Bright Angel formation Yields Complex Organics

The Bright Angel formation has yielded evidence of organic matter. It's a geological region within an ancient Martian river valley. And this discovery comes from an international team of about sixty researchers tracing the history of Jezero Crater, a forty-five kilometer wide basin that once contained a lake fed by two distinct river systems. So the rover Perseverance, which has been exploring this crater since February 2021, used its specialized Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals instrument to analyze the rocks. It's a big find.

Laser light reveals organic chemistry

They targeted a rock feature nicknamed Cheyava Falls. To identify these compounds, the instrument zapped the rock surface with a laser light, using Raman spectroscopy to analyze the light bouncing back and determine the specific molecular structures present in the sample. But this investigation followed the July 2024 detection of distinctive leopard spots on Cheyava Falls, which had already drawn intense interest from the science team. It's quite a story.

The analysis confirmed that the rocks in the Bright Angel formation contain organics alongside several secondary minerals. These secondary minerals, which arrived after the organic compounds had already formed, include:

• Carbonates, such as chalk or limestone
• Sulfates, such as plaster or Epsom salts
• Macromolecular carbon, which forms a complex three-dimensional network of carbon atoms

It's unclear if this macromolecular carbon came from ancient life or simple chemical reactions. But the molecules' location stunned the team. They were found shockingly close to the surface, separated from the open Martian atmosphere by a distance less than the width of a single piece of paper.

The protective role of Martian mudstones

This close proximity to the surface poses a major scientific puzzle. Mars lacks a magnetic field and an ozone layer, leaving its surface completely exposed to harsh solar and cosmic radiation that would quickly destroy any organic matter. Radiation and chemical oxidants typically destroy organic matter quickly. On Earth, fine-grained mudstones act as a natural shield, preserving organic material from environmental degradation over billions of years, and researchers have focused on Martian mudstones for this exact reason, hoping the compact sediment could protect ancient biological signatures from space radiation.

The Martian surface environment includes radiation and chemical oxidants that are destructive to organics, and terrestrial laboratory simulations have shown that the survival time of organics in Martian-like conditions, especially at or near the surface, depends on factors such as the type of organic molecule and the surrounding minerals. The MMC detected in the Bright Angel mudstones is either resistant to degradation and/or has been sufficiently shielded by other minerals, such as clays, or iron-rich Martian soil, said Dr. Ashley Murphy.

, Dr. Ashley Murphy, Postdoctoral Research Scientist at the Planetary Science Institute

Comparing Jezero and Gale craters

Perseverance scanned the Bright Angel formation. But another active explorer was finding similar clues thousands of miles away, and NASA's Curiosity rover identified more than twenty organic molecules from clay sandstones in Gale Crater, a site located about 3,800 kilometers from its sibling. Gale Crater is much larger than Jezero. It's a massive basin spanning 154 kilometers in diameter. And it features a giant central mountain known as Mount Sharp.

A study published in April 2026 detailed these findings from Curiosity. But it reinforced the idea that wet environments were common on ancient Mars. While Jezero Crater is characterized by its massive river delta where inflow slowed and deposited sediments under freshwater conditions, Gale Crater also hosted a long-lived lake billions of years ago. So the presence of organic molecules in both locations provides critical data as scientists try to reconstruct the habitability of the Martian past. They're key clues. We've got a lot to learn.