Isotopic methods in hydrogeology and their application to the Underground Research Laboratory, Manitoba

摘要

This review examines isotopic methods used to determine groundwater sources, residence times and processes of geochemical evolution that have been published in the international literature, with specific reference to AECL's experience in these methods and applications to groundwaters at the Underground Research Laboratory (URL), Manitoba. The program of groundwater sampling and analysis currently being planned for the URL area over the next several years will concentrate on specific isotopic measurements that may assist in understanding the groundwater flow system at the URL site. These results will add to the existing data for the URL area and indicate which isotopes are most useful when applied to the known groundwater flow system of the URL. This program of study is especially important because it not only uses standard geochemical and isotopic measurements (e.g., major ion, trace elements, (sup 2)H/(sup 18)O, (sup 14)C, (sup 34)S) of groundwaters, but will determine values of more exotic and unusual ratios, such as (sup 6)Li/(sup 7)Li, and B(sup 11)/B(sup 10), whose potential for understanding groundwater geochemical evolution is largely unknown at present. In addition, the more established but equally complex methods of isotopic analysis, to determine (sup 3)He/(sup 4)He, (sup 36)Cl/Cl and (sup 129)I/I, will be used to assess their potential for adding to the hydrogeochemical understanding of flow paths in crystalline rock. (author). 182 refs., 11 tabs., 27 figs. (Atomindex citation 27:013737)