Microphysics of rocksalt flow in nature

Abstract

To model the flow of rocksalt in nature, data on the steady-state rheological behaviour of salt are needed. This paper examines the state of the art in this field. Experimental results show that at 20-200°C and strain rates below - 10 -7 s -1 flow is controlled by dislocation cross-slip and/or climb. Depending on brine content, pressure solution creep and recrystallization can also occur. Combining the various laboratory flow laws leads to a deformation map which predicts that flow under natural conditions should be dominated by climb-controlled dislocation creep, and/or pressure solution. This picture is confirmed by microstructural analysis of natural salts, justifying the application of laboratory flow laws to model salt tectonic processes.