The huge potential of salt minerals deposits on Mars, to investigate the past planet’s climate and habitability

Kurzfassung

One important fraction of the sedimentary record on Mars is composed of evaporite minerals. This record has been mainly detected by orbital spectrometers (thermal, i.e., TES, THEMIS, and reflectance spectroscopy, i.e., OMEGA, CRISM) and in-situ lander and rover measurements (Viking, Pathfinder, Phoenix, MER, MSL). Moreover, the presence of alteration and saline minerals on Mars has been also detected in the SNC-type (Shergotty, Nakhla, and Chassigny) meteorites. Evaporitic minerals have most likely recorded the last presence of stable surface water on Mars. Therefore, the evaporite minerals detected across Mars, are, most probably, the last mineral assemblages to have been precipitated by ancient Martian waters. Analogue studies have shown that evaporites have the ability to preserve traces of extinct microbial life, particularly when mineralized by iron oxide; and under certain circumstances can also sustain adopted forms of extant life (i.e., halotolerant organisms). Constraining the physical and chemical conditions required to form and to preserve evaporite minerals on the surface of Mars is crucial in understanding the climate variation phases and past habitability conditions of this planet.