For almost 400 years, a massive underwater landmass known as Zealandia was hidden beneath the Pacific Ocean. Covering nearly two million square miles, it’s bigger than India and about two-thirds the size of Australia. Surprisingly, it didn’t appear on maps or in textbooks until recently.
In 2017, geologists made an exciting announcement: Zealandia is a continent. Not a tiny one or just a plateau, but a real continent with its own crust and geological features, all connected to the ancient supercontinent Gondwana. The twist? Most of Zealandia, around 94%, is underwater.
This wasn’t a sudden discovery. For decades, scientists gathered data—rock samples, gravity maps, and sediment studies. But it took special technology to piece everything together. Zealandia’s reawakening highlights the importance of ocean exploration and expands our understanding of our planet.
However, this recognition raises even more questions: Why did Zealandia sink? How was it overlooked for so long? And what else might be hiding beneath the waves?
The modern classification of Zealandia came from a 2017 study published in GSA Today. It detailed how Zealandia met the criteria for a continent. It has significant elevation, a distinct geological structure, a defined area, and a crust thicker than regular ocean floor. The authors argued, “Zealandia is a coherent continent and should be recognized as such.”
The reason it remained hidden? Depth. Much of Zealandia lies over 6,500 feet (2 kilometers) underwater. Traditional mapping couldn’t reach it. Cutting-edge tools like satellite gravity mapping and deep-ocean drilling finally made its true size visible, spanning around 4.9 million square kilometers, according to BBC Future.
Interestingly, Zealandia’s continental crust is thin—only about 20 kilometers thick, unlike the typical 30 to 45 kilometers seen in other continents. This may explain why it sank after breaking off from Gondwana roughly 85 million years ago, as supported by geological studies.
Historically, the concept of a southern landmass isn’t new. In 1642, Dutch explorer Abel Tasman sailed in search of Terra Australis, a presumed continent in the South. Although he didn’t discover the full extent of Zealandia, he unknowingly traveled over a submerged continental shelf.
Historical maps tell a similar story. Early cartographers, influenced by Ptolemy, imagined vast southern continents well into the 17th and 18th centuries. Despite being speculative, these ideas hinted at Zealandia’s eventual reveal.
The first real scientific proposal came in 1895 from Scottish naturalist Sir James Hector, who suggested that New Zealand was part of a submerged continent. Yet, his findings faded into obscurity.
The term Zealandia emerged in the 1990s when U.S. geophysicist Bruce Luyendyk advanced the idea of a unified continent beneath the waves. Research efforts gained momentum, especially after the United Nations Convention on the Law of the Sea presented an opportunity for economic claims if Zealandia could be categorized as part of New Zealand’s continental shelf.
In 2017, the International Ocean Discovery Program conducted six drilling missions in Zealandia. The cores they collected, reaching over 4,100 feet deep, revealed signs of ancient marine life, including microfossils and pollen. This evidence hints that parts of Zealandia might have been land long ago.
Fossils of dinosaurs, such as a sauropod and an ankylosaur, were found in New Zealand and the Chatham Islands. These fossils date back after Zealandia split from Gondwana, suggesting that some parts were above water for a significant time.
Yet, the specifics of Zealandia’s submergence remain unclear. Some geologists argue that it all went underwater around 25 million years ago, with regions like New Zealand rising later. Others believe some areas might have stayed dry throughout their history.
As Zealandia continues to intrigue researchers, the quest for knowledge about our planet’s hidden landscapes goes on. It reminds us of the unexplored wonders lying beneath the ocean’s surface and invites curiosity about what else remains to be discovered.
