Changes in the Raman and Fluorescence Spectroscopic Signatures of Irradiated Organic‐Mineral Mixtures: Implications for Molecular Biosignature Detection on Mars

The search for potential molecular biosignatures on Mars is complicated by its harsh radiation environment that can alter or destroy the primary features diagnostic of an organic compound's origins. In this work, mixtures Mars-relevant minerals and material representing different types chemical states sedimentary common in terrestrial geologic record were irradiated with 200 MeV protons to simulate effect exposure galactic cosmic rays solar energetic particles over geological timescales characterized using a deep UV Raman fluorescence spectrometer analogous Scanning Habitable Environments & Luminescence Organics Chemicals (SHERLOC) instrument 2020 Perseverance Rover. We found ionizing generally results loss material's origins favor increasingly aromatic compounds macromolecules. However, these radiolytic effects be mitigated formation macromolecular structures are more resistant radiolysis compared individual compounds, potentially through associations specific enable increased polymerization. Based results, rocks observed SHERLOC associated non-aromatic and/or kerogen-like may indicate less radiolytically damaged should prioritized return as it retain some primary, features.