Estimate of aeolian dust thickness in Arabia Terra, Mars: Implications of a thick mantle (> 20 m) for hydrogen detection

N. Mangold (1, 2) , V. Ansan (1, 3) , Ph. Masson (1) , C. Vincendon (1, 4)

1 IDES - Interactions et dynamique des environnements de surface
2 LPGN - Laboratoire de Planétologie et Géodynamique de Nantes [UMR 6112]
3 UN - Université de Nantes
4 IAS - Institut d'astrophysique spatiale

This study describes a method for estimating dust thickness on the surface of Mars using the distribution of small impact craters (<1 km in diameter), obtained from high resolution Mars Orbiter Camera (MOC) images on the Mars Global Surveyor (MGS) space probe. The distribution of actual impact craters is different from the theoretical distribution of meteoritic impact flux due to the progressive burying of impact craters by dust deposits. The rim height for the largest buried impact crater was found to provide an approximate minimum thickness for dust blanketing the surface. This method was applied to the region of Arabia Terra, found to be covered by a dust mantle with a minimum thickness of 20 meters. The presented results indicate that Arabia Terra was a regional sink for dust during most of the Amazonian epoch (>3 Ga). Results also suggest that hydrogen, detected by the Neutron Spectrometer within this region in the top meter, is present in the dust and not in the underlying bedrock.

Domaines: Sciences de la Terre

N. Mangold, V. Ansan, Ph. Masson, C. Vincendon. Estimate of aeolian dust thickness in Arabia Terra, Mars: Implications of a thick mantle (> 20 m) for hydrogen detection. Géomorphologie : relief, processus, environnement, 2009, 15 (1), pp.23-31. ⟨10.4000/geomorphologie.7472⟩. ⟨hal-00380453⟩