^1,2,3Scott M. Perl, ^2,4Aaron J. Celestian, ⁴Frank A. Corsetti
Journal of Geophysical Research: Planets 131, e2026JE009730 Link to Article [DOI: 10.1029/2026JE009730]
¹Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA
²Mineral Sciences, Los Angeles Natural History Museum, Los Angeles, CA, USA
³Blue Marble Space Institute of Science, Seattle, WA, USA
⁴Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
Published by arrangement with John Wiley & Sons

Evaporite minerals can capture and entomb organic matter within their intercrystalline and intracrystalline structure because they precipitate relatively quickly (nomenclature adopted from Schopf et al. (2012), https://doi.org/10.1089/ast.2012.0827). Thus, evaporite minerals constitute a target for biosignature investigation on Earth and Mars, where evaporitic deposits are known to exist. However, little is known about the process of organic preservation and detection in evaporites, or the stability of such molecules when exposed to significant UV radiation as would be present on the surface of Mars. Here, we investigate the incorporation of β-carotene into halite (NaCl) by growing halite in the lab in the presence of know concentrations of β-carotene and examining the resultant precipitated crystals and fluid inclusions via Raman spectroscopy. Following brine evaporation, the experimental β-carotene-containing halite was exposed to UV-C to simulate conditions on the Martian surface. Results reveal that β-carotene has a strong Raman signature that remains intact even when entombed in halite. In particular, fluid inclusions within the halite displayed particularly strong β-carotene Raman signatures after UV-C exposure. Little change was observed even after several days of UV-C delivery. Our results reveal that complex organic molecules like β-carotene should be preserved well in halite (especially in fluid inclusions) and that halite does provide protection from organic matter degradation from UV-C radiation. Thus, evaporites constitute a good target for the search for biomarkers on Mars. These findings will allow for proper criteria for the discovery of any potential physical biosignature and chemical biomarker that would be on active ocean worlds (Europa, Enceladus) and for future Mars subsurface drilling missions.