M. Paul, M. Fink, O. Meirav, Hebrew University, Jerusalem, Israel
A. Kaufman, M. Magaritz, O. Meirav, Weizmann Institute of Science, Rehovot, Israel
W. Henning, W. Kutschera, Argonne National Laboratory
Nature 321 (1986) 511-515
The recent breakthrough in our ability to detect the radioactive isotope 36 Cl (half-life T 1/2 = 301,000 yr) at natural levels by accelerator mass spectrometry allows the processes of salination of water systems to be studied in a new way by distinguishing the chloride content originating in young rainwaters and their subsequent evaporation from that generated by the leaching of ancient rocks. Results for the Jordon River/Deas Sea system show that the amount of chloride leached from rocks ranges from ~70% in source springs to >90% in water bodies downstream. Furthermore, the amount of water left after evaporation decreases from ~50% in the source springs to 20% in the intermediate Lake Kinneret. In the terminal Dead Sea, 99% of the stable chloride originates from ancient rocks and evaporite formations while ~80% of its 36 Cl content is of meteoric origin. Using 36 Cl measurements, we estimate accumulation time of the Dead Sea salt to be 19,000-25,000 yr.