Paritutu Rock

The andesite rocks of Paritutu and the nearby Sugarloaf Islands are the deeply eroded plugs of an ancient volcano that would probably have once been the size of modern Mount Taranaki. Dated at about 1.8 million years old they are the oldest in a line of volcanic centres that you can see in the ranges to the south.

As you climb up to the peak, the rocks you are holding on to are hornblende andesite that crystallised out of molten magma. This is similar to the rock which makes up the nearby Sugarloaf Islands as well as the other Taranaki volcanoes. In places during your ascent you can see that the rock has been fractured into angular pieces to form what is known as a breccia.
The top of Paritutu is a perfect viewpoint across the volcanic landscape and coastal plains of North Taranaki. The ranges to the south are the remains of former volcanoes with the Kaitake Range (dated at 500,000 years old), and the younger, higher (less eroded) Pouakai Range (250,000 years). The near perfect cone of Mount Taranaki dominates the horizon. This volcano last erupted about 250 years ago. The mountain has been built up, with repeated massive collapses, over the last 125,000 years.
The ring plains around Mount Taranaki and Pouakai are made up mostly of layers of lava, ash (tephra) and lahars. There are also thick debris avalanche deposits that spread 40km or more from the volcano during single catastrophic collapses of the mountain.
The viewpoint is a perfect place to look down on the city and the port. The power station below Paritutu uses gas from the Maui field about 40 km to the southwest.