Between 300 million and 1 billion years ago, a large space object crashed into the planet Venus, leaving behind more than 270 km in diameter. According to researchers at the university, this crater could tell us whether Venus had plate tectonics similar to Earth. This is stated in a study published in the journal Nature Astronomy.
The researchers used computer models to recreate the impact that formed the Mead crater, Venus’ largest impact basin. Mead is surrounded by two precipitous faults: a rocky ripple frozen in time after a blow that forms a basin. Models have shown that in order for these rings to be where they are in relation to the central crater, Venus’s lithosphere must be quite thick, much thicker than that of Earth. This discovery suggests that an Earth-like tectonic process, with continental plates drifting like rafts over a slowly shaking mantle, probably did not occur on Venus at the time of Mead’s impact.
“Venus probably had what is called a ‘stagnant lid’ during impact,” said Evan Bionnes, Brown’s graduate student and lead author of the study. “”Unlike Earth, which has an ‘active cover’ with moving plates, Venus appears to have been a single-plate planet, at least before this impact.”
On Earth, evidence of plate tectonics can be found all over the world. There are huge cracks, called subduction zones, where strips of the earth’s crust extend into the interior. Meanwhile, new crust forms in the mid-ocean ridges, where lava from deep within the Earth flows to the surface and solidifies. Data from the orbiting spacecraft revealed cracks and ridges on Venus that are a bit like tectonic elements. But Venus is covered in a dense atmosphere, making it difficult to finally interpret fine surface details.