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.

  • Article
  • Published:

Formation of mega-scale glacial lineations observed beneath a West Antarctic ice stream

Abstract

Most discharge from large ice sheets takes place through fast-flowing ice streams and their speed is strongly modulated by interactions between the ice and the underlying sediments. Seismic surveys and investigations through boreholes have revealed a spatial association between fast ice flow and saturated deformable sediments. Nevertheless, our knowledge of the morphology of the interface between ice and sediments is still limited, resulting in only rudimentary understanding of the basal boundary conditions beneath ice streams and the generation of subglacial bedforms. Here we present radar data from the bed of a West Antarctic ice stream that reveal the presence of mega-scale glacial lineations. We combine these data with previously published seismic data and show that these lineations develop in areas of dilatant deforming till and are part of a dynamic sedimentary system that undergoes significant change by erosion and deposition on decadal timescales. We find that the mega-scale glacial lineations are indistinguishable from those found on beds of palaeo-ice streams, providing conclusive evidence for the hypothesis that highly elongate bedforms are a characteristic of fast-flow regions in ice sheets.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Location map for radar survey.
Figure 2: Radar results.
Figure 3: Comparison between radar and seismic data.
Figure 4: Comparison of modern and relict bedforms.

Similar content being viewed by others

References

  1. Rose, K. E. Characteristics of ice flow in Marie Byrd Land, Antarctica. J. Glaciol. 24, 63–75 (1979).

    Article  Google Scholar 

  2. Alley, R. B., Blankenship, D. D., Bentley, C. R. & Rooney, S. T. Deformation of till beneath ice stream-B, West Antarctica. Nature 322, 57–59 (1986).

    Article  Google Scholar 

  3. Blankenship, D. D., Bentley, C. R., Rooney, S. T. & Alley, R. B. Seismic measurements reveal a saturated porous layer beneath an active Antarctic ice stream. Nature 322, 54–57 (1986).

    Article  Google Scholar 

  4. Engelhardt, H., Humphrey, N., Kamb, B. & Fahnestock, M. Physical conditions at the base of a fast moving Antarctic ice stream. Science 248, 57–59 (1990).

    Article  Google Scholar 

  5. Anandakrishnan, S., Blankenship, D. D., Alley, R. B. & Stoffa, P. L. Influence of subglacial geology on the position of a West Antarctic ice stream from seismic observations. Nature 394, 62–65 (1998).

    Article  Google Scholar 

  6. Engelhardt, H. & Kamb, B. Basal sliding of ice stream B, West Antarctica. J. Glaciol. 44, 223–230 (1998).

    Article  Google Scholar 

  7. Alley, R. B. In search of ice-stream sticky spots. J. Glaciol. 39, 447–454 (1993).

    Article  Google Scholar 

  8. Rooney, S. T., Blankenship, D. D., Alley, R. B. & Bentley, C. R. Till beneath ice stream-B.2. Structure and continuity. J. Geophys. Res. 92, 8913–8920 (1987).

    Article  Google Scholar 

  9. Smith, A. M. Basal conditions on Rutford ice stream, West Antarctica, from seismic observations. J. Geophys. Res. 102, 543–552 (1997).

    Article  Google Scholar 

  10. Smith, A. M. et al. Rapid erosion, drumlin formation, and changing hydrology beneath an Antarctic ice stream. Geology 35, 127–130 (2007).

    Article  Google Scholar 

  11. Smith, A. M. & Murray, T. Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream. Quat. Sci. Rev. 28, 584–596 (2008).

    Article  Google Scholar 

  12. Stokes, C. R. & Clark, C. D. Palaeo-ice streams. Quat. Sci. Rev. 20, 1437–1457 (2001).

    Article  Google Scholar 

  13. Clark, C. D. Mega-scale glacial lineations and cross-cutting ice-flow landforms. Earth Surf. Process. Landf. 18, 1–29 (1993).

    Article  Google Scholar 

  14. Ō Cofaigh, C., Pudsey, C. J., Dowdeswell, J. A. & Morris, P. Evolution of subglacial bedforms along a paleo-ice stream, Antarctic Peninsula continental shelf. Geophys. Res. Lett. 29, 1199 (2002).

    Article  Google Scholar 

  15. Stokes, C. R. & Clark, C. D. Are long subglacial bedforms indicative of fast ice flow? Boreas 31, 239–249 (2002).

    Article  Google Scholar 

  16. Clark, C. D., Tulaczyk, S. M., Stokes, C. R. & Canals, M. A groove-ploughing theory for the production of mega-scale glacial lineations, and implications for ice-stream mechanics. J. Glaciol. 49, 240–256 (2003).

    Article  Google Scholar 

  17. Shaw, J., Pugin, A. & Young, R. R. A meltwater origin for Antarctic shelf bedforms with special attention to megalineations. Geomorphology 102, 364–375 (2008).

    Article  Google Scholar 

  18. Wellner, J. S., Heroy, D. C. & Anderson, J. B. The death mask of the Antarctic ice sheet: Comparison of glacial geomorphic features across the continental shelf. Geomorphology 75, 157–171 (2006).

    Article  Google Scholar 

  19. Smith, A. M. Microearthquakes and subglacial conditions. Geophys. Res. Lett. 33, L24501 (2006).

    Article  Google Scholar 

  20. Boulton, G. S. & Hindmarsh, R. C. A. Sediment deformation beneath glaciers: Rheology and geological consequences. J. Geophys. Res. 92, 9059–9082 (1987).

    Article  Google Scholar 

  21. Murray, T., Corr, H., Forieri, A. & Smith, A. M. Contrasts in hydrology between regions of basal deformation and sliding beneath Rutford Ice Stream, West Antarctica, mapped using radar and seismic data. Geophys. Res. Lett. 35, L12504 (2008).

    Article  Google Scholar 

  22. Vaughan, D. G., Smith, A. M., Nath, P. C. & Le Meur, E. Acoustic impedance and basal shear stress beneath four Antarctic ice streams. Ann. Glaciol. 36, 225–232 (2003).

    Article  Google Scholar 

  23. Christoffersen, P. & Tulaczyk, S. Response of subglacial sediments to basal freeze-on - 1. Theory and comparison to observations from beneath the West Antarctic Ice Sheet. J. Geophys. Res. 108, 2222 (2003).

    Article  Google Scholar 

  24. Dowdeswell, J. A., Ottesen, D., Evans, J., Ō Cofaigh, C. & Anderson, J. B. Submarine glacial landforms and rates of ice-stream collapse. Geology 36, 819–822 (2008).

    Article  Google Scholar 

  25. Larter, R. D. et al. Subglacial bedforms reveal complex basal regime in a zone of paleo-ice stream convergence, Amundsen Sea embayment, West Antarctica. Geology 37, 411–414 (2009).

    Article  Google Scholar 

  26. Wingham, D. J., Siegert, M. J., Shepherd, A. & Muir, A. S. Rapid discharge connects Antarctic subglacial lakes. Nature 440, 1033–1036 (2006).

    Article  Google Scholar 

  27. King, E. C., Woodward, J. & Smith, A. M. Seismic and radar observations of subglacial bed forms beneath the onset zone of Rutford Ice Stream Antarctica. J. Glaciol. 53, 665–672 (2007).

    Article  Google Scholar 

  28. Schoof, C. G. & Clarke, G. K. C. A model for spiral flows in basal ice and the formation of subglacial flutes based on a Reiner-Rivlin rheology for glacial ice. J. Geophys. Res. 113, B05204 (2008).

    Article  Google Scholar 

  29. Dunlop, P., Clark, C. D. & Hindmarsh, R. C. A. Bed ribbing instability explanation: Testing a numerical model of ribbed moraine formation arising from coupled flow of ice and subglacial sediment. J. Geophys. Res. 113, F03005 (2008).

    Google Scholar 

  30. Hindmarsh, R. C. A. Drumlinization and drumlin-forming instabilities: Viscous till mechanisms. J. Glaciol. 44, 293–314 (1998).

    Article  Google Scholar 

  31. Hart, J. K. Identifying fast ice flow from landform assemblages in the geological record: A discussion. Ann. Glaciol. 28, 59–66 (1999).

    Article  Google Scholar 

Download references

Acknowledgements

We thank A. M. Smith for permission to use the seismic interpretations shown in Fig. 3. R. Stilwell and the Operations staff of Rothera Research Station are thanked for support in the field.

Author information

Authors and Affiliations

Authors

Contributions

E.C.K. collected and processed the radar data, prepared the figures and wrote the draft paper. C.R.S. and R.C.A.H. contributed to the interpretation of the data and the writing of the paper.

Corresponding author

Correspondence to E. C. King.

Rights and permissions

Reprints and permissions

About this article

Cite this article

King, E., Hindmarsh, R. & Stokes, C. Formation of mega-scale glacial lineations observed beneath a West Antarctic ice stream. Nature Geosci 2, 585–588 (2009). https://doi.org/10.1038/ngeo581

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo581

This article is cited by

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