Sinter Chemistry: Towards a Diagnostic Signature and a Sinter Geothermometer

Abstract

Sinter samples from Atiamuri, Ohaaki, Waiotapu and Tokaanu geothermal fields in the Taupo Volcanic Zone, New Zealand were subjected to major and trace element analysisby Xray fluorescence spectrometry. Silica and water are the major components, with assuming importance in sinters from Ohaaki, which are composed of an intimatemixture of calcite and silica. Most of the trace elements examined (As, Ba, Cr, La, Ni, Pb, Rb, Sr, Th, V, Y, are often present in concentrations of Arsenic, however, is commonly enriched (up to while Sr shows a dramaticincrease in concentration (up to when calcite is present in the sinter. The As-Sb-TI-Hg association may be diagnostic and discriminate sinters from other siliceous lithologies. Although sintersare heterogeneousdeposits, ratios of constituentsin sinters across a field are reasonably consistent. A linear relationship exists between the ratio in the water and that in the sinter. This was used to a geothermometer, which has the equation