Plot showing evolution of crustal thickness over time for mantle convection models of Venus with different yield strength
Evolution of crustal thickness over time for mantle convection models of Venus with different yield strength (line color) producing major overturns at different times (marked with squares). Venus may be quite similar to the result of simulations in blue or black. Credit: Uppalapati et al. [2020], Figure 8a
Source: Journal of Geophysical Research: Planets

The internal structure of Venus is probably quite similar to that of the Earth, but the surface is fairly young. It does not feature the global network of tectonic plates that mark our planet and, except for a few places called tesserae, has been essentially reset at some point within the last billion years.

Uppalapati et al. [2020] model convection in the interior of Venus and show under what circumstances the lithosphere remains unbroken (stagnant lid regime) or breaks down occasionally and is recycled into the planet’s interior (episodic-lid regime). They track volcanic activity in their model to predict how the thickness and age of the crust change over time and place, for comparison with observations from the planet. They show that lithosphere recycling events, although short-lived, lead to a range of surface ages that are consistent with the observed crater population. Also, the recycling events can preserve fragments of the thick crust that existed before the event resembling the crustal plateaus that host most tesserae.

Models of this sort have gained in realism over the last few years and can capture more and more of the geological complexity of planetary bodies. As we wait for future missions to return to Venus, models like these are key to further our understanding of the planet.

Citation: Uppalapati, S., Rolf, T., Crameri, F., & Werner, S. C. [2020]. Dynamics of lithospheric overturns and implications for venus’s surface. Journal of Geophysical Research: Planets, 125, e2019JE006258.

—Laurent G. J. Montési, Editor-in-Chief, JGR: Planets

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