Evolution History of Mesas in the Southern Utopia Planitia and Implications for the Ancient Oceans on Mars

As one of the prominent landforms in the Zhurong landing region, mesas are geological features with flat tops and steep marginal cliffs. The mesas are widely distributed along the dichotomy boundary. There are various interpreted origins proposed for the mesas, such as the erosion of sedimentary layers, tuyas eruptions, or surface collapse due to the catastrophic release of groundwater. We investigate the detailed morphological characteristics of the mesas on the Late Hesperian Lowland unit within the Utopia Planitia. We observe morphological evidence for both the ice-bearing interior mesas and the sedimentary origin, including (1) small pits on the crater wall and mesa cliff formed by the release of volatiles like ice; (2) lobate flows at the base of mesas formed by the melting of subsurface ice; (3) layered mesas indicating sedimentary origin; (4) grooves on the top surface of mesas formed by the volumetric compaction of sedimentary deposits. The results indicate that the mesas in the study area are formed by the erosion of sedimentary layers and representative of the Noachian oceanic sediments. We propose an evolutionary model for the mesas. This study will provide some insights into future research of ancient ocean hypothesis of Mars and interesting targets for the exploration of the Zhurong rover.