Sedimentation Waves on the Martian North Polar Cap: Analogy with Megadunes in Antarctica

Wednesday, 17 December 2014
Clémence Herny1, Marion Masse1, Olivier Bourgeois1, Sabrina Carpy1, Stephane Le Mouelic1, Thomas Appéré2,3, Isaac B Smith4, Aymeric Spiga5, Laurent Perret6, Sebastien Rodriguez3, Thibaud Piquet6, Dominique Gaudin6 and Erwan Le Menn1, (1)LPGN Laboratoire de Planétologie et Géodynamique de Nantes, Nantes Cedex 03, France, (2)IPAG Institut de Planétologie et d’Astrophysique de Grenoble, Grenoble Cedex 9, France, (3)AIM - CEA/CNRS/Uni. P7, Gif/Yvette, France, (4)Southwest Research Institute Boulder, Boulder, CO, United States, (5)LMD Laboratoire de Météorologie Dynamique, Paris, France, (6)LHEEA Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique, Nantes, France
Complex feedbacks between katabatic winds and the cryosphere may lead to the development of sedimentation waves at the surface of ice sheets. These have been first described and named megadunes in Antarctica. Here we use topographic data, optical images, spectroscopic data and radar soundings, acquired by Mars orbiters, to show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. They have similarities with Antarctic megadunes regarding their surface morphology, texture, grain size, and internal stratigraphic architecture. Based on this analogy, we are currently developing a model of ice/wind interaction at the surface of ice sheets. In Antarctica the accumulation processes on megadunes fields is generally attributed to the wind-blown snow transport while on sedimentation waves of the North Polar Cap of Mars the accumulation seems to be dominated by sublimation/condensation processes at the surface. The model is designed to explore the implication of the water vapor mass transfer and heat transfer on the development of sedimentation waves both on Mars and Earth.