Large-scale features of the crustal structure on Mars, including the hemispherical dichotomy and Tharsis, were established very early in planetary history. Geodynamical models for the origin of the dichotomy and Tharsis, such as lithospheric recycling and a plume from the core-mantle boundary, respectively, involve solid-state mantle flow and are difficult to reconcile with timing constraints. An alternative point of view is that the martian crustal asymmetry and Tharsis can be associated with the upwelling and spreading of large, impact-induced melt regions, i.e., local magma oceans.

While the local magma ocean–induced upwelling model satisfies timing constraints on dichotomy and Tharsis formation,...