We all learned back in geography class that what we see as present-day continents were once a big mashup of land that broke off into different chunks, collided with others, and eventually formed the world as we know it. Still, there are some quirks about continental drift that we’re still learning, and new research from scientists in Australia has revealed that a big chunk of land on their home continent actually originated in what would become Canada.
The research, which was published in the Geology, began when the team realized that some of the sandstone rocks that make up an area of northern Queensland didn’t seem to belong there. The rock was so different from what they were used to seeing that they decided to seek out its origins and were taken back in time 1.7 billion years.
The scientists believe that the large rock mass was originally attached to the North American continent some 1.7 billion years ago, well before the most recent super continent collision that created Pangea a few hundred million years ago. That older supercontinent is known as Nuna, and when the North American chunk met up with what would become Australia, the large land mass broke off from its home and collided with Australia.
“This was a critical part of global continental reorganization when almost all continents on Earth assembled to form the supercontinent called Nuna,” Curtin University PhD student Adam Nordsvan explains. “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. Georgetown then broke away from North America and collided with the Mount Isa region of northern Australia around 100 million years later.”
The discovery is not only important in the greater understanding of Australia’s geological history, but could also help paint a clearer picture of what the Earth looked like between 1.7 billion and 1.6 billion years ago. The research team believes that when the land mass collided with Australia it was relatively gentle, and while it would likely have created mountainous terrain over time, it wasn’t a violent event like the one between India and Asia that created the Himalayas.