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Complex layered deformation within the Aegean crust and mantle revealed by seismic anisotropy

Nature Geoscience volume 4, pages 203207 (2011) | Download Citation

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Abstract

Continental lithosphere can undergo pervasive internal deformation, often distributed over broad zones near plate boundaries. However, because of the paucity of observational constraints on three-dimensional movement at depth, patterns of flow within the lithosphere remain uncertain. Endmember models for lithospheric flow invoke deformation localized on faults or deep shear zones or, alternatively, diffuse, viscous-fluid-like flow. Here we determine seismic Rayleigh-wave anisotropy in the crust and mantle of the Aegean region, an archetypal example of continental deformation. Our data reveal a complex, depth-dependent flow pattern within the extending lithosphere. Beneath the northern Aegean Sea, fast shear wave propagation is in a North–South direction within the mantle lithosphere, parallel to the extensional component of the current strain rate field. In the south-central Aegean, where deformation is weak at present, anisotropic fabric in the lower crust runs parallel to the direction of palaeo-extension in the Miocene. The close match of orientations of regional-scale anisotropic fabric and the directions of extension during the last significant episodes of deformation implies that at least a large part of the extension in the Aegean has been taken up by distributed viscous flow in the lower crust and lithospheric mantle.

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Change history

  • 02 February 2011

    In the version of this Article originally published online, the label 'Lower crust' was missing from the top of Fig. 2b. This error has now been corrected in all versions of the text.

References

  1. 1.

    & Exhumation of high-pressure rocks driven by slab rollback. Earth Planet. Sci. Lett 272, 1–7 (2008).

  2. 2.

    , , & One-dimensional models of shear wave velocity for the eastern Mediterranean obtained from the inversion of Rayleigh wave phase velocities and tectonic implications. Geophys. J. Int. 156, 45–58 (2004).

  3. 3.

    , , , & Nappe stacking resulting from subduction of oceanic and continental lithosphere below Greece. Geology 33, 325–328 (2005).

  4. 4.

    & 45 m.y. of Aegean crust and mantle flow driven by trench retreat. Geology 38, 815–818 (2010).

  5. 5.

    Active tectonics of the Mediterranean region. Geophys. J. R. Astron. Soc. 30, 109–185 (1972).

  6. 6.

    & The Aegean Sea. Phil. Trans. R. Soc. Lond. A 300, 357–372 (1981).

  7. 7.

    & Mediterranean extension and the Africa–Eurasia collision. Tectonics 19, 1095–1106 (2000).

  8. 8.

    , & Metamorphic core complexes of Cordilleran type in the Cyclades, Aegean Sea, Greece. Geology 12, 221–225 (1984).

  9. 9.

    , , & in Collision and Collapse at the Africa–Arabia–Eurasia Subduction Zone311 (eds van Hinsbergen, D. J. J., Edwards, M. A. & Govers, R.) 257–292 (Spec. Publ. Geol. Soc. Lond., 2009).

  10. 10.

    & Constraints on the kinematics of post-orogenic extension imposed by stretching lineations in the Aegean region. Tectonophysics 298, 155–175 (1998).

  11. 11.

    , , , & Quaternary evolution of the Corinth Rift and its implications for the Late Cenozoic evolution of the Aegean. Geophys. J. Int. 126, 11–53 (1996).

  12. 12.

    , , & Aegean crustal thickness inferred from gravity inversion. Geodynamical implications. Earth Planet. Sci. Lett. 228, 267–280 (2004).

  13. 13.

    et al. Global Positioning System constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus. J. Geophys. Res. 105, 5695–5719 (2000).

  14. 14.

    , , , & Geodetic constraints on the tectonic evolution of the Aegean region and strain accumulation along the Hellenic subduction zone. Tectonophysics 488, 22–30 (2010).

  15. 15.

    et al. A new velocity field for Greece: Implications for the kinematics and dynamics of the Aegean. J. Geophys. Res. 115, B10403 (2010).

  16. 16.

    , & Constraints on the evolution and vertical coherency of deformation in the Northern Aegean from a comparison of geodetic, geologic and seismologic data. Earth Planet. Sci. Lett. 225, 329–346 (2004).

  17. 17.

    , & Active tectonics of the north and central Aegean Sea. Geophys. J. Int. 106, 433–490 (1991).

  18. 18.

    & Shallow structure and recent evolution of the Aegean Sea: A synthesis based on continuous reflection profiles. Mar. Geol. 94, 271–299 (1990).

  19. 19.

    & A detailed study of the active crustal deformation in the Aegean and surrounding area. Tectonophysics 253, 129–153 (1996).

  20. 20.

    , & From mantle to crust: Stretching the Mediterranean. Earth Planet. Sci. Lett. 285, 198–209 (2009).

  21. 21.

    & The Miocene-to-present kinematic evolution of the Eastern Mediterranean and Middle East and its implications for dynamics. Annu. Rev. Earth Planet. Sci. 38, 323–351 (2010).

  22. 22.

    , & The motion of crustal blocks driven by flow of the lower lithosphere and implications for slip rates of continental strike-slip faults. Nature 391, 655–659 (1998).

  23. 23.

    & Cenozoic tectonics of Asia: Effects of a continental collision. Science 189, 419–426 (1975).

  24. 24.

    Continental tectonics in the aftermath of plate tectonics. Nature 335, 131–137 (1988).

  25. 25.

    On the relation between seismic anisotropy and finite strain. J. Geophys. Res. 97, 8737–8747 (1992).

  26. 26.

    , , & Viscoplastic self-consistent and equilibrium-based modeling of olivine lattice preferred orientations: Implications for the upper mantle seismic anisotropy. J. Geophy. Res. 105, 7893–7908 (2000).

  27. 27.

    , , & Amphibole and lower crustal seismic properties. Earth Planet. Sci. Lett. 267, 118–128 (2008).

  28. 28.

    , , & Statistical properties of seismic anisotropy predicted by upper mantle geodynamic models. J. Geophys. Res. 111, B08309 (2006).

  29. 29.

    et al. Shear wave anisotropy in the upper mantle beneath the Aegean related to internal deformation. J. Geophys. Res. 106, 30737–30753 (2001).

  30. 30.

    , & Delay times and shear wave splitting in the Mediterranean region. Geophys. J. Int. 159, 275–290 (2004).

  31. 31.

    & A simple method for inverting the azimuthal anisotropy of surface waves. J. Geophys. Res. 91, 511–520 (1986).

  32. 32.

    & Global upper mantle tomography of seismic velocities and anisotropies. J. Geophys. Res. 96, 20337–20351 (1991).

  33. 33.

    , , & Thinning and flow of Tibetan crust constrained by seismic anisotropy. Science 305, 233–236 (2004).

  34. 34.

    , , & Lithospheric and sublithospheric anisotropy beneath the Baltic shield from surface-wave array analysis. Earth Planet. Sci. Lett. 244, 590–605 (2006).

  35. 35.

    & Rayleigh wave phase velocities, small-scale convection, and azimuthal anisotropy beneath southern California. J. Geophys. Res. 111, B07306 (2006).

  36. 36.

    & The depth distribution of azimuthal anisotropy in the continental upper mantle. Nature 447, 198–201 (2007).

  37. 37.

    , , & Seismic evidence for widespread western-US deep-crustal deformation caused by extension. Nature 464, 885–889 (2010).

  38. 38.

    , , & Surface wave tomography of the Gulf of California. Geophys. Res. Lett. 34, L15305 (2007).

  39. 39.

    , , & Stratified seismic anisotropy reveals past and present deformation beneath the East-central United States. Earth Planet. Sci. Lett. 274, 489–498 (2008).

  40. 40.

    , , , , & S velocity structure and radial anisotropy in the Aegean region from surface wave dispersion. Geophys. J. Int. 174, 593–616 (2008).

  41. 41.

    , & An integrated global model of present-day plate motions and plate boundary deformation. Geophys. J. Int. 154, 8–34 (2003).

  42. 42.

    et al. Continuous deformation versus faulting through the continental lithosphere of New Zealand. Science 286, 516–519 (1999).

  43. 43.

    & Core complex geometries and regional scale flow in the lower crust. Tectonics 9, 557–567 (1990).

  44. 44.

    & Development of shape and lattice preferred orientations: Application to the seismic anisotropy of the lower crust. J. Struct. Geol. 11, 175–189 (1989).

  45. 45.

    , , & The geometry of the Wadati–Benioff zone and the lithospheric kinematics in the Hellenic arc. Tectonophysics 319, 275–300 (2000).

  46. 46.

    et al. in The Geodynamics of the Aegean and Anatolia291 (eds Taymaz, T., Yilmaz, Y. & Dilek, Y.) 183–199 (Spec. Publ. Geol.Soc. Lond., 2007).

  47. 47.

    , , , & Modeling the influence of Moho topography on receiver functions: A case study from the central Hellenic subduction zone. Geophys. Res. Lett. 32, L12311 (2005).

  48. 48.

    & Subduction and slab detachment in the Mediterranean–Carpathian region. Science 290, 1910–1917 (2000).

  49. 49.

    & P wave tomography of the mantle under the Alpine–Mediterranean area. J. Geophys. Res. 108, 2065 (2003).

  50. 50.

    & Global upper-mantle tomography with the automated multimode inversion of surface and S-wave forms. Geophys. J. Int. 173, 505–518 (2008).

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Acknowledgements

This work was funded by the German Research Foundation within Collaborative Research Centre SFB 526 ‘Rheology of the Earth’ and by Science Foundation Ireland (grant 08/RFP/GE01704). Earthquake data were provided by NOA, Greece (thanks to G. Stavrakakis), and GEOFON, GFZ Potsdam. We thank GIPP, GFZ Potsdam, for supplying seismic acquisition systems for CYCNET. The authors acknowledge D. Hatzfeld for contributing a digital version of his SKS data set, E. Sandvol for providing the results of the Pn tomography by Al-Latzki et al. (Supplementary Information), and T. Becker for stimulating discussions.

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Affiliations

  1. Institute of Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht-Straße 24, 14476 Potsdam, Germany

    • Brigitte Endrun
  2. Dublin Institute for Advanced Studies, Geophysics Section, 5 Merrion Square, Dublin 2, Ireland

    • Sergei Lebedev
    •  & Céline Tirel
  3. Institute of Geosciences, Christian-Albrechts University of Kiel, Otto-Hahn-Platz 1, 24118 Kiel, Germany

    • Thomas Meier
  4. Institute of Geology, Mineralogy and Geophysics, Ruhr-University Bochum, 44780 Bochum, Germany

    • Wolfgang Friederich

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Contributions

B.E. performed measurements, computed and analysed seismic models, and wrote the first draft. S.L. and T.M. contributed software and revised the manuscript extensively. T.M. initiated the study. T.M. and W.F. secured primary funding for this work. C.T. contributed tectonics and geodynamics expertise and implemented Fig. 4; all authors contributed ideas and discussed the results and implications.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Brigitte Endrun.

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DOI

https://doi.org/10.1038/ngeo1065

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