Introducing Zealandia – The newest continent on Earth

 

Zealandia, a new found continent submerged in the south-west Pacific – is a step closer to being recognized, according to the authors of a new scientific paper.

GSA Today, the journal of the Geological Society of America has published a paper that talks about a vast, continuous expanse of continental crust close to New Zealand. The continental crust is large and separate enough for it to be considered an actual continent.

The authors of the paper argue that the incremental way in which it was discovered shows that even “the large and the obvious in natural science can be overlooked”.

Zealandia covers 4.9 million square km, of which 94% is submerged under water and encompasses New Caledonia along with New Zealand, the Lord Howe Island group and Elizabeth and Middleton reefs.

The size is almost the same as that of the Indian subcontinent and is believed to have broken away from Gondwana, which is claimed to be an ancient supercontinent.

“This is a big piece of ground we’re talking about, even if it is submerged,” said Nick Mortimer, a New Zealand geologist, co-author of the paper.

Geologists have argued in favor of Zealandia being recognized as its own continent intermittently over the past 20 years.

Mapped area of zealandia

The American geophysicist Bruce Luyendyk was the first to use the name Zealandia to a south-west Pacific continent in 1995. The co-authors of the paper say that it has had moderate uptake but was not known widely amongst international scientists.

Mortimer and his fellow co-authors from the GNS Science research institute and Victoria University of Wellington in New Zealand; the Service Géologique of New Caledonia; and the University of Sydney’s School of Geosciences argue that Zealandia has all the necessary geological elements to be considered as a continent.

Mortimer says that it was the first robust, peer-reviewed scientific paper to describe and recognize Zealandia, but the findings would give nothing new for most New Zealand geoscientists. “They probably wonder what all the fuss is about”, he says.

He said he and the other researchers started to piece together the submerged continent with the release of a bathymetric map in 2002.

“That’s when the penny dropped, really … From that point, that map was literally our road map for some crosses, just trying to get rocks out of all the four corners of Zealandia that we could, so we could prove up the geology.”

There had been no formal Zealandia project, he said; it had been “a gradual process of joining the dots”.

“It was a question of confidence, fundamentally, I think, with the accumulation of data and what to do with it.”

Zealandia will possibly be the eighth and the smallest continent in the world after Africa, Antarctica, Asia, Australia/Oceania, Europe, North America, and South America. Asia and Europe are sometimes recognized together as Eurasia.

“It turns out New Zealand isn’t just a couple of small islands at the bottom of the world,” Fairfax Media New Zealand triumphantly reported.

Barry Kohn, a professor of earth sciences at the University of Melbourne, who had done work with Mortimer on Zealandia in the past, said there was a “fair consensus in the scientific community” in favor of its existence.

“It’s pretty clear that that whole area is not part of the ocean. It’s got all the hallmarks of a continent.”

He said rock dredged up from the area was clearly continental crust, “fairly continuous” and defined. More information had been collected over the past few decades to confirm its existence.

However, despite all the evidence in support of it, whether or not Zealandia would be recognized widely as the seventh continent depends on history, said Mortimer.