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Abstract EANA2024-56


Preservation of organic matter on Mars: a study of sulfate minerals' protective properties

Francesco Renzi (1), Teresa Fornaro (2), Andrew Alberini (2)(3), Sole Biancalani (2)(3)(4)(5), John R. Brucato (2), Cristina García Florentino (2)
(1) University of Pisa, Pisa, Italy, (2) INAF-OAA, Florence, Italy, (3) University of Florence, Florence, Italy, (4) Italian Space Agency, Rome, Italy, (5) University of Trento, Trento, Italy


Numerous exploration missions currently concentrate on Mars, seeking evidence of past life and establishing it as a significant target in astrobiological research. Nowadays Mars has uninhabitable conditions but observational data strongly indicate that it once had the essential conditions for life. It likely featured an environment similar to early Earth, with hydrological systems, varied geological formations, and a dynamic atmosphere. The primary criterion for assessing the astrobiological significance of Mars obtained by exploration programs is the presence of minerals with a high potential for preserving biosignatures and organic matter. Martian surface is constantly irradiated by solar ultraviolet (UV) photons in the 200-400 nm wavelength range and cosmic rays, that can alter organic matter [1]. The most intense signals have been detected, likely due to aromatic organic compounds associated with minerals that have undergone significant aqueous processing, such as sulfates and carbonates [2][3]. In this study, we explored the potential photoprotective effects of magnesium sulfate and calcium sulfate on organic compounds likely present on Mars, such as 9-methylanthracene and 1,3-dihydroxynaphtalene. We prepared Martian analog samples to simulate a potential natural interaction in an early Martian aqueous environment between magnesium and calcium sulfate and these organics, followed by a plausible desiccation event [4]. These analog samples were characterized using a Bruker VERTEX 70v FTIR interferometer (Diffuse Reflectance Infrared Fourier Transform, DRIFT) to investigate potential molecule-mineral interactions. They were also irradiated with a Newport Xenon enhanced UV lamp to assess the stability of the organics when adsorbed onto magnesium and/or calcium sulfate.

 

References: [1] Fornaro T. et al. (2018), Life, 8(4), 56. [2] Scheller E. L. et al. (2022), Science, 378(6624), 1105-1110. [3] Sharma S. et al. (2023), Nature, 619(7971), 724-732. [4] Fornaro T. et al. (2020), Frontiers in Astronomy and Space Sciences, 7, 539289.