Summary
New research mapping Oxia Planum — the confirmed landing site for esa’s rosalind-franklin-rover — reveals clay deposits extending roughly 600 km across and rising over 1 km in altitude, far beyond prior estimates. Scientists used data from NASA’s Mars Reconnaissance Orbiter and ESA’s Mars Express to map these formations, which formed approximately 4 billion years ago and predate clays at neighboring Mawrth Vallis. Researchers identified a paleosurface — a heavily cratered ancient boundary layer — marking a pause in sedimentation and a shift in water chemistry between two main clay-bearing units, interpreted as evidence for an intermittently wet early Martian climate. The scale of the deposits is consistent with either a deep ancient ocean or extensive groundwater flooding. When the rosalind-franklin-rover arrives, its 2-meter drill, spectrometers, cameras, ground-penetrating radar, and the Mars Organic Molecule Analyzer (MOMA) will probe these clays for biosignatures and environmental records of early Mars.
Key Claims
- Oxia Planum’s clay deposits extend ~600 km across and >1 km in altitude — significantly larger than previously estimated.
- The clays formed ~4 billion years ago, making them older than those at Mawrth Vallis (a competing landing-site candidate).
- A paleosurface (heavily cratered ancient surface) separates two clay-bearing units and marks a shift in water chemistry and mineralogy.
- Two competing hypotheses explain the deposits: a deep ocean reaching several km, or extensive groundwater flooding of vast plains.
- The rosalind-franklin-rover will drill to 2 m depth, targeting samples shielded from cosmic-ray destruction and analyzing them for biosignatures.
- Lead researcher Inés Torres Auré: “We now have a new timeline: Oxia Planum’s clays formed first, about 4 billion years ago, predating those at Mawrth Vallis.”
Notable Quotes
“We now have a new timeline: Oxia Planum’s clays formed first, about 4 billion years ago, predating those at Mawrth Vallis.” — Inés Torres Auré (lead researcher)