Monday, 30 July 2012

Geothermal wonderland

When we originally visited Rotorua on our first trip to New Zealand, we were limited to the attractions that we could see because we didn't have our own transport and also by a lack of funds. This time round we're able to explore further outside of Rotorua even if we don't have all the money we need to see everything! However, this isn't necessarily a problem as it's quite a good thing that we're being more selective as the admissions to a lot of sights such as the Hell's Gate (Tikitere) Thermal Area, Waumangu Volcanic Valley and Te Wairoa (or the Buried Village) can cost from $30 each and we've only got so much money and time to spend in the region.

Also competing for your hard-earned dollars are various Māori "cultural experiences and performances", which to be honest feel a bit contrived in the sense that the Māori groups in Rotorua are cashing in on their heritage more than anywhere we've been to on the North Island. Having already been to Te Whakarewarewa Thermal Reserve and Te Puia we decided just to try a different thermal area, Wai-O-Tapu, as it has some of the most unique and spectacular volcanic wonders in the region, especially as the area is associated with volcanic activity dating back about 160,000 years.

Waiotapu, which means "sacred waters" in Māori, is located 27km south of Rotoua, on the Thermal Explorer Highway (State Highway 5). It's an geothermal area at the southern end of the Okataina Volcanic Centre, on the edge of the largest volcanic caldera (depression), just north of the Reporoa caldera in the Taupō Volcanic Zone. Wai-O-Tapu is considered to be one of New Zealand’s most colourful and diverse geothermal attractions, as it is set within a natural bush setting. The barren landscapes give you an impression that only the hardiest of plant life can grow here.

The harsh landscape of Wai-O-Tapu reserve

Satellite image of the Wai-O-Tapu thermal area

Photo courtesy of Google Maps ©2012 Google

Starting off at the visitor centre, the first thermal attraction to see at Wai-O-Tapu was actually in a separate area towards the Lady Knox Geyser, which was a short drive back towards the way out. The geyser is named after Lady Constance Knox, the daughter of the then 15th Governer of New Zealand, Uchter Knox.

Lizzie by Lady Knox before the big eruption 

The spout is made of rocks placed around the base of the spring to enhance the eruption, by the inmates from a nearby prison who first discovered the geyser in 1901. Over the years silica from the constant eruptions has built up to give a white cone-shaped appearance. Below the geyser are two chambers which hold 26,000 litres of water. At approx. 10.15am everyday a staff member pours a packet of surfactant into the vent so the geyser performs on cue. After about 5 mins, the surfactant eventually changes the surface tension of the two chambers, which releases the pressure of the geyser sending the water between 10 - 20 metres into the air during the initial eruption. The whole event seemed tad artificial especially since we've visited Old Faithful Geyser in Yellowstone National Park (home to half of the world's total number of geysers in its nine geyser basins) and waited patiently for Old Faithful to erupt, but I can understand if people want to see Lady Knox go off consistently as the natural cycle of the geyser is between 24 - 72 hours!

The guide in the following video explains the whole process of geyser in more detail:

Thar she blows!

Once we were finished at the Lady Knox Geyser we headed back to the visitor centre, to begin the walk round the grounds of Wai-O-Tapu. The first of the sights within the geothermal area were the Weather Pool and a series of collapsed craters. Some of the craters are up to 50 metres in diameter and 20 metres deep. Several of the craters contain hot water springs and most have sulphur deposits formed by volcanic gases. The most recent crater to be formed was the Thunder Crater, which collapsed in 1968.

Looking into the depths of the Thunder Crater

The bubbling acidic spring of the Thunder Crater

Down by the Devils-Ink Pots (a seris of bubbling mud pools of crude oil and graphite) we spotted the cat we met at the visitor centre and imaginatively named "Geothermal Cat"! He didn't have a care in the world as he was wondering through all hissing and rumbling silica mounds looking for a warm place to sit on!

Me with Geothermal Cat at the visitor's centre

With so many warm spots to pick, Geothermal Cat is spoilt for choice

Moving onto the Artist's Palette there was a lookout where you could look down on this pool where water overflowing from the Champagne Pool leaves mineral deposits in a variety of bold colours around the pool. As you walk down to the sinter terraces, there's a boardwalk which skirts the Artist's Palette on one side and on otherside the Primrose Terrace - the largest actively formed sinter terraces in New Zealand.

The Artisit's Palette boardwalk and Primrose Terrace in the background

The sulphur rich deposits of the Artist's Palette

The Primrose Terrace covers an area of approx. 3 acres

This fragile terrace has been formed over the last 700 years

The wide range of colours seen throughout the reserve are due to different mineral elements with the following colours consisting of:
  • Green - Colloidal sulphur/ ferrous salts
  • Orange - Antimony
  • White - Silica
  • Yellow - Sulphur
  • Red/ brown - Iron oxide
  • Black - Sulphur and carbon
The reddish-brown colour on the vegetation is known as Trentepohlia

Next was the multi-hued Champagne Pool, which is one of the most unique springs in the world. Formed by a hydrothermal eruption 700 years ago, it's 65 metres in diameter and 62 metres deep. The surface temperature of the bottle-green water fringed by an orange ledge is 74°C and contains numerous minerals such as gold, silver, mercury, sulphur, arsenic, thalliumm, antimony, amongst others, with bubbles of carbon dioxide breaking at the surface. The water discharged from the Champagne Pool flows across a sinter-encrusted flat, with a range of colours caused by mineral precipitation and microorganisms.

The Champagne Pool is somewhere in the steam behind Lizzie

The orange hue is caused by orpiment and realgar - sulfides of arsenic

Thermophillic microorganisms live within the edge of the pool

Walking between the Wai-O-Tapu Geyser and the Alum Cliffs there were several fantail birds (Pīwakawaka) flying around and chirping as we walked passed. Although, we've seen them quite a few times in the forests since we've been here, I've never seen so many flitting around from perch to perch in such a desolate place - it was almost like they thrived in the harsh environment. The fantails are one of our favourite birds in NZ as they're full of character, displaying their tails by constantly opening and closing them, and the noises they make remind me of a squeaky dog toy!

View towards the Wai-O-Tapu Geyser and Alum Cliffs

Pīwakawaka (Rhipidura fuliginosa)

Fantails play prominent roles in Māori legends

Sulphur Cave - yes it did really smell that bad at times... 


Sulphur deposits in a geothermal spring

At the very end of the reserve you reach Lake Ngakoro (the grandfather) which covers 12 hectares and was formed after an eruption more than 700 years ago. The green lake looks like something out of Jurassic Park as it takes the water that flows across the Frying Pan Flat from the Champagne Pool before tumbling over a small waterfall.

Steam rising across the left shore shows the area is geothermally active!

Lake Ngakoro waterfall

Walking around the native bush walk we caught the first glimpse of a snow capped mountain looking over in the direction of Tongariro National Park, it's a pretty exciting thing for me as I've never see anything like this before...

Overlooking the Oyster Pool and Frying Pan Flat

One of our favourite parts of the reserve was right at the end where we saw a crater filled with luminous green water, called the "Devil's Bath"! It seemed unreal but this was the natural colour of the water as it has been stained by the excess water from the Champagne Pool mixing sulphur and ferrous salts.

This picture hasn't been photoshopped, this is how the pool really looks 

As you drive back along the main road there is a short detour to huge boiling mud pool, which is possibly one of the most violent mud pools I've ever seen! This was the site of a large mud volcano which was destroyed through erosion in the 1920′s.

Lying 24 kilometres southeast of Rotorua is Mt Tarawera, a curious-looking mountain, which holds major historical significance for the area in that it was responsible for New Zealand's largest dome volcano eruption and also the country's deadliest eruption. Early Māori and the Europeans who arrived in the 1800's did not realise that Mt Tarawera was an active volcano. At 1111m high, the jagged peaks of Mt Tarawera are made up three domes: Wahanga (bursting open), Ruawahia (the split cave or hole) and Tarawera (burnt cliffs or peaks). On 10th  June 1886, the long-dormant Mount Tarawera erupted violently and beneath Lake Rotomahana, a deadly mixture of water, magma and gas exploded in a chain of eruptions, which created the Waimangu Volcanic Valley as well as destroying the famous Pink and White Terraces that used to cascade down to Lake Rotomahana. The spectacular terraces used to be the biggest sinter formation in New Zealand drawing in tourists to the region before their destruction.

The lake was substantially affected by the eruption and the site where the Pink and White Terraces had once stood became a deep crater over a 100 metres deep. Over time this filled with water and formed a new Lake Rotomahana, much larger than the first. The eruption also formed many new geothermal features, including Waimangu Geyser, the largest in the world, and the largest hot spring in New Zealand, Frying Pan Lake.

Surrounding Māori villages such as Te Wairoa (now known as the Burried Village) were also dramatically showered in tonnes of ash and mud. Although, the final death toll will never been known, it is estimated that between 108 - 120 people perished in what remains the largest eruption in New Zealand since European settlement.

Today, Mt Tarawera is a very different place with a peaceful lake, which has natural hot pools that fringe the lake and even a hot water beach.

To get to Lake Tarawera from Waiotapu, we had to drive all the way back to Rotorua and then back out via the Tarawera Road, past the rather the uninspiring Blue (Tikitapu) and Green (Rotokakahi) Lakes. Having been spoilt with all the tones and colours of Wai-O-Tapu , the lakes don't evoke images of the colours they're named after! To be honest, they're nothing more than recreational lakes, which might have been nice to do some walks from if we had the time but they were nothing special.

Going down to the lake at Tarawera Landing, we were only able to get down to the lakefront, as the Tarawera Trail wasn't open to the public and no date had been set by the Tarawera Trail Trust. Instead, we drove back up to a roadside lookout which gave us spectacular views across the lake.

Lake Tarawera and the mountain from Tarawera Landing

The distinctive Wahanga Dome of Mt Tarawera

1 comment:

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