June Fabryka-Martin, S.N. Davis, University of Arizona

D. Elmore, Argonne National Laboratory

Nuclear Instruments and Methods B29 (1987) 361-371

Since the first AMS measurements of ³⁶ Cl in 1978, this cosmogenic radionuclide has proved to be a versatile tracer of hydrologic processes in over 20 field studies. Natural ¹²⁹ I also appears to be useful for studying hydrologic processes although incomplete understanding of its production in nature and geochemical behavior largely limits interpretation to qualitative discussions. The range of hydrologic applications demonstrated for these radionuclides covers: estimation of residence time of water in the subsurface and net infiltration in and soils; evaluation ofion filtration, leaching of connate water, and salt dissolution as sources of ground-water salinity; estimation of lithospheric thermal-neutron fluxes; and emanation and migration characteristics of fission-product ¹²⁹ I in different geochemical environments.