Thermochemical Modelling of Fluid-Rock Reactions in Vera Rubin Ridge, Galecrater, Mars

Vera Rubin Ridge (VRR) in Gale Crater, Mars, is a ~200 m wide ~6.5 km long northeast- southwest resistant geomorphological feature on the northern slopes of Aeolis Mons (Mt. Sharp). Analysis of Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) orbital data showed that VRR has strong hematite spectral signatures. Hematite was confirmed in-situ at VRR with the Curiosity rover and has been shown to be present throughout the Mur- ray formation. VRR is stratigraphically continu-ous with the underlying Murray formation. Previous thermochemical modelling showed how hematite at VRR could have formed as the result of open-system weathering at high water/rock ratios. Here we use thermochemical modelling to investigate possible reaction pathways for the hematite-clay- bearing assemblage observed at VRR, starting from an identified least-altered (minimum clay content) Murray composition, and a Mars basal brine.