A terrestrial model for an alkaline martian hydrosphere

The chemical evolution of the early hydrospheres on Earth and Mars could have been similar. It may have been characterized by long-lasting highly alkaline conditions. By analogy with sediments produced in terrestrial highly alkaline environments (soda lakes), traces of the martian alkaline hydrosphere could be found by remote sensing and/or landing missions in form of (i) CaMg carbonate precipitates, (ii) silicified deposits, (iii) volcanogenic natrocarbonatites, and (iv) efflorescenses. The potential significance of the highly alkaline Mars hydrosphere for the origin, sustenance, and subsequent evolution of living systems on that planet is discussed.