Combined Raman spectroscopy and low temperature microthermometry: identification of salts in fluid inclusions

Microthermometry of fluid inclusions is a very useful technique to estimations of fluid inclusions salinities but do not give information about the true nature of salt components. Several complex techniques have been developed for the analysis of elements and ions in fluid inclusions. Destructive methods include laser ablation with ICP-MS or OES and ion chromatography (crush-leach). These techniques only provide absolute ratios of elements in inclusions. Raman spectroscopy can be used to identify the major type of salts dissolved in aqueous solutions in fluid inclusions. The advantage of this technique is two-fold: 1) accurate estimation of true melting temperatures of phases which are difficult to observe; and 2) determination of the type of dissolved salt from the presence of salt-hydrate at low temperatures, which are Raman active