Australia Was Part of North America Supercontinent Over 1 Billion Years Ago, New Study Shows
It's easy to forget that the world's continents have been sliding around Earth's surface, colliding and ripping apart, for the last few million years. The collision of India and Asia, for example, formed the Himalayas. And according to new research, a relatively small region of Australia was once part of Canada when the world's landmasses were gathered in a supercontinent dubbed Nuna.
Researchers at Curtin University, Monash University and the Geological Survey of Queensland in Australia came together to study some interesting geology around the small town of Georgetown, whose rocks bore a strong resemblance to those found in ancient Canada. According to lead researcher Adam Nordsvan:
"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. This was a critical part of global continental reorganisation when almost all continents on Earth assembled to form the supercontinent called Nuna."
Just about everyone has heard of the ancient supercontinent of Pangea, which fractured about 175 million years ago, but few have heard of Nuna (also known as Columbia), which formed 1.5-2.5 billion years ago. According to Space Daily:
"Columbia is estimated to have been approximately 12,900 km (8,000 mi) from North to South at its broadest part. The eastern coast of India was attached to western North America, with southern Australia against western Canada. In this era most of South America was rotated such that the western edge of modern-day Brazil lined up with eastern North America, forming a continental margin that extended into the southern edge of Scandinavia."
Here's a short video that explains a bit more about Nuna/Columbia.
Much of Nuna's history is still a mystery, but this discovery in Georgetown offers a clue to how one of the world's first supercontinents formed and broke apart.