Mineralogy and Petrology

, Volume 113, Issue 1, pp 135–154 | Cite as

Phase equilibria and P-T-t path of metapelitic rocks in SE-Hamedan, Sanandaj-Sirjan Zone, Iran

  • Shahryar MahmoudiEmail author
  • Ali-Akbar Baharifar
Original Paper


In the southeast of Hamedan, in the Sanandaj-Sirjan Zone of Iran, metamorphic rocks display different metamorphic assemblages formed during dynamothermal and contact metamorphic events. The isograds in metapelitic rocks vary across the region: in the south, the sequence is chlorite – biotite – garnet – staurolite, but in the east and southeast it is chlorite – garnet – biotite – andalusite – sillimanite. Based on microstructure, peak metamorphic conditions were the same for both Al2SiO5(ALS) bearing and Al2SiO5 free assemblages: 628 °C and 4.4 kbar for the sillimanite zone and 577 °C and 4.2 kbar for the staurolite zone. Pseudosections were constructed for two representative bulk rock compositions, in the Kamari area for ALS bearing rocks and in the Aliabad-Damagh area for ALS free rocks. Comparing pseudosections with the estimated P and T shows that the appearance of ALS polymorphs was controlled by the chemical composition of the parent rocks rather than variations in P and T. The P-T paths of both ALS-bearing and ALS-free sequences are similar and both follow an anticlockwise trend but the geothermal gradient is slightly higher for ALS-bearing schists. It is concluded that different zones in the area developed at the same time, during the same deformation phases, but under different geothermal gradients. Metamorphism of the Hamedan area occurred during the convergent orogeny and subduction of the Neo-Tethys in the Jurassic and was coeval with the main magmatic phases.


Metapelites P-T path Phase equilibrium Sanandaj-Sirjan Zone Hamedan Iran 



Careful reviews by Dr. Robin Offler and Dr. Hossein Azizi and journal editor Dr. William Guenthner and Editor-in-chief Dr. Maarten A.T.M. BROEKMANS greatly helped to improve this paper.


  1. Alavi M (1994) Tectonics of the Zagros orogenic belt of Iran: new data and interpretations. Tectonophysics 229(3):211–238Google Scholar
  2. Aliani F, Maanijou M, Sabouri Z, Sepahi AA (2012) Petrology, geochemistry and geotectonic environment of the Alvand intrusive complex, Hamadan, Iran. Chemie der Erde - Geochem 72(4):363–383Google Scholar
  3. Azizi H, Najari M, Asahara Y, Catlos EJ, Shimizu M, Yamamoto K (2015a) U–Pb zircon ages and geochemistry of Kangareh and Taghiabad mafic bodies in northern Sanandaj–Sirjan zone, Iran: evidence for intra-oceanic arc and back-arc tectonic regime in late Jurassic. Tectonophysics 660:47–64Google Scholar
  4. Azizi H, Zanjefili-Beiranvand M, Asahara Y (2015b) Zircon U–Pb ages and petrogenesis of a tonalite–trondhjemite–granodiorite (TTG) complex in the northern Sanandaj–Sirjan zone, Northwest Iran: evidence for late Jurassic arc–continent collision. Lithos 216–217:178–195Google Scholar
  5. Azor A, Ballèvre M (1997) Low-pressure metamorphism in the Sierra Albarrana area (Variscan belt, Iberian massif). J Petrol 38(1):35–64Google Scholar
  6. Baharifar A (1997) New perspective on petrogenesis of the regional metamorphic rocks of Hamadan area, Iran. M. Sc. Thesis (in Persian), Tarbiat Moallem University, Tehran, IranGoogle Scholar
  7. Baharifar A (2004) Petrology of metamorphic rocks in the Hamadan area, Ph. D thesis, Tarbiat Moallem University, Tehran, Iran. 218p.(in Persian)Google Scholar
  8. Baharifar A (2010) Fluid pressure and the lack of Chloritoid in Metapelites: implications from Hamadan area, Sanandaj-Sirjan zone, Iran. Geoscienses 19(76):135–140Google Scholar
  9. Baharifar A, Moinevaziri H, Bellon H, Piqué A (2004) The crystalline complexes of Hamadan (Sanandaj–Sirjan zone, western Iran): metasedimentary Mesozoic sequences affected by late cretaceous tectono-metamorphic and plutonic events. Compt Rendus Geosci 336(16):1443–1452Google Scholar
  10. Baldwin JA, Powell R, White RW, Štípská P (2015) Using calculated chemical potential relationships to account for replacement of kyanite by symplectite in high pressure granulites. J Metamorph Geol 33(3):311–330Google Scholar
  11. Berberian M, Alavi-Tehrani N (1977) Structural analyses of Hamadan metamorphic tectonites. Geological survey of Iran, report 40Geological survey of Iran. Report 40(1977):239–260Google Scholar
  12. Berberian M, King G (1981) Towards a paleogeography and tectonic evolution of Iran. Can J Earth Sci 18(2):210–265Google Scholar
  13. Brown M (1993) P–T–t evolution of orogenic belts and the causes of regional metamorphism. J Geol Soc 150(2):227–241Google Scholar
  14. Capitani CD, Petrakakis K (2010) The computation of equilibrium assemblage diagrams with Theriak/Domino software. Am Mineral 95(7):1006–1016Google Scholar
  15. Cesare B, Gómez-Pugnaire MT, Sánchez-Navas A, Grobety B (2002) Andalusite-sillimanite replacement (Mazarrón, SE Spain): a microstructural and TEM study. Am Mineral 87(4):433–444Google Scholar
  16. Chu X, Ague J (2013) Phase equilibria for graphitic metapelite including solution of CO2 in melt and cordierite: implications for dehydration, partial melting and graphite precipitation. J Metamorph Geol 31(8):843–862Google Scholar
  17. Connolly J (1995) Phase diagram methods for graphitic rocks and application to the system C− O− H− FeO− TiO2− SiO2. Contrib Mineral Petrol 119(1):94–116Google Scholar
  18. Connolly J, Cesare B (1993) C-O-H-S fluid composition and oxygen fugacity in graphitic metapelites. J Metamorph Geol 11(3):379–388Google Scholar
  19. Deer WA, Howie RA, Zussman J (1992) An introduction to the rock forming minerals. Longman. Burnt Mill, England, p 696Google Scholar
  20. Dymoke P, Sandiford M (1992) Phase relationships in Buchan facies series pelitic assemblages: calculations with application to andalusite-staurolite parageneses in the mount lofty ranges, South Australia. Contrib Mineral Petrol 110(1):121–132Google Scholar
  21. Essene E J (1989) Update on geologic thermobarometry. In: Daly JS, Cliff RA, Yardley BWD (eds) Evolution of metamorphic Belts. Geological Society Special Publication, London, p 43: 1–44Google Scholar
  22. Fergusson C, Nutman A, Mohajjel M, Bennett V (2016) The Sanandaj–Sirjan zone in the neo-Tethyan suture, western Iran: zircon U–Pb evidence of late Palaeozoic rifting of northern Gondwana and mid-Jurassic orogenesis. Gondwana Res 40:43–57Google Scholar
  23. Foster CT (1991) The role of biotite as a catalyst in reaction mechanisms that form sillimanite. Can Mineral 29(4):943–963Google Scholar
  24. Ganguly J, Dasgupta S, Cheng W, Neogi S (2000) Exhumation history of a section of the Sikkim Himalayas, India: records in the metamorphic mineral equilibria and compositional zoning of garnet. Earth Planet Sci Lett 183(3):471–486Google Scholar
  25. Ghasemi A, Talbot C (2006) A new tectonic scenario for the Sanandaj–Sirjan zone (Iran). J Asian Earth Sci 26(6):683–693Google Scholar
  26. Graessner T, Schenk V (1999) Low-pressure metamorphism of Palaeozoic pelites in the Aspromonte, southern Calabria: constraints for the thermal evolution in the Calabrian crustal cross-section during the Hercynian orogeny. J Metamorph Geol 17:157–172Google Scholar
  27. Grew ES, Locock AJ, Mills SJ, Galuskina IO, Galuskin EV, Hålenius U (2013) IMA report. Nomenclature of the garnet supergroup. Am Mineral 98:785–811Google Scholar
  28. Hassanzadeh J, Wernicke BP (2016) The Neotethyan Sanandaj-Sirjan zone of Iran as an archetype for passive margin - arc transitions. Tectonics 35:586–621Google Scholar
  29. Hodges K, Crowley P (1985) Error estimation and empirical geothermobarometry for pelitic systems. Am Mineral 70(7–8):702–709Google Scholar
  30. Hoisch TD (1990) Empirical calibration of six geobarometers for the mineral assemblage quartz+ muscovite+ biotite+ plagioclase+ garnet. Contrib Mineral Petrol 104(2):225–234Google Scholar
  31. Holdaway M (2000) Application of new experimental and garnet Margules data to the garnet-biotite geothermometer. Am Mineral 85(7–8):881–892Google Scholar
  32. Holdaway M (2001) Recalibration of the GASP geobarometer in light of recent garnet and plagioclase activity models and versions of the garnet-biotite geothermometer. Am Mineral 86(10):1117–1129Google Scholar
  33. Holland T, Powell R (1998) An internally consistent thermodynamic data set for phases of petrological interest. J Metamorph Geol 16(3):309–343Google Scholar
  34. Kerrick DM (1987) Fibrolite in contact aureoles of Donegal, Ireland. Am Mineral 72(3–4):240–254Google Scholar
  35. Laird J (1988) Chlorites; metamorphic petrology. Rev Mineral Geochem 19(1):405–453Google Scholar
  36. Lancaster PJ, Baxter EF, Ague JJ, Breeding CM, Owens TL (2008) Synchronous peak Barrovian metamorphism driven by syn-orogenic magmatism and fluid flow in southern Connecticut, USA. J Metamorph Geol 26(5):527–538Google Scholar
  37. Le Maitre RW, Streckeisen A, Zanettin B, Le Bas MJ, Bonin B, Bateman P, Bellieni G, Dudek A, Efremova S, Keller J, Lameyre J, Sabine PA, Schmid R, Sørensen H, Wooley AR (2002) Igneous rocks, a classification and glossary of terms. (recommendations of the international union of geological sciences subcommission on the systematics of igneous rocks). Cambridge University Press, Cambridge, p 236Google Scholar
  38. Lux D, DeYoreo J, Guldotti C, Decker E (1986) Role of plutonism in low-pressure metamorphic belt formation. Nature 323(6091):794–797Google Scholar
  39. Mahmoudi S, Corfu F, Masoudi F, Mehrabi B, Mohajjel M (2011) U–Pb dating and emplacement history of granitoid plutons in the northern Sanandaj–Sirjan zone, Iran. J Asian Earth Sci 41(3):238–249Google Scholar
  40. Mehdipour-Ghazi j, Moazzen M (2015) Geodynamic evolution of the Sanandaj-Sirjan zone, Zagros Orogen, Iran. Turk J Earth Sci 24(5):513–528Google Scholar
  41. Mohajel M, Valizadeh MV, Moghadam F (2006) Deformation analysis of Aliabad-e-Damagh mylonites granites and the significance of its shear zone on the tectonic interpretation of Hamadan region. J Sci, Tehran Uni 32(2):91–104Google Scholar
  42. Mohajjel M, Fergusson CL, Sahandi MR (2003) Cretaceous–tertiary convergence and continental collision, Sanandaj–Sirjan zone, western Iran. J Asian Earth Sci 21(4):397–412Google Scholar
  43. Mohajjel M, Baharifar A, Moinevaziri H, Nozaem R (2006) Deformation history, micro-structure and PTt path in ALS-bearing schists, Southeast Hamadan, Sanandaj-Sirjan zone, Iran. J Geol Soc Iran 1:11–19Google Scholar
  44. Moynihan D, Pattison D (2013) An automated method for the calculation of P–T paths from garnet zoning, with application to metapelitic schist from the Kootenay arc, British Columbia, Canada. J Metamorph Geol 31(5):525–548Google Scholar
  45. Nutman AP, Mohajjel M, Bennett VC, Fergusson CL (2013) Gondwanan Eoarchean–Neoproterozoic ancient crustal material in Iran and Turkey: zircon U–Pb–Hf isotopic evidence 1. Can J Earth Sci 51(3):272–285Google Scholar
  46. Ohmoto H, Kerrick D (1977) Devolatilization equilibria in graphitic systems. Am J Sci 277(8):1013–1044Google Scholar
  47. Palin RM, Weller OM, Waters DJ, Dyck B (2016) Quantifying geological uncertainty in metamorphic phase equilibria modelling; a Monte Carlo assessment and implications for tectonic interpretations. Geosci Front 7(4):591–607Google Scholar
  48. Pattison D (1992) Stability ofandalusite and sillimanite and the Al2Si05 triple point: constraints from the Ballachulish aureole, Scotland. J Geol 100:423–446Google Scholar
  49. Pattison DR (2006) The fate of graphite in prograde metamorphism of pelites: an example from the Ballachulish aureole, Scotland. Lithos 88(1):85–99Google Scholar
  50. Pattison DR, DeBuhr CL (2015) Petrology of metapelites in the Bugaboo aureole, British Columbia, Canada. J Metamorph Geol 33(5):437–462Google Scholar
  51. Pattison DR, De Capitani C, Gaidies F (2011) Petrological consequences of variations in metamorphic reaction affinity. J Metamorph Geol 29(9):953–977Google Scholar
  52. Pouchou J, Pichoir F (1985) In: Armstrong JT (ed) PAP’j (rZ) procedure for improved quantitative microanalysis. Pp. 104À106 in: Microbeam Analysis. San Francisco Press, San FranciscoGoogle Scholar
  53. Powell CM (1979) A morphological classification of rock cleavage. Tectonophysics 58(1–2):21–34Google Scholar
  54. Powell R, Holland T (2008) On thermobarometry. J Metamorph Geol 26(2):155–179Google Scholar
  55. Reche J, Martinez FJ (1996) GPT: an excel spreadsheet for thermobarometric calculations in metapelitic rocks. Comput Geosci 22(7):775–784Google Scholar
  56. Saki A, Moazzen M, Baharifar AA (2012) Migmatite microstructures and partial melting of Hamadan metapelitic rocks, Alvand contact aureole, western Iran. Int Geol Rev 54(11):1229–1240Google Scholar
  57. Sandiford M, Powell R (1991) Some remarks on high-temperature—low-pressure metamorphism in convergent orogens. J Metamorph Geol 9(3):333–340Google Scholar
  58. Sandiford M, Martin N Zhou S, Fraser G (1991) Mechanical consequences of granite emplacement during high-T, low-P metamorphism and the origin of “anticlockwise”PT paths. Earth Planet Sci Lett 107(1):164–172Google Scholar
  59. Sepahi A, Whitney D, Baharifar A (2004) Petrogenesis of andalusite–kyanite–sillimanite veins and host rocks, Sanandaj-Sirjan metamorphic belt, Hamadan, Iran. J Metamorph Geol 22(2):119–134Google Scholar
  60. Shahbazi H, Siebel W, Pourmoafee M, Ghorbani M, Sepahi AA, Shang CK, Vousoughi Abedini M (2010) Geochemistry and U–Pb zircon geochronology of the Alvand plutonic complex in Sanandaj–Sirjan zone (Iran): new evidence for Jurassic magmatism. J Asian Earth Sci 39(6):668–683Google Scholar
  61. Shakerardakani F, Neubauer F, Masoudi F, Mehrabi B, Liu X, Dong Y, Mohajjel M, Monfaredi B, Friedl G (2015) Panafrican basement and Mesozoic gabbro in the Zagros orogenic belt in the Dorud–Azna region (NW Iran): laser-ablation ICP–MS zircon ages and geochemistry. Tectonophysics 647:146–171Google Scholar
  62. Spear FS, Pattison DR (2017) The implications of overstepping for metamorphic assemblage diagrams (MADs). Chem Geol 457:38–46Google Scholar
  63. Stocklin J (1968) Structural history and tectonics of Iran: a review. AAPG Bull 52(7):1229–1258Google Scholar
  64. Tirone M, Ganguly J (2010) Garnet compositions as recorders of P–T–t history of metamorphic rocks. Gondwana Res 18(1):138–146Google Scholar
  65. Todd CS (1998) Limits on the precision of geobarometry at low grossular and anorthite content. Am Mineral 83(12):1161–1167Google Scholar
  66. Tracy RJ (1982) Compositional zoning and inclusions in metamorphic minerals. Rev Mineral Geochem 10(1):355–397Google Scholar
  67. Wei C, Clarke G, Tian W, Qiu L (2007) Transition of metamorphic series from the Kyanite-to andalusite-types in the Altai orogen, Xinjiang, China: evidence from petrography and calculated KMnFMASH and KFMASH phase relations. Lithos 96(3):353–374Google Scholar
  68. White R, Powell R, Holland T (2007) Progress relating to calculation of partial melting equilibria for metapelites. J Metamorph Geol 25(5):511–527Google Scholar
  69. Whitney DL (1996) Garnets as open systems during regional metamorphism. Geology 24(2):147–150Google Scholar
  70. Whitney DL, Evans BW (2010) Abbreviations for names of rock-forming minerals. Am Mineral 95(1):185–187Google Scholar
  71. Whitney D, Mechum T, Kuehner S, Dilek Y (1996a) Progressive metamorphism of pelitic rocks from protolith to granulite facies, Dutchess County, New York, USA: constraints on the timing of fluid infiltration during regional metamorphism. J Metamorph Geol 14(2):163–181Google Scholar
  72. Whitney DL, Mechum TA, Dilek Y, Kuehner SM (1996b) Modification of garnet by fluid infiltration during regional metamorphism in garnet through sillimanite-zone rocks, Dutchess County, New York. Am Mineral 81(5–6):696–705Google Scholar
  73. Will T, Okrusch M, Gruner B (2004) Barrovian and Buchan type metamorphism in the pan-African Kaoko belt, Namibia: implications for its geotectonic position within the framework of Western Gondwana. S Afr J Geol 107(3):431–454Google Scholar

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© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Faculty of Earth SciencesGeochemistry Department, Kharazmi UniversityTehranIran
  2. 2.Geology DepartmentPayam-e-Noor University (PNU)TehranIran

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