Hot Spring Areas with Acid–Sulphate–Chloride Waters

Abstract

WHITE¹, in a review of the thermal waters of volcanic origin, pointed out the problem of springs with a large flow of acid–sulphate–chloride water, such as Frying Pan Lake (or more correctly, Echo Crater) in the Waimangu area of the Rotorua Taupo graben. This has a daily discharge of 800 kgm. of sulphuric acid. White remarked that the surface oxidation of hydrogen sulphide to sulphuric acid in the type of porous ground favourable to this process could account for only an insignificant part of the total production of sulphuric acid. Typical hot underground chloride water, as at Wairakei, is nearly neutral in reaction, and it seems unlikely that water appreciably acid could be stored underground without attack on the country rock. This communication suggests an explanation for the high-output acid–sulphate–chloride type of spring.