🪐 These landforms show that Venus could still be active

Venus is generally described as a geologically frozen planet. However, the shape of several large valleys shows that tectonic activity may still be present, or may have continued until very recently on a geological timescale.

A team studied three rift valleys located in the regions of Ganis, Dali, and Devana Chasmata. These structures correspond to areas where the crust is stretching and fracturing. Their lateral reliefs exhibit a width and shape that are difficult to explain by very ancient activity.

Researchers compared Venus's topographic data with numerical models of rift formation. These simulations describe the evolution of a crust subjected to progressive extension, then the transformations of the relief when this extension stops.

The results show that the observed reliefs resemble those of active or recently active rifts. Their width indicates that the fractures may have formed while the crust was still under significant stretching forces. The modeled rates reach 3 to 10 cm per year.

On Earth, erosion gradually modifies tectonic reliefs. Venus does not have a comparable water cycle, but its hot crust can slowly deform under the weight of the reliefs. This relaxation should flatten the rift borders after their activity ceases.

The persistence of very wide reliefs therefore indicates that some valleys are young, or that they remain active. The authors estimate that the structures studied may have evolved over the last tens of millions of years, a short duration for the planet's history.

This conclusion does not mean that Venus has plate tectonics similar to Earth's. Observations rather indicate localized crustal extension, probably related to the movements of hot material within the planet's interior.

Available data remain limited, as most detailed maps of Venus come from the Magellan probe, launched in the 1980s. Future missions could more precisely measure the reliefs and search for current signs of deformation or volcanism.