Zealandia
A mostly submerged continent in Oceania, nearly the size of Australia.
Zealandia, also known as Te Riu-a-Māui 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. The name was proposed by Bruce Luyendyk in 1995, and satellite imagery reveals it to be nearly the size of Australia. A 2021 study suggests Zealandia is over one billion years old, roughly twice as old as previously thought. By about 23 million years ago, the landmass may have been completely submerged; today, 94% remains beneath the Pacific Ocean. New Zealand is the largest portion above sea level, followed by New Caledonia. Mapping concluded in 2023, showing a total area of approximately 4,900,000 square kilometres. This makes it substantially larger than any other microcontinent or continental fragment—six times the area of Madagascar and more than half the exposed land of Australia. It also surpasses the Ontong Java Plateau, Greenland, the Arabian Peninsula, and the Indian subcontinent. Due to its crustal thickness and density, some geologists argue Zealandia fulfills all criteria to be considered a continent. It supports substantial inshore fisheries and contains gas fields, including the Maui field near Taranaki. Offshore mineral resources include ironsands, volcanic massive sulfides, and ferromanganese nodule deposits. The total land area is 286,660 square kilometres, with New Zealand comprising 93.49%, New Caledonia 6.48%, and small Australian territories the remainder. The human population is about 5.4 million, with Auckland as the largest city.
- Submerged percentage
- 94%
- Oldest estimated age
- over one billion years
- Largest above-sea part
- New Zealand
- Second largest above-sea part
- New Caledonia
- Classification debated
- 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 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 an important part in the origin of the Pacific Ocean's volcanic 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. This verdict was widely covered in the news media. Geologist Nick Mortimer commented that if it were not for the ocean level, it would have been recognised as such long ago. Its area is six times that of the next-largest microcontinent, Madagascar, and more than half the exposed land area of the Australian continent. Zealandia is also substantially larger than the Arabian Peninsula and the Indian subcontinent. The landmass supports unique biogeography, featuring Antarctic flora such as araucarias and podocarps, and a fossilized forest from the Jurassic period.
Did You Know?
- Zealandia is almost entirely submerged, with 94% of its landmass beneath the Pacific Ocean.
- Zealandia is more than twice the size of the Ontong Java Plateau, the world's largest intraoceanic large igneous province.
- The name Zealandia is a latinate name for New Zealand, itself referring to the Dutch Zeeland province.
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