Scientists have found evidence of a lost continent that drifted away from the land mass that became Australia 155 million years ago.
Geologists long assumed that Argoland should exist due to a massive void in Western Australia, but until now, the evidence was only circumstantial.
A team at Utrecht University Reconstructed the history of Argoland, finding the 3,100-mile-long piece of land traveled to South Asia and now sits more than 18,000 feet below the surface of the Indian Ocean.
Magnetic and structural geological evidence along the local seafloor suggested that the giant fragment separated through the shifting of tectonic plates that make up the Earth’s crust before drifting north and west toward Southeast Asia.
Scientists have found evidence of a lost continent that drifted away from the land mass that became Australia 155 million years ago
By reconstructing the lost continent’s history, the team determined it drifted up to South Asia
Eldert Advokaat, with the Department of Earth Sciences at Utrecht University in the Netherlands, said: ‘The situation in Southeast Asia is very different from places like Africa and South America, where a continent broke neatly into two pieces. Argoland splintered into many different shards.
‘That obstructed our view of the continent’s journey.’
Researchers used a computer reconstruction based on existing geological evidence to paint a picture of how Argoland broke into multiple pieces, settling around modern-day Indonesia and Myanmar.
Rather than a single land mass, they found many smaller bits that pieced themselves together over millions of years.
By settling this mystery, geologists have filled in a significant knowledge gap, adding new context to the body of evidence on how mountains, islands and undersea geology took shape.
The theorized continent of Argoland broke off of Australia millions of years ago and migrated northwest, but until now, its final home was unknown.
Argoland’s existence was implied by a void in Western Australia called the Argo Abyssal Plain. The fragments of Argoland now reside in present-day Southeast Asia
By reviewing the architecture of known southeast Asian and northwest Australian tectonic ‘mega-units,’ the team pieced together scattered remnants of what once comprised Argoland and proposed how they drifted so far from home.
During the late Jurassic period, the massive landmass of Pangaea broke up into two supercontinents, Laurasia and Gondwana. The break was not a clean one, though.
At this time, it seems that Argoland was already split into multiple continental fragments and sections of the seafloor.
The islands of Argoland’s proposed destination do not seem to sit atop anything resembling the theoretical continent. The only bits of ancient continental crust in the region were much older, with radiologic dating placing them at about 205 million years old.
A team at Utrecht University reconstructed the history of Argoland, finding the 3,100-mile-long piece of land traveled to South Asia and now sits more than 18,000 feet below the surface of the Indian Ocean
One possibility was that the continent had slipped beneath a subduction zone and gotten recycled.
Subduction zones occur when one tectonic plate meets another and slips underneath its neighbor.
At these junctions, rocky seafloors will rejoin the mantle beneath the Earth’s crust, where they are melted back into magma to become crust at some point in the future.
Given the age mismatch between the Argo Abyssal Plain and these possible fragments, researchers suspected the fragments might not have come from Argoland.
They could have migrated there long before Argoland slipped beneath a subduction zone.
Based on the team’s reconstruction, over the millions of years between then and now, these fragments migrated across the Indian Ocean.
Though the geologists write that the fragments are ‘intensely deformed,’ they exist above ground in our current time.
They settled into areas now covered by jungle in Myanmar on mainland Asia and several islands in the Indonesian archipelago.
The researchers note some limitations of their reconstruction.
Many of the estimated geological ages of tectonic plate sections are based on old data, so they write modern measurements may prove more precise.
‘The dense vegetation cover and seas in the area we reconstructed complicated our correlations, and they may not always be correct,’ the researchers added.
