The ancient continent of Argoland, which was once connected to Western Australia, has been discovered millions of years after it floated away.
Oceanic clues left behind by the 5000km “Gondwana-derived fragment” signalled its existence, but tracking it down took scientists in the Netherlands seven years.
WATCH THE VIDEO ABOVE: The ancient drift of the lost continent Argoland reconstructed from Western Australia to South-East Asia.
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A deep basin, known as the Argo Abyssal Plain, off the WA coast hinted that a large piece of land had shattered off Australia’s northwest and floated away 155 million years ago, according to a new report by scientists at Utrecht University, published in the scientific journal Gondwana Research.
Its whereabouts remained a mystery that, now solved, will provide valuable information on evolution, climate, biodiversity, tectonic forces and the formation of mountains, as well as the location of raw materials.
But discovering the lost continent has also helped to complete the larger puzzle of Gondwana.
Unlike Africa and South America, which broke away from the former super continent in two large pieces, the report found that Argoland broke into shards during the Jurassic period.
“We spent seven years putting the puzzle together,” Dr Eldert Advokaat, one of the research authors behind the discovery, said.
“Imagine that, we have an idea of something rifted off from Australia, we still have that scar preserved in the Argo Abyssal Plain, but we cannot find the fragments,” he told 7NEWS.com.au.
“Then we have a problem because … we cannot make reliable reconstructions of what Earth looked like in the deep geological past.”
As other ancient landmasses are known to have totally submerged in the Earth’s mantle, it wasn’t clear whether Argoland had also become completely swallowed beneath the sea, before the discovery.
And while some of it was subducted, much of Argoland is “now jumbled up in Southeast Asia”, where the “ribbons of continent” drifted northwest together as an archipelago, Advokaat said.
“The most northern and western pieces (of Argoland) are now below Western Myanmar, then we find them in Borneo, in Java, in Sulawesi, and in Timor.”
Over millions of years of geological movement, mountains were formed and then eroded, new oceans were formed and kilometres of sediment dumped on top of them — all of this leaving just “windows to these older rocks,” Advokaat said.
Geological imaging technology measured hidden lengths of the lost continent buried in the Earth’s mantle, and geologists tested the age of rock formations across South-East Asia to test their reconstructions.
They worked backwards to their discovery, “peeling back” the evidence of younger events “to arrive back, 200 million years ago,” Advokaat said.
At that point, 200 million years ago, Argoland had already been splintering for 75 million years, and would take another 45 million years before it would drift away.
The long, ancient journey was preserved within Argoland, which recorded the Earth’s magnetic field, including its direction and intensity, in its minerals and rocks as they were being formed.
“Scientifically, it was a big relief to have found it,” Advokaat said.
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