Onepoto (volcanic crater)

Onepoto is the name of a volcanic explosion crater (or maar) on the North Shore in Auckland, New Zealand. It is a part of the Auckland volcanic field. It should not be confused with Onepoto Hill, which is a volcanic feature of the South Auckland volcanic field.

Two postcards from around 1910, showing Onepoto domain before it was reclaimed.

History

Located near the approaches to the Auckland Harbour Bridge, it was created by a series of eruptions approximately 185,000 years ago. The crater first became a freshwater lake, and later became a tidal lagoon when sea level rose to the present level 7,000 years ago after the last ice age. The crater's floor has been reclaimed, with recreational sports fields and a pond, and some parts of the tuff ring were quarried away in the 1950s to provide fill for the Northern Motorway.[1] In 1975, the crater was filled to create sports fields.[2]

Onepoto and neighbouring Tank Farm were fresh water lakes when sea levels were lower using the Last Glacial Maximum. As sea levels rose, the waters of the Waitematā Harbour breached the tuff rings of the craters, becoming tidal lagoons.[3]

See also

References
  • Volcanoes of Auckland: The Essential guide - Hayward, B.W., Murdoch, G., Maitland, G.; Auckland University Press, 2011.
  1. Onepoto and Tank Farm - City of Fire, insert magazine in The New Zealand Herald, Friday 15 February 2008.
  2. Janssen, Peter (January 2021). Greater Auckland Walks. New Holland Publishers. p. 48-49. ISBN 978-1-86966-516-6. Wikidata Q118136068.
  3. Cameron, Ewen; Hayward, Bruce; Murdoch, Graeme (2008). A Field Guide to Auckland: Exploring the Region's Natural and Historical Heritage (rev. ed.). Random House New Zealand. p. 143. ISBN 978-1-86962-1513.
  • Volcanoes of Auckland: A Field Guide. Hayward, B.W.; Auckland University Press, 2019, 335 pp. ISBN 0-582-71784-1.

36.80818°S 174.75085°E / -36.80818; 174.75085


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