Astronomie - Terrawatch: is this how plate tectonics gets started?


Planetary scientists studying images of Venus noticed remarkable similarities between lava plains on Venus and areas on Earth where tectonic plates interact


 The location of lava plains on Venus. Illustration: Paul Byrne/Nasa data


For those who don’t like New Year, be grateful that you live on Earth and not Venus. Although the days are long on Venus (equivalent to 116.75 Earth days), the years are short, and come around every 1.92 Venus days. With a surface that seized up hundreds of millions of years ago, temperatures of more than 460C, and clouds of sulphuric acid, this isn’t a friendly planet.

However, its crust may be more lively than we had thought. Images from the Magellan mission in the 90s showed narrow mountain ranges and valleys on the surface of Venus. Recently, Paul Byrne from North Carolina State University revisited these images and noticed that these ridges and valleys often surround low areas that were later filled with lava. These features reminded Byrne and his colleagues of the large chunks of continental crust on Earth, such as the Sichuan Basin in China, which pummel their surroundings and create mountains and valleys at their edges as they jostle around.

The planetary scientists speculate that the scorching temperatures on Venus might heat the crust enough to allow some parts to detach slightly from the underlying mantle, creating thin crustal blocks that can “jiggle” around, just like on Earth. 

“It may help us understand how plate tectonics gets started,” says Byrne, who presented his findings at the American Geophysical Union’s autumn meeting in New Orleans. More exciting still, Byrne and his colleagues noticed that some of the ridges cross into the lava plains they surround, suggesting that this jiggling has happened more recently. Could Venus be trying to break into a plate-tectonic dance?