Researchers find meter-high mineral chimneys in the Dead Sea, a potential sinkhole warning

Researchers have discovered astonishing mineral formations at the bottom of the Dead Sea, including meter-high chimneys formed by the spontaneous crystallization of minerals from groundwater with an extremely high salt content. Called "white smokers," these chimneys are formed by the expulsion of hypersaline fluid from the lake floor and have been found to be an important early warning indicator for sinkholes.

The findings of the research team were reported in the journal Science of the Total Environment, and were subsequently published in Die Zeit, Süddeutsche Zeitung, and Science Daily, among others. 

The scientists, including Dr. Christian Siebert, a hydrogeologist at the Helmholtz Centre for Environmental Research (UFZ), have been studying how the dynamics of the groundwater system in this region are changing. Divers deployed by Dr. Siebert identified strange chimney-shaped vents on the lake floor, many of which were one to two meters high, but some reaching heights of over seven meters with diameters of two to three meters. These chimneys resemble hydrothermal chimneys discovered in oceanic ridges, but "the system is completely different," according to Dr. Siebert.

The chimneys are formed by the spontaneous crystallization of minerals when groundwater with an extremely high salt content flows up out of the lake floor. This groundwater, originating from surrounding aquifers, penetrates into the saline lake sediments, leaching out extremely old and thick layers of rock consisting mainly of the mineral halite. The groundwater becomes charged with salt, transforming into brine. As this brine has a slightly lower density than the water of the Dead Sea, it rises like a jet. "It looks like smoke, but it's a saline fluid," Dr. Siebert explained.

Contact with the lake water causes the dissolved salts, especially halite, to spontaneously crystallize after emerging from the lake bed. This precipitation gradually leads to the formation of these astonishing chimneys, which can grow by several centimeters within a single day. The salts quickly deposit and form bright columns, giving these formations their name of "white smokers."

The discovery of these chimneys is particularly significant because they can serve as an outstanding forecasting tool for locating areas at risk of collapse in the near future. Sinkholes, which are subsidence craters up to 100 meters wide and up to 20 meters deep, have formed in the vicinity of the Dead Sea in recent decades, posing a significant hazard to the population. These sinkholes are formed by karstification of the subsoil, caused by the dissolution of massive layers of salt due to the circulation of groundwater. This karstification forms giant cavities above which the ground can collapse at any time.

The research team was able to show that the chimneys had formed wherever the land surface subsequently collapsed over a large area. The karstification process had apparently been especially efficient in those areas. "This makes the white smokers an outstanding forecasting tool for locating areas that are at risk of collapse in the near future," Christian Siebert said. "To date, no one can predict where the next sinkholes will occur. They are also life-threatening and pose a threat to agriculture and infrastructure."

Autonomous watercraft equipped with multibeam echosounders or side-scanning sonar systems could be used to map the chimneys to a high degree of precision. "This would be the only method to date, and a highly efficient one, for identifying regions at risk of imminent collapse," Dr. Siebert explained. Such mapping could allow for very good predictions of which areas are at risk of collapse in the near future.

The Dead Sea, located between Israel, Jordan, and the West Bank, is a highly dynamic system and an ecosystem of extremes. Over the past 50 years, a notable lowering of the Dead Sea's level has been observed, nearly one meter per year, reaching approximately 438 meters below sea level. This sinking is due to the Dead Sea being cut off from key tributaries and, due to drought and heat, losing a lot of water through strong evaporation. The declining water level has significant consequences, especially for groundwater.

The groundwater level in the region is falling, making it increasingly difficult for neighboring countries to access groundwater resources. The circulation of freshwater through the ancient saline sediments present in the region's subsoil is believed to cause the formation of sinkholes. Researchers from various fields have been studying the Dead Sea's decline for several years to understand the evolving dynamics of the region.

This article was written in collaboration with generative AI company Alchemiq