NASA’s Perseverance rover has detected complex organic carbon in two ancient mudstones within the Jezero crater, marking the most robust organic result from the site to date. According to a paper published in Spacedaily on June 24, 2026, the rover identified macromolecular carbon (MMC) in rocks located in the Bright Angel outcrop.
The Bright Angel formation is a light-toned outcrop along Neretva Vallis, an ancient river channel that transported water and sediment into the western delta of Jezero crater billions of years ago. The discovery, made using the rover’s SHERLOC instrument, means NASA rovers have now identified organic-bearing mudstones more than 2,000 miles apart on Mars, with previous discoveries made by the Curiosity rover in Gale crater.
The Nature of Macromolecular Carbon
Macromolecular carbon is a class of large, cross-linked carbon molecules that form a solid network of reduced carbon. This structure is highly durable, resisting heat and chemical breakdown, which allows it to survive in rock for extended periods. Scientists identified the MMC by detecting a pair of spectral features—the D-band and G-band near 1350 and 1600 wavenumbers.
The study, led by Ashley Murphy of the Planetary Science Institute and co-led by Kyle Uckert, deputy principal investigator for SHERLOC, reported hundreds of organic detections across the rocks. In one rock, the Cheyava Falls mudstone, MMC was found on the surface. In another, the carbon was bound to the primary silicate matrix that formed when the mudstone was originally laid down. Researchers state that finding the organic signal in both settings suggests organic chemistry was a recurring feature of ancient Jezero rather than a single delivery event.
Potential Biosignatures and Ambiguities
While MMC is tied to the chemistry of living things on Earth—such as coal and fossilized organic matter in microbial mats—it can also form through non-biological processes. According to Dr. Ashley Murphy, these include volcanic activity, reactions between rocks and water, or delivery via meteorites.
This latest finding adds to previous data regarding the Bright Angel outcrop. In a September 2025 Nature paper, Joel Hurowitz of Stony Brook University identified a potential biosignature
in the form of leopard-spot reaction fronts rich in iron sulfide (greigite) and iron phosphate (vivianite). These minerals may result from chemical reactions between organic matter and mud.
Despite these findings, officials emphasize that the data is not proof of life. Kyle Uckert stated that the presence of organic matter does not necessarily imply biology and that the study cannot claim biology played a role in the carbon described.
The Necessity of Sample Return
The Perseverance rover was not built to definitively determine if these organic molecules are biological or geological in origin.
Summary of Findings at Bright Angel Outcrop
| Feature | Discovery Detail | Potential Origin |
|---|---|---|
| Macromolecular Carbon | D-band and G-band spectral features | Biological (fossilized matter) or Geological (volcanism, meteorites, water) |
| Mineral Spots | Vivianite and Greigite | Microbial activity or non-biological chemical reactions |
| Location | Neretva Vallis / Jezero Crater | Ancient river channel and lake basin |
