The large, circular geological features on Venus are called coronae. The name comes from the Latin word for “crown,” reflecting their broad ringed or crown-like appearance when viewed in radar images.
Venusian coronae are typically hundreds of kilometres across and are marked by concentric fractures, ridges, and volcanic features. Scientists generally think they form when hot material rises from the mantle and pushes the crust upward into a dome. As the structure cools or collapses, magma may escape around its margins, leaving a complex circular landscape.
Coronae were recognized in detail after radar observations by the Soviet Venera 15 and Venera 16 spacecraft in the early 1980s. Later, NASA's Magellan mission revealed thousands of kilometres of geological detail and showed how coronae fit into Venus's broader history of volcanism and crustal deformation.
The alternatives describe different feature types. Dorsa are ridges, rupes are escarpments or scarps, and tesserae are heavily deformed highland terrains. Coronae are unusual beyond Venus: similar crown-like structures are also known on Uranus's moon Miranda.