Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Lower-crustal intrusion on the North Atlantic continental margin

Abstract

When continents break apart, the rifting is sometimes accompanied by the production of large volumes of molten rock1,2,3. The total melt volume, however, is uncertain, because only part of it has erupted at the surface. Furthermore, the cause of the magmatism is still disputed—specifically, whether or not it is due to increased mantle temperatures. We recorded deep-penetration normal-incidence and wide-angle seismic profiles across the Faroe and Hatton Bank volcanic margins in the northeast Atlantic. Here we show that near the Faroe Islands, for every 1 km along strike, 360–400 km3 of basalt is extruded, while 540–600 km3 is intruded into the continent–ocean transition. We find that lower-crustal intrusions are focused mainly into a narrow zone 50 km wide on the transition, although extruded basalts flow more than 100 km from the rift. Seismic profiles show that the melt is intruded into the lower crust as sills, which cross-cut the continental fabric, rather than as an ‘underplate’ of 100 per cent melt, as has often been assumed. Evidence from the measured seismic velocities and from igneous thicknesses are consistent with the dominant control on melt production being increased mantle temperatures, with no requirement for either significant active small-scale mantle convection under the rift or the presence of fertile mantle at the time of continental break-up, as has previously been suggested for the North Atlantic Ocean4,5,6.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Location of seismic profiles across the North Atlantic rifted continental margins4,5,13,14.
Figure 2: Seismic velocity profiles.
Figure 3: Crustal velocities and thicknesses.

References

  1. White, R. & McKenzie, D. Magmatism at rift zones: The generation of volcanic continental margins and flood basalts. J. Geophys. Res. 94, 7685–7729 (1989)

    ADS  Article  Google Scholar 

  2. Coffin, M. F. & Eldholm, O. Large igneous provinces: crustal structure, dimensions, and external consequences. Rev. Geophys. 32, 1–36 (1994)

    ADS  Article  Google Scholar 

  3. Eldholm, O. & Grue, K. North Atlantic volcanic margins: dimensions and production rates. J. Geophys. Res. 99, 2955–2988 (1994)

    ADS  Article  Google Scholar 

  4. Korenaga, J. et al. Crustal structure of the southeast Greenland margin from joint refraction and reflection seismic tomography. J. Geophys. Res. 105, 21591–21614 (2000)

    ADS  Article  Google Scholar 

  5. Hopper, J. R. et al. Structure of the SE Greenland margin from seismic reflection and refraction data: Implications for nascent spreading center subsidence and asymmetric crustal accretion during North Atlantic opening. J. Geophys. Res. 108 (B5). 2269–2291 (2003)

    ADS  Article  Google Scholar 

  6. Korenaga, J., Kelemen, P. B. & Holbrook, W. S. Methods for resolving the origin of large igneous provinces from crustal seismology. J. Geophys. Res. 107 (B9). 10.1029/2001JB001030 (2002)

  7. White, R. S. et al. Magmatism at rifted continental margins. Nature 330, 439–444 (1987)

    ADS  Article  Google Scholar 

  8. Barton, A. J. & White, R. S. Crustal structure of the Edoras Bank continental margin and mantle thermal anomalies beneath the North Atlantic. J. Geophys. Res. 102, 3109–3129 (1997)

    ADS  Article  Google Scholar 

  9. Larsen, H. C. & Saunders, A. D. in Proceedings of the Ocean Drilling Program, Scientific Results (eds A. D. Saunders, H. C. Larsen & S. W. Wise, Jr) Vol. 152 503–533 (Ocean Drilling Program, College Station, Texas, 1998)

    Google Scholar 

  10. Weigel, W. et al. Investigations of the east Greenland continental margin between 70° and 72° N by deep seismic sounding and gravity studies. Mar. Geophys. Res. 17, 167–199 (1995)

    Article  Google Scholar 

  11. Klingelhöfer, F., Edwards, R. A., Hobbs, R. W. & England, R. W. Crustal structure of the NE Rockall Trough from wide-angle seismic data modelling. J. Geophys. Res. 110 B11105 10.1029/2005JB003763 (2005)

    ADS  Article  Google Scholar 

  12. White, R. S. et al. iSIMM pushes frontiers of marine seismic acquisition. First Break 20, 782–786 (2002)

    Google Scholar 

  13. Roberts, A. W., White, R. S., Lunnon, Z. C., Christie, P. A. F. & Spitzer, R. iSIMM Team. In Petroleum Geology: North-West Europe and Global Perspectives—Proc. 6th Petroleum Geology Conf. (eds A. G. Doré & B. A. Vining) 755–766 (Geol. Soc. London, 2005)

    Google Scholar 

  14. Smith, L. K., White, R. S. & Kusznir, N. J. iSIMM Team. In Petroleum Geology: North-West Europe and Global Perspectives—Proc. 6th Petroleum Geology Conf. (eds A. G. Doré & B. A. Vining) 947–956 (Geol. Soc. London, 2005)

    Google Scholar 

  15. Christeson, G. L., McIntosh, K. D. & Karson, J. A. Inconsistent correlation of seismic layer 2a and lava layer thickness in oceanic crust. Nature 445, 418–421 (2007)

    CAS  ADS  Article  Google Scholar 

  16. White, R. S. et al. Imaging and regional distribution of basalt flows in the Faroe-Shetland Basin. Geophysical Prospecting 51, 215–231 (2003)

    ADS  Article  Google Scholar 

  17. Mutter, J. C., Talwani, M. & Stoffa, P. L. Origin of seaward-dipping reflectors in oceanic crust off the Norwegian margin by subaerial sea-floor spreading. Geology 10, 353–357 (1982)

    ADS  Article  Google Scholar 

  18. Smallwood, J. R., White, R. S. & Staples, R. K. Deep crustal reflectors under Reydarfjördur, eastern Iceland: Crustal accretion above the Iceland mantle plume. Geophys. J. Int. 134, 277–290 (1998)

    ADS  Article  Google Scholar 

  19. Smallwood, J. R., Staples, R. K., Richardson, K. R. & White, R. S. FIRE Working Group. Crust generated above the Iceland mantle plume: from continental rift to oceanic spreading center. J. Geophys. Res. 104, 22885–22902 (1999)

    ADS  Article  Google Scholar 

  20. McBride, J. H., White, R. S., Smallwood, J. R. & England, R. W. Must magmatic intrusion in the lower crust produce reflectivity? Tectonophysics 388, 271–297 (2004)

    ADS  Article  Google Scholar 

  21. Parkin, C. J., Lunnon, Z. C., White, R. S. & Christie, P. A. F. iSIMM Team. Imaging the pulsing Iceland mantle plume through the Eocene. Geology 35, 93–96 (2007)

    ADS  Article  Google Scholar 

  22. Cox, K. G. A model for flood basalt vulcanism. J. Petrol. 21, 629–650 (1980)

    ADS  Article  Google Scholar 

  23. Sallarès, V., Charvis, P., Flueh, E. R. & Bialas, J. the SALIERI Scientific Party. Seismic structure of the Carnegie ridge and the nature of the Galápagos hotspot. Geophys. J. Int. 161, 763–788 (2005)

    ADS  Article  Google Scholar 

  24. White, R. S., McKenzie, D. & O'Nions, R. K. Oceanic crustal thickness from seismic measurements and rare earth element inversions. J. Geophys. Res. 97, 19683–19715 (1992)

    ADS  Article  Google Scholar 

  25. Bown, J. W. & White, R. S. Variation with spreading rate of oceanic crustal thickness and geochemistry. Earth Planet. Sci. Lett. 121, 435–449 (1994)

    CAS  ADS  Article  Google Scholar 

  26. Nielsen, T. K. & Hopper, J. R. Formation of volcanic rifted margins: Are temperature anomalies required? Geophys. Res. Lett. 29 2022 10.129/2002GL015681 (2002)

    ADS  Article  Google Scholar 

  27. Lunnon, Z. C., Christie, P. A. F. & White, R. S. An evaluation of peak and bubble tuning in sub-basalt seismology: modelling and results. First Break 21, 51–56 (2003)

    Google Scholar 

  28. Maresh, J. & White, R. S. Seeing through a glass, darkly: strategies for imaging through basalt. First Break 23, 27–32 (2005)

    Article  Google Scholar 

  29. Zelt, C. A. & Barton, P. J. Three-dimensional seismic refraction tomography: a comparison of two methods applied to data from the Faeroe Basin. J. Geophys. Res. 103 (B4). 7187–7210 (1998)

    ADS  Article  Google Scholar 

  30. Zelt, C. A. & Smith, R. B. Seismic traveltime inversion for 2-D crustal velocity structure. Geophys. J. Int. 108, 16–34 (1992)

    ADS  Article  Google Scholar 

  31. Parkin, C. J. Crustal Formation and the Influence of a Mantle Plume Following Continental Breakup of the Northern North Atlantic. 1–225, PhD dissertation, Univ. Cambridge. (2006)

    Google Scholar 

  32. Roberts, A. W. Crustal Structure of the Faroes North Atlantic Margin from Wide-Angle Seismic Data. 1–230, PhD dissertation, Univ. Cambridge. (2007)

    Google Scholar 

  33. Smith, L. K. Crustal Structure of Hatton Bank Volcanic Continental Margin from Traveltime Inversion of Wide-Angle Data. 1–227, PhD dissertation, Univ. Cambridge. (2006)

    Google Scholar 

Download references

Acknowledgements

iSIMM was supported by Liverpool and Cambridge Universities, Schlumberger Cambridge Research Ltd, Badley Geoscience Ltd, WesternGeco, Amerada Hess, Anadarko, BP, ConocoPhillips, ENI UK, Statoil, Shell, the Natural Environment Research Council and the Department of Trade and Industry. OBSs were provided by Geopro GmbH and Q-Marine streamer acquisition by WesternGeco.

Author Contributions Wide-angle seismic analysis was undertaken by L.K.S. and A.W.R. as part of their PhD research. Seismic reflection processing for Fig. 2c was by WesternGeco. R.S.W. led the work at sea on RRS Discovery on the Faroes profile, N.J.K. on the Hatton profile, and P.A.F.C. oversaw the Faroes seismic profiling on MV Geco Topaz. R.S.W. wrote the paper and all authors discussed the results and commented on the manuscript.

Author information

Authors and Affiliations

Authors

Consortia

Corresponding author

Correspondence to R. S. White.

Supplementary information

Supplementary Figures

The file contains Supplementary Figures S1-S8 with Legends. (PDF 11028 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

White, R., Smith, L., Roberts, A. et al. Lower-crustal intrusion on the North Atlantic continental margin. Nature 452, 460–464 (2008). https://doi.org/10.1038/nature06687

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature06687

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.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing