Orakei Korako
Orakei Korako is a highly active geothermal area most notable for its series of fault-stepped sinter terraces, located in a valley north of Taupō on the banks of the Waikato River in the Taupō Volcanic Zone, New Zealand. It is also known as "The Hidden Valley".[1]
The New Zealand Ministry for Culture and Heritage gives a translation of "place of adornment near the white [sinter flat]" for Ōrākei Kōrako.[2]
History of the region
From earliest times the Waikato Valley near Orakei Korako was occupied by
The earliest known route from
The first proposal for power development at Orakei Korako was made in 1904, but it was not until 1955 that the scheme was finally approved. By May 1960 an earth-filled dam, rising 49 metres above the original river level, was placed and consolidated. The filling of Lake Ohakuri began on 19 January 1961 and was completed in 14 days.
Two of the world's largest
Orakei Korako today
The lowest terrace at Orakei Korako is the jade-green Emerald Terrace, the largest of its kind in New Zealand since the presumed destruction of the famed
The Emerald Terrace continues 35 metres under the lake, which was formed for
Despite the loss of so many of its thermal features under the artificial lake, Orakei Korako remains the largest geyser field in New Zealand, with up to 35 active
The three terraces above the lakeside Emerald Terrace are great fault scarps formed by an earthquake in 131 AD, around the time when Lake Taupō (a supervolcano) was last erupting. They are mostly covered in hot water algae, or cyanobacteria, which grows in temperatures between 35–59 degrees Celsius (95-138.2 degree fahrenheit), the colours dependent on the species, with green, yellow and black the most common.
At the base of the two lower terraces – named Rainbow and Cascade Terraces – are several small geysers, including the intermittently active Sapphire Geyser, and the Hochstetter Pool (named after Austrian pioneer geologist Ferdinand von Hochstetter, who visited the area in 1859), which erupted in November 1954 and played as a geyser until mid-1955, ceasing suddenly after swarms of subterranean earthquakes.
The third and largest great fault scarp in the valley is called the Golden Fleece Terrace (named Te Kapua by the Māori people, meaning "The Cloud"), which is five metres high and 40 metres long, with a beautiful white crystal-like sinter coating. At the base are numerous vents where geysers have come and gone over the years, with the most recent, Wairiri Geyser.
Atop this terrace is the Artist's Palette, a 10,000 m² silica sinter terrace covered with clear blue alkali chloride pools and irregularly erupting geysers. To one side of this topmost terrace a new geyser began to erupt in 2001, possibly the beginnings of a further terrace.
Also at Orakei Korako is the Ruatapu Cave, one of only two caves in the world known to exist in a geothermal field. The cave extends 45 metres, with a vertical drop of 23 metres, to a shallow pool of clear, sulfate-rich, warm acid water.[7] (The pool's chemical composition gives it the unique ability to clean jewellery.)
Another notable feature at Orakei Korako is the Soda Fountain, which burst into life in 1984 after a 17-year dormancy.
To the south of this feature, high atop a cliff above Lake Ohakuri, are three further geysers, Kurapai, Ellan Vannin and Benedix Washer Geysers, in an area not accessible to the public because it is too dangerous. Temperatures of 100 degrees Celsius (212 degree fahrenheit) have been recorded here just 100 to 150 mm below the ground. Of these
The Orakei Korako geothermal system now has some protection from further development,[citation needed] although the nearby Ngatamariki Geothermal Development at Tahorakuri gained resource consent in 2010 despite its possible effects on Orakei Korako.[8]
References
- ^ Bain et al. (2006) pp.293, 308
- ^ "1000 Māori place names". New Zealand Ministry for Culture and Heritage. 6 August 2019.
- ^ Gordon (1888) pp.59–60
- ISBN 9780589003739.
- S2CID 134907436.
- ^ Bunn and Nolden, Rex and Sascha (December 2016). "Te Tarata and Te Otukapuarangi: Reverse engineering Hochstetter's Lake Rotomahana Survey to map the Pink and White Terrace locations". Journal of New Zealand Studies. NS23: 37–53.
- S2CID 128638807.
- NZPA. 13 May 2010. Retrieved 1 November 2011.
- Bain, Carolyn et al. (2006) New Zealand ISBN 1-74104-535-5
- Gordon, Terence (1888) Hot Lakes, Volcanoes, and Geysers of New Zealand, with Legends Published by Dinwiddie, Walker & co., ltd.