The lost continent of Argoland was discovered in the jungles of Southeast Asia

Researchers have discovered evidence of a lost continent hidden beneath jungles in Southeast Asia, according to a study.

Geoscientists have long suspected that around 155 million years ago, a long piece of continent broke off from northwest Australia and drifted away. The proof of this is the “void” it left behind – a basin known as the Argo Abyssal Plain that lies deep beneath the ocean off the coast of northwest Australia.

The structure of the seafloor indicates that the proposed continent – called Argoland after the deep-sea plain – must have drifted northwest and ended up where the islands of Southeast Asia are today.

A map showing the history of Argoland
A map shows the history of the “lost” continent of Argoland. Geologists from Utrecht University have reconstructed the history of Argoland and found that it exists in fragments in a region of Southeast Asia.
Utrecht University

The proposed continent of Argoland stretched more than 3,000 miles from Western Australia to north of Papua New Guinea. Researchers expected to find a solid continent hidden beneath the islands of Southeast Asia, but no such large continent was found in the region, only small fragments.

It has been suggested that these fragments belonged to Argoland, but they are only a fraction of the size of the proposed continent. In addition, the fragments are surrounded by remnants of oceanic basins that are about 205 million years old – much older than the rock record in the oceanic crust of the Argo-Abyssal Plain. This suggests that the fragments drifted away from Australia significantly earlier than Argoland’s proposed split around 155 million years ago.

These older ages had cast doubt on whether these fragments represented parts of Argoland. If not, the question arose: Did Argoland then disappear completely through a process known as subduction? This is when a tectonic plate slides under another plate and sinks into the Earth’s mantle, the geological layer that lies directly beneath the Earth’s crust.

To find out, geologists Douwe van Hinsbergen and his colleague Eldert Advokaat from the University of Utrecht in the Netherlands have now reconstructed the history of the lost continent for a study published in the journal Gondwana research.

said Newsweek: “Our motivation for conducting this research was to figure out how to reconcile this information: why are the fragments smaller, how did we lose such an area of ​​continental crust without leaving a trace, and why do these fragments appear to be smaller? to have disappeared earlier. “What do we know from the records in Australia?”

If Argoland actually disappears through subduction, it would be “bad news” because it would pose a major scientific problem, according to the two geologists. This would suggest that researchers may have missed entire “lost” continents that were simply buried in the Earth’s mantle.

In a press release, Van Hinsbergen said: “If continents can plunge into the Earth’s mantle and disappear completely without leaving a geological trace on the Earth’s surface, then we would not have much of an idea of ​​what the Earth might have looked like in its geological past. It would be nearly impossible to produce reliable reconstructions of former supercontinents and Earth’s geography in past eras.

He continued: “These reconstructions are crucial for our understanding of processes such as the evolution of biodiversity and climate or the search for raw materials. And on a more fundamental level, to understand how mountains form, or to find out the driving forces behind them. Plate tectonics, two phenomena that are closely linked.

However, in the latest study, geoscientists found that Argoland is still present, albeit in a fragmented form.

The Earth from space
The location of the lost continent of Argoland can be seen in the lower right quadrant of the globe’s visible surface.

For the study, Advokaat and Van Hinsbergen used software that allowed them to reconstruct the movement of tectonic plates over hundreds of millions of years.

This work revealed that the proposed continent of Argoland was not a solid block when it separated from Australia about 155 million years ago. Instead, at this point it appears to have already broken up into a kind of “archipelago” made up of several small continents and ocean basins in between.

This process is similar to the history of other “lost” continents such as Zealandia off the coast of eastern Australia and Greater Adria in the Mediterranean.

“The breakup of Argoland into the ‘Argopelago’ was a process that began more than 200 million years ago,” said the two geologists Newsweek.

The continental fragments that once formed Argoland are now located in Myanmar and on the islands of Java, Sulawesi, Borneo and Timor. All of these islands are at least partially governed by Indonesia. In the case of Borneo, parts of the territory also belong to Malaysia and Brunei. Timor, meanwhile, is divided between Indonesia and the sovereign state of East Timor. The geologists also conducted field research on several islands to test the models in their study.

“The most important conclusion of this research is that we have not lost the continental crust without a trace,” said the two researchers. “Instead, a large part of Argoland consisted of oceanic crust, the remnants of which we also found in Southeast Asia. This study therefore helps our understanding of processes on Earth such as subduction.”

It continues: “Above all, it shows that … our reconstructions of Earth’s geography in the past do not miss any major ‘lost’ continents. We may have to search a little, but the remains are still there in the geological record.” “