Geospatial analysis of Andean microbialitic systems as analogues for the search for life on Mars

Abstract

Identifying terrestrial analogues that constrain the limits of habitability is essential for interpreting Martian paleoenvironments and guiding life-detection strategies. High-altitude Andean lakes host microbialites that develop under polyextreme conditions, intense ultraviolet radiation, high salinity and alkalinity, strong evaporation, and volcanic influence, making them valuable analogues for early Mars. This study integrates GIS-based geomorphological analyses with hydrological, geochemical, and mineralogical data to evaluate controls on microbialite development in three lakes of northwestern Argentina: Peinado, Laguna Verde, and Carachi Pampa. Basin geometry, alluvial fan morphology, elevation gradients and hydrological variability (permanent vs. seasonal lake area) are quantified and linked to water chemistry, mineralogy, and microbialite characteristics. Results show that microbialite development is greatest in Peinado Lake, characterized by lower electrical conductivity (~ 65 mS/cm), reduced hydrological variability (permanent/seasonal ratio ~ 1.9), and steeper alluvial fan slopes (~ 4.7%), favoring sustained carbonate precipitation and long-term growth. In contrast, Laguna Verde and Carachi Pampa Lake exhibit higher conductivity (> 450 mS/cm), stronger seasonal variability (ratios up to ~ 17), and flatter geomorphology, conditions associated with limited microbialite development and predominantly evaporitic (gypsum-rich) assemblages. PCA indicates that hydrological variability, salinity, and geomorphology explain most inter-lake differences (> 60% variance). These findings demonstrate that key controls on microbialite formation can be approximated using DEM-derived parameters and basic geospatial datasets, providing a first-order framework for planetary exploration and biosignature targeting. High-altitude Andean lakes host microbialites that develop under polyextreme conditions, intense ultraviolet radiation, high salinity and alkalinity, strong evaporation, and volcanic influence, making them valuable analogues for early Mars.