DETERMINATION OF VOLATILE SULFUR SPECIES IN SOIL SAMPLES OF INTEREST FOR PROSPECTING FOR METAL SULFIDE DEPOSITS

A method for the determination of volatile reduced sulphur species, na mely carbonyl sulphide, dimethyl sulphide, carbon disulphide and dimet hyl disulphide, adsorbed in soil samples overlying sub-surface metal s ulphide mineral deposits is described. Heating time acid temperature a nd the headspace gas are critical parameters determining the final com position and yield of the desorbed mixtures. Heating at 95 degrees C f or 1 h with nitrogen in the headspace provided maximum yields of the c ompounds reflecting the desorbed species. Longer heating times generat e mixtures of sulphur compounds that correspond to thermal decompositi on of the soil organic matter with no value for prospecting purposes.