow easily like basalt . The magma typically also contains a large amount of dissolved gases, up to 7 wt% for the most silica-rich magmas. When the magma approaches the surface of the Earth, the drop in confining pressure causes the trapped gases to rapidly bubble out of the magma, fragmenting

441-601: A major lava dome and a field of lava flows. Incahuasi rises over a surface with elevations of 4,300–4,700 metres (14,100–15,400 ft). The volcano is surrounded by a field of small volcanoes that is known as the Incahuasi field; it contains 19 small volcanoes with a total rock volume of 4.4 cubic kilometres (1.1 cu mi), which were active during the last 1 million years. Like many Andean volcanoes, Incahuasi has erupted andesite containing hornblende and pyroxene , but also trachyandesite and trachydacite . Lava flows on

504-454: A north-south stretching, which led to a change in the alignments of the volcanoes. Incahuasi is formed by a caldera 3.5 kilometres (2.2 mi) wide. Two coalesced stratovolcanoes formed within the caldera and have a diameter of 15 kilometres (9.3 mi). A 6-by-4-kilometre-wide (3.7 mi × 2.5 mi) lava dome is located on the eastern flank. The volcano has a volume of about 231 cubic kilometres (55 cu mi) and covers

567-583: A noticeable drop in temperature around the world. Large calderas may have even greater effects. The ecological effects of the eruption of a large caldera can be seen in the record of the Lake Toba eruption in Indonesia . 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 Eocene Rum Complex of Scotland,

630-1026: A single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that often is noticeably symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit. The basal diameters of cinder cones average about 800 meters (2,600 ft) and range from 250 to 2,500 meters (820 to 8,200 ft). The diameter of their craters ranges between 50 and 600 meters (160 and 1,970 ft). Cinder cones rarely rise more than 50–350 meters (160–1,150 ft) or so above their surroundings. Cinder cones most commonly occur as isolated cones in large basaltic volcanic fields. They also occur in nested clusters in association with complex tuff ring and maar complexes. Finally, they are also common as parasitic and monogenetic cones on complex shield and stratovolcanoes. Globally, cinder cones are

693-482: A surface area of about 207 square kilometres (80 sq mi). With a height of 6,621 metres (21,722 ft), Incahuasi is the 12th-highest mountain in South America and one of the world's highest volcanoes. Incahuasi has two craters , a summit crater and an arcuate crater on the eastern slope that contains a lava dome. The summit crater has dimensions of 750 by 900 metres (2,460 ft × 2,950 ft) and

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756-399: A tuff cone have commonly been altered, palagonitized , by either its interaction with groundwater or when it was deposited warm and wet. The pyroclastic deposits of tuff cones differ from the pyroclastic deposits of spatter cones by their lack or paucity of lava spatter, smaller grain-size, and excellent bedding. Typically, but not always, tuff cones lack associated lava flows. A tuff ring

819-525: A volcanic field, eruptions can occur over a period of a million years. Once eruptions cease, being unconsolidated, cinder cones tend to erode rapidly unless further eruptions occur. Rootless cones , also called pseudocraters , are volcanic cones that are not directly associated with a conduit that brought magma to the surface from a deep-seated magma reservoir. Generally, three types of rootless cones, littoral cones , explosion craters , and hornitos are recognized. Littoral cones and explosion craters are

882-410: Is a large cauldron -like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption . An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the structural integrity of such a chamber, greatly diminishing its capacity to support its own roof, and any substrate or rock resting above. The ground surface then collapses into

945-637: Is a low, steep-sided hill or mound that consists of welded lava fragments, called spatter, which has formed around a lava fountain issuing from a central vent. Typically, spatter cones are about 3–5 meters (9.8–16.4 ft) high. In case of a linear fissure, lava fountaining will create broad embankments of spatter, called spatter ramparts, along both sides of the fissure. Spatter cones are more circular and cone shaped, while spatter ramparts are linear wall-like features. Spatter cones and spatter ramparts are typically formed by lava fountaining associated with mafic , highly fluid lavas, such as those erupted in

1008-408: Is a related type of small monogenetic volcano that is also produced by phreatic (hydrovolcanic) explosions directly associated with magma brought to the surface through a conduit from a deep-seated magma reservoir. They are characterized by rims that have a low, broad topographic profiles and gentle topographic slopes that are 25 degrees or less. The maximum thickness of the pyroclastic debris comprising

1071-666: Is a small monogenetic volcanic cone produced by phreatic (hydrovolcanic) explosions directly associated with magma brought to the surface through a conduit from a deep-seated magma reservoir. They are characterized by high rims that have a maximum relief of 100–800 meters (330–2,620 ft) above the crater floor and steep slopes that are greater than 25 degrees. They typically have a rim to rim diameter of 300–5,000 meters (980–16,400 ft). A tuff cone consists typically of thick-bedded pyroclastic flow and surge deposits created by eruption-fed density currents and bomb-scoria beds derived from fallout from its eruption column. The tuffs composing

1134-640: Is dominated by volcanoes that were active after 1.5 million years ago. Also located close to Incahuasi are Falso Azufre and Nevado San Francisco , as well as the Miocene Cerro Morocho and Cerro Ojo de Las Lozas volcanoes. It has been suggested that a perpendicular chain of volcanoes including Ojos del Salado may be the consequence of the Juan Fernández Ridge subducting in the Peru–Chile Trench . Geological evidence suggests that volcanism in

1197-405: 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 dikes . Secondary volcanic vents may form above the ring fracture. As the magma chamber empties, the center of the volcano within

1260-437: Is embedded within a 2-kilometre-high (1.2 mi) summit plateau. Subsidiary vents conversely are associated with fissure vents . The edifice appears to consist of two overlapping volcanoes. The western and southwestern slopes of Incahuasi are dotted with lava domes, which are more subdued than on other volcanoes in the region. Lava flows less than 1 kilometre (0.62 mi) wide and 5 kilometres (3.1 mi) long extend down

1323-569: 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 keep its orbit slightly eccentric . Unlike any of the planets mentioned, Io is continuously volcanically active. For example, the NASA Voyager 1 and Voyager 2 spacecraft detected nine erupting volcanoes while passing Io in 1979. Io has many calderas with diameters tens of kilometers across. Pyroclastic cone Volcanic cones are among

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1386-506: Is known to occur with long rest phases between eruptions (reaching one million years). There are reports of fumarolic activity. The volcano is considered a potential geological hazard to Argentina and Chile, where the SERNAGEOMIN hazard maps identify it as a potential threat. The remoteness of the volcano means that future eruptions are unlikely to impact populated areas, however, other than International Route CH-31  [ es ] . It

1449-529: Is relatively young (1.25 million years old) and unusually well preserved, and it remains one of the best studied examples of a resurgent caldera. The ash flow tuffs of the Valles caldera, such as the Bandelier Tuff , were among the first to be thoroughly characterized. About 74,000 years ago, this Indonesian volcano released about 2,800 cubic kilometres (670 cu mi) dense-rock equivalent of ejecta. This

1512-414: Is surrounded by multiple generations of lava flows, many of which are brecciated , and a wide range of pyroclastic rocks and reworked volcanic debris. The typical stratocone is an andesitic to dacitic volcano that is associated with subduction zones . They are also known as either stratified volcano, composite cone, bedded volcano, cone of mixed type or Vesuvian-type volcano. A spatter cone

1575-500: The San Juan Mountains of Colorado , where the 5,000 cubic kilometres (1,200 cu mi) Fish Canyon Tuff was blasted out in eruptions about 27.8 million years ago. The caldera produced by such eruptions is typically filled in with tuff, rhyolite , and other igneous rocks . The caldera is surrounded by an outflow sheet of ash flow tuff (also called an ash flow sheet ). If magma continues to be injected into

1638-417: The Earth's volcanic activity (the other 40% is attributed to hotspot volcanism). Caldera structure is similar on all of these planetary bodies, though the size varies considerably. The average caldera diameter on Venus is 68 km (42 mi). The average caldera diameter on Io is close to 40 km (25 mi), and the mode is 6 km (3.7 mi); Tvashtar Paterae is likely the largest caldera with

1701-661: The English term cauldron is also used, though in more recent work the term cauldron refers to a caldera that has been deeply eroded to expose the beds under the caldera floor. The term caldera was introduced into the geological vocabulary by the German geologist Leopold von Buch when he published his memoirs of his 1815 visit to the Canary Islands , where he first saw the Las Cañadas caldera on Tenerife , with Mount Teide dominating

1764-571: The Hawaiian Islands. As blobs of molten lava, spatter, are erupted into the air by a lava fountain, they can lack the time needed to cool completely before hitting the ground. Consequently, the spatter are not fully solid, like taffy , as they land and they bind to the underlying spatter as both often slowly ooze down the side of the cone. As a result, the spatter builds up a cone that is composed of spatter either agglutinated or welded to each other. A tuff cone , sometimes called an ash cone ,

1827-510: The Moon have been well preserved through time and were once thought to have been the result of extreme volcanic activity, but are currently believed to have been 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

1890-647: The San Juan Mountains of Colorado (formed during the Oligocene , Miocene , and Pliocene epochs) or the Saint Francois Mountain Range of Missouri (erupted during the Proterozoic eon). For their 1968 paper that first introduced the concept of a resurgent caldera to geology, R.L. Smith and R.A. Bailey chose the Valles caldera as their model. Although the Valles caldera is not unusually large, it

1953-720: The Solar System, 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. Because there is no plate tectonics on Venus , heat is mainly 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 (95–250 mi) in diameter and 2–4 km (1.2–2.5 mi) high. More than 80 of these large shield volcanoes have summit calderas averaging 60 km (37 mi) across. Io, unusually,

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2016-548: The area dates back to the Oligocene and Miocene , when the main volcanic arc was located 40 kilometres (25 mi) west in the Maricunga Belt . Between 9 and 6 million years ago, volcanic activity in the Maricunga Belt decreased and eventually ceased. Simultaneously, the back-arc experienced increased volcanic activity. Beginning 8.3 million years ago, there was a change in tectonic regime from an east-west compression to

2079-411: 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. Although caldera-like structures are rare on the Moon, they are not completely absent. The Compton-Belkovich Volcanic Complex on the far side of the Moon is thought to be

2142-754: The border there. Incahuasi is part of the Central Volcanic Zone of the Andes , together with about 110 other Quaternary volcanoes, and lies in the southern sector of this zone; other volcanic zones in the Andes are the Northern Volcanic Zone , the Southern Volcanic Zone , and the Austral Volcanic Zone . The history of volcanic activity of most of these volcanoes is poorly understood owing to

2205-577: The caldera atop Fernandina Island collapsed in 1968 when parts of the caldera floor dropped 350 metres (1,150 ft). 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 crewed and uncrewed 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

2268-426: The calderas and volcanic cones of Ulysses Patera , Ulysses Colles and Hydraotes Chaos are argued to be cinder cones. Cinder cones typically only erupt once like Parícutin. As a result, they are considered to be monogenetic volcanoes and most of them form monogenetic volcanic fields . Cinder cones are typically active for very brief periods of time before becoming inactive. Their eruptions range in duration from

2331-664: The collapsed magma chamber, the center of the caldera may be uplifted in the form of a resurgent dome such as is seen at the Valles Caldera , Lake Toba , the San Juan volcanic field, Cerro Galán , Yellowstone , and many other calderas. Because a silicic caldera may erupt hundreds or even thousands of cubic kilometers of material in a single event, it can cause catastrophic environmental effects. Even small caldera-forming eruptions, such as Krakatoa in 1883 or Mount Pinatubo in 1991, may result in significant local destruction and

2394-522: The crater does not support the development of glaciers. Average precipitation at Incahuasi is about 300–500 millimetres per year (12–20 in/year). The volcano lies south of the so-called "Arid Diagonal", and most precipitation falls during winter. This aridity is caused by the rain shadow effect of the Subandean Ranges, which block moisture from the Atlantic Ocean . One andesitic lava flow on

2457-422: The crater of a tuff ring generally has been excavated below the existing ground surface. As a result, water commonly fills a tuff ring's crater to form a lake once eruptions cease. Both tuff cones and their associated tuff rings were created by explosive eruptions from a vent where the magma is interacting with either groundwater or a shallow body of water as found within a lake or sea. The interaction between

2520-403: The emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater , the feature is actually a type of sinkhole , as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur over the course of a century,

2583-414: The extension of the crust compared to the compressional regime farther west. Originating in the mantle , the magmas quickly ascended in faults and were contaminated by crustal material. The mantle itself had been modified before by crustal material added by delamination of the lower crust and subduction erosion . Incahuasi does not have glaciers , but it does have at least temporary snowpack . Even

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2646-464: The formation of a caldera is a rare event, occurring only a few times within a given window of 100 years. Only eight caldera-forming collapses are known to have occurred between 1911 and 2018, with a caldera collapse at Kīlauea , Hawaii in 2018. Volcanoes that have formed a caldera are sometimes described as "caldera volcanoes". The term caldera comes from Spanish caldera , and Latin caldaria , meaning "cooking pot". In some texts

2709-463: The human species was reduced to approximately 5,000–10,000 people. There is no direct evidence, however, that either theory is correct, and there is no evidence for any other animal decline or extinction, even in environmentally sensitive species. There is evidence that human habitation continued in India after the eruption. Some volcanoes, such as the large shield volcanoes Kīlauea and Mauna Loa on

2772-429: 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,

2835-502: The lack of dating; only a few historical eruptions have been recorded, such as an eruption at Ojos del Salado in 1993. Incahuasi is located northeast of Ojos del Salado , the highest volcano in the world. Both volcanoes are found at the southern end of the Central Volcanic Zone. Together with El Fraile , Cerro El Muerto , Nevado Tres Cruces , and El Solo , they form a 50-kilometre-long (31 mi) volcanic chain. The area

2898-479: The landscape, and then the Caldera de Taburiente on La Palma . A collapse is triggered by the emptying of the magma chamber beneath the volcano, sometimes as the result of a large explosive volcanic eruption (see Tambora in 1815), but also during effusive eruptions on the flanks of a volcano (see Piton de la Fournaise in 2007) or in a connected fissure system (see Bárðarbunga in 2014–2015). If enough magma

2961-558: The lava dome and lava flow fields (760,000 ± 90,000 and 740,000 ± 50,000 years ago, respectively) and a lava flow from the pyroclastic cones, which has been dated to 350,000 ± 30,000 years ago. Volcanic activity at Incahuasi may have continued into the Holocene , considering the young appearance of its eruption products such as lava flows in the summit region and on the southern slopes; the old ages obtained by radiometric dating indicate an extinct volcano , although activity at Andean volcanoes

3024-561: The magma to produce a mixture of volcanic ash and other tephra with the very hot gases. The mixture of ash and volcanic gases initially rises into the atmosphere as an eruption column . However, as the volume of erupted material increases, the eruption column is unable to entrain enough air to remain buoyant, and the eruption column collapses into a tephra fountain that falls back to the surface to form pyroclastic flows . Eruptions of this type can spread ash over vast areas, so that ash flow tuffs emplaced by silicic caldera eruptions are

3087-638: The magma, expanding steam, and volcanic gases resulted in the production and ejection of fine-grained pyroclastic debris called ash with the consistency of flour . The volcanic ash comprising a tuff cone accumulated either as fallout from eruption columns, from low-density volcanic surges and pyroclastic flows, or combination of these. Tuff cones are typically associated with volcanic eruptions within shallow bodies of water and tuff rings are associated with eruptions within either water saturated sediments and bedrock or permafrost . Next to spatter (scoria) cones, tuff cones and their associated tuff rings are among

3150-414: The main stratovolcano are dacitic . The four cones northeast of the principal volcano have erupted basaltic andesite . Likewise, parasitic cones have erupted magnesium-rich basaltic andesite. Minerals contained in these rocks include clinopyroxene and olivine . The occurrence of such basic magmas in a volcanic setting dominated by dacites appears to be a consequence of local tectonics, which involve

3213-748: The most common types of volcanoes on Earth. An example of a tuff cone is Diamond Head at Waikīkī in Hawaiʻi . Clusters of pitted cones observed in the Nephentes/Amenthes region of Mars at the southern margin of the ancient Utopia impact basin are currently interpreted as being tuff cones and rings. Cinder cones , also known as scoria cones and less commonly scoria mounds , are small, steep-sided volcanic cones built of loose pyroclastic fragments, such as either volcanic clinkers, cinders, volcanic ash, or scoria . They consist of loose pyroclastic debris formed by explosive eruptions or lava fountains from

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3276-687: The most typical volcanic landform found within continental intraplate volcanic fields and also occur in some subduction zone settings as well. Parícutin , the Mexican cinder cone which was born in a cornfield on February 20, 1943, and Sunset Crater in Northern Arizona in the US Southwest are classic examples of cinder cones, as are ancient volcanic cones found in New Mexico's Petroglyph National Monument . Cone-shaped hills observed in satellite imagery of

3339-437: The northwestern slope of Incahuasi has yielded two ages, one of 1.15 ± 0.5 million years ago and another of 710,000 ± 80,000 years ago. Based on their preservations, the lava flows appear to be of roughly comparable ages. Additional ages were obtained on the main edifice, 1.57 ± 0.1 million years ago, 1.14 ± 0.37 million years ago, and 1.00 ± 0.13 million years ago. Parasitic cones were active over 500,000 years ago. These include

3402-468: The only volcanic product with volumes rivaling those of flood basalts . For example, when Yellowstone Caldera last erupted some 650,000 years ago, it released about 1,000 km of material (as measured in dense rock equivalent (DRE)), covering a substantial part of North America in up to two metres of debris. Eruptions forming even larger calderas are known, such as the La Garita Caldera in

3465-1013: The region appear to have had functions correlated to that of the Incahuasi site. 1: Aconcagua (6.962 m) - Mendoza 2: Ojos del Salado (6.893 m) - Catamarca 3: Monte Pissis (6.793 m) - La Rioja 4: Cerro Bonete (6.759 m) - La Rioja 5: Tres Cruces (6.748 m) - Catamarca 6: Llullaillaco (6.739 m) - Salta 7: Mercedario (6.710 m) - San Juan 8: Tipas (6.670 m) - Catamarca 9: Incahuasi (6.621 m) - Catamarca 10: Tupungato (6.570 m) - Mendoza 11: El Muerto (6.510 m) - Catamarca 12: Nacimiento (6.460 m) - Catamarca 13: Veladero (6.436 m) - La Rioja 14: El Cóndor (6.414 m) - Catamarca 15: Antofalla (6.409 m) - Catamarca 16: Ramada (6.384 m) - San Juan 17: Cachi (6.380 m) - Salta 18: Reclus (6.335 m) - La Rioja 19: La Majadita (6.280 m) - San Juan 20: Los Patos (6.239 m) - Catamarca Caldera A caldera ( / k ɔː l ˈ d ɛr ə , k æ l -/ kawl- DERR -ə, kal- )

3528-494: The result of mild explosions that were generated locally by the interaction of either hot lava or pyroclastic flows with water. Littoral cones typically form on the surface of a basaltic lava flow where it has entered into a body of water, usually a sea or ocean. Explosion craters form where either hot lava or pyroclastic flows have covered either marshy ground or water-saturated ground of some sort. Hornitos are rootless cones that are composed of welded lava fragments and were formed on

3591-421: The rim of a typical tuff ring is generally thin, less than 50 meters (160 ft) to 100 meters (330 ft) thick. The pyroclastic materials that comprise their rim consist primarily of relatively fresh and unaltered, distinctly and thin-bedded volcanic surge and air fall deposits. Their rims also can contain variable amounts of local country rock (bedrock) blasted out of their crater. In contrast to tuff cones,

3654-462: 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 of square kilometers. Some calderas are known to host rich ore deposits . Metal-rich fluids can circulate through the caldera, forming hydrothermal ore deposits of metals such as lead, silver, gold, mercury, lithium, and uranium. One of

3717-553: The simplest volcanic landforms . They are built by ejecta from a volcanic vent , piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones , spatter cones , tuff cones , and cinder cones . Stratocones are large cone-shaped volcanoes made up of lava flows , explosively erupted pyroclastic rocks, and igneous intrusives that are typically centered around

3780-503: The volcano. They reach the Las Coladas salar east of Incahuasi. Two 2-kilometre-long (1.2 mi) coulees extend north and east of the main crater. 7 kilometres (4.3 mi) northeast of Incahuasi, four pyroclastic cones can be found. They have covered 10 square kilometres (3.9 sq mi) with lava but they are probably an independent volcanic system, similar to other regional mafic volcanoes. On Incahuasi's eastern flank lies

3843-633: The world's best-preserved mineralized calderas is the Sturgeon Lake Caldera in northwestern Ontario , Canada, which formed during the Neoarchean era about 2.7 billion years ago. In the San Juan volcanic field , ore veins were emplaced in fractures associated with several calderas, with the greatest mineralization taking place near the youngest and most silicic intrusions associated with each caldera. Explosive caldera eruptions are produced by

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3906-443: Was rated 27th out of 38 Argentine-Chilean volcanoes in dangerousness. The mountain was first climbed by Inca people. In 1912, Walter Penck climbed the mountain. Legend has it that a railway engineer named Edward Flint ascended the mountain between 1854 and 1859. In 1913, an Inca ceremonial structure was found on the summit of Incahuasi. Another archaeological site, "Fiambalá-1", lies at its foot. Other Inca archaeological sites in

3969-464: Was the largest known eruption during the ongoing Quaternary period (the last 2.6 million years) and the largest known explosive eruption during the last 25 million years. In the late 1990s, anthropologist Stanley Ambrose 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 . More recently, Lynn Jorde and Henry Harpending proposed that

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