Abstract
Recent liquid water flow on Mars has been proposed based on geomorphological features, such as gullies. Recurring slope lineae — seasonal flows that are darker than their surroundings — are candidate locations for seeping liquid water on Mars today, but their formation mechanism remains unclear. Topographical analysis shows that the terminal slopes of recurring slope lineae match the stopping angle for granular flows of cohesionless sand in active Martian aeolian dunes. In Eos Chasma, linea lengths vary widely and are longer where there are more extensive angle-of-repose slopes, inconsistent with models for water sources. These observations suggest that recurring slope lineae are granular flows. The preference for warm seasons and the detection of hydrated salts are consistent with some role for water in their initiation. However, liquid water volumes may be small or zero, alleviating planetary protection concerns about habitable environments.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
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).
Gough, R. V., Chevrier, V. F. & Tolbert, M. A. Formation of liquid water at low temperatures via the deliquescence of calcium chloride: implications for Antarctica and Mars. Planet. Space Sci. 131, 79–87 (2016).
Martin-Torres, F. J. et al. Transient liquid water and water activity at Gale crater on Mars. Nat. Geosci. 8, 357–361 (2015).
Nuding, D. L. et al. Deliquescence and efflorescence of calcium perchlorate: an investigation of stable aqueous solutions relevant to Mars. Icarus 243, 420–428 (2014).
Malin, M. C. & Edgett, K. S. Evidence for recent groundwater seepage and surface runoff on Mars. Science 288, 2330–2335 (2000).
McEwen, A. S. et al. Seasonal flows on warm Martian slopes. Science 333, 740–743 (2011).
Dundas, C. M., Diniega, S. & McEwen, A. S. Long-term monitoring of Martian gully formation and evolution with MRO/HiRISE. Icarus 251, 244–263 (2015).
McEwen, A. S. et al. Recurring slope lineae in equatorial regions of Mars. Nat. Geosci. 7, 53–58 (2014).
Stillman, D. E., Michaels, T. I., Grimm, R. E. & Harrison, K. P. New observations of Martian southern mid-latitude recurring slope lineae (RSL) imply formation by freshwater subsurface flows. Icarus 233, 328–341 (2014).
Stillman, D. E., Michaels, T. I., Grimm, R. E. & Hanley, J. Observations and modeling of northern mid-latitude recurring slope lineae (RSL) suggest recharge by a present-day Martian briny aquifer. Icarus 265, 125–138 (2016).
Chojnacki, M. et al. Geologic context of recurring slope lineae in Melas and Coprates Chasmata, Mars. J. Geophys. Res. https://doi.org/10.1002/2015JE004991 (2016).
Stillman, D. E., Michaels, T. I. & Grimm, R. E. Characteristics of the numerous and widespread recurring slope lineae (RSL) in Valles Marineris, Mars. Icarus 285, 195–210 (2017).
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).
Levy, J. 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).
Grimm, R. E., Harrison, K. P. & Stillman, D. E. Water budgets of Martian recurring slope lineae. Icarus 233, 316–327 (2014).
Massé, M. et al. Spectroscopy and detectability of liquid brines on Mars. Planet. Space Sci. 92, 136–149 (2014).
Schmidt, F., Andrieu, F., Costard, F., Kocifaj, M. & Meresescu, A. G. Formation of recurring slope lineae on Mars by rarefied gas-triggered granular flows. Nat. Geosci. 10, 270–274 (2017).
Edwards, C. S. & Piqueux, S. The water content of recurring slope lineae on Mars. Geophys. Res. Lett. https://doi.org/10.1002/2016GL070179 (2016).
Ojha, L. et al. Spectral evidence for hydrated salts in recurring slope lineae on Mars. Nat. Geosci. 8, 829–833 (2015).
Mitchell, J. L. & Christensen, P. R. Recurring slope lineae and chlorides on the surface of Mars. J. Geophys. Res. Planets 121, 1411–1428 (2016).
Martinez, G. M. & Renno, N. O. Water and brines on Mars: current evidence and implications for MSL. Space Sci. Rev. 175, 29–51 (2013).
Ingersoll, A. P. Mars: occurrence of liquid water. Science 168, 972–973 (1970).
Atwood-Stone, C. & McEwen, A. S. Avalanche slope angles in low-gravity environments from active Martian sand dunes. Geophys. Res. Lett. 40, 2929–2934 (2013).
Ojha, L. et al. HiRISE observations of recurring slope lineae (RSL) during southern summer on Mars. Icarus 231, 365–376 (2014).
Conway, S. J., Balme, M. R., Kreslavsky, M. A., Murray, J. B. & Towner, M. C. The comparison of topographic long profiles of gullies on Earth to gullies on Mars: a signal of water on Mars. Icarus 253, 189–204 (2016).
Ayoub, F. et al. Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux. Nat. Commun. 5, 5096 (2014).
Daubar, I. J. et al. Changes in blast zone albedo patterns around new Martian impact craters. Icarus 267, 86–105 (2016).
Wells, E. N., Veverka, J. & Thomas, P. Mars: experimental study of albedo changes caused by dust fallout. Icarus 58, 331–338 (1984).
Leighton, R. B. & Murray, B. C. Behavior of carbon dioxide and other volatiles on Mars. Science 153, 136–144 (1966).
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).
Möhlmann, D. T. F. & Thomsen, K. Properties of cryobrines on Mars. Icarus 212, 123–130 (2011).
Toner, J. D. & Catling, D. C. Water activities of NaClO4, Ca(ClO4)2, and Mg(ClO4)2 brines from experimental heat capacities: water activity >0.6 below 200 K. Geochim. Cosmochim. Acta 181, 164–174 (2016).
MARSTHERM thermal model. https://marstherm.boulder.swri.edu/index.php, run 29 November 2016.
Zent, A. P., Hecht, M. H., Hudson, T. L., Wood, S. E. & Chevrier, V. F. A revised calibration function and results for the Phoenix mission TECP relative humidity sensor. J. Geophys. Res. https://doi.org/10.1002/2015JE004933 (2016).
Wang, A. et al. Atmosphere–surface H2O exchange to sustain the Recurring Slope Lineae (RSL) on Mars. Lunar Planet. Sci. Conf. 48, 2351 (2017).
Kossacki, K. J. & Markiewicz, W. J. Seasonal flows on dark Martian slopes, thermal condition for liquescence of salts. Icarus 233, 126–130 (2014).
Farrell, W. M. et al. Is the Martian water table hidden from radar view? Geophys. Res. Lett. https://doi.org/10.1029/2009GL038945 (2009).
Stillman, D. E. & Grimm, R. E. Radar penetrates only the youngest geologic units on Mars. J. Geophys. Res. 116, E03001 (2011).
Andrews-Hanna, J. C., Zuber, M. T., Arvidson, R. E. & Wiseman, S. M. Early Mars hydrology: Meridiani playa deposits and the sedimentary record of Arabia Terra. J. Geophys. Res. https://doi.org/10.1029/2009JE003485 (2010).
Massé, M. et al. Transport processes induced by metastable boiling water under Martian surface conditions. Nat. Geosci. 9, 425–428 (2016).
Arvidson, R. E., Gooding, J. L. & Moore, H. J. The Martian surface as imaged, sampled, and analyzed by the Viking landers. Rev. Geophys. 27, 39–60 (1989).
McDonald, R. R. & Anderson, R. S. Constraints on eolian grain flow dynamics through laboratory experiments on sand slopes. J. Sediment. Res. 66, 642–653 (1996).
Takagi, D., McElwaine, J. N. & Huppert, H. E. Shallow granular flows. Phys. Rev. E 83, 031306 (2011).
Ewing, R. C. et al. Sedimentary processes at the Bagnold Dunes: implications for the eolian rock record of Mars. J. Geophys. Res. Planets https://doi.org/10.1002/2017JE005324 (in the press).
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).
Christensen, P. R. et al. Mars Global Surveyor Thermal Emission Spectrometer experiment: investigation description and surface science results. J. Geophys. Res. 106, 23823–23871 (2001).
Kinch, K. M. et al. Dust deposition on the decks of the Mars Exploration Rovers: 10 years of dust dynamics on the Panoramic Camera calibration targets. Earth Space Sci. 2, 144–172 (2015).
Lapotre, M. G. A. et al. Large wind ripples on Mars: a record of atmospheric evolution. Science 353, 55–58 (2016).
Greeley, R. & Iverson, J. D. Wind as a Geologic Process (Cambridge Univ. Press, Cambridge, 1985).
Ojha, L. et al. Spectral constraints on the formation mechanism of recurring slope lineae. Geophys. Res. Lett. https://doi.org/10.1002/2013GL057893 (2013).
Möhlmann, D. T. F. The influence of van der Waals forces on the state of water in the shallow subsurface of Mars. Icarus 195, 131–139 (2008).
Sizemore, H. G., Zent, A. P. & Rempel, A. W. Initiation and growth of Martian ice lenses. Icarus 251, 191–210 (2015).
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).
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).
McEwen, A. S. et al. Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE). J. Geophys. Res. https://doi.org/10.1029/2005JE002605 (2007).
Schaefer, E. I., McEwen, A. S., Mattson, S. & Ojha, L. Quantifying the behavior of recurring slope lineae (RSL). Lunar Planet. Sci. Conf. 46, 2930 (2015).
Acknowledgements
Observation planning was funded by the MRO project, and analysis by NASA grants NNX13AK01G and NNX14AO21G. We thank NASA/JPL/University of Arizona and the MRO/HiRISE project for collecting and processing data, the University of Arizona for producing DTMs, and NASA for supporting extended mission investigations. D. Stillman provided helpful comments.
Author information
Authors and Affiliations
Contributions
A.S.M., C.M.D. and M.C. planned many of the HiRISE observations to locate and study RSL. C.M.D. designed the study and gathered the slope data. A.O. and M.C. made observations of uphill ripple movement. M.C. assisted with DTM production. All authors contributed to discussion, interpretation and writing.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Additional information
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Electronic supplementary material
GranularRSL_SOM
Supplementary Table 1; Supplementary Figures S1–S4; and caption information for the supplementary Movies 1–2 animations provided as separate files. (Animations S1–S2)
Animation1_Dune_avalanche_lineae_27N.gif
Animated GIF showing avalanche features on a sand dune slipface, to be compared with RSL
Animation2_Coprates_ripples.gif
Animated GIF showing upslope movement of ripples at one RSL location
Rights and permissions
About this article
Cite this article
Dundas, C.M., McEwen, A.S., Chojnacki, M. et al. Granular flows at recurring slope lineae on Mars indicate a limited role for liquid water. Nature Geosci 10, 903–907 (2017). https://doi.org/10.1038/s41561-017-0012-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41561-017-0012-5
This article is cited by
-
Coupling and interactions across the Martian whole atmosphere system
Nature Geoscience (2023)
-
Terrestrial Martian Analog Heritage of Kachchh Basin, Western India
Geoheritage (2022)
-
Extraterrestrial Life Signature Detection Microscopy: Search and Analysis of Cells and Organics on Mars and Other Solar System Bodies
Space Science Reviews (2022)
-
Geomorphological evidence for a dry dust avalanche origin of slope streaks on Mars
Nature Geoscience (2020)
-
Methanogenic Archaea Can Produce Methane in Deliquescence-Driven Mars Analog Environments
Scientific Reports (2020)