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The continents on our planet are not stationary; Because of plate tectonics (a scientific geological theory that explains the movements that occur in the Earth's outer crust), over millions of years, they can join together to form "supercontinents" and break apart to form smaller continents. Scientists are now finding evidence of a lost continent that has moved away from the land mass that became Australia 155 million years ago. Geologists have long speculated that Argoland is one of these microcontinents, but there has been little evidence of where it has gone.
A team from Utrecht University in the Netherlands reconstructed the history of Argoland, finding that the 5,000-kilometer-long plot of land (more than the width of North America) "migrated" to South Asia and now sits more than 18,000 feet (5.5 km) below the surface of the Indian Ocean. The structure of the seabed in the Argo Abyss Plain, the deep ocean basin left behind by the Argoland disengagement, indicates that the continent was swept northwest, and probably reached somewhere in what are now the islands of Southeast Asia (Malaysia, Singapore, Indonesia, the Philippines, Brunei and East Timor).
According to the researchers, there is no huge continent hiding beneath these islands - only small continental fragments, so they turned to geological analysis of Southeast Asia to find clues about the fate of Argoland.
By reconstructing models and fieldwork data from several islands, including Sumatra, Borneo and the Andaman Islands, they discovered that Argueland was never a single, coherent continent. It began splitting into pieces about 300 million years ago, forming what researchers called an ergoflagella.
"The situation in Southeast Asia is very different from places like Africa and South America, where a continent has broken neatly into two pieces. Argoland has split into many different pieces," Aldret Adbukat, one of the study's authors, explained in a statement. These fragments are now hidden beneath large parts of Indonesia and Myanmar (Burma), having arrived there around the same time.
The researchers also found that the decomposition of Argoland accelerated about 215 million years ago, which explains why the "continent" became so fragmented and why it made putting all the pieces together much more difficult for the team. "We were really dealing with islands of information, which is why our research took so long. We spent seven years putting the puzzle together," Advocaat said.
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From the study: Finding Argoland: Microcontinental Archipelago Reconstruction"/official website, Utrecht University
It may have taken them a long time, but as study author Duo van Hinsbergen explained, it's important to know how lost continents became so. "These reconstructions are essential for understanding processes such as the evolution of biodiversity and climate, or for finding raw materials. Also at a more basic level: understanding how mountains form or understanding the driving forces behind plate tectonics – two closely related phenomena."
Argoland isn't the only "lost" continent that was eventually found – just recently, the mythical continent of Zealandia turned out to be real after all, and about four years ago, the lost continent of Balcantolia, which existed about 40 million years ago, was home to exotic animals and may have paved the way for Asian mammals to parts of continental Europe.
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