Fluid inclusion evidence for the deposition and diagenesis of the Patience Lake Member of the Devonian Prairie Evaporite Formation, Saskatchewan, Canada

Abstract

Low bromine concentrations, radiometric ages, textural relations and large-scale dissolution and collapse features in Devonian potash deposits of the Elk Point Basin in southern Saskatchewan indicate that diagenetic processes and late influxes of water have variably recrystallized the salts. Lack of correlation between homogenization temperature ( T h), δD or δ 18O values of fluid inclusions in the salt with stratigraphic position further indicates that the sequence is not primary. The stable isotopic compositions of fluid inclusion waters, including those in chevron-texture halites, are not those expected for primary crystallization waters and, in conjunction with T h, indicate recrystallization occurred at temperatures of 35–70°C from water originating in formations above the Prairie Evaporite Formation. Using T h as an estimate of the depth of burial and stable isotopes as indicators of the source of fluids, three major recrystallization events related to the evolution of the Elk Point Basin can be recognized.