The continents were already moving 4 billion years ago

September 27 () –

An examination of rocks in Canada suggests that 4 billion years ago, plate tectonics probably looked more like what we experience today than scientists considered.

Published in Proceedings of the National Academy of Science (PNAS), The research studied the mineral zircon from two of the oldest pieces of intact crust, dating between 4 billion and 2.7 billion years old, and found that ancient plate tectonics, or how continents move and interact with each other, It was probably as diverse as it is today.

“Plate tectonics makes our planet uniquely dynamic at the scale of the solar system,” he said. in a statement Emily Mixon, lead author of the study and researcher at the University of Wisconsin-Madison. “It has been hypothesized that because plate tectonics is important for moving carbon and water on long time scales, “could be important for the way life evolved on Earth.”

The movement of the continents is destructive: crustal rocks are destroyed and recycled. To reveal the ancient processes behind tectonics, researchers studied zircons, that are physically durable and resistant to chemical alterations.

More specifically, they studied zircons in the Saglek-Hebron complex, between 3,900 and 2,700 million years old, and in the Acasta Gneiss complex, between 4,000 and 3,400 million years old.

– both in Canada – and discovered that, instead of a linear progression of tectonic styles, from volcanic lavas and magmas pushing the crust into the mantle, followed by plates colliding with each other and pushing oceanic crust into the mantle, Many different styles coexisted, just as they do today.

“Understanding how tectonics worked early in Earth’s history is key to identifying when and how we got the styles of modern tectonics we see today, and what these styles might be expected to look like early in planetary development.” of other possible habitable planets“Mixon said.