Hydrated silica deposits in the Syrtis Major volcanic complex on Mars could indicate a relatively recent habitable environment, suggests a study online this week in Nature Geoscience. The shape of the deposits, and their location in and around a volcanic cone, point to an origin in a hydrothermal system, which could have both harboured life and preserved its remains.

John Skok and colleagues analysed data obtained with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). They detected spectroscopic signatures that are consistent with hydrated silica near the Nili Patera volcanic cone — a relatively young volcanic feature on Mars. The researchers interpret the data as indicative of a recent hydrothermal system. On Earth, hydrothermal environments with silica formation are considered to have a significant potential for preserving microbial fossils.