Cerro Tuzgle is a dormant

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 ...

in the Susques Department of

Jujuy Province Jujuy is a province of Argentina, located in the extreme northwest of the country, at the borders with Chile and Bolivia. The only neighboring Argentine province is Salta to the east and south. Geography There are three main areas in Jujuy: * ...

in northwestern Argentina. Tuzgle is a prominent volcano of the

back-arc A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of ...

of the

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 ...

and lies about east of the main volcanic arc. 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 American ...

of the Andes, it is high above sea level and grew during different stages over a

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

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. Some major lava flows emanate from the summit

crater Crater may refer to: Landforms * Impact crater, a depression caused by two celestial bodies impacting each other, such as a meteorite hitting a planet * Explosion crater, a hole formed in the ground produced by an explosion near or below the surf ...

, and one confirmed and one possible flank collapse unit as well as an

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 surro ...

sheet are associated with this volcano. The first volcanic activity of Tuzgle occurred 650,000 years ago and formed the Tuzgle Ignimbrite. Subsequently, lava domes were erupted and several lava flows; scientists have proposed two different schemes of naming the units. The latest lava flows are dated at 300,000 years ago and volcanic activity may have continued into the

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 ...

. Several thermal springs are associated with the volcano, and some have been investigated for possible

geothermal energy Geothermal energy is the thermal energy in the Earth's crust which originates from the formation of the planet and from radioactive decay of materials in currently uncertain but possibly roughly equal proportions. The high temperature and pr ...

production.

Sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

was formerly mined on the mountain.

Geography and geomorphology

Cerro Tuzgle is a volcano near the eastern border of the Argentina Puna. Politically, it is part of the Susques Department of the

San Antonio de Los Cobres San Antonio de los Cobres is a small town of population 5,482 (per the 2001 INDEC census) in northwestern Argentina. It is the capital of the Los Andes Department of the Salta Province. Geography The town is known for its high elevation of app ...

lies from Cerro Tuzgle and Susques , while the cities of Salta and

San Salvador de Jujuy San Salvador de Jujuy (), commonly known as Jujuy and locally often referred to as San Salvador, is the capital and largest city of Jujuy Province in northwest Argentina. Also, it is the seat of the Doctor Manuel Belgrano Department. It lies near ...

are and away, respectively. A locality called "Sey" lies northwest of Cerro Tuzgle. The volcano is visible from Provincial Route 74. Its name, which is also rendered as , or , comes from the

Kunza language Kunza is an extinct language isolate once spoken in the Atacama Desert of northern Chile and southern Peru by the Atacama people, who have since shifted to Spanish. The last speaker was documented in 1949. Other names and spellings include C ...

; it means "knoll" and refers to the shape of the volcano. Cerro Tuzgle is a simple volcanic cone and is the largest in the

region of the Andes. It is a well-preserved

that rises from a surrounding terrain at elevation to a summit at elevation. A platform lies at the summit of the volcano. The mountain is occasionally snow-covered and

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a g ...

weathering has produced patterned ground and

blockfield A blockfieldWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, pp. 66 and 190. . (also spelt block fieldLeser, Hartmut, ed. (2005). ''Wörterbuch Allgemeine Geographie'', 13th ed., dtv, Munich, pp. 107 and 221. ...

s. In 1926 it was reported that a

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 ...

lies on the summit. Three east-west trending

fissure vent A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilo ...

s in the summit area are the source of dark lava flows that flowed southward and southwestward, and are flanked by high

scoria 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) '' ...

ridges. The

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 that make up the volcanic cone are blocky, rich in crystals and have variable appearances. Numerous young-looking lava flows descend the slopes of Cerro Tuzgle. A well-preserved lava flow descends the mountain and is visible on its southern flank. Older flows reached distances of from the volcano. A long

scarp Scarp may refer to: Landforms and geology * Cliff, a significant vertical, or near vertical, rock exposure * Escarpment, a steep slope or long rock that occurs from erosion or faulting and separates two relatively level areas of differing elevatio ...

runs across the northwestern flank of Cerro Tuzgle and separates two units of lava flows; it probably formed through a localized collapse of the volcanic edifice in this sector. A depression in the southern flank of the volcano may also be evidence of a collapse in that direction. A

parasitic vent A parasitic cone (also adventive cone or satellite cone) is the cone-shaped accumulation of volcanic material not part of the central vent of a volcano. It forms from eruptions from fractures on the flank of the volcano. These fractures occur ...

is located on the western foot of the volcano. There are abandoned

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

mines on Cerro Tuzgle, which are visible from its south-southwestern flank; these include Mina Betty on the northwestern flank between elevation where in 1939 seven sulfur outcrops were reported. A road transitable by trucks was constructed at that time to reach the summit area. The volcano rises in a north-tilted, north-south trending tectonic depression, which is delimited by

normal 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 tectonic ...

s and two horsts north and south of Cerro Tuzgle. The region is

endorheic An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...

and drainages ultimately end in salt pans. The Quebrada Aguas Calientes passes west and Quebrada de Charcos east of the volcano; the latter becomes Quebrada Los Charcos north of the volcano and converges with Quebrada Aguas Calientes. Drainage around the volcano is focused by surrounding ridges into a watershed that drains northward, and contains permanent rivers fed by

spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a h ...

s at the bottom of valleys.

Carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...

deposits and

thermophilic A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...

have been reported from the Quebrada Aguas Calientes. Peatland-lake complexes occur southeast of Cerro Tuzgle.

Geology

Along the west coast of South America, 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 ...

subducts 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 ...

in an east-northeast direction 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 ...

in the Peru-Chile Trench, at a rate of . The subduction process is responsible for the volcanic activity in the Andes, which occurs in four volcanic belts, from north to south these are 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

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 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 Central Andes are subdivided into three sectors: the Western Cordillera with the active volcanic arc, the wide Altiplano- Puna high plateau and the Eastern Cordillera-Subandean Ranges. The high plateau began to form in the

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

–

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

due to tectonic shortening of the Andes. Volcanic activity is distributed between the Western Cordillera and the Altiplano-Puna high plateau, where

strike-slip 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 and

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

faults organize magma ascent. The tectonic regime in the area has changed over time and now the volcano lies just north of a transitional zone which separates steep subduction farther north from shallow subduction farther south. During the

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 ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58crust failed, allowing the uplift of the region and the injection of fresh magma that triggered extensive volcanic activity. During that time, the Subandean Ranges and the Eastern Cordillera formed. Later, during the Pliocene, subduction became steeper and volcanism shifted westward, and the composition of the remnant volcanism changed along with a change in the tectonic regime from uplift and east-west directed compression to north-south directed spreading and east-west directed compression. Volcanic activity also changed; between 17.5 and 5.3 million years ago it took place over the entire area whereas from 1.5 million years ago it has focused on the central-eastern Puna plateau. Between these two phases, sedimentation occurred and formed the Pastos Chicos Formation.

Local

Cerro Tuzgle is part of the back-arc of the Andean Central Volcanic Zone, being about east of the main volcanic arc, and its largest

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 ...

member. Other volcanic cones in the area are San Jerónimo volcano and Negro de Chorrillos, which erupted 780,000±100,000 and 200,000±150,000 years ago, respectively, Tocomar, which erupted 1.5–0.5 million years ago, and

Aguas Calientes caldera Aguas Calientes is a major Miocene caldera in Salta Province, Argentina. It is in the Central Volcanic Zone of the Andes, a zone of volcanism covering southern Peru, Bolivia, northwest Argentina and northern Chile. This zone contains stratovo ...

. All these volcanoes are located south of Cerro Tuzgle. Extensive volcanic rocks of Miocene to Pliocene age occur in the area, which were erupted by volcanoes such as Aguas Calientes caldera and Cerro Queva. Older rocks belong to the Faja Eruptiva

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

age. The total thickness of the crust reaches . 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, ...

is formed by

Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago ...

and

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, 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 th ...

formations of

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

character, such as the

Puncoviscana Formation Puncoviscana Formation ( es, Formación Puncoviscana) is a formation of sedimentary and metasedimentary rocks Late Ediacaran and Lower Cambrian age, estimated at between 700 and 535 Ma, that crop out in the Argentine Northwest. Most of the form ...

. A large tectonic

lineament ''See also Line (geometry)'' A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-alig ...

, the Calama-Olacapato-El Toro lineament, intersects the Andes at Cerro Tuzgle. It reaches from the

forearc Forearc is a plate tectonic term referring to a region between an oceanic trench, also known as a subduction zone, and the associated volcanic arc. Forearc regions are present along a convergent margins and eponymously form 'in front of' the v ...

in Chile across the mountain range into the foreland of the Andes in Argentina, and it separates the northern from the southern Puna. The distribution and history of volcanic activity differs between these two regions. Other similar faults cut across the Andes. The Calama-Olacapato-El Toro lineament is a strike-slip fault that consists of several separate faults, some of which show evidence of Quaternary activity and could produce earthquakes. Within the Andes proper, this activity mainly occurs in the form of normal faulting; only south of Cerro Tuzgle is there a segment with strike-slip faulting. Movement along most of these faults appears to clamp the magma chamber and magma conduits at Cerro Tuzgle, thus impeding volcanic activity there.

Gravimetric Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of a gravitational field or the properties of matter responsible for its creation are of interest. Units of measurement G ...

and

magnetotelluric Magnetotellurics (MT) is an electromagnetic geophysical method for inferring the earth's subsurface electrical conductivity from measurements of natural geomagnetic and geoelectric field variation at the Earth's surface. Investigation depth ra ...

surveys have identified a partially molten

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 ...

between depth, which also contains saline fluids.

Seismic tomography Seismic tomography or seismotomography is a technique for imaging the subsurface of the Earth with seismic waves produced by earthquakes or explosions. P-, S-, and surface waves can be used for tomographic models of different resolutions based on ...

has identified zones with anomalously low

seismic velocity A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. ...

which descend from Cerro Tuzgle to depth in the downgoing

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 ...

Composition

Cerro Tuzgle has mainly 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 predo ...

and

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 constitute a crystal- and

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 with seriate flux and

porphyritic Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning a ...

textures. The rocks contain large

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) felds ...

and

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

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 and small phenocrysts of

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 ...

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 ...

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 ...

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 ...

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 ...

Xenolith 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 and

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 are also found 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 ...

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 s ...

and

zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of t ...

have been reported. At Aguas Calientes, sinters consisting of boronatro-

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

chalcedony Chalcedony ( , or ) is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monocli ...

and

opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline form ...

occur. A

cesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that ar ...

-rich pharmacosiderite-like mineral has been found at a hot spring. Different rock units have different phenocryst components and

trace element __NOTOC__ A trace element, also called minor element, is a chemical element whose concentration (or other measure of amount) is very low (a "trace amount"). They are classified into two groups: essential and non-essential. Essential trace elements ...

compositions. The rocks of Cerro Tuzgle are the most diverse volcanic rocks in the back-arc of the Central Andes. One unusual mineral is

caesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that a ...

-containing pharmacosiderite. Magma mixing processes involving fractionating

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 in ...

magmas and crystallization have been invoked to explain the origin of Cerro Tuzgle's magmas. The parent magmas originated in the

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

and the crust, with the crustal parts joining the mantle-derived magmas in the deep crust. These crustal components originally came from the upper crust and reached the lower crust during tectonic processes. At this stage crystal fractionation also took place. The ascending magmas then accumulated in the crust and either erupted or were assimilated by ascending mafic magmas.

Climate and vegetation

The climate is cold, owing to Cerro Tuzgle's high elevation, and the diurnal temperature range reaches . Winds blow mainly from the west and reach . During winter,

insolation Solar irradiance is the power per unit area ( surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre ...

is high, cloud cover and precipitation are low and strong winds blow through the area. According to 1939 reports,

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are some ...

s and snowfall are common at Cerro Tuzgle. The region is

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

, with less than annual precipitation as it is part of the Andean

Arid Diagonal upright=2.5, Map showing Köppens climate classification for South America. The arid diagonal can be seen in the form of the almost contiguous zone of BWh and BWk climate running from Ecuador to Southern Patagonia. The Arid Diagonal ( es, link=n ...

where the Eastern Cordillera prevents moisture-bearing winds from reaching the Puna. The little precipitation that falls originates in the Atlantic Ocean and the

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

and arrives during the

summer monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscill ...

; additionally

cold front A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure. It often forms behind an extratropical cyclone (to the west in the Northern ...

s come from 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 ...

over the Pacific Ocean. The amount of precipitation is influenced by the

El Niño-Southern Oscillation EL, El or el may refer to: Religion * El (deity), a Semitic word for "God" People * EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer * El DeBarge, music artist * El Franco Lee (1949–2016), American ...

, where El Niño is associated with drought and La Niña with wetter weather. Vegetation is sparse and consists of

tola Tola may refer to: Places * Bella Tola, a mountain in the Pennine Alps in the Swiss canton of Valais * La Tola, a town and municipality in the Nariño Department, Colombia *Tola (Shakargarh), a village in Pakistan * Tola, Rivas, a municipality ...

, ''

Vachellia caven ''Vachellia caven'' (Roman cassie, , aromo criollo, caven, , , espinillo, espinillo de baado, espino, espino maulino) is an ornamental tree in the family Fabaceae. ''Vachellia caven'' is native to Argentina, Bolivia, Chile, Paraguay, and Urugua ...

'' and yareta. Animals that live in the area include

chinchilla Chinchillas are either of two species (''Chinchilla chinchilla'' and ''Chinchilla lanigera'') of crepuscular rodents of the parvorder Caviomorpha. They are slightly larger and more robust than ground squirrels, and are native to the Andes moun ...

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

coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...

Darwin's rhea Darwin's rhea or the lesser rhea (''Rhea pennata'') is a large flightless bird, the smaller of the two extant species of rheas. It is found in the Altiplano and Patagonia in South America. Description The lesser rhea stands at tall. Leng ...

s, ducks,

eagle Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, j ...

s, ''Galea'' species,

guanaco The guanaco (; ''Lama guanicoe'') is a camelid native to South America, closely related to the llama. Guanacos are one of two wild South American camelids, the other being the vicuña, which lives at higher elevations. Etymology The guanaco ...

llama The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era. Llamas are social animals and live with others as a herd. Their wool is soft ...

s, suris and

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

s. ''

Trichomycterus ''Trichomycterus'' is a genus of fish in the family Trichomycteridae, the largest genus of its family with over 170 species currently described. This genus is native to freshwater habitats in Central and South America. These fish are generally sm ...

'' fish have been found in creeks around the volcano.

Peatland A mire, peatland, or quagmire is a wetland area dominated by living peat-forming plants. Mires arise because of incomplete decomposition of organic matter, usually litter from vegetation, due to water-logging and subsequent anoxia. All types ...

s are dominated by the plants '' Oxychloe andina'', ''

Distichia muscoides ''Distichia muscoides'' is a species of plant in the rush family Juncaceae. It is native to the Andes of South America where it grows in upland wetland areas known as bofedales. Description ''D. muscoides'' is a cushion plant, forming sheets ...

'' and '' Zameioscirpus muticus'', with other

cyperaceae The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

being subordinate. Annual precipitation there amounts to , almost all of which falls during October to March. Peatlands close to Cerro Tuzgle have been used to reconstruct the local climate during the

. Reconstructed past precipitation levels show alternations between wetter and drier periods during the last 1,800 years, with the last 130 years being relatively dry.

Eruption history

Cerro Tuzgle was active during the

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 ...

and its most recent eruption may have followed a period of inactivity. With the exception of one flow, most are partially degraded and buried by wind-transported material. Volcanic activity took place in multiple stages: * First, a

rhyodacitic Rhyodacite is a volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of those plutonic rocks that are intermediate in composition between monzogranite and granodiorite. Rhyodacites form from rapid ...

with a volume of was erupted and flowed north over the pre-existing terrain, forming a thick plateau. This homogeneous ignimbrite has a yellow-white colour; the middle and upper parts of the ignimbrite contain

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...

and the lower part contains lithic fragments. It has been dated to be 650,000±180,000 years old and was presumably erupted from a small

now buried under Cerro Tuzgle. *

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 of

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 rhyol ...

composition with a total volume of about were emplaced on the rim of the caldera, forming the "Old Complex". The "Old Complex" was erupted about 300,000 years ago. The domes crop out north, south and southeast from the volcano and are reddish-brown to light grey in colour. The lava flows are homogeneous and feature flow structures and laminations. Two schemes for classifying the subsequent activity have been proposed, the first: *

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 predomin ...

lava flows partially buried the lava domes, forming the "Pre-platform unit". It has been dated to be 300,000±1,000,000 years old. * Mafic andesite lava filled the caldera. It constitutes the prominent "Platform unit". * Northwest-southeast directed faulting dissected the volcano, and the "Postplatform" and "Young Flow" units were erupted along these faults. A latite lava flow has yielded ages of 100,000±100,000 and 100,000±300,000 years old. The "Young Flow" unit is considered to be of Holocene or Pleistocene-Holocene age, and is represented by multiple young lava flows. A substantially different reconstruction was provided by Gianluca Norini ''et al'' in 2014: * Six units of massive, up to thick, dark grey to reddish-brown coloured lava flows form the San Antonio Synthem. This unit crops out on the southern and northwestern side of the volcano, which at this stage already had a major topographic expression. A fan formed by volcanic debris attributed to this stage covers an area of north of Cerro Tuzgle; it probably formed during a large collapse of the volcanic edifice that removed about of its volume and generated the scarp on the northwestern flank. * After an episode of erosion, the Azufre Synthem was emplaced around the summit. It consists of massive, up to thick, dark grey to reddish-brown coloured lava flows. These lava flows are sometimes

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 ...

ly altered; the sulfur deposits on the volcano are linked to this synthem. * Faulting and hydrothermal alteration took place after the emplacement of the Azufre Synthem. 13 units of lava flows form the Tuzgle Synthem. These aa and

block lava 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 und ...

flows reach thicknesses of and are the last stage of volcanic activity at Cerro Tuzgle. A stage of

solfataric 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 ...

activity followed the last eruptions and deposited

The "Old Complex" has a volume of , the subsequent units only reach . There is a trend from voluminous ignimbrites and dacites, formed through melting of the crust at high temperatures, early in the volcano's history to less voluminous mafic magmas, which erupted through brittle faults.

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 ...

deposits east of San Antonio de los Cobres may have originated at Tuzgle. The volcano is presently inactive. The Argentina geological service SEGEMAR considers Cerro Tuzgle among the more dangerous volcanoes in Argentina, ranking it 11th out of 38. While the region is thinly inhabited, the occurrence of a sector collapse at Cerro Tuzgle implies that mining and geothermal energy exploitation efforts in the area could be imperiled by similar future events.

Geothermal activity

Springs occur at Agua Caliente de Tuzgle northwest from the summit, and at Mina Betty () south-southeast. Both emit alkaline waters containing

chloride The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride s ...

at temperatures of and , respectively. Agua Caliente de Tuzgle also emits gases and has produced sinter deposits. The Antuco hot springs southwest from Cerro Tuzgle may receive their heat from Cerro Tuzgle. These springs and other springs in the Tuzgle area are recharged by precipitation on surrounding ridges; large-scale fracture systems in the ground control its flow and water emerges in proximity to deeply incised valleys which provide the path for water to reach the surface. Temperatures at depth exceed .

Tourism, mining and geothermal potential

Hot springs such as Pompeya and Tocomar might be used for tourism, as they are located close to the main roads of the area. The volcano might also be a suitable target for

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, ...

; its ascent poses little difficulty to trained mountaineers.

Inca The Inca Empire (also known as the Incan Empire and the Inka Empire), called ''Tawantinsuyu'' by its subjects, ( Quechua for the "Realm of the Four Parts", "four parts together" ) was the largest empire in pre-Columbian America. The adm ...

ceremonial sites in the form of a raised platform and structures formed by piled-up rocks on the summit region were reported by María Constanza Ceruti in 1999. Neighbouring volcanoes as well as the Nevado del Chañi ridge are visible from the summit. The first findings of sulfur occurred in 1924, but they were not immediately exploited. A mining concession for Mina Betty was issued in 1933, while approval for two other proposed mines in the summit area was still pending in 1939. The machinery required for sulfur processing was installed south-southeast of the volcano and the site bore the name "Ojo del Tuzgle"; the sulfur was transported there either by

mule The mule is a domestic equine hybrid between a donkey and a horse. It is the offspring of a male donkey (a jack) and a female horse (a mare). The horse and the donkey are different species, with different numbers of chromosomes; of the two po ...

s or by trucks. A spring there was used as a water source for mining activities. During parts of the year bad weather conditions rendered mining impossible. In the 1970s and 1980s numerous companies prospected the area for

geothermal power Geothermal power is 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 is currently used in 2 ...

generation. They established the presence of two superposed heat reservoirs, one at depth in an older ignimbrite and another at depth in Ordovician-age rocks. Initially they were interpreted as a joint Tocomar-Tuzgle geothermal system before these were identified as separate systems in 2008 and 2016. A major

power line An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...

between Argentina and Chile runs across the area, and local mines along with the towns of Olacapato and San Antonio de Los Cobres could provide a market for geothermal power. Private companies are active in conducting feasibility studies. A potential yield of 28–34

megawatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...

s of electrical power has been estimated, but no progress towards exploiting these resources has been made. The geothermal vents could also be used to extract minerals or for spas. Concerns have been raised that the sensitive ecosystems might be threatened by human activity.

Notes

References

Sources

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External links

* {{DEFAULTSORT:Tuzgle, Cerro Mountains of Argentina Polygenetic volcanoes Stratovolcanoes of Argentina Subduction volcanoes Pleistocene stratovolcanoes