Encyclopedia of Planetary Landforms

2015 Edition
| Editors: Henrik Hargitai, Ákos Kereszturi

Softened Crater

  • Michelle R. KoutnikEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-3134-3_357


An impact crater displaying muted topography in a volatile-rich target material.


Terrain softened crater (antonym: unsoftened crater)


Structure of impact craters depends on the target material (e.g., Strom et al. 1992; Barlow and Perez 2003; Stewart and Valiant 2006) and can exhibit distinct structures if the target is rich in volatiles (e.g., Senft and Stewart 2008). An impact into a target substrate that is volatile-rich or contains buried volatiles can result in a crater with a “softened” form compared to an impact into a substrate with no volatiles. Using imagery, Jankowski and Squyres ( 1992) assessed craters in the mid-latitudes of Mars for crater depth, convexity or concavity of crater wall, rounding of the crater rim, and rim height. They found that softened simple and complex craters had rounded rims and more convex crater-wall slopes; and otherwise sharp features were rounded (Figs. 1 and 2). Softened craters are shallower than unsoftened...
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  1. Bandfield J (2007) High-resolution subsurface water-ice distributions on Mars. Nature 447:64–68CrossRefGoogle Scholar
  2. Banks ME, Byrne S, Galla K, McEwen AS, Bray VJ, Dundas CM, Fishbaugh KE, Herkenhoff KE, Murray BC (2010) Crater population and resurfacing of the Martian north polar layered deposits. J Geophys Res 115, E08006. doi:10.1029/2009JE003523Google Scholar
  3. Barata T, Alves EI, Machado A, Barberes GA (2012) Characterization of palimpsest craters on Mars. Planet Space Sci 72:62–69CrossRefGoogle Scholar
  4. Barlow, NG, Perez CB (2003) Martian impact crater ejecta morphologies as indicators of the distribution of subsurface volatiles. J Geophys Res 108. doi: 10.1029/2002JE002036Google Scholar
  5. Basilevsky AT, Keller HU (2007) Craters, smooth terrains, flows, and layering on the comet nuclei. Solar Syst Res 41(2):109–117CrossRefGoogle Scholar
  6. Boynton W, Feldman W, Squyres S, Prettyman T (2002) Distribution of hydrogen in the near surface of Mars: evidence for subsurface ice deposits. Science 297:81–85CrossRefGoogle Scholar
  7. Clifford S (1993) A model for the hydrologic and climatic behavior of water on Mars. J Geophys Res 98:10973–11016CrossRefGoogle Scholar
  8. Colaprete A, Jakosky B (1998) Ice flow and rock glaciers on Mars. J Geophys Res 103:5897–5909CrossRefGoogle Scholar
  9. Dombard AJ, McKinnon WB (2006) Elastoviscoplastic relaxation of impact crater topography with application to Ganymede and Callisto. J Geophys Res 111:E01001. doi:10.1029/2005JE002445Google Scholar
  10. Hall JL, Solomon SC, Head JW (1981) Lunar floor-fractured craters: evidence for viscous relaxation of crater topography. J Geophys Res 86:9537–9552CrossRefGoogle Scholar
  11. Hartmann WK (1966) Early lunar cratering. Icarus 5:406–418CrossRefGoogle Scholar
  12. Hartmann WK, Esquerdo G (1999) “Pathological” Martian craters: evidence for a transient obliteration event? Meteorit Planet Sci 34:159–165CrossRefGoogle Scholar
  13. Holt JW et al (2008) Radar sounding evidence for buried glaciers in the southern mid-latitudes of Mars. Science 322:1235–1238CrossRefGoogle Scholar
  14. Jankowski DJ, Squyres SW (1992) The topography of impact craters in “softened” terrain on Mars. Icarus 100:26–39CrossRefGoogle Scholar
  15. Kirchoff MR, Schenk P (2009) Crater modification and geologic activity in Enceladus’ heavily cratered plains: evidence from the impact crater distribution. Icarus 202:656–668CrossRefGoogle Scholar
  16. Koutnik M, Byrne S, Murray B (2002) South polar layered deposits of Mars: the cratering record. J Geophys Res 107:10-1–10-10. doi:10.1029/2001JE001805Google Scholar
  17. Kreslavsky M, Head J (2003) North–south topographic slope asymmetry on Mars: evidence for insolation-related erosion at high obliquity. Geophys Res Lett 30:1815. doi:10.1029/2003GL017795CrossRefGoogle Scholar
  18. Kreslavsky M, Head J, Marchant D (2008) Periods of active permafrost layer formation during the geological history of Mars: implications for circum-polar and mid-latitude surface processes. Planet Space Sci 56:289–302CrossRefGoogle Scholar
  19. Li H, Robinson M, Jurdy D (2005) Origin of Martian northern hemisphere mid-latitude lobate debris aprons. Icarus 176:382–394CrossRefGoogle Scholar
  20. Mangold N, Allemand P (2001) Topographic analysis of features related to ice on Mars. Geophys Res Lett 28:407–410CrossRefGoogle Scholar
  21. Masursky H (1964) A preliminary report on the role of isostatic rebound in the geologic development of the lunar crater Ptolemaeus. Astrogeologic studies, annual progress report A. U.S. Geological Survey, Washington, DC, pp 102–134Google Scholar
  22. Milliken R, Mustard J, Goldsby D (2003) Viscous flow features on the surface of Mars: observations from high-resolution Mars Orbiter Camera (MOC) images. J Geophys Res 108. doi:10.1029/2002JE002005Google Scholar
  23. Mouginis-Mark PJ (1979) Martian fluidized crater morphology: variations with crater size, latitude, altitude, and target material. J Geophys Res 84:8011–8022CrossRefGoogle Scholar
  24. Parmentier EM, Head JW (1981) Viscous relaxation of impact craters on icy planetary surfaces: determination of viscosity variation with depth. Icarus 47:100–111CrossRefGoogle Scholar
  25. Parsons RA, Nimmo F (2009) North–south asymmetry in Martian crater slopes. J Geophys Res 114. doi:10.1029/2007JE003006Google Scholar
  26. Pathare AV, Paige DA, Turtle E (2005) Viscous relaxation of craters within the Martian south polar layered deposits. Icarus 174(2):396–418CrossRefGoogle Scholar
  27. Perron JT, Dietrich WE, Howard AD, McKean JA, Pettinga JR (2003) Ice-driven creep on Martian debris slopes. Geophys Res Lett 30. doi:10.1029/2003/GL017603Google Scholar
  28. Plaut J et al (2007) Subsurface radar sounding of the south polar layered deposits of Mars. Science 316:92–95CrossRefGoogle Scholar
  29. Robuchon G, Nimmo F, Roberts J, Kirchoff M (2011) Impact basin relaxation at Iapetus. Icarus 214:82–90CrossRefGoogle Scholar
  30. Schaller EL, Murray B, Pathare AV, Rasmussen J, Byrne S (2005) Modification of secondary craters on the Martian South Polar Layered Deposits. J Geophys Res 110. doi:10.1029/2004JE002334Google Scholar
  31. Senft LE, Stewart ST (2008) Impact crater formation in icy layered terrains on Mars. Meteorit Planet Sci 43(12):1993–2013CrossRefGoogle Scholar
  32. Soderblom LA, Kreidler TJ, Masursky H (1973) Latitudinal distribution of a debris mantle on the Martian surface. J Geophys Res 78(20):4117–4122CrossRefGoogle Scholar
  33. Squyres S (1989) Urey prize lecture: water on Mars. Icarus 79:229–288CrossRefGoogle Scholar
  34. Squyres S, Carr M (1986) Geomorphic evidence for the distribution of ground ice on Mars. Science 231:249–252CrossRefGoogle Scholar
  35. Stewart ST, Valiant GJ (2006) Martian subsurface properties and crater formation processes inferred from fresh impact crater geometries. Meteorit Planet Sci 41:1509–1537CrossRefGoogle Scholar
  36. Strom RG, Croft SK, Barlow NG (1992) The Martian impact cratering record. In Mars: Kieffer HH, Jakosky BM, Snyder CW, Matthews MS (eds). The University of Arizona Press, Tucson, AZ, pp 383–423Google Scholar
  37. Thomas PJ, Schubert G (1988) Power law rheology of ice and the relaxation style and retention of craters on Ganymede. J Geophys Res 93:13755–13762CrossRefGoogle Scholar
  38. Willmes M, Reiss D, Hiesinger H, Zanetti M (2012) Surface age of the ice–dust mantle deposit in Malea Planum, Mars. Planet Space Sci 60:199–206CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Department of Earth and Space SciencesUniversity of WashingtonSeattleUSA