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Thirty-five S isotope analyses obtained from six carbonatite complexes from the Superior Province, Canadian Shield, ranging in age from 1,897 Ma to 1,093 Ma, have δ34SCDT values of between −4.5‰ and +3.4‰. Pyrrhotite, chalcopyrite and pyrite mineral separates were used. Each complex possesses its own distinct range and mean S isotope composition. The range for Schryburt Lake is: −4.5‰ to −3.4‰ ( mean = −3.9‰), for Big Beaver House: −3.6‰ to −1.5‰ (mean = −2.2‰), for Cargill: −1.5‰–+0.5‰ (mean = −0.7‰), for Spanish River: −0.1‰–+0.1‰ (mean = 0.0‰), and for Firesand River: +1.3‰–+3.4‰ (mean = +1.7‰). A single sample from Carb Lake yielded a δ34SCDT value of +2.8‰. Differences in isotope compositions can be related to isotope effects brought about during melt generation and emplacment, such as variations in fo2 and temperature. The different S and C isotope data for most complexes, however, suggest that the parental melts could have been generated from a heterogeneous mantle source, although process-driven changes cannot be completely ruled out. [ABSTRACT FROM AUTHOR]