Some rare treasures are hidden within the Petrology collection of the Natural History Museum, and this brunch of a bush, encrusted with sinter, which formed prior to 1886 around hot springs on the shores of the old Lake Rotomahana (warm lake) in New Zealand, is one of them.
Read on to learn about the Pink and White Terraces, a natural wonder of the world, regarded by the Māori as a taonga (a treasure), their tragic fate and how specimens in the museum collection are helping current research.
What is a siliceous sinter and how it forms?
Siliceous sinter is a deposit of amorphous silica that forms around hot springs around volcanic terrains, where deep silica-rich waters heated by magma, emerge to the Earth’s surface. Due to the rapid cooling at the surface, silica is deposited. This material is known also as geyserite.
The Pink and White Terraces of Lake Rotomahana
The silica precipitated by the evaporating waters was forming layers of encrusting sinter, which gradually over about 1,000 years (Keam, Ronald F. 2016) formed many pools and steps. This active, yet slow process formed attractive bathing pools, which for the majestic appearance, the size, and for the warm water, were considered to be the eighth wonder of the natural world.
These were New Zealand’s most famous tourist attraction during the mid 19th century, and the beauty of the terraces, not only attracted tourists but also inspired several artists.
Today, the only visible parts of this natural beauty, are samples of the Museum collections, pictures, and works of arts inspired by these natural wonders. An example of these is the oil painting executed by British-born artist Charles Blomfield in 1882, prior to the destructive volcanic event of 1886.
The eruption of Mt. Tarawera of 1886
In the early hours of 10th June 1886, a disastrous volcanic eruption of Mount Tarawera took place. The eruption was that powerful that it split the mountain and created the Waimangu Volcanic Rift Valley. The nearby land was covered with millions of tonnes of volcanic ash, mud and debris on average 20 metres (66 ft) thick (“Waimangu: Geology”. GNS Science, 2015).
The devastating effects of the eruption through the bottom of the old lake changed the surrounding landscape forever (de Ronde et al., 2016). Within months of the eruption the new lake began to fill as the historical outlet for the old lake was dammed by debris; most of the new geothermal features were drowned within a few years and today the lake is ~120 m deep at its deepest point (de Ronde et al., 2016) ~20 m deeper than expected.
The Pink and White Terraces of Lake Rotomahana were thought to have been completely destroyed until researchers in 2011 carrying out high-resolution mapping of the lake floor reported discovering part of the Pink Terraces and White Terraces (“Terrace discovery most surprising yet”. One News. 10 June 2011).
Why are these NHM specimens Important?
These natural wonders were long used by the local Māori to soothe and heal bodies. These healing waters became a popular destination for international visitors in the 19th and early 20th centuries, bringing economic benefit to Māori villagers living nearby. They offered services as guides and boatmen, entertaining tourists with traditional dancing and singing. It is clear that these natural spas were extremely important to the locals, and their destruction was a disgrace to them.
Recently, pieces of Rotorua’s Pink and White Terraces have attracted very much the interest of private collectors, becoming the most sought-after objects in auctions.
Unfortunately, some fakes are circulating, and New Zealander scientists are using the NHM collection to fingerprint the originals.
The White and Pink Terraces of Rotomahana live on as we have precious historical specimens in our collections. These are a very important example of unique historical material being made available for analysis via the museum.