Brine-driven destruction of clay minerals in Gale crater, Mars.

Bristow, T F; Grotzinger, J P; Rampe, E B; Cuadros, J; Chipera, S J; Downs, G W; Fedo, C M; Frydenvang, J et al. · Science · 2021

basic_science · Level V

Where this comes from

Abstract

Mars' sedimentary rock record preserves information on geological (and potential astrobiological) processes that occurred on the planet billions of years ago. The <i>Curiosity</i> rover is exploring the lower reaches of Mount Sharp, in Gale crater on Mars. A traverse from Vera Rubin ridge to Glen Torridon has allowed <i>Curiosity</i> to examine a lateral transect of rock strata laid down in a martian lake ~3.5 billion years ago. We report spatial differences in the mineralogy of time-equivalent sedimentary rocks <400 meters apart. These differences indicate localized infiltration of silica-poor brines, generated during deposition of overlying magnesium sulfate-bearing strata. We propose that destabilization of silicate minerals driven by silica-poor brines (rarely observed on Earth) was widespread on ancient Mars, because sulfate deposits are globally distributed.