Venus: The Coronae Enigma and Lessons for Earth

Venus hosts hundreds of enigmatic circular tectono-magmatic features known as coronae, whose origins, activity state, and role in planetary heat loss remain among the most persistent open questions in Earth and planetary sciences. Coronae display extraordinary diversity in size, morphology, topography, gravity signatures, and tectonic setting, indicating that they do not represent a single formation mechanism, but instead reflect a spectrum of dynamic processes. Understanding these structures is critical not only for deciphering Venus’ geodynamic regime, but also for assessing whether similar processes may have operated on the early Earth before, or during, the onset of sustained plate tectonics.

Here, we present new insights into the coronae enigma by integrating results from a newly compiled global corona database with joint analysis of topography and gravity observations, complemented by recent three-dimensional thermo-chemical geodynamic modeling. The updated database includes 741 coronae, substantially more than previously catalogued features, enabling a more accurate global-scale statistical assessment of coronae morphology, geological setting, and spatial distribution. The expanded dataset reveals numerous corona(-like) structures not previously recognized and highlights systematic variations in corona expression across different tectonic environments.

We investigate the topography and gravity signatures of the largest coronae using Magellan datasets. By analyzing free-air gravity anomalies together with key topographic characteristics, we identify distinct classes of coronae that exhibit signatures consistent with buoyant mantle support and different styles of plume–lithosphere interaction, including scenarios in which crust is recycled back into the mantle through lithospheric delamination or subduction-like processes. Importantly, our analysis further reveals that the limited spatial resolution of the Magellan gravity field can obscure or suppress positive gravity anomalies beneath some coronae, particularly where deep annular troughs surround an uplifted interior. This suggests that a subset of potentially active coronae could be effectively “hidden” in current geophysical datasets. These coronae therefore represent key observables for forthcoming missions such as ESA's EnVision and NASA's VERITAS.

Finally, we explore how corona-formation models are relevant to early Earth evolution.  These results provide a framework for evaluating plume-induced lithospheric weakening and transient subduction-like behavior as key mechanisms for the onset of plate tectonics on our planet.