"Finding Argo land proved challenging," geologists wrote in a pre-print study posted Oct. 19 in the journal Gondwana Research.
"We spent seven years putting the puzzle together," Elder Advocaat, one of the study authors, said in a university news release.
Argo land is believed to have broken off from Australia during the late Jurassic period, when Stegosauruses roamed the Earth. Over the millennia, it then drifted toward Southeast Asia before eventually disappearing.
Researchers have long suspected the continent once existed, as evidenced by a "void" or basin it left behind, known as the Argo Abyssal Plain. But no remnants of such a land mass had ever been found.
"If continents can dive into the mantle and disappear entirely, without leaving a geological trace at the earth's surface, then we wouldn't have much of an idea of what the earth could have looked in the geological past," Douse van Ginsberg one of the study's authors, said in the release.
But finally, the continent's rocky crumbs have been spotted. Dutch geologists detected traces of the lost land mass in the form of tectonic "mega-units," which are scattered on the ocean floor and embedded within small islands.
Parts of the continent, which once extended over 3,000 miles, were "hidden beneath the green jungles of large parts of Indonesia and Myanmar," researchers said.
Using these remains, geologists were able to meticulously map out Argo land's slow destruction, which they then recreated in a video.
It appears to have fractured into an archipelago during the Late Triassic period, parts of which later plunged into the sea, researchers said.
Other lost continents underwent similar processes, including Zealandia, a submerged mass near Australia, and Greater Adrian, a continent once located in the Mediterranean Sea.
Piecing together the life and death of continents is "vital for our understanding of processes like the evolution of biodiversity and climate, or for finding raw materials," van Hinsbergen said in the release. "And at a more fundamental level: for understanding how mountains are formed or for working out the driving forces behind plate tectonics. "Based on the marine magnetic anomalies identified in the Argo Abyssal Plain offshore northwestern Australia, the conceptual continent of Argo land must have rifted off in the Late Jurassic (∼155 Ma) and drifted northward towards SE Asia. Intriguingly, in SE Asia there are no intact relics of a major continent such as India, but instead the region displays an intensely deformed, long-lived accretionary orogeny that formed during more than 100 million years of oceanic and continental subduction. Within this orogeny, there are continental fragments that may represent parts of Argo land. After accretion of these fragments, the orogeny was further deformed. We compiled the orogenic architecture and the history of post-accretionary deformation of SE Asia, as well as the architecture and history of the NW Australian passive margin. We identified the Gondwana-derived blocks and mega-units of SW Borneo, Greater Paternoster, East Java, South Sulawesi, West Burma, and Mount Victoria Land as fragments that collectively may represent fragments of Argo land. These fragments are found between sutures with relics of Late Triassic to Middle Jurassic oceanic basins that all pre-date the break-up of Argo land. We systematically restore deformation within SE Asia in the upper plate system above the modern Sundae trench, use this to estimate where Gondwana-derived continental fragments accreted at the Sunderland (Eurasian) margin in the Cretaceous (∼110–85 Ma), and subsequently reconstruct their tectonic transport back to the Australian-Greater Indian margin. Our reconstruction shows that Argo land originated at the northern Australian margin between the Bird’s Head in the east and Wallaby-Zenith Fracture Zone in the west, south of which it bordered Greater India.
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