A brand new ocean-mapping expedition is drawing the boundaries of Zealandia, a submerged “lost continent” that hosts New Zealand and the territory of New Caledonia in the South Pacific.
Zealandia broke off from the supercontinent Gondwana between 79 million and 83 million years in the past. Except for New Zealand and New Caledonia, this fragment of continental crust now sits on the ocean ground. It’s not the one bit of continental crust that is indifferent from a bigger continent, however it’s the largest at 1.9 million sq. miles (4.9 million sq. kilometers). That’s six instances bigger than the next-largest continental fragment, the microcontinent of Madagascar.
Zealandia, also called Te Riu-a-Māui in Māori, was assigned continental standing in 2017. Since then, researchers have been working to map the lost continent — no simple feat, as 94% of it’s beneath water.
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Now, Derya Gürer, an earth scientist on the University of Queensland in Australia, and her colleagues have collected new knowledge on the northwestern edge of Zealandia, which is situated offshore in Queensland’s Coral Sea Marine Park. The researchers spent 28 days aboard the vessel Falkor exploring the area, mapping 14,285 sq. miles (37,000 sq. km).
“Our expedition collected seafloor topographic and magnetic data to gain a better understanding of how the narrow connection between the Tasman and Coral Seas in the Cato Trough region — the narrow corridor between Australia and Zealandia — was formed,” Gürer mentioned in a college assertion.
The space between the Australia plate and the Zealandia plate is probably going very difficult, Gürer mentioned. There are in all probability a number of microcontinents submerged there, all of which splintered off the primary continental lots when Australia broke free of Gondwana. (The supercontinent encompassed what’s in the present day South America, Africa, Antarctica, Australia, Zealandia, Arabia and the Indian subcontinent.) These fragments of continental crust are completely different from the encompassing oceanic crust of the seafloor, which is denser and thinner than continental crust.
Done in collaboration with the Schmidt Ocean Institute, the mapping was half of the Seafloor to Seabirds expedition. The mapping knowledge can even feed into a bigger undertaking, the Seabed 2030 collaboration, which goals to make a publicly obtainable, complete map of the ocean ground by 2030. According to the National Oceanic and Atmospheric Administration (NOAA), lower than 10% of the seafloor has been mapped by trendy sonar strategies, which use sound to disclose undersea topography. The Seafloor to Seabird expedition not solely collected details about topography, but in addition knowledge on the depth of the magnetic area throughout the world. Because oceanic crust and continental crust are made of completely different mineral concentrations with completely different magnetic signatures, this knowledge will allow researchers to reconstruct the damaged fragments of Gondwana.
“The seafloor is full of clues for understanding the complex geologic history of both the Australian and Zealandian continental plates,” Gürer mentioned.
Originally revealed on Live Science.