Red Rocks

There are three types of reddish rocks exposed at this location: 1. There are pinkish-red cherts of Permian age which are amongst the oldest rocks of the North Island. They are dominated by very fine grained silica (quartz) derived from the skeletal remians of millions of minute single celled animals called radiolarians. These were part of the plankton that floated in the seas adjacent to Gondwana more than 250 million years ago. These are conspicuous because of their contorted layering. 2. There are also brownish-red basalt lavas with distinctive pillow shapes that show that they were erupted underwater. 3. The most common red rock here is brick-red argillite (mudstone). All these red colours came after the rocks were deposited and are due to the presence of iron oxide minerals. The iron came primarily from the basalt lavas which caused this local effect. There are also green and dove-grey coloured argillites in the area. To either side of Red Rocks point there is the more usual grey coloured greywacke (sandstone and siltstone) that is widespread around Wellington's coast often with vertically tilted layering.

Have a look for the different rocks types: chert, basalt, argillite and greywacke and see if you can tell them apart. Look around to see if they extend over a wider area. Occasionally it is possible to find tube fossils in the greywacke if you keep a sharp eye out!
Triassic microfossils have been found in concretions within the argillite, and Permian microfossils have been found in the chert. It is thought that the lavas post-date the chert and pre-date the argillite.