Apacheta-Aguilucho volcanic complex (also known as Cerro Pabellón) is a

volcanic complex A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. They may form due to changes in eruptive habit or ...

in Chile. It consists of two volcanoes Cerro Apacheta and Cerro Aguilucho, which are constructed mainly by

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

s and surrounded by outcrops of lava. A

sector collapse A sector collapse or lateral collapse is the structural failure and subsequent collapse of a minimum volume of of a volcano. Unlike smaller flank collapses, a sector collapse can involve the central volcanic pipe and historically this term had b ...

and its landslide deposit are located on Apacheta's eastern flank. Two

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

s are associated with the volcanic complex, Chac-Inca and Pabellón. The volcanic complex was active from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

to the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, but ongoing

fumarolic A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

activity has been observed and a

geothermal Geothermal is related to energy and may refer to: * Geothermal energy, useful energy generated and stored in the Earth * Geothermal activity, the range of natural phenomena at or near the surface, associated with release of the Earth's internal he ...

system is present. A

geothermal power Geothermal power is electricity generation, electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation i ...

plant was being built in 2015 and became active in late 2017, with another unit coming into service in 2022. It is the first geothermal power plant in Chile.

Geography and geomorphology

The Apacheta-Aguilucho volcanic complex lies in northern Chile, close to the border with

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

. The city of Calama lies - southwest of Apacheta-Aguilucho and

El Tatio El Tatio is a geothermal field with many geysers located in the Andes Mountains of northern Chile at above mean sea level. It is the third-largest geyser field in the world and the largest in the Southern Hemisphere. Various meanings have bee ...

is about south-southwest, but with the exception of geothermal power and

mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

-associated infrastructure the area is remote and uninhabited. Presently, the region has an

arid Aridity is the condition of geographical regions which make up approximately 43% of total global available land area, characterized by low annual precipitation, increased temperatures, and limited water availability.Perez-Aguilar, L. Y., Plata ...

climate. Vegetation, if present, consists mainly of grasses and shrubs. The volcanic complex is part of the

Central Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South Americ ...

of the Andes. The Central Volcanic Zone further includes the Altiplano-Puna volcanic complex, which between 10 and 1 million years ago was the source of large

ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...

eruptions that produced over of rock; after that it produced lava flows and lava domes like

Cerro Chao Cerro Chao is a lava flow complex associated with the Cerro del León volcano in the Andes. It is the largest known Quaternary silicic volcano body and part of the most recent phase of activity in the Altiplano–Puna volcanic complex. Cerro Ch ...

and geothermal fields such as

and

Sol de Mañana Sol or SOL may refer to: Astronomy * The Sun * Mars sol, solar day on Mars * Solar System Currency * SOL Project, a currency project in France * French sol, or sou * Argentine sol * Bolivian sol, the currency of Bolivia from 1827 to 1864 * Pe ...

, accompanied by a decreased production of volcanic material. The Altiplano-Puna volcanic complex is underpinned by a

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

tic body that appears to be a

batholith A batholith () is a large mass of intrusive rock, intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate ...

, the Altiplano-Puna Magmatic Body. Volcanic activity is the consequence of the

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

of the

Nazca Plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

beneath the

South America Plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid- ...

. Aside from volcanic activity, crustal shortening has resulted in a thickened crust since about 35 million years ago.

The volcanic complex

Apacheta-Aguilucho is a volcanic complex formed by two volcanoes, Cerro Apacheta and Cerro Aguilucho, both

composite volcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a ...

es; with the highest summit of the complex reaching a height of . The northern Aguilucho volcano and the southern Apacheta volcano are in their central portions formed by

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...

s, with the surrounding edifice formed by

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

lavas. An andesitic

lahar A lahar (, from ) is a violent type of mudflow or debris flow composed of a slurry of Pyroclastic rock, pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a valley, river valley. Lahars are o ...

and

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

crops out south and east of Apacheta, which as the oldest part of the edifice is heavily eroded. North and east of the complex, the two

s Chac-Inca and Cerro Pabellón (also known as Apacheta or Pabellóncito) form the youngest part of the volcanic complex.

Moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...

s are encountered both west-southwest of Apacheta and east of the Chac-Inca dome, and traces of glacial erosion are observed on the Aguilucho crater region. The moraines developed during the

last glacial maximum The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent between 26,000 and 20,000 years ago. Ice sheets covered m ...

Geothermal manifestations

Apacheta volcano is fumarolically active on its northern and eastern slopes as well as on the summit. Two fumaroles on the summit of Apacheta produce

superheated steam Superheated steam is steam at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured. Superheated steam can therefore cool (lose internal energy) by some amount, resulting in a lowering of its ...

at a high output; the gas has a composition typical of geothermal system fumaroles, with some differences. They are located within a wider area that features diffuse degassing,

gryphon The griffin, griffon, or gryphon (; Classical Latin: ''gryps'' or ''grypus''; Late and Medieval Latin: ''gryphes'', ''grypho'' etc.; Old French: ''griffon'') is a -4; we might wonder whether there's a point at which it's appropriate to talk o ...

mud pool A mudpot, or mud pool, is a type of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud, as a result of the acid and microorganisms decomposing surrounding rock into clay and mud. Description ...

s and vents. Apacheta-Aguilucho has a geothermal system and the chemistry of fumarole gases suggests that Apacheta-Aguilucho features an active

system at depth. Drilling has found temperatures of over at depth. This fumarolic activity has resulted in

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

alteration of many parts of the volcanic complex; this activity has generated a

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

deposit on the west flank of Aguilucho. The

mine Mine, mines, miners or mining may refer to: Extraction or digging *Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun M ...

Mina Aguilucho is located on Aguilucho's western flank. The Pabellón geothermal system was discovered in 1999, extends over an area of and is classified as a "blind" geothermal system owing to its scarce activity at the surface. The only exceptions are the fumaroles of Aguilucho and a warm spring from the power plant site; the ascent of gases to these fumaroles is presumably facilitated by the presence of intersecting faults. Thick

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

layers encountered between about and depth in drill holes presumably seal the geothermal system and block ascent to the surface. The water remains in the system for a long time and undergoes prolonged interaction with the country rock. The source of heat is unclear; the last eruptions of Apacheta-Aguilucho are too long ago and the more recent lava domes are unlikely to be associated with significant heat reserves. Another geothermal area is found in the Cordón de Inacaliri range southeast from Apacheta-Aguilucho.

Sector collapse

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

deposit extends away from the volcanic complex on its eastern flank. The landslide deposit covers a surface of about , and a large collapse scar with signs of hydrothermal alteration faces the western end of the landslide. In its upper part, the deposit is bordered to the north and south by levees. Downslope, the deposit consists at first of a lobate structure that east of the Pabellón dome grades into a more hummocky deposit. The deposit is increasingly dominated by hydrothermally altered material farther east, while the hummocks consist of lava blocks. The material of the landslide deposit itself features both solid blocks and a finer

matrix Matrix (: matrices or matrixes) or MATRIX may refer to: Science and mathematics * Matrix (mathematics), a rectangular array of numbers, symbols or expressions * Matrix (logic), part of a formula in prenex normal form * Matrix (biology), the m ...

. Rocks involved in the landslide include both

and

lavas and hydrothermally altered material. The landslide deposit is confined between two older lava flows. Sector collapses like the one at the Apacheta-Aguilucho volcanic complex have been observed on other volcanoes (such as Mount St Helens during its 1980 eruption), and they result in characteristic landslide deposits known as debris avalanche deposits; these feature hummock-like hills and often levees. Such collapses occur for different reasons for each event and are fairly common; in the Central Andes alone 14 volcanoes feature deposits of such collapses. Such deposits commonly feature a stratigraphy that resembles that of the source edifice, as well as jigsaw-like cracks in rocks that form when rocks disintegrate during the collapse and sliding. In the case of Apacheta-Aguilucho, it is likely that the sector collapse was triggered by hydrothermal alteration of the edifice that weakened its structure until it failed, and its path was likely influenced by regional tectonics. After the edifice had failed, the landslide moved eastward until it was deflected by older topography; the material became increasingly fragmented.

Geology

Off the west coast of South America, the

subducts beneath the

in the Peru-Chile Trench. This subduction process is responsible for volcanism in the Central Andes, which occurs at distances of from the trench. There are about 200 volcanoes, including a dozen giant

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

s. Two major fault systems are found close to Apacheta-Aguilucho. The first is the major regional Calama-Olacapato-El Toro fault, the second fault system runs from neighbouring Inacaliri volcano northwest of Apacheta-Aguilucho towards the southeast, where it forms the Pabellóncito

graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

; the volcanic complex is built within that graben and the eruption of Pabellón was influenced by the graben faults, which allowed magma to reach the surface. The Pabellóncito fault system was active during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Cerro del Azufre which form a northwest–southeast alignment known as Inacaliri lineament. The

basement A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...

beneath Apacheta-Aguilucho is of

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

age. It consists of various volcanic and sedimentary formations including eroded volcanoes, and it is in part covered by 7.5 million years old

Composition

Apacheta-Aguilucho has principally erupted

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

and

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

which define a

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

-rich

calc-alkaline The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic ...

suite. These rocks define a

-rich

suite which contains

amphibole Amphibole ( ) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...

biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron- endmember annite, and the magnesium-endmember phlogopite; more al ...

clinopyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron (Fe ...

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

oxide An oxide () is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of −2) of oxygen, an O2− ion with oxygen in the oxidation st ...

orthopyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron (Fe( ...

olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...

plagioclase Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

sanidine Sanidine is the high temperature form of potassium feldspar with a general formula K(AlSi3O8). Sanidine is found most typically in felsic volcanic rocks such as obsidian, rhyolite and trachyte. Sanidine crystallizes in the monoclinic crystal sys ...

and

titanite Titanite, or sphene (), is a calcium titanium nesosilicate mineral, Ca Ti Si O5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly rep ...

. Olivine is often altered to

goethite Goethite (, ) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α- polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient t ...

and

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

and there are areas of

ly altered rocks on the eastern flank and in the summit fumarole field. At the fumarole field, minerals like

chlorite The chlorite ion, or chlorine dioxide anion, is the halite (oxyanion), halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as s ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...

halloysite Halloysite is an aluminosilicate clay mineral with the empirical formula Al2Si2O5(OH)4. Its main constituents are oxygen (55.78%), silicon (21.76%), aluminium (20.90%), and hydrogen (1.56%). It is a member of the kaolinite group. Halloysite typic ...

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...

and

formed through

supergene A supergene is a chromosomal region encompassing multiple neighboring genes that are inherited together because of close genetic linkage, i.e. much less recombination than would normally be expected. This mode of inheritance can be due to genomic ...

and acid leaching processes. The magmas appear to derive from the Altiplano-Puna magmatic complex volcanic body and underwent

fractional crystallization Fractional crystallization may refer to: * Fractional crystallization (chemistry), a process to separate different solutes from a solution * Fractional crystallization (geology) Fractional crystallization, or crystal fractionation, is one of the ...

and other geochemical processes before erupting.

Eruption history

The volcanic complex is of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

age and developed over several different stages. In the first stage, the so-called Aguilucho ignimbrite consisting of moderately welded, white-to-pink

s was emplaced 7.5 ± 0.6 million years ago and andesitic lava flows 6.7 ± 0.3 million years ago. Subsequently, more lava flows were emplaced, consisting of blocky

. The Apacheta and Aguilucho volcanoes were constructed consecutively. Apacheta consists of lava flows and pyroclastic material made out of andesite, and its crater is covered by pyroclastic flows and a long rhyolitic lava flow. Aguilucho is constructed by lava flows. Finally, several lava flow fields were emplaced together with the lava domes Pabellón and Chac-Inca. 1,204,000 ± 33,000 years ago an

named Aguilucho ignimbrite was erupted from the Apacheta volcano. Apacheta grew between about 1.024 and 0.9 million years ago and Aguilucho between 0.7 and 0.6 million years ago.

Lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

s on Apacheta-Aguilucho have been dated to 910,000 ± 140,000 and 700,000 ± 200,000 years before present, with one lava flow being dated to 652,000 ± 12,000 years ago. The date of the sector collapse is not known with certainty but was probably after the last lava flow was emplaced on Apacheta-Aguilucho. Dating of Chac-Inca has produced an age of 140,000 ± 80,000 years before present. Different dates have been obtained on Cerro Pabellón: Potassium-argon dating yields an age of 130,000 - 80,000 years before present, while argon-argon dating has yielded an age of 50,000 ± 10,000 years before present. Their emplacement was presumably triggered by the entry of new magma into the magmatic system, and their ascent facilitated by the faults in the area. After the cessation of volcanic activity at Apacheta-Aguilucho, it appears to have migrated to the neighbouring Azufre volcano. Future eruptions may consist of small explosions with local impact, of perhaps

phreatic ''Phreatic'' is a term used in hydrology to refer to aquifers, in speleology to refer to cave passages, and in volcanology to refer to a type of volcanic eruption. Hydrology The term phreatic (the word originates from the Greek , meaning "well" ...

nature. A local subsidence of the ground began in 2017 and ended in 2020 appears to be related to the beginning geothermal power extraction.

Geothermal power production

The discovery of steam during the drilling of a freshwater well in the 1990s led to investigations by ENAP and

UNOCAL Union Oil Company of California, and its holding company Unocal Corporation, together known as Unocal was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headqu ...

in the area and the discovery of the fumaroles. In 2002, a joint enterprise by ENAP and

CODELCO The National Copper Corporation of Chile (), abbreviated as Codelco, is a Chilean state-owned mining company and the largest copper mining company in the world. It was formed in 1976 from foreign-owned copper companies that were nationalised in 1 ...

obtained the permission to explore the area, but while a geothermal system was discovered political questions about ENAP's involvement derailed the project. Another joint enterprise this time including the Italian

ENEL Enel S.p.A. is an Italian multinational manufacturer and distributor of electricity and gas. Enel was first established as a public body at the end of 1962, and then transformed into a limited company in 1992. In 1999, following the liberali ...

performed further research in the area between 2006 and 2007, and obtained a permit to exploit the system in 2009. The joint enterprise started the

project Cerro Pabellón, and in 2015 the construction of two power plants with a projected output of 24 MW each started, to be completed in 2017–2018. The plant on Pampa Apacheta east of Apacheta-Aguilucho was inaugurated by the Chilean president

Michelle Bachelet Verónica Michelle Bachelet Jeria (; born 29 September 1951) is a Chilean politician who served as President of Chile from 2006 to 2010 and again from 2014 to 2018, becoming the first woman to hold the presidency. She was re-elected in December ...

on 12 September 2017, becoming the first geothermal power station in South America, and drew substantial media attention. , it is the only operating one. Situated at an elevation of over , it is the highest large-scale geothermal plant in the world. It draws water and steam from eight production wells, which are used to boil

isopentane Isopentane, also called methylbutane or 2-methylbutane, is a branched-chain saturated hydrocarbon (an alkane) with five carbon atoms, with formula or . Isopentane is a volatile and flammable liquid. It is one of three structural isomers with t ...

that then powers turbines; the condensate is reinjected into wells. The Cerro Pabellón project is expected to produce 340

Gigawatt-hours A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a non-SI unit of energy equal to 3.6 megajoules (MJ) in SI units, which is the energy delivered by one kilowatt of power for one hour. Kilowatt-hours are a common b ...

per year, enough to cover the electricity consumption of 165,000 families. The plant is expected to reduce Chile's

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

emissions by about and is owned by the companies Geotérmica del Norte S.A.(GDN) and Empresa Nacional de Geotermia; the latter is a

joint venture A joint venture (JV) is a business entity created by two or more parties, generally characterized by shared ownership, shared returns and risks, and shared governance. Companies typically pursue joint ventures for one of four reasons: to acce ...

between ENAP and ENEL. A further expansion began in 2019 and was completed in 2022, aiming at increasing output by about 33 MW to 81 MW. The plant uses

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

for energy storage.

Notes

References

Sources

* * * * * * * * * * * * * *

External links

* * {{cite report, url=http://seia.sea.gob.cl/expediente/ficha/fichaPrincipal.php?modo=ficha&id_expediente=5569783, language=es, ref=none, publisher=SGA, author=Cristian Andrés Gutiérrez Villalobos, series=Forma de Presentación: Estudio de Impacto Ambiental, title=Ficha del Proyecto: Central Geotérmica Cerro Pabellón Stratovolcanoes of Chile Dormant volcanoes Pleistocene stratovolcanoes Geothermal energy in Chile