Venus is famous for its “pancake domes” — steep-sided volcanoes that rise from the planet’s surface like circular welts.
Volcanoes are common across Venus, with more than 1,600 large volcanoes or volcanic features discovered so far.
Eventually, the lava stops moving and solidifies, forming the pancake domes.
Indeed, a 2021 study found such flexural signatures surrounding one-fifth of a sample of Venusian pancake domes.
In particular, the flexible crust’s domes had flat tops and very steep sides, characteristic of the pancake domes.
The formula for Venus’ enormous pancakes may finally have been figured out by scientists.
Steep-sided volcanoes known as “pancake domes” that rise from the planet’s surface like round welts are what make Venus famous. According to a recent study, the planet’s upper crust, which appears more flexible in some places, may have shaped these odd dome-shaped formations to some extent.
There are many volcanoes on Venus; to date, over 1,600 large volcanoes or volcanic features have been found. The so-called pancake domes, which resemble a flattened version of Hawaii’s Mauna Loa and are disk-shaped structures that span tens of miles but are only half a mile high, are among the more fascinating varieties.
It’s still unclear exactly how these volcanoes form and what materials make them up. One theory is that they form from slow-moving, extremely sticky lava that moves due to its own weight (a phenomenon known as a viscous gravity current in technical terms). When the lava eventually stops flowing and solidifies, the pancake domes are created.
Madison Borrelli, a postdoctoral researcher at the Georgia Institute of Technology and the study’s first author, told Live Science via email that the formation of the domes is likely not solely dependent on the type of lava. One element that was overlooked in many earlier studies was Venus’ upper crust’s flexure, or bendiness.
As it happens, the surface of Venus and Earth behaves in some places similarly to the skin of an orange: when subjected to a heavy enough load, the surfaces dimple. If this type of dimpling was present when the pancake domes formed, it would leave behind some obvious indicators, such as a bulge around the dome where the crust gave way upward. Indeed, a study conducted in 2021 discovered these flexural signatures around one-fifth of a sample of pancake domes from Venus.
Related: NASA data from 30 years ago may be reanalyzed to show that Venus is geologically “alive” after all.
Borrelli and her colleagues from French and American universities wanted to know how a bendy crust might impact the creation of a pancake dome. S. centered on the Narina Tholus, an 88.5-mile-wide (55-kilometer) dome situated around the Aramaiti Corona, one of the numerous enormous oval formations that pockmark Venus’ surface. This was the only dome for which they had high resolution data.
The researchers used topographical data gathered by NASA’s radar-wielding Magellan mission in the 1990s to create a virtual model of the Narina Tholus dome, which was published on May 10 in the Journal of Geophysical Research: Planets. Before comparing the outcomes to the virtual dome, they replicated viscous gravity currents of lavas with varying densities on top of a rigid lithosphere and a flexible upper crust.
According to the study’s findings, domes formed on a flexible crust resembled the virtual pancake dome significantly more than those formed on a rigid lithosphere. Specifically, as is typical of pancake domes, the flexible crust’s domes had flat tops and extremely steep sides. The researchers explained this by saying that the lava builds up because the bulge surrounding the dome stops it from flowing any farther. The flexural signatures of the bendy lithosphere’s domes resembled those of Narina Tholus.
The dimpling of the lithosphere, however, was not sufficient to account for the domes’ characteristics; the density of the lava also played a role. Despite producing domes with the proper shape, low-density lavas produced smaller crustal bulges than those found close to the actual pancake dome. Only lavas with densities greater than 0.0867 lbs per cubic inch (2,400 kg/m3), or more than twice the density of room temperature water, produced the proper flexural signatures and dome shapes. The domes were formed over hundreds of thousands of Earth-years by the settlement of these high-density lavas, which were more than a trillion times more viscous than room-temperature ketchup.
The primary flaw in the study, however, is that it only used data from the Narina Tholus dome. In order for the researchers to test their model with more data, Borrelli hopes that future missions to Venus, such as NASA’s VERITAS program, will provide higher resolution topography of the planet’s surface.
The researchers were unable to identify the precise kind of lava that creates the pancake domes, but the new information may help. The majority of Venusian volcanoes seem to emit basaltic lava resembling that of Mauna Loa, but the researchers were unable to rule out rhyolitic and andesitic lavas, which resemble those that emanate from Mount St. Helene.
