The 1.7-billion-year-old bedrock was found in Georgetown, a small town in northeastern Australia. But the rock has geological signatures that are unknown to Australia, researchers said in a study published in the journal Geology on Jan. 17.
The researchers believe the rock sediments look like it could be from the Canadian Shield.
This discovery suggests the Georgetown area was originally part of North America and formed a supercontinent called “Nuna,” the researchers said.
“Our research shows that about 1.7 billion years ago, Georgetown rocks were deposited into a shallow sea when the region was part of North America,” lead researcher, Adam Nordsvan, a PhD student from Australia’s Curtin University, said.
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“Georgetown then broke away from North America and collided with the Mount Isa region of northern Australia around 100 million years later. This was a critical part of global continental reorganization when almost all continents on Earth assembled to form the supercontinent called Nuna.”
These landmasses have shifted numerous times, specifically 300 million years ago to form the supercontinent, Pangea. However, now scientists are saying Nuna was the first supercontinent.
Scientists first proposed the existence of Nuna in 2002, also called Columbia.
“This new finding is a key step in understanding how Earth’s first supercontinent Nuna may have formed,” Nordsvan said.