Geochemistry of the Ketetahi hot spring area

Abstract

Ketetahi hot springs occupy a small confined area on the northern flanks of Mt Tongariro volcanic complex which has been active in recent times. Waters are of the acid-sulphate type, locally neutralized by high concentrations of ammonia. Superheated steam emanates from two vigorously discharging vents. Water compositions and secondary minerals are products of strong cation leaching. The chemical and isotopic composition of surface discharges is interpreted by a mechanism in which near-surface waters are heated by an underlying body of steam.