Stable Isotope and Geochemical Reconnaisance of the Mokai Geothermal System, Taupo Volcanic Zone

Abstract

S table isotope and geochemical da t a from natural features at Mokai are consistent with a hot water upflow zone in the central area, and a shallow lateral flow with dilution towards the north- east. Chemical water and gas analyses indicate minimum temperatures of and respectively. The hydrogen-water i sotope temperatures are while the methane-carbon dioxide isotopic temperature of higher than corresponding values in Wairakei o r Broadlands), suggests a high temperature source at considerable depth in the central area. Oxygen-18 and deuterium analyses of thermal and ground-water support the proposed hydrologic model.