Abstract_EANA2024-42

Abstract EANA2024-42

Exploring Martian soil on Earth: characterizing Icelandic potential regolith analogs

Sole Biancalani (1)(2)(3)(4), Teresa Fornaro (4), Andrew Alberini (3)(4), Cristina García Florentino (4), Giovanni Poggiali (4)(5), Giovanni Pratesi (3), Micol Bellucci (2) and John Robert Brucato (4)

(1) University of Trento, Trento, Italy, (2) Italian Space Agency, Rome, Italy, (3) University of Florence, Florence, Italy, (4) INAF-Astrophysical Observatory of Arcetri, Florence, Italy, (5) LESIA-Observatoire de Paris PSL, Université Paris Cité, Sorbonne Université, Meudon, France

Mars is currently the focus of numerous exploration missions to search for traces of possible past life, making it one of the most interesting astrobiological targets. Although it is now characterized by extreme and inhospitable conditions, observational evidence indicate that Mars was once habitable and had probably host an Earth-like environment with similar hydrological, geological, and atmospheric complexity. Currently, the Perseverance rover is taking several types of measurements at Jezero Crater to gain insight into Martian geology, atmosphere, and potential presence of biosignatures. In particular the VISIR spectrometer of the SuperCam instrument suite, and SHERLOC, a UV Raman and fluorescence spectrometer, are being used to analyze the Martian regolith in order to understand its mineralogical composition and to detect chemicals, organic molecules and potential biosignatures.

The study of the oldest rocks of the planet, which are available on the surface due to the lack of plate tectonics, has the potential to reveal traces of past life (Williford et al. 2018), and might help to define approaches and strategy to support in situ analyses of Perseverance and future sample return missions. The present study aims to characterize a potential regolith analog collected at Lambahraun, Iceland, during the NASA-ESA Mars Sample Return Sample Analogue Campaign. The site was selected just south of the original target field based on previous work by Baratoux et al. (2011) and Mangold et al. (2011). The sampled sand sheet was chosen for its similarity to the images of the Jezero crater regolith, and presents fine to medium basaltic sand with some coarser grains. Samples were collected with sterilized tools to keep them organically clean.

The characterization of the sample was performed at the Arcetri Astrobiology Laboratory of the INAF-Astrophysical Observatory of Arcetri using a Bruker VERTEX 70v FTIR spectrometer to perform DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) measurements. We acquired laboratory spectra in the range between 8000cm-1 and 400cm-1 (1.25μm–25μm) with a resolution of 4cm-1. The sample compartment was saturated with N2 to reduce atmospheric absorption during the measurements.

We will present the characterization of the Icelandic samples and the comparison with the spectra acquired by the Perseverance rover at the Observation Mountain (sol 593-606 and sol 632-641) on Mars. In the SuperCam range (1.25 μm-2.6 μm), the spectra of our samples showed similarities to those of Mars, and the MIR spectra confirmed their basaltic nature. This work will be useful to understand if this sample is a good analog for the Jezero crater soil, in order to use it as a substrate to study the interactions between organic molecules, mineral substrate and radiation in Martian-like conditions. Furthermore, since the spectral data suggest the presence of a very small amount of organics, a continuation of this study might include TOC analysis and organic extraction on the same Icelandic soil samples, simulating potential small organic traces on samples returned from Mars.

References:

Baratoux D. et al., 2011, ESPL, 36(13), pp.1789-1808.

Mangold N. et al. 2011, EPSL, 310(3-4), pp.233-243.

Williford K. H. et al., 2018, Elsevier,275–308.