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Accessibility: EASY
WHAT'S HERE?
Taurikura Bay natural jetty
Best example of a natural jetty in New Zealand.
LEARN ABOUT IT
Taurikura Bay natural jetty
The Taurikura Bay natural jetty is an andesite dike, which was a sheet of molten magma - part of the plumbing beneath the Whangarei Heads Volcano when it was erupting 20-17 million years ago. After the magma supply to the surface waned the magma in this feeder sheet cooled and solidified with cooling joints oriented horizontally - perpendicular to the cooling surface on either side of the sheet.
Here at Taurikura Bay we see where the sheet of magma intruded cream-coloured muddy limestone beneath the volcano. The heat of the magma baked the immediately surrounding limestone into a 50 cm wide black to dark-grey zone right next to the contact.
After the volcano above became extinct, natural erosion set to work and over millions of years has removed most of the volcano and eroded down into rocks beneath the volcano like here at Taurikura Bay. The muddy limestone is softer than the hard andesite dike and has eroded down lower leaving the dike standing up above the shore platform forming a natural jetty that sticks out into the intertidal zone and can be used as a wharf when the tide is part way in.
Here at Taurikura Bay we see where the sheet of magma intruded cream-coloured muddy limestone beneath the volcano. The heat of the magma baked the immediately surrounding limestone into a 50 cm wide black to dark-grey zone right next to the contact.
After the volcano above became extinct, natural erosion set to work and over millions of years has removed most of the volcano and eroded down into rocks beneath the volcano like here at Taurikura Bay. The muddy limestone is softer than the hard andesite dike and has eroded down lower leaving the dike standing up above the shore platform forming a natural jetty that sticks out into the intertidal zone and can be used as a wharf when the tide is part way in.
HAVE A LOOK!
Taurikura Bay natural jetty from roadside
If the tide is far enough out, see how far you can walk out along the long straight dike.
Can you see the baked zone in the cream limestone alongside the dike that intruded into it?
Why are the cooling joints in the dike horizontal?
Imagine being here 20-17 million years ago, what would it have been like?
Can you see the baked zone in the cream limestone alongside the dike that intruded into it?
Why are the cooling joints in the dike horizontal?
Imagine being here 20-17 million years ago, what would it have been like?
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Directions/Advisory
Park at Taurikura Bay parking area next to toilet block on Whangarei Heads Rd. Walk 200 m east further alongside the road to junction with Ody Rd. Find an easy way down to the shore opposite the junction.
Be careful of traffic on Whangarei Heads Rd as you walk alongside it and cross it. The low bank down to the shore can be a little slippery so be careful. Foreshore rocks may be a little slippery and rock oyster shells sharp.
Google Directions
Accessibility:
EASY
Best seen at mid to low tide. The natural jetty is under water at high tide.
You can view the jetty from the grass verge of the road or fairly easily clamber down to the shore a few metres below to inspect the jetty, its contacts and maybe walk along it.
Features
Volcanic
Landform
Geological Age
Early Miocene. 20-17 million years old.
Zealandia Evolution Sequence
Waka Supergroup (Flooding): 35 – 25 million years ago
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