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.

An interval of high salinity in ancient Gale crater lake on Mars


Precipitated minerals, including salts, are primary tracers of atmospheric conditions and water chemistry in lake basins. Ongoing in situ exploration by the Curiosity rover of Hesperian (around 3.3–3.7 Gyr old) sedimentary rocks within Gale crater on Mars has revealed clay-bearing fluvio-lacustrine deposits with sporadic occurrences of sulfate minerals, primarily as late-stage diagenetic veins and concretions. Here we report bulk enrichments, disseminated in the bedrock, of 30–50 wt% calcium sulfate intermittently over about 150 m of stratigraphy, and of 26–36 wt% hydrated magnesium sulfate within a thinner section of strata. We use geochemical analysis, primarily from the ChemCam laser-induced breakdown spectrometer, combined with results from other rover instruments, to characterize the enrichments and their lithology. The deposits are consistent with early diagenetic, pre-compaction salt precipitation from brines concentrated by evaporation, including magnesium sulfate-rich brines from extreme evaporative concentration. This saline interval represents a substantial hydrological perturbation of the lake basin, which may reflect variations in Mars’ obliquity and orbital parameters. Our findings support stepwise changes in Martian climate during the Hesperian, leading to more arid and sulfate-dominated environments as previously inferred from orbital observations.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Stratigraphic context on bedrock composition.
Fig. 2: ChemCam oxide and elemental data of calcium and magnesium sulfate enrichments.
Fig. 3: Lithology of sulfate enrichments.
Fig. 4: Evaporation of surface brines and early diagenetic deposition.

Data availability

All in situ and orbital data used in this study are available in the NASA Planetary Data System ( Other supplementary data that support the findings of this study are available from the corresponding author on reasonable request.


  1. 1.

    Tosca, N. J. & McLennan, S. M. Chemical divides and evaporite assemblages on Mars. Earth Planet. Sci. Lett. 241, 21–31 (2006).

    Article  Google Scholar 

  2. 2.

    Clark, B. C. et al. Chemistry and mineralogy of outcrops at Meridiani Planum. Earth Planet. Sci. Lett. 240, 73–94 (2005).

    Article  Google Scholar 

  3. 3.

    Tosca, N. J. et al. Geochemical modeling of evaporation processes on Mars: insight from the sedimentary record at Meridiani Planum. Earth Planet. Sci. Lett. 240, 122–148 (2005).

    Article  Google Scholar 

  4. 4.

    Ehlmann, B. L. & Edwards, C. S. Mineralogy of the Martian surface. Annu. Rev. Earth Planet. Sci. 42, 291–315 (2014).

    Article  Google Scholar 

  5. 5.

    Bibring, J.-P. et al. Global mineralogical and aqueous Mars history derived from OMEGA/Mars express data. Science 312, 400–404 (2006).

    Article  Google Scholar 

  6. 6.

    Le Deit, L. et al. Sequence of infilling events in Gale Crater, Mars: results from morphology, stratigraphy, and mineralogy. J. Geophys. Res. Planets 118, 2439–2473 (2013).

    Article  Google Scholar 

  7. 7.

    Fraeman, A. A. et al. The stratigraphy and evolution of lower Mount Sharp from spectral, morphological, and thermophysical orbital data sets. J. Geophys. Res. Planets 121, 1713–1736 (2016).

    Article  Google Scholar 

  8. 8.

    Milliken, R. E., Grotzinger, J. P. & Thomson, B. J. Paleoclimate of Mars as captured by the stratigraphic record in Gale Crater. Geophys. Res. Lett. 37, (2010).

  9. 9.

    Grotzinger, J. P. et al. Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars. Science 350, aac7575 (2015).

    Article  Google Scholar 

  10. 10.

    Hurowitz, J. A. et al. Redox stratification of an ancient lake in Gale crater, Mars. Science 356, eaah6849 (2017).

    Article  Google Scholar 

  11. 11.

    McLennan, S. M. et al. Elemental geochemistry of sedimentary rocks at Yellowknife Bay, Gale Crater, Mars. Science 343, 1244734 (2014).

    Article  Google Scholar 

  12. 12.

    Bristow, T. F. et al. Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars. Sci. Adv. 4, eaar3330 (2018).

    Article  Google Scholar 

  13. 13.

    Nachon, M. et al. Calcium sulfate veins characterized by ChemCam/Curiosity at Gale crater, Mars. J. Geophys. Res. Planets 119, 2013JE004588 (2014).

    Article  Google Scholar 

  14. 14.

    Rapin, W. et al. Hydration state of calcium sulfates in Gale crater, Mars: identification of bassanite veins. Earth Planet. Sci. Lett. 452, 197–205 (2016).

    Article  Google Scholar 

  15. 15.

    Kah, L. C., Stack, K. M., Eigenbrode, J. L., Yingst, R. A. & Edgett, K. S. Syndepositional precipitation of calcium sulfate in Gale Crater, Mars. Terra Nova 30, 431–439 (2018).

    Article  Google Scholar 

  16. 16.

    Nachon, M. et al. Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars. Icarus 281, 121–136 (2017).

    Article  Google Scholar 

  17. 17.

    VanBommel, S. J. et al. Deconvolution of distinct lithology chemistry through oversampling with the Mars Science Laboratory Alpha Particle X-Ray Spectrometer. Xray Spectrom. 45, 155–161 (2016).

    Article  Google Scholar 

  18. 18.

    Mangold, N. et al. Chemical alteration of fine-grained sedimentary rocks at Gale crater. Icarus 321, 619–631 (2019).

    Article  Google Scholar 

  19. 19.

    Anderson, D. E. et al. Characterization of LIBS emission lines for the identification of chlorides, carbonates, and sulfates in salt/basalt mixtures for the application to MSL ChemCam data. J. Geophys. Res. Planets 122, 744–770 (2017).

    Article  Google Scholar 

  20. 20.

    Stack, K. M. et al. Evidence for plunging river plume deposits in the Pahrump Hills member of the Murray formation, Gale crater, Mars. Sedimentology 0, (2018).

  21. 21.

    Rapin, W. et al. Quantification of water content by laser induced breakdown spectroscopy on Mars. Spectrochim. Acta Part B At. Spectrosc. 130, 82–100 (2017).

    Article  Google Scholar 

  22. 22.

    Rivera-Hernández, F. et al. Using ChemCam LIBS data to constrain grain size in rocks on Mars: proof of concept and application to rocks at Yellowknife Bay and Pahrump Hills, Gale crater. Icarus 321, 82–98 (2019).

    Article  Google Scholar 

  23. 23.

    Warren, J. K. Evaporites: Sediments, Resources and Hydrocarbons (Springer Science & Business Media, 2006).

  24. 24.

    Handford, C. R. in Developments in Sedimentology, Vol. 50 (ed. Melvin, J. L.) 1–66 (Elsevier, 1991).

  25. 25.

    Giles, M. R. Diagenesis: A Quantitative Perspective: Implications for Basin Modelling and Rock Property Prediction (Kluwer Academic, 1997).

  26. 26.

    Chipera, S. J. & Vaniman, D. T. Experimental stability of magnesium sulfate hydrates that may be present on Mars. Geochim. Cosmochim. Acta 71, 241–250 (2007).

    Article  Google Scholar 

  27. 27.

    Holliday, D. W. The petrology of secondary gypsum rocks: a review. J. Sediment. Res. 40, 734–744 (1970).

    Article  Google Scholar 

  28. 28.

    Vaniman, D. T. et al. Gypsum, bassanite, and anhydrite at Gale crater, Mars. Am. Mineral. 103, 1011–1020 (2018).

    Article  Google Scholar 

  29. 29.

    Schieber, J. et al. Encounters with an unearthly mudstone: understanding the first mudstone found on Mars. Sedimentology 64, 311–358 (2017).

    Article  Google Scholar 

  30. 30.

    Gustavson, T. C., Hovorka, S. D. & Dutton, A. R. Origin of satin spar veins in evaporite basins. J. Sediment. Res. 64, 88–94 (1994).

    Google Scholar 

  31. 31.

    Thomas, N. H. et al. Mars Science Laboratory Observations of Chloride Salts in Gale Crater, Mars. Geographic. Res. Lett. (2019).

  32. 32.

    Wang, A., Freeman, J. J. & Jolliff, B. L. Phase transition pathways of the hydrates of magnesium sulfate in the temperature range 50°C to 5°C: implication for sulfates on Mars. J. Geophys. Res. Planets 114, E04010 (2009).

    Google Scholar 

  33. 33.

    Vaniman, D. T. & Chipera, S. J. Transformations of Mg- and Ca-sulfate hydrates in Mars regolith. Am. Mineral. 91, 1628–1642 (2006).

    Article  Google Scholar 

  34. 34.

    Stein, N. et al. Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale Crater. Geology 46, 515–518 (2018).

    Article  Google Scholar 

  35. 35.

    Chemcam passive reflectance spectroscopy of recent drill tailings, hematite-bearing rocks, and dune sands. in 47, 1155 (2016).

  36. 36.

    Tosca, N. J., Ahmed, I. A. M., Tutolo, B. M., Ashpitel, A. & Hurowitz, J. A. Magnetite authigenesis and the warming of early Mars. Nat. Geosci. 11, 635 (2018).

    Article  Google Scholar 

  37. 37.

    Cabestrero, Ó., del Buey, P. & Sanz-Montero, M. E. Biosedimentary and geochemical constraints on the precipitation of mineral crusts in shallow sulphate lakes. Sediment. Geol. 366, 32–46 (2018).

    Article  Google Scholar 

  38. 38.

    Kilmer, B. R. et al. Molecular and phenetic characterization of the bacterial assemblage of Hot Lake, WA, an environment with high concentrations of magnesium sulfate, and its relevance to Mars. Int. J. Astrobiol. 13, 69–80 (2014).

    Article  Google Scholar 

  39. 39.

    Pontefract, A. et al. Microbial diversity in a hypersaline sulfate lake: a terrestrial analog of ancient Mars. Front. Microbiol. 8, 1819 (2017).

    Article  Google Scholar 

  40. 40.

    Aubrey, A. et al. Sulfate minerals and organic compounds on Mars. Geology 34, 357–360 (2006).

    Article  Google Scholar 

  41. 41.

    Fedo, C. et al. Sedimentology and stratigraphy of the Murray formation, Gale crater, Mars. In 49th Lunar and Planetary Science Conference 2018, 2078 (Lunar Planetary Institute, 2018).

  42. 42.

    Schieber, J. et al. A sand-lens in the upper Murray formation at Gale crater, Mars: a likely lowstand deposit of a dynamic ancient lake. in 48, 2311 (2017).

  43. 43.

    Laskar, J. et al. Long term evolution and chaotic diffusion of the insolation quantities of Mars. Icarus 170, 343–364 (2004).

    Article  Google Scholar 

  44. 44.

    Grotzinger, J. P. et al. Mars Science Laboratory mission and science investigation. Space Sci. Rev. 170, 5–56 (2012).

    Article  Google Scholar 

  45. 45.

    Mitrofanov, I. et al. Studying of water consent in Mars’ gale crater: the first results of the DAN experiment on the NASA curiosity rover. Dokl. Phys. 59, 126–128 (2014).

    Article  Google Scholar 

  46. 46.

    Maurice, S. et al. The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover: science objectives and mast unit description. Space Sci. Rev. 170, 95–166 (2012).

    Article  Google Scholar 

  47. 47.

    Wiens, R. C. et al. The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover: body unit and combined system tests. Space Sci. Rev. 170, 167–227 (2012).

    Article  Google Scholar 

  48. 48.

    Clegg, S. M. et al. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database. Spectrochim. Acta Part B 129, 64–85 (2017).

    Article  Google Scholar 

  49. 49.

    Dyar, M. D. et al. Strategies for Mars remote laser-induced breakdown spectroscopy analysis of sulfur in geological samples. Spectrochim. Acta Part B 66, 39–56 (2011).

    Article  Google Scholar 

  50. 50.

    Schröder, S., Pavlov, S. G., Rauschenbach, I., Jessberger, E. K. & Hübers, H.-W. Detection and identification of salts and frozen salt solutions combining laser-induced breakdown spectroscopy and multivariate analysis methods: a study for future Martian exploration. Icarus 223, 61–73 (2013).

    Article  Google Scholar 

  51. 51.

    Sobron, P., Wang, A. & Sobron, F. Extraction of compositional and hydration information of sulfates from laser-induced plasma spectra recorded under Mars atmospheric conditions—implications for ChemCam investigations on Curiosity rover. Spectrochim. Acta Part B 68, 1–16 (2012).

    Article  Google Scholar 

  52. 52.

    McGuire, P. C. et al. An improvement to the volcano-scan algorithm for atmospheric correction of CRISM and OMEGA spectral data. Planet. Space Sci. 57, 809–815 (2009).

    Article  Google Scholar 

  53. 53.

    Stamnes, K., Tsay, S., Wiscombe, W. & Jayaweera, K. Numerically stable algorithm for discrete-ordinate-method radiative transfer in multiple scattering and emitting layered media. Appl. Opt. 27, 2502–2509 (1988).

    Article  Google Scholar 

  54. 54.

    He, L., O’Sullivan, J. A., Politte, D. V., Powell, K. E. & Arvidson, R. E. Quantitative reconstruction and denoising method HyBER for hyperspectral image data and its application to CRISM. IEEE J. STARS 12, 1219–1230 (2019).

    Google Scholar 

  55. 55.

    Cloutis, E. A. et al. Detection and discrimination of sulfate minerals using reflectance spectroscopy. Icarus 184, 121–157 (2006).

    Article  Google Scholar 

Download references


Thanks to the MSL operations team for their dedication in generating this dataset, and to the LANL team for collection of data to support sulfur calibration. Thanks to J. Grotzinger, C. Fedo, K. Siebach, L. Edgar and other members of the informal MSL Sed-Strat group for discussions that helped improve this work. The authors also thank S. Clegg and other members of the ChemCam team for discussions on sulfur signal calibration. W.R. and B.L.E. were funded by a MSL Participating Scientist grant NNN12AA01C. The work of G.D. was supported by the CNES through the ChemCam Program. This work and the MSL project are supported by the NASA Mars Exploration Program.

Author information




W.R. analysed the LIBS and image data and conceived and wrote the manuscript. W.R., B.L.E. and G.D. conceived and revised the manuscript. J.S., W.W.F., B.C.C., L.C.K., N.M., R.C.W. and A.R.V., contributed to the interpretation of the data and revisions of the manuscript. N.H.T. provided LIBS chloride peak analyses. V.K.F. analysed CRISM signatures of hydrated sulfates. N.T.S. and F.R.H. provided grain size estimates from Mars Hand Lens Imager (MAHLI) images of Murray bedrock. M.N. and H.A.M. identified and mapped sulfate vein occurrences. L.T. analysed APXS data of Murray bedrock. T.S.J.G. and C.H. provided DAN data analysis.

Corresponding author

Correspondence to W. Rapin.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Primary handling editor(s): Stefan Lachowycz.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–15 and Supplementary Tables 1–3.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Rapin, W., Ehlmann, B.L., Dromart, G. et al. An interval of high salinity in ancient Gale crater lake on Mars. Nat. Geosci. 12, 889–895 (2019).

Download citation

Further reading


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