Dynamics of unusual debris flows on Martian sand dunes

Abstract

Gullies that dissect sand dunes in Russell impact crater often display debris flow-like deposits in their distal reaches. The possible range of both the rheological properties and the flow rates are estimated using a numerical simulation code of a Bingham plastic flow to help explain the formation of these features. Our simulated results are best explained by a rapid debris flow. For example, a debris flow with the viscosity of 10 2 Pa s and the yield strength of 10 2 Pa can form the observed deposits with a flow rate of 0.5 m 3 /s sustained over several minutes and total discharged water volume on the order of hundreds of cubic meters, which may be produced by melting a surface layer of interstitial ice within the dune deposits to several centimeters depth. I NDEX T ERMS : 1824 Hydrology: Geomorphology (1625); 1823 Hydrology: Frozen ground; 1625 Global Change: Geomorphology and weathering (1824, 1886); 6207 Planetology: Solar System Objects: Comparative planetology; 6225 Planetology: Solar System Objects: Mars.