Exploring Organic-mineral Evolution in Planetary Analogs: Insights from Hydrothermal Alteration of Aromatic Molecules and Mafic Minerals

Abstract Organic-mineral interactions are crucial drivers of diversity in abiotic systems on planetary surfaces. Despite their significance, the evolution of these systems, particularly the role of organic molecules in newly formed minerals, remains underexplored. In this study, we proposed new experiments on analogs to explore the interactions between organic molecules likely present in planetary environments and primary minerals. We examine interactions between aromatic benzyl-group compounds and igneous minerals (olivine, feldspar) under mid-temperature aqueous conditions, analogous to hydrothermal systems hypothesized to exist on early Martian and terrestrial environments. Using multiscale techniques—gas chromatography, infrared spectroscopy, mass spectrometry, X-ray diffraction, microscopy, and adsorption studies—we analyzed the analogs after 45 days at 100°C. The results reveal that the presence of minerals influences the distribution of newly formed organic compounds, for example, by promoting the formation of organic chelates. Minerals altered in the presence of organics formed secondary phases, such as phyllosilicates and amorphous materials resembling serpentines or smectites. Organic compounds impacted dissolution rates, secondary mineral parageneses, and porosity, enriching the diversity of hydrated mineral phases compared to mineral alteration without organic matter. Significant carbon and nitrogen were found filling mineral porosity (up to 7 wt% C), modifying physical properties compared to systems without organics. These findings highlight the pivotal role of organics in shaping mineralogy on planetary surfaces and underscore the need for broader studies of organic-mineral analogs to improve interpretations of in situ and remote organic detections in extraterrestrial samples.