Map showing Kawakawa Tephra distribution. From Vandergoes et al. 2013, Quaternary Science Reviews 74
This scrappy looking outcrop shows the deposition of Kawakawa/Oruanui tephra which comes all the way from a gargantuan eruption of Taupo volcano. The super-eruption that deposited this tephra occurred around 26,500 years ago, when over 500 cubic kilometres of magma was erupted!
White Kawakawa Tephra sitting within the brown loess. K.Amai / Victoria University of Wellington
This outcrop shows a thick layer of whitish coloured volcanic ash (Kawakawa Tephra) from the Oruanui super eruption from Taupo about 26,500 years ago. This ash fall covered much of New Zealand (see isopach map). The tephra sits within a thicker layer of orange brown loess. This material is windblown silt that was deposited over much of the Wellington landscape when vegetation was sparse during the cold climate of the last ice age.
Raodside outcrop in Karori showing Kawakawa Tephra (White layer). Photo by Cliff Atkins / VUW
Rub the tephra between your fingers and feel the texture. It is made up of very small grains of pumice (rhyolite) which is a glassy rock full of gas bubbles making it abrasive to the touch.
How thick do you think the ash layer is?Try to visualise the size of the eruption that blanketed the Wellington region with this ash, even though it occurred 300 kms away.
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Directions/Advisory
Opposite Karori Anglican Church. There should be plenty of road side car parks available along Karori road.
Beware of traffic. Do not interfere with the outcrop or plants which are on private property