Geologists matching rocks from reverse sides of the globe have discovered that a part of Australia was as soon as hooked up to North America 1.7 billion years in the past.
Researchers from Curtin College in Australia examinedrocks from the Georgetown area of northern Queensland. The rocks — sandstone sedimentary rocks that shaped in a shallow sea — had signatures that had been unknownin Australia however strongly resembled rocks that may be seen in present-day Canada.
The researchers, who described their findings on-line Jan. 17 within the journal Geology, concluded that the Georgetown space broke away from North America 1.7 billion years in the past. Then, 100 million years later, this landmass collided with what’s now northern Australia, on the Mount Isa area. [Photo Timeline: How the Earth Formed]
“This was a essential a part of international continental reorganization when virtually all continents on Earth assembled to kind the supercontinent known as Nuna,” Adam Nordsvan, Curtin College doctoral scholar and lead writer of the examine, stated in a assertion.
Nordsvan added that Nuna then broke aside some 300 million years later, with the Georgetown space caught to Australia because the North American landmass drifted away.
The continents as we all know them as we speak have shifted locations all through Earth’s Four-billion-year historical past. Most just lately, these landmasses got here collectively to kind the supercontinent referred to as Pangaea about 300 million years in the past. Geologists are nonetheless attempting to reconstruct how even earlier supercontinents assembled and broke aside earlier than Pangaea. Scientists first proposed the existence of Nuna, Earth’s first supercontinent, in 2002. Nuna is typically known as Columbia.
Earlier analysis recommended that northeast Australia was close to North America, Siberia or North China when the continents got here collectively to kind Nuna, Nordsvan and colleagues famous, however scientists had but to seek out stable proof of this relationship.
Colliding landmasses can kind mountain ranges. For instance, the conflict of the continental plates of India and Asia about 55 million years in the past created the Himalayas. The researchers of the brand new examine say they discovered proof of mountains forming when Georgetown rammed into the remainder of Australia.
“Ongoing analysis by our workforce reveals that this mountain belt, in distinction to the Himalayas, wouldn’t have been very excessive, suggesting the ultimate continental assembling course of that led to the formation of the supercontinent Nuna was not a tough collision like India’s latest collision with Asia,”Zheng-Xiang Li, a co-author of the examine and a professor of Earth science at Curtin College, stated within the assertion.
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