Exciting Martian Mudstone Has Features That Might Be Considered Biosignatures

An international team of researchers reports new insights into observations from NASA’s Perseverance rover. Last year, the rover sampled mudstone with peculiar mineral formations. New analysis provides further peculiarities in the sample, making the case for possible biosignatures.

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Let’s stress right now that nobody is claiming aliens. We are nowhere close to being able to confirm what exactly made these minerals. That’s the exciting bit! The team cannot dismiss the possibility that we are looking at a biosignature.

The analysis focused on the Bright Angel formation, which included more insight into the now famous "Cheyava Falls" rock, as well as an analysis of a rock now called “Apollo Temple”. The rover also collected a core sample called “Sapphire Canyon”.

The team has identified iron phosphate and iron sulfide, organized in nodules and specks across the rocks. There are also features that are associated with organic carbon that must have formed at low temperature and with water presence, which is in the range of habitable conditions.

The cherry on top in this intriguing analysis is that these minerals are not evenly distributed across the mudstone but are clustered in specific zones. The distribution, together with the minerals and carbon features within a sedimentary rock formed in the presence of water, supports the idea that maybe there was life on Mars.

“Our analysis leads us to conclude that the Bright Angel formation contains textures, chemical and mineral characteristics, and organic signatures that warrant consideration as ‘potential biosignatures,” the authors wrote in the paper.

The findings remain firmly on the first steps of NASA’s Confidence of Life Detection (CoLD) scale. That’s detecting a possible signal. The next three steps are ruling out contamination, making sure that the biology is possible, and ruling out a non-biological explanation.

“The fact that we had two things, we had organics present and these spots which on Earth are related to chemical changes in the rock, led us to suggest that this was what we call a potential biosignature,” Professor Sanjeev Gupta, part of the Perseverance team from Imperial College London, told IFLScience last year about the Cheyava Falls rock.

Here on Earth, those mineral signatures would be associated with microorganisms, and we have found evidence of bacteria that survive on cold lakes deep under the Antarctic ice – likely similar to the wet frigid conditions of ancient Mars. This doesn’t mean that there are no ways for those minerals to form without life. So, we should be excited about this sample without being overconfident that this is proof that there was life on Mars.

To truly understand the origin of these signatures, the team believes that we would need to analyze the samples on Earth. The Sapphire Canyon sample is sealed in a container to be taken back to Earth, but the Trump administration is trying to cancel the Mars Sample Return mission.

“Ultimately, the return of samples from Mars for study on Earth, including the Sapphire Canyon sample collected from the Bright Angel formation, would provide the best opportunity to understand the processes that gave rise to the unique features described here,” the team wrote.

The paper describing these new insights is published in the journal Nature.