Geologists find an eighth continent: Zealandia

You think you know your continents? Think again.

We're taught in elementary school that there are seven continents on Earth -- Africa, Antarctica, Asia, Australia, Europe, North America and South America.

However; science textbooks may be undergoing the biggest shake-up since scientists declared Pluto wasn't a planet. Textbooks across the world might have to add one more continent to that list -- Zealandia.

In a paper published in the Geological Society of America's Journal, researchers explain that Zealandia is a continent that is 94 percent submerged underwater, which is why it took so long for geologists to identify it. The 6 percent that is above water comprises what many know as New Zealand and New Caledonia.

Zealandia spans almost 2 million square miles, a bit larger than India. And while the idea of a mostly submerged continent in the Pacific has been known in the science community for a while, it was only in the last two decades that researchers accumulated enough data and observations to classify it as the world's eighth continent.

Being above water isn't crucial to be defined as a continent. Researchers looked at a different set of criteria, all of which are met by Zealandia. These include:

• elevation above the surrounding area
• distinctive geology
• a well-defined area
• a crust thicker than the regular ocean floor

In 1995, Bruce Luyendyk, a geologist teaching at the University of California Santa Barbara, coined the term "Zealandia" to describe New Zealand, New Caledonia and sections underwater that broke off from an ancient supercontinent, Gondwana.

"I wanted to just lump all of these masses together," Luyendyk told ABC News. "It was really just a convenient way to refer to this area."

There is in fact no scientific body that formally recognises continents. If future research accepts Zealandia on par with the rest so that eventually we might be learning about eight, not seven, continents.