The origin of sulphates: an example of sulphur isotopic applications

This review is concerned with the technique of stable isotope analyses (δ³⁴S‰) as a means of studying the sulphur cycle with particular emphasis on the formation of sulphate evaporites such as gypsum (CaSO₄.^2H ₂O). Gypsum is found in all settings that promote evaporation, including hot and cold desert environments. The technique of sulphur isotopic analysis lends itself to constraining the primary sources of sulphur as well as associated pathways of sulphur dispersal, which lead to the formation of sulphate. The review features gypsum in caves, salt pans and limestone walls with sulphur sources ranging from the marine environment to bedrock.