Moho depth determination beneath the Zagros Mountains from 3D inversion of gravity data

  • Zahra B. Ashena
  • Vahid E. Ardestani
  • Antonio G. Camacho
  • Ali Dehghani
  • José Fernández
Original Paper


Due to its geological and economic importance, the Zagros Mountains have been investigated by many researchers during the last decades. Nevertheless, in spite of all the studies conducted on the region, there are still some controversial problems concerning the structure of the Zagros Mountains, including crustal depths, demanding more insights into understanding the crustal constraints of the region. Accordingly, we have conducted a gravity study to determine Moho depth map of the Zagros Mountains region, including its major structural domains from the coastal plain of the Persian Gulf to central Iran. The employed data are the densest and most accurate terrestrial gravity data set observed until now with the precision of 5 μGal and resolution of 5 arc-minute by 5 arc-minute. To image Moho depth variations, gravity inversion software GROWTH2.0 is used, proposing the possibility to model stratified structures by means of a semi-objective exploratory 3D inversion approach. The obtained results reveal the crustal thickness of ~ 30–35 km underneath the southwestern most Zagros Fold-Thrust Belt increasing northeastward to 48 km. The maximum Moho depth is estimated ~ 62 km below the Zagros Mountains belt along the Main Zagros Thrust. Northeast of the study area, an average crustal thickness of 46 km is computed beneath Urumieh–Dokhtar magmatic arc and central Iran.


Zagros Mountains Moho depth Gravity data 3D inversion 



The University of Tehran is acknowledged for the financial support of the first author’s sabbatical leave at AE Consejo Superior de Investigaciones Científicas, CSIC, during the period from March 2016 to August 2016. Research by JF and AGC has been supported by the Spanish Ministry of Economy and Competitiveness research project ESP2013-47780-557 C2-1-R. The Institute of Geosciences (CSIC-UCM) support is appreciated for hosting the first author as the guest researcher. The National Cartographic Center of Iran is also appreciated for providing the data. The first author also thanks Joaquín Escayo and Zeynab Golshadi for their support. It is a contribution to the Moncloa Campus of International Excellence.


  1. Agard P, Omrani J, Jolivet L, Mouthereau F (2005) Convergence history across Zagros (Iran): constraints from collisional and earlier deformation. Int J Earth Sci 94(3):401–419. CrossRefGoogle Scholar
  2. Alavi M (1994) Tectonics of the Zagros orogenic belt of Iran: new data and interpretations. Tectonophysics 229(3–4):211–238. CrossRefGoogle Scholar
  3. Alavi M (2007) Structures of the Zagros fold-thrust belt in Iran. Am J Sci 307(9):1064–1095. CrossRefGoogle Scholar
  4. Alinaghi A, Koulakov I, Thybo H (2007) Seismic tomographic imaging of P- and S-waves velocity perturbations in the upper mantle beneath Iran. Geophys J Int 169(3):1089–1102. CrossRefGoogle Scholar
  5. Al-Lazki AI, Sandvol E, Seber D, Barazangi M, Turkelli N, Mohamad R (2004) Pn tomographic imaging of mantle lid velocity and anisotropy at the junction of the Arabian, Eurasian and African plates. Geophys J Int 158(3):1024–1040. CrossRefGoogle Scholar
  6. Berberian M (1995) Master blind thrust faults hidden under the Zagros folds: active basement tectonics and surface morphotectonics. Tectonophysics 241(3-4):193–224. CrossRefGoogle Scholar
  7. Berberian M, King GCP (1981) Towards a paleogeography and tectonic evolution of Iran. Can J Earth Sci 18(2):210–265. CrossRefGoogle Scholar
  8. Bird P (1978) Finite element modeling of lithosphere deformation: the Zagros collision orogeny. Tectonophysics 50(2–3):307–336. CrossRefGoogle Scholar
  9. Camacho AG, Montesinos FG, Vieira R (2000) A 3-D gravity inversion by means of growing bodies. Geophysics 65(1):95–101. CrossRefGoogle Scholar
  10. Camacho AG, Montesinos FG, Vieira R (2002) A 3-D gravity inversion tool based on exploration of model possibilities. Comput Geosci 28:191–204CrossRefGoogle Scholar
  11. Camacho AG, Nunes JC, Ortiz E, França Z, Vieira R (2007) Gravimetric determination of an intrusive complex under the island of Faial (Azores): some methodological improvements. Geophys J Int 171(1):478–494. CrossRefGoogle Scholar
  12. Camacho AG, Fernández J, Gottsmann J (2011a) The 3-D gravity inversion package GROWTH2.0 and its application to Tenerife Island, Spain. Comput Geosci 37(4):621–633. CrossRefGoogle Scholar
  13. Camacho AG, Fernández J, Gottsmann J (2011b) A new gravity inversion method for multiple subhorizontal discontinuity interfaces and shallow basins. J Geophys Res 116(B2):B02413. CrossRefGoogle Scholar
  14. Dehghani G, Makris J (1984) The gravity field and crustal structure of Iran. Neues Jahrb Geol Palaontol Abh 168:215–229Google Scholar
  15. Falcon, N. L. (1974) Southern Iran: Zagros Mountains. Geological Society, London, Special Publications, 4(1), 199–211Google Scholar
  16. Hatzfeld D, Tatar M, Priestley K, Ghafory-Ashtyany M (2003) Seismological constraints on the crustal structure beneath the Zagros Mountain belt (Iran). Geophys J Int 155(2):403–410. CrossRefGoogle Scholar
  17. Jiménez-Munt I, Fernàndez M, Saura E, Vergés J, Garcia-Castellanos D (2012) 3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia—Eurasia collision (Iran). Geophys J Int 190(3):1311–1324. CrossRefGoogle Scholar
  18. Kaviani A, Paul A, Bourova E, Hatzfeld D, Pedersen H, Mokhtari M (2007) A strong seismic velocity contrast in the shallow mantle across the Zagros collision zone (Iran). Geophys J Int 171(1):399–410. CrossRefGoogle Scholar
  19. Manaman NS, Shomali H (2010) Upper mantle S-velocity structure and Moho depth variations across Zagros belt, Arabian–Eurasian plate boundary. Phys Earth Planet Inter 180(1–2):92–103CrossRefGoogle Scholar
  20. McQuarrie N (2004) Crustal scale geometry of the Zagros fold-thrust belt, Iran. J Struct Geol 26(3):519–535. CrossRefGoogle Scholar
  21. Molinaro M, Leturmy P, Guézou J-C, Frizon de Lamotte D (2005) The structure and kinematics of the south-eastern Zagros fold-thrust belt, Iran: from thin-skinned to thick-skinned tectonics. Tectonics 24:TC3007CrossRefGoogle Scholar
  22. Motaghi K, Tatar M, Priestley K, Romanelli F, Doglioni C, Panza GF (2015) The deep structure of the Iranian plateau. Gondwana Res 28(1):407–418. CrossRefGoogle Scholar
  23. Motavalli-Anbaran S-H, Zeyen H, Brunet M-F, Ardestani VE (2011) Crustal and lithospheric structure of the Alborz Mountains, Iran, and surrounding areas from integrated geophysical modeling. Tectonics 30:TC5012CrossRefGoogle Scholar
  24. Nasrabadi A, Tatar M, Priestley K, Sepahvand MR (2008) Continental lithosphere structure beneath the Iranian Plateau, from analysis of receiver functions and surfaces waves dispersion, The 14thWorld Conference on Earthquake Engineering, Beijing, ChinaGoogle Scholar
  25. Ni J, Barazangi M (1986) Seismotectonics of the Zagros continental collision zone and a comparison with Himalayas. J Geophys Res 91(B8):8205–8218. CrossRefGoogle Scholar
  26. Oskooi B, Pedersen LB, Koyi HA (2013) Magnetotelluric signature for the Zagros collision. Geophys J Int 196(3):1299–1310. CrossRefGoogle Scholar
  27. Paul A, Kaviani A, Hatzfeld D, Vergne J, Mokhtari M (2006) Seismological evidence for crustal-scale thrusting in the Zagros mountain belt (Iran). Geophys J Int 166(1):227–237. CrossRefGoogle Scholar
  28. Paul A, Hatzfeld D, Kaviani A, Tatar M, Péquegnat C (2010) Seismic imaging of the lithospheric structure of the Zagros mountain belt (Iran). Geol Soc Lond Spec Publ 330(1):5–18. CrossRefGoogle Scholar
  29. Shomali ZH, Keshvari F, Hassanzadeh J, Mirzaei N (2011) Lithospheric structure beneath the Zagros collision zone resolved by non-linear teleseismic tomography. Geophys J Int 187(1):394–406. CrossRefGoogle Scholar
  30. Snyder DB, Barazangi M (1986) Deep crustal structure and flexure of the Arabian plate beneath the Zagros collisional mountain belt as inferred from gravity observations. Tectonics 5(3):361–373. CrossRefGoogle Scholar
  31. Talebian M, Jackson J (2004) A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran. Geophys J Int 156(3):506–526. CrossRefGoogle Scholar
  32. Tarantola A (1988) The inverse problem theory: methods for data fitting and model parameter estimation. Elsevier, Amsterdam 613 ppGoogle Scholar
  33. Tatar M, Hatzfeld D, Martinod J, Walpersdorf A, Ghafori-Ashtiany M, Ch’ery J (2002) The present-day deformation of the central Zagros from GPS measurements. Geophys Res Lett 29(19):1927–33-4. CrossRefGoogle Scholar
  34. Tunini L, Jiménez-Munt I, Fernàndez M, Vergés J, Villaseñor A (2015) Lithospheric mantle heterogeneities beneath the Zagros Mountains and the Iranian Plateau: a petrological-geophysical study. Geophys J Int 200(1):596–614. CrossRefGoogle Scholar

Copyright information

© Saudi Society for Geosciences 2018

Authors and Affiliations

  • Zahra B. Ashena
    • 1
  • Vahid E. Ardestani
    • 1
  • Antonio G. Camacho
    • 2
  • Ali Dehghani
    • 3
  • José Fernández
    • 2
  1. 1.Institue of GeophysicsUniversity of TehranTehranIran
  2. 2.Facultad C. MatemáticasInstitute of Geosciences (CSIC, UCM)MadridSpain
  3. 3.University of HamburgHamburgGermany

Personalised recommendations