Abstract

The pressure and temperature conditions on planet Mars have probably never permitted the presence of liquid water at its surface, as witnessed by unaltered olivines of any age since the Naochian. Nevertheless, iron sulphates at the surface suggest hydrothermal activity at some point in time and space, arguably at depth, from where minerals were expulsed by volcanic activity and/or “sweating out” during phases of heating upon meteorite impacts. Beneath the cryosphere, at depths between 4 and 10 km, the reigning P–T conditions meet the stability conditions of water and vapour, originating from a degassing magma. The sulphate dominance in Mars’ mineralogy mimics the terrestrial analogues of hyperacid and hypersaline fluids and minerals hosted in Earth’s most extreme crater lakes (e.g. Kawah Ijen, Poás, Copahue, Ruapehu, White Island) and ore depositing systems (e.g. high-sulphidation and porphyry systems). The observed similarity enables a bidirectional learning process for future research: on one hand, the more extreme systems on Mars can teach us on how highly active magmatic-hydrothermal and ore depositing systems on Earth might work; on the other hand, metal transport and deposition at terrestrial systems opens perspectives for “space mining” on Mars.