Zealandia: A New Continent

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We are frequently taught that seven continents exist: Africa, Asia, Antarctica, Australia, Europe, North America, and South America.

But according to a new study of Earth’s crust, there’s a seventh geologic continent called “Zealandia,” and it has been hiding under our figurative noses for millennia.

The 11 researchers behind the study say that New Zealand and New Caledonia aren’t merely island chains. Instead, they’re both part of a single, 4.9 million-square-kilometer (1.89 million-square-mile) slab of continental crust that’s distinct from Australia.

They took decades’ worth of newer evidence and examined it with four criteria that geologists use to deem a slab of rock a continent:

  • Land that pokes up relatively high from the ocean floor.
  • A diversity of three types of rocks: igneous (spewed by volcanoes), metamorphic (altered by heat/pressure), and sedimentary (made by erosion).
  • A thicker, less dense section of crust compared with surrounding ocean floor.”
  • Well-defined limits around a large enough area to be considered a continent rather than a microcontinent or continental fragment.”

What’s more, the researchers wrote, rock samples suggest Zealandia is made of the same continental crust that used to be part of Gondwana and that it migrated in ways similar to Antarctica and Australia.

The samples and data also show that Zealandia is not broken up. Instead, plate tectonics have thinned, stretched, and submerged Zealandia over of millions of years.

Today, only about 5% of it is visible — which is part of the reason it took so long to discover.


 

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