Zealandia
A mostly submerged continent in Oceania, nearly the size of Australia.
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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 concept was proposed by Bruce Luyendyk in 1995, and satellite imagery reveals it to be nearly the size of Australia.
A 2021 study indicates Zealandia is over one billion years old, roughly twice as old as previously estimated. By about 23 million years ago, the landmass may have been completely submerged, and today 94% of it remains beneath the Pacific Ocean. New Zealand is the largest emergent portion, followed by New Caledonia.
Mapping concluded in 2023, showing a total area of approximately 4.9 million square kilometers, making it substantially larger than any other feature termed a microcontinent or continental fragment. It is six times the area of Madagascar, more than half the exposed land of Australia, and larger than the Ontong Java Plateau, Greenland, the Arabian Peninsula, and the Indian subcontinent. Due to its crustal thickness and density, some geologists argue it fulfills all criteria to be considered a continent. Zealandia supports substantial inshore fisheries and contains gas fields, including the Maui gas field near Taranaki.
Offshore mineral resources include ironsands, volcanic massive sulfides, and ferromanganese nodule deposits. The total land area is about 286,660 square kilometers, with New Zealand comprising 93.49% and New Caledonia 6.48%. The human population is approximately 5.4 million, with Auckland as the largest city.
Quick Facts
- 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
Facts from the source article.
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.
Reader's Guide
Zealandia, a largely submerged continental crust in Oceania, broke away from Gondwana 83–79 million years ago and subsided. By about 23 million years ago, it may have been completely underwater, and today 94% of its landmass lies beneath the Pacific Ocean. The name was proposed by Bruce Luyendyk in 1995, and a 2021 study indicated the crust is over one billion years old—twice as old as previously thought. Mapping was completed in 2023.
Its total area is substantially larger than any other microcontinent or continental fragment; it is six times the size of Madagascar and more than twice the size of the Ontong Java Plateau. Some geologists argue it meets all criteria for a continent due to its crustal thickness and density. Zealandia supports inshore fisheries and contains gas fields, including the Maui gas field near Taranaki, with oil exploration permits issued in 2007. Offshore mineral resources include ironsands, volcanic massive sulfides, and ferromanganese nodules.
Biogeographically, New Caledonia and New Zealand host Antarctic flora such as araucarias and podocarps, and a fossilized Jurassic forest of trees related to modern kauri and Norfolk pine is preserved at Curio Bay. A fossil mammal jaw from the Miocene, discovered in Otago in 2006, shows Zealandia once had native land mammals. The landmass has a total human population of about 5.4 million, with Auckland as the largest city. Its recognition reshapes understanding of Earth’s geology, plate tectonics, and the distribution of ancient flora.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Zealandia (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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