Shipwreck Bay, Ahipara

The rocks here at Shipwreck Bay reveal the power of Earth's tectonic forces. Originally formed by plutonic, volcanic, and sedimentary processes deep under an ancient sea in Late Cretaceous to Paleocene time, they were then transported hundreds of kilometres and emplaced here at Ahipara as part of the upper thrust sheet of the Northland Allochthon. We call this mass of rock the "Ahipara Massif".

In the shore platform you can see a good range of rock types within the Tangihua Complex: highly indurated thin-bedded
mudstones, cherts and tuffs are interbedded with and in fault contact with pillow lavas and massive flows. Inoceramus fragments (a now extinct family of marine bivalve) have been found in some of the sediments. In Shipwreck Bay a gabbroic intrusive complex is exposed.

Can you see the distinctive round shapes of pillow lavas? They show where molten rock flowed out of the Earth and onto an ancient sea floor! Think about the types of animals that would have been swimming in the deep ocean that would have existed above these rocks all those millions of years ago. Think of the immense tectonic forces that would have moved these rocks so many hundreds of kilometres from where they originally formed.