Puhinui Craters
Encyclopedia
The Puhinui Craters are located in Auckland
's Puhinui Reserve and are part of New Zealand
's Auckland Volcanic Field
. They were first recognised as volcanic craters in 2011. A cluster of three small maar
craters like these is unique in the Auckland Volcanic Field. Their ages are unknown but most probably all three erupted during the same eruptive episode. They could have been associated with the eruption of nearby McLaughlins Mt but this is speculation at present.
There are three small maar craters. Each features a small oval depression on the top of their own separate tuff
cone. Soon after each eruption this depression would have been filled by a small freshwater lake. Over many years the overflows from these lakes eroded down the lowest side of each surrounding tuff ring thereby breaching the craters.There are three small maar craters, each forming a depression atop their own small tuff cone made of the erupted volcanic ash
Puhinui Pond Crater, near the reserve entrance, is currently filled with a farm pond. The crater is 200 x 150 m across and the nearly complete surrounding tuff ring rim rises 1.5–2 m above the pond.
Puhinui Arena Crater is breached on both the west and east sides. It is 250 x 150 m across and its drained and sediment-filled flat floor is 2-2.5 m below the rim of the surrounding tuff ring.
Puhinui Eroded Crater lies directly east of Arena Crater on the route of the small stream that drains the latter. Eroded Crater is breached at both west and east ends and its tuff cone partly eroded by the adjacent Puhinui Stream. It is less well-preserved than the other two craters but of similar size.
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...
's Puhinui Reserve and are part of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's Auckland Volcanic Field
Auckland Volcanic Field
The Auckland volcanic field is a monogenetic volcanic field in the North Island of New Zealand. Basaltic in nature, it underlies much of the metropolitan area of Auckland....
. They were first recognised as volcanic craters in 2011. A cluster of three small maar
Maar
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...
craters like these is unique in the Auckland Volcanic Field. Their ages are unknown but most probably all three erupted during the same eruptive episode. They could have been associated with the eruption of nearby McLaughlins Mt but this is speculation at present.
There are three small maar craters. Each features a small oval depression on the top of their own separate tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
cone. Soon after each eruption this depression would have been filled by a small freshwater lake. Over many years the overflows from these lakes eroded down the lowest side of each surrounding tuff ring thereby breaching the craters.There are three small maar craters, each forming a depression atop their own small tuff cone made of the erupted volcanic ash
Puhinui Pond Crater, near the reserve entrance, is currently filled with a farm pond. The crater is 200 x 150 m across and the nearly complete surrounding tuff ring rim rises 1.5–2 m above the pond.
Puhinui Arena Crater is breached on both the west and east sides. It is 250 x 150 m across and its drained and sediment-filled flat floor is 2-2.5 m below the rim of the surrounding tuff ring.
Puhinui Eroded Crater lies directly east of Arena Crater on the route of the small stream that drains the latter. Eroded Crater is breached at both west and east ends and its tuff cone partly eroded by the adjacent Puhinui Stream. It is less well-preserved than the other two craters but of similar size.