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Tasmania’s North American Ancestry

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Antarctica was once linked to North America, with Tasmania tightly sandwiched between the two land masses and a considerable distance from what is now mainland Australia, according to research published in Geology.

The new findings build on a link between sedimentary rocks found in north-west Tasmania and the Belt–Purcell Supergroup in Montana, Idaho and southern British Columbia, which indicated that Tasmania and North America were geographically very close when they formed part of the Nuna supercontinent 1.4 billion years ago.

“While this new research corroborates the link between Tasmania and North America, it goes further by providing strong evidence that Antarctica was also part of that chain, with Tasmania relatively closely squeezed in between,” said PhD student Jacob Mulder of The University of Tasmania.

“Importantly, it also indicates that Tasmania was situated a substantial distance away from the land masses that later formed modern-day Australia.”

Mulder and co-workers determined the age and isotopic composition of zircon from the Rocky Cape Group in Tasmania’s north-west, and compared this with the age and isotopic composition of zircons from potential source rocks around the globe.

By using zircon to fingerprint the source rocks that eroded to form the Rocky Cape Group, the researchers were able to position Tasmania within...

The full text of this article can be purchased from Informit.