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| Volcanic fields of the Andes | |
|---|---|
| Name | Andes Volcanic Fields |
| Location | Andes |
| Type | Volcanic fields |
| Highest | Ojos del Salado |
| Region | South America |
| Countries | Argentina, Chile, Bolivia, Peru, Ecuador, Colombia |
Volcanic fields of the Andes are widespread clusters of vents, cones, domes, and lava flows that punctuate the Andes from Colombia to Tierra del Fuego. These volcanic fields record interactions between the Nazca Plate, South American Plate, and intraplate processes linked to regional structures such as the Peru–Chile Trench and the Altiplano. They host diverse features ranging from monogenetic cones to composite volcanoes like Cotopaxi and Ojos del Salado, and play roles in hazards, mineral resources, and paleoclimatic records relevant to Instituto Geofísico del Perú, Servicio Nacional de Geología y Minería (Chile), and global volcanology programs.
The Andean volcanic fields form part of the Pacific Ring of Fire and include volcanic provinces such as the Central Volcanic Zone, Northern Volcanic Zone, Southern Volcanic Zone, and the Austral Volcanic Zone. Key volcanic centers include Llullaillaco, Lascar, Parinacota, Mount Chimborazo, and Reventador, documented by agencies like Servicio Geológico Colombiano and research from institutions such as the Smithsonian Institution and US Geological Survey. The fields vary in age from Neogene to Holocene and are influenced by crustal thickness variations present across the Altiplano-Puna plateau and Patagonian Andes.
Andean volcanism is governed by subduction of the Nazca Plate beneath the South American Plate at convergent margins including the Peru–Chile Trench and the Ecuador–Colombia subduction zone. Along-strike segmentation produces the Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and discontinuous Austral Volcanic Zone, with control by structures such as the Atacama Fault and the Liquiñe-Ofqui Fault. Slab geometry variations, including flat-slab segments beneath Peru and Argentina, and slab roll-back beneath Chile and Ecuador, modulate melting, producing magmatism recorded in the Altiplano-Puna Magma Body and magmatic systems beneath Antofagasta and San Pedro de Atacama.
Volcanic fields range from dense monogenetic provinces like the Payún Matrú and San José complexes to broad silicic volcanic fields such as the Altiplano-Puna Volcanic Complex and caldera systems including Los Cóndores and Sangay. In the north, volcanic fields around Ecuador and Colombia include Guagua Pichincha, Cumbal, and Nevado del Ruiz clusters; central Andes fields encompass Cerro Galán, Atana, and Purico Complex; southern fields include Chaitén-associated vents and the Lauricocha province. Distribution correlates with crustal thickness under regions like the Puna Plateau and tectonic steps near the Isla Robinson Crusoe area.
Eruption styles range from effusive basaltic fissure eruptions similar to those observed at Nevado del Huila vents to explosive Plinian eruptions at Tungurahua, Cotopaxi, and Puyehue-Cordón Caulle. Monogenetic scoria cones, maar-forming phreatomagmatic events, dome extrusion as at Chimborazo, and large ignimbrite-forming eruptions from calderas such as Cerro Galán characterize the fields. Eruptive behavior is influenced by magma composition, volatile content, and crustal assimilation processes documented in studies by International Association of Volcanology and Chemistry of the Earth's Interior researchers and regional observatories like the Instituto Geofísico (Ecuador).
Andean volcanic field magmas span basalts to rhyolites, with calc-alkaline affinities dominant in arc segments; examples include andesites at Lascar and dacites at Los Frailes. Geochemical signatures reflect slab-derived fluids, mantle wedge metasomatism, and crustal contamination evidenced in isotopic systems (Sr-Nd-Pb) studied at Universidad de Chile, Universidad Nacional de San Juan, and CONICET laboratories. The Central Volcanic Zone hosts high-K calc-alkaline and shoshonitic suites near Antofagasta de la Sierra, whereas the Southern Volcanic Zone exhibits transitional compositions linked to variable subduction angle and slab dehydration documented in papers from Geological Society of America meetings.
Volcanic fields produce hazards including ash fall impacting cities like Quito, lahars affecting valleys near Riobamba, pyroclastic flows from dome collapse at Tungurahua, and long-range aviation hazards exemplified by the 2011 Puyehue-Cordón Caulle eruption. Monitoring is undertaken by entities such as Servicio Nacional de Geología y Minería (Chile), Instituto Geofísico del Perú, Servicio Geológico Colombiano, and international partners like the Volcanic Ash Advisory Center network and UN Office for Disaster Risk Reduction. Risk mitigation integrates seismic monitoring, satellite remote sensing from NASA missions, GPS deformation networks, and hazard mapping by national emergency agencies such as ONEMI.
Volcanic fields contribute mineral endowments including porphyry and epithermal deposits exploited near Chuquicamata, Zaldívar, and El Indio, supporting companies like Compañía Minera Doña Inés de Collahuasi and BHP. Fertile volcanic soils in regions such as the Ecuadorian Andes and Cuyo bolster agriculture around Latacunga and Mendoza. Conversely, eruptions disrupt air transport affecting carriers operating from Santiago de Chile and Buenos Aires, impact hydrology of basins like the Bío Bío River and Maipo River, and alter ecosystems in Páramo and Valdivian temperate rainforest zones. Long-term volcanic landscapes also offer geothermal potential explored by developers and agencies including Enap and international energy partners.
Category:Volcanism of South America