Zealandia Explained

Zealandia (pronounced), also known as Maori: '''Te Riu-a-Māui''' (Māori)[1] or Tasmantis (from Tasman Sea),[2] [3] is an almost entirely submerged mass of continental crust in Oceania that subsided after breaking away from Gondwana 83–79 million years ago.[4] It has been described variously as a submerged continent, continental fragment, and microcontinent. The name and concept for Zealandia was proposed by Bruce Luyendyk in 1995,[5] and satellite imagery shows it to be almost the size of Australia.[6] A 2021 study suggests Zealandia is over a billion years old, about twice as old as geologists previously thought.[7] [8]

By approximately 23 million years ago, the landmass may have been completely submerged.[9] [10] Today, most of the landmass (94%) remains submerged beneath the Pacific Ocean.[11] New Zealand is the largest part of Zealandia that is above sea level, followed by New Caledonia.

Mapping of Zealandia concluded in 2023.[12] With a total area of approximately 4900000km2, Zealandia is substantially larger than any features termed microcontinents and continental fragments. If classified as a microcontinent, Zealandia would be the world's largest microcontinent. Its area is six times the area of the next-largest microcontinent, Madagascar, and more than half the area of the Australian continent. Zealandia is more than twice the size of the largest intraoceanic large igneous province (LIP) in the world, the Ontong Java Plateau (approximately), and the world's largest island, Greenland . Zealandia is also substantially larger than the Arabian Peninsula, the world's largest peninsula, and the Indian subcontinent . Due to these and other geological considerations, such as crustal thickness and density,[13] some geologists from New Zealand, New Caledonia, and Australia have concluded that Zealandia fulfills all the requirements to be considered a continent rather than a microcontinent or continental fragment. Geologist Nick Mortimer commented that if it were not for the ocean level, it would have been recognised as such long ago.[14]

Zealandia supports substantial inshore fisheries and contains gas fields, of which the largest known is the New Zealand Maui gas field, near Taranaki. Permits for oil exploration in the Great South Basin were issued in 2007.[15] Offshore mineral resources include ironsands, volcanic massive sulfides and ferromanganese nodule deposits.[16]

Etymology

GNS Science recognises two names for the landmass. In English, the most common name is Zealandia, a latinate name for New Zealand; the name was coined in the mid-1990s and became established through common use. In the Māori language, the landmass is named Maori: Te Riu-a-Māui, meaning 'the hills, valleys, and plains of Māui'.[1]

Geology

See also: Geology of Zealandia, Geology of New Zealand, Geography of New Caledonia and Geology of New Caledonia.

Biogeography

New Caledonia is at the northern end of the ancient continent, while New Zealand rises at the plate boundary that bisects it. These land masses constitute two outposts of the Antarctic flora, featuring araucarias and podocarps. At Curio Bay, logs of a fossilized forest closely related to modern Kauri and Norfolk pine can be seen that grew on Zealandia approximately 180 million years ago during the Jurassic period, before it split from Gondwana.[17] The trees growing in these forests were buried by volcanic mud flows and gradually replaced by silica to produce the fossils now exposed by the sea.

As sea levels drop during glacial periods, more of Zealandia becomes a terrestrial environment rather than a marine environment. Originally, it was thought that Zealandia had no native land mammal fauna, but the discovery in 2006 of a fossil mammal jaw from the Miocene in the Otago region demonstrates otherwise.[18]

Political divisions

The total land area (including inland water bodies) of Zealandia is 286660.25km2. Of this, New Zealand comprises the overwhelming majority, at 267988km2, or 93.49%) that includes the mainland (North Island and South Island), nearby islands, and most outlying islands, including the Chatham Islands, the New Zealand Subantarctic Islands, the Solander Islands, and the Three Kings Islands (but not the Kermadec Islands or Macquarie Island (Australia), which are part of the rift).[19]

New Caledonia and the islands surrounding it comprise some 18576km2 or 6.48%) and the remainder is made up of various territories of Australia including the Lord Howe Island Group (New South Wales) at 56km2 or 0.02%), Norfolk Island at 35km2 or 0.01%), as well as the Cato, Elizabeth, and Middleton reefs (Coral Sea Islands Territory) with 5.25km2.[20]

Population

the total human population of Zealandia is approximately 5.4 million people. The largest city is Auckland with about 1.7 million people; roughly one-third of the total population of the continent.

See also

External links

Notes and References

  1. Web site: The origin and meaning of the name Te Riu-a-Māui/Zealandia . www.gns.cri.nz . . 11 August 2020 . 2 May 2019.
  2. Book: Flannery . Tim . The Future Eaters: An Ecological History of the Australasian Lands and People . 2002 . Grove Press . 978-0-8021-3943-6 . 42 . 26 December 2020 . en.
  3. Book: Danver, Steven L. . 22 December 2010 . Popular Controversies in World History: Investigating History's Intriguing Questions . ABC-CLIO . 187 . 978-1-59884-078-0 . Zealandia or Tasmantis, with its 3.5 million square km territory being larger than Greenland, ... . live . https://web.archive.org/web/20160805230513/https://books.google.com.tw/books?id=slVobUjdzGMC&pg=PA187&lpg=PA187&dq=%22Zealandia%22+%22Tasmantis%22&source=bl&ots=FHEvzkPyk9&sig=QdDerZW6Atj9I3Z7GZq0vSrwTGc&hl=zh-TW&sa=X&ved=0ahUKEwif1qGc5szNAhWCKZQKHQCADa8Q6AEIVjAI#v=onepage&q=%22Zealandia%22%20%22Tasmantis%22&f=false . 5 August 2016 . dmy-all.
  4. Gurnis, M., Hall, C.E., and Lavier, L.L., 2004, Evolving force balance during incipient subduction: Geochemistry, Geophysics, Geosystems, v. 5, Q07001, https://doi.org/10.01029/02003GC000681
  5. Luyendyk . Bruce P. . Bruce P. Luyendyk . April 1995 . Hypothesis for Cretaceous rifting of east Gondwana caused by subducted slab capture . Geology . 23 . 4 . 373–376 . 10.1130/0091-7613(1995)023<0373:HFCROE>2.3.CO;2. 1995Geo....23..373L .
  6. Web site: Gorvett . Zaria . The missing continent it took 375 years to find . BBC . 9 February 2021 . 8 February 2021.
  7. Turnbull . R.E. . Schwartz . J.J. . Fiorentini . M.L. . Jongens . R. . Evans . N.J. . Ludwig . T. . McDonald . B.J. . Klepeis . K.A. . 2021-08-01 . A hidden Rodinian lithospheric keel beneath Zealandia, Earth's newly recognized continent . Geology . en . 49 . 8 . 1009–1014 . 10.1130/G48711.1 . 0091-7613. free . 2021Geo....49.1009T .
  8. Web site: A fragment of a mysterious 8th continent is hiding under New Zealand - and it's twice as old as scientists thought . Business Insider . 14 Aug 2021. Aylin Woodward .
  9. News: Searching for the lost continent of Zealandia. . 29 September 2007 . 9 October 2007 . We cannot categorically say that there has always been land here. The geological evidence at present is too weak, so we are logically forced to consider the possibility that the whole of Zealandia may have sunk..
  10. Book: Campbell, Hamish . In Search of Ancient New Zealand . Gerard Hutching . 2007 . . North Shore, New Zealand . 978-0-14-302088-2 . 166–167.
  11. Book: Wood . Ray . Vaughan . Stagpoole . Ian . Wright . Bryan . Davy . Phil . Barnes . New Zealand's Continental Shelf and UNCLOS Article 76 . 22 February 2007 . Institute of Geological and Nuclear Sciences series 56 . NIWA technical report 123 . 2003 . Institute of Geological and Nuclear Sciences Limited . National Institute of Water and Atmospheric Research . Wellington, New Zealand . 16 . The continuous rifted basement structure, thickness of the crust, and lack of seafloor spreading anomalies are evidence of prolongation of the New Zealand land mass to Gilbert Seamount. . dead . https://web.archive.org/web/20070221051420/http://www.gns.cri.nz/research/marine/images/unclosbook_print.pdf . 21 February 2007 . dmy-all.
  12. . en-US . Earth's Hidden Eighth Continent Is No Longer Lost . Science > Our Planet . Newcomb . Tim . 0032-4558.
  13. News: Zealandia: Is there an eighth continent under New Zealand? . 2017-02-17 . BBC News . 2017-03-26 . en-GB . live . https://web.archive.org/web/20170328203049/http://www.bbc.com/news/world-asia-39000936 . 28 March 2017 . dmy-all.
  14. Web site: Is Zealandia a continent? . Thomas . Sumner . 2017-03-13 . Science News for Students . Society for Science and the Public . 2021-12-22 .
  15. Web site: Great South Basin – Questions and Answers . 11 July 2007 . 18 April 2008 . live . https://web.archive.org/web/20081014080132/http://www.crownminerals.govt.nz/cms/about/media-centre/great-south-basin-media-pack-1/great-south-basin-questions-and-answers . 14 October 2008 . dmy-all.
  16. Web site: New survey published on NZ mineral deposits . 30 May 2007 . 18 April 2008 . live . https://web.archive.org/web/20081016202631/http://www.crownminerals.govt.nz/cms/news/2006/new-survey-published-on-nz-mineral-deposits . 16 October 2008 . dmy-all.
  17. Web site: Fossil forest: Features of Curio Bay/Porpoise Bay . https://web.archive.org/web/20081017015051/http://www.doc.govt.nz/templates/page.aspx?id=35598 . 17 October 2008 . 6 November 2007.
  18. Book: In Search of Ancient New Zealand . Campbell . Hamish . Gerard Hutching . 2007 . Penguin Books . North Shore, New Zealand . 978-0-14-302088-2 . 183–184.
  19. Web site: The Lost Continent of Zealandia. 2020-12-15. www.virtualoceania.net.
  20. https://data.gns.cri.nz/tez/index.html?map=TRAMZ-Bathymetric Detailed map of Zealandia
  21. Web site: Population Stats NZ. 2021-04-21. www.stats.govt.nz.
  22. Web site: 268 767 habitants en 2014. . ISEE . 2014-11-16 . live . https://web.archive.org/web/20141113142325/http://www.isee.nc/population/recensement/structure-de-la-population-et-evolutions . 13 November 2014 . dmy-all .
  23. Web site: 2016 Census QuickStats: Norfolk Island. 2021-04-21. quickstats.censusdata.abs.gov.au. en. 7 May 2019. https://web.archive.org/web/20190507211725/https://quickstats.censusdata.abs.gov.au/census_services/getproduct/census/2016/quickstat/SSC90004?opendocument. dead.

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