Tectono‐Magmatic Evolution of Asymmetric Coronae on Venus: Topographic Classification and 3D Thermo‐Mechanical Modeling.

Venus is the only other Earth‐sized planet in the Solar System but it does not exhibit evidence of plate tectonics that dominates geological processes on Earth. Surface deformation on Venus is mainly driven by mantle convection and plume‐lithosphere interactions, likely represented by the widespread development of the circular volcano‐tectonic features known as coronae. Here, we present a joint study of mission data analysis and 3D modeling of asymmetric coronae on Venus. We systematically analyze 155 of the largest coronae on Venus in terms of surface topography and morphology. We establish that 75% of those coronae are radially asymmetric, and further sub‐categorize them based on their adjacent topography. This analysis reveals that many asymmetric coronae are positioned at a topographic transition between a lowland and plateau (termed topographic margin). With state‐of‐the‐art 3D numerical models, we investigate the physical processes behind plume‐margin interactions on Venus. We find that several tectonic styles may be responsible for asymmetric coronae at topographic margins, including lowland‐sided subduction, plateau‐sided lithospheric dripping, and an embedded plume. The gradient in lithospheric strength across the topographic margin controls these tectonic styles, and larger gradients enhance lithospheric resurfacing and the lifetime of the coronae. We also find that the density increase associated with the basalt‐to‐eclogite phase change provides the extra negative gravitational force required for downgoing crust to be recycled into the mantle. The models presented in this study reproduce a wide set of asymmetrical corona features found on Venus and suggest that they are generally more long‐lived than symmetric coronae. Plain Language Summary: Venus surface tectonics and volcanism are very dissimilar to modern Earth and in particular show development of many hundreds of circular and oval‐shaped "corona" structures, ranging in size from 60 to nearly 2,000 km. Here, the 155 largest coronae on Venus are systematically analyzed in terms of surface morphology and topographic positioning. We establish that the vast majority of large coronae on Venus have asymmetric features and are positioned at a topographic margin. We present the first‐ever plume‐margin numerical models in 3D which show several tectonic styles of plume‐margin interactions on Venus. The styles depend on the lithospheric structure and the density change of crustal material at depth. Importantly, the models indicate that asymmetric coronae at topographic margins are longer lived structures that symmetric coronae. Key Points: A new topographic classification of large coronae on Venus reveals that most coronae are radially asymmetric and bound a topographic marginWe present 3D tectono‐magmatic models of plume‐margin interactions on Venus which reveal several geodynamic evolution scenariosLateral lithospheric changes and the basalt‐to‐eclogite phase change mostly control the tectonic styles and coronae activity lifetime [ABSTRACT FROM AUTHOR]