Zealandia: the continent we already knew about


Recently, to great interest, the media made an astonishing discovery. Lo and behold, out of nowhere, it was found that New Zealand is the surface portion of an undersea continent. News agencies seized on it. From the B.B.C., to R.T., to C.N.N. it was big news that under the sea was a continent that geologists had decided to call Zealandia. Here was a major discovery that the media had to rush to tell the world.

Except that it is not big news at all. In fact, it is not even news. As a student starting a geology undergraduate degree in 2000, I learnt about it from one of my lecturers then. I have spoken to several people who did geology majors at University – some as much as 45-50 years ago and some relatively recently – and they all clearly remember Zealandia being mentioned in one course or another they did.

On the pin board in my room at home is a map of New Zealand. It has the visible land mass of New Zealand shown in grey. Underneath you can see the 88% of Zealandia that is submerged  – a vast undersea rise running for 900 kilometres out to sea from the Canterbury (about 560 miles).

If one uses a bit of imagination and draws a straight line from the current mouths of the Waitaki and Clutha Rivers, it is quite conceivable that the vast linear collapse under the sea extending for hundreds of kilometres was actually caused by sea bed currents.  A smaller system starts off the coast from where the Buller River runs out to sea. On a map they look just like a river system would in a digital elevation model – a 3 dimensional graphic created from terrain elevation data – showing actual relief.

So, I am rather bemused in all honesty about the fact that the media have only just caught up with something that New Zealand geology students at University have been learning about for half a century. Perhaps not so amusing is that it should be considered news when a look at any geographic information systems (G.I.S.) output based on a bathymetric data set from the National Institute of Water and Atmospherics (N.I.W.A.), would have shown it existed all along.

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