Salt weathering (i.e., the cracking of rocks by salts) plays a central role in the physical weathering of rocks in desert landscapes. However, the physicochemical processes and the environmental drivers of this cracking mechanism remain poorly constrained. The present study focuses on rocks along the Dead Sea coast that exhibit salt-driven cracking. We present a novel stable isotope investigation of water (i.e., δ¹⁸O and δD), from salts cumulates within fractures, and compare these against the distinct isotopic composition of local atmospheric and Dead Sea waters. Isotopic constraints on the source of water extracted from salts in the cracks are expected to shed light on the environmental drivers of the salt- cracking mechanism.

Fractures within alluvial casts were forced-open to reveal internal salt cumulates, which were extracted into borosilicate glass ampoules that were flame sealed in the field. The ampoules, containing ca. 200 to 800 nanolitres H2O, were then cracked on a bespoke heated line connected to a Picarro L2140i for direct δ¹⁸O and δD analysis.

Preliminary results show highly elevated δ¹⁸O values in respect to typical natural meteoric waters and varying δD values. Both δ¹⁸O and deuterium-excess (d-excess = δD-8*δ¹⁸O) values argue that the extracted water from salts in the cracks underwent significant evaporation. These preliminary results serve as proof of concept for the ability to analyze the isotopic composition of water in salts and also open new frontier for investigation of the role of atmospheric moisture in salt weathering processes.