Salt dissolution and sinkhole formation: Results of laboratory experiments

Abstract

The accepted mechanism for the formation of thousands of sinkholes along the coast of the Dead Sea suggests that their primary cause is dissolution of a salt layer by groundwater undersaturated with respect to halite. This is related to the drop in the Dead Sea level, which caused a corresponding drop of the freshwater‐saltwater interface, resulting in fresher groundwater replacing the brines that were in contact with the salt layer. In this study we used physical laboratory experiments to examine the validity of this mechanism by reproducing the full dynamic natural process and to examine the impact of different hydrogeological characteristics on this process. The experimental results show surface subsidence and sinkhole formation. The stratigraphic configurations of the aquifer, together with the mechanical properties of the salt layer, determine the dynamic patterns of the sinkhole formation (instantaneous versus gradual formation). Laboratory experiments were also used to study the potential impact of future stratification in the Dead Sea, if and when the “Red Sea‐Dead Sea Canal” project is carried out, and the Dead Sea level remains stable. The results show that the dissolution rates are slower by 1 order of magnitude in comparison with a nonstratified saltwater body, and therefore, the processes of salt dissolution and sinkhole formation will be relatively restrained under these conditions.

Geomechanical modelling of sinkhole development using distinct elements: model verification for a single void space and application to the Dead Sea area

“…Subsidence may occur continuously over a long time depending on the flow conditions and material properties (Goldscheider and Drew, Published by Copernicus Publications on behalf of the European Geosciences Union. Parise and Gunn, 2007;Waltham et al, 2005). Depending on the properties of the overburden (cover or caprock) and the evolution stages, different sinkhole morphologies can be described.…”

Sinkholes, subsidence and subrosion on the eastern shore of the Dead Sea as revealed by a close-range photogrammetric survey

“…e.g. Goldscheider and Drew, 2007;Filin An important scientific question concerns the mechanical and chemical processes of sinkholes formation: is the formation mechanism controlled by pure salt-dissolution (Frumkin et al, 2011;Oz et al, 2016), faults (Closson and Abou Karaki, 2009), both (Ezersky and Frumkin, 2013;Closson and Abou Karaki, 2013;Ezersky et al, 2014) or subrosion (Arkin and Gilat, 2000)? Hereby the role of rock properties and detailed material/(sub)surface water movement is essential for understanding sinkhole evolution and development of early-warning scenarios Parise, 2008;Lollino et al, 2013;Gutierréz et al, 2014).…”

Natural versus human control on subsurface salt dissolution and development of thousands of sinkholes along the Dead Sea coast

“…[], and Oz et al . []). The primary cause of sinkhole formation is salt layer dissolution by intrusion of undersaturated groundwater flowing from the mountain aquifer west of the DS.…”