Incahuasi

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Incahuasi
Volcan Incahuasi.jpg
Incahuasi volcano as seen from route 60, Fiambala, Argentina
Highest point
Elevation 6,621 or 6,638 m (21,722 or 21,778 ft) [1][2]
Prominence 1,518 m (4,980 ft) [1]
Listing Ultra
Coordinates 27°01′59″S 68°17′46″W / 27.033°S 68.296°W / -27.033; -68.296Coordinates: 27°01′59″S 68°17′46″W / 27.033°S 68.296°W / -27.033; -68.296[2]
Geography
Incahuasi is located in Argentina
Incahuasi
Incahuasi
Location in Argentina, on the border with Chile
Location Catamarca, Argentina -
Atacama, Chile
Parent range Andes
Geology
Mountain type stratovolcanoes and caldera
Last eruption Unknown
Climbing
First ascent 1913 by Walther Penck

Incahuasi (Spanish pronunciation: [iŋkaˈwasi]; possibly from Quechua: inka Inca, wasi house)[3][4] is a volcanic mountain in the Andes of South America. It lies on the border of the Argentine province of Catamarca, and the Atacama Region of Chile. Incahuasi has a summit elevation of 6,621 metres (21,722 ft) above sea level.

The volcano consists of a 3.5-kilometre-wide (2.2 mi) caldera and two stratovolcanoes. Four pyroclastic cones are located 7 kilometres (4.3 mi) to the north-east and produced basalt-andesite lava flows that cover an area of 10 square kilometres (4 sq mi).[5]

Geography and geology[edit]

Incahuasi lies on the border between Argentina and Chile,[2] close to Paso San Francisco.[6] A major road crosses the border there.[7]

Regional[edit]

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 the volcanic zone;[8] other volcanic zones in the Andes are the Northern Volcanic Zone, the Southern Volcanic Zone and the Austral Volcanic Zone.[9] 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 in 1993.[8]

Incahuasi is located northeast of Ojos del Salado,[2] the highest volcano in the world.[10] Both volcanoes are found at the southern end of the Central Volcanic Zone.[11] They together with El Fraile, Cerro El Muerto, Nevado Tres Cruces and El Solo form a 50 kilometres (31 mi) long volcanic chain.[12]

The area is dominated by volcanoes that were active after 1.5 million years ago.[13] Also located close to Incahuasi are Falso Azufre and Nevado San Francisco,[6] as well as the Miocene Cerro Morocho and Cerro Ojo de Las Lozas volcanoes.[14] It has been suggested that a perpendicular chain of volcanoes including Ojos del Salado may be the consequence of the Juan Fernandez Ridge subducting in the Peru-Chile Trench.[15]

Volcanism in the area goes 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.[11]

Local[edit]

Incahuasi is formed by a caldera 3.5 kilometres (2.2 mi) wide. Two coalesced stratovolcanoes formed within the caldera[2] and have a diameter of 15 kilometres (9.3 mi).[16] A 6 by 4 kilometres (3.7 mi × 2.5 mi) wide lava dome is located on the eastern flank.[16] The volcano has a volume of about 231 cubic kilometres (55 cu mi)[17] and covers a surface area of about 207 square kilometres (80 sq mi).[18] With a height of 6,621 metres (21,722 ft) Incahuasi is the 12th highest mountain in South America[19] and one of the world's highest volcanoes.[18]

Incahuasi has two craters, a summit crater and an arcuate crater on the eastern slope that contains a lava dome.[2] The summit crater has dimensions of 750 by 900 metres (2,460 ft × 2,950 ft)[16] and is embedded within a 2 kilometres (1.2 mi) high summit plateau.[14] Subsidiary vents conversely are associated with fissure vents.[20]

The western and southwestern slopes of Incahuasi are dotted with lava domes,[2] which are more subdued than on other volcanoes in the region.[21] Less than 1 kilometre (0.62 mi) wide and 5 kilometres (3.1 mi) long[16] lava flows extend down the volcano.[2] They reach the Las Coladas salar east of Incahuasi.[22] Two 2 kilometres (1.2 mi) long coulees extend north and east of the main crater.[16]

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[2] but they are probably an independent volcanic system, similar to other regional mafic volcanoes.[23] On Incahuasi's eastern flank lies a major lava dome and a field of lava flows.[14] Incahuasi volcano rises over a surface with elevations of 4,300–4,700 metres (14,100–15,400 ft).[24]

Composition[edit]

Like many Andean volcanoes, Incahuasi has erupted andesite containing hornblende and pyroxene,[6] but also trachyandesite and trachydacite.[25] Lava flows on the main stratovolcano are dacitic.[2]

The four cones northeast of the principal volcano have erupted basaltic andesite.[2] Likewise, parasitic cones have erupted magnesium-rich basaltic andesite.[26] Minerals contained in these rocks include clinopyroxene and olivine.[6]

The occurrence of such basic magmas in a volcanic setting dominated by dacites appears to be a consequence of local tectonics, which involve the extension of the crust compared to the compressional regime farther west.[13] Originating in the mantle, the magmas quickly ascended in faults and were contaminated by crustal material.[6] The mantle itself had been modified before by crustal material added by delamination of the lower crust and subduction erosion.[27]

Climate[edit]

Incahuasi does not have glaciers,[24] but it does have at least temporary snowpack.[2] Even the crater does not support the development of glaciers.[28]

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.[24] This aridity is caused by the rain shadow effect of the Subandean Ranges, which block moisture from the Atlantic Ocean.[29]

Eruptive history[edit]

One andesitic lava flow on 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.[30] Based on their preservations, the lava flows appear to be of roughly comparable ages.[16] 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.[31]

Parasitic cones were active over 500,000 years ago.[26] These include 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.[31]

Volcanic activity at Incahuasi may have continued into the Holocene, considering the young appearance of its eruption products[2] 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 is known to occur with long rest phases between eruptions (reaching one million years).[23] There are reports of fumarolic activity. The volcano is considered a potential geological hazard to Argentina[32] and Chile, where the SERNAGEOMIN hazard maps identify it as a potential threat.[33] The remoteness of the volcano means that future eruptions are unlikely to impact populated areas, however.[34]

Climbing history[edit]

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 between 1854-1859 ascended the mountain.[35]

Archeology[edit]

In 1913, an Inca ceremonial structure was found on the summit of Incahuasi.[19]

See also[edit]

References[edit]

  1. ^ a b "Argentina and Chile North: Ultra-Prominences" Peaklist.org. Retrieved 2013-02-25.
  2. ^ a b c d e f g h i j k l m "Nevado de Incahuasi". Global Volcanism Program. Smithsonian Institution. 
  3. ^ Diccionario Quechua - Español - Quechua, Academía Mayor de la Lengua Quechua, Gobierno Regional Cusco, Cusco 2005 (Quechua-Spanish dictionary)
  4. ^ Teofilo Laime Ajacopa, Diccionario Bilingüe Iskay simipi yuyayk'ancha, La Paz, 2007 (Quechua-Spanish dictionary)
  5. ^ http://www.volcanolive.com/incahuasi.html
  6. ^ a b c d e Kay, Coira & Mpodozis 2008, p. 163.
  7. ^ Gspurning, Lazar & Sulzer 2006, p. 60.
  8. ^ a b Grosse et al. 2018, p. 2.
  9. ^ Grosse et al. 2018, p. 3.
  10. ^ Gonzalez-Ferran, Baker & Rex 1985, p. 434.
  11. ^ a b Kay, Coira & Mpodozis 2008, p. 160.
  12. ^ Kay, Mpodozis & Gardeweg 2014, p. 310.
  13. ^ a b Kay, Coira & Mpodozis 2008, p. 162.
  14. ^ a b c Grosse et al. 2018, p. 11.
  15. ^ Gonzalez-Ferran, Baker & Rex 1985, p. 425.
  16. ^ a b c d e f Grosse, P.; Orihashi, Y.; Guzman, S.; Petrinovic, I. (2014). "Volcanismo Cuaternario en la Zona del Paso San Francisco, Catamarca". conicet.gov.ar (in Spanish). 
  17. ^ Aravena, Diego; Villalón, Ignacio; Sánchez, Pablo (April 2015). "Igneous Related Geothermal Resources in the Chilean Andes" (PDF). pangea.stanford.edu. p. 5. 
  18. ^ a b Grosse et al. 2018, p. 10.
  19. ^ a b Rundel & Kleier 2014, p. 3.
  20. ^ Seggiaro, R. E.; Hongn, F. D. (1999-01-01). "Influencia tectónica en el volcanismo Cenozoico del Noroeste argentino". Acta geológica hispánica. 34 (2): 229. ISSN 2173-6537. 
  21. ^ Gonzalez-Ferran, Baker & Rex 1985, p. 436.
  22. ^ Valero-Garcés et al. 2000, p. 345.
  23. ^ a b Grosse et al. 2018, p. 18.
  24. ^ a b c Gspurning, Lazar & Sulzer 2006, p. 61.
  25. ^ Grosse et al. 2018, p. 7.
  26. ^ a b Mpodozis, Constantino; Cornejo, Paula; Kay, Suzanne M.; Tittler, Andrew (1995-12-01). "La Franja de Maricunga: sintesis de la evolucion del Frente Volcanico Oligoceno-Mioceno de la zona sur de los Andes Centrales". Andean Geology (in Spanish). 22 (2): 308. ISSN 0718-7106. 
  27. ^ Kay, Mpodozis & Gardeweg 2014, p. 324.
  28. ^ Gspurning, Lazar & Sulzer 2006, p. 63.
  29. ^ Valero-Garcés et al. 2000, p. 344.
  30. ^ Gonzalez-Ferran, Baker & Rex 1985, p. 435.
  31. ^ a b Grosse et al. 2018, p. 12.
  32. ^ Perucca, Laura P.; Moreiras, Stella M. (2009-01-01). Latrubesse, Edgardo M., ed. Developments in Earth Surface Processes. Natural Hazards and Human-Exacerbated Disasters in Latin America. 13. Elsevier. p. 292. 
  33. ^ "Peligros Volcanicos" (PDF). sernageomin.cl. 2011. ISSN 0717-7305. 
  34. ^ Grosse et al. 2018, p. 19.
  35. ^ Echevarria, Evelio (1987). "Early British Ascents in the Andes (1831-1946)" (PDF). Alpine Journal: 64–65. 

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