Ōrākei Basin

Ōrākei Basin is one of the volcanoes in the Auckland volcanic field in the North Island of New Zealand. It has an explosion crater around 700 m wide, with a surrounding tuff ring. The present basin is slightly larger than the original maar crater.[1]

Ōrākei Basin
Aerial view of Ōrākei Basin
Aerial view of Ōrākei Basin
Location of Ōrākei Basin
Location of Ōrākei Basin
Ōrākei Basin
LocationAuckland, North Island
Coordinates36.867124°S 174.81308°E / -36.867124; 174.81308
Typemaar lake
Primary inflowsOrakei Creek
Basin countriesNew Zealand
Surface elevation0 m (0 ft)

Geology

View of Ōrākei Basin looking north-east

After eruption at least 83,000 years ago,[1] it became a freshwater lake that had an overflow stream in the vicinity of present Ōrākei Road bridge. As sea level rose after the end of the Last Ice Age, the lake, which by then had shallowed to a swamp, was breached by the sea and has been a tidal lagoon ever since. A tidal lagoon, it is popular for watersports.

History

A railway line (the North Island Main Trunk, branded as the Eastern Line for suburban services) runs through the north side of the basin. The railway runs along a causeway embankment which was constructed in the 1920s and created a barrier between the Ōrākei Basin and the rest of the Waitematā Harbour.[2] This allows for the basin to be kept full, even during surrounding low tides. The embankment has control gates to allow the scheduled flushing and re-filling of water in the basin.[3]

Amenities

A public walking track circles the basin.[4]

References

  1. Nemeth, Karoly; Kereszturi, Gabor; Agustín-Flores, Javier; Briggs, Roger Michael (2012). "Field Guide Monogenetic volcanism of the South Auckland and Auckland Volcanic Fields" (PDF). Retrieved 2 November 2022.
  2. Cameron, Ewen; Hayward, Bruce; Murdoch, Graeme (2008). A Field Guide to Auckland: Exploring the Region's Natural and Historical Heritage (Revised ed.). Random House New Zealand. p. 216. ISBN 978-1-86962-1513.
  3. "Ōrākei Basin flushing schedule". Auckland Council.
  4. Janssen, Peter (January 2021). Greater Auckland Walks. New Holland Publishers. p. 93. ISBN 978-1-86966-516-6. Wikidata Q118136068.
  • City of Volcanoes: A geology of Auckland - Searle, Ernest J.; revised by Mayhill, R.D.; Longman Paul, 1981. First published 1964. ISBN 0-582-71784-1.
  • Volcanoes of Auckland: The Essential Guide. Hayward, B.W., Murdoch, G., Maitland, G.; Auckland University Press, 2011.
  • Volcanoes of Auckland: A Field Guide. Hayward, B.W.; Auckland University Press, 2019, 335 pp. ISBN 0-582-71784-1.
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