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article imageNew evidence suggests Australia was once part of Canada

By Karen Graham     Jan 22, 2018 in Science
Georgetown - Geologists believe Columbia, also known as Nuna and Hudsonland, was one of Earth's ancient supercontinents, 2.5 to 1.5 billion years ago. Researchers now believe a remote part of Australia was once part of Canada, based on an interesting discovery.
Australian researchers found a series of rocks that show something quite surprising: part of Australia could have once been connected to a part of Canada on the North American continent, around 1.7 billion years ago.
The rocks were found in Georgetown, a small town of a few hundred people in Northeastern Queensland and have geological signatures that are unknown anywhere else in Australia, but they are similar to rocks found in Canada's Precambrian shield.
Needless to say, this unexpected finding will reveal something about the composition of the ancient supercontinent, Numa, according to the researchers from Curtin University, Monash University and the Geological Survey of Queensland in Australia.
A 2008 Mercator projection of the Earth. Source image is from NASA s Earth Observatory  Blue Marble ...
A 2008 Mercator projection of the Earth. Source image is from NASA's Earth Observatory "Blue Marble" series. This is the only continent layout anyone has ever known.
"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," says lead scientist Adam Nordsvan, a Ph.D. student from Australia's Curtin University.
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Nordsvan went on to explain: "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."
The ancient supercontinent, Numa
Keep in mind that most geologists believe in the existence of Numa, based on extensive research published in 2002 by John J.W. Rogers and M. Santosh. In the 2002 study, the researchers point out there may have been two ancient supercontinents that formed well before Pangea.
The suggested configeration of the supercontinent Columbia by the author of the study John J.W. Roge...
The suggested configeration of the supercontinent Columbia by the author of the study,John J.W. Rogers.
John J. W. Rogers
Rogers was quoted as saying: "I named the supercontinent Columbia because some of the best evidence for its existence is in the Columbia River region of western North America, Starting at about 1.8 billion years ago, all of the continents existing at that time began to collide into a single land area."
"This formed an area that stretched about 8,000 miles from southern South America to northern Canada and was about 3,000 miles across at its widest part," Rogers said.
Pangea formed after the breakup of the supercontinent Rodinia about 750–633 million years ago. And of course, Rodinia was formed after the breakup of the supercontinent, Columbia, or as it is known, Numa about 1.5 billion years ago. Here is what's so interesting — little is known about the Earth's paleogeography before the formation of Rodinia.
Canada s Shield is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geo...
Canada's Shield is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geological shield) that forms the ancient geological core of the North American continent. This image is of the Flin Flon, Manitoba region.
Green Slash
It has been assumed that paleomagnetic and geologic data are only definite enough to form reconstructions from the breakup of Rodinia. We do know that unlike later supercontinents, Rodinia would have been entirely barren. Rodinia existed before complex life colonized dry land. And while ultraviolet light discouraged organisms from living on Rodinia's surface, there were marine organisms.
One conclusion drawn from the study is a shocker - The researchers believe that when Numa broke apart an estimated 300 million years later, the Georgetown area remained permanently stuck to the rest of Australia. This goes against everything we have come to know about the Australian continent.
This very interesting study was published in the journal Geology on January 17, 2018. The title is "Laurentian crust in northeast Australia: Implications for the assembly of the supercontinent Nuna"
More about Canada, Queensland Australia, Geology, Science, supercontinent
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