Ojos del Salado

Ojos del Salado
The Chilean summit viewed from the Argentine summit.
Elevation	6,893 m (22,615 ft) [1]
Prominence	3,688 m (12,100 ft) [1] Ranked 43rd
Listing	Volcanic Seven Summits Seven Second Summits Country high point Ultra
Location
Ojos del Salado  Chile and  Argentina
Range	Andes
Coordinates	27°06′34.6″S 68°32′32.1″W / 27.109611°S 68.54225°W / -27.109611; -68.54225Coordinates: 27°06′34.6″S 68°32′32.1″W / 27.109611°S 68.54225°W / -27.109611; -68.54225
Geology
Type	Stratovolcano
Last eruption	700 AD ± 300 years[2]
Climbing
First ascent	February 26, 1937 Jan Alfred Szczepański Justyn Wojsznis
Easiest route	Scramble

Nevado Ojos del Salado ("Source of the Salt river" summit) is a massive stratovolcano in the Andes on the Argentina-Chile border and the highest volcano in the world at 6,891 metres (22,608 ft). It is also the second highest mountain in the Western Hemisphere and Southern Hemisphere and the highest in Chile. It is located about 600 kilometres (370 mi) north of Aconcagua, the highest mountain in the Western Hemisphere at 6,962 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 about 100 metres (300 ft) in diameter at an elevation of 6,390 m (20,960 ft) on the eastern side of Ojos del Salado.^[3] 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 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.^[4]

Volcanic activity

There is no doubt that Ojos del Salado is a recently active volcano, but the question of whether it should be considered currently (or "historically") active is arguable. According to the Smithsonian Institution's Global Volcanism Program,^[2] 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 fumaroles high on the mountain and recent-looking lava 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 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-rich dacite and rhyodacite. Its lavas are high in biotite, hornblende, plagioclase, and opaques, with lower levels of augite, quartz, and hypersthene.^[5]

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 (330 ft) higher than Argentina's nearby Monte Pissis (6,793 m).

An article in Andes magazine in 2006 offered that Ojos del Salado may be higher than Aconcagua, 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 7,057 metres (23,150 ft), which would have made it nearly 100 m (330 ft) higher than Aconcagua. As early as 1955, an estimate was made that the elevation of Ojos del Salado was 7,100 m (23,000 ft), but that was "simply an estimate based on the altitude of the final camp, and the hours of ascent to the summit."^[6] In 1956 the first Chilean expedition led by the retired lieutenant René Fajardo measured the height of Ojos del Salado as 7,084 m with a pocket 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.^[7]

In 2007, a Chilean-European expedition performed a survey on both Ojos del Salado and Monte Pissis, using more accurate instruments. It found the former to be 6,891 m and the latter 6,793 m.^[8] This is within recent handheld Global Positioning System (GPS) surveys, which have estimated the mountain to be between 6,880 and 6,910 m (22,570–22,670 ft),^[9] although the vertical margin of error of the Chilean-European expedition's equipment, 10 m,^[8] leaves uncertainty as to the mountain's more precise altitude.

Motorized partial ascent

The modified vehicle used in the 2007 expedition.

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 6,646 m (21,804 ft) by March 2007. On 21 April 2007, Gonzalo Bravo G. and Eduardo Canales Moya from Chile beat such record (6,688 m (21,942 ft)). This high altitude record was certified by the Guinness Book of World Records on July 2007.^[10].

See also

• List of volcanoes in Argentina
• List of volcanoes in Chile
• List of volcanoes
• Volcanic Seven Summits
• Nevado Tres Cruces
• Incahuasi
• Tipas
• Cerro El Muerto
• Cerro Solo
• Laguna Verde

References

• González-Ferrán, Oscar (1995). Volcanes de Chile. Santiago, Chile: Instituto Geográfico Militar. p. 640 pp. ISBN 956-202-054-1.  (in Spanish; also includes volcanoes of Argentina, Bolivia, and Peru)
• De Silva, Shanaka L.; Francis, Peter (1991). Volcanoes of the Central Andes. Springer-Verlag. p. 216 pp. ISBN 3540537066. 
• Biggar, John (2005). The Andes: A Guide for Climbers (3rd ed.). Andes Publishing (Scotland). p. 304 pp. ISBN 0-9536087-2-7. http://www.andes.org.uk/andes-guidebooks.asp. 

1. ^ ^{a b} Andes ultra-prominent peaks on peaklist.org
2. ^ ^{a b} "Ojos del Salado". Global Volcanism Program, Smithsonian Institution. http://www.volcano.si.edu/world/volcano.cfm?vnum=1505-13=. 
3. ^ Andes Website - Information about Ojos del Salado volcano, a high mountain in South America and the World's highest volcano
4. ^ [1]
5. ^ "Nevados Ojos del Salado". Volcano World. Oregon State University. 2011. http://volcano.oregonstate.edu/oldroot/CVZ/ojossalado/index.html. Retrieved July 29, 2011. 
6. ^ American Alpine Journal, 1956, p. 134; quoting the "Boletin Informativo No. 16" (June 1955) of the Argentine Associación Tucumana de Andismo.
7. ^ Nieves y Glaciares de Chile: Fundamentos de glaciología, 1956, Luis Lliboutry
8. ^ ^{a b} Phillipe Reuter: "El Ojos del Salado es 100 metros más alto que el Pissis"
9. ^ SummitPost climber's log, which includes handheld GPS estimates
10. ^ http://www.izook.com/features/record/record.htm

External links

• 1 December 2006 Star Trails at 19,000 Feet - NASA Astronomy Picture of the Day
• Andes information
• Peak bagger
• Summit post
• Peak list