Venus, often called Earth’s evil twin, is home to some of the most peculiar geological features in the solar system. Among its many mysteries are the planet’s so-called pancake domes—enormous, circular volcanic formations that resemble oversized flapjacks left to cook on Venus’ searing surface. While scientists have long believed these domes were created by the slow oozing of thick, viscous lava, new research points to another essential factor.
Testing A New Theory With A 90-mile-wide Dome
A team of scientists recently revisited this question by modeling one of the largest known domes on Venus—Narina Tholus, which spans nearly 90 miles (145 kilometers) in diameter. Using radar data collected by NASA’s Magellan mission in the 1990s, they constructed a detailed digital model of the structure to explore how different lava properties and surface behaviors might affect its shape.
Their simulations revealed that lava alone could not account for the dome’s flattened top and sharply sloped edges. Instead, the presence of crustal flexure—the ability of Venus’ lithosphere to bend under pressure—played a critical role. According to the researchers, when more flexure is present, “dome tops become flatter and sides steeper.”
This effect causes lava to pile up and stop spreading once it encounters a soft, deformable crust, shaping it into a classic pancake dome. But is the formation of these domes solely determined by the type of lava? Probably not, according to Madison Borrelli, a postdoctoral researcher at the Georgia Institute of Technology and lead author of the new study, who explained by email to Live Science.
Venus’ Ultra-thick Lava And Its Geological Signature
Not just any lava fits the mold. The models only worked when they used ultra-dense, highly viscous lava—a substance more than a trillion times thicker than ketchup and twice as dense as water. Such lava would flow extremely slowly, potentially taking hundreds of thousands of Earth years to settle into a final shape. This type of lava also reproduced the crustal bulges seen around some domes, which had been observed in previous studies but not fully explained until now.
The way this lava behaves when encountering a pliable crust leads to formations with flat summits and steep flanks, mimicking many of the pancake domes scattered across Venus. The study’s success in replicating these features using both dense lava and a bendy lithosphere marks a step forward in understanding the planet’s volcanic history.
The Truth About Venus? Coming Soon
While the study offers compelling evidence for this new formation mechanism, it’s currently based on a single dome. Broader confirmation will rely on upcoming missions such as NASA’s VERITAS and DAVINCI, which are set to deliver improved topographic data and geological insights from Venus’ surface. These missions aim to investigate thousands of other volcanic features and test whether the same crust-lava interactions are at play across the planet.
If validated, the findings could reshape our understanding of Venus’ evolution, offering clues about why it diverged so dramatically from Earth, despite their similar size and composition.