Evidence of liquid water in recent debris avalanche on Mars

Abstract

The identification of landforms associated to liquid water on Mars is a major goal for the understanding of the geologic and climatic evolution of this planet. In the region of Reull Vallis, near Hellas basin, lobate debris aprons are recent landforms due to the creep of water ice mixed with rocks. Among these landforms, one unusually long debris apron has a tongue‐shape and gross morphology that indicates a different mechanism of deposition. This study demonstrates, using topographic data from Viking DEM and MOLA (Mars Observer Laser Altimeter) that the geometric parameters of this feature support the presence of liquid water during its flow. This landform is therefore comparable in size to the most developed wet debris avalanches on Earth. Its late Amazonian age questions the presence of near‐surface liquid water in the recent geological past of Mars.