Zealandia: The Eighth Elusive Continent That Hid in Plain Sight for Centuries Has Plenty More Secrets to Reveal
For the longest time, speculation about a mysterious eighth continent was rife. Then, in 2017, a group of geologists confirmed that the earth housed eight continents, BBC reported. The continent was named Zealandia and, in the Māori language, Te Riu-a-Māui.
Besides its status as the youngest of all the continents, Zealandia is also the smallest and thinnest, according to the BBC. Almost 94% of the continent is submerged in the water, with only islands like New Zealand peeking out of the ocean.
For centuries, explorers searched for this elusive eighth continent. The geologists who finally discovered the continent found it hidden in plain sight.
"This is an example of how something very obvious can take a while to uncover," noted Andy Tulloch, a geologist at the New Zealand Crown Research Institute GNS Science. Tulloch was part of the team that discovered Zealandia.
Abel Tasman, a Dutch sailor, was the first individual recorded in history to reach the continent, BBC reported. In the 17th century, the European nations tried to claim the large land mass they believed was situated in the Southern Hemisphere. They had named it Terra Australis.
On August 14, 1642, Tasman sailed off with two small ships and ended up in the South Island of New Zealand, BBC reported. He did not have a positive experience with the local Māori people.
After the first day of meeting Tasman, the group attacked a small boat that was passing messages between the Dutch ships. In return, the crew fired a canon.
Several weeks later Tasman left the island, BBC reported. He named the place Moordenaers (Murderers) Bay. The sailor believed that he had discovered the southern continent.
According to geologists' research conducted in 2017, Tasman had just seen a small part of the mysterious continent. Tasman did not return to Zealandia to explore further, because he could not find any commercial prospects there.
The geologists believe there is still much more to learn about the continent, BBC reported.
Most of Zealandia is located beneath 6,560 ft. of water. It's still unclear how Zealandia managed to stay together despite being so thin. It should have disintegrated into microcontinents, but some unknown forces aided it in remaining united.
Another question that the geologists want to explore is how exactly Zealandia ended up submerged inside the water, BBC reported. Currently, the portions of the continent above the sea level are ridges created when Pacific and Australian tectonic plates crumpled together.
Experts are divided on whether the continent was once a dry land or most of it had remained always submerged in the water.
The flora and fauna of the continent also raised questions, BBC reported. Though finding fossilized land animals is rare in the Southern Hemisphere, the remains of several species were located in New Zealand in the 1990s.
Some finds included the rib bones of a giant, long-tailed, long-necked dinosaur known as a Sauropoda; a beaky herbivorous Hypsilophodontidae; and an armored Ankylosaur. The dating technique revealed that the fossils belonged to a period that followed Zealandia splitting from Gondwana.
"There's a long debate about this, about whether it's possible to have land animals without continuous land – and whether without it, they would have been snuffed out," said Rupert Sutherland, a Professor of Geophysics and Tectonics at the Victoria University of Wellington, BBC reported.
A study published by GSA Today explains how Zealandia fulfills all the conditions of being a continent. Continents generally are more elevated in comparison to the oceanic crust.
The landform of Zealandia from every angle is substantially elevated above the surrounding oceanic crust.
Continental crust is conventionally comprised of igneous, metamorphic, and sedimentary rocks – such as granite, schist, and limestone. Zealandia, according to the study by GSA, has this diverse geology.
The continent also fulfills the conventional criteria of thickness and physical properties. Zealandia has a continental crust velocity structure of <7.0 km−1, and a thickness that typically ranges from 10 to 30 km throughout the landform's entire extent to >40 km in parts that fall under South Island.
Sutherland believes that there is still a long way to go to learn the secrets of Zealandia, BBC reported.
"It's quite hard to make discoveries, when everything is 2 km (1.2 miles) underwater, and the layers that you need to sample are 500m (1,640ft) beneath the seabed as well," he pointed out. "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."