Skip to main content

Thank you for visiting 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.

Formation of recent martian gullies through melting of extensive water-rich snow deposits


The observation of gullies on Mars indicates the presence of liquid water near the surface in recent times1,2, which is difficult to reconcile with the current cold climate. Gullies have been proposed to form through surface runoff from subsurface aquifers1,3 or through melting of near-surface ice under warmer conditions4. But these gullies are observed to occur preferentially in cold mid-latitudes2, where the presence of liquid water is less likely, and on isolated surfaces where groundwater seepage would not be expected, making both potential explanations unsatisfactory. Here I show that gullies can form by the melting of water-rich snow that has been transported from the poles to mid-latitudes during periods of high obliquity within the past 105 to 106 years (refs 5, 6). Melting within this snow7 can generate sufficient water to erode gullies in about 5,000 years. My proposed model for gully formation is consistent with the age and location of the gullies, and it explains the occurrence of liquid water in the cold mid-latitudes as well as on isolated surfaces. Remnants of the snowpacks are still present on mid-latitude, pole-facing slopes, and the recent or current occurrence of liquid water within them provides a potential abode for life.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Examples of mid-latitude, pole-facing mantling materials and their curvilinear upper boundaries (arrows).
Figure 2: Detail of the appearance and curvilinear upper boundary (arrows) of pole-facing mantling materials located in Dao Valles.
Figure 3: THEMIS image showing gullies emerging from beneath and within a mantling snow unit where this unit is being removed.
Figure 4: MOC image of gullies with a remnant of the snow mantle (arrow) proposed to be the source of water that eroded these gullies.


  1. Malin, M. C. & Edgett, K. S. Evidence for recent ground water seepage and surface runoff on Mars. Science 288, 2330–2335 (2000)

    ADS  CAS  Article  Google Scholar 

  2. Malin, M. C. & Edgett, K. S. Mars Global Surveyor Mars Orbiter Camera: Interplanetary cruise through primary mission. J. Geophys. Res. 106, 23429–23570 (2001)

    ADS  Article  Google Scholar 

  3. Mellon, M. T. & Phillips, R. J. Recent gullies on Mars and the source of liquid water. J. Geophys. Res. 106, 23165–23180 (2001)

    ADS  CAS  Article  Google Scholar 

  4. Costard, F., Forget, F., Mangold, N. & Peulvast, J. P. Formation of recent martian debris flows by melting of near-surface ground ice at high obliquity. Science 295, 110–113 (2002)

    ADS  CAS  Article  Google Scholar 

  5. Jakosky, B. M. & Carr, M. A. Possible precipitation of ice at low latitudes of Mars during periods of high obliquity. Nature 315, 559–561 (1985)

    ADS  CAS  Article  Google Scholar 

  6. Jakosky, B. M., Henderson, B. G. & Mellon, M. T. Chaotic obliquity and the nature of the Martian climate. J. Geophys. Res. 100, 1579–1584 (1995)

    ADS  CAS  Article  Google Scholar 

  7. Clow, G. D. Generation of liquid water on Mars through the melting of a dusty snowpack. Icarus 72, 95–127 (1987)

    ADS  CAS  Article  Google Scholar 

  8. Knauth, L. P., Klonowski, S. & Burt, D. Ideas about the surface runoff features on Mars. Science 290, 711–712 (2000)

    CAS  Google Scholar 

  9. Knauth, L. P., Burt, D. M. & Tyburczy, J. A. in Conference on the Geophysical Detection of Subsurface Water on Mars 60–61 (Lunar and Planetary Institute Contribution No. 1095, Houston, Texas, 2001)

    Google Scholar 

  10. Musselwhite, D. S., Swindle, T. D. & Lunine, J. I. Liquid CO2 breakout and the formation of recent small channels on Mars. Geophys. Res. Lett. 28, 1283–1285 (2001)

    ADS  CAS  Article  Google Scholar 

  11. Toon, O. B., Pollack, J. B., Ward, W., Burns, J. A. & Bilski, K. The astronomical theory of climate change on Mars. Icarus 44, 552–607 (1980)

    ADS  Article  Google Scholar 

  12. Haberle, R. M. et al. On the possibility of liquid water on present-day Mars. J. Geophys. Res. 106, 23317–23326 (2001)

    ADS  CAS  Article  Google Scholar 

  13. Mustard, J. F., Cooper, C. D. & Rifkin, M. K. Evidence for recent climate change on Mars from the identification of youthful near-surface ground ice. Nature 412, 411–414 (2001)

    ADS  CAS  Article  Google Scholar 

  14. Carr, M. H. Mars Global Surveyor observations of fretted terrain. J. Geophys. Res. 106, 23571–23595 (2001)

    ADS  Article  Google Scholar 

  15. Gulick, V. C., Tyler, D., McKay, C. P. & Haberle, R. M. Episodic ocean-induced CO2 greenhouse on Mars: Implications for fluvial valley formation. Icarus 130, 68–86 (1997)

    ADS  CAS  Article  Google Scholar 

  16. Lee, P., Cockell, C. S., Marinova, M. M., McKay, C. P. & Rice, J. W. Snow and ice melt flow features in Devon Island, Nunavut, Arctic Canada as possible analogs for recent slope flow features on Mars. (abstract) Lunar Planet. Sci. [CD-ROM] 1809 (2001)

  17. Hecht, M. H. Metastability of liquid water on mars. Icarus 156, 373–386 (2002)

    ADS  CAS  Article  Google Scholar 

  18. Ward, W. R. Present obliquity oscillations of Mars: Fourth-order accuracy in orbital E and I. J. Geophys. Res. 84, 237–241 (1979)

    ADS  Article  Google Scholar 

  19. Kieffer, H. H., Chase, S. C. Jr, Martin, T. Z., Miner, E. D. & Palluconi, F. D. Martian North Pole summer temperatures: Dirty water ice. Science 194, 1341–1344 (1976)

    ADS  CAS  Article  Google Scholar 

  20. Howard, A. D. & C.F. McLane, I. Erosion of cohesionless sediment by groundwater seepage. Wat. Resour. Res. 24, 1659–1674 (1988)

    ADS  Article  Google Scholar 

  21. Feldman, W. C. et al. Global distribution of neutrons from Mars: Results from Mars Odyssey. Science 297, 75–78 (2002)

    ADS  CAS  Article  Google Scholar 

  22. Mitrofanov, I. et al. Maps of subsurface hydrogen from the high energy neutron detector, Mars Odyssey. Science 297, 78–81 (2002)

    ADS  CAS  Article  Google Scholar 

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

    ADS  CAS  Article  Google Scholar 

  24. Mellon, M. T. & Jakosky, B. M. The distribution and behavior of martian ground ice during past and present epochs. J. Geophys. Res. 100, 11781–11799 (1995)

    ADS  Article  Google Scholar 

  25. Tokar, R. L. et al. Ice concentration and distribution near the South Pole of Mars: Synthesis of Odyssey and Global Surveyor analyses. J. Geophys. Res. 29, doi:1029/2002GL015691 (2002)

  26. Malin, M. C. et al. Image M17-00423, Malin Space Science Systems Mars Orbiter Camera Image Gallery at 〈〉 (2002).

Download references


I thank the THEMIS instrument development team at Arizona State University and Raytheon Santa Barbara Remote Sensing, and the spacecraft development and operations teams at the Jet Propulsion Laboratory and Lockheed Martin Astronautics, for the development and performance of the THEMIS instrument and the Odyssey spacecraft. I also thank J. Rice, S. Ruff, H. Kieffer, M. Malin and B. Jakosky for discussions and contributions, and M. Carr and J. Mustard for comments that improved the original manuscript. This work was supported through the NASA Mars Odyssey Project and the NASA Mars Data Analysis Program.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Philip R. Christensen.

Ethics declarations

Competing interests

The author declares that he has no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Christensen, P. Formation of recent martian gullies through melting of extensive water-rich snow deposits. Nature 422, 45–48 (2003).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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.


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