NASA’s Perseverance rover has identified a potential biosignature within Jezero Crater’s ‘Bright Angel’ formation, based on analyses of the rock core nicknamed ‘Sapphire Canyon’ extracted from an outcrop called ‘Cheyava Falls’ in 2024. The peer-reviewed finding, published in Nature, outlines geochemical and mineralogical patterns that on Earth can be linked to past microbial activity, while emphasizing that non-biological processes remain possible explanations.
What the rover measured
Perseverance examined the ‘Bright Angel’ outcrops along the northern and southern margins of Neretva Vallis, an ancient, roughly 400-meter-wide river channel that once fed Jezero Crater. The site’s sedimentary rocks are composed of clay and silt and show enrichments associated with habitability.
- Fine-grained (clay- and silt-rich) sedimentary rocks that are favorable for preserving micro-scale textures and organics.
- Elevated organic carbon, sulfur, oxidized iron, and phosphorus within the unit.
- Millimeter-scale ‘leopard spot’ reaction fronts containing vivianite (hydrated iron phosphate) and greigite (iron sulfide), mapped at high resolution.
- Local geologic context that does not indicate sustained high temperatures or strongly acidic alteration, conditions that could create similar minerals abiotically.
These observations were captured primarily by the rover’s PIXL (X-ray lithochemistry) and SHERLOC (Raman and luminescence) instruments, which can resolve mineral chemistry and detect organics at fine scales.
Why it matters
On Earth, the co-occurrence of vivianite and greigite in sedimentary settings can reflect electron-transfer reactions that certain microbial metabolisms exploit. The Jezero signals therefore represent a plausible indirect fingerprint of past biological processes. However, abiotic pathways can also produce these minerals. The study’s interpretation weighs those alternatives against the measured geologic context, concluding that the signals are consistent with, but do not prove, past microbial activity.
Geologic and mission context
The potential biosignature appears in some of the youngest sedimentary rocks examined by Perseverance. This extends the time window during which surface water and habitable conditions may have persisted in Jezero. The rover has collected 27 rock cores since landing in February 2021, adding to a stratigraphically diverse archive for future analysis. Beyond its geology payload, Perseverance also operates a weather station and carries materials-exposure samples to inform future human missions.
Data integrity and assessment frameworks
The result advances along established life-detection frameworks, including NASA’s Confidence of Life Detection (CoLD) scale, which emphasizes multiple, independent lines of evidence, rigorous hypothesis testing, and reproducibility.
What to watch next
- Additional measurements across ‘Bright Angel’ exposures to test spatial consistency of the signals.
- Comparisons with other Jezero cores to assess whether similar mineral-organic patterns recur in different settings.
- Further application of the CoLD framework to evaluate the coherence and robustness of the evidence.
- Higher-fidelity laboratory analyses if and when samples become available for study on Earth.
These steps will help distinguish between biological and abiotic origins for the observed mineral and organic signatures at Jezero.
Source: NASA press release
