A mysterious continent lies beneath New Zealand, says a group of geologists. The findings are published in the latest edition of The Geological Society of America (GSA) Today. However, its designation as a continent is reminiscent of the battle of categorising Pluto as a planet: is Zealandia really a continent, and if it is, who will officially classify it as one?
Zealandia is described as a continuous stretch of crust with an area of about 4.9 million square kilometers, similar in size to the Indian subcontinent. This lost continent is located at approximately 3,000 metres over the ocean crust, says geologist Nick Mortimer, one of the study authors, from GNS Science, New Zealand. Mostly lying under the ocean, only around 6% of the landmass is conspicuous; the latter makes up New Zealand, New Caledonia, together with a handful of little islands. Mortimer explains that the ocean level has thus far prevented us from identifying Zealandia as a continent.
But, is it? Is it really a continent?
The greater part of the predicament lies in the inexistence of an international panel to classify new continents officially. As surprising as this is, the current accepted number of continents is a vague number: some say it is seven, while others say it is six, with Europe and Asia collectively called Eurasia. What do we make of Zealandia, then? It (Zealandia) is relatively new, but the concept of it being a continent has been around since the 1990s. But, it has not been proclaimed as one because noone has been appointed to do the job of naming new continents. Can this be changed? Mortimer has one ‘solution’: the proponents will have to use the name ‘Zealandia’ enough times till it is picked up by everybody else.
Perhaps, there is no agency to confirm new continents because it was once inconceivable to discover new ones. Such is the opinion of structural geologist Keith Klepeis, a proponent of Zealandia’s status as a continent.
Mortimer and many others have been putting evidence together for over ten years now so that Zealandia can be validated as a continent. One of their arguments entails the composition of the landmass: it consists of continental rocks like granite, making it stand out from ocean crust basalt. Furthermore, it is not linked to Australia, as between the two lies a piece of ocean crust. On the other hand, one might argue that Zealandia is too small to be categorised a continent. However, there is no minimum size per se, argues Mortimer, who has also proposed a limit at 1-million-square-kilometer—Zealandia would, then, be the smallest continent, but a continent nevertheless.
Mortimer explains that recognising Zealandia as a continent on its own would open the doors for scientists to study the evolution of landmasses, and to literally solve the puzzle of ancient supercontinents that got separated over time.
The fact remains: Zealandia is not recognised as a continent. Can we use the term “microcontinent”, then, like Madagascar? Mortimer argues that Zealandia is too big to be called one: it is around 6 times larger than Madagascar, one of the largest microcontinent. A geologist from Canada, Richard Ernst, comes up with another term: mini-continent. This would make Zealandia the equivalent of Pluto; the latter was declared a dwarf planet, and not a planet.