A new ocean mapping mission delineates the borders of Zealandia, the “lost continent” underwater that hosts New Zealand and New Caledonia in the South Pacific Ocean. Zealandia separated from the supercontinent Gondwana between 79 million years and 83 million, and with the exception of New Zealand and New Caledonia, this piece is located from Continental crust is now on the ocean floor.
According to RT, it is not the only part of the continental crust separated from a larger continent, but the largest area is 1.9 million square miles (4.9 million square kilometers), which is six times larger than the second largest part of the continental part, the small continent of Madagascar.
Zealandia was granted continental status in 2017, and since then, researchers have been working to map the lost continent, which is not easy, as 94% of it is underwater.
Derya Gower, an earth scientist at the University of Queensland in Australia, and her colleagues collected new data on the northwestern edge of Zealandia, which is located offshore in Coral Sea Marine Park in Queensland.
The researchers spent 28 days aboard the Falkor exploring the area, mapping 14,285 square miles (37,000 square kilometers).
“Our mission gathered topographic and magnetic data for the sea floor to gain a better understanding of how the narrow connection between the Tasman Sea and the Coral Sea is formed in the Cato Truff region, the narrow corridor between Australia and Zealandia,” said Goerer in a statement to the university.
She explained that the area between the Australian Plate and the Zealandia Plate, is likely very complex.
It is possible that there will be many smaller continents submerged there, all of which separated from the main continental masses when Australia was liberated from Gondwana. (The supercontinent includes what is today South America, Africa, Antarctica, Australia, Zeelandia, Arabia, and the Indian subcontinent).
These parts of the continental crust differ from the oceanic crust surrounding the sea floor, and are denser and thinner than the continental crust.
The mapping was carried out in cooperation with the Schmidt Institute for the Oceans and was part of the Seabird expedition. The mapping data will also feed into a larger project, the Seabed 2030 Collaboration, which aims to provide a comprehensive map of the ocean floor by 2030.
According to the National Oceanic and Atmospheric Administration (NOAA), less than 10% of the mapping of the sea floor has been done using modern sonar methods, which use sound to reveal the topography of the sea floor.
The Seafloor mission to Seabird not only gathered information about the terrain, but also collected data on the strength of the magnetic field across the area. Since the oceanic crust and continental crust are composed of different concentrations of minerals with different magnetic signatures, this data will enable researchers to reconstruct the fractured portions of Gondwana.
“The sea floor is full of clues to understand the complex geological history of the Australian and Zeeland continental plates,” said Gower.