Abstract EANA2026-32

Mars has long been considered as a prime target for astrobiological studies in our Solar System. Although its surface conditions today are inhospitable, there is growing evidence that Mars once hosted diverse habitable environments, including stable liquid water at its surface. The ancient delta–lake system at Jezero Crater has been targeted for investigation due to its fine-grained sedimentary deposits providing conditions ideal for the preservation of organic materials and potential signs of life.

Recent rover missions, such as Curiosity, have made groundbreaking discoveries including the detection of complex organic compounds in Gale Crater. In 2024, the Perseverance rover made a significant discovery detecting organic–mineral associations in fine-grained sedimentary rocks of the Bright Angel Formation in Neretva Vallis, Jezero Crater. Perseverance identified sub-mm scale nodules (“poppy seeds”) and mm-scale reaction fronts (“leopard spots”) enriched in ferrous iron phosphate and iron sulphide co-located with organic matter within the mudstone. These features have been designated as “potential biosignatures” and are, to-date, the most promising indicators that Mars could potentially have hosted ancient microbial life. However, because abiotic (non-biological) processes can also produce such features, their origins cannot be definitively confirmed without further research and the analysis of returned samples.

Terrestrial analogues are therefore used to interpret similar materials prior to sample return. We are investigating Permian reduction spots from the Littleham Mudstone Formation (South England) which hosts reduction spot phenomena similar to those observed by Perseverance and thus serves as a useful field analogue in understanding the formation processes for these redox-driven features.

Samples are undergoing analyses using a range of geochemical and imaging techniques to obtain microstructural, elemental and potential organic characterisation. Analytical techniques include optical and electron microscopy, Raman spectroscopy and XRF, the latter of which is also available on the Perseverance rover. This study aims to determine whether these reduction features contain organic material and assess any potential mineralogical–organic spatial associations that might aid in their interpretation. Results will be compared to Martian datasets to better understand whether biological processes lead to their formation.

By conducting this study on terrestrial analogues of reduction spots in terrestrial red beds, we will address a primary challenge facing astrobiology: whether reduction spots on Mars are a true biosignatures or the result of abiotic processes. This contributes to the interpretation of candidate biosignatures ahead of future Mars sample return.