Previous results of sulfur isotope analyses of sulfides from the Sullivan deposit have indicated a relative enrichment in 34 S in the western section of the orebody. This study provides further detail from intensive sampling of 15 drill cores that transect the massive pyrrhotite zone. The pyrrhotite fabric shows a foliation that may be bedding, kink bands, and twin orientations which are consistent with horizontal maximum compression. Sulfur isotope data from 146 pyrrhotite separates give values that range from --5.0 to +4.0 per mil (mean 0.0 per mil). A volume 200 by 400 m and 20 m thick is delineated in which pyrrhotite is enriched in 34 S. This anomaly is attributed to the high temperatures associated with the site of upwelling metal-bearing solutions.Samples were analyzed by X-ray diffraction for copper, zinc, lead, and tin. No statistically significant correlation was found between any of these metals and the pattern of delta 34 S variation.