Rotorua, New Zealand


     Becky (my wife) and I visited the North Island of  New Zealand during the end of November, 2012.  We were there to visit relatives.  At that time we decided to explore and trek the north-eastern part of the Island.  That is where we came across the spectacular sights of the Rotorua Geothermal Region.

Geological Image of New Zealand, (Plate Movement)

     Pictured below, deep beneath New Zealand, two giant tectonic plates, the Pacific Plate and the Indo-Australian Plate, are in colossal struggle.

Image taken from a sign at Rotorua, (public domain).  It is a geological cross section of the North Island; New Zealand.

     As the Pacific Plate grinds 100 km below the surface, it creates enough friction and heat to melt itself, turning into 1,000 degrees Celsius magma.  At that temperature, magma starts rising through cracks in the plate, meeting cold ground water on the way, (Imaged above).

Image taken from a sign at Rotorua, (public domain). It is a geological map of the Rotorua area on the North Island; New Zealand.

     Pictured above, the 22-km-wide Rotorua caldera is the NW-most caldera of the Taupo volcanic zone. Rotorua is the only single-event caldera in the Taupo volcanic zone and was formed about 220,000 years ago following eruption of the >340 cu km rhyolitic Mamaku Ignimbrite.  Although caldera collapse occurred in a single event, the process was complex and involved multiple collapse blocks. The major city of Rotorua lies at the south end of the lake that fills much of the caldera. Post-collapse eruptive activity, which ceased during the Pleistocene, has been restricted to lava dome extrusion without major explosive activity. The youngest eruptive activity at Rotorua consisted of the eruption of three lava domes less than 25,000 years ago.

I’m waving above a sulfide deposit and mud pool at the Rotorua Geothermal Region in New Zealand 2012.

     Around Rotorua that turmoil finds expression as more than 1,200 geothermal features, (geysers, hot springs, mud pools, fumaroles, silica terraces, and salt deposits).

A mult-colored lake called the “Central Pool”  at Waiotapu in the Rotorua Geothermal Region on the North Island of New Zealand

     This extreme environment has attracted its own unique life-forms, (multihued lichens, mosses and specially adapted heat-tolerant plants).

Becky standing next to a hot-springs pool called the “Devil’s Ink Pots” at Waiotapu in the Rotorua Geothermal Region in New Zealand 2012.

     The area we decided to explore was the Waiotapu area.  Waiotapu is the region’s most colourful thermal park. Wai-O-Tapu means “Sacred Water” and it is easy to see why.  Pictured above and below, the Devil’s Ink Pots depict the unstable nature of the volcanic environment. Boiling pots of black mud their water levels fluctuate with the varying amounts of rainfall.  Colored an inky black by particles of crude oil and graphite brought to the surface with the escaping steam, the Devil’s Ink Pots bear resemblance to a witch’s cauldron and smell like a sickly sulphur potion.

A fumarole at the Rotorua Geothermal Region in New Zealand.

      Hot pools range in hues of turquoise blue and rich green to burnt orange and sulphuric yellow, making the steaming waters of Waiotapu a dazzling must-see.

Sulfur yellow salt in the hot-spring waters of Rotorua in New Zealand

     Becky and I experienced unique sinter terrace formations clad in primal native bush, spectacular views over mysterious craters, erupting mud pools, as well as world famous attractions, Champagne Pool and Lady Know Geyser.

Mud pool at the Rotorua Geothermal Region in New Zealand

     Pictured above, A mudpot, or mud pool, is a sort of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud. The acid and microorganisms decompose surrounding rock into clay and mud.  The mud of a mudpot takes the form of a viscous, often bubbling, slurry. As the boiling mud is often squirted over the brims of the mudpot, a sort of mini-volcano of mud starts to of 1 to 1.5 meters. Although mudpots are often called mudcrappers, true mud volcanoes are very different in nature. The mud of a mudpot is generally of white to greyish color, but is sometimes stained with reddish or pink spots from iron compounds. When the slurry is particularly colorful, the feature may be referred to as a paint pot.

New Zealands native plant symbol of a fern captured within the Hotsprings mud at Rotorua Geothermal Region.

        Pictured below, the spectacular Champagne Pool is a magnificent example of the vibrant colours caused by mineral and silicate interference. Bubbling CO2 rises from the deep green of the spring, while heavy metal sulphides precipitate at the edges to form a brilliant orange ring.   At sixty five meters in diameter and sixty two meters deep it is the largest natural spring in the area. Formed over seven hundred years ago by a hydrothermal eruption it continues to be fed from a system of underground streams.  Water entering the spring from below is up to two hundred and thirty degrees centigrade, as it rises it gradually cools to a tepid seventy four degrees where it then evaporates into the cool air above.  The high temperatures at depth encourage the transfer of minerals from the rock to the water. Gold, silver, mercury, sulphur, arsenic and thallium are all absorbed and brought to the surface where they are deposited at the edge of the spring on a sinter ledge

Champagne Pool at the Rotorua Geothermal Region

     Becky and I followed the Champagne pool down to where it spills over a waterfall of ethereal beauty and trickles over the surface of Primrose Terrace towards Bridal Veil Falls.

Primrose Terrace at the Rotorua Geothermal Region in New Zealand
Mudlakes at the Rotorua Geothermal Region in New Zealand
The Devil’s Bath at the Rotorua Geothermal Region in New Zealand

          Pictured above, the Devil’s Bath is a toxic mix of sulphur and ferrous salts that combine with the minerals from the Champagne Pool to create a day glow yellow anomaly.  The insipid color changes through yellow to green depending on the amount of reflected light and cloud cover.

The Devil’s Home at Waiotapu in the Rotorua Geothermal Region in New Zealand 2012

     Pictured above, Becky is sitting next to the Devils Home.  It is a collapsed crater where underground acid erosion has eaten away at the earth and caused it to collapse in on itself. The rough sides of the crater are tinged with a greenish hue from the cooling sulphuric volcanic vapors and ferrous salts escaping into the atmosphere.

Another view of the Central Pool at the Waiotapu in the Rotorua Geothermal Region

     Although there are no fish found in the waters of Waiotapu, due to the high level of minerals and toxic gases, there are a number of topside inhabitants that can be seen in the surrounding vegetation.

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