Geologists Find Evidence of Global Plate Tectonics 2 Billion Years Ago

Subduction assembled the Nuna supercontinent. (Image courtesy IGG)

(CN) — Think the first world wide web is a recent development? Think again. Billions of years before the internet was created, a natural process involving tectonic plates became a global network that transformed our world.

A new study from the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences found that plate tectonics involving subduction — the pushing of one continental plate beneath another when two plates converge — spread worldwide 2 billion years ago.

“It’s like the invention of the world wide web,” said co-author Dr. Ross Mitchell of IGG. “Even though the internet existed in some form or another for decades, it wasn’t until the 1990s that the Information Age began.”

The same can now be said of plate tectonics, according to the study, which was published in the journal Science Advances.

Earth is divided into massive slabs of rock called tectonic plates that scrape past each other in a process known as continental drift. Typically, ocean crust dips beneath continents when those plates interact, pushing the dense crust deeper into the Earth’s core. When two continents collide, however, the force of the land masses pushes rocks upward, forming mountains. The most stunning example of this activity is the Himalaya mountain range, which was created when the land mass now called India slammed into Eurasia billions of years ago.

In the past, geologists have found evidence of continental drift, including lingering magnetism in rocks indicating changes in latitude relative to Earth’s magnetic poles. But for the first 2.5 billion years of Earth’s history, this geological activity is believed to be limited to certain parts of the globe.

Now a research team led by Dr. Bo Wan of IGG has found evidence of ancient subduction in China that indicates when plate tectonics spread across the planet and began forming geological features that make up our modern world.

Using a seismological study, researchers examined the structure of ancient crust in the Ordos Plateau of Inner Mongolia, a flat region with no tall mountains. To their surprise, they discovered the same deep geological structure that exists in the Himalayas.

“Even though the dipping structure we found was identical to what we see in the Himalaya today, what we were looking at was 2 billion years old,” Wan stated.

But clues of ancient subduction in China were not all researchers found. Building on their discovery, they began examining other continents and discovered similar dipping structures that occurred at roughly the same time, linking six land masses in a colossal plate network that created what was likely Earth’s first supercontinent. Called Columbia or Nuna, the giant land mass measured 8,000 miles from north to south at its broadest part before it began fragmenting about 1.5 billion years ago.

“Immediately following plate tectonics going global, Earth formed arguably its first supercontinent,” said Dr. Mitchell. “This coincidence is too compelling to ignore.”

The study’s seismic findings of subduction on these six continents is the oldest known evidence of global plate tectonics.

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