It was presumed by those who study planets that the external layer of Venus, Earth’s hotter counterpart, would continuously thicken due to an apparent absence of mechanisms capable of returning its crust to the planet’s core. However, a collective of planetary scientists hailing from The Open University, NASA’s Johnson Space Center, and the Lunar and Planetary Institute has put forth a novel hypothesis concerning crustal metamorphism, predicated on rock density and cyclical melting processes.
An artist’s concept of active volcanoes on Venus, depicting a subduction zone where the foreground crust plunges into the planet’s interior at the topographic trench. Image credit: NASA / JPL-Caltech / Peter Rubin.
The terrestrial lithosphere is composed of colossal plates that gradually shift, inducing folds and fractures through a phenomenon referred to as plate tectonics.
For instance, when two lithospheric plates converge, the less dense plate overrides the denser one, compelling it downward into the underlying stratum, known as the mantle.
This geological phenomenon, termed subduction, plays a crucial role in regulating the thickness of Earth’s crust.
As the lower plate descends, its constituent rocks undergo transformations driven by escalating temperature and pressure as it penetrates deeper into the planet’s interior.
These alterations are classified as metamorphism, which is recognized as a contributing factor to volcanic activity.
“In stark contrast, Venus possesses a singular, unbroken crust, with no observable evidence of subduction induced by plate tectonics analogous to Earth’s,” stated Dr. Justin Filiberto, deputy chief of NASA’s Astromaterials Research and Exploration Science Division at NASA’s Johnson Space Center.
Dr. Filiberto and his associates employed sophisticated modeling to ascertain that the planet’s crust averages approximately 40 kilometers (25 miles) in thickness, with a maximum extent of 65 kilometers (40 miles).
“This is surprisingly attenuated, considering the environmental conditions on Venus,” Dr. Filiberto remarked.
“Our models reveal that as the crust accumulates thickness, its basal portion achieves such a high density that it either fragments and reintegrates with the mantle or becomes sufficiently heated to undergo melting.”
“Therefore, despite the absence of mobile plates, Venus’s crust does indeed experience metamorphic processes.”
“This discovery represents a significant advancement in our comprehension of the planet’s geological processes and evolutionary trajectory.”
“This fragmentation or liquefaction can reintroduce water and essential elements into the planet’s interior, thereby fueling volcanic phenomena.”
“This presents a novel paradigm for the mechanisms by which material is recycled into a planet’s interior and offers an alternative pathway for magma generation and the incitement of volcanic eruptions.”
“This fundamentally reshapes our understanding of the interconnectedness of Venus’s geology, crust, and atmosphere.”
“The subsequent phase involves the acquisition of direct observational data pertaining to Venus’s crust to rigorously validate and refine these theoretical models.”
“Our current understanding of the extent of volcanic activity on Venus remains incomplete.”
“While we surmise considerable activity, and existing research supports this hypothesis, definitive confirmation necessitates further empirical data.”
The research findings have been published in the esteemed journal Nature Communications.
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J. Semprich et al. 2025. Metamorphism of Venus as driver of crustal thickness and recycling. Nat Commun 16, 2905; doi: 10.1038/s41467-025-58324-1
