Thick halite sequences are common in the Earth’s geologic record; they were accumulated in deep perennial hypersaline water bodies, saturated to halite and subjected to negative water balance. For decades, evaporites research gained insights from exploring modern shallow hypersaline environments, including the relations between the hydroclimatic forcing and the deposited halite layers. However, there is a knowledge gap in understanding limnological controls on accreted halite sequences in deep water bodies. Such water bodies rarely exist today on Earth, but were common through Earth geological history. The Dead Sea is currently the closest and probably the only modern analog for such environments. Recently, based on direct field measurements, laboratory experiments, direct numerical simulations, and sedimentological investigation, we have shown that there are fundamental differences between deposition at deep basins versus shallow basins, specifically in the seasonal to multi-annual scales and variations of halite solubility with depth. We have found that during the dry summer the epilimnion is warmer, saltier and undersaturated to halite, and that double diffusion flux delivers dissolved salt from the epilimnion into the hypolimnion, resulting in the continuously supersaturated hypolimnion and seasonally undersaturated epilimnion. Thus the stratified structure of the lake’s water column results in focusing of halite deposits into the deep parts of the basin and thinned deposits, or entirely dissolved, in the marginal parts. We further explore the role of laterally variable hydroclimatic conditions to the spatiotemporal dynamics of evaporitic deposits in a deep hypersaline waterbody. We focus on the role of diluted buoyant plume, overlaying part of the Dead Sea surface that laterally spreads from freshwater inflow. The lateral surface salinity variations results in lateral variations in evaporation, double diffusion fluxes, and hence evaporitic layer thickness. These can contribute to the study of the depositional environments of halite units throughout the geological record, following the concept of “the present as key to the past”. At the end of the talk, I will share some management ideas regarding the future of the Dead Sea.
