Chlorine isotope analysis of groundwater to estimate residence time.

Abstract

Chlorine isotope analysis of groundwater was carried out to develop the method for determination of groundwater residence time in the Tono area, Gifu, Japan. Radiogenic chlorine isotope content in the groundwater is as well as that of natural generation rate by neutron flux in the granite. This fact indicates that the groundwater residence time of deep granite may be quite old.