Zealandia: The missing continent that took 375 years to be found 

You’ve likely been taught that there are 7 continents on Earth. However, now there is evidence for an eighth one hidden mostly underwater. ‘Zealandia’ was given the formal status of Earth’s eighth continent in the year 2017.  

Well, this is not surprising! What you will be amazed to know is that there were not always seven continents. Australia was found by Captain James Cook 250 years ago while Antarctica was identified in 1912. That is, the number of continents has kept on changing since the evolution of the Earth. Plate tectonics and continental drift  have forced changes in continental composition and their location for millions of years.  

How was it found? 

The first real clues of Zealandia's existence were gathered by the Scottish naturalist Sir James Hector, who attended a voyage to survey a series of islands off the southern coast of New Zealand in 1895. After studying their geology, he concluded that New Zealand is the remnant of a mountain chain that formed the crest of a great continental area that stretched far to the south and east, and which is now submerged. Then in the 1960s, geologists finally agreed on a definition of what a continent is – broadly, a geological area with a high elevation, a wide variety of rocks, and a thick crust. It also has to be big. Geophysicist Bruce Luyendyk coined the term ‘Zealandia’ in 1995 and after that, the search to find the missing continent widened and a group of geologists made the final discovery in 2017.  

But what makes Zealandia a continent?  

Scientists say that Zealandia fits all the criteria to be a continent. Even though it is submerged, its geology is much closer to continental crust than oceanic crust. Continental crust tends to be made up of igneous, metamorphic and sedimentary rocks – like granite, schist and limestone, while the ocean floor is usually just made of igneous ones such as basalt. 

This is possible. The theory is that Zealandia broke away from the supercontinent Gondwanaland about 80 million years ago and for the past 23 million years, 94% of the continent has been submerged with only above-water landmasses making up a few Pacific islands including New Zealand.  
 

Location and geology 

In total, the new continent is 5 million square km, about half the size of Australia, located east of Australia, beneath modern-day New Zealand. In addition to New Zealand, the continent encompasses the island of New Caledonia – a French colony famous for its dazzling lagoons – and the tiny Australian territories of Lord Howe Island and Ball's Pyramid.  

Zealandia generally enjoys a mild temperate climate. Its largest islands have glaciers, the largest being Tasman Glacier on the South Island. Activity from the last glacial period also carved out many fjords and valleys. The tropical climate of New Caledonia, on the other hand, has more in common with Oceania and the South Pacific. 
 

Zealandia is a very tectonically active region. Part of it is on the Australian plate, while the other part is on the Pacific plate. Both the North and South Islands have volcanic mountain ranges running through their centres.  

 The submerged part of Zealandia is rich in mineral deposits, although New Zealand's government strictly controls undersea mining activity. There are also many natural gas fields scattered throughout Zealandia. The Maui natural gas field in the Tasman Sea is the largest.