Tongariro National Park Highlights
It is generally believed that the Mangatepopo Valley was glacially carved out during the last ice age and subsequently partially in-filled by lava flows from Ngauruhoe.
Note the different colours on the lava flows as you walk up the valley. The surface colour of younger lava is darker and absorbs much of the suns' heat - this is a harsh environment for plants to grow and the reason why the youngest flows only have a few plants, lichens and moss. The older flows have progressively more species and large plants, which take advantage of the slow build up of precious soil. The vegetation has also been modified by fire and farming.
As you descend from the northern edge of Red crater you will come across three water-filled explosion craters called the Emerald Lakes. Minerals leaching from the adjoining thermal area, such as sulphur, cause their brilliant colour. The Maori name is Ngarotopounamu meaning greenstone-hued lakes. Despite being surrounded by steam vents called fumaroles, these lakes are very cold and freeze in winter.
Formed in an old volcanic lava vent, this is a freshwater lake up to 16 metres deep. Once again, dissolved minerals are responsible for its distinctive colour, and its waters are cold and acidic. Its Maori name is Te Wai-whakaata-o-te-Rangihiroa, which translates as Rangihiroa's mirror. Te Rangihiroa was the son of local chief Pakaurangi, and is said to have explored the Tongariro volcanoes about AD 1750. This lake is tapu (sacred). Do not swim in or eat food around the lake.
Click here for a detailed decrisption of the Tongariro Crossing track.