Azernews.Az

by Alimat Aliyeva

The Perseverance rover has detected the presence of complex organic molecules in two different shale deposits in the western part of Mars’ Jezero Crater — an area where, in 2025, the first potential organic “biosignatures” were already identified. This discovery strengthens the hypothesis that complex organic compounds may be widely preserved on Mars over geological timescales, AzerNEWS reports.

“Our analysis of hundreds of samples from two shale deposits at the bottom of an ancient river system confirmed the widespread presence of complex organic materials. We cannot determine whether they are of abiotic or biotic origin, but their occurrence even in exposed rock surfaces suggests that such molecules can persist on Mars for very long periods of time,” the researchers noted.

The findings were made by an international team of planetary scientists led by Kyle Akert from NASA’s Jet Propulsion Laboratory, based on data collected by Perseverance instruments in the western Jezero Crater, within the Neretva Vallis region. This area contains clay-rich and shale formations that formed at the bottom of an ancient Martian lake.

A year earlier, unusual shale deposits in this region were found to contain layers rich in phosphates and sulfides, along with complex organic compounds not previously detected on Mars. This prompted a more detailed investigation of adjacent rock layers and their chemical structure, using the rover’s SHERLOC spectrometer.

The measurements revealed the presence of complex organic compounds, including large carbon-based molecular structures, at hundreds of sampling points across these shale layers. Notably, these compounds were detected not only in well-protected mineral interiors but also in exposed rock surfaces that have likely been subjected to intense radiation and erosion for millions of years.

According to Akert and his colleagues, when combined with recent results from the Curiosity rover, these findings suggest that organic molecules may be widespread in at least two regions of Mars separated by more than 3,000 kilometers. This supports the idea that early Mars had environments capable of preserving potential traces of ancient life, if it ever existed.

Interestingly, on Earth, such organic molecules are often associated with biological processes. However, on Mars they can also form through non-biological chemistry, such as water-rock interactions or ultraviolet radiation-driven reactions. This leaves an open and important question: are these molecules chemical remnants of a once-habitable environment, or possible traces of ancient Martian biology?

The Perseverance rover, launched in 2020 and successfully landed in February 2021, continues to explore the ancient river delta in Jezero Crater. Beyond studying Martian geology, it is also collecting and caching rock samples in sealed containers for a future return mission to Earth under the Mars Sample Return (MSR) program.

One particularly intriguing aspect of this mission is that some of the collected samples may contain “time capsules” — microenvironments of ancient water or clay where organic molecules could have been shielded from harsh surface conditions for billions of years. If returned to Earth, these samples would allow scientists to analyze them with far greater precision than is possible with onboard instruments.