Unprecedented mineral and organic compounds discovered in Mars’ Jezero Crater

The Perseverance rover has uncovered sedimentary rocks containing minerals and organic matter organized into structures never before seen on Mars, opening up new perspectives on the Red Planet’s past habitability.

Research teams involving several CNRS Terre & Univers laboratories used NASA’s Perseverance rover to analyze intriguing spotted rocks found in the sediments of a valley in Jezero Crater, in the geological formation known as “Bright Angel.” This study reveals previously unknown mineral and organic associations.

Detailed analysis of these sedimentary rocks revealed the presence of organic matter—i.e., carbon-based molecules—closely associated with phosphate and iron sulfide minerals, concentrated in the form of submillimeter nodules and millimeter-scale reaction fronts. The researchers identified these minerals as probably vivianite (ferrous iron phosphate) and greigite (iron sulfide), mineral phases that, on Earth, typically form during redox reactions involving organic matter in low-temperature aqueous environments.

This discovery is particularly significant because the formation of these minerals requires water to mobilize and concentrate the elements observed. The geological context and petrography indicate that these reactions occurred at low temperatures in a lacustrine sedimentary environment, conditions compatible with habitability. On Earth, the formation of such mineral associations is frequently linked to biological processes, particularly the microbial reduction of iron and sulfates. However, the researchers point out that a purely geological origin remains possible. Abiotic formation scenarios (i.e., involving only physicochemical processes), involving the oxidation of organic matter coupled with the reductive dissolution of iron oxides, are also consistent with the observations. The characteristics of these rocks therefore constitute a “potential biosignature” that requires further analysis to determine their origin with certainty.

A sample of these remarkable rocks, named “Sapphire Canyon,” was collected by Perseverance for future return to Earth. Only a variety of laboratory analyses, which are much more sensitive and spatially resolved than those possible in situ on Mars, will allow us to better determine the biological or abiotic origin of this rock’s characteristics.

CNRS Laboratories involved

• Institut de Recherche en Astrophysique et Planétologie (IRAP – OMP) 
  Tutelles : CNRS / CNES / Université de Toulouse
• Laboratoire de Géologie de Lyon : Terre, Planètes, Environnement (LGL-TPE – OSUL) 
  Tutelles : CNRS / ENS Lyon / Univ. Claude Bernard / UJM Saint-Étienne
• Institut de Planétologie et d’Astrophysique de Grenoble (IPAG – OSUG) 
  Tutelles : CNRS / UGA
• Laboratoire Géosciences Environnement Toulouse (GET – OMP) 
  Tutelles : CNRS / CNES / IRD / Université de Toulouse
• Laboratoire de Planétologie et Géosciences (LPG – OSUNA) 
  Tutelles : CNRS / Nantes Université / Université d’Angers / Le Mans Université
• Laboratoire d’Instrumentation et de Recherche en Astrophysique (LIRA – Obs. Paris) 
  Tutelles : CNRS / Observatoire de Paris – PSL / Sorbonne Université / Université Paris Cité
• Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC – Ecce Terra) 
  Tutelles : CNRS / Sorbonne Université / MNHN / IRD

Further Resource

• Scientific paper : Hurowitz, J.A. et al. Redox-driven mineral and organic associations in Jezero Crater, Mars. Nature (2025). https://doi.org/10.1038/s41586-025-09413-0

IRAP Contact

• Agnès Cousin, agnes.cousin@irap.omp.eu