Abstract

On Venus, the coexistence of large volcanic highlands interpreted as the surface expression of long-lived mantle plumes, alongside coronae, smaller features thought to be caused by transient thermal diapirs, remains enigmatic. Using numerical models of mantle convection with sharp and broad mineral phase transitions, we show that both scales of upwellings are generated in a stagnant lid planet with an interior temperature 400 K warmer than Earth's. The smaller plumes originate from a ~600 km deep internal layer that exists as a consequence of the different sequence of mineral phase transitions that occurs in warmer mantles. These models further produce essential features of Venus' geodynamics, including apparent large scale downwellings, variable heat flow and plains dynamic topography.