New Delhi: The surface of the Moon and Mars are pockmarked by craters, as well as large impact basins preserving a record of cataclysmic strikes during the infancy of the Solar System. Even on Earth, there are such massive impact basins that still survive, despite billions of years of destructive geological processes such as plate tectonics and weathering by wind, water and life forms. Venus contains some of the most pristine impact craters in the Solar System, but has mystified scientists with an obvious lack of large impact basins. Researchers believe that they have now discovered large impact basins on Venus, hiding in plain sight.
The rings in the Haastte-baad Tessera indicated by a synthetic aperture radar map on top and a geologic map on the bottom. (Image Credit: Lopez et al., 2024).
The researchers examined one of the oldest regions on Venus, the Haastte-baad Tessera. The region is cut by concentric rings that can be over 1,500 kilometres wide. The researchers were able to determine that the features on the Venusian surface were caused by back-to-back impact events. Apparently, the conditions in an early Venus prevented the impact basins from appearing similar to such structures on the Moon and Mars. The research indicate that not all impact craters look alike. A paper describing the findings has been published in the Journal of Geophysical Research: Planets.
A young Venus had a thinner crust
Tesserae are heavily deformed terrain on Venus that can be identified by the wrinkles and corrugations. Such features are formed when thin, but strong material forms over a weak layer that flows and convects, like molten rock or lava. In the infancy of Venus, the crust was much thinner than it is today, and an impactor could have punched through the lithosphere into the mantle beneath, releasing the lava onto the surface that would have then cooled to create the observed tesserae. The researchers believe the impact events took place between 1.5 and 4 billion years ago. India is collaborating closely with Sweden, Germany and Russia for its first planetary science mission to Venus, Shukrayaan.
