Overview
- A University of Bern–led team identified scarp-fronted deposits that match terrestrial fan deltas, marking river mouths into a standing body of water.
- Delta-front elevations define the highest water level in Valles Marineris and imply an ocean filling the northern lowlands at least on the scale of Earth’s Arctic Ocean.
- The reconstruction integrates high-resolution color and stereo imagery from CaSSIS on ExoMars, ESA’s Mars Express, and NASA’s Mars Reconnaissance Orbiter.
- Though partly draped by wind-sculpted dunes, preserved fan geometries and sharp scarp fronts remain visible, allowing the shoreline to be mapped.
- Findings are published in npj Space Exploration, with orbital mineralogical studies now planned to test weathering, water–rock interactions, and duration of surface water.