Evolution of the Dead Sea Brines

The composition of the present-day lake waters, which are Dead Sea brine in the strictest sense, is continuously modified and retained by interacting with these other solutions and by multiple evaporation cycles, with occasional desiccation. The processes are also contolled by mixing along vertical hydraulic pathways along the rift's marginal faults, whose porosity enables brines to sink to depths of geothermal heating. Brine properties and behavior are explained, illustrated, and predicted by application of Jaenecke's version of Gibbs diagrams. The evolution of the Dead Sea brines provides a characteristic hydrochemical model for continental rift basins temporarily connected with the ocean. Geological analogues: The geochemical evolution of the Dead Sea may be a meaningful model for continental rift basins that are formed in the course of the early, preoceanic rifting of a continental plate. The geochemistry is comparable to the Cachloride evaporites of the proto-Atlantic Sergipe basin (northeast Brazil) and the Congo-Gabon basin (west Africa), and with the recent Ca-chloridic Hot Brine pools of the Red Sea. Indeed, continental rifts are predisposed to endorheic drainage, and as such they are typical, morphotectonic evaporite environments. The often anomalously deep subsidence of continental rift basins favors thick evaporate accumulation and water-rock interaction, and their fault systems enable strong local thermal influences.