Earth still holds remarkable secrets beneath its surface—and sometimes beneath its oceans. In 2017, scientists confirmed the existence of a hidden continent beneath the South Pacific. Now known as Zealandia, this mostly submerged landmass was found hiding in plain sight and has since been dubbed “the eighth continent.” A study published in Tectonics helped solidify its status, offering a new perspective on Earth’s ever-evolving geography.
The long search that began in the 1600s
Although the researchers discovered this new continent in 2017, the hunt began almost 400 years ago. In 1642, Dutch captain Abel Tasman (seen in the above portrait), serving the East India Company, was ordered to explore a Southern Continent. On August 14, 1642, Tasman departed from Batavia with two ships sailing west to Mauritius in the Indian Ocean, according to Princeton University Library.
Tasman named the location “Moordenaers (Murderers) Bay,” and sailed home, never to return to this land, although he did believe that he had discovered a great new continent.
Naming and defining Zealandia
It was nearly 375 years after Tasman’s voyage that geologists stumbled upon this mainland. They announced the discovery by naming it “Zealandia,” based on the suggestion of American geophysicist Bruce Luyendyk who described this region in 1995. Zealandia is translated to “Te Riu-a-Māui” in the Māori language.
In a paper, researchers from GNS Science of New Zealand documented that they had to dredge rock samples from the Fairway Ridge to the Coral Sea to analyze the rock geochemically and understand the underwater makeup of Zealandia. Led by Nick Mortimer, they scanned the northern two-thirds of the submerged area, where they unearthed pebbly and cobbley sandstone, fine-grain sandstone, mudstone, bioclastic limestone, and basaltic lava from a variety of periods as concluded by their radiocarbon dating.
Ancient rocks with a story to tell
The rocks and stones were found to be roughly 95 million years old, from the Late Cretaceous period. The granite and volcanic pebbles were estimated to be 130 million years old, the Early Cretaceous period. The basalts however were newer, probably about 40 million years old, and from the Eocene period. “It is kind of cool,” said Mortimer, per BBC. Andy Tulloch, a geologist at the New Zealand Crown Research Institute GNS Science, who was part of the research team, added, “This is an example of how something very obvious can take a while to uncover.”
Mostly submerged, yet massive
Although Zealandia is a vast continent that spans an expanse stretched for 4.9 million square kilometers, around six times the size of Madagascar, most of it is submerged under the South Pacific Ocean. Only the area at the Ball’s Pyramid on Lord Howe Island rises above the water’s veil. It is the smallest, thinnest, and youngest of all known continents.
Usually, the continental crust is about 40 kilometers deep, thicker than the oceanic crust which is about 10 kilometers. The researchers proposed that since Zealandia ended up stretched too much, its crust became thinner, around 20 kilometers, and finally disappeared under the sea. With 95 percent of its territory submerged beneath the ocean’s depths, Zealandia prowls on planet Earth as a lair possessing an enigmatic charm of mysterious historical elements and ancient stories.
This article originally appeared last year.
