High flow capacity and low viscosity of the Séítah formation, at Jezero Crater, Mars

The unexpected discovery of olivine cumulate at the Séítah Formation within Jezero Crater was one of the most compelling findings of the Mars2020 Perseverance rover mission thus far. Compared to Earth, Mars is a basaltic world and differences in gravity, atmosphere and volatile content imply commensurate changes in lava flow dynamics that need to be better understood. We use rover geochemistry data to calculate the viscosity and relative flow distance of the Séítah unit and its parental lava. We suggest the olivine cumulate discovered by the rover was related to a ponded lava flow, based on the low viscosity and distribution of the unit. We estimate an approximate relative depth for the cumulate layer of the lava pond using a convective lava magma model. We also compare the Noachian Jezero olivine rich viscosities to Hesperian basalts analysed by Spirit, and find the Noachian samples to have a greater propensity to flow than their younger cousins. Future observations of the olivine rich unit and laboratory studies of the samples collected by Mars2020 will provide a deep window into the flow dynamics and evolution of Martian lava flows.