The Dead Sea is a unique body of water with extraordinary conditions that have led to the formation of massive salt deposits, known as “salt giants.” Researchers have discovered how these giant salt formations form over time, and the process is unlike anywhere else on Earth.
According to UC Santa Barbara mechanical engineering professor Eckart Meiburg, lead author of a recent paper published in the Annual Review of Fluid Mechanics, the Dead Sea’s salt giants can be kilometers wide and thick. But how did they form?
The answer lies in the combination of evaporation, precipitation, and saturation processes that occur within the lake. The Dead Sea is a saltwater terminal lake, meaning it has no outflow, and water leaves the lake primarily through evaporation. This process has been shrinking the lake for millennia, leaving behind salt deposits as it does so.
Temperatures along the water column also play a crucial role in the formation of these giant salt deposits. The Dead Sea was once layered with a less dense warmer water at the surface and a more saline, cooler layer at depth. However, this stratification changed in the early 1980s when the Jordan River was partially diverted, resulting in evaporation outpacing freshwater inflow.
As a result, the surface salinity reached levels found at depth, enabling mixing between the two layers and transitioning the lake from meromictic to holomictic. This process led to the formation of unique salt structures, such as halite crystal precipitation or “snow” that was more typical in cooler seasons.
Researchers have observed that during the summer, while evaporation increased the salinity of the upper layer, salts continued to dissolve due to warmer temperatures. This leads to a condition called “double diffusion” at the interface between the two layers, where sections of saltier water cool down and sink, while portions of the cooler water warm up and rise.
This complex interplay of processes creates the conditions for salt deposits to form in various shapes and sizes. In contrast to shallower hypersaline bodies where precipitation and deposition occur during dry seasons, the Dead Sea’s processes are most intense during winter months.
The researchers believe that this year-round “snow” season at depth explains the emergence of salt giants found in other saline bodies like the Mediterranean Sea. By studying these unique processes, scientists can gain a fundamental understanding of how these giant salt formations form and what they reveal about the geological history of our planet.
Furthermore, research into the sediment transport processes on emerging beaches may also provide insight into the stability and erosion of arid coastlines under sea level change, as well as the potential for resource extraction.
Source: https://phys.org/news/2025-07-dead-sea-salt-giants-reveal.html