Advertisement

natureNaturenatureplanet earth
clockPUBLISHED

Zealandia Is Earth's First Continent To Be Completely Mapped, Revealing Ancient Secrets

The eighth continent of the world is almost entirely submerged underwater.

Holly Large - Editorial Assistant

Holly Large

Holly Large - Editorial Assistant

Holly Large

Jr Copy Editor & Staff Writer

Holly is a graduate medical biochemist with an enthusiasm for making science interesting, fun and accessible.

Jr Copy Editor & Staff Writer

Edited by Katy Evans
author

Katy Evans

Managing Editor

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

share380Shares
Zealandia, the eighth continent of the world is almost entirely submerged underwater.

The underwater shelves of continents are difficult to make, making this feat all the more impressive.

Image credit: ManuMata/Shutterstock.com

Listen with
Speechify
0:00
5:00

Zealandia has been kicking about for a good 60 million years, having separated from the supercontinent Gondwana around that time. It’s also almost entirely submerged underwater and wasn’t even formally recognized as a continent until 2017. But now, it’s experiencing something of a resurgence – at least in a research sense – becoming the first continent to be completely mapped and revealing some new secrets to boot.

Creating a full map of a continent was already difficult before Zealandia officially became a thing; all of Earth’s continents have hard-to-explore shelves underwater, meaning geological maps across the planet’s surface are a bit lacking. With 95 percent of Zealandia being submerged, it pretty much takes the biscuit in terms of difficulty.

Advertisement

Thankfully, that didn’t put researchers off. Building upon a paper published back in 2019, an international team of scientists successfully completed the mapping of the 5 million square kilometer (1.9 million square miles) continent.

"We believe Zealandia is the first of Earth's continents to have its basement, sedimentary basins, and volcanic rocks fully mapped out to the continent-ocean boundary," the team wrote in a paper describing the mapping and findings.

Previous research identified that Zealandia’s crust is thinner than the crust of most other continents, but what caused the thinning process was unclear. Using magnetic surveys, the new study uncovered an explosive potential cause – basalt lava rocks indicated there used to be a giant volcanic region. 

Advertisement

It’s thought this region ignited between 100 and 60 million years ago, right around the time Zealandia broke off from Gondwana. “For this period of at least 40 million years, molten magma flooded out of cracks and fissures as the continent stretched and thinned like pizza dough,” explained lead author Nick Mortimer in a statement.

Co-author Wanda Stratford added: "Until now, the role of magma in Gondwana breakup has been underestimated. We can now see these lavas cover an area of 250,000 km2 [96,500 square miles] across the continent - about the size of New Zealand itself.”

Through dating and chemical analysis, the complete map also uncovered a full picture of another key part of Zealandia’s story – its 4000-kilometer-long (around 2,500 miles) granite backbone. Dubbed the Median Batholith, the transcontinental belt of granite is thought to be between 250-100 million years old. 

As for what’s next for Zealandia, Mortimer has some ideas. “While the continent is the first to be completely mapped out to its submarine edges, much exploration and discovery remains. Not just what is where, but when, how, and why the major geological events that have shaped our continent took place.”

Advertisement

The study is published in Tectonics.


ARTICLE POSTED IN

natureNaturenatureplanet earth
  • tag
  • volcanic activity,

  • basalt,

  • Gondwana,

  • planet earth,

  • continent,

  • Zealandia,

  • granite

FOLLOW ONNEWSGoogele News