Abstract EANA2025-98

Terrestrial hot springs have existed throughout Earth’s history and preserved some of the oldest evidences of life on our planet.  Recent studies (Teece et al., 2024) suggest that signatures of ancient hydrothermal springs could potentially be identified on Mars, highlighting their significance in the search for past habitability, a subject of increasing interest in astrobiology. Given the higher fidelity of microorganisms associated with terrestrial hot spring minerals, these specific sites on Mars also possess significant habitability and preservation potential. Among these, carbonate-rich hot springs, commonly known as travertines, offer a unique window into biosignature formation and preservation. These environments exhibit a wide range of mineral-microbe interactions, particularly between carbonate minerals, such as calcite and aragonite, and thermophilic microbial communities. Carbonate hot springs, both terrestrial and submerged, host diverse mineral-microbe assemblages and serve as valuable terrestrial analogs for planetary exploration. High-altitude hydrothermal systems, such as the Tapovan hot springs in the Uttarakhand Himalayas, India, are especially relevant in assessing the habitability of ancient Martian terrains. Located within the tectonically active Higher Himalayan Crystalline zone, Tapovan experiences deep crustal heating, meteoric water infiltration, and extensive water-rock interactions, leading to the precipitation of travertine dominated by calcite and aragonite. These calcium carbonate polymorphs form under specific physicochemical conditions, governed by temperature, pH, CO₂ degassing rates, and Mg²⁺ concentrations, with microbial activity often playing a significant role. Rapid CO₂ loss favors rhombohedral calcite precipitation, while elevated temperatures and magnesium promote acicular aragonite formation. The in-situ identification of hydrothermal opaline silica on Mars, associated with hot springs, fumaroles, or basalt leaching, suggests that hydrothermal springs may be more prevalent on Mars than previously thought. Recent orbital data reveal geological structures, particularly in Vernal Crater and Arabia Terra, that could be remnants of ancient springs (Oehler et al., 2020). The discovery of carbonates in Gale and Jezero Craters has renewed interest in the potential for carbonate-hosted hot springs and hydrothermal activity within paleolake settings. It is plausible that marginal carbonates along the rim of Jezero Crater formed through low-temperature hydrothermal processes, akin to terrestrial travertine systems. Preliminary investigations in the Central Himalayan region, specifically Tapovan hot springs, indicate the presence of calcite and aragonite. This study will highlight how the mineralogical characteristics and formation conditions of Tapovan travertines can improve our understanding of potential biosignature preservation in ancient Martian hydrothermal systems.

 

References:

1. Teece, B.L., Havig, J.R., Hamilton, T.L., Barge, L.M., 2024. Geochemical context for hydrothermal organic molecules in Mars-analogue samples from Earth. Nat. Astron. 8, 1513–1520.
2. Oehler, D., Allen, C., Osinski, G., 2020. Potential Hot Spring Deposits in Vernal Crater, Mars: Exceptional Candidates for Future Exploration, in: 51st Annual Lunar and Planetary Science Conference. p. 1563.