Zealandia: The Hidden Eighth Continent That Stayed Underwater for Millions of Years

A vast landmass hidden beneath the waters of the South Pacific Ocean is reshaping the way scientists view Earth’s geography. Known as Zealandia, the largely submerged continent was officially recognised by geologists in 2017, despite having existed for millions of years.

Covering nearly five million square kilometres, Zealandia is considered by many researchers to be Earth’s eighth continent. However, unlike the seven traditionally recognised continents, about 94 per cent of its surface lies underwater. Only a few portions, including New Zealand and New Caledonia, remain visible above sea level.

For decades, scientists suspected that the region represented more than a collection of islands and underwater plateaus. The idea gained momentum in 1995 when geophysicist Bruce Luyendyk proposed the name Zealandia for the extensive submerged landmass. It was not until 2017 that a team of geologists presented compelling evidence showing that the area met the scientific criteria required to be classified as a continent.

Researchers found that Zealandia possesses a distinct geological structure, a thick continental crust and clear boundaries separating it from surrounding oceanic crust. These characteristics helped distinguish it from smaller continental fragments and underwater plateaus.

Scientists believe Zealandia was once part of the ancient supercontinent Gondwana, which also included present-day Antarctica, Australia, Africa and South America. Geological forces gradually pulled the landmass apart and caused much of it to sink beneath the ocean over tens of millions of years.

Advances in seafloor mapping, seismic surveys and geological analysis have played a crucial role in uncovering Zealandia’s true extent. The discovery has provided valuable insights into plate tectonics and continental evolution while challenging long-held assumptions about Earth’s surface. Although it remains largely hidden beneath the ocean, Zealandia is now recognised as one of the planet’s most remarkable geological features, offering scientists a new perspective on the history and formation of continents.