Water Geochemistry at Castle Hot Springs, Arizona

Abstract

A geochemical survey of springs and wells in the Castle Hot Springs area, Arizona, shows that three groups of waters can be distinguished by salinity and chemistry. The thermal waters of Group I range from 640 to 820 ppm TDS, and the waters contain high concentrations of SiO2, Li+ and F-. The non thermal waters of Group II range from 380 to 580 ppm TDS and contain low concentrations of SiO2, L+ and F-. The non thermal waters of Group III range from 1600 to 1650 and contain the highest concentrations of Li+, C1- and SO3+. The discrepancy between the low measured surface temperature at Castle Hot Springs, and the high temperature estimated from chemical geothermometry suggest thermal waters may have cooled either by conduction, boiling or mixing. The chalcedony mixing model yields a reservoir temperature of 95°C and a cold water fraction of 56%.