The source and age of groundwater brines in the Dead Sea area, as deduced from 36Cl and 14C

Abstract

36Cl and 14C analyses of saline groundwater in the Dead Sea area were performed in order to study the chloride source of the brines and their age. Similarity among the 36Cl/Cl ratio in saline groundwater (7−15 × 10 −15), Dead Sea water (12.8 × 10 −15), and in an halite layer (11 × 10 −15) indicates that they all have a similar chloride source. The 36Cl/Cl ratios also suggest a significant contribution of chloride from rain water. It is postulated that groundwater brines are the result of direct infiltration of brines from a precursor Dead Sea lake, such as Lake Lisan, which covered the area in the past. This lake underwent several evaporation stages precipitating halite and infiltrating brines of varying chemical composition. 14C data (3.8–25.8 PMC) indicate that the percolation of brines into the sediments took place more than 9,000 years ago.