Volcanism of New Zealand

Source: Wikipedia, the free encyclopedia.

Main vent of Whakaari / White Island in 2000

The volcanism of New Zealand has been responsible for many of the country's geographical features, especially in the North Island and the country's outlying islands.

While the land's

Pacific Ring of Fire, and particularly the subduction
of the Pacific Plate under the Indo-Australian Plate.

New Zealand's rocks record examples of almost every kind of volcanism observed on Earth, including some of the world's largest eruptions in geologically recent times.

None of the South Island's volcanoes are active.

Map
Map of selected surface volcanic features in the northern
Northland Allochthon,
  arc basalts,  arc ring basalts,
  dacite,
  andesite (shades of red),   basaltic andesite,
  rhyolite, (ignimbrite
is lighter shades of violet),
and   plutonic. White shading is selected caldera features.
USGS
map of New Zealand's major volcanoes

Major eruptions

The scalloped bays indenting Lake Taupō's northern and western coasts are typical of large volcanic caldera margins. The caldera they surround was formed during the huge Oruanui eruption.

New Zealand has been the site of many large explosive eruptions during the last two million years, including several of

Reporoa, Rotorua, and Haroharo calderas
.

Two relatively recent eruptions from the

ash fall, with even an 18 cm (7 inch) ash layer left on the Chatham Islands, 1,000 km (620 mi) away. Later erosion and sedimentation had long-lasting effects on the landscape, causing the Waikato River to shift from the Hauraki Plains to its current course through the Waikato to the Tasman Sea.[4] New Zealand's largest lake, Lake Taupō, fills the caldera
formed in this eruption.

Taupō's most recent major

ash turned the sky red over Rome and China.[7]

Te Wairoa, and claiming the lives of perhaps 120 people.[9] Approximately 2 km3 of tephra was erupted (VEI 5).[8]

Part of the 17-kilometre (11 mi) long rift created in Mount Tarawera's 1886 eruption

Hazards

As well as the direct effects of explosions,

ashfall
, and other far field effects.

Ruapehu's crater lake, source of the deadly 1953 lahar

For instance, the Tangiwai disaster occurred on 24 December 1953 when the Tangiwai railway bridge across the Whangaehu River collapsed from a lahar in full flood, just before an express train was about to cross it. The train could not stop in time, and 151 people died. This was ultimately caused by Ruapehu's 1945 eruption, which had emptied the crater lake and dammed the outlet with tephra.

An eruption of the Whakaari / White Island stratovolcano occurred on 8 December 2019 while there was a group of 47 visitors on the island. Twenty-two people died, either in the explosion or from injuries sustained, including two whose bodies were never found and were later declared dead. A further 25 people suffered injuries, with the majority needing intensive care for severe burns.[10]

Effects can be widespread even for eruptions of only moderate size. Ash plumes from Ruapehu's 1996 eruption forced the closure of eleven airports, including

Auckland International Airport.[11]

Insurance against volcanic damage (along with other natural disasters) is provided by the country's Earthquake Commission.

Cultural references

The

Tongariro and Pihanga. It holds that the two first-named volcanoes competed for the love of the beautiful Pihanga and, after Tongariro succeeded, the defeated Taranaki moved to its lonely location near New Plymouth
.

The young stratovolcano Ngauruhoe, named after the slave who legend says died on its summit

Another legend recounts the exploits of Ngātoro-i-rangi, a tohunga (priest) who arrived from the ancestral Māori homeland, Hawaiki, on the Arawa waka (canoe). Travelling inland and then looking southward from Lake Taupō, he decided to climb the mountains he saw there. He reached and began to climb the first mountain along with his slave Ngāuruhoe, who had been travelling with him, and named the mountain Tongariro (the name literally means 'looking south'), whereupon the two were overcome by a blizzard carried by the cold south wind. Near death, Ngātoro-i-rangi called back to his two sisters, Kuiwai and Haungaroa, who had also come from Hawaiki but remained on Whakaari / White Island, to send him sacred fire, which they had brought from Hawaiki. This they did, sending the fire in the form of two taniwha (powerful spirits) named Te Pupu and Te Haeata by a subterranean passage to the top of Tongariro. The tracks of these two taniwha formed the line of geothermal fire that extends from the Pacific Ocean and beneath the Taupō Volcanic Zone, and is seen in the many volcanoes and hot springs extending from Whakaari to Tokaanu and up to the Tongariro massif. The fire arrived just in time to save Ngātoro-i-rangi from freezing to death, but Ngāuruhoe had already died by the time Ngātoro-i-rangi turned to give him the fire. For this reason the hole through which the fire ascended, the active cone of Tongariro, is now called Ngauruhoe.

Eruptions in the North Island, such as the Kaharoa eruption of Mt Tarawera in 1314, have been used to help determine the approximate date of arrival of the early Polynesian colonists to about 1280. Fossilized footprints of perhaps second- or third-generation Polynesian colonists have been found in volcanic ash on islands in the Hauraki Gulf.

Geology

Main article: North Island surface volcanism
Main article: South Island surface volcanism

Please see the main articles above because as already mentioned almost every kind of volcanism observed on Earth is found in New Zealand. For historic intrusive volcanism please see the section on older volcanism below. There is good evidence for continued intrusive volcanism activity in the central North Island.

pluton of the order of 550,000 years old has been dated from drill cores there.[14]

Volcanic areas

While there are remnants of volcanic activity throughout most of New Zealand, there are several areas where they are more obvious, and somewhere activity continues. Since Taranaki's last activity in 1854, all eruptions have been in the Taupō Volcanic Zone or the Kermadec Arc.[15]

Location volcanic eruptions North Island New Zealand
Significant recent (last 2000 years) volcanic eruptions (red) and hydrothermal eruptions (blue) in North Island of New Zealand

Kermadec Arc

The Kermadec Islands are an active volcanic island arc stretching north-northeast from New Zealand's North Island towards Tonga. While only a few volcanoes in the arc are tall enough to form islands, it includes about 30 sizeable submarine volcanoes with many in the South Kermadec Ridge Seamounts at the New Zealand end of the chain. The largest island, Raoul Island, produced a large eruption around 2200 years ago with a VEI of 6.[16] Its activity has continued intermittently since, with its latest eruption occurring in 2006.[17]

Northland

The Northland region contains two recently active volcanic fields, one centered around Whangarei,[18] and the other is the Kaikohe-Bay of Islands volcanic field.[19] The latest activity in the Kaikohe-Bay of Islands field, around 1300 to 1800 years ago, created four scoria cones at Te Puke (near Paihia).[19]

volcanic neck[20]
in the western Northland volcanic arc

Earlier, during the

Waipoua forest, and the Waitākere Ranges
.

Auckland volcanic field

Rangitoto Island, the gently sloping shield volcano on the horizon, is an iconic landmark of Auckland.
Main article: Auckland volcanic field

The

dormant, the field is likely to erupt again within the next "hundreds to thousands of years" (based on past events), a short timeframe in geologic terms.[24] Auckland's residents, however, face more danger from volcanoes farther south.[24]

Auckland's volcanoes are believed to be the latest product of an unusual magma source related to local tectonics which is not a classic hot spot, as the earlier volcanic fields are to the south, the opposite expected from movement of the Australian Plate over a stationary mantle plume source.[25]

Waikato and South Auckland

Hochstetter's 1859 geological map of the southern part of the then Auckland Province showing volcanic features of Waikato and South Auckland.

Three volcanic fields erupted between 2.7 and 0.5 million years ago, migrating northwards from Mount Pirongia to the Bombay Hills. The earliest of these fields formed the Alexandra Volcanics[26] which is distinguished by large arc volcano tholeiitic cones but did have associated Okete Volcanics which were traditionally more akaline and oxidised and were in the monogenetic volcanic field pattern seen in the later fields. The distinction between the Alexandra and Okete volcanics is not necessarily clear cut and is still being studied. Alexandra Volcanic Group rocks (mostly basalt) cover about 450 km2 amounting to 55 km3 from at least 40 vents. Mount Pirongia and Mount Karioi are part of the main lineament in the group.[27] The later fields are the smallest Ngatutura Volcanics which comprises about 16 volcanoes south of Port Waikato on the west coast and the South Auckland volcanic field with over 80 volcanoes.[28] The magma body that created the Auckland volcanic field is considered to have been related to these outpourings also. Unlike typical hot spots such as the one underlying Hawaii, it does not seem to have stayed still, but instead is migrating northward at a faster pace than the surrounding Indo-Australian Plate. Its motion has been explained as the tip of a propagating crack produced by the twisting of the North Island's crust.[29][25]

Coromandel Volcanic Zone

Main article: Coromandel Volcanic Zone
Cathedral Cove, carved in tuff[30] deposited by a pyroclastic flow
about 8 million years ago

The extinct

Kaimai Ranges in the south. Activity began in the north around 18 million years ago, and was primarily andesitic until around 9–10 million years ago, when it changed to a bimodal basaltic/rhyolitic pattern. Eruptive centres gradually migrated southward,[31] where they transitioned into early activity in the Taupō Volcanic Zone. Later activity in the CVZ and its interface with the Taupō Volcanic Zone is obscured by subsequent events and is not fully understood, but continued in the south until perhaps 1.5 million years ago in the Tauranga Volcanic Centre.[32] Together with the extinct undersea Colville Ridge, the CVZ formed a precursor to the modern Taupō Volcanic Zone and Kermadec Ridge.[33]

Mayor Island / Tūhua

Main article: Mayor Island / Tūhua

peralkaline shield volcano with a caldera partly formed in a large eruption some 7000 years ago. It has exhibited many eruptive styles, and its last eruption may have occurred only 500–1000 years ago.[34]
The island's Maori name, Tuhua, refers to the obsidian they found on the island and prized for its sharp cutting edge.

Taupō Volcanic Zone

Main article: Taupō Volcanic Zone
Lady Knox Geyser, in the Waiotapu geothermal area

About 350 kilometres long by 50 kilometres wide, the

Reporoa, and Rotorua calderas, the Okataina Volcanic Complex (including Mount Tarawera) and 85 kilometres beyond Whakaari / White Island to the submarine Whakatāne Seamount. The TVZ also contains numerous smaller volcanoes, along with geysers and geothermal areas. Volcanic eruptions began here around two million years ago, with silicic eruptions starting around 1.55 million years ago, as activity shifted southeast from the Coromandel Volcanic Zone.[32]

Taranaki

Mount Taranaki, with Fanthams Peak on the left

Volcanism in the Taranaki region has migrated southeastward during the last two million years. Beginning in the Sugar Loaf Islands, near New Plymouth, activity then shifted to Kaitake (580,000 years ago) and Pouakai (230,000 years ago) before creating the large stratovolcano called Mount Taranaki, (former name Mount Egmont), which last erupted in 1854, and its satellite vent, Fanthams Peak.[37] This southeastward migration is the continuation of the 25 million year activity of the Northland-Mohakatino Volcanic Belt that extends mainly under the present Tasman Sea from the west of Northland down to Mount Taranaki.[23]

Chatham Islands

The higher portions of the Chatham Islands are formed from volcanic rock that is up to 81 million years old, although lava flows on the northern shore of Chatham Island date back only about five million years.[38]

Banks Peninsula

Main article: Banks Peninsula Volcano
The mountainous terrain of Banks Peninsula contrasts with the nearby plains.

Lyttelton and Akaroa Harbours. The portion of crater rim lying between Lyttelton Harbour and Christchurch city forms the Port Hills
.

Oamaru

Main article: Waiareka-Deborah volcanic field

Small sub-alkaline basalt to basaltic andesite Surtseyan volcanoes on the submerged continental shelf formed what was historically termed the Waiareka-Deborah volcanic group and now called the Waiareka-Deborah volcanic field in the area around Oamaru around 35 to 30 million years ago.[39][40] A monogenetic volcanic field of more alkaline composition eruptives, with stronger surface features, as they are younger, extends north of Dunedin overlapping the southern Waiareka-Deborah volcanic field, and these volcanoes have now been characterised to be part of the Dunedin volcanic group.[41]

Southern Alps

The Alpine Dyke Swarm of volcanic intusion took place about 25 million years ago and is located near Lake Wānaka in the Southern Alps.[42]

Dunedin

Main article: Dunedin volcanic group

The Dunedin Volcano formed during the Miocene, beginning with basaltic eruptions on the Otago Peninsula, is the largest volcano in the large Dunedin volcanic group.[41] Large central-vent structures formed, and then large domes, with seawater interacting explosively with erupting submarine magma.[43]

Antipodes Island

Solander Islands

The Solander Islands, a small chain of uninhabited islets close to the western end of the Foveaux Strait, are the emergent portions of a large extinct andesitic volcano that last erupted around 50,000 to 150,000 years ago.[44] Caused by the subduction of the Australian Plate beneath the Pacific Plate, it is the only volcano associated with this subduction zone that protrudes above the sea.[45][46]

Subantarctic islands

The majority of

Antipodes Island.[38] These are mainly Miocene
intraplate volcanoes with ages decreasing towards the northeast, although Antipodes Island may have been active during the last 20,000 years.

Older volcanism

The summit of Tapuae-o-Uenuku comprises the uplifted and eroded foundations of an old volcano

Older remnants of volcanism are also found in several places around New Zealand. These were generally formed either when New Zealand still formed part of the

microcontinent
of Zealandia that currently emerges above the sea.)

A band of granitic intrusions covering over 10,000 km2, the Median Batholith, stretches from

West Coast and Nelson after interruption by the Alpine Fault. This was produced between 375 and 105 million years ago in the course of subduction-related volcanism in a long mountain range along the Gondwanan coast somewhat like today's Andes. Two more batholiths
, the Karamea-Paparoa and Hohonu Batholiths, are also found on the West Coast.

Zealandia

Basaltic lava flows,

Canterbury, including at the summit of Tapuae-o-Uenuku, the country's highest mountain outside the Southern Alps.[47] The Mount Somers volcanics that erupted from 100 to 80 million years ago extend to Banks Peninsula
but are mostly buried there by more recent volcanism.

Rhyolitic ignimbrite

Kakanui Mountains that were originally dated in the range 107 to 101 million years ago[49] are now both dated to 112 ± 0.2 million years ago and so likely come from a large singe event.[50]

The Hikurangi Plateau is an oceanic plateau on the Pacific Plate that attached to the Chatham Ridge after being partially subducted under it, and is now subducting under the North Island. It likely formed in one of the world's largest volcanic outpourings, the greater Ontong Java event.

Ophiolites, volcanic deposits from the ocean floor, have been incorporated into the continental basement of New Zealand in the Dun Mountain Ophiolite Belt, found at both ends of the South Island, and in Northland.

See also

Bubbling
mud pool in the Taupō Volcanic Zone

Notes

  1. ^ Heather Catchpole. Islands of fire Archived 23 February 2010 at the Wayback Machine, Cosmos Magazine.
  2. doi:10.1016/S0377-0273(01)00239-6
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  3. doi:10.1093/petrology/egi066
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  4. doi:10.1080/00288306.2004.9515074
    .
  5. ^
    doi:10.1029/2021GC009803
    .
  6. ^ "Taupo – Eruptive History". Global Volcanism Program. Smithsonian Institution. Retrieved 16 March 2008.
  7. S2CID 4309536
    .
  8. ^ a b "Okataina: Eruptive History". Global Volcanism Program. Smithsonian Institution.
  9. ^ Dench, p 114.
  10. ^ "New Zealand volcano: Divers deployed to find last two missing bodies". 13 December 2019. Archived from the original on 13 December 2019. Retrieved 13 December 2019.
  11. ^ Mass aircraft grounding possible in NZ too scientists say Archived 22 May 2010 at the Wayback Machine, media release, GNS Science, 19 April 2010.
  12. doi:10.1130/B31657.1
    .
  13. ISSN 2296-6463
    .
  14. ISSN 0377-0273
    .
  15. ^ Volcanoes of New Zealand to Fiji, Global Volcanism Program, Smithsonian Institution.
  16. ^ "Smithsonian Global Volcanic Program:Raoul Island".
  17. ^ "Raoul Island". Global Volcanism Program. Smithsonian Institution.
  18. ^ "Whangarei Volcanic Field". Global Volcanism Program. Smithsonian Institution.
  19. ^ a b "Kaikohe-Bay of Islands". Global Volcanism Program. Smithsonian Institution.
  20. ISBN 1-86962-014-3
    .
  21. S2CID 128957126. Archived from the original
    on 25 May 2010. Retrieved 20 April 2010.
  22. ISBN 9780473395964
    . Retrieved 20 February 2022.
  23. ^
    S2CID 221380777
    .
  24. ^ a b Beca Carter Hollings & Ferner (2002). Contingency Plan for the Auckland volcanic field, Auckland Regional Council Technical Publication 165. Accessed 12 May 2008.
  25. ^ a b Nemeth, Karoly; Kereszturi, Gabor; Agustín-Flores, Javier; Briggs, Roger Michael (2012). "Field Guide Monogenetic volcanism of the South Auckland and Auckland Volcanic Fields". Retrieved 2 November 2022.
  26. S2CID 129834459
    .
  27. ISBN 0-478-08837-X
  28. hdl:10289/5260
    .
  29. ISBN 1-86950-296-5
    .
  30. ^ Hayward, B. (2008). Protecting NZ's Heritage Natural Arches, Geological Society of New Zealand Newsletter 145 (March), 23.
  31. doi:10.1080/00288306.1994.9514626
    .
  32. ^
    doi:10.1080/00288306.2005.9515126
    .
  33. doi:10.1016/S0377-0273(03)00382-2
    .
  34. ^ "Mayor Island". Global Volcanism Program. Smithsonian Institution.
  35. ^ Karl D. Spinks, J.W. Cole, & G.S. Leonard (2004). Caldera Volcanism in the Taupō Volcanic Zone. In: Manville, V.R. (ed.) Geological Society of New Zealand/New Zealand Geophysical Society/26th New Zealand Geothermal Workshop, 6–9 December 2004 , Taupo: field trip guides. Geological Society of New Zealand miscellaneous publication 117B.
  36. ^ Volcanology highlights, Volcanoes of New Zealand to Fiji, Global Volcanism Program, Smithsonian Institution.
  37. doi:10.1016/S0377-0273(96)00074-1
    .
  38. ^ a b K. S. Panter, J. Blusztajn, S. R. Hart, P. R. Kyle, R. Esser, W. C. McIntosh (2006). The Origin of HIMU in the SW Pacific: Evidence from Intraplate Volcanism in Southern New Zealand and Subantarctic Islands
  39. ^ Simone Hicks, PhD proposal: Ecological and sedimentological evolution of the volcanically active Oligocene continental shelf, east Otago, New Zealand, Geology Department, University of Otago. Retrieved 19 April 2010.
  40. S2CID 129657592
    .
  41. ^
    S2CID 212937447
    .
  42. S2CID 210266079
    .
  43. ^ ""Eruptions and deposition of volcaniclastic rocks in the Dunedin Volcanic Complex, Otago Peninsula, New Zealand", Ulrike Martin". Archived from the original on 8 June 2011. Retrieved 18 April 2010.
  44. doi:10.1086/671397
    .
  45. ^ Keith Lewis, Scott D. Nodder and Lionel Carter. 'Sea floor geology – Solander Island', Te Ara – the Encyclopedia of New Zealand. Updated 2 March 2009. Accessed 18 April 2010.
  46. ISSN 0377-0273
    .
  47. doi:10.1080/00288306.1994.9514620
    .
  48. doi:10.1080/00288306.1959.10417656
    .
  49. doi:10.1080/00288306.1988.10422144
    .
  50. S2CID 128898123
    .

References

External links
caldera lake
.
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