The chemical and isotopic compositions of thermal waters at Waimangu, New Zealand

The behaviour of antimony released from surface geothermal features in New Zealand

“…This reduction in Sb concentration coincided with an increase in As concentrations and a sudden decrease in pH (from 6.5 to 3.1). Using calculations based on these collected data and data for pH, Li, Cl and SO 4 from Simmons et al (1994), the changes were attributed to a temporary increase in flow from Inferno Crater ( Table 4). The dissolved Sb III minima for sites WM 3-5 (Table 3) were likely to have occurred because there was proportionately less dissolved Sb III in the Inferno Crater than there is in the Frying Pan Lake discharge.…”

High-resolution water column survey to identify active sublacustrine hydrothermal discharge zones within Lake Rotomahana, North Island, New Zealand

“…Based on the fluid composition of geothermal features in Waimangu Valley, and some limited data from hot springs prior to the 1886 Tarawera eruption (Sheppard, 1986;Simmons et al, 1994), characteristics of fluids entering Lake Rotomahana may range from neutral or alkaline chloride waters to acidic steam. As with temperature, pH varies with depth.…”

The Heat Output of the Waimangu, Waiotapu-Waikite and Reporoa Geothermal Systems (NZ): Do Chloride Fluxes Provide an Accurate Measure?

“…From the spring chemistry, Sheppard (1986) suggests a 'parent' water containing 725 mgkg chloride at temperature of 258"C, and Simmons et al (1994) suggests 585 mgkg chloride at 260 "C which give values for Q/Cl of 1.55 and 1.94 MJ/g respectively. Without a knowledge of the chemistry of the deep waters entering through the floor of Lake Rotomahana there must be considerable uncertainty in any estimate, and these must be regarded as upper bounds.…”