Mt Wellington

Maunga-a-Reipae

Mt Wellington is the largest scoria cone (volume of scoria) and the second youngest volcano in the Auckland Volcanic Field, erupting about 9000 years ago.

The Auckland Volcanic Field is comprised of monogenetic volcanoes which means it is unlikely that Mt Wellington or any of the existing volcanoes will erupt again. The next eruption will probably occur in a new location.

Formation

Mt Wellington is the most recent site of mainland activity (about 9000 years ago). Scoria and lava deposits overlie tuff deposits from early eruptions. The 100 metre scoria cone was produced from lava fountaining from 3 vents in the crater. Lava flows streamed from a number of vents to Penrose and then on to the Manukau Harbour forming almost 6km long lava flows.

Use and value

Mt Wellington is a site of archaeological importance. The terraces, food storage pits and defensive trenches which have been uncovered show that Maori used this area over a considerable period of time The mountain was named in honour of the Duke of Wellington. Its Maori name, Maungarei, is translated as 'the watchful mountain' or as 'the mountain of Reipae', a Tainui ancestor. She travelled to Northland in the form of a bird.

While the entire Mt Wellington volcanic complex is of geological interest, much of the lava flow has been modified by urban and industrial development, and consequently the primary heritage value is the remaining scoria cone that is reserved. The vast Lunn Ave quarry in the lava field to the north-west is the largest aggregate quarry in New Zealand. In 1988 it produced almost 7% of the national total aggregate. Quarrying at Mt Wellington is close to its end. Preparations for a planned new commercial, residential and recreational development are under way.

Ground water soakage through Mt Wellington's lava flows contributes to the industrial water supply at Penrose, 5 km away.

Key facts

Maori name: Maunga-a-Reipae, 'watchful mountain' or 'the mountain of Reipae'
Location: Auckland City, map reference NZMS 260: R11/750772
Height: 135m
Age: Formed about 9000 years ago
Volume lava: 160 million cubic metres (equivalent to 32,000 Olympic sized swimming pools)
Volume tuff/ash/pyroclastics: 9.2 million cubic metres (equivalent to 1,840 Olympic sized swimming pools)