Venus Geologically Active

Venus is Still Geologically Active, New Research Suggests

A team of researchers from the University of Maryland and the Institute of Geophysics at ETH Zurich has identified 37 active circular volcano-tectonic features called coronae on Venus.

Venus in real colors, processed from Mariner 10 images. Image credit: Mattias Malmer / NASA.

Venus presents a clear contrast of tectonic activity with the Earth, despite broadly similar interior structure and composition.

Perhaps due to high surface temperatures and its water-poor interior, Venus does not feature Earth-like plate tectonics at present.

Evidence of a warm interior and geologic activity dots the Venusian surface in the form of coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust.

But it was thought that the coronae on Venus were probably signs of ancient activity, and that the planet had cooled enough to slow geological activity in its interior and harden the crust so much that any warm material from deep inside would not be able to puncture through.

In addition, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate.

“This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes,” said co-author Professor Laurent Montési, a researcher in the Department of Geology at the University of Maryland.

Comparison of various corona morphologies on Venus with numerical simulations. Venusian coronae imaged by synthetic aperture radar (left), their topographic signature (middle) and one of the numerical models that produced a similar topographic shape (right). Image credit: Gülcher et al, doi: 10.1038/s41561-020-0606-1.

In the research, Professor Montési and colleagues used numerical models of thermo-mechanic activity beneath the surface of Venus to create high-resolution, 3D simulations of coronae formation.

Their simulations provide a more detailed view of the process than ever before.

“The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae,” Professor Montési said.

Global distribution of coronae identified as inactive or showing ongoing activity. The dashed lines contour the proposed areas of focused plume activity (red) or inactivity (white). Image credit: Gülcher et al, doi: 10.1038/s41561-020-0606-1.

The researchers found that at least 37 large coronae — including the largest Artemis corona — are active, providing evidence for widespread ongoing plume activity on Venus.

“The active coronae on Venus are clustered in a handful of locations, which suggests areas where the planet is most active, providing clues to the workings of the planet’s interior,” they said.

The findings were published online this week in the journal Nature Geoscience.

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A.J.P. Gülcher et al. Corona structures driven by plume–lithosphere interactions and evidence for ongoing plume activity on Venus. Nat. Geosci, published online July 20, 2020; doi: 10.1038/s41561-020-0606-1