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.

  • Letter
  • Published:

Perennial water ice identified in the south polar cap of Mars

Abstract

The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet1. From the early mapping observation of the permanent ice caps on the martian poles2,3, the northern cap was believed to be mainly composed of water ice, whereas the southern cap was thought to be constituted of carbon dioxide ice. However, recent missions (NASA missions Mars Global Surveyor and Odyssey) have revealed surface structures4, altimetry profiles5, underlying buried hydrogen6, and temperatures of the south polar regions that are thermodynamically consistent with a mixture of surface water ice and carbon dioxide7. Here we present the first direct identification and mapping of both carbon dioxide and water ice in the martian high southern latitudes, at a resolution of 2 km, during the local summer, when the extent of the polar ice is at its minimum. We observe that this south polar cap contains perennial water ice in extended areas: as a small admixture to carbon dioxide in the bright regions; associated with dust, without carbon dioxide, at the edges of this bright cap; and, unexpectedly, in large areas tens of kilometres away from the bright cap.

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

Access options

Buy this article

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

Figure 1: Global maps of CO2 and H2O ices at the south pole of Mars.
Figure 2: Near-infrared spectra of CO2 ice and H2O ice in Mars polar units.
Figure 3: Correlated variations of the CO2 ice, H2O ice and albedo.
Figure 4: Transition from CO2 ice to H2O ice.

Similar content being viewed by others

References

  1. Kieffer, H. H. & Zent, A. A. Mars (eds Kieffer, H. H., Jakovsky, B. M., Snyder, C. W. & Matthews, M. S.) 1180–1220 (Univ. Arizona Press, Tucson/London, 1992)

    Google Scholar 

  2. Kieffer, H. H. Mars south polar spring and summer temperatures: a residual CO2 frost. J. Geophys. Res. 84, 8263–8288 (1979)

    Article  ADS  Google Scholar 

  3. Paige, D. A., Herkenhoff, K. E. & Murray, B. C. Mariner 9 observations of the south polar cap of Mars: evidence of residual CO2 frost. J. Geophys. Res. 95, 1319–1335 (1990)

    Article  ADS  Google Scholar 

  4. Smith, P. H. et al. The global topography of Mars and implications for surface evolution. Science 284, 1495–1503 (1999)

    Article  ADS  CAS  Google Scholar 

  5. Schenk, P. M. & Moore, J. M. Stereo topography of the south polar region of Mars: Volatile inventory and Mars Polar Lander landing site. J. Geophys. Res. E 105, 24529–24546 (2000)

    Article  ADS  Google Scholar 

  6. Boynton, W. V. et al. Distribution of hydrogen in the near surface of Mars: Evidence for subsurface ice deposits. Science 297, 81–85 (2002)

    Article  ADS  CAS  Google Scholar 

  7. Titus, N., Kieffer, H. H. & Christensen, P. R. Exposed water ice discovered near the South Pole of Mars. Science 299, 1048–1051 (2003)

    Article  ADS  CAS  Google Scholar 

  8. Mars Express Project Team. Mars Express: closing in on the Red Planet. ESA Bull. 115, 10–17 (2003)

    ADS  Google Scholar 

  9. Bibring, J.-P. et al. OMEGA: Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité, (SP-1240, ESA, in the press)

  10. Herkenhoff, K. E. Geologic Map of the MTM-85000 Quadrangle, Planum Australe Region of Mars (USGS Geologic Investigations Map Series I-2686, Washington, DC, 2001)

    Google Scholar 

  11. Thomas, P. C. et al. North–south geological differences between the residual polar caps on Mars. Nature 404, 161–164 (2000)

    Article  ADS  CAS  Google Scholar 

  12. Byrne, S. & Ingersoll, A. P. A sublimation model for martian south polar ice features. Science 299, 1051–1053 (2003)

    Article  ADS  CAS  Google Scholar 

  13. Nye, J. F., Durham, W. B., Schenk, P. M. & Moore, J. M. The instability of a south polar cap on Mars composed of carbon dioxide. Icarus 144, 449–455 (2000)

    Article  ADS  CAS  Google Scholar 

  14. Clifford, S. M. et al. The state and future of Mars polar science and exploration. Icarus 144, 210–242 (2000)

    Article  ADS  CAS  Google Scholar 

  15. Poulet, F., Cuzzi, J. N., Cruikshank, D. P., Roush, T. & Dalle Ore, C. M. Comparison between the Shkuratov and Hapke scattering theories for solid planetary surfaces: Application to the surface composition of two Centaurs. Icarus 160, 313–324 (2002)

    Article  ADS  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jean-Pierre Bibring.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bibring, JP., Langevin, Y., Poulet, F. et al. Perennial water ice identified in the south polar cap of Mars. Nature 428, 627–630 (2004). https://doi.org/10.1038/nature02461

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature02461

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