Article | Published:

Forced subduction initiation recorded in the sole and crust of the Semail Ophiolite of Oman

Nature Geosciencevolume 11pages688695 (2018) | Download Citation


Subduction zones are unique to Earth and fundamental in its evolution, yet we still know little about the causes and mechanisms of their initiation. Numerical models show that far-field forcing may cause subduction initiation at weak pre-existing structures, while inferences from modern subduction zones suggest initiation through spontaneous lithospheric gravitational collapse. For both endmembers, the timing of subduction inception corresponds with initial lower plate burial, whereas coeval or delayed extension in the upper plate are diagnostic of spontaneous or forced subduction initiation, respectively. In modern systems, the earliest extension-related upper plate rocks are found in forearcs, but lower plate rocks that recorded initial burial have been subducted and are inaccessible. Here, we investigate a fossil system, the archetypal Semail Ophiolite of Oman, which exposes both lower and upper plate relics of incipient subduction stages. We show with Lu–Hf and U–Pb geochronology of the lower and upper plate material that initial burial of the lower plate occurred before 104 million years ago, predating upper plate extension and the formation of Semail oceanic crust by at least 8 Myr. Such a time lag reveals far-field forced subduction initiation and provides unequivocal, direct evidence for a subduction initiation mechanism in the geological record.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


  1. 1.

    Lithgow-Bertelloni, C. Encyclopedia of Marine Geosciences (eds Harff, J., Meschede, M., Petersen, S. & Thiede, J.) 193–196 (Springer, Dordrecht, 2016).

  2. 2.

    Stern, R. J. & Gerya, T. Subduction initiation in nature and models: a review. Tectonophysics (2017).

  3. 3.

    Stern, R. J. Subduction initiation: spontaneous and induced. Earth Planet. Sci. Lett. 226, 275–292 (2004).

  4. 4.

    Gurnis, M., Hall, C. & Lavier, L. Evolving force balance during incipient subduction. Geochem. Geophys. Geosyst. 5, Q07001 (2004).

  5. 5.

    Hall, C. E., Gurnis, M., Sdrolias, M., Lavier, L. L. & Mueller, R. D. Catastrophic initiation of subduction following forced convergence across fracture zones. Earth Planet. Sci. Lett. 212, 15–30 (2003).

  6. 6.

    Leng, W., Gurnis, M. & Asimow, P. From basalts to boninites: the geodynamics of volcanic expression during induced subduction initiation. Lithosphere 4, 511–523 (2012).

  7. 7.

    Stern, R. J. & Bloomer, S. H. Subduction zone infancy: examples from the Eocene Izu–Bonin–Mariana and Jurassic California arcs. Geol. Soc. Am. Bull. 104, 1621–1636 (1992).

  8. 8.

    Stern, R. J., Reagan, M., Ishizuka, O., Ohara, Y. & Whattam, S. To understand subduction initiation, study forearc crust: to understand forearc crust, study ophiolites. Lithosphere 4, 469–483 (2012).

  9. 9.

    Van Hinsbergen, D. J. et al. Dynamics of intraoceanic subduction initiation: 2. Suprasubduction zone ophiolite formation and metamorphic sole exhumation in context of absolute plate motions. Geochem. Geophys. Geosyst. 16, 1771–1785 (2015).

  10. 10.

    Reagan, M. K. et al. Subduction initiation and ophiolite crust: new insights from IODP drilling. Int. Geol. Rev. 59, 1439–1450 (2017).

  11. 11.

    Arculus, R. J. et al. A record of spontaneous subduction initiation in the Izu–Bonin–Mariana Arc. Nat. Geosci. 8, 728–733 (2015).

  12. 12.

    Faccenna, C., Becker, T. W., Lallemand, S. & Steinberger, B. On the role of slab pull in the Cenozoic motion of the Pacific plate. Geophys. Res. Lett. 39, L03305 (2012).

  13. 13.

    Pearce, J. A., Lippard, S. J. & Roberts, S. Characteristics and tectonic significance of supra-subduction zone ophiolites. Geol. Soc. Spec. Publ. 16, 74–94 (1984).

  14. 14.

    Dilek, Y. & Furnes, H. Ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere. Geol. Soc. Am. Bull. 123, 387–411 (2011).

  15. 15.

    Dewey, J. F. Ophiolite obduction. Tectonophysics 31, 93–120 (1976).

  16. 16.

    Jamieson, R. A. PT paths from high temperature shear zones beneath ophiolites. J. Metamorph. Geol. 4, 3–22 (1986).

  17. 17.

    Spray, J. G. Possible causes and consequences of upper mantle decoupling and ophiolite displacement. Geol. Soc. Lond. Spec. Publ. 13, 255–268 (1984).

  18. 18.

    Wakabayashi, J. & Dilek, Y. Spatial and temporal relationships between ophiolites and their metamorphic soles: a test of models of forearc ophiolite genesis. Geol. Soc. Am. Spec. Pap. 349, 53–64 (2000).

  19. 19.

    Williams, H. & Smyth, W. R. Metamorphic aureoles beneath ophiolite suites and alpine peridotites: tectonic implications with west Newfoundland examples. Am. J. Sci. 273, 594–621 (1973).

  20. 20.

    Agard, P. et al. Plate interface rheological switches during subduction infancy: control on slab penetration and metamorphic sole formation. Earth Planet. Sci. Lett. 451, 208–220 (2016).

  21. 21.

    Soret, M., Agard, P., Dubacq, B., Plunder, A. & Yamato, P. Petrological evidence for stepwise accretion of metamorphic soles during subduction infancy (Semail Ophiolite, Oman and UAE). J. Metamorph. Geol. 35, 1051–1080 (2017).

  22. 22.

    Pattison, D. R. M. Petrogenetic significance of orthopyroxene‐free garnet + clinopyroxene + plagioclase ± quartz‐bearing metabasites with respect to the amphibolite and granulite facies. J. Metamorph. Geol. 21, 21–34 (2003).

  23. 23.

    Palin, R. M. et al. High-grade metamorphism and partial melting of basic and intermediate rocks. J. Metamorph. Geol. 34, 871–892 (2016).

  24. 24.

    Peacock, S. M., Rushmer, T. & Thompson, A. B. Partial melting of subducting oceanic crust. Earth Planet. Sci. Lett. 121, 227–244 (1994).

  25. 25.

    Rioux, M. et al. Rapid crustal accretion and magma assimilation in the Oman-U.A.E. ophiolite: High precision U–Pb zircon geochronology of the gabbroic crust. J. Geophys. Res. Solid Earth 117, B07201 (2012).

  26. 26.

    Rioux, M. et al. Tectonic development of the Samail Ophiolite: high-precision U–Pb zircon geochronology and Sm–Nd isotopic constraints on crustal growth and emplacement. J. Geophys. Res. Solid Earth 118, 2085–2101 (2013).

  27. 27.

    Hacker, B. R. Rapid emplacement of young oceanic lithosphere: argon geochronology of the Oman Ophiolite. Science 265, 1563–1565 (1994).

  28. 28.

    Hacker, B. R., Mosenfelder, J. L. & Gnos, E. Rapid emplacement of the Oman Ophiolite: thermal and geochronologic constraints. Tectonics 15, 1230–1247 (1996).

  29. 29.

    Rioux, M. et al. Synchronous formation of the metamorphic sole and igneous crust of the Semail Ophiolite: new constraints on the tectonic evolution during ophiolite formation from high-precision U–Pb zircon geochronology. Earth Planet. Sci. Lett. 451, 185–195 (2016).

  30. 30.

    Warren, C. J., Parrish, R. R., Waters, D. J. & Searle, M. P. Dating the geologic history of Oman’s Semail Ophiolite: insights from U/Pb geochronology. Contrib. Mineral. Petrol. 150, 403–422 (2005).

  31. 31.

    Yakymchuk, C., Clark, C. & White, R. W. Phase relations, reaction sequences and petrochronology. Rev. Mineral. Geochem. 83, 13–53 (2017).

  32. 32.

    Baxter, E. F. & Scherer, E. E. Garnet geochronology: timekeeper of tectonometamorphic processes. Elements 9, 433–438 (2013).

  33. 33.

    Scherer, E. E., Cameron, K. L. & Blichert-Toft, J. Lu–Hf garnet geochronology: closure temperature relative to the Sm–Nd system and the effects of trace mineral inclusions. Geochim. Cosmochim. Acta 64, 3413–3432 (2000).

  34. 34.

    Smit, M. A., Scherer, E. E. & Mezger, K. Lu–Hf and Sm–Nd garnet geochronology: chronometric closure and implications for dating petrological processes. Earth Planet. Sci. Lett. 381, 222–233 (2013).

  35. 35.

    Anczkiewicz, R. et al. Lu–Hf geochronology and trace element distribution in garnet: implications for uplift and exhumation of ultra-high pressure granulites in the Sudetes, SW Poland. Lithos 95, 363–380 (2007).

  36. 36.

    Hacker, B. R. & Gnos, E. The conundrum of Samail: explaining the metamorphic history. Tectonophysics 279, 215–226 (1997).

  37. 37.

    Searle, M. P., Warren, C. J., Waters, D. J. & Parrish, R. R. Structural evolution, metamorphism and restoration of the Arabian continental margin, Saih Hatat region, Oman Mountains. J. Struct. Geol. 26, 451–473 (2004).

  38. 38.

    Nicolas, A., Boudier, F., Ildefonse, B. & Ball, E. Accretion of Oman and United Arab Emirates ophiolite—discussion of a new structural map. Mar. Geophys. Res. 21, 147–180 (2000).

  39. 39.

    Boudier, F., Ceuleneer, G. & Nicolas, A. Shear zones, thrusts and related magmatism in the Oman Ophiolite: initiation of thrusting on an oceanic ridge. Tectonophysics 151, 275–296 (1988).

  40. 40.

    Ishikawa, T., Nagaishi, K. & Umino, S. Boninitic volcanism in the Oman Ophiolite: implications for thermal condition during transition from spreading ridge to arc. Geology 30, 899–902 (2002).

  41. 41.

    MacLeod, C. J., Lissenberg, L. & Bibby, L. E. “Moist MORB” axial magmatism in the Oman Ophiolite: the evidence against a mid-ocean ridge origin. Geology 41, 459–462 (2013).

  42. 42.

    Whattam, S. A. & Stern, R. J. The “subduction initiation rule”: a key for linking ophiolites, intra-oceanic fore-arcs, and subduction initiation. Contrib. Mineral. Petrol. 162, 1031–1045 (2011).

  43. 43.

    Agard, P., Jolivet, L., Vrielynck, B., Burov, E. & Monié, P. Plate acceleration: the obduction trigger? Earth Planet. Sci. Lett. 258, 428–441 (2007).

  44. 44.

    Duretz, T. et al. Thermo-mechanical modeling of the obduction process based on the Oman Ophiolite case. Gondwana Res. 32, 1–10 (2016).

  45. 45.

    Cowan, R. J., Searle, M. P. & Waters, D. J. Structure of the metamorphic sole to the Oman Ophiolite, Sumeini Window and Wadi Tayyin: implications for ophiolite obduction processes. Geol. Soc. Lond. Spec. Publ. 392, 155–175 (2014).

  46. 46.

    Gnos, E. Peak metamorphic conditions of garnet amphibolites beneath the Semail Ophiolite: implications for an inverted pressure gradient. Int. Geol. Rev. 40, 281–304 (1998).

  47. 47.

    Rioux, M., Bowring, S., Cheadle, M. & John, B. Evidence for initial excess 231Pa in mid-ocean ridge zircons. Chem. Geol. 397, 143–156 (2015).

  48. 48.

    Liu, J., Bohlen, S. R. & Ernst, W. G. Stability of hydrous phases in subducting oceanic crust. Earth Planet. Sci. Lett. 143, 161–171 (1996).

  49. 49.

    Bloch, E., Ganguly, J., Hervig, R. & Cheng, W. 176Lu–176Hf geochronology of garnet I: experimental determination of the diffusion kinetics of Lu3+ and Hf4+ in garnet, closure temperatures and geochronological implications. Contrib. Mineral. Petrol. 169, 12 (2015).

  50. 50.

    Ishikawa, T., Fujisawa, S., Nagaishi, K. & Fujisawa, T. Trace element characteristics of the fluid liberated from amphibolite-facies slab: inference from the metamorphic sole beneath the Oman Ophiolite and implication for boninite genesis. Earth Planet. Sci. Lett. 240, 355–377 (2005).

  51. 51.

    Sun, S.-s. & McDonough, W. F. Chemical and isotopic systematics of oceanic basalts: implications for mantle compositions and processes. Geol. Soc. Spec. Publ. 42, 313–345 (1989).

  52. 52.

    Jarosewich, E., Nelen, J. A. & Norberg, J. A. Reference samples for electronmicroprobe analysis. Geostand. Newslett. 4, 43–47 (1980).

  53. 53.

    Pouchou, J.-L. & Pichoir, F. in Electron Probe Quantification (eds Heinrich, K. & Newbury, D.) 31 75 (Springer, New York, 1991).

  54. 54.

    Jochum, K. P. et al. GeoReM: a new geochemical database for reference materials and isotopic standards. Geostand. Geoanal. Res. 29, 333–338 (2005).

  55. 55.

    Paton, C., Hellstrom, J., Paul, B., Woodhead, J. & Hergt, J. Iolite: freeware for the visualisation and processing of mass spectrometric data. J. Anal. Atom. Spectrom. 26, 2508–2518 (2011).

  56. 56.

    Münker, C., Weyer, S., Scherer, E. E. & Mezger, K. Separation of high field strength elements (Nb, Ta, Zr, Hf) and Lu from rock samples for MS-ICPMS measurements. Geochem. Geophys. Geosyst. 2, 2001GC000183 (2001).

  57. 57.

    Blichert-Toft, J., Boyet, M., Télouk, P. & Albarède, F. 147Sm–143Nd and 176Lu–176Hf in eucrites and the differentiation of the HED parent body. Earth Planet. Sci. Lett. 204, 167–181 (2002).

  58. 58.

    Blichert-Toft, J., Chauvel, C. & Albarede, F. Separation of Hf and Lu for high precision isotope analysis of rock samples by magnetic sector-multiple collector ICP-MS. Contrib. Mineral. Petrol. 127, 248–260 (1997).

  59. 59.

    Bizzarro, M., Baker, J. A. & Ulfbeck, D. A new digestion and chemical separation technique for rapid and highly reproducible determination of Lu/Hf and Hf isotope ratios in geological materials by MC-ICP-MS. Geostand. Geoanal. Res. 27, 133–145 (2003).

  60. 60.

    Ludwig, K. R. Isoplot 4.1. A Geochronological Toolkit for Microsoft Excel (Berkeley Geochronology Center, 2009).

  61. 61.

    Scherer, E. E., Mezger, K. & Münker, C. The 176Lu decay constant discrepancy: terrestrial samples vs. meteorites. Meteorit. Planet. Sci. 38, A136 (2003).

  62. 62.

    Söderlund, U., Patchett, P. J., Vervoort, J. D. & Isachsen, C. E. The 176Lu decay constant determined by Lu–Hf and U–Pb isotope systematics of Precambrian mafic intrusions. Earth Planet. Sci. Lett. 219, 311–324 (2004).

  63. 63.

    Mattinson, J. M. Zircon U–Pb chemical abrasion (“CA-TIMS”) method: combined annealing and multi-step partial dissolution analysis for improved precision and accuracy of zircon ages. Chem. Geol. 220, 47–66 (2005).

  64. 64.

    Mattinson, J. M. Analysis of the relative decay constants of 235U and 238U by multi-step CA-TIMS measurements of closed-system natural zircon samples. Chem. Geol. 275, 186–198 (2010).

  65. 65.

    Krogh, T. E. A low-contamination method for hydrothermal decomposition of zircon and extraction of U and Pb for isotopic age determinations. Geochim. Cosmochim. Acta 37, 485–494 (1973).

  66. 66.

    Corfu, F. U–Pb age, setting and tectonic significance of the anorthosite–mangerite–charnockite–granite suite, Lofoten–Vesterålen, Norway. J. Petrol. 45, 1799–1819 (2004).

  67. 67.

    Stacey, J. S. & Kramers, J. D. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet. Sci. Lett. 26, 207–221 (1975).

  68. 68.

    Schärer, U. The effect of initial 230Th disequilibrium on young U–Pb ages: the Makalu case, Himalaya. Earth Planet. Sci. Lett. 67, 191–204 (1984).

  69. 69.

    Jaffey, A. H., Flynn, K. F., Glendenin, L. E., Bentley, W. C. & Essling, A. M. Precision measurement of half-lives and specific activities of 235U and 238U. Phys. Rev. C 4, 1889–1906 (1971).

Download references


This research was financially supported by the Natural Sciences and Engineering Research Council of Canada (Discovery Grant RGPIN-2014-05681 to C.G. and RGPIN-2015-04080 to M.A.S.), the Canadian Foundation for Innovation (Projects 34991 to C.G. and 229814 to M.A.S.) and European Research Council (Starting Grant 306810 (SINK) and NWO Vidi grant 864.11.004 to D.J.J.v.H). We thank M. Al Battashi (Sultanate of the Oman Ministry of Commerce and Industry, Directorate General of Minerals) for permission to undertake field sampling in Oman.

Author information


  1. E4m, Département de Géologie et de Génie Géologique, Université Laval, Québec, Québec, Canada

    • Carl Guilmette
    •  & Olivier Rabeau
  2. PCIGR, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada

    • Matthijs A. Smit
  3. Department of Earth Sciences, Utrecht University, Utrecht, the Netherlands

    • Douwe J. J. van Hinsbergen
    •  & Derya Gürer
  4. Department of Geosciences and CEED, University of Oslo, Oslo, Norway

    • Fernando Corfu
  5. Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada

    • Benoit Charette
  6. School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom

    • Marco Maffione
  7. LabMaTer, Département de Génie Géologique, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada

    • Dany Savard


  1. Search for Carl Guilmette in:

  2. Search for Matthijs A. Smit in:

  3. Search for Douwe J. J. van Hinsbergen in:

  4. Search for Derya Gürer in:

  5. Search for Fernando Corfu in:

  6. Search for Benoit Charette in:

  7. Search for Marco Maffione in:

  8. Search for Olivier Rabeau in:

  9. Search for Dany Savard in:


C.G. generated the project, led the field work, completed the petrological study and wrote the manuscript. M.S. conducted the Lu–Hf analyses and contributed to writing the manuscript. D.J.J.v.H. participated in the field work, and contributed to the rationale and writing of the manuscript. D.G. and F.C. completed the U–Pb geochronological analyses. B.C. planned and participated in the field work, and prepared and analysed the samples. M.M. organized and participated in the field work. O.R. participated in defining the rationale and writing the manuscript. D.S. conducted the laser ablation ICP analyses.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Carl Guilmette.

Supplementary information

  1. Supplementary Table 1

    Electron microprobe spot analyses of garnet.

  2. Supplementary Table 2

    Laser ablation ICP-MS spot analyses of garnet.

  3. Supplementary Tables

    Supplementary Tables 3 and 4.

About this article

Publication history