Ojos del Salado

Ojos del Salado
sergejf · CC BY-SA 2.0 · source
Name	Ojos del Salado
Elevation m	6889
Prominence m	6392
Range	Andes
Location	Argentina–Chile border
First ascent	1937 (first recorded)
Coordinates	27°06′S 68°32′W

Ojos del Salado is the highest active volcano and the second-highest mountain in the Western Hemisphere, straddling the Argentina–Chile border in the Andes, with an elevation often cited near 6,889–6,930 metres. The massif lies within the Atacama Region and the Catamarca province, adjacent to prominent features such as the Puna de Atacama plateau, Laguna Verde, and Copiapó River headwaters. The peak is notable for extreme aridity, high relative prominence, and a summit crater that hosts permanent snow and ice despite hyperarid surroundings.

Geography and geology

The mountain occupies the central Andes between the Cordillera de la Costa and the Altiplano, forming part of the Andes volcanic arc influenced by subduction of the Nazca Plate beneath the South American Plate. The edifice sits near regional landmarks including Llullaillaco, Nevado Ojos del Salado, Cerro Tres Cruces, Salar de Atacama, and Paso de San Francisco. Local administrative jurisdictions encompass Atacama Region, Catamarca Province, and La Rioja Province. Geological mapping links the massif to Miocene–Pliocene calc-alkaline volcanic centers like Copiapó volcano and Incahuasi. Stratigraphy shows layered andesites, dacites, and basaltic-andesites with extensive pyroclastic deposits analogous to sequences at Licancabur, Llullaillaco, and Pular.

Volcanic activity and eruption history

Volcanological studies place the main eruptive phases in the late Miocene to Pleistocene, with Holocene fumarolic activity documented on the summit. Geochemical analyses compare magmas to those from Lascar, Láscar, Lastarria, Sairecabur and Cordon del Azufre. Radiometric ages from potassium-argon and argon-argon work correlate with eruptions at Cerro Blanco and regional ignimbrites such as the Toba-style sulfur-rich sequences noted across the Puna. Historical records and instrumental monitoring cite fumarolic temperatures and gas emissions resembling activity at Stromboli, Etna, and Popocatépetl, though no confirmed explosive eruptions in recorded history match large Plinian events like Mount Pinatubo or Mount St. Helens.

Glaciers, hydrology, and summit crater

Despite hyperaridity of the Atacama Desert, permanent snowfields and small glaciers occur on shaded flanks, sharing characteristics with glaciers on Nevado Ojos del Salado adjacent peaks like Tres Cruces and Cerro Bonete. The summit crater contains perennial ice and a high-elevation crater lake reported by explorers, comparable to high-elevation bodies such as the lake on Llullaillaco and lakes in the Altiplano. Meltwater contributes to endorheic basins including the Salar de Maricunga and feeds ephemeral streams connecting with the Copiapó River and Salado River catchments. Isotope hydrology draws parallels with studies at Salar de Uyuni and Laguna Verde (Atacama), showing ancient groundwater recharge and limited recharge rates.

Climate and environment

Climatologically the massif is dominated by the Atacama Desert rain shadow, strong diurnal temperature ranges, and persistent high-altitude solar radiation akin to conditions at Chajnantor Observatory and ALMA. Atmospheric studies reference radiosonde and meteorological station data comparable to Puna de Atacama sites and research at Mount Everest base camp for high-altitude hypoxia. Ultraviolet index, wind regimes, and precipitation patterns are similar to those influencing ecosystems at Salar de Atacama, Altiplano, and Puna de Atacama research stations operated by institutions like Universidad de Chile and Universidad Nacional de San Juan.

Human history and exploration

Indigenous presence in surrounding landscapes involves cultures such as the Atacameño people and Diaguita whose archaeological sites, ceremonial platforms, and high-altitude shrines connect to broader Andean ritual landscapes including Tiwanaku, Inca Empire, and sites on Llullaillaco. European and scientific exploration began with Spanish colonial expeditions and later mountaineering by figures linked to German Alpine Club, British Alpine Club, and South American mountaineers from Argentina and Chile. Recorded ascents in the 20th century involved climbers from institutions such as Servicio Nacional de Geología y Minería and mountaineering clubs; logistical approaches echo operations at Aconcagua, Huascarán, and Chimborazo.

Flora and fauna

Biological surveys identify sparse high-elevation biota analogous to flora on the Altiplano and Puna: cushion plants, Azorella-like mats, and hardy taxa comparable to those recorded near Licancabur and Salar de Atacama. Faunal observations include transient populations of vicuña, guanaco, Andean condor, and endemic invertebrates with ecological parallels to species at Las Cuevas and Reserva Nacional Llanos de Challe. Microbial extremophiles found in summit snow and crater lake sediments have been studied similarly to microbes from Mount Erebus, McMurdo Dry Valleys, and high-altitude sites investigated by researchers affiliated with CONICET and Pontifical Catholic University of Chile.

Access, routes, and mountaineering

Access is typically from Argentine towns such as Fiambalá and Chilean access points near Copiapó and Maricunga Pass, with logistics comparable to expeditions to Ojos del Salado-region peaks like Volcán Laguna Verde and Cerro El Muerto. Popular routes approach via the northwest and northeast faces, base camps use high-altitude refuge huts similar to those on Aconcagua and guided by companies linked to Federación Argentina de Ski y Andinismo and Federación de Andinismo de Chile. Climbers contend with altitude sickness protocols established in mountaineering literature from American Alpine Club, use acclimatization strategies akin to those for Denali and Mount Kilimanjaro, and require permits from provincial and regional authorities such as Dirección de Aguas and national park services. Category:Mountains of the Andes