Zealandia, a long-hidden continent lurks beneath New Zealand according to geologists. However, as nobody is in charge of officially designating a new continent, individual scientists will ultimately have to judge for themselves.
A team of geologists have argued that Zealandia is a continuous expanse of continental crust covering around 4.9 million square kilometers. That’s about the size of the Indian subcontinent. Unlike the other mostly dry continents, around 94 percent of Zealandia hides beneath the ocean. Only New Zealand, New Caledonia and a few small islands peek above the waves.
“If we could pull the plug on the world’s oceans, it would be quite clear that Zealandia stands out about 3,000 meters above the surrounding ocean crust,” says study coauthor Nick Mortimer, a geologist at GNS Science in Dunedin, New Zealand. “If it wasn’t for the ocean level, long ago we’d have recognized Zealandia for what it was — a continent.”
The landmass faces an uphill battle for continent status, though. Unlike planets and slices of geologic time, no international panel exists to officially rubber-stamp a new continent. The current number of continents is already vague — usually given as six or seven, with geologists referring to Europe and Asia collectively as Eurasia. Proponents will just have to start using the term “Zealandia” and hope it catches on, Mortimer says.
While only 6 percent of Zealandia rises above sea level (dark gray), including New Zealand, swaths of other continents are also submerged along their margins (light-shaded regions).
This odd path forward stems from the simple fact that nobody expected another addition to the continental ranks, says Keith Klepeis, a structural geologist at the University of Vermont in Burlington who supports Zealandia’s inclusion. The discovery illustrates that “the large and obvious can be overlooked in science,” he says.
Size is a sticking point, though. No minimum size requirement exists for continents. Mortimer and colleagues propose a 1-million-square-kilometer cutoff point. If this limit is accepted, Zealandia would be the scrawniest continent by far, little more than three-fifths the size of Australia. (Both submerged and dry areas contribute to a continent’s overall size.)