Volcán Tupungatito is the northernmost historically active

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

of the southern

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

. Part of the Chilean Andes' volcanic segment, it is the northernmost member of the

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 ...

(SVZ), which is one of several distinct volcanic belts in the Andes. Over 70

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

age volcanoes make up this volcanic belt, which on average has one eruption per year. Tupungatito lies in proximity to the border between

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

and

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

, 50 miles east of the Chilean capital

Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whos ...

. It is a group of

volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an und ...

s and a

pyroclastic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

associated with a wide

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

, and lies just southwest of the

Tupungato Tupungato, one of the highest mountains in the Americas, is a massive Andean lava dome dating to Pleistocene times. It lies on the border between the Chilean Metropolitan Region (near a major international highway about east of Santiago) and t ...

volcano. The caldera is filled with

ice Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaqu ...

, and

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

s on the volcano are important sources of water for the Rio Maipo river and Santiago. Volcanism is caused by the

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...

of the

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

underneath 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-A ...

. Tupungatito formed less than 100,000 years ago and has had a number of historical eruptions, the latest in 1987, which were mostly 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 viscous magma su ...

s. Presently, the volcano features an acidic

crater lake Crater Lake ( Klamath: ''Giiwas'') is a volcanic crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fill ...

and numerous

fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or other 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. Renewed eruptions could induce

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

falls in Argentina and dangerous

mudflow A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a significa ...

s in Chile.

Name and history

The name was assigned to the volcano by , the chair of the Chilean boundary commission, in 1897. It refers to the neighbouring

volcano; Luis Risopatrón also reported that Tupungatito was an active volcano. The volcano is also known as Volcan Bravard, a name proposed by Argentina but which fell into disuse; it references the French

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Auguste Bravard (Pierre Joseph) Auguste Bravard (18 June 1803 – 28 March 1861) was a French mining engineer turned palaeontologist. He hunted fossils in the Vaucluse, Allier and his native Puy de Dôme. Biography Bravard emigrated to Argentina in the winter of ...

. There was speculation about the existence of a volcano in the Andes near Santiago already during the Colonial Era, but only by 1890 was there a clear identification and even then it was frequently assumed that Tupungato instead was the only active edifice. The first ascent of the volcano probably took place in 1907, by K. Griebel, H. Gwinner, L. Hanisch, K. Heitmann and J. Philippi.

Geography and geomorphology

Tupungatito is located in the Chilean

, east from

Santiago de Chile Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, who ...

. Politically, it is part of the San Jose de Maipo municipality in the

Metropolitan Region A metropolitan area or metro is a region that consists of a densely populated urban agglomeration and its surrounding territories sharing industries, commercial areas, transport network, infrastructures and housing. A metro area usually com ...

where about 40% of all Chileans live. high,

volcano rises northeast of Tupungatito.

Tourism Tourism is travel for pleasure or business; also the theory and practice of touring (disambiguation), touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tour (disambiguation), tours. Th ...

mountaineering Mountaineering or alpinism, is a set of outdoor activities that involves ascending tall mountains. Mountaineering-related activities include traditional outdoor climbing, skiing, and traversing via ferratas. Indoor climbing, sport climbing, ...

and

hiking Hiking is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century.AMATO, JOSEPH A. "Mind over Foot: Romantic Walking and Rambling." In ''On Foot: A Histor ...

are the principal economic activities in the area; in addition, there are mines and

hydropower plant Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

s in the valleys. The volcano features a wide caldera with an erupted volume of and one or two openings to the western flank, and a group of ten craters north of the caldera. Four of these craters overlap and one is located on top of a wide

northwest of the remaining craters. Three

s are hosted within these craters; one has a turquoise colour and highly

acidic In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a ...

water. The total volume of the volcano is estimated to be , and its flows are fresh and uneroded. The caldera may either be of volcanic origin or the product of a giant

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

. In the past, lava flows have exited the caldera through the northwestern opening.

Glaciers and hydrology

Above elevation, the volcano is covered with

. On Tupungatito ice covers an area of about , which is part of a larger ice cover on regional volcanoes. The caldera contains the Tupungatito glacier, with a volume of about it is the most important glacier of the Metropolitana Region. The cold ice lacks internal water pockets and reaches a maximum thickness of .

Outlet glacier Glacier morphology, or the form a glacier takes, is influenced by temperature, precipitation, topography, and other factors. The goal of glacial morphology is to gain a better understanding of glaciated landscapes and the way they are shaped. Ty ...

s of glaciers in the region are typically covered with debris. In 2012, an

ice core An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ...

was drawn from the Tupungatito glacier. The ice and snow cover on Tupungatito is an important source of water for the rivers in the region and Santiago. Meltwater is discharged westwards into the Colorado- Maipo river system that eventually flows through Santiago; the Quebrada Seca, Estero de Tupungatito and Estero de Tupungato originate close to the volcano and are tributaries to the Colorado. Some glaciers drain instead eastward into the Rio Tupungato river, which as a tributary of the

Rio Mendoza The Mendoza River is a river in the province of Mendoza, Argentina.Mendoza in Argentina and the surrounding

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

areas.

Arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, b ...

pollution in the Maipo river system may originate from springs associated the volcanoes Tupungatito and San Jose.

Geology

Regional

Off the coast of South America, the

subduct Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

s beneath the

at a rate of . Volcanism in the Andes occurs in four separate volcanic belts, 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 ...

, 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 American ...

, the

(SVZ) and the

Austral 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 ...

. The SVZ is a long and, depending on latitude, up to wide chain of

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). It follows the Neogene Period and spans from 2.58 million year ...

volcanoes, subdivided according to two schemes in two or three sectors. It features over 70

es, as well as

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallo ...

s and

scoria cone Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ...

s. About 30-40 were active

postglacial The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

ly and 18-20 in historical times; the SVZ is the most active volcanic zone in Chile with about one eruption per year. Tupungatito is part of the northernmost SVZ, a narrow and short chain which includes Diamante caldera/ Volcan Maipo and San Jose volcano, and is the northernmost active volcano of the SVZ. Tupungato-Tupungatito, San Jose-

Marmolejo Volcán Marmolejo is a high Pleistocene stratovolcano in the Andes on the border between Argentina and Chile. It is located NNE of the active San José volcano, and is the southernmost -plus peak in the world. The Argentine portion is withi ...

and Maipo are the highest volcanoes of the SVZ.

Local

The volcano lies on a thick crust, which together with the tectonic regime has influenced the composition of ascending magma. The

basement A basement or cellar is one or more Storey, floors of a building that are completely or partly below the storey, ground floor. It generally is used as a utility space for a building, where such items as the Furnace (house heating), furnace, ...

underneath Tupungatito consists of

evaporite An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean ...

s and marine

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...

s of

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

age. Cretaceous

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** ...

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

s and

volcaniclastic Volcaniclastics are geologic materials composed of broken fragments ( clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it ...

rocks, as well as

Miocene The Miocene ( ) is the first 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 means "less recen ...

sediments. The

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

rocks have been deformed during regional tectonic activity and there are numerous

reverse fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectoni ...

s in the area. Southwest-northeast and north-south trending faults and fractures influence volcanic activity at Tupungatito; the SW-NE trending lineament also includes Tupungato. The volcano forms a

volcanic group A volcanic group is a stratigraphic group consisting of volcanic strata. They can be in the form of volcanic fields, volcanic complexes and cone A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequ ...

with Tupungato and another peak, high Nevado Sin Nombre. Tupungato and Nevado Sin Nombre formed during the late and early

, respectively, and are presently inactive. The caldera is to a large degree formed by rocks from Nevado Sin Nombre. high

Nevado de los Piuquenes Nevado (1813? – 1821) was a Mucuchies dog that was given to Simón Bolívar by the local people of Mucuchíes, Mérida, in the Venezuelan Andes. It was given as a kind of present shortly after the Battle of Niquitao during his triumphal A ...

is a fourth volcano in this group and overlaps with Nevado Sin Nombre. Below elevation, Tupungatito is underlaid by an eroded volcano whose rocks resemble Tupungato.

Composition

Tupungatito has erupted rocks ranging from

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Am ...

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 rhyo ...

, which define a

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmos ...

-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 m ...

suite. There has been little compositional variation during its history.

Phenocryst 300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter ...

s include

clinopyroxene The pyroxenes (commonly abbreviated to ''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 calcium (Ca), sodium (Na), iron (Fe I ...

and

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more p ...

and less commonly

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers qui ...

and

orthopyroxene The pyroxenes (commonly abbreviated to ''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 calcium (Ca), sodium (Na), iron (Fe I ...

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 ...

and

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 ...

occur as

xenocryst A xenolith ("foreign rock") is a rock fragment (country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusively used to describe inclusions in ig ...

s. Magma genesis at Tupungatito and other volcanoes in the region appears to involve a small amount of fluids but large amounts of sediments carried down by the

slab Slab or SLAB may refer to: Physical materials * Concrete slab, a flat concrete plate used in construction * Stone slab, a flat stone used in construction * Slab (casting), a length of metal * Slab (geology), that portion of a tectonic plate tha ...

, with a moderate interaction with the crust. Processes involved are fractional crystallization, low degrees of

partial melting Partial melting occurs when only a portion of a solid is melted. For mixed substances, such as a rock containing several different minerals or a mineral that displays solid solution, this melt can be different from the bulk composition of the soli ...

and short periods of storage in

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 up ...

Climate

The mean annual temperature on Tupungatito is about and annual

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughou ...

accumulation is about

snow water equivalent Snow science addresses how snow forms, its distribution, and processes affecting how snowpacks change over time. Scientists improve storm forecasting, study global snow cover and its effect on climate, glaciers, and water supplies around the worl ...

. During the winter, the area above elevation is covered with up to of snow. Most precipitation occurs between May and September, when the north-south movement of the

South Pacific High The South Pacific High is a semi-permanent subtropical anticyclone located in the southeast Pacific Ocean. The area of high atmospheric pressure and the presence of the Humboldt Current in the underlying ocean make the west coast of Peru and n ...

and the

Westerlies The westerlies, anti-trades, or prevailing westerlies, are prevailing winds from the west toward the east in the middle latitudes between 30 and 60 degrees latitude. They originate from the high-pressure areas in the horse latitudes and tren ...

lets

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ...

systems reach the area. Glaciers have alternatively advanced and retreated during the 20th century. There is some uncertainty as sometimes snow cover is confused for glacial ice. ice covers an area of , down from in 1986; this encompasses the ice cover of Tupungatito and other volcanoes in the area. Volcanic eruptions have not significantly altered the ice extent.

Eruption history

Tupungatito is about 55,000 or less than 80,000 years old. Early activity was

effusive In physics and chemistry, effusion is the process in which a gas escapes from a container through a hole of diameter considerably smaller than the mean free path of the molecules. Such a hole is often described as a ''pinhole'' and the escape ...

, producing

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 moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s up to long as well as

debris flow Debris flows are geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. They generally ...

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

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 ...

s which invaded the Rio Colorado valley. Two sequences of volcanic rocks crop out in the valley and its tributaries, both with thicknesses of about . They have been dated to 52,000±23,000 and 31,000±10,000 years ago, respectively. About 30,000 years ago, a change to a more effusive style of volcanic activity took place with shorter lava flows, although with shorter lava flows. Numerous debris avalanches took place on Tupungatito and left deposits in the western valleys. Tupungatito may be the source of late

rhyolite 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 ...

deposits around the city of Mendoza and Pleistocene

tephra Tephra is fragmental material produced by a 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, they r ...

overlying

glacial 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 betwe ...

deposits in the

Rio Mendoza The Mendoza River is a river in the province of Mendoza, Argentina.Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

activity added an

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

component with

Vulcanian A Vulcanian eruption is a type of volcanic eruption characterized by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. They usually commence with phreatomagmatic eruptions which can be extremely noisy due t ...

and

phreatomagmatic Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

eruptions, which deposited

pyroclastic Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroc ...

materials around the volcano. Short lava flows with lengths of on average were also produced and display flow structures such as levees and lobes. Some of the flows are covered with sediments. The decline of the ice cover during the Holocene and an increased distance between glaciers and volcanic vents may have been responsible for this change in eruption style.

Historical activity

Records of activity at Tupungatito go back to 1646 but its eruption record is poorly known, owing to its inaccessible location. Sometimes, eruptions at Tupungatito were incorrectly attributed to Tupungato. With over 19 eruptions between 1829 and 1987, Tupungatito is one of the SVZ's most active volcanoes. The historical eruptions took place in the craters north of the caldera, and involved in total eight craters. The intensity of the eruptions did not exceed a Volcanic Explosivity Index of 2. Many eruptions appear to be linked to tectonic events in Central Chile. In 1835,

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended ...

in his diary mentioned a

muleteer An ''arriero'', muleteer, or more informally a muleskinner ( es, arriero; pt, tropeiro; ca, traginer) is a person who transports goods using pack animals, especially mules. Distribution and function In South America, muleskinners transport ...

telling him that he had seen smoke coming from close to

although he crossed the Andes close to Portillo de los Piuquenes rather than the Alto Colorado; this is almost certainly a reference to Tupungatito. In 1962 the volcano was reportedly smoking. Eruptions at Tupungatito frequently deposited

in Mendoza. In 1958-1961 the volcano produced a long lava flow in Chile and

ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non-gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...

fall in San Martin, Argentina, away. There is also evidence of

ionospheric The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an ...

impacts from this eruption. The 1961 and 1964 eruptions formed one crater each, with the 1964 crater located directly south of the 1961 one. A third crater was the site of the three last eruptions in 1980, 1986 and 1987. The 1986 eruption deposited a thin ash layer over glaciers in the area. The last activity took place in 1987.

Present-day status and threats

The volcano is fumarolically active in four craters, the fumaroles mainly emit

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporizatio ...

at temperatures of . Gas bubbling has been observed in the crater lakes. The crater lakes and/or fumaroles are visible in

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioiso ...

images, where they appear as temperature anomalies. The gases come from the

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...

, ultimately from the downgoing

, and as they ascend they interact and mix with an overlying

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characte ...

and 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. There is also shallow

seismicity Seismicity is a measure encompassing earthquake occurrences, mechanisms, and magnitude at a given geographical location. As such, it summarizes a region's seismic activity. The term was coined by Beno Gutenberg and Charles Francis Richter in ...

around the volcano. Since 2012, the volcano is monitored by the Southern Volcanological Observatory of the Andes. Intense eruptions could melt the ice on the volcano through the emission of incandescent rocks and

s, producing medium-sized or long lahars in the Quebrada de Tupungatito and Estero del Azufre valleys.

Pyroclastic Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroc ...

fallout from high

eruption column An eruption column or eruption plume is a cloud of super-heated ash and tephra suspended in gases emitted during an explosive volcanic eruption. The volcanic materials form a vertical column or plume that may rise many kilometers into the ai ...

s would most likely occur in Argentina. Future eruptions will most likely be small or medium-sized Strombolian eruptions. The nearest towns in Chile are El Alfalfal, El Manzano and Los Maitenes and in Argentina La Consulta, San Carlos, Tunuyan and Tupungato. For Argentina, it is the 4th most dangerous volcano, and for Chile, the 22nd most dangerous volcano. Due to a combination between its relative proximity to population centres, high volume of ice and frequency of eruptions, a 2020 study ranked it the 4th most dangerous volcano on Earth in terms of lava-ice interactions. Eruptions may also endanger tourists.