Feature
Type |
Definition
|
| Geyser |
Any naturally occurring geothermal spring that occasionally or frequently erupts producing an intermittent or continuous discharge by the evolution of a phase dominated by steam or other gases, vigorous enough to eject forcefully liquid water by surging, boiling, throwing, splashing, or jetting it into the air above a static water level or vent opening. This includes hot water geysers, perpetual spouters, soda geysers, and crypto-geysers. The area of a geyser comprises that of the spring basin and the area covered (perhaps intermittently) by surface water composed of the undiluted discharge from the geyser, and by any sinter deposits created by that discharge. |
| Spring Vigorously Depositing Sinter |
Any naturally occurring geothermal spring that vigorously deposits sinter on surfaces covered by its outflow, or any submerged geothermal spring that would be likely to vigorously deposit sinter if it were no longer submerged. The area of a spring vigorously depositing sinter comprises that of the spring basin, together with the area covered by any surface water composed of the undiluted outflow from the pool and any sinter deposits created by that outflow. |
| Recent Sinter |
Any sinter body that has received natural sinter deposition since 1900 but which is no longer receiving natural sinter deposition. This includes carbonate sinters (travertine). The area of a recent sinter body consists of that of all interconnected sinter in a single occurrence and the land formations underlying it. |
| Geothermal habitat on heated ground or cooled acid ground |
Any area of terrestrial habitat of thermotolerant indigenous species on current or formerly geothermally heated ground. |
| Habitat dependent on geothermally-altered atmosphere |
Any area of terrestrial habitat of indigenous thermotolerant species that is tolerant of, or dependent on geothermal alteration of, atmospheric conditions.
|
| Mud Geyser |
Any naturally occurring geothermally heated mud pool that occasionally or frequently erupts. The eruption produces an intermittent or continuous discharge caused by the evolution of a phase dominated by steam or other gases. This must be vigorous enough to forcefully raise liquid mud by surging, boiling, throwing, splashing, or jetting it into the air above a static water level. This includes mud volcanoes exhibiting this behaviour. The area covered by a mud geyser includes the mud pool, its banks, and any mud formations built up by the ejection of mud from the pool. |
| Molten Sulphur-Producing Spring |
A hot spring whose water supply passes through elemental sulphur bearing rock at a temperature sufficiently high to melt the sulphur (119 °C) and bring it to the surface. |
| Superheated Fumarole |
Any naturally occurring vent, including those found underwater, whose main discharge consists of steam and other gases of geothermal origin with a temperature greater than the local boiling temperature of water. The area of a fumarole consists of the vent, any surface accumulating mineral deposits derived from its gases, and any ecosystems dependent on the heat and fluid flowing from the vent. |
| Mud Pool |
Any naturally occurring basin of turbid water or mud heated (or recently heated) by geothermal processes. The area of a mud pool comprises that of the pool itself, its banks, and any mud formations built up by the ejection of mud from the pool. |
| Geothermally-Influenced Aquatic Habitat |
Any area of naturally occurring seasonal or permanent aquatic habitat of thermotolerant, thermophilic, or extremophilic indigenous species in a water body or part thereof influenced by natural geothermal input, or in a Geothermally-Influenced Water Body. |
| Geothermally-Influenced Water Body |
Any naturally occurring wetland, lake, pool, or stream, or portion thereof (including the bed and banks), whose chemical or temperature profile is significantly influenced by natural geothermal input and which is either:
- a standing water body of greater than 30 m2 surface area, or
- a flowing water body longer than 100 metres and with a flow greater than 0.1 m3/sec
in which natural geothermal input has caused the water to have:
- a temperature of greater than 30°C, or
- a chloride concentration of greater than 120 g/m3, or
- a sulphate concentration of greater than 60 g/m3, or
- geothermal mineral deposition,
measured at least 7 days after a significant rainfall event.
In large or poorly mixed water bodies, only those portions which meet the above conditions are included in this definition.
|
| Hydrothermal Eruption Crater |
Any naturally occurring crater produced by the explosive boiling of geothermal water without the direct involvement of near-surface magma, and by the consequent ejection of material derived from the rock matrix. The area of a hydrothermal eruption crater comprises that of the crater, its sides, and the ejecta deposited around the crater. |
| Culturally Significant Feature |
Any geothermal surface feature, whether artificial, natural, or modified that is deemed significant following consideration of the criteria for determining significance of cultural heritage resources in Appendix 4 of the Waikato Regional Policy Statement. |