Mineral and elemental geochemistry of the arid Qaidam Basin for habitability evaluation at Zhurong landing region on Mars

As Utopia Planitia might have once stored a relatively large water body, the western edge of the Qaidam Basin (a dehydrated paleolake basin featured by various Mars-like landscapes) in the northeastern Tibetan Plateau is analogous to the supposed lake shoreline of the landing site of Zhurong. As evaporation intensified, salt types in water sources and dry soils within the Qaidam Basin transformed from (bi)carbonates to sulfates and chlorides associated with decreasing biological activity, as suggested by isotopic signatures [1]. Evaporite minerals (e.g., gypsum, halite, and polyhydrated sulfates) were abundant in the western Qaidam Basin. Using the engineering qualification model of Zhurong’s MarSCoDe payload in a simulated Mars environment platform, the contents of gypsum in Qaidam soils were calibrated based on mineralogical and short-wave infrared (SWIR) spectral results. Putative signals of sulfur and chlorine in laser-induced breakdown (LIBS) spectra were additionally investigated. Semi-quantitative assessments of several evaporite minerals were performed for spectral data acquired from the Zhurong landing area. Furthermore, our findings imply that LIBS-associated statistics and suites of spectrometers can be promising tools for in situ life detection on Mars or returned sample analyses in laboratories if biotic materials were present in a small measured region even at low biomass levels [2,3]. In future Mars missions, we recommend that the life detection strategy should consider regions with mineral products of water-rock reactions as landing zones, as they could offer more habitable environments that provide life-essential elements and energy sources and preserve organic matter or even traces of life [4].

References

[1] Shen, J., Huang, T., Zhang, H., Lin, W. (2024). Hydrochemical and isotopic characteristics of water sources for biological activity across a massive evaporite basin on the Tibetan Plateau: Implications for aquatic environments on early Mars. Science of The Total Environment, 935, 173442.

[2] Shen, J., Liu, L., Chen, Y., Sun, Y., Lin, W. (2022). Geochemical and Biological Profiles of a Quartz Stone in the Qaidam Mars Analog Using LIBS: Implications for the Search for Biosignatures on Mars. ACS Earth and Space Chemistry, 6(11), 2595-2608.

[3] Shen, J., Liu, L., Chen, Y., Lin, W. (2024). A suite of spectroscopic devices as a potential tool to discriminate biotic and abiotic materials with an igneous rock. Icarus, 407, 115804.

[4] Shen, J., Liu, C., Pan, Y., Lin, W. (2024). Follow the serpentine as a comprehensive diagnostic for extraterrestrial habitability. Nature Astronomy, 8, 1230-1236.