Oxygen and Hydrogen Isotopes in Thermal Waters at Zunil, Guatemala

Abstract

Enthalpy chloride relations suggest that a deep reservoir exists at Zunil with a temperatures near 300°C. Water from that reservoir moves to shallower and cooler local reservoirs where it mixes with diluted water and then attains a new water rock chemical equilibrium. This mixed water, in turn, generally is further diluted before being discharged from thermal springs. The stable isoptic compositions of the thermal water indicates the recharge for the deep water at Zunil comes mainly from local sources. The presence of measurable tritium, which suggest that the deep water has been underground about 20 to 30 years, also indicates a local source for the recharge.