We were then on the road to Rotorua, known for its geothermal activity. As we drove along we started to see more and more, what appeared to be, steam vents.
We stopped in at the Wai-O-Tapu Thermal Wonderland. This thermal area is part of a larger Scenic Reserve in the Taupo Volcanic Zone. The area is over 18 sq.km and is literally covered with collapsed craters, cold and boiling pools of mud, water, and steaming fumaroles. (The wonderland makes up just a small part of this)
Beneath the ground is a system of streams which are heated by magma left over from earlier eruptions. The water is so hot (temperature of up to 300C) that it absorbs minerals out of the rocks through which it passes and transports them to the surface as steam where they are ultimately absorbed into the ground. The so called “rotten egg smell” of geothermal areas is associated with “hydrogen sulphide” (H2S)
Artist’s Palette – Overflow water from the nearby spring draws with it minerals from below the surface. As the waters cool and the minerals are exposed to our atmosphere they show themselves in a variety of locations and colours depending on the water levels and wind direction.
The Primrose Terrace – The largest sinter terraces in New Zealand. The water from the nearby spring/pool dissolved silica which, as the water evaporates, is deposited as siliceous sinter. They are very fragile and have been forming for the last 700 years. (3 acres as of today)
The Champagne Pool – 65m in diameter and 62m deep. Its surface temperature is 74C and bubbles are due to carbon dioxide. The pool was formed 700 years ago by a hydrothermal eruption. Minerals contained in the water are gold, silver, mercury, sulphur, arsenic, thallium, antimony, etc and are presently depositing on the sinter ledge.
Range of colours in the area are due to different mineral elements. Green – Colloidal sulphur, ferrous salts, Orange – Antimony, Purple – Manganese oxide, White – Silica, Yellow-Primrose – Sulphur, Red-Brown – Iron Oxide, Black – Sulphur and carbon.
*Trentepohlia is the name given to the reddy-brown to bright orange colour algae seen on the vegetation in the park. Its colour is usually due to an orange pigment which hides the normally green pigment of plants known as chlorophyll.
A little more driving and we were in Rotorua. We checked into our hostel, Rock Solid Backpackers. Aptly named as it has a climbing gym under it / next to it.
We walked around town and hit “eat street” where we had some okay Thai whilst we planned the days ahead.
Until next time…