Eleven rainwater samples from Israel have been analyzed for their isotopic 36Cl/Cl ratios and their soluble salt content. The rains display a range of 36Cl/Cl ratios between 1.8 × 10-15 and 50 × 10-15, and chloride ion concentrations of between 0.3 and 4.2 meq Cl- l. The ratios between the concentrations of Na+, Mg2+ and Cl- in the samples demonstrate a clear marine origin for these ions in the rainwater. Although the stable 35Cl isotope in rainwater is marine in origin, while the accompanying 36Cl radioisotope is non-marine, both are linearly and positively correlated in chloride-rich ( > 1 meq Cl/l) rains. The 36ClCl seawater solute relationship may be explained as result of a mixing process between two chloride-bearing sources: (a) sea-spray laden air with a low 36Cl/Cl ratio, and (b) a Cl-rich mineral dust reservoir, with a high 36Cl Cl ratio. Both are introduced and admixed into the atmosphere during storms. The possibility of a high 36Cl/Cl ratio stratospheric end-member is rejected in view of the non-marine nature of the chlorine therein.
ASJC Scopus subject areas
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science