Approximately 3,500 feet (1,000 meters) below the Pacific Ocean, off the coast of Australia, lies Zealandia, the eighth lost continent that has fascinated scientists since it was identified in 2017.
Now, New Zealand researchers were able to map the submerged land mass in stunning detail, offering a more accurate picture of the submerged continent than we’ve ever seen.
GNS Science researchers mapped the shape and size of the continent in unprecedented detail, making the maps available to everyone on an interactive website. They mapped the bathymetry surrounding Zealandia, the shape and depth of the ocean floor, as well as its tectonic profile, illustrating where the continent falls through the boundaries of tectonic plates.
The maps revealed new information about how Zealandia formed before it submerged underwater millions of years ago. The area covers an area of about two million square miles (five million square kilometers), which is half the size of Australia. But only 6% is above sea level, which supports northern New Zealand, and the rest is underwater.
“We have made these maps to provide an accurate, complete, and up-to-date picture of the geology of the New Zealand and Southwest Pacific area, better than we have ever had before,” maps lead author, geologist Nick Mortimer, said in a release. “Their value is that they provide a fresh context in which to explain and understand the configuration of New Zealand’s volcanoes, plate boundaries, and sedimentary basins.”
Mortimer and his team mapped both Zealandia and the submerged continent to raise awareness, but also to better understand the continent. The bathymetric map (below) shows how high the mountains and the crest of the continent rise to the surface of the water. It also shows the coasts, the territorial limits and the names of the main underwater features. The map is part of an initiative to map the entire ocean floor of the planet by 2030.
A second map made by the team (below) shows the types of crust that make up Zealandia, the age of the crust, and the main faults. The continental crust, which is the oldest and thickest crust on Earth, can be seen on the map in red, orange, yellow, and brown. Meanwhile, the oceanic crust can be seen in blue. Volcanoes are illustrated with red triangles.
A newly discovered continent
Geophysicist Bruce Luyendyk devised the nickname Zealandia in 1995. Speaking to Business Insider, he said he had no intention of describing a new continent. Instead, the term originally referred to New Zealand and a group of pieces of submerged bark that separated from the ancient Gondwana supercontinent about 85 million years ago.
“The reason I came up with this term is for convenience,” said Luyendyk. “They are pieces of the same thing when you look at Gondwana. So I thought, ‘Why do you keep naming this collection of pieces as different things?’ ”
Gondwana was formed when Earth’s ancient supercontinent, Pangea, split into two fragments. Laurasia became North America, Asia, and Europe, while Gondwana became Africa, South America, Australia, and Antarctica. But the land masses continued to be reorganized later, with Zealandia breaking Gondwana.
Zealandia was classified as a “microcontinent”, like the island of Madagascar, until 2017. But according to Mortimer, it has all the requirements to be classified as a continent. It has defined limits, occupies an area of more than a million square kilometers and is chosen above the oceanic crust.
The new maps offer more evidence that Zeelandia should be considered the eighth continent, Mortimer added. “If we could disconnect the world’s oceans, it would be pretty clear that Zealandia stands out,” he told Science News in 2017, adding: “If it weren’t for ocean level, we would have long ago recognized Zealandia for what it was: a continent “.
