Published: Tue, January 23, 2018
Research | By Jody Lindsey

Evidence suggests that part of Australia used to be connected to Canada

Evidence suggests that part of Australia used to be connected to Canada

Scientists recently discovered a region of Australia that was once part of North America, bolstering support for the idea that the two existed as a unified "supercontinent" almost two billion years ago. When geologists analyzed and matched the rocks of two different regions, Australia and North America, they found out that a part of Australia was once attached to North America nearly 1.7 billion years ago.

Georgetown area while still attached to North America (left). While the scientific community believed that the landmass under northeast Australia had once been situated by North America, northern China or Siberia, there was never sufficient geological data to prove it.

Instead, they show similarities to ancient rocks found in Canada, in the exposed section of the continental crust called the Canadian Shield. They believe that the piece broke away from the continent some 1.7bn years ago and collided with Northern Australia's Mount Isa region.

Found in Georgetown, a small town of just a few hundred people in the north east of Australia, the rocks are unlike other rocks on the Australian continent.

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Geologists tend to agree that, billions of years ago, the configuration of the continents was very different. Adam Nordsvan, a Curtin University doctoral student and lead author of the study, claims that some 300 million years after the event that separated Georgetown from North America, the supercontinent of Nuna disassembled into various landmasses. During this period, nearly all continents on Earth grouped together and formed an ancient supercontinent called Nuna, aka the Columbia supercontinent. Although scientists are still piecing together the jigsaw-puzzle pieces, they have good hints that another supercontinent called Nuna, sometimes known as Columbia, existed prior to Pangaea.

The team reached its conclusion by examining new sedimentological field data, and new and existing geochronological data from both Georgetown and Mount Isa, another remote town in north east Australia, and comparing it to rocks from Canada. For instance, when the continental plates of India and Asia merged 55 million years ago, it resulted in the formation of the Himalayas.

Research paper co-author Professor Zheng-Xiang Li said the research also revealed new evidence of mountains being built in both the Georgetown region and Mt Isa when Georgetown collided with the rest of Australia, but that the collision was not hard. A recent study suggests new information regarding Australia's history, indicating that a small area of the country was once part of Canada - forming a supercontinent named Nuna. He further said that their latest finding is a key step in understanding how Nuna, Earth's first Supercontinent might have formed.

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