The missing continent it took 375 years to find

It took scientists 375 years to discover the eighth continent of the world, which has been hiding in plain sight all along. But mysteries still remain.

Zealandia continent

It was 1642 and Abel Tasman was on a mission. The experienced Dutch sailor, who sported a flamboyant moustache, bushy goatee and penchant for rough justice – he later tried to hang some of his crew on a drunken whim – was confident of the existence of a vast continent in the southern hemisphere, and determined to find it.

At the time, this portion of the globe was still largely mysterious to Europeans, but they had an unshakeable belief that there must be a large land mass there – pre-emptively named Terra Australis – to balance out their own continent in the North. The fixation dated back to Ancient Roman times, but only now was it going to be tested.

And so, on 14 August, Tasman set sail from his company’s base in Jakarta, Indonesia, with two small ships and headed west, then south, then east, eventually ending up at the South Island of New Zealand. His first encounter with the local Māori people (who are thought to have settled there several centuries earlier) did not go well: on day two, several paddled out on a canoe, and rammed a small boat that was passing messages between the Dutch ships. Four Europeans died. Later, the Europeans fired a cannon at 11 more canoes – it’s not known what happened to their targets. 

And that was the end of his mission – Tasman named the fateful location Moordenaers (Murderers) Bay, with little sense of irony, and sailed home several weeks later without even having set foot on this new land. While he believed that he had indeed discovered the great southern continent, evidently, it was hardly the commercial utopia he had envisaged. He did not return.

(By this time, Australia was already known about, but the Europeans thought it was not the legendary continent they were looking for. Later, it was named after Terra Australis when they changed their minds).

Little did Tasman know, he was right all along. There was a missing continent.

In 2017, a group of geologists hit the headlines when they announced their discovery of Zealandia –Te Riu-a-Māui in the Māori language. A vast continent of 1.89 million sq miles (4.9 million sq km) it is around six times the size of Madagascar.

Though the world’s encyclopaedias, maps and search engines had been adamant that there are just seven continents for some time, the team confidently informed the world that this was wrong. There are eight after all – and the latest addition breaks all the records, as the smallest, thinnest, and youngest in the world. The catch is that 94% of it is underwater, with just a handful of islands, such as New Zealand, thrusting out from its oceanic depths. It had been hiding in plain sight all along.

“This is an example of how something very obvious can take a while to uncover,” says Andy Tulloch, a geologist at the New Zealand Crown Research Institute GNS Science, who was part of the team that discovered Zealandia.

But this is just the beginning. Four years on and the continent is as enigmatic as ever, its secrets jealously guarded beneath 6,560 ft (2km) of water. How was it formed? What used to live there? And how long has it been underwater?

A laborious discovery

In fact, Zealandia has always been difficult to study.

More than a century after Tasman discovered New Zealand in 1642, the British map-maker James Cook was sent on a scientific voyage to the southern hemisphere. His official instructions were to observe the passing of Venus between the Earth and the Sun, in order to calculate how far away the Sun is.

A (literal) twist

Another lingering mystery can be found in Zealandia’s shape.

“If you look at a geological map of New Zealand, there are two things that really stand out,” says Sutherland. One of these is Alpine Fault, a plate boundary that runs along the South Island and is so significant, it can be seen from space.

The second is that the geology of New Zealand – as well as that of the wider continent – is oddly bent. Both are split in two by a horizontal line, which is where the Pacific and Australian tectonic plates meet. At this exact point, it looks like someone has taken the lower half and twisted it away, so that not only do the previously-continuous ribbons of rock no longer line up, but they are almost at right angles.

An easy explanation for this is that the tectonic plates moved, and somehow deformed them out of shape. But exactly how or when this happened is still totally unresolved.

“There are various interpretations, but this is quite a large unknown thing,” says Tulloch.

Sutherland explains that the continent is unlikely to give up all its secrets anytime soon. “It’s quite hard to make discoveries, when everything is 2km (1.2 miles) underwater, and the layers that you need to sample are 500m (1,640ft) beneath the seabed as well,” he says. “It’s really challenging to go out and explore a continent like that. So, it just takes a lot of time, money and effort to go out and ships and survey regions.”

If nothing else, the world’s eighth continent surely shows that – nearly 400 years after Tasman’s quest – there is still plenty to be discovered.

Source: BBC