Horomatangi Reef is a pristine geothermal system on the bed of Lake Taupo.
The Horomatangi Reef overlies an underwater geothermal system on the bed of Lake Taupo, with two distinct hydrothermal vent areas producing hot water and gases.
Hydrothermal chimneys up to 30cm tall have been built up by thermophilic micro-organisms. There are also thermophilic bacterial mats and sponges.
Horomatangi is classified as a Protected Geothermal System by Waikato Regional Council.
The Horomatangi Reef is protected by its inaccessibility and is pristine.