Snapshot of hot-spring sinter at Geyser Valley, Wairakei, New Zealand, following anthropogenic drawdown of the geothermal reservoir

WATTS-HENWOOD, NICK; CAMPBELL, KATHLEEN A.; LYNNE, BRIDGET Y.; GUIDO, DIEGO M.; ROWLAND, JULIE V.; BROWNE, PATRICK R.L.

GEOTHERMICS

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017 vol. 68 p. 94 - 114

0375-6505

From the 1950s, extraction of thermal fluids to generate electricity at Wairakei, Taupo Volcanic Zone, New Zealand, heralded a rapid transformation of surface manifestations at nearby Geyser Valley, 1 km NW of the power station. Active geysers and hot-springs fed by alkali-chloride waters ceased by 1968, replaced by acidic steam-dominated conditions. Field relationships indicate geothermal features are fault-controlled. Siliceous hot-spring (sinter) deposits represent spring-vent to distal marsh settings. The dominant mineralogy is opal-A, with some minor clay alteration. Some textures show silica dissolution and re-precipitation. Thus, only minor alteration and diagenesis has occurred, with vegetation overgrowing the extinct sinter.