Permanently shadowed regions near the poles of Mercury and the Moon may cold-trap water ice for geologic time periods. In past studies, thick ice deposits have been detected on Mercury, but not on the Moon, despite their similar thermal environments. Here we report evidence for thick ice deposits inside permanently shadowed simple craters on both Mercury and the Moon. We measure the depth/diameter ratio of approximately 2,000 simple craters near the north pole of Mercury using Mercury Laser Altimeter data. We find that these craters become distinctly shallower at higher latitudes, where ice is known to have accumulated on their floors. This shallowing corresponds to a maximum infill of around 50 m, consistent with previous estimates. A parallel investigation of approximately 12,000 lunar craters using Lunar Reconnaissance Orbiter data reveals a similar morphological trend near the south pole of the Moon, which we conclude is also due to the presence of thick ice deposits. We find that previously detected surface ice deposits in the south polar region of the Moon are spatially correlated with shallow craters, indicating that the surface ice may be exhumed or linked to the subsurface via diffusion. The family of lunar craters that we identify are promising targets for future missions, and may also help resolve the apparent discrepancy between the abundance of frozen volatiles on Mercury and the Moon.
Subscribe to Journal
Get full journal access for 1 year
only $14.08 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The code used to model the temperature of permanently shadowed craters20 can be accessed through a GitHub repository with the identifier https://doi.org/10.5281/zenodo.3238628. It may also be downloaded from: https://github.com/liorruba/shallow_simple_craters.git.
Urey, H. C. The Planets, Their Origin and Development (Yale Univ. Press, 1952).
Watson, K., Murray, B. & Brown, H. On the possible presence of ice on the Moon. J. Geophys. Res. 66, 1598–1600 (1961).
Harmon, J. K. & Slade, M. A. Radar mapping of mercury: full-disk images and polar anomalies. Science 258, 640–643 (1992).
Slade, M. A., Butler, B. J. & Muhleman, D. O. Mercury radar imaging: evidence for polar ice. Science 258, 635–640 (1992).
Paige, D. A. et al. Thermal stability of volatiles in the north polar region of Mercury. Science 339, 300–303 (2013).
Deutsch, A. N., Head, J. W., Chabot, N. L. & Neumann, G. A. Constraining the thickness of polar ice deposits on Mercury using the Mercury Laser Altimeter and small craters in permanently shadowed regions. Icarus 305, 139–148 (2018).
Stacy, N. J. S., Ford, P. G. & Campbell, D. B. Arecibo radar mapping of the lunar poles: a search for ice deposits. Science 276, 1527–1530 (1997).
Campbell, D. B., Campbell, B. A., Carter, L. M., Margot, J.-L. & Stacy, N. J. S. No evidence for thick deposits of ice at the lunar south pole. Nature 443, 835–837 (2006).
Colaprete, A. et al. Detection of water in the LCROSS ejecta plume. Science 330, 463–468 (2010).
Hayne, P. O. et al. Evidence for exposed water ice in the Moon’s south polar regions from Lunar Reconnaissance Orbiter ultraviolet albedo and temperature measurements. Icarus 255, 58–69 (2015).
Fisher, E. A. et al. Evidence for surface water ice in the lunar polar regions using reflectance measurements from the Lunar Orbiter Laser Altimeter and temperature measurements from the Diviner Lunar Radiometer Experiment. Icarus 292, 74–85 (2017).
Li, S. et al. Direct evidence of surface exposed water ice in the lunar polar regions. Proc. Natl Acad. Sci. USA 115, 8907–8912 (2018).
Paige, D. A. et al. Diviner Lunar Radiometer observations of cold traps in the Moon’s south polar region. Science 330, 479–482 (2010).
Lawrence, D. J. A tale of two poles: Toward understanding the presence, distribution, and origin of volatiles at the polar regions of the Moon and Mercury. J. Geophys. Res. Planets 122, 21–52 (2017).
Mitrofanov, I. G. et al. Hydrogen mapping of the lunar south pole using the LRO neutron detector experiment LEND. Science 330, 483–486 (2010).
Feldman, W. C. et al. Fluxes of fast and epithermal neutrons from Lunar Prospector: evidence for water ice at the lunar poles. Science 281, 1496–1500 (1998).
Lawrence, D. J. et al. Evidence for water ice near Mercury’s north pole from MESSENGER Neutron Spectrometer measurements. Science 339, 292–296 (2013).
Hawkins, S. E. et al. The Mercury dual imaging system on the MESSENGER spacecraft. Space Sci. Rev. 131, 247–338 (2007).
Cavanaugh, J. F. et al. The Mercury Laser Altimeter Instrument for the MESSENGER Mission. Space Sci. Rev. 131, 451–479 (2007).
Ingersoll, A. P., Svitek, T. & Murray, B. C. Stability of polar frosts in spherical bowl-shaped craters on the Moon, Mercury, and Mars. Icarus 100, 40–47 (1992).
Rubanenko, L., Mazarico, E., Neumann, G. A. & Paige, D. A. Ice in Micro Cold Traps on Mercury: Implications for Age and Origin. J. Geophys. Res. Planets 123, 2178–2191 (2018).
Moses, J. I., Rawlins, K., Zahnle, K. & Dones, L. External sources of water for Mercury’s putative ice deposits. Icarus 137, 197–221 (1999).
Chabot, N. L. et al. Images of surface volatiles in Mercury’s polar craters acquired by the MESSENGER spacecraft. Geology 42, 1051–1054 (2014).
Paige, D. A., Wood, S. E. & Vasavada, A. R. The thermal stability of water ice at the poles of mercury. Science 258, 643–646 (1992).
Salamunićcar, G., Lončarić, S., Grumpe, A. & Wöhler, C. Hybrid method for crater detection based on topography reconstruction from optical images and the new LU78287GT catalogue of Lunar impact craters. Adv. Space Res. 53, 1783–1797 (2014).
Rubanenko, L. & Aharonson, O. Stability of ice on the Moon with rough topography. Icarus 296, 99–109 (2017).
Kokhanov, A. A., Kreslavsky, M. A. & Karachevtseva, I. P. Small impact craters in the polar regions of the Moon: peculiarities of morphometric characteristics. Sol. Syst. Res. 49, 295–302 (2015).
Schorghofer, N. & Taylor, G. J. Subsurface migration of H2O at lunar cold traps. J. Geophys. Res. Planets 112, E02010 (2007).
Schorghofer, N. & Aharonson, O. The lunar thermal ice pump. Astrophys. J. 788, 169 (2014).
Schorghofer, N. Two-dimensional description of surface-bounded exospheres with application to the migration of water molecules on the Moon. Phys. Rev. E 91, 052154 (2015).
Fa, W. & Wieczorek, M. A. Regolith thickness over the lunar nearside: results from Earth-based 70-cm Arecibo radar observations. Icarus 218, 771–787 (2012).
Spudis, P. D. et al. Evidence for water ice on the Moon: results for anomalous polar craters from the LRO Mini-RF imaging radar. J. Geophys. Res. Planets 118, 2016–2029 (2013).
Haruyama, J. et al. Long-lived volcanism on the lunar farside revealed by SELENE terrain camera. Science 323, 905–908 (2009).
McEwen, A. S. et al. Galileo observations of post-Imbrium lunar craters during the first Earth–Moon flyby. J. Geophys. Res. Planets 98, 17207–17231 (1993).
Pike, R. J. in Impact and Explosion Cratering (eds Roddy, D. J. et al.) 489–509 (Pergamon, 1977).
Neumann, G. A. MESSENGER E/V/H MLA 4 GDR DATA V1.0 (NASA Planetary Data System, 2013).
Neumann, G. A. Lunar Orbiter Laser Altimeter Raw Data Set LRO-L-LOLA-4-GDR-V1.0 (NASA Planetary Data System, 2010).
Bierhaus, E. B. et al. Secondary craters and ejecta across the solar system: populations and effects on impact-crater-based chronologies. Meteorit. Planet. Sci. 53, 638–671 (2018).
Schultz, P. H. & Singer, J. A comparison of secondary craters on the Moon, Mercury, and Mars. In Proceedings Lunar and Planetary Science Conference 11th 2243–2259 (Pergamon, 1980).
Pike, R. J. Apparent depth/apparent diameter relation for lunar craters. In Proceedings Lunar and Planetary Science Conference 8th 3427–3436. (Pergamon, 1977).
Buhl, D., Welch, W. J. & Rea, D. G. Reradiation and thermal emission from illuminated craters on the lunar surface. J. Geophys. Res. 73, 5281–5295 (1968).
Domingue, D. L., Murchie, S. L., Chabot, N. L., Denevi, B. W. & Vilas, F. Mercury’s spectrophotometric properties: update from the Mercury Dual Imaging System observations during the third MESSENGER flyby. Planet. Space Sci. 59, 1853–1872 (2011).
This work was supported in part by the Lunar Reconnaissance Orbiter Diviner (award no. NNG09EK06C) and MESSENGER (grant no. NNX07AR64G) missions. We are grateful to J.-P. Williams for helpful discussions and suggestions and S. Li for providing us with his previously published surface ice data. L.R. thanks T. Powell for many helpful discussions. The authors would also like to express their gratitude to the LOLA and MLA teams for acquiring high-precision laser altimeter datasets of the Moon and Mercury. LRO and MLA data were obtained from the Planetary Data System.
The authors declare no competing interests.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Rubanenko, L., Venkatraman, J. & Paige, D.A. Thick ice deposits in shallow simple craters on the Moon and Mercury. Nat. Geosci. 12, 597–601 (2019). https://doi.org/10.1038/s41561-019-0405-8
Analyzing the ages of south polar craters on the Moon: Implications for the sources and evolution of surface water ice.
Assessing the Roughness Properties of Circumpolar Lunar Craters: Implications for the Timing of Water‐Ice Delivery to the Moon
Geophysical Research Letters (2020)
Journal of Geophysical Research: Planets (2020)
Laboratory investigations of Lunar ice imaging in permanently shadowed regions using reflected starlight
Acta Astronautica (2020)