Tasmania’s place in the prehistoric world seems to have become clearer with evidence that the island state was once snugly attached to western North America.



Research from the University of Tasmania found a close prehistoric connection between Tasmania and North America through the analysis of tiny minerals.



Analysis of monazite and zircon, found in rocks from the ancient Rocky Cape Group in north-west Tasmania, found that they are between 1.45 billion and 1.33 billion years old.

These minerals, researchers discovered, strongly resemble those found in Montana, Idaho and southern British Columbia. Fossils called Horodyskia, or “string of beads”, have also been found in both sites. At more than 1 billion years old, the fossils are some of the oldest visible to the naked eye.

This “strong genetic fingerprint” evidence suggests that the two groups of rocks were geographical neighbours 1.4 billion years ago.

At this time, parts of Australia and Antarctica were attached to North America in a supercontinent called Nuna, a mass of land which preceded the more well-known Gondwana formation.

However, Tasmania’s place in this mass has never been entirely clear. The matter is complicated by the fact that rocks in the state differ from the rest of Australia.

Previous theories suggested that Tasmania emerged from central Australia as the supercontinents broke apart, but the new evidence contradicts this.



“Tasmania hasn’t been placed anywhere on the map for this period, which is around 1.5 billion years ago,” said researcher Dr Jacqueline Halpin. “We can now say it was linked to an area of North America.



“The rocks of Tasmania don’t look like the rest of Australia’s rock if you look at those more than 700 million years old. The rocks up the east coast of Australia are much younger than in Tasmania. In terms of the geology, Tasmania is much more like North America.”

