HR: 0830h
AN: P11B-1039    [PDF]
TI: Ground Ice on Earth and Mars
AU: * Martineau, N
EM: martineau@felix.geog.mcgill.ca
AF: McGill University, 805 Sherbrooke St. W., Montreal, Qc H3A 2K6 Canada
AU: Pollard, W
EM: pollard@felix.geog.mcgill.ca
AF: McGill University, 805 Sherbrooke St. W., Montreal, Qc H3A 2K6 Canada
AB: On Mars, just like on Earth, water exists in various phases and participates in a broad range of key processes. Even though present surface conditions on Mars, as defined by climate and atmospheric pressure, prevents the occurrence of liquid water on the surface, there is strong evidence suggesting that water was an important land-forming agent in the past (Carr 1996). This naturally raises the question, "where has the water gone?" Surficial water reservoirs that are directly observable on Mars include seasonal water ice deposits and permanent water ice deposits at the polar caps (Kieffer and Zent 1992, Clifford et al. 2000). Due to the existence of permafrost landform systems, such as polygonal ground, rootless cones, and frost mounts, it also has been speculated that much more water may be preserved as ground ice (Lucchitta 1981, Squyres and Carr 1986, Lanagan et al. 2001). Nevertheless, comparison of the likely patterns of ground ice on Mars with terrestrial equivalents has been limited. Fortunately, NASA's 2001 Odyssey data lends support to this hypothesis by identifying significant shallow ice-rich sediments by means of flux characteristics of neutrons, and gamma radiation, and spatial correlations to regions where it has been predicted that subsurface ice is stable (Bell 2002). The ice contents and stratigraphic distribution of the subsurface sediments on Mars, derived by the Odyssey Science Team, is not unlike the upper layers of terrestrial permafrost. Terrestrial polar environments, in particular the more stable permafrost and ground ice features like ice wedges and massive ground ice, may thus provide valuable clues in the search for water and ice on Mars. Of importance is the fact that these features of the earth's surface do not owe their origin to the seasonal freezing and thawing of the active layer. Under the cold, dry polar climates of the Arctic and Antarctic, periglacial and permafrost landforms have evolved, giving rise to distinctive landscapes directly related to the aggradation and degradation of ground ice. This paper examines ice stability as a function of climate and geomorphology, and offers suggestions for the exploration of Martian ground ice. It also describes the exploration strategies included in RIGID, a proposal for a capacitive-coupled instrumentation submitted to the Canadian Space Agency's Announcements of Opportunity during the summer of 2003. Bell, J., Tip of the Martian Iceberg? Science, 297, 60-61, 2002. Published online 30 May 2002, 10.1126/science.1074025. Carr, M., Water on Mars, Oxford University Press, New York., 229pp., 1996. Clifford S. M., A Model for the Hydrologic and Climatic Behavior of Water on Mars, J. Geophys. Res., 98, 10 973-11 016, 1993. Clifford et al., The state and future of Mars polar science and exploration, Icarus, 144, 210-242, 2000. Fanale, F.P., J.R. Salvail, A.P. Zentand, and S. E. Postawko, Global Distribution and Migration of Subsurface Ice on Mars, Icarus, 67, 1-18, 1986. Kieffer, H., and A. Zent, Quasi-periodic climate change on Mars, in Mars, edited by H.H. Kieffer et al., pp. 1135-1179, Univ. Arizona Press, Tucson, 1992. Lanagan, P.D., A.S. McEwen, L.P. Keszthelyi, and T. Thordarson, Rootless cones on Mars indicating the presence of shallow equatorial ground ice in recent times, GRL, 28, 2365-2368, 2001. Lucchitta, B., Mars and Earth: Comparison cold climate features. Icarus 45, 264-303, 1981. Squyres, S., and M. Carr, Geomorphic evidence for the distribution of ground ice on Mars, Science, 231, 249-252, 1986.
DE: 6020 Ice
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting