Guallatiri is a

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

with an elevation of . It is located southwest of the Nevados de Quimsachata volcanic group; some sources classify Guallatiri as a member. Guallatiri is a

stratovolcano 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 ...

with numerous

fumarole 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 ...

s around the summit. The summit may be a

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 ...

volcanic plug A volcanic plug, also called a volcanic neck or lava neck, is a volcano, volcanic object created when magma hardens within a Volcanic vent, vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if risi ...

, while the lower flanks of the volcano are covered by

lava flows Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or unde ...

and lava domes. The volcano's eruptions have produced mostly

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. ...

along with

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 ...

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 ...

. Past

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

has left

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 on Guallatiri. A large eruption took place approximately 2,600 years ago. Guallatiri has been

active Active may refer to: Music * ''Active'' (album), a 1992 album by Casiopea * "Active" (song), a 2024 song by Asake and Travis Scott from Asake's album ''Lungu Boy'' * Active Records, a record label Ships * ''Active'' (ship), several com ...

in historical times with a number of eruptions, the latest in 1960. Fumarolic and seismic activity is ongoing and has resulted in the deposition of

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 ...

and other minerals on the volcano. The volcano is covered by an

ice cap In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses covering more than are termed ice sheets. Description By definition, ice caps are not constrained by topogra ...

above that has shrunk and fragmented during the course of the 20th and 21st centuries. Guallatiri, along with several other volcanoes, is part of Lauca National Park and is monitored by the Chilean National Geology and Mining Service (SERNAGEOMIN).

Name and ascents

The term Guallatiri is derived from , which means in Aymara, referring to the birds' frequent occurrence in the area. Other names are (also an Aymara word), Huallatiri, Huallatire and Guallatire. It was first climbed in 1926 by the geologist . The volcano is considered to be easy to ascend (rated F on the French Climb grading by John Biggar) but toxic gases constitute a hazard in the summit region.

Geography and geomorphology

The volcano lies in the

Putre Putre is a Chilean town and commune, capital of the Parinacota Province in the Arica-Parinacota Region. It is located east of Arica, at an altitude of . The town is backdropped by Taapaca volcanic complex. Putre is on the edge of the Lauc ...

municipality A municipality is usually a single administrative division having municipal corporation, corporate status and powers of self-government or jurisdiction as granted by national and regional laws to which it is subordinate. The term ''municipality' ...

Arica y Parinacota Region The Arica y Parinacota Region ( ) is one of Chile's 16 first order administrative divisions. It comprises two provinces, Arica Province, Arica and Parinacota Province, Parinacota. It borders Peru's Department of Tacna to the north, Bolivia's La ...

. It is located south of Lake Chungará and west of Cerro Capurata. The latter is part of the Nevados de Quimsachata volcano chain which includes Umurata, Acotango and Capurata; sometimes Guallatiri is considered to be part of the Nevados de Quimsachata. The older Umurata and Acotango volcanoes are heavily eroded; Capurata is better preserved. Guallatiri is part of the larger Western Cordillera, the western boundary of the

Altiplano The Altiplano (Spanish language, Spanish for "high plain"), Collao (Quechuan languages, Quechua and Aymara language, Aymara: Qullaw, meaning "place of the Qulla people, Qulla") or Andean Plateau, in west-central South America, is the most extens ...

high plateau. The small town of Guallatiri is southwest of the volcano and is the settlement closest to it; the town has a 17th-century church and a refuge of the National Forest Corporation. Other nearby towns include Ancuta, Carbonire and Churiguaya. each had a population of less than 25 people. The provincial capital

is north of the volcano, and farther west, on the Pacific coast, is

Arica Arica ( ; ) is a commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the ca ...

. Economic activity in the area includes the Tambo Quemado

border crossing Border control comprises measures taken by governments to monitor and regulate the movement of people, animals, and goods across land, air, and maritime borders. While border control is typically associated with international borders, it als ...

, agriculture, animal husbandry, tourism and mountaineering, including ascents to the summit of Guallatiri. There are no known archeological sites on the summit of Guallatiri, unlike several other mountains in the region. Possible reasons are the continuous ice cover and the constant volcanic activity. The frontier between Bolivia and Chile runs along the Nevados de Quimsachata northeast of Guallatiri, not far from the volcano. The volcano is remote and thus poorly known.

The volcano

Guallatiri is or high; claims of even higher elevations appeared in past and some recent publications. It is a

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 ...

with a symmetric cone surmounted by a

, lava complex or

and a vent just south of it. Lava domes, lava flows,

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

and

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

make up the mountain. Guallatiri rises about above the surrounding terrain and covers an area of about ; the total volume is about . Thick lava flows emanate in all directions but are primarily noted on the northern and western flanks. The flows reach thicknesses of and lengths of . The lava flows have a lobate appearance even when they are heavily eroded, and display

levees A levee ( or ), dike (American English), dyke (British English; see spelling differences), embankment, floodbank, or stop bank is an elevated ridge, natural or artificial, alongside the banks of a river, often intended to protect against fl ...

, ogives, polygonal cracks and blocky surfaces. Older flows have been eroded into hills. Block-and-ash flows form fans on the southern and southwestern flanks. Tephra deposits are mainly located on the eastern and southern side of Guallatiri.

Tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

s 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 ...

deposits occur both in the summit region and in radial valleys that emanate from Guallatiri, although some of the deposits southwest of the volcano have been reinterpreted as being reworked sediments. Apart from volcanic rocks,

glacial deposit image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

s cover large parts of the volcano, and there are traces of mass failures. On the southern flank, there are two

s named Domo Tinto and Domo Sur; other than these Guallatiri has no lateral vents. Domo Tinto is wide and high while Domo Sur ( southwest of Domo Tinto) is thick and wide. Domo Tinto has a hummocky surface and resembles a pancake. There are both cold springs and

hot spring A hot spring, hydrothermal spring, or geothermal spring is a Spring (hydrology), spring produced by the emergence of Geothermal activity, geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow ...

s on Guallatiri, indicating that

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

interacts with the magmatic system. One hot spring is located at Chiriguaya on the northwestern foot of Guallatiri, where temperatures of were measured in bubbling pools, and sinter deposition takes place. Several

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

s run off the mountain; they eventually enter Lake Chungará and the

Lauca River The Lauca River is a binational river. It originates in the Chilean Altiplano of the Arica and Parinacota Region, crosses the Andes and empties into Coipasa Lake in Bolivia. The upper reach of the river lies within the boundaries of Lauca Na ...

Ice

Above – elevation the volcano is covered with ice in the form of

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

s. , an

on Guallatiri covered an area of and had a volume of . Ice area has been retreating at a rate of (between 1988 and 2017), leading to the breakup of the ice cap into several separate ice bodies. According to a 2005 study by Rivera ''et al.'', heat emitted by

s may have contributed to the enhanced melting of the ice. Glacial deposits on Guallatiri cover an area of about above elevation, with lateral moraines reaching lengths of and thicknesses of . Glaciers reached their maximum extent between 13,500 and 8,900 years ago. This is unlike the global

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 ...

(LGM), which peaked between 21,000 and 19,000 years ago. This is a consequence of the climate in the region, where glacier extent was more sensitive to increased moisture supply than to decreasing temperatures; presumably the global LGM was too dry to allow glacier formation. Some glaciers were still present during the Holocene, evidenced by Holocene-age Domo Tinto lava dome which bears traces of glacial erosion and is partially covered by moraines. Volcanic units are found both overlying and underlying glacial deposits such as

s. Older volcanic rocks bear

glacial striation Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them ...

s, and

volcanic bomb A volcanic bomb or lava bomb is a mass of partially molten rock (tephra) larger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. Because volcanic bombs cool after they l ...

s on the lower flanks may have been transported there by glaciers.

Geology

Off the western coast of South America, 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– ...

subducts beneath the

South American 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 ...

at a rate of about . The subduction process is responsible for the volcanism of the

Northern 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 America ...

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 ...

(CVZ) and

Southern 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 America ...

, and has also driven the formation of the Altiplano during the last 25 million years. The CVZ is a long chain of volcanoes spanning southern Peru, northern Chile, western Bolivia and northwestern Argentina. It contains about 58 active or potentially active volcanoes, 33 of which are located within Chile. The most active CVZ volcano is

Lascar A lascar was a sailor or militiaman from the Indian subcontinent, Southeast Asia, the Arab world, British Somaliland or other lands east of the Cape of Good Hope who was employed on European ships from the 16th century until the mid-20th centur ...

, which in 1993 produced the largest historical eruption of northern Chile. Guallatiri rises above

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Formations. The Lupica Formation is older and consists mainly of volcanic rocks, while the Lauca Formation is formed by volcanic and sedimentary rocks that were deposited within the basin and in part altered by glaciers.

Archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

rocks make up 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, ...

. There is evidence that the terrain was tectonically active during the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

Composition

The composition of Guallatiri's rocks ranges from

over

, with dacites being predominant. The summit dome is formed by

and most outcrops are trachyandesite and trachydacite. The rocks 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 and contain

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 ...

apatite Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of Hydroxide, OH−, Fluoride, F− and Chloride, Cl− ion, respectively, in the crystal. The formula of the admixture of ...

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 ...

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 ...

and

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 ...

phenocryst image:montblanc granite phenocrysts.JPG, 300px, Granites often have large feldspar, feldspathic phenocrysts. This granite, from the Switzerland, Swiss side of the Mont Blanc massif, has large white phenocrysts of plagioclase (that have trapezoid sh ...

s, similar to other volcanoes in the region. A single lava bomb made out of

obsidian Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter element ...

has been found.

Mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

rock enclaves have been observed in Domo Tinto rocks, which indicate that mafic magmas were injected into the

magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it u ...

and mixed with already present magma. Fractional crystallization and magma mixing processes gave rise to Guallatiri's magmas. Fumaroles have deposited minerals such as

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...

baryte Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate (Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

cristobalite Cristobalite ( ) is a mineral polymorph of silica that is formed at very high temperatures. It has the same chemical formula as quartz, Si O2, but a distinct crystal structure. Both quartz and cristobalite are polymorphs with all the members o ...

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 ...

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 ...

sassolite Sassolite is a borate mineral, specifically the mineral form of boric acid. It is usually white to gray, and colourless in transmitted light. It can also take on a yellow colour from sulfur impurities, or brown from iron oxides. History and occ ...

and

. Less common are

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

orpiment Orpiment, also known as ″yellow arsenic blende″ is a deep-colored, orange-yellow arsenic sulfide mineral with formula . It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and may be formed through sublimatio ...

and

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

. Sulfur deposits have yellow, orange or red colours and are sometimes accompanied by

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

-sulfur compounds that also contain

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

, mercury,

selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...

and

tellurium Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...

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 ...

deposits occur on Guallatiri's southern flank; according to the first Panamerican Congress on Mine Engineering and Geology, in 1942 the volcano had about of sulfur

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...

with a grade of about 55% sulfur. The volcano may be an important cause of arsenic pollution in the region.

Flora, fauna and climate

The volcano is inside the Lauca National Park and the

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

s () in the area of Guallatiri have regional importance. Vegetation there include '' Arenaria rivularis'', '' Calandrinia compacta'', '' Deyeuxia curvula'', '' Distichlis humilis'', '' Lobelia oligophylla'' and '' Oxychloe andina''. Animal species include birds such as the Andean flamingo,

Andean gull The Andean gull (''Chroicocephalus serranus'') is a species in subfamily Larinae of the family Laridae, the gulls, terns, and skimmers. It is found in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru.Remsen, J. V., Jr., J. I. Areta, E. ...

, Andean goose, buff-winged cinclodes,

Chilean flamingo The Chilean flamingo (''Phoenicopterus chilensis'') is a species of large flamingo at a height of closely related to the American flamingo and the greater flamingo, with which it was previously considered a subspecies before being classified ...

condor Condor is the common name for two species of New World vultures, each in a monotypic genus. The name derives from the Quechua language, Quechua ''kuntur''. They are the largest flying land birds in the Western Hemisphere. One species, the And ...

, giant coot,

James's flamingo James's flamingo (''Phoenicoparrus jamesi''), also known as the puna flamingo, is a species of flamingo that lives at high altitudes in the Andes, Andean plateaus of Peru, Chile, Bolivia, and northwest Argentina. It is named for Harry Berkeley Ja ...

, mountain parakeet, Puna ibis, Puna tinamou and torrent duck. Among the mammals are the

alpaca The alpaca (''Lama pacos'') is a species of South American camelid mammal. Traditionally, alpacas were kept in herds that grazed on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile. More recentl ...

, Altiplano chinchilla mouse, Andean swamp rat, lesser grison,

llama The llama (; or ) (''Lama glama'') is a domesticated South American camelid, widely used as a List of meat animals, meat and pack animal by Inca empire, Andean cultures since the pre-Columbian era. Llamas are social animals and live with ...

, mountain degu, Osgood's leaf-eared mouse,

short-tailed chinchilla The short-tailed chinchilla (''Chinchilla chinchilla)'' is a small rodent part of the Chinchillidae family and is classified as an endangered species by the IUCN. Originating in South America, the chinchilla is part of the genus ''Chinchilla'', w ...

and

vicuña The vicuña (''Lama vicugna'') or vicuna (both , very rarely spelled ''vicugna'', Vicugna, its former genus name) is one of the two wild South American camelids, which live in the high alpine tundra, alpine areas of the Andes; the other cameli ...

Woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...

s formed by the tree '' Polylepis tarapacana'' occur on Guallatiri; this tree forms the world's highest woodlands. The upper parts of the mountain are covered with rocks and pioneer vegetation to about elevation. The region has a

tundra climate The tundra climate is a polar climate sub-type located in high latitudes and high mountains. It is classified as ET according to the Köppen climate classification. It is a climate which at least one month has an average temperature high enough ...

. Most precipitation falls during the summer months, amounting to about per year, averaged between 1997 and 2017. Moisture mainly originates in the Atlantic Ocean and the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

, especially during cold events of the

El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variation in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cyc ...

when moisture supply increases.

Tree ring Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in a tree. As well as dating them, this can give data for dendroclimatology, the study of climate ...

chronologies from '' Polylepis tarapacana'' trees growing at Guallatiri have been used for climate reconstructions.

Eruptive history

Volcanic activity at Guallatiri commenced either about 710,000 or 262,000–130,000 years ago and the volcano subsequently grew during 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 ...

and

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

. Total magma supply at Guallatiri amounts to , less than at

Parinacota Parinacota (in Hispanicized spelling), Parina Quta or Parinaquta ( Aymara, ''parina'' flamingo, ''quta'' lake, "flamingo lake", other Hispanicized spellings ''Parinaccota, Parinajota'') may refer to: Lakes * Parinaquta (Carabaya), in Peru, Puno ...

but greater than at Lascar. Jorquera et al. in 2019 described a two-stage growth of the volcano. Initially, the "Guallatiri I" stage grew in the form of andesitic and dacitic lava flows as well as heavily eroded pyroclastic deposits, which crop out around the volcano. Then the dacitic "Guallatiri II" developed in close proximity to the central vent; unlike the "Guallatiri I"

units Unit may refer to: General measurement * Unit of measurement, a definite magnitude of a physical quantity, defined and adopted by convention or by law **International System of Units (SI), modern form of the metric system **English units, histo ...

it has not been eroded by glaciation and flows still display flow structures. The central sector of the volcano is mainly of Holocene age while the peripheral parts date to the Pleistocene. In 2021, Sepúlveda et al. envisaged six separate stages, rocks from the first four crop out mainly at the periphery of the volcano and the last two in its central sector. All these units were erupted by the central vent of Guallatiri. Some lava flows are well preserved, while others have been glaciated. Large eruptions similar to the 1993 eruption of Lascar may have occurred at Guallatiri. The largest Holocene event at the volcano was a

Plinian Plinian eruptions or Vesuvian eruptions are volcanic eruptions characterized by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a le ...

or sub-Plinian eruption that deposited tephra and pumice southwest of the volcano, reaching thicknesses of at distance, approximately 2,600 years ago. Non-explosive eruptions also took place, such as the Domo Tinto eruption 5,000 ± 3,000 years ago. The eruption emplaced lobes of lava over a flat surface.

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 ...

deposits extend from Guallatiri.

Radiocarbon dating Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotop ...

has yielded ages ranging between 6,255 ± 41 and 140 ± 30 years

Before Present Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because ...

. These flows are unrelated to the lava domes, which show no evidence of collapses that could have formed pyroclastic flows.

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 ...

deposits are found on the southern flanks of the volcano and do not exceed thickness. They form when volcanic material interacts with water, produced either by the melting of ice or through intense rainfall. Traces of Holocene-age lahars from Guallatiri have been found in river valleys.

Historical and seismic activity

Guallatiri is the second-most active volcano (after

) in northern Chile. Since the 19th century, numerous small

explosive eruption In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a Viscosity, viscous ...

s have produced thin

layers. The eruption history of Guallatiri is little known and historical eruptions are poorly documented. Eruptions with a

volcanic explosivity index The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption c ...

of 2 took place in 1825 ± 25, 1913, July 1959, and December 1960. A further uncertain eruption took place in 1908 and additional poorly documented eruptions are reported from 1862, 1864, 1870, 1902, 1904, and 1987. Radiocarbon dating has yielded evidence of at least one eruption during the past 200 years. Increased steam emission was observed in December 1985 and initially attributed to Acotango volcano, before it was linked to Guallatiri; it may have been an eruption of the latter. In May 2015, the Chilean National Geology and Mining Service (SERNAGEOMIN) raised the volcano alert level when seismic activity increased and a high plume appeared over the volcano, only to lower it again in July when activity decreased. Shallow

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

s and sporadic seismic swarms have been recorded at Guallatiri; one such swarm was induced by the 2001 Peru earthquake. Satellite imaging has not shown any evidence of ongoing deformation of the volcanic structure.

Fumarolic activity

Guallatiri features

s and

solfatara 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 ...

s, and mud pools have also been reported. There are two main areas, one on the western flank below the summit and another on the south-southwestern flank. Fumaroles form alignments, and a long fracture lies in the southern area. Some sources also identify a third area on the upper western flank. The vents of individual fumaroles sometimes form wide and high cones, and there are small explosion craters reaching widths of in the summit region.

Pahoehoe Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or unde ...

-like flows up to long have been formed by liquid

. Other minerals deposited by the fumaroles are

sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

s such as

and

sulfide Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families o ...

s, including

cinnabar Cinnabar (; ), or cinnabarite (), also known as ''mercurblende'' is the bright scarlet to brick-red form of Mercury sulfide, mercury(II) sulfide (HgS). It is the most common source ore for refining mercury (element), elemental mercury and is t ...

antimony Antimony is a chemical element; it has chemical symbol, symbol Sb () and atomic number 51. A lustrous grey metal or metalloid, it is found in nature mainly as the sulfide mineral stibnite (). Antimony compounds have been known since ancient t ...

sulfides and

sulfides. The temperatures of the fumaroles range between . Guallatiri produces gases consisting of

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 ...

and

water vapour Water vapor, water vapour, or aqueous vapor is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Water vapor ...

, with

hydrogen chloride The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...

hydrogen fluoride Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluori ...

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

and

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

as additional components. They appear to originate from a

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 ...

system where intense rock-gas interaction takes place. The water originates in part from the magma and in part from precipitation. Different degrees of interaction with precipitation water may explain why the south-southwestern flank fumarole gases have a different composition than these released in the summit region. The fumarolic activity has produced intense

alteration of Guallatiri's rocks east-northeast of the summit and at a lower elevation northwest of it.

Fumarole plume

Fumarole clouds, derived mainly from the summit fumarole, are visible for more than and from

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

images. The fumarole cloud influences the perception of volcanic activity by the local population. Puffing behaviour was noted in 1996 and emissions every half-hour in November 1987, which gave rise to yellow-white plumes up to high. Jet-like noises are heard from the fumaroles. According to a report by mountaineers in 1966, fire emanated from the fumarole vents.

Hazards and monitoring

Future eruptions may consist of the emission of lava domes or lava flows, preceded by explosive activity that could impact the settlements of Ancuta and Guallatiri on the southern and western flanks. Large explosive eruptions could deposit pyroclastics over hundreds of kilometres, with the direction depending on the wind at the time of the eruption.

s would mainly impact the western and southwestern sectors of the volcano, as the snow cover is concentrated there.

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 would also primarily impact this sector of the volcano.

s may impact areas within of Guallatiri, including the settlements Ancuta and Guallatiri. Apart from Ancuta and Guallatiri in Chile, the volcano may threaten towns in Bolivia and ash clouds from Guallatiri could impact airports in the wider region as far as

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

and

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. The vulnerability of the local population reflects both widespread poverty and marginalization, and the low population density. Significant eruptions are expected to reoccur on century timescales. Guallatiri is in the second category in the Chilean scale of dangerous volcanoes and is the 30th most dangerous in the country. In 2013, the Southern Andean Volcano Observatory began to monitor Guallatiri by video, measurements of seismic activity and deformations of the volcanic structure. Volcano hazard maps have been published.

Mythology and religious importance

Guallatiri was considered to be an or , a protective mountain spirit. The mountain was and still is worshipped by local inhabitants, and the church in the town of Guallatiri is constructed so that it points to the volcano. In the past, the Aymara community of Guallatire used to celebrate rituals at the foothills of the volcano every January 1. They regarded Guallatiri, which they called Qapurata, to be a family consisting of a wife (the eastern María Qapurata), a husband (the western Pedro Qapurata) and a daughter (the middle Elena Qapurata). In the

oral tradition Oral tradition, or oral lore, is a form of human communication in which knowledge, art, ideas and culture are received, preserved, and transmitted orally from one generation to another.Jan Vansina, Vansina, Jan: ''Oral Tradition as History'' (19 ...

of Chipaya, cold winds called blow from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

to the

and towards Guallatiri. The volcano there is linked with

Hell In religion and folklore, hell is a location or state in the afterlife in which souls are subjected to punishment after death. Religions with a linear divine history sometimes depict hells as eternal destinations, such as Christianity and I ...

. The Chipaya believed that the waters of the

originate on Guallatiri and come directly from hell.