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Coordinates : 40°S 170°E / 40°S 170°E / -40; 170 Topography of Zealandia. The linear ridges running north-northeast (Colville to the west and Kermadec to the east, separated by the Havre Trough and Lau Basin
Lau Basin
) and southwest (the Resolution Ridge
Ridge
System ) away from New Zealand
New Zealand
are not considered part of the continental fragment , nor are Australia
Australia
(upper left), Fiji
Fiji
or Vanuatu
Vanuatu
(top centre).

ZEALANDIA ( /ziːˈlændiə/ ), also known as the NEW ZEALAND CONTINENT or TASMANTIS, is a nearly submerged mass of continental crust that sank after breaking away from Australia
Australia
60–85 million years ago, having separated from Antarctica
Antarctica
between 85 and 130 million years ago. It has variously been described as a continental fragment , a microcontinent and a continent . The name and concept for Zealandia
Zealandia
were proposed by Bruce Luyendyk in 1995.

The land mass may have been completely submerged about 23 million years ago, and most of it (93%) remains submerged beneath the Pacific Ocean
Pacific Ocean
. With a total area of approximately 4,920,000 km2 (1,900,000 sq mi), it is the world's largest current microcontinent , more than twice the size of the next-largest microcontinent and more than half the size of the Australian continent . As such, and due to other geological considerations, such as crustal thickness and density, it is arguably a continent in its own right. This was the argument which made news in 2017, when geologists from New Zealand
New Zealand
, New Caledonia
New Caledonia
and Australia
Australia
concluded that Zealandia
Zealandia
fulfills all the necessary requirements to be considered a continent, rather than a microcontinent or continental fragment.

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

CONTENTS

* 1 Geology

* 1.1 Classification as a continent

* 2 Biogeography * 3 Political divisions * 4 Population * 5 References * 6 Further reading * 7 External links

GEOLOGY

Topographic map of Zealandia
Zealandia

Zealandia
Zealandia
is largely made up of two nearly parallel ridges, separated by a failed rift , where the rift breakup of the continent stops and becomes a filled graben . The ridges rise above the sea floor to heights of 1,000–1,500 m (3,300–4,900 ft), with infrequent rocky islands rising above sea level . The ridges are continental rock, but are lower in elevation than normal continents because their crust is thinner than usual, approximately 20 km (12 mi) thick, and consequently they do not float as high above the Earth's mantle .

About 25 million years ago, the southern part of Zealandia
Zealandia
(on the Pacific Plate ) began to shift relative to the northern part (on the Indo-Australian Plate ). The resulting displacement by approximately 500 km (310 mi) along the Alpine Fault
Alpine Fault
is evident in geological maps. Movement along this plate boundary has also offset the New Caledonia Basin from its previous continuation through the Bounty Trough .

Compression across the boundary has uplifted the Southern Alps , although due to rapid erosion their height reflects only a small fraction of the uplift. Farther north, subduction of the Pacific Plate has led to extensive volcanism, including the Coromandel and Taupo Volcanic Zones . Associated rifting and subsidence has produced the Hauraki Graben
Graben
and more recently the Whakatane Graben
Graben
and Wanganui Basin.

Volcanism on Zealandia
Zealandia
has also taken place repeatedly in various parts of the continental fragment before, during and after it rifted away from the supercontinent Gondwana . Although Zealandia
Zealandia
has shifted approximately 6,000 km (3,700 mi) to the northwest with respect to the underlying mantle from the time when it rifted from Antarctica, recurring intracontinental volcanism exhibits magma composition similar to that of volcanoes in previously adjacent parts of Antarctica
Antarctica
and Australia.

This volcanism is widespread across Zealandia
Zealandia
but generally of low volume apart from the huge mid to late Miocene
Miocene
shield volcanoes that developed the Banks and Otago
Otago
Peninsulas . In addition, it took place continually in numerous limited regions all through the Late Cretaceous and the Cenozoic
Cenozoic
. However, its causes are still in dispute. During the Miocene
Miocene
, the northern section of Zealandia
Zealandia
(Lord Howe Rise ) might have slid over a stationary hotspot , forming the Lord Howe Seamount Chain .

Zealandia
Zealandia
is occasionally divided by scientists into two regions, North Zealandia
Zealandia
(or Western Province) and South Zealandia
Zealandia
(or Eastern Province), the latter of which contains most of the Median Batholith crust. These two features are separated by the Alpine Fault
Alpine Fault
and Kermadec Trench and by the wedge-shaped Hikurangi Plateau , and are moving separately to each other.

CLASSIFICATION AS A CONTINENT

The case for Zealandia
Zealandia
being a continent in its own right was argued by Nick Mortimer and Hamish Campbell in their book _Zealandia: Our continent revealed_ in 2014, citing geological and ecological evidence to support the proposal.

In 2017, a team of eleven geologists from New Zealand, New Caledonia and Australia
Australia
concluded that Zealandia
Zealandia
fulfills all the requirements to be considered a drowned continent, rather than a microcontinent or continental fragment. This was widely covered by news media. The " Saint Bathans mammal
Saint Bathans mammal
", a representative of the Miocene
Miocene
Saint Bathans Fauna . It is evidence that terrestrial mammals besides bats lived in Zealandia.

BIOGEOGRAPHY

New Caledonia
New Caledonia
lies at the northern end of the ancient continent, while New Zealand
New Zealand
rises at the plate boundary that bisects it. These land masses are two outposts of the Antarctic Flora , including Araucarias and Podocarps . At Curio Bay , logs of a fossilized forest closely related to modern Kauri
Kauri
and Norfolk Pine can be seen that grew on Zealandia
Zealandia
about 180 million years ago during the Jurassic period, before it split from Gondwana. These were buried by volcanic mud flows and gradually replaced by silica to produce the fossils now exposed by the sea.

During glacial periods, more of Zealandia
Zealandia
becomes a terrestrial rather than a marine environment. Zealandia
Zealandia
was originally thought to have no native land mammal fauna, but the discovery in 2006 of a fossil mammal jaw from the Miocene
Miocene
in the Otago
Otago
region shows otherwise.

POLITICAL DIVISIONS

Exclusive economic zone
Exclusive economic zone
of New Zealand
New Zealand
and continental shelf boundaries for much of Zealandia
Zealandia

The total land area (including inland water bodies ) of Zealandia
Zealandia
is 286,655 km2 (110,678 sq mi). Of this, New Zealand
New Zealand
comprises the majority, at 267,988 km2 (103,471 sq mi or 93%) which includes the mainland, nearby islands, and most outlying islands including the Antipodes Islands , Auckland Islands , Bounty Islands , Campbell Islands , and Chatham Islands (but not the Kermadec Islands or Macquarie Island
Island
( Australia
Australia
), which are part of the rift).

New Caledonia
New Caledonia
and the islands surrounding it comprise some 18,576 km2 (7,172 sq mi or 7%) and the remainder is made up of various territories of Australia
Australia
including Lord Howe Island
Island
Group (New South Wales ) at 56 km2 (22 sq mi or 0.02%), Norfolk Island
Island
at 35 km2 (14 sq mi or 0.01%), as well as Elizabeth and Middleton Reefs (Coral Sea Islands Territory ) with 0.25 km2 (0.097 sq mi).

POPULATION

The total human population of Zealandia
Zealandia
today is about 5 million people.

* New Zealand
New Zealand
– 4,735,600 * New Caledonia
New Caledonia
– 252,000 * Norfolk Island
Island
– 2,302 * Lord Howe Island
Island
Group – 347 * Elizabeth and Middleton Reefs – 0

REFERENCES

* ^ "Figure 8.1: New Zealand
New Zealand
in relation to the Indo-Australian and Pacific Plates". _The State of New Zealand’s Environment 1997_. 1997. Retrieved 20 April 2007. * ^ Danver, Steven L. (22 December 2010). _Popular Controversies in World History: Investigating History\'s Intriguing Questions_. ABC-CLIO. p. 187. ISBN 978-1-598-84078-0 . Zealandia
Zealandia
or Tasmantis, with its 3.5 million square km territory being larger than Greenland,... * ^ Keith Lewis; Scott D. Nodder; Lionel Carter (11 January 2007). "Zealandia: the New Zealand
New Zealand
continent". _Te Ara: The Encyclopedia of New Zealand
New Zealand
_. Retrieved 22 February 2007. * ^ _A_ _B_ _C_ Mortimer, Nick; Campbell, Hamish J.; et al. (2017). "Zealandia: Earth’s Hidden Continent". _GSA Today_. 27. doi :10.1130/GSATG321A.1 . CS1 maint: Explicit use of et al. (link ) * ^ Luyendyk, Bruce P. (April 1995). "Hypothesis for Cretaceous rifting of east Gondwana caused by subducted slab capture". _Geology_. 23 (4): 373–376. doi :10.1130/0091-7613(1995)0232.3.CO;2 . * ^ "Searching for the lost continent of Zealandia". _The Dominion Post _. 29 September 2007. Retrieved 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
Zealandia
may have sunk. * ^ Campbell, Hamish; Gerard Hutching (2007). _In Search of Ancient New Zealand_. North Shore, New Zealand: Penguin Books . pp. 166–167. ISBN 978-0-14-302088-2 . * ^ Wood, Ray; Stagpoole, Vaughan; Wright, Ian; Davy, Bryan; Barnes, Phil (2003). _New Zealand\'s Continental Shelf and UNCLOS Article 76_ (PDF). Institute of Geological and Nuclear Sciences series 56; NIWA technical report 123. Wellington, New Zealand: Institute of Geological and Nuclear Sciences Limited; National Institute of Water and Atmospheric Research. p. 16. Retrieved 22 February 2007. The continuous rifted basement structure, thickness of the crust, and lack of seafloor spreading anomalies are evidence of prolongation of the New Zealand
New Zealand
land mass to Gilbert Seamount. * ^ Mortimer, Nick; Hamish Campbell (2014). _Zealandia: Our continent revealed_. North Shore, New Zealand: Penguin Books. pp. 72ff. ISBN 978-0-14-357156-8 * ^ "Zealandia: Is there an eighth continent under New Zealand?". _BBC News_. 2017-02-17. Retrieved 2017-03-26. * ^ " Great South Basin – Questions and Answers". 11 July 2007. Retrieved 18 April 2008. * ^ "New survey published on NZ mineral deposits". 30 May 2007. Retrieved 18 April 2008. * ^ "Figure 4. Basement rocks of New Zealand". _UNCLOS Article 76: The Land mass, continental shelf, and deep ocean floor: Accretion and suturing_. Retrieved 21 April 2007. * ^ Mortimer, Nick; Hamish Campbell (2014). _Zealandia: Our continent revealed_. North Shore, New Zealand: Penguin Books . pp. 120ff. ISBN 978-0-14-357156-8 . * ^ Yarwood, V. Book
Book
review of "Zealandia: Our continent revealed", _ New Zealand
New Zealand
Geographic_, November-December 2014. Retrieved 30 July 2017. * ^ Potter, Randall (16 February 2017). "Meet Zealandia: Earth\'s latest continent". CNN. * ^ Hunt, Elle (16 February 2017). " Zealandia
Zealandia
– pieces finally falling together for continent we didn\'t know we had". The Guardian. * ^ East, Michael (16 February 2017). "Scientists discover \'Zealandia\' – a hidden continent off the coast of Australia". The Telegraph. * ^ Fossil
Fossil
forest: Features of Curio Bay/Porpoise Bay Retrieved on 6 November 2007 * ^ Campbell, Hamish; Gerard Hutching (2007). _In Search of Ancient New Zealand_. North Shore, New Zealand: Penguin Books. pp. 183–184. ISBN 978-0-14-302088-2 . * ^ http://www.stats.govt.nz/tools_and_services/population_clock.aspx

FURTHER READING

* Mortimer, N., and Campbell, H. (2014) _Zealandia: Our continent revealed_. Auckland: Penguin Books (NZ). ISBN 978-0143571568

EXTERNAL LINKS

* Zealandia
Zealandia
the New Zealand

.