Often referred to as the Earth’s “twin planet,” Venus presents a stark contrast in surface conditions, atmospheric composition, and structural characteristics. Gaining insight into the internal mechanisms that shape Venus’s surface remains a key objective in planetary science.
The Earth’s surface is perpetually reshaped through the continual movement and recycling of vast sections of the crust, known as tectonic plates, which float above the viscous mantle.
Unlike Earth, Venus lacks tectonic plates, but its surface is still influenced by molten material rising from beneath.
To better comprehend the processes underlying these transformations, scientists have examined structures known as corona.
With sizes ranging from dozens to hundreds of kilometers, coronae are primarily formed where hot, buoyant mantle material ascends and pushes against the lithosphere above.
These features generally exhibit an oval shape and are surrounded by a concentric fracturing pattern.
Researchers estimate that hundreds of coronae are present on Venus.
Utilizing archival data from NASA’s Magellan mission, Dr. Gael Cascioli from the University of Maryland and colleagues identified signs of surface or subsurface activity that significantly shaped many of Venus’s coronae.
“Coronae are not observable on Earth today. However, it is conceivable that our planet’s early history included formations before the advent of plate tectonics,” stated a recent paper published in the journal Advances in Science.
“By integrating gravity and topographical data, this research has provided critical new insights into the subterranean processes that likely continue to influence Venus’s surface today.”
Launched in 1989, Magellan employed a radar system to penetrate Venus’s dense atmosphere and create detailed maps of its mountainous and plain terrains.
Among the various geological features mapped, coronae were notably enigmatic, with their formation remaining initially unclear.
Since then, planetary scientists have detected numerous coronae in regions where the lithosphere is thin and geothermal activity is high.
“Coronae are plentiful on Venus, representing significant features, and over the years, multiple theories have been proposed concerning their formation,” remarked Dr. Anna Gürcher, a researcher at the University of Bern.
“The exciting aspect of our research is that we can now assert that ongoing activity processes driving their formation are highly probable.”
“We hypothesize that similar processes may have also taken place early in Earth’s history.”
Researchers have developed advanced 3D geodynamic models illustrating different scenarios for the formation of plume-induced coronae, which were then compared with Magellan’s gravity and topographic data.
Gravity data has proven instrumental in enabling researchers to detect low-density regions below the surface and identify buoyant structures at elevated temperatures, something that topographical data alone cannot reveal.
Of the 75 coronae analyzed, 52 exhibited buoyant mantle materials beneath them, suggesting potential for significant structural processes.
One critical process is subduction. On Earth, this occurs when one tectonic plate is pushed beneath another.
Friction between plates can induce earthquakes, and as older rocky material descends into the hotter mantle, those rocks melt and re-emerge at the surface through volcanic activity.
On Venus, various forms of subduction are suspected to happen around several coronae.
In this context, hot rock buoyancy within the mantle forces material into the lithosphere, resulting in surface material rising and spreading outward, colliding with surrounding areas and pushing some material back down into the mantle.
Additionally, another structural process known as lithosphere drip may exist, with denser cold materials sinking from the lithosphere into the heated mantle below.
Several locations have also been identified where a third process might be occurring, where molten rock plumes beneath thicker areas of the lithosphere could potentially drive volcanic activity above.
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Frog Casioli et al. 2025. Spectra of structural processes in Venus’ coronae revealed by gravity and topography. Advances in Science 11 (20); doi:10.1126/sciadv.adt5932
Source: www.sci.news
