Ojos del Salado
Encyclopedia
Nevado Ojos del Salado is a massive stratovolcano
Stratovolcano
A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...

 in the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 on the Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

-Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 border and the highest volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 in the world at 6891 metres (22,608 ft). It is also the second highest mountain in the Western Hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...

 and Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 and the highest in Chile. It is located about 600 kilometres (372.8 mi) north of Aconcagua
Aconcagua
Aconcagua is the highest mountain in the Americas at . It is located in the Andes mountain range, in the Argentine province of Mendoza and it lies west by north of its capital, the city of Mendoza. The summit is also located about 5 kilometres from San Juan Province and 15 kilometres from the...

, the highest mountain in the Western Hemisphere at 6962 m (22,841 ft).

Due to its location near the Atacama desert, the mountain has very dry conditions with snow only remaining on the peak during winter. Despite the generally dry conditions, there is a permanent crater lake
Crater lake
A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...

 about 100 metres (328.1 ft) in diameter at an elevation of 6390 m (20,964.6 ft) on the eastern side of Ojos del Salado. This is most likely the highest lake of any kind in the world.

The ascent of Ojos del Salado is mostly a hike except for the final section to the summit which is a difficult scramble that may require ropes. The first ascent was made in 1937 by Jan Alfred Szczepański and Justyn Wojsznis, members of a Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 expedition in the Andes.

Its name comes from the enormous deposits of salt that, in the form of lagoons or “eyes”, appear in its glaciers.

Volcanic activity

There is no doubt that Ojos del Salado is a recently active volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

, but the question of whether it should be considered currently (or "historically") active is arguable. According to the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

's Global Volcanism Program
Global Volcanism Program
The Smithsonian Institution's Global Volcanism Program documents Earth's volcanoes and their eruptive history over the past 10,000 years. The GVP reports on current eruptions from around the world as well as maintaining a database repository on active volcanoes and their eruptions. In this way, a...

, the most recent known eruption was around 1300 years ago, with large error bars. However, there is also some evidence for a minor ash emission in 1993, which would definitely qualify the volcano as historically active. The presence of fumarole
Fumarole
A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

s high on the mountain and recent-looking lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 flows, albeit of uncertain age, also argues in favor of a categorization as "active." By these definitions Ojos del Salado is the highest historically active volcano on earth. If the older date is accepted, the title of "highest historically active volcano" might reside instead with the somewhat lower Llullaillaco
Llullaillaco
Llullaillaco is a stratovolcano at the border of Argentina and Chile. It lies in the Puna de Atacama, a region of very high volcanic peaks on a high plateau within the Atacama Desert, one of the driest places in the world...

 volcano, which certainly has erupted in historic times (most recently in 1877) and should still be considered active. Definitions of "active" being themselves controversial and somewhat arbitrary, the point is mainly of trivial interest.

Composition

Salado's rock is predominantly potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

-rich dacite
Dacite
Dacite is an igneous, volcanic rock. It has an aphanitic to porphyritic texture and is intermediate in composition between andesite and rhyolite. The relative proportions of feldspars and quartz in dacite, and in many other volcanic rocks, are illustrated in the QAPF diagram...

 and rhyodacite
Rhyodacite
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of granodiorite. Phenocrysts of sodium rich plagioclase, sanidine, quartz, and biotite or hornblende are typically set in an aphanitic to glassy light to intermediate...

. Its lavas are high in biotite
Biotite
Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula . More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous endmembers...

, hornblende
Hornblende
Hornblende is a complex 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....

, plagioclase
Plagioclase
Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...

, and opaques
Opaques
-Track listing:Side A#"Milena Jesenska" - 5:40#"Cyst" - 4:22#"Anatomy" - 5:09#"Enfilade" - 4:54#"Afrikaner" - 1:08Side B#"Taoist" - 18:57...

, with lower levels of augite
Augite
Augite is a single chain inosilicate mineral, 2O6. The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.-Characteristics:Augite is a solid solution in the pyroxene group...

, quartz, and hypersthene
Hypersthene
Hypersthene is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes. Many references have formally abandoned this term, preferring to categorise this mineral as enstatite or ferrosilite. It is found in igneous and some metamorphic rocks as well as in stony and...

.

Elevation

The elevation of Ojos del Salado has been the subject of debate. Contrary to widely reproduced claims made by Argentine authorities in 1994, which still appear in some maps, publications and websites, Ojos del Salado is about 100 m (328.1 ft) higher than Argentina's nearby Monte Pissis
Monte Pissis
Monte Pissis is an extinct volcano in La Rioja Province, Argentina. The mountain is the third-highest in the Western Hemisphere, and is located about 550 km north of Aconcagua....

 (6,793 m).

An article in Andes magazine in 2006 offered that Ojos del Salado may be higher than Aconcagua
Aconcagua
Aconcagua is the highest mountain in the Americas at . It is located in the Andes mountain range, in the Argentine province of Mendoza and it lies west by north of its capital, the city of Mendoza. The summit is also located about 5 kilometres from San Juan Province and 15 kilometres from the...

, Argentina, although the argument was premised on older, less accurate altitude surveys. The results of these older surveys assigned Ojos del Salado an elevation of 7057 metres (23,152.9 ft), which would have made it nearly 100 m (328.1 ft) higher than Aconcagua. As early as 1955, an estimate was made that the elevation of Ojos del Salado was 7100 m (23,294 ft), but that was "simply an estimate based on the altitude of the final camp, and the hours of ascent to the summit." In 1956 the first Chilean expedition led by the retired lieutenant
Lieutenant
A lieutenant is a junior commissioned officer in many nations' armed forces. Typically, the rank of lieutenant in naval usage, while still a junior officer rank, is senior to the army rank...

 René Fajardo measured the height of Ojos del Salado as 7,084 m with a pocket pressure altimeter
Altimeter
An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.-Pressure altimeter:...

. Apart from being an inexact method, the height shown by the altimeter was far too high as air pressure is generally lower in the afternoon, the time at which the expedition reached the summit.

In 2007, a Chilean-European expedition performed a survey on both Ojos del Salado and Monte Pissis
Monte Pissis
Monte Pissis is an extinct volcano in La Rioja Province, Argentina. The mountain is the third-highest in the Western Hemisphere, and is located about 550 km north of Aconcagua....

, using more accurate instruments. It found the former to be 6,891 m and the latter 6,793 m. This is within recent handheld Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 (GPS) surveys, which have estimated the mountain to be between 6,880 and 6,910 m (22,570–22,670 ft), although the vertical margin of error of the Chilean-European expedition's equipment, 10 m, leaves uncertainty as to the mountain's more precise altitude.

Motorized partial ascent

Ojos del Salado has been a popular mountain for attaining the highest altitude aboard a land vehicle. Three consecutive records were set here by German expeditions with several vehicles, setting a mark of 6646 m (21,804 ft) by March 2007. On 21 April 2007, Gonzalo Bravo G. and Eduardo Canales Moya from Chile beat such record (6688 m (21,942 ft)). This high altitude record was certified by the Guinness Book of World Records on July 2007..

See also

  • List of volcanoes in Argentina
  • List of volcanoes in Chile
  • List of volcanoes
  • Volcanic Seven Summits
    Volcanic Seven Summits
    The Volcanic Seven Summits are the highest volcanoes on each of the seven continents, just as the Seven Summits are the highest peaks on each of the seven continents...

  • Nevado Tres Cruces
    Nevado Tres Cruces
    Nevado Tres Cruces is a massif of volcanic origin in the Andes Mountains. It has two main summits, Tres Cruces Sur at 6,749 m and Tres Cruces Central at 6,629 m and a third more minor summit, Tres Cruces Norte 6030m. The former marks the border between Argentina and Chile...

  • Incahuasi
    Incahuasi
    Incahuasi or Nevado de Incahuasi is a mountain between the Argentine province of Catamarca, and the Atacama Region of Chile. Located at approximate coordinates , it has a height of 6,621m....

  • Tipas
    Tipas
    Cerro Tipas is a massive complex volcano in northwestern Argentina, located just southwest of Ojos del Salado, the highest volcano in the world. Tipas itself is perhaps the third highest active volcano in the world, and it consists of stratovolcanoes, lava domes, and lava flows.-Source:*...

  • Cerro El Muerto
    Cerro El Muerto
    Cerro el Muerto is a mountain peak of South America and is part of the Andes mountain range. It is also known as the 16th of the largest mountain peaks in the Argentine-Chilean border at...

  • Cerro Solo
    Cerro Solo
    Cerro Solo is a large stratovolcano on the border between Argentina and Chile, west of Ojos del Salado. It consists of nine eruptive centers and is covered in light-colored rhyodacite pyroclastic flow deposits....

  • Laguna Verde

External links

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