Geochemical and Hydrological Assessment of Thermal Features in the Vicinity of the Champagne Pool in the Waiotapu Geothermal System

Abstract

Waiotapu thermal area is located within the Taupo Volcanic Zone of Central North Island of New Zealand. It has the largest area of surface thermal activity and has been the subject of various investigations.
In this paper water chemistry was used to evaluate the compositions of water from nine springs in the vicinity of the Champagne Pool. The spring waters can be classified into three groups: neutral chloride waters, mixed sulfate-chloride waters and sulfate waters. Constant mass ratios of CI:B in spring waters show a narrow range suggesting a common deep source.
Surface temperatures are near boiling with a maximum of 97 C. K-Na geothermometry indicates subsurface equilibrium temperatures of up to 297 C. Silica geothermometry is less reliable due to the diluted nature of water springs, but gives a maximum value of about 210 C.
The Champagne Pool and the Weather Pool have increased in CI and SO4 concentrations by about 100 ppm since their analysis in 1983.
This paper about water chemistry delineates the most probable location of the upflow zones, where the deep chloride water ascends to the surface in the vicinity of Champagne Pool.