Aracar

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title: "Aracar" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["stratovolcanoes-of-argentina", "subduction-volcanoes", "active-volcanoes", "mountains-of-argentina", "volcanic-crater-lakes", "polygenetic-volcanoes", "six-thousanders-of-the-andes", "puna-de-atacama", "pliocene-stratovolcanoes", "pleistocene-stratovolcanoes"] description: "Mountain in Argentina" topic_path: "geography/argentina" source: "https://en.wikipedia.org/wiki/Aracar" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Mountain in Argentina ::

::data[format=table title="Infobox mountain"]

Field	Value
name	Aracar
photo	Aracar.jpg
photo_caption	Aracar from the Space Shuttle, January 2003
elevation_m	6095
elevation_ref
parent_peak	Ojos del Salado
prominence_m	1791
prominence_ref
listing	Ultra
location	Argentina
range	Andes
map	Argentina
map_size	230
label_position	right
coordinates
coordinates_ref
type	Stratovolcano
age	Pliocene
last_eruption	1993
first_ascent	04/01/1958 - Yosko Cvitanic (Yugoslavia), Gustav Lanstchner and Emo Henrich (Austria)
::

| name = Aracar | photo = Aracar.jpg | photo_caption = Aracar from the Space Shuttle, January 2003 | elevation_m = 6095 | elevation_ref = | parent_peak = Ojos del Salado | prominence_m = 1791 | prominence_ref = | listing = Ultra | location = Argentina | range = Andes | map = Argentina |relief=1 | range_coordinates = | map_size = 230 | map_caption = | label_position = right | coordinates = | coordinates_ref = | topo = | type = Stratovolcano | age = Pliocene | last_eruption = 1993 | first_ascent = 04/01/1958 - Yosko Cvitanic (Yugoslavia), Gustav Lanstchner and Emo Henrich (Austria) | easiest_route =

Aracar is a large conical stratovolcano in northwestern Argentina, just east of the Chilean border. It has a main summit crater about 1 - in diameter and sometimes contains crater lakes and a secondary crater. The volcano has formed, starting during the Pliocene, on top of a lava platform and an older basement. Constructed on a base with an altitude of 4100 m, it covers a surface area of 192.4 km2 and has a volume of 148 km3. The only observed volcanic activity was a possible steam or ash plume on March 28, 1993, seen from the village of Tolar Grande about 50 km southeast of the volcano, but with no evidence of deformation of the volcano from satellite observations. Inca archeological sites are found on the volcano.

Geology

Aracar is located in the Salta province, north of the Salar de Taca Taca and Arizaro and east of the Salar de Incahuasi and the Sierra de Taca Taca, close to the Chilean border. The name is also spelled Arakar. Volcanoes in the territory rise above the endorheic sinks and landscape. Cerro Arizaro (9.0 ± 1.3 mya) is another volcano southeast of Aracar.

The basement consists of Paleozoic granites. The Laguna de Aracar Formation north of Aracar was formed by Gondwana volcanism and has been dated by K-Ar methods to be 266 ± 28 Ma old; it is associated with the Llullaillaco Unit. Tertiary sedimentary rocks in the east and arenites in the south form the rest of the basement. The volcano's height over the surrounding terrain is between 1900 - from north to south.

Aracar is a polygenetic volcanic cone with a diameter of 13.5 km and a rectangular basis of 12 -, covering a surface area of 192.4 km2. Four lava domes extend southeast from the volcano. Grey basaltic lava flows descend from its summit, forming a gentle western flank and much steeper eastern, northern, and southern flanks. West of the main summit, a 1 - wide and several hundred meters deep crater forms Aracar's main crater. Snowmelt occasionally forms small ephemeral lakes in the main crater. A 100 m shallow 10 m deep secondary crater is surmounted by a flat semilunar 15 - wide surface. Small southbound andesitic lava flows are associated with the main crater. There are traces of a sector collapse in form of an irregular landslide scar and a landslide deposit, but the landslide deposit may be associated with the collapse of Pular instead. Some deep gorges cut into the volcano, and erosion has removed 1.8 km3 of rock. Moraines, mainly occurring on the volcano's eastern side, descend to 4500 m.

A lava field is found beneath the Aracar volcano. It is constructed by lava flows that range in composition from basaltic andesite bordering on trachyandesite over dacite and smaller flows of partially silicic magma. Basal lava flows are heavily eroded and reach 14 km in length and width in the south, decreasing from 4.5 km to 1.5 km. They have cancelled out the prior landscape. These lower lava flows reach the Salar de Taca Taca and extend south-southeast. The main andesitic cone is 900 m high and 5 km wide, forming on top of older dacitic lava flows. The dacite flows which form the edifice's bulk are covered with debris and have flow fronts 20 - high. The lava field formed over a north-south slope.

Lavas have gray-black porphyric and in some places, vesicular textures. Andesine-labradorite plagioclase and pyroxene phenocrysts are found in the lavas, which have a fine-grained groundmass. Apatite, augite, and opaque mineral inclusions are also seen. Some lava flows display very small-scale flow bands with feldspat and plagioclase inclusions. Xenoliths containing quartz and gabbro nodules also play a part in the rock composition. The overall rock composition is calc-alkaline, similar to other magmas in the Central Volcanic Zone, with some intraplate and crustal components, with the magmas forming in an open magma chamber. Later magmas may have been influenced by the entry of basic magmas from the depth. The total volume of the edifice is about 148 km3.

The volcanic history of Aracar is poorly understood. The bottom lava flows have ages of 3.4 ± 1.2 to 2.6 ± 0.4 mya, but an age of 100,000 years has also been given. Presumably, at first, fluid basaltic lavas were erupted. Subsequently, dacite lavas erupted, accompanied by the formation of a strong slope in the edifice and hydrothermal activity at a northwestern lava dome. Finally, the central crater and andesite lava flows were erupted. Beneath 4500 m altitude, lava flows are well conserved. No historical activity is recorded but in March 1993, inhabitants of Tolar Grande 50 km southeast of Aracar observed a high ash or steam column rising from Aracar, which may be either an eruption or the result of landslides. Satellite images did not detect edifice deformation during this episode, probably due to aliasing. Aracar is considered Argentina's 17th most dangerous volcano out of 38.

History and human interaction

The mountain was climbed in 1958 by European climbers, including Mathias Rebitsch, who found an archeological site in the summit area. Minefield are present on the northeastern flanks of Aracar, making exploration from that side impossible. A major Inca archeological site is found in Aracar. Two separate places exist on the summit and secondary crater. The summit place is formed by a stone circle and low stone walls which are placed just above the slopes down into the main crater. A terrace-shaped stone structure forms the secondary crater, which is placed on its slopes. A smaller terrace is located on its northeastern side. Timber and wood are found around the stone structures. All these sites have no more than 5 m dimensions. These structures may be sanctuary sites that could be accessed by a bystanding public during ceremonies, with the sites themselves located within wind protected areas.

Notes

References

References

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2. "ASTER GDEM Project".
3. "Copernicus Space Component Data Access".
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17. (October 1997). "Geología del volcán Aracar. Sur de los Andes Centrales -24o19'00"S, 67o49'20"0- Argentina". Congreso Geológico Chileno, 8..
18. "Aracar, Guanaquero, Rincón, Arizaro y Blanco: Prospección y relevamiento de santuarios de altura en volcanes de la Puna occidental salteña (República Argentina)". Sociedad Argentina de Antropología.
19. (30 May 2014). "Geoquímica, dataciones U-Pb SHRIMP sobre circón e isótopos de Hf del magmatismo gondwánico en el NW de Argentina: petrogénesis e implicancias geodinámicas.". Andean Geology.
20. (1997). "Geología de las efusiones basales del volcán Aracar, Puna Salteña, República Argentina". Congreso Geológico Chileno, 8..

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