The detection of liquid water by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) at the base of the south polar layered deposits in Ultimi Scopuli has reinvigorated the debate about the origin and stability of liquid water under present-day Martian conditions. To establish the extent of subglacial water in this region, we acquired new data, achieving extended radar coverage over the study area. Here, we present and discuss the results obtained by a new method of analysis of the complete MARSIS dataset, based on signal processing procedures usually applied to terrestrial polar ice sheets. Our results strengthen the claim of the detection of a liquid water body at Ultimi Scopuli and indicate the presence of other wet areas nearby. We suggest that the waters are hypersaline perchlorate brines, known to form at Martian polar regions and thought to survive for an extended period of time on a geological scale at below-eutectic temperatures.
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Data reported in this paper are available through the Zenodo research data repository (https://zenodo.org/record/3948005).
The code used to produce the figures and numerical results stated in the text is available from the corresponding author on reasonable request.
Laskar, J. et al. Long term evolution and chaotic diffusion of the insolation quantities of Mars. Icarus 170, 343–364 (2004).
Murray, B. C., Ward, W. R. & Yeung, S. C. Periodic insolation variations on Mars. Science 180, 638–640 (1973).
Ward, W. R. Large-scale variations in the obliquity of Mars. Science 181, 260–262 (1973).
Ward, W. R. in Mars (eds Kieffer, H. H. et al.) 298–320 (Univ. Arizona Press, 1992).
Laskar, J., Levrard, B. & Mustard, J. F. Orbital forcing of the Martian polar layered deposits. Nature 419, 375–377 (2002).
Byrne, S. The polar deposits of Mars. Annu. Rev. Earth Planet. Sci. 37, 535–560 (2009).
Guallini, L. et al. Regional stratigraphy of the south polar layered deposits (Promethei Lingula, Mars): “discontinuity-bounded” units in images and radargrams. Icarus 308, 76–107 (2018).
Smith, I. B. et al. 6th International Conference on Mars Polar Science and Exploration: conference summary and five top questions. Icarus 308, 2–14 (2018).
Phillips, R. J. et al. Mars north polar deposits: stratigraphy, age, and geodynamical response. Science 320, 1182–1185 (2008).
Head, J. W. & Pratt, S. Extensive Hesperian-aged south polar ice sheet on Mars: evidence for massive melting and retreat, and lateral flow and ponding of meltwater. J. Geophys. Res. 106, 12275–12299 (2001).
Fastook, J. L., Head, J. W., Marchant, D. R., Forget, F. & Madeleine, J.-B. Early Mars climate near the Noachian–Hesperian boundary: independent evidence for cold conditions form basal melting of the south polar ice sheet (Dorsa Argentea Formation) and implications for valley network formation. Icarus 219, 25–40 (2012).
Grott, M. et al. Long-term evolution of the Martian crust-mantle system. Space Sci. Rev. 174, 49–111 (2013).
Grima, C. et al. Large asymmetric polar scarps on Planum Australia, Mars: characterization and evolution. Icarus 212, 96–109 (2011).
Guallini, L., Brozzetti, F. & Marinangeli, L. Large-scale deformational systems in the South Polar Layered Deposits (Promethei Lingula, Mars): “soft-sediment” and deep-seated gravitational slope deformations mechanisms. Icarus 220, 821–843 (2012).
Guallini, L. et al. “Unconformity-bounded” stratigraphic units in the South Polar Layered Deposits (Promethei Lingula, Mars). In STRATI 2013 331–335 (Springer, 2014).
Wieczorek, M. A. Constraints on the composition of the Martian south polar cap from gravity and topography. Icarus 196, 506–517 (2008).
Fisher, D. A., Hecht, M. H., Kounaves, S. P. & Catling, D. C. A perchlorate brine lubricated deformable bed facilitating flow on the north polar cap of Mars: possible mechanism for water table recharging. J. Geophys. Res. 115, E00E12 (2010).
Sori, M. M. & Bramson, A. M. Water on Mars, with a grain of salt: local heat anomalies are required for basal melting of ice at the south pole today. Geophys. Res. Lett. 46, 1222–1231 (2019).
Hamilton, C. W., Fagents, S. A. & Wilson, L. Explosive lava-water interactions in Elysium Planitia, Mars: geologic and thermodynamic constraints on the formation of the Tartarus Colles cone groups. J. Geophys. Res. 115, E09006 (2010).
Horvath, D. G. & Andrews-Hanna, J. C. The thickness and morphology of a young pyroclastic deposit in Cerberus Palus, Mars: implications for the formation sequence. In 49th Lunar Planet. Sci. Conference Abstract number 2435 (Lunar and Planetary Institute, 2018).
Souček, O., Bourgeois, O., Pochat, S. & Guidat, T. A 3 Ga old polythermal ice sheet in Isidis Planitia, Mars: dynamics and thermal regime inferred from numerical modeling. Earth Planet. Sci. Lett. 426, 176–190 (2015).
Siegert, M. J. A 60-year international history of Antarctic subglacial lake exploration. J. Geol. Soc. Lond. 461, 7–21 (2018).
Picardi, G. et al. Radar soundings of the subsurface of Mars. Science 310, 1925–1928 (2005).
Clifford, S. M. et al. Depth of the Martian cryosphere: revised estimates and implications for the existence and detection of subpermafrost groundwater. J. Geophys. Res. 115, E07001 (2010).
Lasue, J., Clifford, S. M., Conway, S. J., Mangold, N. & Butcher, F. E. in Volatiles in the Martian Crust 185–246 (Elsevier, 2019).
Orosei, R. et al. Radar evidence of subglacial liquid water on Mars. Science 361, 490–493 (2018).
Oswald, G. K. A. & Gogineni, S. P. Recovery of subglacial water extent from Greenland radar survey data. J. Glaciol. 54, 94–106 (2008).
Carter, S. P. et al. Radar-based subglacial lake classification in Antarctica. Geochem. Geophys. Geosys. 8, Q03016 (2007).
Young, D. A., Schroeder, D. M., Blankenship, D. D., Kempf, S. D. & Quartini, E. The distribution of basal water between Antarctic subglacial lakes from radar sounding. Phil. Trans. R. Soc. A 374, 20140297 (2016).
Palmer, S. J. et al. Greenland subglacial lakes detected by radar. Geophys. Res. Lett. 40, 6154–6159 (2013).
Bowling, J. S., Livingstone, S. J., Sole, A. J. & Chu, W. Distribution and dynamics of Greenland subglacial lakes. Nat. Commun. 10, 2810 (2019).
Rutishauer, A. et al. Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic. Sci. Adv. 4, eaar4353 (2018).
Oswald, G. K., Rezvanbehbahani, S. & Stearns, L. A. Radar evidence of ponded subglacial water in Greenland. J. Glaciol. 64, 711–729 (2018).
Jordan, T. M. et al. A constraint upon the basal water distribution and thermal state of the Greenland Ice Sheet from radar bed echoes. Cryosphere 12, 2831–2854 (2018).
Dowdeswell, J. A. & Siegert, M. J. The physiography of modern Antarctic subglacial lakes. Glob. Planet. Change 35, 221–236 (2003).
Lauro, S. E. et al. Liquid water detection under the south polar layered deposits of Mars—a probabilistic inversion approach. Remote Sens. 11, 2445 (2019).
Hubbard, A., Lawson, W., Anderson, B., Hubbard, B. & Blatter, H. Evidence for subglacial ponding across Taylor Glacier, Dry Valleys, Antarctica. Ann. Glaciol. 39, 79–84 (2004).
Brass, G. W. Stability of brines on Mars. Icarus 42, 20–28 (1980).
Rennó, N. O. et al. Possible physical and thermodynamical evidence for liquid water at the Phoenix landing site. J. Geophys. Res. 114, E00E03 (2009).
Hecht, M. H. et al. Detection of perchlorate and soluble chemistry of Martian soil at the Phoenix Lander site. Science 325, 64–67 (2009).
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).
Hanley, J., Chevrier, V. F., Berget, D. J. & Adams, R. D. Chlorate salts and solutions on Mars. Geophys. Res. Lett. 39, L08201 (2012).
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).
Zorzano, M.-P., Mateo-Martí, E., Prieto-Ballesteros, O., Osuna, S. & Renno, N. Stability of liquid saline water on present day Mars. Geophys. Res. Lett. 36, L20201 (2009).
Gough, R. V., Chevrier, V. F. & Tolbert, M. A. Formation of aqueous solutions on Mars via deliquescence of chloride–perchlorate binary mixtures. Earth Planet. Sci. Lett. 393, 73–82 (2014).
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).
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).
Primm, K. M., Gough, R. V., Chevrier, V. F. & Tolbert, M. A. Freezing of perchlorate and chloride brines under Mars-relevant conditions. Geochim. Cosmochim. Acta 212, 211–220 (2017).
Primm, K. M., Stillman, D. E. & Michaels, T. I. Investigating the hysteretic behavior of Mars-relevant chlorides. Icarus 342, 113342 (2020).
Toner, J. D. & Catling, D. C. Chlorate brines on Mars: implications for the occurrence of liquid water and deliquescence. Earth Planet. Sci. Lett. 497, 161–168 (2018).
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).
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).
Toner, J. D., Catling, D. C. & Light, B. The formation of supercooled brines, viscous liquids, and low-temperature perchlorate glasses in aqueous solutions relevant to Mars. Icarus 233, 36–47 (2014).
Arnold, N. S., Conway, S. J., Butcher, F. E. & Balme, M. R. Modeled subglacial water flow routing supports localized intrusive heating as a possible cause of basal melting of Mars' south polar ice cap. J. Geophys. Res. 124, 2101–2116 (2019).
Willis, I. C., Pope, E. L., Gwendolyn, J. M., Arnold, N. S. & Long, S. Drainage networks, lakes and water fluxes beneath the Antarctic ice sheet. Ann. Glaciol. 57, 96–108 (2016).
Livingstone, S., Clark, C., Woodward, J. & Kingslake, J. Potential subglacial lake locations and meltwater drainage pathways beneath the Antarctic and Greenland ice sheets. Cryosphere 7, 1721–1740 (2013).
Maus, D. et al. Methanogenic archaea can produce methane in deliquescence-driven Mars analog environments. Sci. Rep. 10, 6 (2020).
Stamenković, V., Ward, L. M., Mischna, M. & Fischer, W. W. O2 solubility in Martian near-surface environments and implications for aerobic life. Nat. Geosci. 11, 905–909 (2018).
Cicchetti, A. et al. Observations of Phobos by the Mars Express radar MARSIS: description of the detection techniques and preliminary results. Adv. Space Res. 60, 2289–2302 (2017).
Schroeder, D. M., Blankenship, D. D. & Young, D. A. Evidence for a water system transition beneath Thwaites Glacier, West Antarctica. Proc. Natl Acad. Sci. USA 110, 12225–12228 (2013).
Li, J. et al. Density variations within the south polar layered deposits of Mars. J. Geophys. Res. 117, E04006 (2012).
Mouginot, J. et al. MARSIS surface reflectivity of the south residual cap of Mars. Icarus 201, 454–459 (2009).
Lauro, S. E. et al. Dielectric constant estimation of the uppermost Basal Unit layer in the Martian Boreales Scopuli region. Icarus 219, 458–467 (2012).
This work was supported by the Italian Space Agency (ASI) through contract ASI-INAF 2019–21-HH.0 and, in part, by EU H2020 agreement 776276 Planmap. MARSIS is operating onboard the European Space Agency spacecraft Mars Express. We would like to thank S. E. Beaubien for careful proofreading of the manuscript and improvement of the English.
The authors declare no competing interests.
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Lauro, S.E., Pettinelli, E., Caprarelli, G. et al. Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data. Nat Astron (2020). https://doi.org/10.1038/s41550-020-1200-6