Taftan Volcano

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Taftan
Koh-i-Taftan ("Mountain of Taftan"),[1] The Boiling Mountain,[2] Ziyārat.[3] Koh-I-Chehaltan ("Mountain of the Forty Beings"[4]).[5]
Taftan Volcano.jpg
Highest point
Elevation 3,941 m (12,930 ft) [6]
Prominence 2,901 m (9,518 ft) [6]
Ranked 109th
Isolation 389 kilometres (242 mi)
Listing Ultra
Coordinates 28°36′00″N 61°07′57″E / 28.60000°N 61.13250°E / 28.60000; 61.13250Coordinates: 28°36′00″N 61°07′57″E / 28.60000°N 61.13250°E / 28.60000; 61.13250[6]
Naming
Translation The place of heat[7]
Geography
Taftan is located in Iran
Taftan
Taftan
Iran
Location Sistan and Baluchestan, Iran.
Geology
Mountain type Stratovolcano
Last eruption Unknown

Taftan (Persian: تفتان‎‎, Taftân) is an active stratovolcano in south-eastern Iran situated 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 is a Balochi word which means "The Place of Heat".

Taftan has two main summits known as Narkuh and Materkuh. Varying heights have been reported for both summits. The northwestern Narkuh has two craters and is the older of the two summits. The southeastern Materkuh summit is surrounded by fresh-looking lava flows and has at least three craters. The principal rock at Taftan is andesite.

Reports of historical volcanic activity are unclear and the youngest radiometric dates are 0.71 ± 0.03 mya. The volcano however features vigorous fumarolic activity that is visible from a great distance and involves numerous vents on Materkuh. The volcano appears to be part of a geothermal area, and a number of hot springs can be found around Taftan.

Taftan is part of a volcanic arc in Iran together with Bazman volcano also in Iran and Koh-i-Sultan volcano in Pakistan. This volcanic arc is constructed on Cretaceous-Eocene sedimentary layers and results from the subduction of the oceanic Arabian plate beneath Iran at the Makran trench.

Geography and Geology[edit]

Taftan in Iran

Taftan is in Iran's Sistan and Balochistan province. Cities close to Taftan include Khash 45 kilometres (28 mi) south and Zahedan c. 100 kilometres (62 mi) north.[8] In 1971 it was reported that Beluch tribes camp on Taftan's slopes during the non-winter seasons.[9]

Regional setting[edit]

Volcanic activity in parts of Iran has been recorded since the Cretaceous.[10] During the Eocene-Oligocene volcanic activity reached its maximum, with thick pyroclastic layers being deposited in central Iran and the Alborz.[11] The area around Taftan volcano belongs to a tectonic zone which is variously referred to as the Sistan suture or Zabul-Baloch zone. There, after a previous episode of rifting and subsequent formation of an ocean, the Neh and Lut tectonic blocs collided in the Eocene after a subduction episode that commenced in the Maastrichtian. Volcanic activity at Taftan itself appears to relate to the subduction of the Arabian plate beneath the Central Iran plate,[12] occurring at a pace of 3.5–4.2 centimetres per year (1.4–1.7 in/year) at the Makran trench.[13] This subduction is also responsible for volcanism at Bazman in Iran and Koh-i-Sultan in Pakistan;[14] this chain is known as the Baluchistan volcanic arc.[13] The volcanism appears to not align with pre-existent structural trends in the basement.[11] This subduction has also created an accretionary wedge that forms the Makran region.[15]

The convergence of the two blocs continued even after their collision, generating strike-slip faults. The Saravan fault east of Taftan is a major such fault,[12] the 2013 Saravan earthquake occurred on this fault.[16] 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.[17]

Local setting[edit]

The basement of Taftan is formed by various sedimentary rocks, along with some mafic volcanic rocks and metamorphic rocks. At Taftan, the Nehbandan-Khash flysch borders the Makran zone.[8] The oldest rocks are limestones from the Cretaceous.[14] The crust beneath Taftan is approximately 60 kilometres (37 mi) thick.[18] The main edifice is constructed on top of the Eocene flysch,[12] some Cretaceous sediments are also part of the basement.[19] The 19 mya old Mirabad granite pluton may be associated with Taftan;[20] it could be the remnant of a Miocene volcano.[21]

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,[3] which are 2 kilometres (1.2 mi) apart.[22] Narkuh is 4,100 metres (13,500 ft) high and Materkuh 3,950 metres (12,960 ft).[23] Other measurements indicate Materkuh to be the higher summit, there are different heights reported for the summits,[3] for example more recent Iranian maps cited in 2004 showing Narkuh with a height of 3,840 metres (12,600 ft) and Materkuh with a height of 3,940 metres (12,930 ft), while Gansser in 1964 indicated a summit height of 4,050 metres (13,290 ft).[24] Another report from 1931 claimed a summit height of 13,034 feet (3,973 m),[25] a report in 1976 4,032 metres (13,228 ft),[26] and a map in 2004 of 4,061 metres (13,323 ft).[27] These summits rise up to 2,000 metres (6,600 ft) around the surrounding plains.[12] Narkuh has two craters, the northern of which is lower and is the source of more lava flows than the southern.[22] The northwest Narkuh cone of Pleistocene age is highly eroded, while the southeastern Materkuh cone has fresh appearing lava flows and displays solfataric activity.[3][14] Materkuh has three principal craters,[28] the eastern side of the eastern crater has also been affected by erosion.[22] 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 12 kilometres (7.5 mi).[28] In general, thick andesitic lava flows cover Materkuh.[29] Percy Sykes in 1893 and 1914 described a summit plateau with a surface of 370 metres (400 yd), at the side of which lay two summits Ziaret Kuh ("Hill of Sacrifice", where pilgrims sacrificed goats) and Madar Kuh ("Mother Hill", containing fumaroles according to the 1893 report).[2][5] Fumarolic alteration of the summit area has generated sulfur and clay deposits which appear like a snowcap.[24] One report in 1893 indicated that the summit area of the volcano is covered with ash from 3,400 metres (11,000 ft) upwards.[5]

There is evidence of southeastward migration of the craters of Taftan, with Anjerk and Sardarya being more westerly vents.[30] These preceding centres have left andesitic lava flows that are partially dissected and agglomerates.[22] A magma chamber may lie beneath the volcano.[31] The bulk of the volcano is formed by lava flows, along with volcaniclastic rocks,[8] with dacites and pyroclastics lying on top of the Cretaceous-Eocene basement.[32] 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 30 kilometres (19 mi) away from the central vents.[26] Several fans of pyroclastic material, cemented by andesitic tuffs, surround the base of Taftan.[33] Ignimbrites and pyroclastic flows are also present, including breccias, nuee ardentes and tuffs.[23] Volcanic rocks cover a surface of 1,050 square kilometres (410 sq mi).[19] The table mountain Takht-i-Rostam 25 kilometres (16 mi) south of Taftan may be the remnant of a basalt extrusion, but it doesn't appear to be related to Taftan.[34]

Taftan is the highest mountain in southeast Iran.[7] The topography is overall steep.[35] Deep valleys with U and V shapes have developed on Taftan, the volcano has a strongly eroded appearance.[14] One of these valleys, Tamindan, may be the Damindan valley in the Avesta.[36] One series of ignimbrites surrounding Taftan which reaches thicknesses of 50 metres (160 ft) may be 2 million years old.[37]

Composition[edit]

Taftan has erupted rocks ranging from basaltic andesite to dacite. The dominant rocks is andesite, with SiO
2
ranging from 49.8 to 63.5%.[38] Grey andesites form the youngest rocks on the main summit and contain chlorite schist and biotite gneiss inclusions.[33] The magma of Taftan volcano is very oxidized, as can be inferred from the composition of ignimbrites and the fumarole gases.[39]

The lavas are porphyric. Mineral components include biotite, clinopyroxene, hornblende, orthopyroxene, plagioclase and quartz. Other components are chalcopyrite, hematite, ilmenite, magnetite and pyrite.[14] Complex phenocryst assemblages found in a sample indicate that the magma formation is a complex process.[24] Taftan rocks overall are K-rich calc-alkaline,[23] of subalkaline affinity.[38] The magma that formed these rocks was influenced by crystal fractionation and mixing processes.[23] Its composition has characteristics of volcanic arc magmas.[40] Crustal materials were involved in the formation of the magma,[14] with Sr isotope data indicating crustal assimilation.[18]

Rocks and pyroclastics are affected by the fumarolic activity.[39] Carbonates and opal and white covers of possibly aluminum sulfate and calcium sulfate have been formed. Gypsum formed from 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.[41] Minerals formed by alteration processes include alunite, calcite, cristobalite, illite, jarosite, kaolinite, pyrophyllite, quartz, smectite, sulfur and tridymite.[42] Some epithermal mineralizations have been identified around Taftan.[40] Other secondary factors at Taftan include lahars.[23]

Climate[edit]

The climate at Taftan features cold winters which can be accompanied by snowfall when temperatures drop below freezing between December and February, and hot summers with temperatures during July and August exceeding 30 °C (86 °F).[14]

Taftan is located in an arid area but itself it has more precipitation, thus being a supply of water to the area.[43] Average precipitation is 150 millimetres (5.9 in) per year.[35]

Eruptive history[edit]

About five different eruption stages have been found at Taftan volcano.[8] Activity first involved lava and pyroclastics of dacitic to rhyodacitic composition. Later, upper Pliocene lavas were erupted along with agglomerates. These can be found up to 10 kilometres (6.2 mi) away from the cone.[12] Three phases have been dated at 6.95 ± 0.72 mya, 6.01 ± 0.15 mya and 0.71 ± 0.03 mya ago.[23] 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 in the present geological epoch.[5] 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 people around the volcano.[10]

The volcano in 1914 was described to be "belching out clouds of smoke".[2] A report in 1971 indicated the absence of historical activity.[34] Eruptions are recorded in 1902, 1970 and 1993. These eruptions were accompanied by earthquake activity.[44] During the eruption of 1902, strong smoking and a night time glow on the volcano were observed.[45] The eruption in 1993 involved a c. 60 metres (200 ft) long lava flow,[46] but it may have been a flow of molten sulfur.[14] The volcano is currently classified as dormant volcano.[29] Satellite imagery indicates that ground deformation occurs at Taftan.[47]

Fumarolic and geothermal activity[edit]

Taftan displays vigorous fumarolic activity, with high temperature vents found around the crater.[39] Fumaroles are found chiefly in the eastern and at the edge of the western crater, with minor fumaroles within the western crater, some minor craters and along the major lava flow.[28] These gas exhalations are known as "Dood" and they appear as yellow-white clouds with a strong smell. The vents they come from have the shape of fissures, cracks and crevices.[3] The larger fumaroles can reach diametres of 1 metre (3 ft 3 in).[33] Reportedly in 1897 the smell of the fumaroles was so strong as to unbearable close to the vents.[5] One report mentioned in a magazine of 1899 indicated the presence of seven steam vents at an altitude of 3,700 metres (12,000 ft), producing audible noise. Their steam plumes were visible at distances of 16–24 kilometres (10–15 mi),[1] later reporting indicated visibility to distances of 100 kilometres (62 mi).[9] Another report in 1999 found a 1.5 by 5 metres (4 ft 11 in × 16 ft 5 in) solfatara surrounded by clay and sulfur deposits that looked like a snowcap.[48] 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 c. 10 square metres (110 sq ft).[24] The name "Taftan" is derived from these exhalations, which look like the mountain is burning.[3]

The overall gas composition includes CO
2
, H
2
S
, SO
2
and water.[3] Sulfur is present in high quantities in fumarolic gases, which also contain arsenic. These gases are hence extremely acidic.[39] The fumaroles have altered rocks, forming highly colourful exposures especially on Taftan's eastern flank.[33] Salmiak and sulfur has been collected around fumaroles.[1] 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.[3]

Hot springs are found at Taftan, especially at over 3,000 metres (9,800 ft) of altitude.[35] An analysis of 5 springs in May 2012 indicated temperatures of 11–56 °C (52–133 °F) and flow rates of 0.5–11 litres per second (6.6–145.2 imp gal/min).[49] The waters are very acidic due to formation of H
2
SO
4
from magmatic gases.[50] The hot waters around Taftan contain large quantities of boron,[39] probably because the hydrothermal system of Taftan is young and receives input of host rock B.[51] They are influenced by the fumarolic gases,[39] as well as by volcanic rock composition. Some of the water in the area is juvenile,[43] with magmatic water forming up to 20% of the water.[31] Temperatures in the hydrothermal system are estimated to be 104–210 °C (219–410 °F) and 75–185 °C (167–365 °F).[52] 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 brines.[53] The geothermal area of Taftan is among the largest in the Makran zone of Iran,[54] it covers a surface area of 4,310 square kilometres (1,660 sq mi).[55] Mud pools are also found at Taftan.[56]

See also[edit]

References[edit]

  1. ^ a b c McMahon, C. A. (1 May 2009). "The Persian Volcano Koh-I-Taftan". Geological Magazine 6 (07): 336. doi:10.1017/S0016756800142359. 
  2. ^ a b c Sykes, P.N. (April 1914). "Twenty years' travel in Persia". Scottish Geographical Magazine 30 (4): 175–176. doi:10.1080/14702541408555166. 
  3. ^ a b c d e f g h Kiyanoosh Kiyani Haftlang; Kiyānūsh Kiyānī Haft Lang (2003). The Book of Iran: A Survey of the Geography of Iran. Alhoda UK. pp. 15–16. ISBN 978-964-94491-3-5. 
  4. ^ Sykes, P. Molesworth (December 1897). "Recent Journeys in Persia". The Geographical Journal 10 (6): 568. doi:10.2307/1774906. 
  5. ^ a b c d e McMahon, C. A.; McMahon, A. H. (1 February 1897). "Notes on some Volcanic and other Rocks, which occur near the Baluchistan-Afghan Frontier, between Chaman and Persia". Quarterly Journal of the Geological Society 53 (1-4): 292–293. doi:10.1144/GSL.JGS.1897.053.01-04.23. 
  6. ^ a b c "Iran - 54 Mountain Summits with Prominence of 1,500 meters or greater". Peaklist.org. Retrieved 2013-02-10. 
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  8. ^ a b c d Biabangard, H.A.; Moradian, Abas (2009). "VOLCANOSTRATIGHRAPHY AND DIFFERENT STAGES OF EXPLOSIVE OF TAFTAN VOLCANO". Geosciences 18 (72): 73–82. Retrieved 13 July 2016. 
  9. ^ a b Gansser, 1971, p.320
  10. ^ a b Gansser, 1971, p.321
  11. ^ a b Gansser, 1971, p.322
  12. ^ a b c d e Sadeghi et al., 2015, p.2
  13. ^ a b Perello, J.; Razique, A.; Schloderer, J.; Asad-ur-Rehman (1 December 2008). "The Chagai Porphyry Copper Belt, Baluchistan Province, Pakistan". Economic Geology 103 (8): 1586. doi:10.2113/gsecongeo.103.8.1583. 
  14. ^ a b c d e f g h Shakeri et al., 2008, p.830
  15. ^ Saadat et al., 2011, p.608
  16. ^ Sadeghi et al., 2015, p.1
  17. ^ Sadeghi et al., 2015, p.5
  18. ^ a b Saadat et al., 2011, p.617
  19. ^ a b Gansser, 1971, p.324
  20. ^ Kwan-Nang, Pang; Sun-Lin, Chung; Zarrinkoub, Mohammad H.; Han-Yi, Chiu; Xian-Hua, Li (May 2014). "Age and geochemical constraints on the Makran arc magmatism, Iran". The SAO/NASA Astrophysics Data System. Vienna: EGU General Assembly 2014,. Retrieved 13 July 2016. 
  21. ^ Pang, Kwan-Nang; Chung, Sun-Lin; Zarrinkoub, Mohammad Hossein; Chiu, Han-Yi; Li, Xian-Hua (June 2014). "On the magmatic record of the Makran arc, southeastern Iran: Insights from zircon U-Pb geochronology and bulk-rock geochemistry". Geochemistry, Geophysics, Geosystems 15 (6): 2161. doi:10.1002/2014GC005262. 
  22. ^ a b c d Gansser, 1971, p.325
  23. ^ a b c d e f Biabangard, H.; Moradian, A. (April 2008). "The geology of Mount Taftan stratovolcano, southeast of Iran". Nuovo Cimento della Societa Italiana di Fisica. C, Geophysics and Space Physics (2): 119–134. doi:10.1393/ncc/i2008-10295-3. Retrieved 13 July 2016. 
  24. ^ a b c d Wunderman, Richard (2004). "Report on Taftan (Iran)". Bulletin of the Global Volcanism Network 29 (10). doi:10.5479/si.GVP.BGVN200410-232050. 
  25. ^ Skrine, 1931, p.321
  26. ^ a b Shearman, D. J.; Walker, G. P. L.; Booth, B.; Falcon, N. L. (November 1976). "The Geological Evolution of Southern Iran: The Report of the Iranian Makran Expedition". The Geographical Journal 142 (3): 405. doi:10.2307/1795293. 
  27. ^ Ghazban, 2004, p.46
  28. ^ a b c Gansser, 1971, p.326
  29. ^ a b Biabangard and Moradian, 2008, p.357
  30. ^ Biabangard and Moradian, 2008, p.368. Note, the map clearly indicates southeastward migration.
  31. ^ a b Shakeri et al., 2008, p.835
  32. ^ Ghazban, 2004, p.45
  33. ^ a b c d Gansser, 1971, p.328
  34. ^ a b Gansser, 1971, p.329
  35. ^ a b c Shakeri et al., 2015, p.50
  36. ^ Skrine, 1931, p.322
  37. ^ Saadat, S.; Karimpour, M.H.; Stern, Ch. (2010). "Petrochemical Characteristics of Neogene and Quaternary Alkali Olivine Basalts from the Western Margin of the Lut Block, Eastern Iran" (PDF). Iranian Journal of Earth Sciences 2: 89. Retrieved 13 July 2016. 
  38. ^ a b Biabangard and Moradian, 2008, p.360
  39. ^ a b c d e f Mokhtari, Zahra; Ahmadi, Ali. "INVESTIGATION OF CHEMICAL COMPOSITION OF GAS EXHALATION AND POST VOLCANIC ACTIVITIES OF TAFTAN VOLCANO, SE IRAN". Researchgate. Geochemistry. Retrieved 13 July 2016. 
  40. ^ a b Richards, Jeremy P. (October 2015). "Tectonic, magmatic, and metallogenic evolution of the Tethyan orogen: From subduction to collision". Ore Geology Reviews 70: 332. doi:10.1016/j.oregeorev.2014.11.009. 
  41. ^ Ghazban, 2004, p.48
  42. ^ Ghazban, 2004, p.52
  43. ^ a b Biabangard, H.; Moradian, A.; Bavali, Y. (2009). "STUDY OF THE HYDROGEOCHEMISTRY OF TAFTAN VOLCANO'S MINERAL SPRINGS AND THEIR RELATION TO HARD-ROCK MASSES OF REGION". Geosciences 19 (73): 99–108. Retrieved 13 July 2016. 
  44. ^ Rezaeinahal, Bahar; Zare, Mehdi; Ghorashi, Manoochehr; Nozaiiem, Reza (2014). "REVIEW THE SEISMIC ACTIVITY AND THE SIGNS INDICATE THE VOLCANIC ACTIVITY IN TAFTAN VOLCANIC REGION". GEOGRAPHY AND DEVELOPMENT 11 (33): 131–138. Retrieved 13 July 2016. 
  45. ^ "Taftan". Global Volcanism Program. Smithsonian Institution. 
  46. ^ Venzke, Edward (1993). "Report on Taftan (Iran)". Bulletin of the Global Volcanism Network 18 (4). doi:10.5479/si.GVP.BGVN199304-232050. 
  47. ^ Shirzaei, M. (2012). "A satellite geodetic survey of spatiotemporal deformation of Iranian volcanos". The SAO/NASA Astrophysics Data System. EGU General Assembly 2012. Retrieved 13 July 2016. 
  48. ^ Wunderman, Richard (1999). "Report on Taftan (Iran)". Bulletin of the Global Volcanism Network 24 (10). doi:10.5479/si.GVP.BGVN199910-232050. 
  49. ^ Shakeri et al., 2015, p.51
  50. ^ Shakeri et al., 2015, p.56
  51. ^ Shakeri et al., 2008, p.833
  52. ^ Shakeri et al., 2008, p.834
  53. ^ Shakeri et al., 2008, p.831
  54. ^ Shakeri et al., 2015, p.49
  55. ^ Yousefi, Hossein; Ehara, Sachio; Noorollahi, Younes (January 2007). "GEOTHERMAL POTENTIAL SITE SELECTION USING GIS IN IRAN" (PDF). pangea.stanford.edu. Thirty-Second Workshop on Geothermal Reservoir Engineering. Retrieved 13 July 2016. 
  56. ^ Yousefi, Hossein; Noorollahi, Younes; Ehara, Sachio; Itoi, Ryuichi; Yousefi, Amin; Fujimitsu, Yasuhiro; Nishijima, Jun; Sasaki, Kyuro (June 2010). "Developing the geothermal resources map of Iran". Geothermics 39 (2): 146. doi:10.1016/j.geothermics.2009.11.001. 

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