Tairua Valley - Snippets of geographic and geological history

Looking up beautiful Tairua Valley towards head of valley - photo courtesy Chris Ball 2016

"The Tairua Valley is one of the most beautiful and romantic parts of the Hauraki
Peninsula.” (New Zealand Herald, 11 March 1914, Page 6) This written by a reporter visiting the area in 1914.

From the western End of this Valley up about 2,200  feet  (759 m) at the Pinnacles to sea level the eastern end. Along with the Pinnacles, other tall hills tower above the valley ( Mount Kaitarakihi )  Through the valley winds the Tairua river, with its four branches - from " the wires" near the headwaters of the Tairua, there is a plateau at about 1500 ft.

Looking towards the Pinnacles - left side top of photo - courtesy Chris Ball 2012

The Tairua valley, borne out of volcanic origins of millions of years ago, has many rugged steep hills surrounding the outer edge of the valley. From many points within the valley, can be seen a maze of low peaks and rolling ridges spread out in all directions - representing the dissected volcanic mass from the days of intense volcanic activity and lava flow.

low peaks born of volcanic activity - photo courtesy Chris Ball 2012

Rhyolite and andesite deposits are reminders of the volcanic  activity throughout the valley:-The low peak as viewed on the Woody Hill track lower Tairua valley as in the above photo. 

The rhyolitic dome  at the  harbour entrance to Tairua known as Paku. The development of  "Island"  which Homer and Moore wrote in Vanishing Volcanoes , began  7 or 8 million years ago ( Homer & Moore,p64)

Paku Island - photo 1950's unknown 

Paku " Island " is a dome within a dome. From the seaward side, can be seen the steep rhyolite eroded by the sea. 

                           View showing the twin peaks of Paku exposed to the sea - photo courtesy Chris Ball 2014

On the Southern side of the valley at the Tairua harbour mouth ( known in 2021  as Tairua Bar) and ocean lies Pauanui and  what is known as South Beach Pauanui. Beyond South Beach on the forested hills between Pauanui and Ohui lies 

a huge rhyolite dome, said to be formed 7 to 8 million years ago ( long, long ago).

                                      Pauanui to Ohui - photo courtesy Chris Ball  2015

Several parts of the dome cooled slowly, the outcome being the  spectacular columnar jointing, particularly at low tide, seen in 2021.

   Spectacular columnar jointing South Beach Pauanui photo courtesy Chris Ball 2012 - above, below 

From many points and the three settlements - Hikuai, Pauanui, Tairua, in the Tairua valley can be see to the Western side, towering over all - the Pinnacles. In all the valley is a spectacular reminder of part of our past New Zealand history with its rhyolite and andesite volcanic remains of long ago. 

                                  Towards the Pinnacles - photo courtesy Chris Ball 2014

Reference Source : 

• Bell, J. M. (1914). The Wilds of Maoriland . London: MacMillan and Co Ltd.
• by Bell, James Mackintosh,; Fraser, Colin; New Zealand. Geological Survey BranchThe geology of the Waihi-Tairua subdivision, Hauraki division Wellington, [N.Z.] : by authority John Mackay, Govt. Printer 1912
• Moore , P Homer, L. ,. 1992). Vanishing Volcanoes: A guide to the landforms and rock formations of Coromandel Penisula. Wellington: Landscape Publications.
• REPORT ON THE GEOLOGY OF THE CAPE COLVILLE PENINSULA, AUCKLAND. BY ALEXANDER McKAY, F.G.S., HON. M., N.Z. INST., GOVERNMENT GEOLOGIST.Appendix to the Journals of the House of Representatives, 1897 Session II, C-09
• C. J. Adams , I. J. Graham , D. Seward , D. N. B. Skinner , C. J. Adams , D.N. B. Skinner & P. R. Moore (1994) Geochronological and geochemical evolution of late Cenozoic volcanism in the Coromandel Peninsula, New Zealand, New Zealand Journal of Geology and Geophysics, 37:3, 359-379, https://doi.org/10.1080/00288306.1994.9514626
•  Barbara Malengreau , David Skinner , Chris Bromley & Philippa Black (2000) Geophysical characterisation of large silicic volcanic structures in the Coromandel Peninsula, New Zealand, New Zealand Journal of Geology and Geophysics, 43:2, 171 186, https://doi.org/10.1080/00288306.2000.9514879
• by B.W. Hayward*, P.R. Moore*t, D.A.B. MacFarlan GEOLOGY OF SHOE ISLAND AND THE SLIPPER ISLAND GROUP TANE 20 1974
• (New Zealand Herald, 11 March 1914, Page 6