The oldest minerals on Earth date the beginnings of plate tectonics 3.6 billion years ago

Plate tectonics enabled a connection between the chemical reactor inside the Earth and its surface, and this connection created the habitable planet humans currently enjoy, from oxygen in the atmosphere to concentrations of carbon dioxide. climate regulating carbon. But when and how the plate tectonics took off has remained a mystery, buried under billions of years of geological time.

The research team used zircons, the oldest minerals ever found on Earth, to look into the planet’s distant past. The team included Dustin Trail of the University of Rochester in New York, Jacob Buettner of the Los Alamos National Laboratory in New Mexico, and was led by geologist Michael Anderson of the Smithsonian National Museum of Natural History in Washington DC.

The zircons came from the Jack Hills in Australia and the oldest specimens were around 4.3 billion years old, meaning these nearly indestructible minerals were formed when the Earth itself was in its infancy and only around 200 million years old. years. Along with other ancient zircons from the Jack Hills that span Earth’s earliest history up to about 3 billion years ago, these minerals form the closest approximation scientists have to an unbroken chemical chronicle of the planet. nascent.

“We are reconstructing how the Earth went from a molten ball of rock and metal to what we have today,” Ackerson said. “None of the other planets have continents, liquid oceans, or life. In a sense, we are trying to answer the question of why Earth is unique, and to some extent we can answer it with these. zircons. ”