1 billion years of plate tectonics summed up in 40 seconds

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For the first time, researchers have been able to continuously reconstruct the history of plate tectonics over the last billion years. The short film resulting from this international research effort brings to light the waltz of the continents, the evolution of the boundaries between plates or the change in the division of ocean basins.

Planet Earth is a geologically active star. Indeed, on a scale of millions of years, the continents transform and move. This dance redraws mountain ranges as well as ocean basins or even the living world. In fact, over the geological ages, the face of the globe is constantly renewed. Today an ice desert, the Antarctic continent was once located near the equator, for example, and housed a tropical ecosystem.

Continuous and consistent reconstruction over the last billion years

Rebuild this story based on proxies is no small feat, especially when we go back to the Neo-Proterozoic over 500 million years ago. However, in a recent study, researchers were able to develop the first model to reveal the global evolution over the last billion years, and this, uninterrupted. The results condensed into a video of a few tens of seconds are fascinating to say the least. They show, among other things, how the plates move, but also how the boundaries between them evolve.

Distribution of continents, boundaries between plates and subduction zones (red triangulated lines) 1 billion years ago. In addition, the oceans are white. See the original paper for more details on these figures. Credits: Andrew S. Merdith et al. 2021.

Our planet is unique in the way it hosts life. But this is only possible because geological processes, like plate tectonics, provide a basis for planetary survival. », Notes Dietmar Müller, geologist at the University of Sydney (Australia) and co-author of the work. This plate tectonics proceeds at an extremely slow speed on the scale of a human life. More precisely, we are talking about a few centimeters per year at most. However, given the age of our planet, this speed is sufficient to have allowed continents to circulate around the globe.

Better and better defined plate tectonics

Planet Earth is incredibly dynamic, with a surface made up of constantly jostling plates in a way unique among known rocky planets. These plates move at the speed fingernails grow, but when a billion years is condensed into forty seconds, a fascinating dance unfolds. », Specifies Sabin Zahirovic, co-author of paper. ” Oceans open and close, continents disperse and periodically recombine to form huge supercontinents “.

tectonic plates
Same as before, but 500 million years ago. Note that at this time, the northern hemisphere is almost completely oceanic. Credits: Andrew S. Merdith et al. 2021.

How did researchers manage to go back so far in time without breaking down chronology, a common problem in this field? The author and his collaborators explain that over the past four years, they have carefully compiled and assimilated the data collected by many other researchers in various often inaccessible places around the world. ” This study is designed as a first step towards a detailed and self-consistent tectonic reconstruction for the last billion years », Indicates the paper in its summary.

Put simply, this comprehensive model will help explain how our home, planet Earth, became habitable for complex creatures. », Relates the main author, Dietmar Müller. ” Life on Earth would not exist without plate tectonics. With this new model, we are closer to understanding how much this beautiful blue planet has become our cradle. “. The short film is available on the link below.

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