Zealandia shown on a map with the other seven continents. Map: GNS Science
Zealandia, an enormous landmass in the Southwest Pacific Ocean whose highest mountains are the islands of New Zealand and New Caledonia, could be recognized as the Earth’s 8th continent.
In a paper published in the Geological Society of America’s Journal, whose lead author is New Zealand geologist Nick Mortimer, scientists argue that Zealandia constitutes a full-fledged continent even though 94% of its surface is under water.
The research is co-authored by scientists 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.
“The scientific value of classifying Zealandia as a continent is much more than just an extra name on a list,” the researchers said.
“That a continent can be so submerged yet unfragmented” could be of use for “exploring the cohesion and breakup of continental crust,“ they argued.
The Smallest Continent
The proposed continent of Zealandia is said to have a territory of about 5 million square kilometers (1.9 million square miles), with only a few islands sticking out above the Pacific surface: New Zealand’s North and South Islands, New Caledonia, Norfolk Island, the Lord Howe Island group and Elizabeth and Middleton reefs.
This is about the size of the Indian Subcontinent. If the notion of Zealandia being a continent in its own right gains mainstream traction, it will be the smallest of the Earth’s continents.
The total area of the neighboring continent of Australia, the smallest one at present, is about 30% larger.
Zealandia is thought to have broken away from the southern supercontinent of Gondwana, and sank between 60 and 85 million years ago.
The authors of the research argued in favor of Zealandia’s recognition as a continent, even though it is almost completely submerged, based on its elevation above its surroundings, its unique geology and definition, and the fact that it exhibits a thicker crust than the regular ocean floor.
“This is a big piece of ground we’re talking about, even if it is submerged," New Zealand geologist Nick Mortimer has told The Guardian Australia.
Zealandia covers nearly 5 million square kilomenters, of which 94% is under water. Maps: GNS Science
Gaining ‘Continental’ Recognition
It is noted that geologists have argued on and off in favor of Zealandia becoming over the past 20 years.
The name “Zealandia" was first used for the landmass submerged in the Southwest Pacific by American geophysicist Bruce Luyendyk back in 1995.
Since then, the paper’s co-authors say, it has had “moderate uptake" but was still not broadly known to international scientists.
Mortimer described the paper on Zealandia as the first robust, peer-reviewed scientific article on the proposed continent, which, however, contained nothing new for New Zealand geologists who are familiar with the topic.
He revealed the new paper was based on research which started in 2002, and 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," the geologist said.
As there is no international scientific body in charge of officially recognizing continents, Zealandia’s mainstream acceptance as a continent is likely to take a while, and is still uncertain.