Multipolarized radar reveals shallow subsurface structure and middle-late Amazonian aqueous activity in Utopia Planitia, Mars

The Martian subsurface preserves a record of the geological and climatic evolution of Mars beyond that exposed at the surface. The Zhurong rover of the Tianwen-1 mission landed in southern Utopia Planitia on Mars and conducted a high-frequency quad-polarized ground-penetrating radar survey. High-frequency radar images with ∼5 cm vertical resolution in the immediate subsurface reveal three distinct subsurface layers, buried craters, centimeter-scale layered sediments, and widespread northward-sloping features, some of which likely formed in aquatic environments during the middle to late Amazonian period. These findings suggest that aqueous activity in Utopia Planitia persisted throughout this period, extending the known timeline of water-related processes on Mars and providing new insights into the red planet’s geological and climatic evolution.