Climbing and falling dunes in valles marineris, mars

Multiple occurrences of "wall dunes" are found several kilometers above the Valles Marineris canyon floor. Dune slip face orientation and bed form morphologies indicate transport direction and whether the wall dunes are climbing dunes or falling dunes. On Earth, these types of dunes form in a unidirectional wind regime and are strongly controlled by the local topography. Newly acquired Mars Reconnaissance Orbiter (MRO) images and topography of the walls of Valles Marineris show similar sand dune morphologies, as wind blown sediment has interacted with local and regional topography. Primarily found in Melas and Coprates Chasmata, these climbing and falling dunes are relevant for understanding aeolian sediment flux, sediment sources, and wind directions. Falling dunes show photogeologic and thermophysical evidence of their sand being provided by adjacent outcrops.