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Kaikohe-Bay of Islands volcanic field

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Kaikohe-Bay of Islands volcanic field
Photograph of Te Ahuahu
Te Ahuahu, looking from Waimate North
Highest point
Coordinates35°20′54″S 173°50′55″E / 35.348316°S 173.848686°E / -35.348316; 173.848686
Geography
Kaikohe-Bay of Islands volcanic field is located in Northland Region
Kaikohe-Bay of Islands volcanic field
Kaikohe-Bay of Islands volcanic field
Geology
Rock age20–0.0013 Ma
Last eruption1300 to 1800 years ago

The recently active basaltic Kaikohe-Bay of Islands volcanic field in the Northland Region of New Zealand is associated geographically with an older region of extinct volcanism to its north the Wairakau Volcanic Centre, meaning eruptions in this region have occurred over the last 20 million years.[1] All the cones older than 2 million years have eroded away, leaving plateaus from Ōkaihau to Kerikeri and north to Whangaroa from the old andesite/dacite stratovolcanoes of the Wairakau Volcanic Centre and the ten million year old or more recent volcanoes in field towards the south. In the southern part of the field, around 12 small basaltic scoria cones, and a rhyolite dome erupted in the last 500,000 years around Kaikohe. The field is considered dormant, rather than extinct.[2]

Map
Map to emphasise selected recent surface volcanic features of the dormant Kaikohe volcanic field. Scoria vents (large red rectangle outlined in black) and lava fields (brown) less than a million years old are shown. More ancient volcanic deposits associated with the stratovolcanoes of the Wairakau Volcanic Centre are to the north in red and are from about 20 million years ago. These older eroded vents are shown as small red rectangles outlined in black if the map is enlarged. To do this click on the map and you will also enable mouseover of volcano feature/wikilinks.[3][4][2][5]

Tectonics

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The field is part of the eastern Northland volcanic belt which extends south to the Whangārei volcanic field near Whangārei and the south east volcanics of the Taurikura volcanic complex as found in the Hen of the Hen and Chicken Islands. In the north this belt extends towards the Three Kings Ridge.[1] As such, a large number and types of volcanics are adjacent. It is arc related to the continent-backarc transform Vening Meimesz fault zone to the east of the present Northland land mass which is the eastern boundary of the Northland Allochthon in Zealandia.[6]

List of volcanoes

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The volcanoes in the southern part of the field include:[2]

Map
Map of more detailed volcanic features of the dormant Kaikohe volcanic field allowing wider context. Clicking on the map enlarges it, and enables panning and mouseover of volcano name/wikilink and ages before present. The key to the other volcanics that are shown with panning is basalt - brown, monogenetic basalts - dark brown, undifferentiated basalts of the Tangihua Complex in Northland Allochthon - light brown, arc basalts - deep orange brown, arc ring basalts -orange brown, dacite - purple, andesite - red , basaltic andesite`- light red, rhyolite - violet , ignimbrite (lighter shades of violet), and plutonic - gray.

References

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  1. ^ a b Booden, Mathijs A.; Smith, Ian E.M.; Black, Philippa M.; Mauk, Jeffrey L. (2011). "Geochemistry of the Early Miocene volcanic succession of Northland, New Zealand, and implications for the evolution of subduction in the Southwest Pacific". Journal of Volcanology and Geothermal Research. 199 (1–2): 25–37. doi:10.1016/j.jvolgeores.2010.10.006. ISSN 0377-0273.
  2. ^ a b c Hayward, Bruce; Smith, Ian (2002). "Field Trip 7: A Taste of Northland Geology" (PDF). In Smith, Vicki; Grenfell, Hugh (eds.). Field Trip Guides, GSNZ Annual Conference "Northland 2002". Geological Society of NZ Miscellaneous Publication 112B. Retrieved 28 March 2012.
  3. ^ Mulheim, M. (1973). Volcanic geology of the Kaikohe area, Northland (Thesis).
  4. ^ Shane, Phil (2007). "Project: The evolution of basaltic volcanism in Northland in space and time Earthquake Commission Grant (project 09/U585)" (PDF). Retrieved 11 December 2022.
  5. ^ GNS Science - Geological Map of New Zealand
  6. ^ Herzer, R.H.; Davy, B.W.; Mortimer, N.; Quilty, P. G.; Chaproniere, G. C. H.; Jones, C. M.; Crawford, A. J.; Hollis, C. J. (2009). "Seismic stratigraphy and structure of the Northland Plateau and the development of the Vening Meinesz transform margin, SW Pacific Ocean". Mar Geophys Res. 30: 21–60. doi:10.1007/s11001-009-9065-1. S2CID 129934775.
  7. ^ "Kaikohe-Bay of Islands". Global Volcanism Program. Smithsonian Institution. Retrieved 28 March 2021.
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