Australian town sitting on ancient part of North America

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A tiny town in Australia is actually sitting on a 1.7 billion-year-old chunk of North America, according to new research.

Scientists found that ancient rocks in the area around Georgetown, 250 miles (400km) west of Cairns, Queensland, were unlike any other rocks in Australia.

Instead, they were surprisingly similar to deposits found in Canada today, suggesting the two countries were once stuck together.

Australia and North America were once fused as part of of the supercontinent Nuna,  separating when the landmass broke up 1.6 billion years ago.

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Australia and North America were once fused as part of of the supercontinent Nuna, separating when the landmass broke up 1.6 billion years ago (right). This means that the small settlement of Georgetown, Australia, was actually once part of North America (left)

Australia and North America were once fused as part of of the supercontinent Nuna, separating when the landmass broke up 1.6 billion years ago (right). This means that the small settlement of Georgetown, Australia, was actually once part of North America (left)

HOW IT HAPPENED 

Billions of years ago, our planet looked very different.

Earth’s landmasses have repeatedly created and destroyed supercontinents over the course of the planet’s history as part of what experts call its ‘supercontinent cycle’.

A new study suggests that a chunk of northern Australia was actually part of what is now North America when the supercontinent Nuna formed 1.7 billion years ago.

When the huge landmass split apart 100 million years later, a small area of what is now Queensland, Australia broke off of Northern America.

Earth’s landmasses have repeatedly created and destroyed supercontinents over the course of the planet’s history as part of what experts call the ‘supercontinent cycle’.

Now a study from experts at Curtin University in Perth suggests Georgetown became a part of Australia when it collided with the landmass during the formation of Nuna, which began around 1.7 billion years ago.

When Nuna, also known as Columbia, naturally drifted apart 100 million years later, Georgetown and a chunk of northern Queensland broke off and stuck to Australia, the researchers said.

The Perth team compared sediment readings from both Georgetown and nearby Mount Isa as part of their study.

Study lead author Adam Nordsvan said: ‘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.’

Since the 1960s, researchers have proposed that Australia and North America were connected as part of Nuna, but the new study provides conclusive evidence that the two were once paired. 

Scientists found that rocks in the area around Georgetown, Queensland, were unlike any other deposits in Australia. Instead, they were similar to deposits found in Canada today, suggesting the town - with a population of roughly 250 - was originally a part of North America (stock)

Scientists found that rocks in the area around Georgetown, Queensland, were unlike any other deposits in Australia. Instead, they were similar to deposits found in Canada today, suggesting the town - with a population of roughly 250 - was originally a part of North America (stock)

Scientists found that rocks in the area around Georgetown, Queensland, were unlike any other deposits in Australia. Instead, they were similar to deposits found in Canada today, suggesting the town – with a population of roughly 250 – was originally a part of North America (stock)

Georgetown broke off from North America and became a part of Australia during the formation of a supercontinent 1.7 billion years ago, researchers said 

Georgetown broke off from North America and became a part of Australia during the formation of a supercontinent 1.7 billion years ago, researchers said 

Georgetown broke off from North America and became a part of Australia during the formation of a supercontinent 1.7 billion years ago, researchers said 

Researchers found that when the supercontinent Nuna broke apart the rock on which Georgetown sits did not drift away and instead became a new piece of Australia

Researchers found that when the supercontinent Nuna broke apart the rock on which Georgetown sits did not drift away and instead became a new piece of Australia

Researchers found that when the supercontinent Nuna broke apart the rock on which Georgetown sits did not drift away and instead became a new piece of Australia

The team found that when the supercontinent Nuna broke apart, the rock on which Georgetown sits did not drift away and instead became a new piece of Australia.

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.

‘Ongoing research by our team shows that this mountain belt, in contrast to the Himalayas, would not have been very high, suggesting the final continental assembling process that led to the formation of the supercontinent Nuna was not a hard collision like India’s recent collision with Asia,’ Professor Li said.

‘This new finding is a key step in understanding how Earth’s first supercontinent Nuna may have formed, a subject still being pursued by our multidisciplinary team here at Curtin University.’





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