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:

Recurring slope lineae in equatorial regions of Mars

Nature Geoscience volume 7, pages 53–58 (2014)Cite this article

Subjects

Abstract

The presence of liquid water is a requirement of habitability on a planet. Possible indicators of liquid surface water on Mars include intermittent flow-like features observed on sloping terrains. These recurring slope lineae are narrow, dark markings on steep slopes that appear and incrementally lengthen during warm seasons on low-albedo surfaces. The lineae fade in cooler seasons and recur over multiple Mars years. Recurring slope lineae were initially reported to appear and lengthen at mid-latitudes in the late southern spring and summer and are more common on equator-facing slopes where and when the peak surface temperatures are higher. Here we report extensive activity of recurring slope lineae in equatorial regions of Mars, particularly in the deep canyons of Valles Marineris, from analysis of data acquired by the Mars Reconnaissance Orbiter. We observe the lineae to be most active in seasons when the slopes often face the sun. Expected peak temperatures suggest that activity may not depend solely on temperature. Although the origin of the recurring slope lineae remains an open question, our observations are consistent with intermittent flow of briny water. Such an origin suggests surprisingly abundant liquid water in some near-surface equatorial regions of Mars.

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

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

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

Figure 1: Locations of confirmed recurring slope lineae (RSL).
Figure 2: Portion of Coprates Chasma showing RSL on generally north-facing slopes in northern summer and southern winter.
Figure 3: RSL on the south-facing slope of a crater on the floor of Melas Chasma.
Figure 4: Thermal model for the crater on the floor of Melas Chasma (11.5° S, 290.3° E).

Similar content being viewed by others

References

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

    Article  Google Scholar 

  2. Brass, G. W. Stability of brines on Mars. Icarus 42, 20–28 (1980).

    Article  Google Scholar 

  3. McEwen, A. S. et al. Seasonal flows on warm Martian slopes. Science 333, 740–744 (2011).

    Article  Google Scholar 

  4. Mohlmann, D. Three types of liquid water in icy surfaces of celestial bodies. Planet. Space Sci. 59, 1082–1086 (2011).

    Article  Google Scholar 

  5. Cull, S. C. et al. Concentrated perchlorate at the Mars Phoenix landing site: Evidence for thin film liquid water on Mars. Geophys. Res. Lett. 37, L22203 (2010).

    Google Scholar 

  6. Chevrier, V. F. & Rivera-Valentin, E. G. Formation of recurring slope lineae by liquid brines on present-day Mars. Geophys. Res. Lett. 39, L21202 (2012).

    Article  Google Scholar 

  7. McClennan, S. M. in Sedimentary Geology of Mars (eds Grotzinger, J. & Milliken, R.) 119–138 (SEPM Special Publication No. 102, SEPM, 2012).

    Google Scholar 

  8. McEwen, A. S. et al. Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE). J. Geophys. Res. 112, E05S02 (2007).

    Article  Google Scholar 

  9. Ojha, L. et al. Recurring slope lineae on Mars: Updated global survey results. Lunar Planet. Sci. Conf. 43, 2591 (2012).

    Google Scholar 

  10. Smith, D. E. et al. The global topography of Mars and implications for surface evolution. Science 284, 1495–1503 (1999).

    Article  Google Scholar 

  11. Malin, M. C. & Edgett, K. E. Evidence for recent groundwater seepage and surface runoff on Mars. Science 288, 2330–2335 (2000).

    Article  Google Scholar 

  12. Dundas, C. M. et al. Seasonal activity and morphological changes in Martian gullies. Icarus 220, 124–143 (2012).

    Article  Google Scholar 

  13. Christensen, P. R. et al. The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey Mission. Space Sci. Rev. 110, 85–130 (2004).

    Article  Google Scholar 

  14. Schorghofer, N., Aharonson, O. & Khatiwala, S. Slope streaks on Mars: Correlations with surface properties and the potential role of water. Geophys. Res. Lett. 29, 2126 (2002).

    Google Scholar 

  15. Hansen, C. et al. Seasonal erosion and restoration of Mars’ Northern Polar Dunes. Science 331, 283–295 (2011).

    Article  Google Scholar 

  16. Ayoub, F., Bridges, N. T., Avouac, J-P., Leprince, S. & Lucas, A. 3rd Int. Planetary Dunes Workshop. LPI Contribution, 1673, 1–2 (LPI, 2012).

  17. Murchie, S. L. et al. Compact reconnaissance imaging spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO). J. Geophys. Res. 112, E05S03 (2007).

    Article  Google Scholar 

  18. Massé, M. et al. Nature and origin of RSL: Spectroscopy and detectability of liquid brines in the near-infrared. Lunar Planet. Sci. Conf. 43, 1856 (2012).

    Google Scholar 

  19. Pommerol, A. et al. Photometric properties of Mars soils analogs. J. Geophys. Res. Planets 118, 2045–2072 (2013).

    Article  Google Scholar 

  20. Byrne, S. et al. Distribution of mid-latitude ground ice on Mars from new impact craters. Science 325, 1674–1678 (2008).

    Article  Google Scholar 

  21. Dundas, C. M. et al. Observations of ice-exposing impacts on Mars over three Mars years. AGU Fall Meeting abstr. P31C-07 (2013).

  22. Mellon, M. T., Feldman, W. C. & Prettyman, T. H. The presence and stability of ground ice in the southern hemisphere of Mars. Icarus 169, 324–340 (2004).

    Article  Google Scholar 

  23. Burt, D. M. & Knauth, L. P. Electrically conducting, Ca-rich brines, rather than water, expected in the Martian subsurface. J. Geophys. Res. 108, 8026 (2003).

    Article  Google Scholar 

  24. Levy, J. S. Hydrological characteristics of recurrent slope lineae on Mars: Evidence for liquid flow through regolith and comparisons with Antarctic terrestrial analogs. Icarus 219, 1–4 (2012).

    Article  Google Scholar 

  25. Dickson, J. L., Head, J. W., Levy, J. S., Marchant, D. R. & Don Juan, Pond Antarctica: Near-surface CaCl2-brine feeding Earth’s most saline lake and implications for Mars. Sci. Rep. 3, 1–7 (2013).

    Google Scholar 

  26. Toigo, A. D., Smith, M. D., Seelos, F. P. & Murchie, S. L. High spatial and temporal resolution sampling of Martian gas abundances from CRISM spectra. J. Geophys. Res. 118, 89–104 (2013).

    Article  Google Scholar 

  27. Smith, M. D. Interannual variability in TES atmospheric observations of Mars during 1999–2003. Icarus 167, 148–165 (2004).

    Article  Google Scholar 

  28. Clancy, R. T. et al. An intercomparison of ground-based millimeter, MGS TES, and Viking atmospheric temperature measurements: Seasonal and interannual variability of temperatures and dust loading in the global Mars atmosphere. J. Geophys. Res. 105, 9553–9571 (2000).

    Article  Google Scholar 

  29. Gough, R. V., Chevrier, V. F., Baustian, K. J., Wise, M. E. & Tolbert, M. A. Laboratory studies of perchlorate phase transitions: Support for metastable aqueous perchlorate solutions on Mars. Earth Planet. Sci. Lett. 312, 371–377 (2011).

    Article  Google Scholar 

  30. Mohlmann, D. T. F., Niemand, M., Formisano, V., Savijarvi, H. & Wolkenberg, P. Fog phenomena on Mars. Planet. Space Sci. 57, 1987–1992 (2009).

    Article  Google Scholar 

  31. Cantor, B. A., James, P. B., Caplinger, M. & Wolff, M. J. Martian dust storms: 1999 Mars Orbiter Camera observations. J. Geophys. Res. 106, 23653–23688 (2001).

    Article  Google Scholar 

  32. Goldspiel, J. M. & Squyres, S. W. Groundwater discharge and gully formation on martian slopes. Icarus 211, 238–258 (2011).

    Article  Google Scholar 

  33. Osterloo, M. M., Anderson, F. S., Hamilton, V. E. & Hynek, B. M. Geologic context of proposed chloride-bearing materials on Mars. J. Geophys. Res. 115, E10012 (2010).

    Article  Google Scholar 

  34. Ojha, L., Wray, J. J., McEwen, A. S. & Murchie, S. L. Spectral constraints on the nature and formation mechanism of recurring slope lineae. Geophys. Res. Lett.http://dx.doi.org/10.1002/2013GL057893 (2013).

  35. Kminek, G. et al. Report to the COSPAR Mars special region colloquium. Adv. Space Res. 46, 811–829 (2010).

    Article  Google Scholar 

  36. Stillman, D. E., Grimm, R. E., Michaels, T. I. & Harrison, K. P. Formation of recurrent slope lineae (RSL) by freshwater discharge of melted cold traps. Lunar Planet. Sci. Conf. 44, 1737 (2013).

    Google Scholar 

  37. Paige, D. A. et al. Concepts and Approaches for Mars Exploration. LPI Contribution, 1679, 4235 (LPI, 2012).

  38. Kirk, R. L. et al. Ultrahigh resolution topographic mapping of Mars with MRO HiRISE stereo images: Meter-scale slopes of candidate Phoenix landing sites. J. Geophys. Res. 113, E00A24 (2008).

    Article  Google Scholar 

  39. Christensen, P. R. et al. JMARS — A Planetary GIS. AGU Fall Meeting, #IN22A-06 (2009).

  40. Christensen, P. R. et al. Mars Global Surveyor Thermal Emission Spectrometer experiment: Investigation description and surface science results. J. Geophys. Res. 106, 23823–23872 (2001).

    Article  Google Scholar 

Download references

Acknowledgements

We thank the MRO and Mars Odyssey projects and science teams for returning a wealth of data, and we thank NASA for supporting extended mission science. P. R. Christensen provided constructive review comments. NASA’s MRO project and Mars Data Analysis Program supported this work.

Author information

Authors and Affiliations

  1. Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA

    Alfred S. McEwen, Sarah S. Mattson, Matthew Chojnacki & Shane Byrne

  2. US Geological Survey, Flagstaff, Arizona 86001, USA

    Colin M. Dundas

  3. Johns Hopkins University/Applied Physics Laboratory, Laurel, Maryland 20723, USA

    Anthony D. Toigo & Scott L. Murchie

  4. Georgia Institute of Technology, Atlanta, Georgia 30332, USA

    Lujendra Ojha & James J. Wray

  5. Physikalisches Institut, University of Bern, Bern, Switzerland

    Nicolas Thomas

Authors
  1. Alfred S. McEwen
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Colin M. Dundas
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sarah S. Mattson
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Anthony D. Toigo
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Lujendra Ojha
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. James J. Wray
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Matthew Chojnacki
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Shane Byrne
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Scott L. Murchie
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Nicolas Thomas
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

A.S.M. and C.M.D. planned many of the HiRISE observations to search for and monitor the equatorial RSL. Image analysis to locate and track candidate RSL was performed by A.S.M. with significant help from C.M.D. and L.O. S.S.M. led production of DTMs and orthorectified images. M.C. assisted with DTM production and measurements, RSL reconnaissance and image analysis. A.D.T. extracted column abundances of water vapour from the CRISM data. S.B. contributed the thermal analyses. S.L.M., J.J.W. and L.O. contributed to CRISM observations and compositional analyses. N.T. contributed photometric analyses. All authors contributed to discussions, interpretations and writing.

Corresponding author

Correspondence to Alfred S. McEwen.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 4447 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

McEwen, A., Dundas, C., Mattson, S. et al. Recurring slope lineae in equatorial regions of Mars. Nature Geosci 7, 53–58 (2014). https://doi.org/10.1038/ngeo2014

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo2014

This article is cited by

Search

Advanced 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