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.

Spectral evidence for hydrated salts in recurring slope lineae on Mars

A Corrigendum to this article was published on 29 October 2015

This article has been updated

Abstract

Determining whether liquid water exists on the Martian surface is central to understanding the hydrologic cycle and potential for extant life on Mars. Recurring slope lineae, narrow streaks of low reflectance compared to the surrounding terrain, appear and grow incrementally in the downslope direction during warm seasons when temperatures reach about 250–300 K, a pattern consistent with the transient flow of a volatile species1,2,3. Brine flows (or seeps) have been proposed to explain the formation of recurring slope lineae1,2,3, yet no direct evidence for either liquid water or hydrated salts has been found4. Here we analyse spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars instrument onboard the Mars Reconnaissance Orbiter from four different locations where recurring slope lineae are present. We find evidence for hydrated salts at all four locations in the seasons when recurring slope lineae are most extensive, which suggests that the source of hydration is recurring slope lineae activity. The hydrated salts most consistent with the spectral absorption features we detect are magnesium perchlorate, magnesium chlorate and sodium perchlorate. Our findings strongly support the hypothesis that recurring slope lineae form as a result of contemporary water activity on Mars.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Palikir crater RSL and spectral detection of hydration features.
Figure 2: RSL activity in the central peaks of Horowitz crater and associated CRISM spectra.
Figure 3: RSL emanating from a central peak in Hale crater and associated CRISM spectrum.
Figure 4: RSL and associated dark fans observed in Coprates Chasma and associated CRISM spectra.

Change history

  • 14 October 2015

    In the version of this Letter originally published, the journal name in ref. 12 was incorrect, it should have been Nature Geoscience. This has been corrected in all versions of the Letter.

References

  1. McEwen, A. S. et al. Seasonal flows on warm Martian slopes. Science 333, 740–743 (2011).

    Article  Google Scholar 

  2. McEwen, A. S. et al. Recurring slope lineae in equatorial regions of Mars. Nature Geosci. 7, 53–58 (2014).

    Article  Google Scholar 

  3. Ojha, L. et al. HiRISE observations of recurring slope lineae (RSL) during southern summer on Mars. Icarus 231, 365–376 (2014).

    Article  Google Scholar 

  4. Ojha, L. et al. Spectral constraints on the formation mechanism of recurring slope lineae. Geophys. Res. Lett. 40, 5621–5626 (2013).

    Article  Google Scholar 

  5. Hecht, M. H. et al. Detection of perchlorate and the soluble chemistry of martian soil at the Phoenix lander site. Science 325, 64–67 (2009).

    Article  Google Scholar 

  6. Glavin, D. P. et al. Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater. J. Geophys. Res. 118, 1955–1973 (2013).

    Article  Google Scholar 

  7. Ehlmann, B. L. & Edwards, C. S. Mineralogy of the Martian surface. Annu. Rev. Earth Planet. Sci. 42, 291–315 (2015).

    Article  Google Scholar 

  8. Pestova, O. N., Myund, L. A., Khripun, M. K. & Prigaro, A. V. Polythermal study of the systems M(ClO4)2-H2O (M2+ = Mg2+, Ca2+, Sr2+, Ba2+). Russ. J. Appl. Chem. 78, 409–413 (2005).

    Article  Google Scholar 

  9. Chevrier, V. F., Hanley, J. & Altheide, T. S. Stability of perchlorate hydrates and their liquid solutions at the Phoenix landing site, Mars. Geophys. Res. Lett. 36, L10202 (2009).

    Article  Google Scholar 

  10. Hanley, J., Chevrier, V. F., Berget, D. J. & Adams, R. D. Chlorate salts and solutions on Mars. Geophys. Res. Lett. 39, L08201 (2012).

    Google Scholar 

  11. Altheide, T., Cheverier, V. F., Nicholson, C. & Denson, J. Experimental investigation of the stability and evaporation of sulfate and chloride brines on Mars. Earth Planet. Sci. Lett. 282, 69–78 (2009).

    Article  Google Scholar 

  12. Martín-Torres, F. J. et al. Transient liquid water and water activity at Gale crater on Mars. Nature Geosci. 8, 357–361 (2015).

    Article  Google Scholar 

  13. McEwen, A. S. et al. Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE). J. Geophys. Res. 112, 1991–2012 (2007).

    Article  Google Scholar 

  14. Murchie, S. et al. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO). J. Geophys. Res. 112, 1–57 (2007).

    Article  Google Scholar 

  15. Clark, R. N. in Manual of Remote Sensing, Volume 3, Remote Sensing for the Earth Sciences (ed. Rencz, A. N.) 3–58 (John Wiley, 1999).

    Google Scholar 

  16. Massé, M. et al. Spectroscopy and detectability of liquid brines on Mars. Planet. Space Sci. 92, 136–149 (2014).

    Article  Google Scholar 

  17. Hanley, J. et al. Reflectance spectra of hydrated chlorine salts: The effect of temperature with implications for Europa. J. Geophys. Res. 119, 2370–2377 (2014).

    Article  Google Scholar 

  18. Bishop, J. L., Quinn, R. & Darby, D. M. Spectral and thermal properties of perchlorate salts and implications for Mars. Am. Mineral. 99, 1580–1592 (2014).

    Article  Google Scholar 

  19. Rummel, J. D. et al. A new analysis of Mars “Special Regions”: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2). Astrobiology 14, 887–968 (2014).

    Article  Google Scholar 

  20. 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 

  21. Navarro-Gonzalez, R., Vargas, E., Rosa, J., Raga, A. C. & McKay, C. P. Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars. J. Geophys. Res. 115, E12010 (2010).

    Article  Google Scholar 

  22. Elsenousy, A., Hanley, J. & Chevrier, V. F. Effect of evaporation and freezing on the salt paragenesis and habitability of brines at the Phoenix landing site. Earth Planet. Sci. Lett. 421, 39–46 (2015).

    Article  Google Scholar 

  23. Kounaves, S., Carrier, B. L., O’Neil, G. D., Stroble, S. T. & Claire, M. W. Evidence of Martian perchlorate, chlorate and nitrate in Mars meteorite EETA79001: Implications for oxidants and organics. Icarus 229, 206–213 (2014).

    Article  Google Scholar 

  24. 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 

  25. Davila, A. F. et al. Facilitation of endolithic microbial survival in the hyperarid core of the Atacama Desert by mineral deliquescence. J. Geophys. Res. 113, 2005–2012 (2008).

    Article  Google Scholar 

  26. Davila, A. F., Hawes, I., Ascaso, C. & Wierzchos, J. Salt deliquescence drives photosynthesis in the hyperarid Atacama Desert. Environ. Microbiol. Rep. 5, 583–587 (2013).

    Article  Google Scholar 

  27. Aharon, O., Bardavid, R. E. & Mana, L. Perchlorate and halophilic prokaryotes: Implications for possible halophilic life on Mars. Extremophiles 18, 75–80 (2014).

    Article  Google Scholar 

  28. Hanley, J., Chevrier, V. F., Barrows, R. S., Swaffer, C. & Altheide, T. S. Near- and mid-infrared reflectance spectra of hydrated oxychlorine salts with implications for Mars. J. Geophys. Res. 120, 1415–1426 (2015).

    Article  Google Scholar 

  29. Crowley, J. K. Visible and near-infrared (0.4–2.5 μm) reflectance spectra of Playa evaporite minerals. J. Geophys. Res. 96, 16231–16240 (1991).

    Article  Google Scholar 

Download references

Acknowledgements

L.O. and M.B.W. are funded by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1148903. The research was further supported by MDAP Grant No. NNX13AK01G. All original data described in this paper are reported in the SOM and archived by NASA’s Planetary Data System. We thank the MRO science and engineering team for returning such an incredible data set. The paper benefited from initial reviews by B. Schmidt and L. Liuzzo.

Author information

Authors and Affiliations

Authors

Contributions

The methodology was conceived and designed by L.O. All data analysis was done by L.O. with significant feedback from S.L.M., J.J.W., A.S.M. and M.B.W. J.J.W., M.B.W., J.H. and M.M. provided all the laboratory spectra used in this paper. A.S.M., M.C. and S.L.M. planned many of the HiRISE–CRISM coordinated observations of the RSL sites. All authors contributed to discussion, interpretation and writing.

Corresponding author

Correspondence to Lujendra Ojha.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 3115 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ojha, L., Wilhelm, M., Murchie, S. et al. Spectral evidence for hydrated salts in recurring slope lineae on Mars. Nature Geosci 8, 829–832 (2015). https://doi.org/10.1038/ngeo2546

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo2546

Further reading

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