As members of NASA’s forthcoming VERITAS (Venus Emissivity, Radio science, InSAR, Topography, and Spectroscopy) mission, Cascioli and his team are particularly interested in the high-resolution gravity data the spacecraft will provide. Study coauthor Erwan Mazarico, also at Goddard, will co-lead the VERITAS gravity experiment when the mission launches no earlier than 2031.
Mystery Coronae
Managed by NASA’s Jet Propulsion Laboratory in Southern California, Magellan used its radar system to see through Venus’ thick atmosphere and map the topography of its mountains and plains. Of the geological features the spacecraft mapped, coronae were perhaps the most enigmatic: It wasn’t clear how they formed. In the years since, scientists have found many coronae in locations where the planet’s lithosphere is thin and heat flow is high.
“Coronae are abundant on Venus. They are very large features, and people have proposed different theories over the years as to how they formed,” said coauthor Anna Gülcher, Earth and planetary scientist at the University of Bern in Switzerland. “The most exciting thing for our study is that we can now say there are most likely various and ongoing active processes driving their formation. We believe these same processes may have occurred early in Earth’s history.”
The researchers developed sophisticated 3D geodynamic models that demonstrate various formation scenarios for plume-induced coronae and compared them with the combined gravity and topography data from Magellan. The gravity data proved crucial in helping the researchers detect less dense, hot, and buoyant plumes under the surface — information that couldn’t be discerned from topography data alone. Of the 75 coronae studied, 52 appear to have buoyant mantle material beneath them that is likely driving tectonic processes.
One key process is subduction: On Earth, it happens when the edge of one tectonic plate is driven beneath the adjacent plate. Friction between the plates can generate earthquakes, and as the old rocky material dives into the hot mantle, the rock melts and is recycled back to the surface via volcanic vents.