Letter | Published:

The role of ridges in the formation and longevity of flat slabs

Nature volume 524, pages 212215 (13 August 2015) | Download Citation

Abstract

Flat-slab subduction occurs when the descending plate becomes horizontal at some depth before resuming its descent into the mantle. It is often proposed as a mechanism for the uplifting of deep crustal rocks (‘thick-skinned’ deformation) far from plate boundaries, and for causing unusual patterns of volcanism, as far back as the Proterozoic eon1. For example, the formation of the expansive Rocky Mountains and the subsequent voluminous volcanism across much of the western USA has been attributed to a broad region of flat-slab subduction beneath North America that occurred during the Laramide orogeny (80–55 million years ago)2. Here we study the largest modern flat slab, located in Peru, to better understand the processes controlling the formation and extent of flat slabs. We present new data that indicate that the subducting Nazca Ridge is necessary for the development and continued support of the horizontal plate at a depth of about 90 kilometres. By combining constraints from Rayleigh wave phase velocities with improved earthquake locations, we find that the flat slab is shallowest along the ridge, while to the northwest of the ridge, the slab is sagging, tearing, and re-initiating normal subduction. On the basis of our observations, we propose a conceptual model for the temporal evolution of the Peruvian flat slab in which the flat slab forms because of the combined effects of trench retreat along the Peruvian plate boundary, suction, and ridge subduction. We find that while the ridge is necessary but not sufficient for the formation of the flat slab, its removal is sufficient for the flat slab to fail. This provides new constraints on our understanding of the processes controlling the beginning and end of the Laramide orogeny and other putative episodes of flat-slab subduction.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    & Fossil flat-slab subduction beneath the Illinois basin, USA. Tectonophysics 424, 53–68 (2006)

  2. 2.

    et al. How Laramide-age hydration of North American lithosphere by the Farallon slab controlled subsequent activity in the western United States. Int. Geol. Rev. 45, 575–595 (2003)

  3. 3.

    Subduction and aseismic ridges. Nature 241, 189–191 (1973)

  4. 4.

    , & On the role of subducting oceanic plateaus in the development of shallow flat subduction. Tectonophysics 352, 317–333 (2002)

  5. 5.

    , & Chilean flat slab subduction controlled by overriding plate thickness and trench rollback. Geology 40, 35–38 (2012)

  6. 6.

    , , & Dynamic effects of aseismic ridge subduction: numerical modelling. Eur. J. Mineral. 21, 649–661 (2009)

  7. 7.

    & The lack of correlation between flat slabs and bathymetric impactors in South America. Earth Planet. Sci. Lett. 371–372, 1–5 (2013)

  8. 8.

    et al. Subduction of the Nazca Ridge and the Inca Plateau: insights into the formation of ore deposits in Peru. Earth Planet. Sci. Lett. 239, 18–32 (2005)

  9. 9.

    et al. Response of the mantle to flat slab evolution: insights from local S splitting beneath Peru. J. Geophys. Res. 41, 3438–3446 (2014)

  10. 10.

    et al. Ambient noise tomography across the Central Andes. Geophys. J. Int. 194, 1559–1573 (2013)

  11. 11.

    & Structure of the subduction transition region from seismic array data in southern Peru. Geophys. J. Int. 196, 1889–1905 (2014)

  12. 12.

    , & Seismicity and shape of the subducted Nazca plate. J. Geophys. Res. 97, 17503–17529 (1992)

  13. 13.

    , , & Slab 1.0: a three‐dimensional model of global subduction zone geometries. J. Geophys. Res. 117, B01302 (2012)

  14. 14.

    , & Subduction of the Nazca plate beneath Peru as determined from seismic observations. J. Geophys. Res. 6, 4971–4980 (1981)

  15. 15.

    , , & Report of heat flow measurements in Peru and Ecuador. Bull. Earthquake Res. Inst. 55, 55–74 (1980)

  16. 16.

    & Influence of geometry and eclogitization on oceanic plateau subduction. Earth Planet. Sci. Lett. 363, 34–43 (2013)

  17. 17.

    International Seismological Centre. On-line Bulletin (ISC, (2012)

  18. 18.

    et al. The role of oceanic plateau subduction in the Laramide orogeny. Nature Geosci. 3, 353–357 (2010)

  19. 19.

    , , & Hydrodynamic mechanism for the Laramide orogeny. Geosphere 7, 183–201 (2011)

  20. 20.

    , & Two-stage subduction history under North America inferred from multiple-frequency tomography. Nature Geosci. 1, 458–462 (2008)

  21. 21.

    & Young tracks of hotspots and current plate velocities. Geophys. J. Int. 150, 321–361 (2002)

  22. 22.

    Instituto Geológico Minero y Metalúrgico. On-line catalog. (INGEMMET, (2014)

  23. 23.

    , & HYPOCENTER: an earthquake location method using centered, scaled, and adaptively damped least squares. Bull. Seismol. Soc. Am. 76, 771–783 (1986)

  24. 24.

    & A double-difference earthquake location algorithm: method and application to the Northern Hayward Fault, California. Bull. Seismol. Soc. Am. 90, 1353–1368 (2000)

  25. 25.

    Velocity structure of the Andes of central Peru from locally recorded earthquakes. J. Geophys. Res. 23, 205–208 (1996)

  26. 26.

    & in Seismic Earth: Array of Broadband Seismograms (eds & ) 81–98 (Geophysical Monograph Series 157, 2005)

  27. 27.

    & Regional tomographic inversion of the amplitude and phase of Rayleigh waves with 2-D sensitivity kernels. Geophys. J. Int. 166, 1148–1160 (2006)

  28. 28.

    , & Three-dimensional sensitivity kernels for surface wave observables. Geophys. J. Int. 158, 142–168 (2004)

  29. 29.

    , , & Three-dimensional density model of the Nazca plate and the Andean continental margin. J. Geophys. Res. 111, B09404 (2006)

  30. 30.

    IASPEI 1991 Seismological Tables (Bibliotech, 1991)

  31. 31.

    Andean crustal and upper mantle structure. J. Geophys. Res. 76, 3246–3271 (1971)

  32. 32.

    in Seismological Algorithms: Computational Methods and Computer Programs. (ed. ) 293–319 (Elsevier, 1988)

  33. 33.

    , , , & Evidence for an upper mantle plume beneath the Tanzanian craton from Rayleigh wave tomography. J. Geophys. Res. 108, 2427 (2003)

  34. 34.

    et al. Imaging the transition from flat to normal subduction: variations in the structure of the Nazca slab and upper mantle under southern Peru and northwestern Bolivia. Geophys. J. Int. (submitted)

  35. 35.

    , & Determination of the subducting lithosphere boundary by use of converted phases. Bull. Seismol. Soc. Am. 67, 1051–1060 (1977)

Download references

Acknowledgements

We thank R. Clayton and P. Davies for providing the records from eight PERUSE stations. The PULSE experiment was supported by NSF grants EAR-0944184 (to L.S.W.), EAR-0943991 (to S.L.B.) and EAR-0943962 (to M.D.L.). The CAUGHT project was supported by NSF grants EAR-0908777 (to L.S.W.) and EAR-0907880 (to S.L.B.).

Author information

Affiliations

  1. Department of Geological Sciences, University of North Carolina at Chapel Hill, CB 3315, Chapel Hill, North Carolina 27599, USA

    • Sanja Knezevic Antonijevic
    •  & Abhash Kumar
  2. Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington DC 20015, USA

    • Lara S. Wagner
  3. Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721, USA

    • Susan L. Beck
    •  & George Zandt
  4. Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, Connecticut 06511, USA

    • Maureen D. Long
  5. Instituto Geofísico del Perú, Calle Badajoz 169, Lima 15012, Peru

    • Hernando Tavera
    •  & Cristobal Condori

Authors

  1. Search for Sanja Knezevic Antonijevic in:

  2. Search for Lara S. Wagner in:

  3. Search for Abhash Kumar in:

  4. Search for Susan L. Beck in:

  5. Search for Maureen D. Long in:

  6. Search for George Zandt in:

  7. Search for Hernando Tavera in:

  8. Search for Cristobal Condori in:

Contributions

S.K.A. generated the tomographic model. L.S.W. developed the model of temporal evolution. A.K. provided earthquake locations. S.K.A, L.S.W. and A.K. developed the ideas and wrote the paper. S.L.B., M.D.L., G.Z., H.T. and C.C. contributed to data collection and paper editing.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Sanja Knezevic Antonijevic.

Extended data

Supplementary information

Excel files

  1. 1.

    Supplementary Tables

    This file contains Supplementary Table 1.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature14648

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.