STRONTIUM IN RAINWATER FROM ISRAEL - SOURCES, ISOTOPES AND CHEMISTRY

Eighteen rain samples from Israel have been analyzed for their chemica l composition and Sr-87/Sr-86 ratios. The Sr-isotopic ratios lie in th e range 0.7078 and 0.7092, and the Sr concentrations vary from 1 x 10( -4) to 9 x 10(-4) meq Sr/l. Soluble salts in rainwater are inherited f rom three major natural sources, seaspray. Recent marine minerals and mineral dust eroded from rock outcrops and soil. A mixing model is for mulated to apply the chemical composition of rain (Cl- and Sr2+) and i ts isotopic Sr-87/Sr-86 ratio, for the identification and estimation o f the Sr sources. All the samples fall within the mixing space predict ed by the model for the three end members mentioned above. The data in dicate that the most important non-seaspray source contributing dissol ved salts to the rains in Israel comprises a mixture of Senonian to Eo cene chalk (and its weathering products) and Recent marine minerals, f rom local and imported sources. Most of the samples (67%) contain 50% or more non-seaspray Sr (i.e., Sr dissolved from dust or Recent marine minerals), whereas 56% of the samples display Sr-87/Sr-86 ratios lowe r than 0.7090. The rest represent mixtures of seaspray and Recent mari ne minerals.