Falso Azufre is a

complex volcano A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. They may form due to changes in eruptive habit or ...

at the border of

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. Falso Azufre is elongated in east–west direction and contains craters and

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

s; most craters have diameters of with the exception of the main crater, which is wide.Grosse, et al. 2018, p. 12 The highest summit Cerro Falso Azufre lies at the western end in Chile, which has mostly generated pyroclastic material from craters. The probably youngest segment of the volcano is the eastern section in Argentina, where two lava domes and two cones are located; these form the Dos Conos volcano. Some lava flows linked to Dos Conos are up to long.Grosse, et al. 2018, p. 13 The oldest is known as the Kunstmann edifice on the northwestern side of Falso Azufre; Kunstmann volcano features a wide scar formed by a

sector collapse A sector collapse or lateral collapse is the structural failure and subsequent collapse of a minimum volume of of a volcano. Unlike smaller flank collapses, a sector collapse can involve the central volcanic pipe and historically this term had b ...

. Falso Azufre with a base surface of is one of the biggest volcanoes in the area. The presence of two oppositely curved vent alignments gives the complex an arc-like shape which reaches heights of about above sea level. Blocky lava flows, some of them quite large, form the bulk of the volcano. Neighbouring volcanoes are Nevado San Francisco, the Laguna Amarga

caldera A caldera ( ) 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 str ...

and Laguna Verde volcanoes; additional volcanics are of

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 The Kunstmann edifice probably counts as a separate volcano as well. The volcano has erupted

trachyandesite Trachyandesite is an extrusive igneous rock with a composition between trachyte and andesite. It has little or no free quartz, but is dominated by sodic plagioclase and alkali feldspar. It is formed from the cooling of lava enriched in alkal ...

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

and

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

. The rocks contain

hornblende Hornblende is a complex silicate minerals#Inosilicates, inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common ...

and

pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...

with a total content of 58-61% of SiO₂ and form a

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

-rich

calc-alkaline The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic ...

suite. In some parts of the volcano, its rocks have suffered

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

alteration. Water from the mountain runs into Laguna Verde, which is to its southwest. A number of dates have been obtained on Falso Azufre; with the exception of the oldest ones on the Kunstmann edifice (3.5 to 2.9 million years ago) Falso Azufre has only yielded ages of less than one million years, with older dates found in the western part of the volcano and the younger dates of less than 400,000 years ago in the eastern part; the absolutely youngest date was obtained on a lava flow linked to Dos Conos; 160,000 ± 80,000 years ago. Falso Azufre could thus be considered an extinct volcano, although recent activity cannot be ruled out. While the remoteness of the volcano reduces any hazard potential future pyroclastic eruptions could impact

air traffic Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled ai ...

over the region and east of it; further a major road is close to the volcano. It is considered the 32nd most dangerous volcano out of 38 in Argentina. Falso Azufre is part of the

Central Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South Americ ...

of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

together with about 110 other

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

volcanoes, and lies in the southern sector of the volcanic zone;Grosse, et al. 2018, p. 2 other volcanic zones in the Andes are the

Northern Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South America ...

, the

Southern Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South America ...

and the

Austral Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South Americ ...

.Grosse, et al. 2018, p. 3 The history of volcanic activity is poorly known for most of these volcanoes owing to the lack of dating; only a few historical eruptions have been recorded, such as an eruption at

Ojos del Salado Nevado Ojos del Salado is a Dormant volcano, dormant complex volcano in the Andes on the Argentina–Chile border. It is the highest volcano on Earth and the highest peak in Chile. The upper reaches of Ojos del Salado consist of several overlapp ...

in 1993. It is considered the 32nd of the 38 volcanoes of Argentina by dangerousness.

References

* {{Authority control Volcanoes of Atacama Region Volcanoes of Catamarca Province Complex volcanoes Subduction volcanoes Mountains of Catamarca Province Mountains of Atacama Region Polygenetic volcanoes Argentina–Chile border International mountains of South America Five-thousanders of the Andes

See also

References