‘Lost continent’ of Argolândia is found – 11/10/2023 – Science

One of geology’s biggest unknowns has now been resolved: geologists from Utrecht University in the Netherlands have announced that they have managed to find the “lost continent” of Argoland, which was formed 155 million years ago and then disappeared.

It was a huge piece of land, around 5,000 km long, that separated from western Australia, when the country was part — along with South America, Africa, India and Antarctica — of the ancient supercontinent of Gondwana.

Scientists have known about the existence of Argoland for a long time because they found traces of its separation from Australia.

In addition to fossils, mountain ranges and rocks (where there are often traces of continental divisions), the clearest evidence was the huge hole left by the part that broke apart: a basin located deep in the ocean, west of Australia, called the Abyssal Plain of Argo (hence the name with which the disappeared continent was baptized).

Although it is easy to understand how the separation of other continents that were previously united in Gondwana occurred — for example, if you look at Africa and South America you see that they would fit together perfectly — Argoland was not visible. Scientists then looked for the huge piece of land that would “fit” the coast of Australia.

Dutch geologists, led by Eldert Advokaat, solved the mystery: there is no longer a large land mass called Argoland because this continent, after separating, fragmented, becoming an archipelago.

Part of it sank and is now under Southeast Asia, in the form of oceanic plates. But there are also chunks of this elusive continent “underneath the green jungles of much of Indonesia and Myanmar,” according to research published in the scientific journal Gondwana Research.

How the continent was found

The team of scientists tested different computer models for seven years to find the location of Argolândia.

“We were literally dealing with islands of information, which is why our research took so long,” Advokaat explained in a press release.

“Argoland was divided into many different fragments. This obstructed our view of the continent’s travel.”

After realizing that Argoland had not been preserved as a single landmass, but rather transformed into a series of microcontinents separated by the ocean, Advokaat and his fellow geologist at Utrecht University, Douwe van Hinsbergen, began the arduous task of identifying each sector.

They also coined a new name that more accurately defines the continent’s current geology: “argopelago.”

Wallace’s Line

Putting together the puzzle of this lost continent could also help explain another mystery that intrigues scientists — biologists, in this case.

It’s the so-called “Wallace line”, an invisible barrier that separates the fauna of Southeast Asia from the fauna of Australia.

Biologists noticed that the animals on both sides of this line, which crosses the south of the Indonesian archipelago (a country made up of more than 10 thousand islands), are very different from each other and do not mix.

West of the line are placental mammals such as monkeys, tigers and elephants, which are almost completely absent to the east, where marsupials and cockatoos, animals typically associated with Australia, can be found.

“While the Malay Peninsula and the islands of Sumatra, Java and Borneo (in Indonesia) are home to ‘Eurasian’ animals, the island of Sulawesi (also known as Celebes) in Indonesia is home to ‘Australasian’ animals, a mix between Eurasian and Australian animals”, explained Advokaat to BBC Mundo.

“This mixing is explained by the fact that the ‘Eurasian’ western part of Sulawesi came into contact with the ‘Australian’ southeastern part of the island between 28 and 3.5 million years ago, as we show in our reconstruction,” he added.

According to the “discoverers” of Argoland, this may have happened because the continent took its own wildlife with it when it separated from Australia and joined Southeast Asia.

This curious division is not only seen in mammals and birds. Evidence was even found that the first human species that inhabited the islands of Southeast Asia also respected this invisible barrier.

“These reconstructions are vital for our understanding of processes such as the evolution of biodiversity and climate, or for finding raw materials,” highlighted van Hinsbergen.