Andagua volcanic field
[15] Lava flows reach lengths of 20 kilometres (12 mi) and thicknesses of 80 metres (260 ft); their surfaces are blocky and feature channels.
[24] Among the vents are: Older volcanic landforms are vegetated and have developed a soil cover,[2] and sometimes are altered by river[15] or glacial erosion or have been converted into farmland.
[36]The volcanic field has erupted rocks ranging from basaltic andesite to dacite, with composition varying from one individual volcano to the other[2] but dominantly sodic[38] although it has also been described as potassic owing to the poassium-silica ratio.
[39] Generally, the rocks fall into the categories benmoreite, latite and mugearite[21] with rare andesite and basalt.
[22] Phenocrysts include hornblende, olivine, plagioclase and pyroxene and less commonly alkali feldspar and biotite,[21] and xenoliths have been reported as well.
[46] Small volcanoes such as these of the Andagua volcanic field are a subordinate part of the Peruvian Central Volcanic Zone; most volcanoes are large[4] and among these is Sabancaya with historical activity, El Misti with solfataric activity, Coropuna, which is the highest volcano in Peru and features Holocene activity,[1] Firura and Solimana north and west from Coropuna, and Mismi, Hualca Hualca, Ampato, Chachani and Pichu Pichu.
[56] Humid periods have occurred recently, including two around 600 and 1000 AD linked to El Nino phenomena.
[55] Vegetation in the region includes alder, cacti, eucalyptus, ichu grass, Polylepis trees, tola shrubs, pillow-shaped yareta.
[57] The exact vegetation type varies with elevation,[58] defining four life zones:[57] The Laguna Mamacocha and Chachas are populated by fish and form oases.
[55] Crops cultivated in the area, especially at Ayo and Andagua, include barley, broad bean, corn, lucerne, potatoes and wine.
[57] The oldest activity of the Andagua volcanic field occurred between 400,000 and 64,000 years ago and has been identified close to Chivay in the Colca Valley.
[6] The youngest eruptions occurred along the Jenchana-Ninanmama fault[25] and the most recent event was dated to 370 years ago and took place at Chilcayoc Chico.
[61] Explosive eruptions could result in fallout of lava bombs, tephra and volcanic ash, but the impact would be limited to the surroundings of the vent, probably less than 6 kilometres (3.7 mi).
The volcanic field however also produced lava flows in the past, which can reach larger distances and also infrastructure such as the Mantaro-Socabaya power line and could also bury the ground for perhaps thousands of years.
[73] A geopark was created in 2015[74] and by UNESCO in 2019,[75] some volcanoes of the Andagua volcanic field are considered to be geosites[76] with some spots already protected in some way; the area is of value from the perspectives of both geotourism and science.
