Taftan (, ''Taptân'', , ''Taftân'', in Balochi and also

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

for "blistering, smoldering, fuming") is an

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 ...

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 ...

in south-eastern

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

in the Sistan and Baluchestan province. With variable heights reported, all around 4,000 metres (13,000 ft) above sea level, it is the highest mountain in south-eastern Iran. The nearest city is Khash. Taftan has two main summits, Narkuh and Madehkuh, and various heights have been reported for both summits. The northwestern Narkuh has two craters and is the older of the two summits. The southeastern Madehkuh summit is surrounded by fresh-looking

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 has at least three craters. The principal rock at Taftan is

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 ...

. Reports of historical volcanic activity are unclear and the youngest

radiometric Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which ch ...

dates are 6,950 ± 20 years before present. Currently, the volcano features vigorous

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

activity that is visible from a great distance and involves numerous vents on Materkuh. Taftan appears to be part of a geothermal area; there are a number of

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 around the volcano. Taftan is part of a

volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...

in Iran, together with

Bazman Bazman (, also known as Kuh-e Bazman) is a dormant stratovolcano in a remote desert region of Sistan and Baluchestan Province in southeastern Iran. A 500-m-wide crater caps the summit of the dominantly andesitic-dacitic volcano, the flanks of ...

, also in Iran, and Koh-i-Sultan in Pakistan. This volcanic arc has formed on

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

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

sedimentary layers and has resulted from the

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

of the

oceanic Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places * Oceanic, British Columbia, a settlement on Smith Island, ...

Arabian Plate beneath Iran at the

Makran trench The Makran Trench is the physiographic expression of a subduction zone along the northeastern margin of the Gulf of Oman adjacent to the southwestern coast of Balochistan of Pakistan and the southeastern coast of Iran. In this region the oc ...

Geography and geology

Taftan is in Iran's Sistan and Balochistan province. Closest cities are Khash south and

Zahedan Zahedan (Balochi language, Balochi and ; ) is a city in the Central District (Zahedan County), Central District of Zahedan County, Sistan and Baluchestan province, Sistan and Baluchestan province, Iran, serving as capital of the province, th ...

north north-west. In 1844, Abdul-Nabi reported of the existence of the mountain, as well as its volcanic activity. In 1971, it was reported that some Beluch tribes camp on Taftan's slopes outside of winter.

Regional setting

Volcanic activity has occurred in parts of Iran since the Cretaceous

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

. During the Eocene and

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 ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

s, volcanic activity reached its maximum, with thick pyroclastic layers being deposited in central Iran and the

Alborz The Alborz ( ) range, also spelled as Alburz, Elburz or Elborz, is a mountain range in northern Iran that stretches from the border of Azerbaijan along the western and entire southern coast of the Caspian Sea and finally runs northeast and merge ...

mountains. The area around Taftan volcano belongs to a

tectonic Tectonics ( via Latin ) are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of ''planetary tectonics'' extends the concept to other planets and moons. These processes ...

zone which is variously referred to as the Sistan suture or the Zabul-Baloch zone. There, after a previous episode of

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

ing and subsequent formation of an ocean, the Neh and Lut tectonic blocks collided during the Eocene epoch after a subduction episode that commenced in the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

age. Volcanic activity at Taftan itself appears to relate to the subduction of the Arabian Plate beneath the Central Iran Plate, occurring at a pace of or at the Makran trench. This subduction is also responsible for volcanism at Bazman in Iran and Koh-i-Sultan in Pakistan; this chain is known as the Baluchistan volcanic arc. The volcanism appears to not align with pre-existent structural trends in the basement. This subduction has also created an

accretionary wedge An accretionary wedge or accretionary prism forms from sediments accreted onto the non- subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the ...

that forms the

Makran Makran (), also mentioned in some sources as ''Mecran'' and ''Mokrān'', is the southern coastal region of Balochistan. It is a semi-desert coastal strip in the Balochistan province in Pakistan and in Iran, along the coast of the Gulf of Oman. I ...

region. The convergence of the two blocks continued even after their collision, generating

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 tectonic ...

s. The Saravan fault east of Taftan is one such fault; the 2013 Saravan earthquake occurred on this fault. From some of these faults it has been inferred that the mass load from the Taftan edifice has measurable effects on tectonic stress within the region.

Local setting

Taftan is the highest mountain in southeast Iran. The topography is overall steep. Deep valleys with U and V shapes have developed on Taftan, and the volcano has a strongly eroded appearance. One of these valleys, Tamindan, may be the Damindan valley in the

Avesta The Avesta (, Book Pahlavi: (), Persian language, Persian: ()) is the text corpus of Zoroastrian literature, religious literature of Zoroastrianism. All its texts are composed in the Avestan language and written in the Avestan alphabet. Mod ...

religious texts. One series of

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

s surrounding Taftan which reaches thicknesses of and reaches distances of from the edifice may be 2 million years old. The basement of Taftan is formed by various

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

s, along with some

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 ...

volcanic rocks and

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 ...

rocks. At Taftan, the Nehbandan-Khash

flysch Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building ep ...

borders the Makran zone. The oldest rocks are

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

s from the Cretaceous period. The crust beneath Taftan is approximately thick. The main edifice is constructed on top of the Eocene flysch, although some Cretaceous sediments are also part of the basement. Much of these rocks is coloured pink by

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

. The 19 mya old Mirabad

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

pluton In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

may be associated with Taftan; it could be the remnant of a Miocene volcano. Volcanic rocks 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), as well as the current and most recent of the twelve periods of the ...

age are widespread in the area. Taftan is a volcano with several summits; the highest two are separated by a saddle and are named Narkuh or Narkooh and Materkuh or Madekooh, which are apart. Narkuh is high and Materkuh . There are different heights reported for the summits, some of them placing Materkuh as the higher of the two: for example more recent Iranian maps cited in 2004 show Narkuh with a height of and Materkuh with a height of , while Gansser in 1964 indicated a summit height of . Another report from 1931 claimed a summit height of , a report in 1976 stated , and a map in 2004 claimed a measurement of . These summits rise above the surrounding plains. Narkuh has two craters, the northern of which is lower and is the source of more lava flows than the southern. The northwest Narkuh cone from 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 ...

age is highly eroded, while the southeastern Materkuh cone has fresh appearing

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

s and displays

solfataric 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 volcan ...

activity. Materkuh has three principal craters, although the eastern side of the eastern crater has also been affected by erosion. Alternatively, an explosive eruption removed the eastern side and generated a steep ravine. The northern crater has been the source of lava flows, some of which are well preserved and reach lengths of . In general, thick andesitic lava flows cover Materkuh. In 1893 and 1914,

Percy Sykes Brigadier-General Sir Percy Molesworth Sykes, (28 February 1867 – 11 June 1945) was a British soldier, diplomat, and scholar with a considerable literary output. He wrote historical, geographical, and biographical works, as well as describin ...

described a summit plateau with a surface of , at the side of which lay the two summits Ziaret Kuh ("Hill of Sacrifice", where pilgrims sacrificed goats) and Madar Kuh ("Mother Hill", containing fumaroles according to the 1893 report). Fumarolic alteration of the summit area has generated sulfur and

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

deposits which resemble snowcap. One report in 1893 indicated that the summit area of the volcano was covered with ash from upwards. 990803-Taftan-IMG 5873-2

The bulk of the volcano is formed by lava flows, along with

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, with dacites and pyroclastics lying on top of the Cretaceous-Eocene basement. These loose rocks formed by erosion, explosive activity and hot avalanches and are deposited in a large apron at the base of the volcano that extends over away from the central vents. Several fans of pyroclastic material, cemented by andesitic

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, surround the base of Taftan. Ignimbrites 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 are also present, including

breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...

s, nuee ardentes and tuffs. Volcanic rocks cover a surface of . There is also evidence of southeastern migration of the craters of Taftan, with Anjerk and Sardarya being more westerly vents. These preceding centres have left andesitic lava flows that are partially dissected and

agglomerate Agglomerate (from the Latin ''agglomerare'' meaning "to form into a ball") is a coarse accumulation of large blocks of volcanic material that contains at least 75% bombs. Volcanic bombs differ from volcanic blocks in that their shape records flui ...

s. The existence of a

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

at Taftan has been inferred. The table mountain Takht-i-Rostam south of Taftan may be the remnant of a basalt extrusion, but it doesn't appear to be related to Taftan. A

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 ...

may lie beneath the volcano.

Composition

Taftan has erupted lavas 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 Ameri ...

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. ...

. The dominant rock is andesite, with content ranging from 49.8 to 63.5%. Grey andesites form the youngest rocks on the main summit and contain

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

schist Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...

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 al ...

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

inclusions. The andesites are vesicular. The magma of Taftan volcano is very oxidized, as can be inferred from the composition of the surrounding ignimbrite and fumarole gases. The lavas of Taftan are porphyritic. Mineral components include biotite,

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 ...

hornblende Hornblende is a complex silicate minerals#Inosilicates, inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common ...

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

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 ...

and

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 ...

. Other components are

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a Mohs scale, hardness of 3.5 to 4 ...

, haematite,

ilmenite Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printi ...

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula . It is one of the iron oxide, oxides of iron, and is ferrimagnetism, ferrimagnetic; it is attracted to a magnet and can be magnetization, magnetized to become a ...

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 ...

. Complex

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 ...

assemblages found in a sample indicate that the magma formation is a complex process. Taftan rocks overall are

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 ...

, of sub–alkaline affinity. The magma that formed these rocks was influenced by crystal fractionation and mixing processes. Its composition has characteristics of volcanic arc magmas. Crustal materials were involved in the formation of the magma, with

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

isotope data indicating crustal assimilation. Fumarolic activity affects surrounding rocks and pyroclastics.

Carbonate A carbonate is a salt of carbonic acid, (), 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 group ...

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

, and white covers of possibly aluminum sulfate and

calcium sulfate Calcium sulfate (or calcium sulphate) is an inorganic salt with the chemical formula . It occurs in several hydrated forms; the anhydrous state (known as anhydrite) is a white crystalline solid often found in evaporite deposits. Its dihydrate ...

have been formed.

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 ...

formed from the sulfur of the volcano is found in the form of crystals in the upper valleys of Taftan. Sinter and hydrothermally altered rocks are found farther down. Minerals formed by alteration processes include

alunite Alunite is a hydroxylated aluminium potassium sulfate mineral, formula potassium, Kaluminium, Al3(sulfur, Soxygen, O4)2(Ohydrogen, H)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum ...

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

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 ...

illite Illite, also called hydromica or hydromuscovite, is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandw ...

jarosite Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct dur ...

kaolinite Kaolinite ( ; also called kaolin) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral sheet of alumina () ...

pyrophyllite Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. It occurs in two forms (habits): crystalline folia and compact masses; distinct crystals are not known. The folia have a pronounced pearly luster ...

, quartz,

smectite A smectite (; ; ) is a mineral mixture of various swelling sheet silicates (phyllosilicates), which have a three-layer 2:1 (TOT) structure and belong to the clay minerals. Smectites mainly consist of montmorillonite, but can often contain secon ...

, sulfur and

tridymite Tridymite is a high-temperature polymorphism (materials science), polymorph of silica and usually occurs as minute tabular white or colorless pseudo-hexagonal crystals, or scales, in cavities in felsic volcanic rocks. Its chemical formula is sili ...

. Some

epithermal 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 ...

mineralizations have been identified around Taftan. Other secondary factors at Taftan include

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 ...

Eruptive history

About five different active eruption periods have been discovered at Taftan volcano. Activity first involved lava and pyroclastics of dacitic to rhyodacitic composition. Later, upper

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 Three phases have been dated at 6.95 ± 0.72, 6.01 ± 0.15 and 0.71 ± 0.03 million years ago; an even older phase west-northwest of the current volcano occurred 8 million years ago, while a

ignimbrite has produced an age of 404,000 ± 82,000 years before present. The youngest dates have been obtained on lava flows and indicate ages of 6,950 ± 20 years ago, by

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...

. Research published in 1897 indicated the absence of very fresh lava flows but the authors inferred from the fresh ash that volcanic activity had occurred during the present geological epoch. That the name "Taftan" may be derived from an ancient Iranian word "taft" for "semi solid liquid material" could indicate that effusive activity was witnessed by the people of that time period around the volcano. It is not certain that there were any

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 ...

eruptions at Taftan, as clear evidence of such activity is missing. Eruptions are recorded in 1902, 1970 and 1993. A report of smoke emission in 1877 may have confused

clouds In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may c ...

for volcanic activity. In 1914, the volcano was described to be "belching out clouds of smoke", although a report in 1971 indicated the absence of historical activity. These eruptions were accompanied by earthquake activity. During the eruption of 1902, heavy smoke and a night time glow on the volcano were observed. The eruption in 1993 involved a long lava flow, but it may have been a flow of molten sulfur. The volcano is currently classified as a

dormant 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 often ...

. Satellite imagery indicates, however, that ground deformation occurs at Taftan. Unofficial volcano hazard maps have been developed.

Fumarolic and geothermal activity

Taftan displays vigorous

activity, with high temperature vents found around the crater. Fumaroles are found chiefly in the eastern and at the edge of the western crater, with minor fumaroles within the western crater, along some minor craters and along the major lava flow. These gas exhalations are known as "Dood" by local peoples and they appear as yellow-white clouds with a strong smell. The vents they come from have the shape of fissures, cracks and crevices. The larger fumaroles can reach diameters of . The occurrence of

hydrothermal explosion Hydrothermal explosions occur when superheated water trapped below the surface of the Earth rapidly converts from liquid to steam, violently disrupting the confining rock. Boiling water, steam, mud, and rock fragments are ejected over an area of ...

s has been inferred from the presence of

made up by volcanic rocks. Reportedly in 1897 the smell of the fumaroles was so strong as to be unbearable when one was close to the vents. One report mentioned in a magazine of 1899 indicated the presence of seven steam vents at an altitude of , produced audible noise. Their steam plumes were visible at distances of ; later reporting indicated visibility to distances of . Another report in 1999 found a solfatara surrounded by clay and sulfur deposits that looked like a snowcap. A fumarole field was described on the west side of the southeast cone, the venting clearly visible from a refuge farther down the mountain and covering a surface area of . The name "Taftan" is derived from these exhalations, which make the mountain appear to be burning. The overall gas composition found at Taftan includes , , and

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

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 ...

is present in high quantities in fumarolic gases, which also contain

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 ...

. These gases are hence extremely acidic. The fumaroles have altered rocks, forming highly colourful exposures especially on Taftan's eastern flank.

Ammonium chloride Ammonium chloride is an inorganic chemical compound with the chemical formula , also written as . It is an ammonium salt of hydrogen chloride. It consists of ammonium cations and chloride anions . It is a white crystalline salt (chemistry), sal ...

(''salmiak'') and sulfur has been collected around fumaroles. The thick sulfur layers on the southeastern summit were formerly extracted for use in Iran and Pakistan. Sulfur and sulfate deposits are also found lower on the volcano, from hot springs around Gooshe, at Sangān and Torshāb. Hot springs are also found at Taftan, especially at over altitude. An analysis of five springs in May 2012 indicated temperatures of and flow rates of . The waters are very acidic due to the formation of from magmatic gases, including the oxidation of . The hot waters around Taftan contain large quantities of

boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...

, probably because the hydrothermal system of Taftan is young and receives input of host rocks containing

. They are influenced by the fumarolic gases, as well as by volcanic rock composition. Some of the water in the area is juvenile, with magmatic water forming up to 20% of the water. Temperatures in the hydrothermal system are estimated to be between and . The composition of the water in various springs around Taftan varies in terms of elemental composition, probably reflecting the mixing between volcanic and meteoric waters and interaction with host rocks and

brine Brine (or briny water) is a high-concentration solution of salt (typically sodium chloride or calcium chloride) in water. In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawat ...

s. The geothermal area of Taftan is among the largest in the Makran zone of Iran; it covers a surface area of . Other geothermal manifestations in southeastern Iran have been found at Bazman.

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

s are also found at Taftan. Probably due to decreased precipitation, before 2002 a trend to increased steam and decreased water release has been observed, especially in the upper part of the geothermal system. Hot springs and other geothermal manifestations are widespread in Iran and using them to gain geothermal energy has been studied; according to a report of 2002 hot springs at that time were mainly used for therapeutic purposes and bathing. A report in 2002 indicated that Taftan may be a feasible place to install a

binary cycle A binary cycle is a method for generating electrical power from geothermal resources and employs two separate fluid cycles, hence binary cycle. The primary cycle extracts the geothermal energy from the reservoir, and secondary cycle converts the h ...

power plant.

Climate and vegetation

The climate at Taftan features cold winters accompanied by

snowfall Snow consists of 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 througho ...

when temperatures drop below freezing between December and February, and hot summers with temperatures during July and August exceeding . Taftan is located in an

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

locale but has more precipitation than the surrounding area, thus providing water to the surrounding terrain. Average precipitation is per year. Owing to the height of the mountain, there are distinct vegetation belts at Taftan. The lowlands around the mountain are covered with '' Artemisia'' steppe and occasional

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

. Open

scrubs Scrub(s) may refer to: * Scrub, low shrub and grass characteristic of scrubland * Scrubs (clothing), worn by medical staff * ''Scrubs'' (TV series), an American television program * Scrubs (occupation), also called "scrub tech," "scrub nurse," ...

occur in a higher altitude belt of where the terrain is rocky, and thorn- cushion vegetation at elevations of ; there is little vegetation in the summit area. The summit of Taftan and several other Iranian volcanoes were deemed national natural monuments in 2002. File:990803-Taftan-IMG 5829-2.jpg, alt=Taftan Summit, Taftan Summit, Sistan and Baluchestan province,

File:990803-Taftan-IMG 5963-2.jpg, alt=Mount Taftan, Mount Taftan, Sistan and Baluchestan province,

File:990802-Taftan-IMG 5812-2.jpg, alt=Taftan Shelter, Taftan Shelter, Mount Taftan, Sistan and Baluchestan province,

File:990803-Taftan-IMG 5873-2.jpg, alt=Taftan Summit, Taftan Summit, Sistan and Baluchestan province,

File:990803-Taftan-IMG 5851-2.jpg, alt=Taftan Summit, Taftan Summit, Sistan and Baluchestan province,

File:990802-Taftan-IMG 5804-2.jpg, alt=Sulfur in Taftan mountain, Sulfur, Taftan Mountain, Sistan and Baluchestan province,

References

Sources

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External links

"Kuh-e Taftan, Iran" on Peakbagger
{{Protected Areas of Iran Stratovolcanoes of Iran Mountains of Iran Mountaineering in Iran Landforms of Sistan and Baluchestan province Pleistocene stratovolcanoes Tourist attractions in Sistan and Baluchestan province Mountains of Sistan and Baluchestan Province