GEOMORPHIC STUDY OF DEBRIS FLOWS ON THE RUSSELL DUNE (MARS) : COMPARISON OF DEBRIS FLOWS AND PRESENT FLOWS ACTIVITY
Résumé
Introduction : Liquid water is not likely to be found on the surface of Mars because of atmospheric pres-sure/temperature conditions below water's triple-point. However, the discovery of gullies suggests that significant amounts of liquid water has flowed on Mars in a recent past [1]. This study focus on morphology of gullies over dunes on the Russell crater (54.5°S ; 12.7°E). Recent numerical simulations have shown that sinuous shapes of these Martian gullies over dunes can be better reproduced with liquid-water-bearing flows [2]. The discovery of debris flows on sand dunes is unexpexted and the origin of the fluid necessary for the formation of debris flows remains currently a mystery. Recent work shows that the gullies located on the Russell dune are not only extremely youthfull but seem also to be still active [3]. This study aims to : 1/ realize a morphological description of the debris flows of the Russell dune and the Present flow activity using the HiRISE images ; 2/ estimates the physical properties of the flows (velocities, flow rates) and the maximum grain size of the dune surface material ; 3/ use the different flow morphologies and the calculated parameters to compare the debris flows and the Present flow activity.
Origine | Fichiers produits par l'(les) auteur(s) |
---|