The analysis of fluid inclusions in halite

A technique has been developed to drill into fluid inclusions in halite, to extract the inclusion fluids, and to determine the concentration of all of the major and some of the minor constituents in these fluids. The minimum diameter of usable fluid inclusions is ca. 250 μm. After dilution, the fluids are analyzed by ion chromatography and coulometry. Uncertainties in the concentration of the major cations and anions is on the order of 4%. The analytical scheme provides much more precise analyses of inclusion fluids than have been available to date. The analyses are a useful starting point for reconstructing the composition of the seawater from which the evaporite brines evolved.