Stability of water ice under a porous nonvolatile layer: implications to the south polar layered deposits of Mars

The analysis of the Viking IRTM data led to the conclusion that the surface layer of the Mars south polar layered deposits has very low thermal inerti a. This is consistent with the layered deposits being mantled by a layer co nsisting of very hue dust. Analysis of the heat and mass transport through such a layer allows us to estimate the minimum thickness of a dust mantle r equired to guarantee water ice stability beneath it. We find that if the th ermal inertia is as low as 100 J m(-2) s(-1/2) K-1 and the dust layer is co mposed of particles of about 10 mum, then a 5 mm thick layer is sufficient to keep the ground water ice stable on at least seasonal time scales. (C) 2 001 Elsevier Science Ltd. All rights reserved.