Mars Study Maps 600-km Oxia Clays, Suggesting 4-Billion-Year-Old Ocean
Updated
Updated · European Space Agency · Jun 4
Mars Study Maps 600-km Oxia Clays, Suggesting 4-Billion-Year-Old Ocean
3 articles · Updated · European Space Agency · Jun 4
Summary
A new Icarus study found clay deposits at Oxia Planum stretch about 600 km to Mawrth Vallis and rise more than 1 km, far beyond earlier estimates.
Orbiter data from ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter showed matching clay layers at both sites, pointing to a regional—possibly global—water-driven process on early Mars.
Researchers say one leading scenario is a several-kilometre-deep ocean around 4 billion years ago; another is widespread flooding from ancient groundwater reservoirs.
The analysis also identified an ancient cratered paleosurface marking a pause in sedimentation, followed by a shift in water chemistry that fits an intermittently wet early Martian climate.
Those findings sharpen the case for ExoMars’ Rosalind Franklin rover, which will land at Oxia Planum and use a 2-metre drill and onboard lab to test the orbital results and search for biosignatures.
A lost Martian ocean or colossal groundwater floods? Which story of Mars's past will the new rover uncover?
With NASA's sample return mission stalled, is Europe's rover our only hope to find definitive proof of Martian life?
Mars’ 4-Billion-Year-Old Ocean at Oxia Planum: Geological Evidence and the Next Frontier in Life Detection
Overview
Recent discoveries have transformed our understanding of Mars by revealing that the Oxia Planum region once hosted a vast, ancient ocean, possibly as far back as four billion years ago. Scientists identified this area as a water-rich environment after constructing a new global map of Mars minerals, which showed extensive clay-rich deposits. These clays, formed only in the presence of water, provide crucial evidence of Mars’s wet past and make Oxia Planum a prime location to search for signs of ancient life. This breakthrough guides future exploration and deepens our knowledge of Mars’s habitability.