| Abstract |
The Waimangu Thermal Valley was exposed as a consequence of the eruption of Mt Taraweraon June 10,1886.The cyclic nature of geothermal activity in the valley was demonstrated by the Waimangu Geyser which played with a 36 hour period from 1900to 1904,and is exhibited today by the Inferno Crater Lake. Inferno Crater lake is located in the side of Mt Hazard (a small rhyolite dome) 15m above other features in the valley. The lake water is a chloride fluid that has undergone 29% mixing with an acid-sulphate fluid. is a minor component. Inferno Crater lake undergoes a quasi-cyclic movement in water level and temperature over a six week period. However from January to May 1990,a temporary cycle of frequent minor was established. A geochemical survey over this period Na, K, B and Li show a sympathetic variation in concentration with while Si, Fe, Al, NH3 and Mg vary sympathetically with Correlations between fluctuations in temperature, SO4 concentrations and mass flow suggest that condensation of a steam into the lake is the dominant factor controlling the cyclic behaviourof the lake. |