Zealandia
A mostly submerged continent in Oceania, nearly the size of Australia.
Zealandia, also known as Te Riu-a-Māui (Māori) or Tasmantis, is an almost entirely submerged mass of continental crust in Oceania. It subsided after breaking away from Gondwana 83–79 million years ago and has been described variously as a submerged continent, continental fragment, and microcontinent.
- submerged_percentage
- 94%
- oldest_estimated_age
- over one billion years
- largest_emergent_landmass
- New Zealand
- second_largest_emergent_landmass
- New Caledonia
- classification_dispute
- submerged continent, microcontinent, or continental fragment
Lore & Background
Its crust is thinner than normal continents, about 20 km thick. Compression uplifted the Southern Alps, while subduction of the Pacific Plate led to extensive volcanism, including the Coromandel and Taupō Volcanic Zones. Volcanism on Zealandia occurred repeatedly before, during, and after its rifting from Gondwana. During the Miocene, the northern section may have slid over a stationary hotspot, forming the Lord Howe Seamount Chain. Zealandia may have played a part in the origin of the Pacific Ring of Fire. Zealandia supports substantial inshore fisheries and contains gas fields, including the New Zealand Maui gas field. Offshore mineral resources include ironsands, volcanic massive sulfides, and ferromanganese nodule deposits.
Reader's Guide
Zealandia matters because it challenges traditional definitions of continents. If classified as a microcontinent, it would be the world's largest. Geologist Nick Mortimer commented that if not for the ocean level, it would have been recognised as a continent long ago. Its recognition has implications for understanding Earth's geology, plate tectonics, and the biogeography of the Antarctic flora found on New Caledonia and New Zealand.
Did You Know?
- Zealandia is over one billion years old, about twice as old as geologists previously thought.
- By approximately 23 million years ago, the landmass may have been completely submerged.
- The name Zealandia is a latinate name for New Zealand, referring to the Dutch Zeeland province.
Frequently Asked Questions
What is Zealandia?
Zealandia is a vast mass of continental crust in Oceania, roughly 94% of which lies beneath the ocean surface. It is also called Te Riu-a-Māui in Māori or Tasmantis in some geological literature, and its classification as a full continent versus a microcontinent or continental fragment remains debated.
How big is Zealandia?
At approximately 4.9 million square kilometers, Zealandia is nearly the size of Australia. It ranks among the largest continental crust masses on Earth despite most of it being hidden underwater.
Which parts of Zealandia are still above water?
New Zealand is the largest emergent landmass on Zealandia, with New Caledonia as the second-largest. The remaining 94% of the continental platform sits submerged beneath the Pacific Ocean.
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