Plate tectonics evolved earlier than previously thought, research suggests

The Earth and its continents may have been shifting for longer than scientists previously thought.

A new study of rocks formed billions of years ago suggests plate tectonics evolved over the last 2.5 billion years.

This is contrary to previous studies that said it emerged only 700 million years ago.

The new timeline impacts researchers’ models for understanding how the Earth has changed.

Plate tectonics dictates how continents drift apart and come back together, says the study published in the Nature journal.

It helps to explain where volcanoes and earthquakes occur, predict cycles of erosion and ocean circulation, and how life on Earth has evolved.

First author Robert Holder, at Johns Hopkins University in Maryland, said: “One of the key ways to understand how Earth has evolved to become the planet that we know is plate tectonics.”

The team examined a global compilation of metamorphic rocks that formed over the past three billion years at 564 sites.

Metamorphic rocks have transformed into a new type of rock through the process of being buried and heated deep in the Earth’s crust.

Because plate tectonics strongly influences heat flow, ancient metamorphic rocks can be used to study plate tectonics in Earth’s past.

Researchers compiled data on the temperatures and depths at which the metamorphic rocks formed and then evaluated how these conditions have changed systematically through geological time.

From this, the team found that plate tectonics, as we see it today, developed gradually over the last 2.5 billion years.

Dr Holder said: “The framework for much of our understanding of the world and its geological processes relies on plate tectonics.

“Knowing when plate tectonics began and how it changed impacts that framework.”

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