The relation between the physico-chemical characteristics of thermal water and the nature of their siliceous sinter deposits

Abstract

Siliceous sinters (hot spring rocks) form by evaporation of near-neutral, alkali-chloride silica-rich thermal waters. Their importance resides in their capacity for recording environmental conditions and their relation to the existence of a geothermal reservoir at depth. Previous studies have shown that sinter textures are commonly controlled by hydrodynamic conditions, whereas their mineralogy and chemistry is controlled by chemical composition of thermal waters. However, the effect of altitude, wind velocity and discharge rate are still poorly constrained. Here we present preliminary data of an experiment developed at the El Tatio geothermal field in northern Chile, designed to determine silica accumulation rates and textures developed in sinter, and their relationship to environmental and hydrodynamic conditions.