Geophysical evidence for an active mantle plume underneath Elysium Planitia on Mars

Abstract

Although the majority of volcanic and tectonic activity on Mars occurred during the first 1.5 billion years of its geologic history, recent volcanism, tectonism, and active seismicity in Elysium Planitia reveal ongoing activity. However, this recent pulse in volcanism and tectonics is unexpected on a cooling Mars. Here, we present observational evidence and geophysical models demonstrating that Elysium Planitia is underlain by a ~4000-km diameter active mantle plume head. Plume activity provides an explanation for the regional gravity and topography highs, recent volcanism, transition from compressional to extensional tectonics, and ongoing seismicity. The inferred plume head characteristics are comparable to terrestrial plumes that are linked to the formation of large igneous provinces. Our results demonstrate that the interior of Mars is geodynamically active today, and imply that volcanism has been driven by mantle plumes from the formation of the Hesperian volcanic provinces and Tharsis in the past, to Elysium Planitia today.