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Punakaiki -
Background Information
The
Pancake Rocks
| The Pancake Rocks were formed 30 million years ago from tiny fragments
of dead marine creatures and plants which landed on the sea bed, about two
kilometres below the surface. Immense pressure from the overlying water
caused these fragments to solidify in alternated hard and soft layers.
Gradually, seismic action lifted the limestone above the seabed. Rainwater
containing mild acid immediately went to work, with help from wind and
seawater, sculpting the bizarre shapes seen today. |
Caves
Caves are natural ěholesî in rocks. At Punakaiki, you can see caves
formed by the sea e.g. Te Ana o Matuku cave at the Fox River mouth as well
as caves formed by the dissolution of limestone rock e.g. the Cavern or the
Fox River Cave. Sea caves are formed when waves repeatedly pound against
cracks in rocks. As the cracks enlarge, a cave is formed.
Limestone caves are formed when rainwater trickling through the forest and
soil picks up carbon dioxide from the atmosphere - and more effectively from
plant roots, bacteria and fungi - creating a weak acid (carbonic acid -
H2CO3). When this weak acid comes into contact with limestone rocks (calcium
carbonate - CaCO3), the limestone is dissolved into calcium (Ca) and
bicarbonate (HCO3). The bicarbonate is soluble in water and washes away
creating underground cave passages. |
Speleothems (Stalagmites and Stalactites)
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When water carrying
dissolved limestone passes into a cave, it loses some of its carbon dioxide
gas, which means it is no longer able to hold the dissolved limestone. It
therefore deposits small crystals of limestone on to the ceiling and the
floor. These gradually build up to form stalactites and stalagmites. |
The Bush
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The Bush
Punakaiki is a plant paradise! There are hardly any frosts, over 2000 hours
of sunshine and 2000mm of rain every year. The forest is made of a variety
of broadleaf trees like kamahi, mahoe, kawakawa (there are a number at the
start of the Dolomite Point Track), wineberry, and seven finger. Originally,
podocarps, like rimu, matai and kahikatea dominated but some of these areas
have been logged in the past. As you walk in the bush, you will also notice
the array of epiphytes hanging in the trees. The Nikau palm groves are
another characteristic of this area. |
Animals
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Some of the animals
you might see at Punakaiki are dolphins, little blue penguins, Westland
black petrels, shags, terns, weta etc. Weeds and Animal Pests A whole host
of weeds line the roadsides and some of the tracks at Punakaiki. Of
particular note are: wild ginger, banana passion fruit, wandering willy and
gorse. These weeds are mainly garden escapes introduced by residents.
In terms of animal pests then the possum and the stoat are the most obvious.
Possums destroy the vegetation and stoats predate animals such as the
Westland black petrel chicks. Uncontrolled dogs are also a threat to the
little blue penguin.
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